Teaching Material

on AAG 112 Introduction to (2=1+1)

Compiled by: Dr. Shashank Tyagi Asstt. Professor cum Junior Scientist & Pravesh Kumar Asstt. Professor cum Junior Scientist

Deptt. of Agronomy Bihar Agriculture University, Sabour, Bhagalpur, Bihar-813210 Introduction to Forestry (2=1+1) Theory:

S.N. Particulars No. of Lectures 1. Introduction – definitions of basic terms related to forestry, objectives of 1 , classification, salient features of Indian Forest Policies. 2. Forest regeneration, Natural regeneration - natural regeneration from seed 2 and vegetative parts, , , root suckers. 3. Artificial regeneration – objectives, choice between natural and artificial 2 regeneration, essential preliminary considerations. 4. Crown classification. Tending operations – weeding, , – 1 mechanical, ordinary, crown and advance thinning. 5. Forest mensuration – objectives, diameter measurement, instruments used 1 in diameter measurement. 6. Non instrumental methods of height measurement - shadow and single pole 2 method; Instrumental methods of height measurement - geometric and trigonometric principles, instruments used in height measurement. 7. stem form, form factor, form quotient, measurement of volume of 2 felled and standing , age determination of trees. 8. – definitions, importance, criteria of selection of trees in 1 agroforestry, different agroforestry systems prevalent in the country, 9. , Taungya. 2 10. Alley cropping. 1 11. Wind breaks and shelter belts, home gardens. 1 12. Cultivation practices of two important fast growing tree species of the 2 region. Total 18 Practical: 1. Identification of tree-species. 3 2. Diameter measurements using calipers and tape, diameter measurements of 2 forked, buttressed, fluted and leaning trees. 3. Height measurement of standing trees by shadow method, single pole 2 method and hypsometer. 4. Volume measurement of logs using various formulae. 3 5. Nursery lay out, seed sowing, vegetative propagation techniques. 3 6. Forest and their management. 3 7. Visits of nearby forest based industries. 2 Total 18

Chapter 1 Introduction – definitions of basic terms related to forestry, objectives of silviculture, forest classification, salient features of Indian Forest Policies.

INTRODUCTION: Forestry is nature‘s greatest bounty to mankind. With the depletion and degradation of natural resources by over use we are still lagging far behind in the process of development through modernization. Availability of resources is generally much below the world average and far below the average of developed countries. The country do not have enough land space and the productivity of the available space as far as the are concerned is also very low. Forests in India cover about 22.8 %. Estimates of the area currently classified as forest land in India vary widely from as high as 75 million hectares to as low as less than 40 million hectares. This represents 23 and 12 per cent respectively total land area of the country (327.7 M.ha) of the total geographical area admeasuring 74.72 m.ha as against 33 1/3 % enunciated in the National forest policy 1988 to maintain the ecological balance of forest area in A.P. is 6.3 m.ha covering 23.2 % of the total geographical area (27.7 m.ha). as compared to the world average of 1.6 ha per capita forest area, India has 0.11 ha per capita forest area mainly due to the population increase. The country has lost about 43.4 m.ha of forest area during 1951-52 to 1982 – 83 @ 1.5 m.ha / annum, the main reasons being excessive biotic interference, removal of cut forest exceeding than the forests could produce, diversion of area for agriculture for river valley projects and industries etc. The productivity of Indian forest is also very low 0.5 m/ha when compared to the world average of 2 m/ha because of over exploitation, overgrazing and excess maltreatment of forest area in the past. In India most of the forests (95%) are owned and managed by the government in contrast to the management of forests by private sector in the European countries. Although forests occupy 22.8 % they are reported to contribute not much (1%) towards the national economy when compared to agriculture (35%), many reasons have been attributed to the low revenue. Removal of large amount of forest produce by the local population in the form of rights and concessions as well as illicit removals being the main ones. Yet another problem faced by the Indian forestry is the lack of proper investment in and programmes. (the investments never exceeded 0.75% of the total plan outlay in the public sector). During the five year plans large scale development and rehabilitation works were launched in the forestry. With the introduction of conservation and the work of demarcation of forest areas and working plan preparation was taken up. At present as a consequence the area covered under working plans constitutes about 66 % of total forest area.

Definitions of basic terms related to forestry:

Adaptive Management A type of forest land management in which, as an ongoing process, the monitoring of results of management decisions, in relation to sustaining ecosystem characteristics and changes in societal goals, is used to modify management approach. Advance Regeneration (Reproduction) syn. Advance Growth Seedlings or saplings that develop or are present in the understory. Afforestation: Establishing a forest by artificial means on an area on which not forest vegetation has existed for a long time in the past. Age Class (Cohort) A distinct aggregation of trees originating from a single natural event or regeneration activity, or a grouping of trees, e.g., 10-year age class, as used in inventory or management. Age classification: The division of a crop according to difference in age or the allotment of to age classes. Age crop: The age of a regular crop corresponding to its crop diameters. Agroforestry : Deals with the integration of crops, forest plants or livestock Alpine: Zone of vegetation where winter is server, slow fall heavy, the mean annual temperature is 450F and the mean January temperature below 300F. In India Himalayan at the altitude above 10,000 ft. and behavior of the soil upon which forest is to be established and behaviour of under varying conditions. Artificial Regeneration (Reproduction) An age class created by direct seeding or by planting seedlings or cuttings. Basal area: The area of the cross section of a stem at breast height, when applied to a crop, the sum of basal areas of all the stems or the total basal areas per unit area. Biological Diversity The variety and abundance of life forms, processes, functions, and structures including the relative complexity of species, communities, gene pools, and ecosystems at spatial scales that range from local through regional to global (syn. Biodiversity). Bole: The main stem of a tree. Breast height: Almost universally adopted as the standard height for measuring the girth, diameter and a basal areas of standing trees. India 4‘6‖ (1.37m). In U.K. and most commonwealth countries 4‘.3‖ (1.30m) Canopy The foliar cover in a forest stand consisting of one or several layers. Cleaning A release treatment made in an age class not past the sapling stage in order to free the favored trees from less desirable individuals of the same age class that overtop them or are likely to do so (see Improvement Cutting, Liberating, Weeding). with Reserves A clearcutting method in which varying numbers of reserve trees are not harvested to attain goals other than regeneration. Clearcutting A method of regenerating an even-aged stand in which a new age class develops in a fully exposed microclimate after removal, in a single cubing, of all trees in the previous stand. Regeneration is from natural seeding, direct seeding, planted seedlings, and/or advance reproduction. Cutting may be done in groups or patches (Group or Patch Clearcutting), or in strips (Strip Clearcutting). In the Clearcutting System, the management unit or stand in which regeneration, growth, and yield are regulated consists of the individual clearcut stand (see Group Selection). When the primary source of regeneration is advance reproduction, the preferred term is Overstory Removal. Codominant Trees with crowns forming the general level of the main canopy in even-aged stands or, in uneven-aged stands, the main canopy of the tree's immediate neighbors, receiving full light from above and comparatively little from the sides. Composition, Stand The proportion of each tree species in a stand expressed as a percentage of either the total number, basal area, or volume of all tree species in the stand. conversion and putting the forest produce for a variety of uses like timber, fuel, Coppice Methods Methods of regenerating a stand in which the majority of regeneration is from stump sprouts or root suckers. Coppice with Reserves A coppice method in which reserve trees are retained to attain goals other than regeneration. The method normally creates a two-aged stand. Coppice: When certain plants or seedling are cut from near ground level, they produce a flush of fresh shoots. This is known as coppicing Coupe: A area, usually one of an annual series unless otherwise stated. Preferable numbered with Roman numbers as, I, II, III etc. Crop Tree Any tree that is selected to become a component of a future commercial harvest. Crown Class A class of tree based on crown position relative to the crowns of adjacent trees. Crown Cover The ground area covered by the crowns of trees or woody vegetation as delimited by the vertical projection of crown perimeters and commonly expressed as a percent of total ground area (syn. Canopy Cover). Crown Density The amount and compactness of foliage of the crowns of trees and/or shrubs. Crown Thinning (Thinning from Above, High Thinning) The removal of trees from the dominant and codominant crown classes in order to favor the best trees of those same crown classes. Crown The part of a tree or woody plant bearing live branches and foliage. Cutting Cycle The planned interval between partial harvests in an uneven-aged stand (see Thinning Interval). : Refers to description, classification and recognition of tree Dendrology: The identification and systematic classification of trees. Dominant Trees with crowns extending above the general level of the main canopy of even- aged stands or, in uneven-aged stands, above the crowns of the tree's immediate neighbors, and receiving full light from above and partly from the sides. Ecological Approach A type of natural resource planning, management, or treatment that ensures consideration of the relationship between all organisms (including humans) and their environment. Ecological Classification A multifactor approach to categorizing and delineating, at different levels of resolution, areas of land and water having similar characteristic combinations of physical environment (such as topography, climate, geomorphic processes, geology, soil, and hydrology), biological communities (such as plants, animals, microorganisms, and/or potential natural communities), and human factors (such as social, economic, cultural, and infrastructure. Ecological Process A series of natural biological, physical, and social actions or events that link the growth and development of organisms (including humans) within their environments. economics to a forest estate for the production of certain desired results. Ecoregion A contiguous geographic area having similar macroclimate, possibly with several vegetation types, and used as an ecological basis for management or planning. Ecosystem Management The use of an ecological approach to resource management at the landscape level that blends social, physical, economic, and biological processes to ensure the sustainability of healthy ecosystems while providing desired values, goods, and services. Ecosystem A conceptual unit comprised of organisms interacting with each other and their environment having the major attributes of structure, function, complexity, interaction and interdependency, temporal change, and no inherent definition of spatial dimension. Emergent Trees with crowns completely above the general level of the main canopy receiving full light from above and from all sides. Even-aged Methods Methods to regenerate a stand with a single age class. Even-aged Stand A stand of trees containing a single age class in which the range of tree ages is usually less than 20 percent of rotation. Even-aged System A planned sequence of treatments designed to maintain and regenerate a stand with one age class. The range of tree ages is usually less than 20 percent of the rotation. (see Clearcutting, Seed Tree, Shelterwood, Coppice). Felling: Felling comprise of removal of trees either singly or in small groups scattered all over the forest. . Forest Fertilization The addition of nutrient elements to increase growth rate or overcome a nutrient deficiency in the soil. Forest Health A forest condition that has overall structure, function, and characteristics that enable it to be resilient to disturbance and to maintain normal rates of change commensurate with its stage of development. Forest Management : Is the practical application of science, technique and Forest mensuration : Deals with the measurement of forest produce. Forest policy and Administration : Deals with the rules, regulations, laws. Forest utilization : Branch of forestry dealing with the harvesting, marketing. Forest: The word forest is derived from Latin word ‗Foris‘ means outside. Therefore forests are areas covering practically all uncultivated and untended lands fairly extensive stretch of land covered with rather tall and dense tree growth. Forests are also defined as an area set aside for the production of timber and other forest produce and is under woody vegetation for certain benefits which it provides. Forestry soils : Refers to the composition, physical and chemical characters Forestry: Forestry has been defined as ‗the theory and practice of all that constitutes the creation, conservation and scientific management of forests and the utilization of their resources.forests and utilization of their products. It also stands for scientific management of forests Fragmentation The process, through cutting or natural processes, of reducing the size and connectivity of stands that compose a forest or landscape. Free Thinning The removal of trees to control stand spacing and favor desired trees using a combination of thinning criteria without regard to crown position. Genotype The genetic constitution of an organism in terms of its hereditary characteristics as distinguished from its physical appearance or phenotype. Green Tree Retention (see Reserve Trees) Group Selection with Reserves A variant of the Group Selection Method in which some trees within the group are not cut to attain goals other than regeneration within the group. Group Selection (see Regeneration Methods) Group Selection A method of regenerating uneven-aged stands in which trees are removed, and new age classes are established, in small groups. The maximum width of groups is approximately twice the height of the mature trees, with small openings providing microenvironment suitable for tolerant regeneration and the larger openings providing conditions suitable for more intolerant regeneration. In the Group Selection System, the management unit or stand in which regeneration, growth, and yield are regulated consists of a landscape containing an aggregation of groups. (see Clearcutting) Habitat Type An aggregation of units of land capable of producing similar plant communities at climax. Habitat The place where an animal or plant naturally or normally lives and develops. Harvesting Method A cutting by which a stand is logged. Emphasis is on meeting requirements while concurrently attaining silvicultural objectives. (see Regeneration Methods) Improvement Cutting A cutting made in a stand pole-sized or larger primarily to improve composition and quality by removing less desirable trees of any species. (see Cleaning, Liberating, and Weeding) Ingrowth Trees that during a specified period have grown past an arbitrary lower limit of (usually) diameter or height. Ingrowth is usually measured as basal area or volume per unit area. Intermediate Treatments (Tending) A collective term for any treatment designed to enhance growth, quality, vigor, and composition of the stand after establishment or regeneration and prior to final harvest. (see Tending, Stand Improvement) Intermediate Trees with crowns extending into the lower portion of the main canopy of even-aged stands or, in uneven-aged stands, into the lower portion of the canopy formed by the tree's immediate neighbors, but shorter in height than the codominants. They receive little direct light from above and none from the sides. Landscape A viewed area of land of generally large size and commonly a mosaic of land forms and plant communities irrespective of ownership or other artificial boundaries. Liberating A release treatment made in a stand not past the sapling stage in order to free the favored trees from competition of older, overtopping trees. Log: The stem of a tree or a length of stem or branch after felling and trimming. Logging: Operation comprising felling of trees, , bucking and transportation of the resulting product out of the forest timber harvesting (Bucking-Act of being) Lopping: It pertains to the cutting of branches or even young stems. This leads to the development of new shoots. It is carried out on Diospyros (Temburni) for bidi industry, also in number of broad leaved species for fuel and fodder and as Quercus incana (Indiana oak), morus etc, for rearing silkworm. Low Thinning (Thinning from Below) The removal of trees from the lower crown classes to favor those in the upper crown classes. Mechanical Thinning (Geometric Thinning) The thinning of trees in either even- or uneven-aged stands involving removal of trees in rows, strips, or by using fixed spacing intervals. Mixed Stand A stand in which there is a mixture of species. Monoculture A stand of a single species, generally even-aged. Mycorrhizae The symbiotic association between certain fungi and plant roots which enhances the uptake of water and nutrients. Natural Regeneration An age class created from natural seeding, sprouting, suckering, or layering. Nurse Tree (Nurse Crop) A tree, group or crop of trees, shrubs or other planes, either naturally occurring or introduced, used to nurture, improve survival or improve the form of a more desirable tree or crop when young by protecting it from frost, insolation, or wind. Old Growth Forest ecosystems distinguished by old trees and related structural features characteristic of later stages of stand and successional development. Some have large trees, snags, large down woody material, multiple tree canopy layers. Overstory Removal The cutting of trees comprising an upper canopy layer in order to release trees or other vegetation in an understory. (see Clearcutting) Overtopped (Suppressed) Trees of varying levels of vigor that have their crowns completely covered by the crowns of one or more neighboring trees. Phenotype The observed expression of a trait in an individual resulting firm developmental interaction of the individual's genotype and its operational environment. Pole: A young tree from the time when the lower branches begin to fall off to the time when rate of height growth begins to slow down and crown expansion becomes marked. Pollarding: This is a process in which the branch of a plant is cut off in order to produce a flush of new shoots. Pollarding is carried out at a height which is above the reach of browsing animals. It has been widely adopted on salix trees in Kashmir Valley. (Willow), Hardwickia binata in A.P. (Anjan), Grewia oppositifolia in U.P. Hills (Silver oak type) Precommercial Thinning (PCT) A thinning that does not yield trees of commercial value, usually designed to reduce stocking in order to concentrate growth on the more desirable trees. Pricking out: When the seedlings have to be kept in the nursery for more than a year, it must be transferred to beds, other than the seedling beds. This is known as pricking out or to transplant small seedlings individually in to nursery beds or boxes. Productivity A term describing the relative capacity of an area to sustain a supply of goods and/or services in the long run. Protected forests: A legal terms for an area subjected to limited degrees of protection under the provision of Chapter IV of the Indian Forest Act. : Means the cutting of branches from the bole in order to maintain the quality of timber, pulp wood etc. Pure Stand A stand composed of essentially a single species. Raft: An assemblage of logs, timbers or tied together or enclosed within a boom for transport by floating. Reforestation The natural or artificial restocking of an area with trees (syn. Regeneration). Reforestation: Re-establishing a forest, by artificial means on an area which previously bore forest vegetation, and which may have been felled or otherwise cleared in the recent past. Regeneration (Reproduction) Method A cutting method by which a new age class is created. The major methods are Clearcutting, Seed Tree, Shelterwood, Selection, and Coppice. (see Harvesting Method) Regeneration (Reproduction) Period The time between the initial regeneration cutting and the successful reestablishment of a new age class by natural means, planting, or direct seeding. Regeneration Seedlings or saplings existing in a stand; or the act of establishing young trees naturally or artificially (syn. Reforestation). Regular Uneven-aged (Balanced) Stand A stand in which three or more distinct age classes occupy approximately equal areas and provide a balanced distribution of diameter classes. Release (Release Operation) A treatment designed to free young trees from undesirable, usually overtopping, competing vegetation. Treatments include cleaning, liberating, and weeding. (see Stand Improvement) Reserve Trees (Green Tree Retention) Trees, pole-sized or larger, retained in either a dispersed or aggregated manner after the regeneration period under the Clearcutting, Seed Tree, Shelterwood, or Coppice Methods (syn. Standards). Reserved forests: an area so constituted under the Indian Forest Act or other Forests law. Resiliency The capacity of an ecosystem to maintain or regain normal development following disturbance. Root Pruning The root pruning of seedlings in a nursery bed to limit the extension of roots in depth or laterally. (see Undercutting) Rotation In even-aged systems, the period between regeneration establishment and final cutting. Salvage Cutting The removal of dead trees or trees being damaged or dying due to injurious agents other than competition, to recover value that would otherwise be lost. Sanitation Cutting The removal of trees to improve stand health by stopping or reducing actual or anticipated spread of insects and disease. (see Stand Improvement) Sapling A tree, usually young, that is larger than a seedling but smaller than a pole. Size varies by region. Scarification Mechanical removal of competing vegetation and/or interfering debris, or disturbance of the soil surface, designed to enhance reforestation. Scrub: Inferior growth consisting chiefly of small or stunted trees and shrubs. Seed orchards: are plantations which may raised exclusively with the aim of producing seed. Seed Production areas or seed stands: Which are area set aside exclusively for the purpose (i) to produce seed of high quality from genetically superior trees available in the stand (ii) to concentrate seed collecting operation in a small sphere or area. The seed stands are established by removal of the inferior frees, seed orchards are of genetically superior trees isolated to reduce pollination from genetically inferior once. Seeds orchards may be of two types: (i) Clonal: raised by grafting clones of superior trees on 2-3 year old seedlings (2) Seedling raised from obtained from seeds of superior trees. Seed Tree with Reserves A seed tree method in which some or all of the seed trees are retained after regeneration has become established to attain goals other than regeneration. Seed Tree An even-aged regeneration method in which a new age class develops from seeds that germinate in fully exposed microenvironments after removal of all the previous stand except a small number of trees left to provide seed. Seed trees are removed after regeneration is established. Selection Thinning (Dominant Thinning) The removal of trees in the dominant crown class in order to favor the lower crown classes. Shelter belts: is a wide zone of trees, shrubs and grasses, planted in rows, usually at right angles to the direction of the prevailing winds. Shelterwood with Reserves A variant of the Shelterwood Method in which some or all of the shelter trees are retained, well beyond the normal period of retention, to attain goals other than regeneration. Shelterwood A method of regenerating an even-aged stand in which a new age class develops beneath the moderated microenvironment provided by the residual trees. The sequence of treatments can include three distinct types of cuttings: (1) an optional preparatory cut to enhance conditions for seed production; (2) an establishment cut to prepare the seed bed and to create a new age class; and (3) a removal cut to release established regeneration from competition with the overwood. Cutting may be done uniformly throughout the stand (Uniform Shelterwood), in groups or patches (Group Shelterwood), or in strips (Strip Shelterwood). Silvicultural System A planned process whereby a stand is tended, harvested, and reestablished. The system name is based on the number of age classes (see Even-aged, Two- aged, Uneven-aged), and/or the regeneration method used (see Clearcutting, Seed Tree, Shelterwood, Selection, Coppice, Coppice with Reserves). Silviculture: The terms silviculture, commonly refers only to certain aspects of theory and practice of raising forests crops or Silviculture pertains to the establishment, development, are and reproduction of forests crops. Single Tree Selection A method of creating new age classes in uneven-aged stands in which individual trees of all size classes are removed more-or-less uniformly throughout the stand to achieve desired stand structural characteristics. Site Class A classification of site quality, usually expressed in terms of ranges of dominant tree height at a given age or potential mean annual increment at culmination. A measure of actual or potential forest productivity expressed in terms of the average height of a certain number of dominants and codominants in the stand at an index age. Site Preparation A hand or mechanized manipulation of a site designed to enhance the success of regeneration. Treatments may include bedding, burning, chemical spraying, chopping, disking, drainage, raking, and scarifying. All treatments are designed to modify the soil, litter, and vegetation and to create microclimate conditions conducive to the establishment and growth of desired species. Site Quality (Productivity) The productive capacity of a site, usually expressed as volume production of a given species. Size Class Tree size recognized by distinct ranges, usually of diameter or height. A standing dead tree from which the leaves and most of the branches have fallen. species. Stand Density A quantitative, absolute measure of tree occupancy per unit of land area in such terms as numbers of trees, basal area, or volume. Stand Improvement A term comprising all intermediate cuttings made to improve the composition, structure, condition, health, and growth of even- or uneven-aged stands. Stand: An aggregation of trees or other growth possessing sufficient uniformity in composition, constitution, age arrangement or condition, to be distinguished from adjacent crops and forming a silvicultural unit. Stewardship Caring for land and associated resources in a manner that enables their passing on to future generations in a healthy condition. Stocking An indication of growing-space occupancy relative to a preestablished standard. Common indices of stocking are based on percent occupancy, basal area, relative density, and crown competition factor. Stratified Mixture A stand in which different species occupy different strata of the total crown canopy. Stratum (Canopy Layer) A distinct layer of vegetation within a forest community. Structure The horizontal and vertical distribution of components of a forest stand including the height, diameter, crown layers and stems of trees, shrubs, herbaceous understory, snags, and down woody debris. Succession A series of dynamic changes by which Organisms succeed one another through a series of plant community (seral) stages leading to potential natural community or climax. Succession: The gradual replacement of one community by another in the development of vegetation towards a climax Suppressed (see Crown Class) Sustainability The capacity of forests, ranging from stands to ecoregions, to maintain their health, productivity, diversity, and overall integrity, in the long run, in the context of human activity and use. Taungya system: It was first evolved in Burma in 1850 as a mode of replanting vast areas. Taungya is a Burmas word. (Toung hill, ya - cultivation). This is a modified from of shifting cultivation of which the labour has permission to raise crop on the land, but, with this, they are responsible for planting, of the forest species, also for protection and well being of the plantation. After about five years or so, they are required to move to another patch of land. Tending: Tending is a board terms given to operation which are carried out for the well being of forest crops, at any stage of it life, involving operation both on the crop itself and on its competing vegetation e.g. weeding, cleaning, thinning, improvement feeling etc. However, tending does not include operation concerning, regeneration such as regeneration feeling, soil working, control burning etc. Thinning Interval The period between successive thinning envies, usually used in connection with even-aged stands. (see Cutting Cycle) Thinning A cultural treatment made to reduce stand density of trees primarily to improve growth, enhance forest health, or to recover potential mortality. a. To deflect the air current. b. To protect the leeward area from the desiccating effects of hot winds. c. To provide general protection d. To reduce the velocity of prevailing winds Tolerance Shade The relative capacity of a plant to become established and grow beneath overtopping vegetation. Two-aged Methods Methods designed to maintain and regenerate a stand with two age classes. In each case the resulting stand may be two-aged or tend toward an uneven-aged condition as a consequence of both an extended period of regeneration establishment and the retention of reserve trees that may represent one or more age classes. Two-aged Stand A stand composed of two distinct age classes separated in age by more than 20 percent of rotation. Two-aged System A planned sequence of treatments designed to maintain andregenerate a stand with two age classes. Unclassed forest: Forest land owned by Government but not constituted in to a reserved, village or protected forest. Undercutting The root pruning of seedlings in a nursery bed to limit root depth extension. (see Root Pruning) Uneven-aged (Selection) Methods Methods of regenerating a forest stand, and maintaining an uneven-aged structure, by removing some trees in all size classes either singly, in small groups, or in steps. Uneven-aged Stand A stand of trees of three or more distinct age classes, either intimately mixed or in small groups. Uneven-aged System A planned sequence of treatments designed to maintain and regenerate a stand with three or more age classes. (see Single Tree Selection, Group Selection) Watershed An area of land with a single drainage network. Weeding A release treatment in stands not past the sapling stage that eliminates or suppresses undesirable vegetation regardless of crown position. Wind breaks: Is a protective plantation in a certain area, against strong winds. It is usually comprised of a few rows of trees (or shrubs) spaces at 0.5 to 2.5 m apart.) Wood technology : Deals with the structure, physical, mechanical properties Wrenching The disturbance of seedling roots in a nursery bed (e.g., with a tractor-drawn blade) with the objective of stimulating the development of a fibrous root system.

Objectives of Silviculture: Silviculture is improved limitation of nature. In nature, we find a large number of species coming up at one place. Some individuals die out of competition, some attain top canopy while others remain at lower levels. Silvicultural factors are usually controlled by economic considerations. If there are a large number of species, perhaps a would select some of them which are economically more important. Also the forester may remove the trees which are likely to die out of suppression. Since our knowledge of economic and natural factor is not perfect, it is not always possible to determine how far to divert from purely natural course. In nature, succession is a process in which one species or group of species is replaced by another species or group of species and a stage comes when more stable species appears. The study of silviculture enables the to know the whole course of natural succession on a given site and also the manner and the speed of existing crop being replaced or altered. This knowledge helps the foresters to determine where and how to control the succession. The important objectives of silviculture can be summarised as under:

1. Control of Crop Composition and Production of Species of More Economic Value: Under natural conditions, a large number of species form the crop inferior or less valuable species may flourish at the expense of the desirable species. The control is exercised by two ways: i. By removing or cutting inferior species ii. By creating more favourable conditions for the regeneration and growth of desirable species. 2. Control of Stand Density, for Production of Maximum Volume: In the natural forests, trees are likely to grow either too dense or too open. If the trees are too dense-the is distributed over large number individuals and none of them grow to the optimum size. If the trees are too less, the production would be less, though individual trees may grow sufficiently with higher dimensions. If the trees are too less, they will not be able to utilise the site, effectively and may be even inadequate to regenerate the area. Both these conditions are not good for maximum wood production. Silviculture helps to maintain or retain sufficient number of trees per unit area so that by optimum use of soil, maximum wood production is ensured. Substantial increase in production can be ensured by thinning dense prop through salvaging the trees otherwise these trees would have died. 3. Afforestation of Blank and Under Stocked Areas: There is a large area of forests which is blank or under stocked due to fire, encroachments, illicit fillings, or some natural causes. These areas are however, suitable to bear tree growth. Silviculture helps us to afforest these areas with suitable trees by planting or by seedling. Silviculture guides to know the best period of seed collection, nursery technique, plantation details, etc. to complete afforestation. 4. Production of Quality Timber: In unmanaged forests, because of intense competition or little competition, quality timber is not produced. A large number of trees are malformed, defective and sometimes diseased. Proper control of damaging agencies can increase the production. Insects,fungi,fire,wind, grazing,lopping, etc. which affect the quality of the timber are controlled by suitable silvicultural techniques and methods. 5. Control on Rotation Period: Rotation is counted period in years from regeneration to harvesting. In unmanaged forests, if there are more number of trees, the growth of individual tree is slow consequently, they take longer period to reach to harvestable size. The knowledge of silviculture helps to regulate the density of the crop at various sizes / ages which helps to reach exploitable size much faster. Thus, rotation of a crop can be reduced by regulating the density of the crop. It also helps in identifying short rotation crops. 6. Facilitate Management and Use of Forests: In unmanaged forests, good forests exist in difficult areas, where it is difficult to manage and harvest the timber. In managed forests, it is easy to plant the growth and distribution of forests so that the produce is used efficiency and economically. It is possible to arrange the forest in different localities in such age classes and species composition that management becomes easy. 7. Creation of Man Made Forests and Introduction of Exotics: Silvicultural techniques help us to replace wholly or partly, natural forests by man mad forests of the same species or by other species. If the existing, forest does not contain valuable and the desirable species. It can be planted with such important species. If the forest consists of desirable species but it is not regenerating properly, it can be harvested and regenerated artificially. Identification of suitable exotics depending upon geographical location, raising trail, plantations, selection of suitable exotics species, perfecting the nursery and plantation techniques of the exotics are some of the silvicultural techniques which help in introduction of exotic species on a large scale. 8. Protection of Site and Intangible Returns: The main object of silviculture is to provide maximum protection to the site so that intangible returns from the forests are ensured. Important intangible returns include, moderating climate, increasing precipitation, reducing soil erosion and floods conserving soil and water increasing water yields providing shelter to a large number of wild animals, etc. Silviculture helps to understand the requirement of a tree and its effect on the site. The species, which are likely to deteriorate the site, are discarded. Only such species which afford complete protection to the site and ensure continuous flow of intangible benefits are preferred. Study of silviculture helps to attain the following objects : 1. To derive environmental benefits. 2. Raising species of more economic value. 3. Production of high quality timber 4. Production of more volume per unit area. 5. Reduction of rotation period. 6. Afforestation of blank areas. 7. Creation of plantations. 8. Introduction of exotics. 9. Employment potential 10. Increase in the production of fuel and fodder. 11. Development of forest industries. Classification of Forests Forests can be classified on the basis of: 1.Age, 2.Method of regeneration, 3. Composition, 4. Ownership, 5. Object of Management, 6. Growing Stock. 1. Classification of Forest On the Basis of Age: Forest is classified into: A) Even Aged Forest: Even-aged forests, also called regular forests are those consisting of even - aged woods. Even - aged wood means trees of approximately the same age. True even - aged forests can be only man - made forests. In case of forests, which regenerate naturally, some age difference is often allowed. Differences up to 25% of the rotation are usually allowed in cases where forest is not harvested for 100 years or more. B) Un-Even Aged Forests: A forest is called uneven - aged or irregular when trees vary widely in age. 2. Classification of Forest On the Basis of Regeneration: Forests are identified into A. : When regeneration is obtained from seed B. Coppice Forest: When regeneration is through coppice or some vegetative part of the tree. 1. Natural Forest: When the regeneration is obtained naturally, the forests are called natural forests 2.Man Made Forest: When it is obtained artificially, the forests are called Man-made forests or Plantations. 3. Classification of Forest On the Basis of Composition: Forests are classified into A. Pure Forests: Pure forests are composed almost entirely ofo ne species, usually to the extent of not less than 50 pe cent. B. Mixed Forests: Mixed forests are defined as forest composed of trees of two or more species intermingled in the same canopy. 4. Classification of Forest On the Basis of Management: Forests are classified into A. Protection Forests: Protection forests are those which are managed primarily for ameliorating climate, checking soil erosion and floods, conserving soil and water, regulating stream flow and increasing water yields and exerting other beneficial influences. B. Production Forests: Production forests are those which are managed primarily for their produce. C. Social Forests: Social forests where the produce is utilised by neighbouring society. 5. Classification of Forest On the Basis of Ownership: Forests can be classified as A. Government Forests: On the basis of Legal status, Government forests are further classified into: a. Reserved Forests: A Reserved forest is an area with complete protection, constituted according to chapter II of the Indian Forests Act. 1927. b. Protected Forests: A Protected forest is an area subject to limited degree of protection constituted under the provisions of chapter IV of the Indian Forest Act., 1927. c. Village Forests: A Village forest is a state forest assigned to a village community under the provisions of chapter III of Indian Forest Act. B. Private Forests C. Forests owned by Corporations, Panchayats, Societies and other Agencies. 6. Classification of Forest On the Basis of Growing Stock: A forest can be classified into A. Normal Forest: A Normal forest is an ideal forest with regard to growing stock, age class distribution and increment and from which the annual or periodic removal of produce equals to the increment and can be continued indefinitely without endangering future yields. B. Abnormal Forest: Abnormal forest is one which is not normal, i.e. growing stock, age, class, distribution of stems, increment, etc. are either in excess or more usually in dificit than the normal forest.

Salient features of Indian forest policies: Although the forest management in India has been on a sound footing since 1864, the condition of the forests continued to deteriorate through over exploitation. Efforts were made to conserve the forest resources. The first effort in this direction was made by enunciating the first forest policy of India on 19th October 1894. The important features of this policy were : 1. The state forests are to be administered for the benefit of the public. 2. Forests on hill slopes may be protected. 3. The requirements of people may be met from second class state forest. 4. Whenever an effective demand for cultivable land exists, the needed land can only be supplied from the forest area without habitation. 5. Royalty for the government must be collected for various facilities enjoyed by people. The main aim of the forest policy of 1894 was to collect revenue from the forests and please the local population by granting them rights and concessions. There was no intention to improve the forestry management in general. After independence the Government of India, Ministry of Agriculture enunciated the second National Forest Policy on 12th May 1952. It has been formulated on the basis of 6 paramount needs of the country. 1. The need of evolving a balanced and complimentary land use so that each land allotted should produce most and deteriorate least. 2. The need for checking :- a) Denudation in mountain regions on which depends the perennial water supply of the river system. b) The erosion progressing place along the treeless bank areas of rivers and on vast stretches of undulating wastelands leading to ravine formations. C) Invasions of seasand on coastal tracts and shifting sand dunes. 3. The need for establishing tree lands wherever possible for the amelioration of physical and climatic conditions promoting the general well being of the people. 4. The need for insuring progressively increasing supplies of grazing small wood for agriculture implements and in particulars of fire wood to release the cow dung as a manure. 5. The need for sustained supply of timber and other forest produce required for defense, industry etc. 6. The need for the realization of the maximum annual revenue in perpetuity consistent with the fulfillment of the enumerated above. This forest policy recommends that India should aim at maintaining the 1/3 rd of its land area under forest. But this policy mainly aims at conservation forestry and there is no emphasis on production forestry. Therefore to make the existing forest with their low productivity should be converted into plantation forestry of high productivity which is possible only through enunciation of new forest policy of 1988, which has been announced in the parliament by the Minister of Environment, Government of India on 7th December 1988. The main objectives of New National Forest Policy are: 1. The national goal should be to have 1/3 rd of the total land area of the country under forest to save fragile ecosystems. 2. The forest should not be looked upon as a source of revenue. Forests that clothe steep slopes, catchments of rivers, lakes, reservoirs should be protected and checking extension of sand dunes. 3. Massive need based and time bound programme of afforestation and with a particular emphasis on fuel wood and fodder development on all degraded lands in the country are to be promoted whether forests or non-forests as a national imperative. 4. The policy emphatically says that construction of dams, reservoirs, mining and expansion of agriculture should be consistent with the needs for conservation of trees and forests. The policy categorically states that no mining lease should be granted to any party (Private or public). 5. The policy specifies that land laws should be modified wherever necessary as to facilitate or motivate individuals and institutions to undertake tree farming or grow fodder trees, grasses and legumes on their own land. 6. The policy favours the restrictions on grazing, browsing in forest areas by levying grazing fee to discourage people in forests area from raising large heards of essential livestock. 7. The policy envisages to put an end to removal of timber by contractors by replacing bodies like tribal and labour cooperatives and Governments corporations. 8. The new forest policy also invites a special care for the needs of wild life conservation.

Chapter 2 Forest regeneration, natural regeneration- natural regeneration from seed and vegetative parts, coppicing, pollarding, root suckers. Forest regeneration: Forest regeneration is the act of renewing tree cover by establishing young trees naturally or artificially generally, promptly after the previous stand or forest has been removed. The method, species, and density are chosen to meet the goal of landowner. Forest regeneration includes practices such as changes in tree plant density through human assisted natural regeneration, enrichment planting, reduced grazing of forested savannas, and changes in tree provenences/genetics or tree species. human assisted natural regeneration means establishment of a forest age class from natural seeding or sprouting after harvesting through , shelter (or seed tree) harvest, soil preparation, or restricting the size of a clear-cut stand to secure natural regeneration from surrounding trees. Enrichment planting means increasing the plant density (i.e., the number of plants per hectare) in an already growing forest stand. Our forests here in the Northeast are very resilient. When they are disturbed by cutting, fire, storm, infestation or disease, they bounce back rapidly. Existing seedlings (called advance regeneration) will take advantage of the increased light, water and nutrients. Others will grow from the damaged trees' stumps and roots. More seedlings will develop from seeds stored in the leaf duff on the forest floor, and from seed that blows in from nearby trees. Yet other seeds will be carried into disturbed areas by birds and animals. Different tree species have developed different regeneration strategies over millions of years of evolution. Some trees produce many, small seeds and depend upon the wind for their dispersal. Other trees produce a few, large seeds and depend upon animals for their dispersal. Some tree seeds need little light or heat in order to germination; others need much heat and light. Some sprout from stumps and roots; others do not. If there are seedlings of desirable species already established when a forest is cut or otherwise disturbed, a new, high quality forest can develop immediately. Many of our best timber stands developed in this way after heavy cutting in the past. For whatever reasons, conditions were right for germination and growth of those seedlings and sprouts before the overstories were harvested. Unfortunately however, the opposite is more often the case. Desirable seedlings were not there before the last harvest; the right kinds of seeds didn't blow in or get carried in, and they didn't sprout from stumps and roots. The same usually happened when old pastures or fields were abandoned. Good quality seed sources weren't available, or if they were, the seeds didn't germinate and grow. When forests are repeatedly high-graded, that is, when the best trees are cut and the rest are left to grow, the results are forests dominated by low-grade species, poor quality trees of grade species, and cull trees of all species. Such forests would probably have been better off if they had been clearcut because then at least the poor quality trees would have been removed. In order to control and optimize regeneration, foresters have developed silvicultural systems to regenerate forests of different species mixes and ages. These systems are designed around the regeneration strategies of the desired species. They involve manipulation (cutting) of forest stands to influence the seed mix and light/heat conditions on the ground. Sometimes they also involve manipulation of existing (advance) regeneration and treatment of the seed bed (forest floor). There has been much discussion and debate among foresters and forest scientists about the relative merits of even-aged and uneven-aged silvicultural systems. Even-aged systems try to develop the next forest of seedlings by one or two partial overstory cuts, and then remove the rest of the overstory in a final cut. Uneven-aged systems periodically remove part of the overstory, but never all of it. Even-aged systems are recommended for use with shade-intolerant species such as oak, cherry and pine, and are described as shelterwood systems. The first one or two cuts leave good seed trees and the right amount of light on the ground for their regeneration. The final result is an even-aged stand of seedlings that grows rapidly into a new stand. Uneven-aged systems are recommended for shade-tolerant species such as sugar maple, beech and hemlock, and are described as selection systems. Ideally, these systems have a broad range of ages and sizes. In reality, they will usually have several age classes determined by the frequency of cutting in the stands. There are two main strategies of forest regeneration: • Natural regeneration • Artificial regeneration

Natural regeneration is making use of the natural regeneration potential of standing mature trees, thus entirely relying on natural seed sources or sprouting and little human intervention (e.g., seedbed preparation, selection). In contrast, artificial regeneration relies on the active introduction of pre-selected seed or plant material to a forest site. General prerequisites of forest regeneration are: • Ensuring favourable site conditions for the target species (e.g., moisture, nutrient supply) • Ensuring adequate light regime In addition, a number of optional management interventions may be required depending on the respective site conditions: • Seedbed preparation (e.g., scarification) • Vegetation control (e.g., herbicide) • Game control (e.g., fencing) • Pest control (e.g., repellents) Natural regeneration Natural regeneration is defined as ‗the renewal of a forest crop by self-sown seed or by coppice of root suckers. To regenerate means ‗to renew a forest crop by natural or artificial means‘. Thus, regeneration (syn. Reproduction) is defined as ‗the renewal of a forest crop by natural or artificial means‘. In addition to the general prerequisites of establishing forest regeneration, the use of natural regeneration requires the presence of a seed source in or near the area to be regenerated. Seed sources should be healthy mature individuals of the target tree species featuring desirable properties. Natural regeneration can be established using various methods. All continuous cover silvicultural systems (e.g., shelterwood, selection) generally rely on establishment of natural regeneration. Other methods include seed tree retention cutting, small-scale clearcutting with seed trees in the vicinity, or coppicing. The establishment of natural regeneration is particularly recommendable for sites with a high risk of erosion, in protected areas, and for seed stands. Importance  Species always are well adapted to the localities  Multi-purposes species are grown naturally  Better conservation of biodiversities and amelioration of ecosystems  Meeting requirements of people and their domestic animals  Better wildlife habitats  More suited to conservation of soil and improvement of watersheds  Seedlings found have already be naturally hardened-off  Injurious or damaging species are found suppressed by natural pests or plants  Nursery grown seedlings are not necessary  Low cost and more net financial returns  Special Supervision of any kinds are not necessary  Vigorous growth of trees of favored species Factors affecting natural regeneration Factors affecting natural regeneration are given as follows: 1. Climatic Factors  Solar Radiation and Light  Precipitation  Local Temperature  Humidity (Atmospheric Moisture)  Frost  Snow Fall  Evapo-transpiration 2. Soil Factors  Organic matter and nutrient status  Soil structure and texture  Soil Temperature  Chemical Properties of Soil  Biological Properties of Soil  Erosion and Floods 3. Biological Factors  Man and his activities  Wild life and domestic animals  Diseases and Pests  Heavy growth of grasses and weeds  Forest fires Factors affecting natural regeneration by coppice: 1. Species- coppicing power 2. Age of tree-pole and young trees 3. Season of coppicing- before spring 4. Height of stump-15 to 25 cm. 5. Rotation-short 6. Silvicultural system- clear felling. Steps of natural regeneration 1. Selecting the seed trees. Before the site is logged, seed trees must be selected and marked with paint. Selection means choosing the best-looking trees for seed trees -- trees which are the straightest and tallest and have large crowns and no disease. The number to leave on the site will vary according to species. More seed trees are required for longleaf pine because it is not a prolific seed producer and its large seeds are often eaten by animals. Trees should be well-spaced over the site to allow even distribution of seed. 2. Planning for a good seed crop. The frequency of good seed crops varies from year to year and species to species. To insure successful natural regeneration, the site should be logged just prior to a good seed crop. You can observe the seed crop by looking through binoculars in the spring or early summer and counting cones to determine the crop for the fall or looking at conelets to predict next year's crop. Conelets resemble small pink or light green cones and are located near the ends of the branches; cones are green and are located further in on the branches. Both conelets and cones are in the top 2/3 of the tree crown. 3. Logging. The landowner should supervise the logging operation especially to insure that the seed trees are not damaged by the logging. Damaged trees may die or not produce a good seed crop. 4. Preparing the site. The site must be prepared to first incorporate the forest litter (organic matter) and then expose mineral soil -- seeds need soil to germinate and grow. Some site preparation options are to burn, mechanically scarify, and/or spray with herbicides. The soil needs to be exposed prior to October, when most seeds fall from the trees. Sometimes the logging operation is enough of a disturbance to expose the soil. However, the completeness and intensity of the site preparation may improve seedling establishment especially during periods of poor seed crop or drought. 5. Logging the remaining trees. When an adequate seedling stand is established and about 1-2 years old, the seed trees should be harvested. If you wait too long, seed trees may affect the growth of the seedlings and logging may damage the seedlings. For Longleaf pine the seed trees may be left. 6. Controlling unwanted vegetation. Shrubs, small trees, and herbaceous vegetation will compete with small seedlings for nutrients, water, and sunlight causing mortality or slower growth. For the first few years, the planting site should be observed to see if this unwanted vegetation is affecting seedling growth and survival and measures should be taken to control the weeds. Chemical control, hand-cutting, and mowing are three possible methods of control. Methods of natural regeneration A. Natural regeneration from seed When regeneration obtained from seed forms a crop, it is called a seedling crop. It is neither planted nor of coppice or root-sucker origin but originating in situ from natural regeneration. When this seedling crop grows into a forest, it is called a high forest. NR from seed depends on the followings: 1. Seed Production: The most important consideration for natural regeneration from seed is the production of adequate amount of fertile seeds by the trees of the area or in the vicinity. The production of seed depends on the following: species, age of trees, size of crown, climate, and other external factors. 2. Seed Dispersal: The seed produced by the trees is dispersed by the agency of wind, water, gravity, birds and animals. Some examples of seed dispersal by various agencies are given below:  Wind: Conifers, Acer, Betula, Populus, Alnus , Salix, Terminalia, Dalbergia, Acacia , Adina , Bombax, etc.  Water: Most mangrove species, Dalbergia, Teak, etc.  Birds: Prunus, Mulberry, Diospyrus, etc.  Animals: Acaica arabica, Prosopssis juliflora, Zizyphus, Anthocephallus, etc.  Gravity: Oak, Juglans, Asculus, etc. 3. Seed Germination: After dispersal, insects, birds and rodents destroy a lot of seeds. The others germinate provided they are deposited on suitable soil. Germination of seeds depends upon several internal and external factors listed below:  Internal Factors: Permeability to water, permeability to O2, development of embryo ( i.e., Fraxinus floribunda takes one year), after ripening (i.e., Juniperus macropoda), viability of seeds, size of seeds, germination capacity, germination energy  External factors: Moisture, air, temperature, light (i.e., Cassia fistula or Albizzia procera requires light), seed Bed. 4. Seedling Establishment: Even if germination is good, it does not mean that natural regeneration would be good because a large number of seedlings die at the end of rains or as a result of frost during winter or drought during summer. In addition, there may be other factors such as weeds, grazing, fire, which may kill the seedlings. Thus, establishment is defined as the development of new crop ‗naturally or assisted‘ to a stage when the young regeneration ‗natural or artificial‘ is considered safe from normal adverse influences and no longer needs special protection or tending operation other than cleaning, thinning and pruning. The following factors affect establishment of seedlings:  Development of roots  Soil conditions – Moisture, Aeration, Nutrients  Light  Other Climatic Factors- high or low temp.  Rainfall  Drip (Slash erosion)  Condition of grasses and other competing weeds  Grazing, Browsing and Fire  Composition of the crop B. Natural regeneration from vegetative parts When regeneration obtained by coppice forms a crop, it is called coppice crop and when it develops into a forest, it is called coppice forest to differentiate it from the high forest. Natural regeneration by coppice can be obtained either by: 1. Seedling coppice: Coppice shoots arising from the base of seedlings that have been cut or burnt back. This method of obtaining natural regeneration is used for cutting back woody shoots and established reproduction which is not making any progress so that they may produce vigorous shoots and soon develop into saplings. 2. Stool coppice: Coppice arising from the stool or a living stump of a tree is called stool coppice. In this method, regeneration is obtained from the shoots arising from the adventitious buds of the stump of felled trees. The coppice shoots generally arise either from near the base of the stump or from its top. The shoots arising from near the top of the stump are liable to be damaged by the rotting of the upper portion of the stump as well as by wind, etc. Vegetative reproduction can be obtained by any of the following methods: 1. Coppice: Vegetative reproduction in which the tree, plants or the seedlings of a species when cut near the ground level produce shoots. 2. Root Sucker (A shoot rising from the root of a woody plant): Vegetative reproduction in which a root of a plant is partially or wholly cut to produce a shoot called root sucker. 3. Cutting: Vegetative propagation in which a portion of the stem, branch or root is placed in the soil or other medium, in order that it may develop into a plant. Depending on the part of the plant used, cuttings may be classified into stem cutting, branch cutting, root cutting and root and shoot cutting. Root and shoot cutting is a young plant with pruned taproot and severed stem used for planting. 4. Layering: Inducing development of roots on branches while they are still attached to the trees is called layering. Layering may be done in soil or in air and so layering is of two kinds: air Layering and soil Layering 5. Grafting: Vegetative propagation in which a portion called scion (any unrooted portion of a plant used for grafting or budding on a rooted stock), of one plant is applied to stock (a rooted plant on which a scion is grafted), usually rooted, which is another plant, with the object of securing vegetative union between the two, when the scion is detached from the parent plant and the shoot of the other plant is severed, to produce a new plant to be planted out. Attempt is made to transport the scions to the grafting place within 24 hours. 6. Budding: A vegetative reproduction in which, a bud with some portion of the bark of a genetically superior plant is grafted on an inferior plant so that it can produce shoot when the old shoot of the stock is cut off. Bud is grafted on the stock in the form of a patch after removing the bark of the stock in that portion or by making an incision in the bark of the stock in the form of T and then fixing the scion inside it. Advantages of natural regeneration • Preservation of locally adapted populations • Preservation of high genetic variability • Good adaptation to micro-sites • Undisturbed root development • Mostly low cost • Low investment risk Disadvantages of natural regeneration • Inability to change genetic stock • Irregular regeneration density and tree species composition • Dependence on fructification and seed production • Low flexibility • High management intensity and complexity • Long risk period

Coppicing Many species of trees and shrubs have the ability to resprout after the whole tree has been cut. If this ability is utilized for regeneration of the tree the practice is known as coppicing. Coppicing can almost be regarded as a method of tree propagation since it can substitute for the task of planting a new tree after a mature one is felled.

Fig. Coppicing in alley cropping

Systematic coppicing is applied as the management technique in alley cropping, and it may be an option for trees on soil-conservation structures. In such a situation coppicing may be done annually, but in other situations, e.g. regeneration of Eucalyptus for pole production, it may be much less frequent. In that case, an interval of 6-8 years may be more suitable. Not all tree species will coppice after being cut. Some commonly coppiced species are: • Cassia siamea • Eucalyptus spp. • Leucaena leucocephala Certain species coppice well when young but may not do so if cut at maturity. Examples are Casuarina spp., Grevillea robusta, Sesbania sesban and some Albizia spp.

THE TREE COMPONENT

Fig. Some species only coppice well when young

Fig. A homestead with a stand that has been coppiced

Pollarding If all the branches and the top part of a tree are cut off this is known as pollarding. There can be several objectives with pollarding: • Early harvest of wood, fodder or other • Production of wood or fodder that is out of the reach of livestock, hence there is no need for protection from browsing • Reduction of shade for crops near by • Regeneration of the tree crown to promote growth of the trunk for timber or poles.

The choice of pollarding height and frequency depends on the desired products. If the main aim is production of timber or poles, the top of the tree should be cut as high up as possible, and the pollarding interval should be such that the crown is kept as green and vigorous as possible for the maximum production of trunk wood. An interval of 2-5 years is appropriate in such cases.

Fig. Pollarding

On the other hand, if the main aim is production of fuelwood or fodder, it is better to pollard lower down the tree to facilitate access. Pollarding can then be done more frequently, e.g. once a year. It is advantageous to try to form a wide "stool" (the part of the tree remaining at the base when it has been cut) in order to achieve a substantial production of biomass. Sometimes the main aim is to produce staking material, poles or fito for construction. In such situations a wide stool will allow many stems to grow. Initially too dense a stand may sprout after pollarding, and thinning is then recommended, leaving a suitable number of branches in relation to the size of the stems eventually desired. Not all species can withstand pollarding. Some commonly pollarded species are: • Casnarina spp. • Croton spp. THE TREE COMPONENT • Faidherbia (Acacia) albida • Grevillea robusta • Morus alba. Five important reasons for pollarding trees: • To get biomass for manure • To obtain fuel wood • To get poles for farm construction and building • To minimize shading on crops • For Grevillea: to enhance the growth of the bole for more timber.

Grevillea is normally pollarded high up to maintain a long stem for timber and pole production. The pollarding height is determined by the performance of the tree. If there are many branches or some type of deformity at a certain height that height may be chosen for cutting off the top. Consideration is also given to how many pieces of timber of standard lengths can be harvested later on. For other trees, pollarding is usually much lower and more haphazard. The main aim in pollarding other species of trees is to produce more biomass, leaves or poles at a height at which crop shading is minimized and harvest is easy. The production of leaves is more important than the production of poles. After pollarding, the wood is separated from the leaves. The wood is used for fuel, stakes for tomatoes, poles for fencing or house or cattleshed construction, and the leaves are thrown into the zero-grazing unit to serve as a bed for the cattle and to obtain more compost from the manure. Leaves are also used as mulch on tomato and potato plots where they greatly reduce weed growth. The pollarding interval depends on the product needed. For firewood andmulch, pollarding can be done once a year, but for poles it is done only every second year.Grevillea is a very good tree because it grows fast, gives good timber and can be pollarded to reduce shading on crops.

Root suckers:

Root sucker is a shoot rising from the root of a woody plant. It is that method of vegetative reproduction in which a root of a plant is partially or wholly cut to produce a shoot called root sucker. Natural regeneration by root suckers is not being attempted on any large scale anywhere in this country. This method used to be followed, sometimes, on the canal bank plantations in India and the chief species in which this was affected was sissoo. Where this method was followed, it was usual to dig continuous or discontinuous circular trenches with diameter of about 6 m round the isolated trees so that their roots may be severed and root suckers produced, which, with tending, could be developed into trees. The trees produced in this way are liable to wind-throw and poor in growth and therefore this method is not being favoured now. Diospyros root suckers are sometimes encouraged because the root suckers produce best biri leaves. Tree suckers are small tree sprouts that grow upward from tree root systems. Suckers have their own roots that make them a simple and fast method of propagation. The single sprouts produce a tree when removed from where they are growing and transplanted properly in a new location. Propagating suckers works best on trees that do not have a grafted root system so you know the tree sucker is the same variety as the main tree.

1. Inspect the tree and sucker growth to find suckers that are away from the main trunk for easier removal. Choose suckers that will cause the least amount of damage to the tree when removing. 2. Dig 4 to 6 inches around the sucker with a small spade carefully until you reach the main root from the tree. Clip the sucker roots with a sharp pruning clipper to remove the sucker from the tree. ensure there are roots extending from the base of the section you remove. Lift the sucker from the ground with as much soil around the roots as possible for protection. 3. Set the sucker on a clean tarp and moisten the soil and roots with water to prevent moisture loss. 4. Select a planting area with the same amount of sunlight and soil as the previous growing area. Dig a hole that is twice as wide as the sucker root mass and deep enough so the sucker is at the same depth as it was in the original planting area. 5. Set the root ball into the hole so the sucker is straight. Pack soil around the roots to hold the sucker in place. Moisten the planting area with water to compact the soil and remove air pockets that may have formed. 6. Clip back long shoots with hand pruners so the new plant does not have as much leafy growth to support and can grow back shrubbier. 7. Apply water three times a week to keep the soil moist during the first month after planting when rain isn't present to assist with root establishment.

Chapter 3 Artificial regeneration – objectives, choice between natural and artificial regeneration, essential preliminary considerations.

ARTIFICAL REGENERATION

Renewal of a forest crop by artificially or man-made means is called artificial regeneration. It is a group of methods which involve sowing and planting etc. Planting usually refers to the transplanting of sapling raised in nursery under protected conditions, where as at certain times the seedlings may also be procured from the forest itself grown under natural conditions and planting such seedlings is called wilding.

Artificial regeneration relies on seeding, planting of seedlings, or planting of cuttings. Particular prerequisites to the successful establishment of artificial regeneration are: • Presence of seed orchards or stands • Presence of a seedling industry (nurseries) • Availability of an adequate labour force • Site preparation (in most cases)

Objectives of artificial regeneration: The artificial regeneration is being carried out to fulfill the objectives mentioned below :

1. Reforestation : The artificial regeneration carried out on lands which were originally forested is called reforestation. The purpose of reforestastion is a) supplementing natural regeneration b) replacing natural regeneration c) Introduction of other species. 2. Afforestation : Raising of forest crop of land which were not originally forested. This may be under taken for productive, protective and bio-aesthetic purposes.

Factors affecting the choice between Artificial and Natural regeneration;  Risk of loss and deterioration of soil  Crop composition  Genetic consideration  Risk of damage by pest  Flexibility of operation  Density of stocking  Yield  Time factor Essential preliminary consideration: After deciding in favor of artificial regeneration, decision has to be taken on the following essential preliminary considerations; I. Choice of species: - depends on the following factors. a) Climate and micro-climate b) Soil condition  Lime rich soil  Stiff kankar clay  Clayey soil  Soils with soluble salt c) Stage of succession d) Objective of management e) Consumer's requirement f) Growth rate g) Availability of suitable exotic h) Ease of establishment i) Cost j) Effect on site Mixture in plantation: In order to decide (pure or mixed), merits and demerits of pure and mixed crops may be assessed from the point of view of following considerations:- 1. Soil deterioration 2. Resistance to diseases 3. Damaged by wild animals 4. Increment of total yield 5. Difficulty in execution of silvicultural operations as well as management. Kinds of Mixture: A) Temporary mixture: For following objectives Objectives of temporary mixture; a) Providing protection against adverse factors. b) Providing competition in the early stage to obtain better bole form. c) Providing additional revenue. d) Providing covers to the ground and suppression of weeds. B) Permanent mixture: In which the mixed species remains with main species throughout the rotation of the crop. Objective: - to avoid risk to which pure crops are exposed. Kinds of Permanent mixture: a) Horizontal or even aged mixture b) Vertical or uneven aged mixture or storeyed mixture. Pattern of mixture: a) Intimate mixture b) Line mixture c) Strip mixture d) Block mixture II. Selection of site III. Choice of methods of artificial regeneration a) Direct seed sowing or b) Seedling planting Advantages of sowing Disadvantages of sowing Advantages of planting Disadvantages of planting The choice between the two methods (sowing or planting) of artificial regeneration depends upon;  The species to be raised  Condition of site  Availability of seed  Cost Spacing: - Spacing varies with species and the local conditions. The following factors govern the spacing; a) Rate of growth of species: - Fast growing species have wider spacing and slow growing species have closer spacing. b) Habit of branching: - large number of branches reduce the volume and value of timbers so, plant in close spacing. c) Number of annual rings per centimeter: - this type of denser wood species wider spacing. d) Height of planting material: - If tall plants are to be used for planting, the spacing should be wider, if small planting stock is to be planted spacing should be closer. e) Site factor: - In dry area, spacing should be closer. f) Inter cultivation: - wider spacing for tractor ploughing and cultivation of agricultural crops, as a intercropping tree with agro-forestry crops. g) Market for small sized timber: - The crop raised in closer spacing. h) Fruit production as objective: - Spacing should be wider depends on fruit bearing species. i) Cost: - Close spacing requires much cost than wider spacing. Therefore availability of funds has a great influence on the spacing to be adopted. Methods of Artificial Regeneration: Artificial regeneration can be done either by sowing of seed directly in plantation area or by planting seedlings or cuttings obtained from some nursery. Regeneration from seed Kinds of Sowing: sowing may be done in any of the following ways: a) Broad-cast Sowing: It is the process of scattering of seed over the whole area, either that on which the crop is to be raised directly or a nursery bed. It is generally recommended for stocking burnt areas, abandoned cultivation, landslides and grassy blanks. b) Line Sowing: In this method, sowing of seed is done in drills or single lines. Drills or lines are made at pre-determined intervals after digging soil in those places. It may be continuous line sowing when drill is made from one end of plantation to other end while it may also be uninterrupted line sowing in which the area consists of dug up and sown portion alternating with undug and unsown portion. If the sown portion of line is opposite to unsown portion of adjacent lines it is called interrupted and staggered line sowing. c) Strip Sowing: In this method, seed is sown in narrow strip prepared usually at definite intervals from one another and are generally 45cm to 90cm or even 120cm wide. Like line sowing strip sowing may be continuous, interrupted and staggered. Line and Strip sowing are done either on ridges or in trenches, depending on rainfall. In high rainfall, moist and areas liable to water logging sowing is done on ridges (10 to 20cm higher than ground level) and such sowing is called ridge sowing where as in dry and low rainfall areas, the seed is sown in trench and called trench sowing. In areas with uncertain rainfall ridge ditch sowing is done in which earth is filled back in trench in sloping manner leaving part of trench unfilled. In case of poor rainfall, lowest row sowing will be successful, in case of moderate rainfall; the middle row will be successful while in heavy rainfall ridge sowing will be successful. d) Patch Sowing: It is the sowing of seed in specially prepared patches i.e. circular or rectangular made at regular intervals. It‘s important merit is that the patch may serve as small nurseries inside the plantation. In high rainfall areas or areas liable to water logging patch sowing is done on mound called mound sowing. Mounds are usually 1.2m × 1.2m at base and 60cm × 60cm at top while in dry areas, sowing is done in pits called pit sowing and are usually 1.5m long, 1.5m wide & 30 cm deep. e) Dibbling: In this method, sowing is done in shallow holes made with suitable instruments at definite intervals and is used for such species as Juglans, etc which produce large seeds. Regeneration from vegetative parts (sprouting, root suckers, and coppice etc.) Regeneration from vegetative parts can be obtained by any of the following methods:  Coppice  Root sucker  Cutting  Layering  Grafting  Budding  Sprouting REGENERATION FROM SPROUTING REGENERATION FROM ROOT SUCKERS Root sucker is a shoot rising from the root of a woody plant. It is that method of vegetative reproduction in which a root of a plant is partially or wholly cut to produce a shoot called root sucker. Natural regeneration by root suckers is not being attempted on any large scale anywhere in this country. This method used to be followed, sometimes, on the canal bank plantations in India and the chief species in which this was affected was sissoo. Where this method was followed, it was usual to dig continuous or discontinuous circular trenches with diameter of about 6 m round the isolated trees so that their roots may be severed and root suckers produced, which, with tending, could be developed into trees. The trees produced in this way are liable to wind-throw and poor in growth and therefore this method is not being favoured now. Diospyros root suckers are sometimes encouraged because the root suckers produce best biri leaves. REGENERATION FROM COPPICE Coppice is that method of reproduction in which the tree, plants or, the seedlings of a species when cut from near the ground level, produce coppice shoots. Coppice shoot is defined as ‗a shoot arising from an adventitious bud at the base of a woody plant that has been cut near the ground or brut back‘. Natural regeneration by coppice can be obtained either by: (1) Seedling coppice; or (2) Stool coppice (1) Seedling coppice is defined as the ‗coppice shoots arising from the base of seedling that have been cut or burnt back‘. This method of obtaining natural regeneration is used for cutting back woody shoots and established reproduction which is not making any progress so that they may produce vigorous shoots and soon develop into saplings and later into poles. It is generally used in case of Sal and Teak. (2) Stool coppice is the coppice arising from the stool or a living stump. In this method, regeneration is obtained from the shoots arising from the adventitious buds of the stump of felled tree. The coppic shoots generally arise either from near the base of the stump or from its top. Of the two, those arising from near the base are better because they get established easily. The shoots arising from near the top of the stump are liable to be damaged by the rotting of the upper portion of the stump as well as by wind, etc.

Natural versus artificial regeneration If target stocking with preferred species can be met within a reasonable period by use of advance regeneration, regeneration from seed or vegetative reproduction, then there is no need to use artificial regeneration (planting or seeding).

Steps involved in Artificial Regeneration : 1. Choice of species 2. Site selection 3. Choice of method of sowing 4. Spacing 5. Arrangement of staff and labour 1) Choice of species : Selection of a suitable species for artificial regeneration is very essential, because it involves high expenditure. Selection of species for artificial regeneration will depend upon

 The habitat conditions and Silvicultural requirements  Objects of raising plantations (Type of management)  Effect of species on the habitat  Resistance to insect pests and diseases  Silviculture system to be adopted 2). Site Selection : Selection of a suitable site for raising the particular plantation is very important. While selection the site the following factors are to be taken into account.  Climatic conditions of the area.  Topography.  Soil conditions 3) Choice of Methods: Sowing and planting are the two methods of artificial regeneration. Depending on the species and site, suitable method either for sowing or planting should be selected. 4) Spacing: Distance between two plants in a plantation forest is spacing, which depends upon species, site, purpose and management 5) Arrangement of Staff and Labour: Trained persons of the forestry department should supervise the work for successful regeneration. Arrangement of labour may be made by engaging daily wage workers through contractors, and labour having permission to raise the agricultural crops in plantation area. For successful artificial regeneration certain technical aspects of tree species is more essential. a) Seed Collection and Storage: These are very important operations in plantation programme. The seed must be collected from healthy and well-formed trees of proper ecotype. It is important to have seed orchards of each species. In absence of seed orchards good quality neighbouring forest area may be selected as seed stand and seeds must be collected from such areas. The seed should be collected from good trees which are dominant, middle aged, tall, vigorous, well shaped and straight trees but not from immature, over mature, suppressed branchy, diseased, insect infested or low grade variety. Land Preparation : Planting area must be suitably prepared for plantation work. A well prepared plantation site may help in proper growth and development of trees. a) Soil working : Complete soil working by tractor, bulldozers, sub soilers may be done in case of large plantations as deep soil working has its own advantages of checking weed growth etc. b) Digging pits : Many species are planted in pits of 1x1x1 feet (30 cm x 30 cm x 30cm) and on some special sites and for some species 2 x 2 x 2 (60 x 60 x 60) are dug. 1) Ordinary pits : Are recommended for clayey and saline and alkaline soils. 2) Saucer shape pits : Are suitable for sandy soils. 3) Ring pits : Are dug in scanty rainfall areas and very sandy soils to accumulate maximum rain water at the root zone. 4) Ridge ditch : Ridge ditch is partly filled in trench. Sowing or planting is done in the bottom of the trench or sloping area. Ridge ditch system is followed in sloping lands where ridge is made on lower slope and the ditch on upper slope. 5) Double trenches : Are also suitable for murramy areas and where hard pan formation exists in sub-soil. 6) Contour trenches : Suitable for hilly areas. 7) Brick planting : Suitable for sandy coastal areas. In desert sands and mobile sand dunes, the sand dunes should be first stabilized by spreading leaf litter or brush wood etc. 8) Drainage : For successful plantation drainage channels should be opened in water logged areas. Planting Methods : 1) Planting with roots : While planting with naked roots, the important considerations are: a) Collar should beat the level of soil surface. b) The tap and sinker roots are not doubled up c) The planting pits should be at least as deep as the length of roots of seedlings. 2) Planting with ball of earth : Many species do not tolerate the exposure of the root system specially when they grow large. For preparation of ball of earth the plant must be uprooted in such a way from the nursery that the roots come out in natural position withball of earth. 3) Container planting : a) Dona method of planting : Dona is a cup shaped structure made up of leaves of Bauhinea vahlii and Butea monosperma. The donas are placed on the ground and watered after sowing seeds until the seedlings are well rooted. The seedlings are then planted out. b) Mossed transplants : In Eucalyptus and in some other species when the seedlings are very small, they are mossed by embedding them (with some earth) in a cylindrical role of moss about 15 cm long bound with fibre and then kept in a shade. The plants are shifted from one place to another place within week in order to check the growth of the roots outside moss until they are planted. Mossing of seedlings of Eucalyptus is being taken to protect them from frost in ootacamand and other cooler places when seedlings are 7.5 to 10 cm. tall. c) Brick planting : Bricks are prepared from the mixture of local soil sand or clay and manures are used in planting out. There is a cavity in the centre of the brick which is filled with good soil to receive a seedlings are planted along the bricks in sand dune areas. d) Planting in Polythene bags : This method is mostly advantages on difficult sites. The plants are developed with minimum disturbance. The bottom of the bags are opened while planting out. 4. Stump Planting : The advantages of stump planting are 1) Practically no damage in transport 2) Handling and planting are easy 3) Lot of reserve food materials in stumps. The stumps should be 20-25 cms. The root portion is about 18-20 cm and 2-5 cm shoot. Tectona, Sissoo, Albizzia spp are planted by this method successfully. 5. Vegetative propagation : Root suckers, branch and stem cuttings, root cuttings, layering, grafting and budding are most commonly used for vegetative propagation of forest plants. Spacing : One of the advantages of artificial regeneration over natural regeneration is the control of no. of trees per unit area and their uniform distribution over the land area. An optimum spacing will produce the greatest volume in proper size form and quality of trees required. Trees with wider spacing grow more rapidly than those planted in narrow spacing. Trees planted at wider spacing have greater taper, thicker branches with deeper and wider crowns. Closer spacing is adopted in order to facilitate natural pruning for production of clean and straight bole. Too close spacing results in thinner diameter of trees. The spacing depends upon 1) Site 2) purpose 3) Management 4) Species. Season of Planting : Planting seasons varies with the species and the commencement of monsoon, Teak and sisso stumps are planted with the onset of rains. casuarina, Eucalyptus and other pot culture plants are planted after the monsoon sets in or advanced to some extent. In the east coast where north east monsoon is dependable, planting is done in September – October. In area of South west monsoon planting is done during June – July. Advantages of artificial regeneration • Controlled plant density • Predictable seedling production • High flexibility • Low management intensity • Option of introducing improved seed or plant material • Changing species and/or varieties Disadvantages of artificial regeneration • Labour-intensive • Temporarily disturbed root development • Less adapted to micro-sites • Cost-intensive

Chapter 4 Crown classification, tending operations – weeding, cleaning, thinning – mechanical, ordinary, crown and advance thinning. Crown classification: A classification of trees based on crown position relative to the crowns of adjacent trees are called as crown classification. There are two ways for crown classification. Traditional: 1. Open crown. Trees with crowns that have received full light from above and from all sides throughout their lifespan, particularly during the early developmental period. 2. Dominant. Trees with crowns extending above the general level of the crown canopy and receiving full light from above and partly from the sides. These trees are taller than the average trees in the stand and their crowns are well developed, but they could be somewhat crowded on the sides. Also, trees whose crowns have received full light from above and from all sides during early development and most of their life. Their crown form or shape appears to be free of influence from neighboring trees. 3. Co-dominant. Trees with crowns at the general level of the crown canopy. Crowns receive full light from above but little direct sunlight penetrates to their sides. Usually they have medium-sized crowns and are somewhat crowded from the sides. In stagnated stands, codominant trees have small-sized crowns and are crowded on the sides. 4. Intermediate. Trees that are shorter than dominants and co-dominants, but their crowns extend into the canopy of dominant and co-dominant trees. They receive little direct light from above and none from the sides. As a result, intermediates usually have small crowns and are very crowded from the sides. 5. Overtopped. Trees with crowns entirely below the general level of the crown canopy that receive no direct sunlight either from above or the sides. 1. Superstory. The live crown top is at least two times the height of the top of the overstory canopy zone. The tree is open grown because most of the crown is above the overstory canopy zone (pioneers, seed trees, whips, remnants from previous stands). 2. Overstory. The live crown top is above the middle of the overstory canopy zone. 3. Understory. The live crown top is at or below the middle of the overstory canopy zone. 4. Open Canopy. An overstory canopy zone is not evident because the tree crowns in this condition are not fully closed (< 50% canopy cover). Most trees in this stand are not competing with each other for light. Alternative: Crown position. First, an overstory canopy zone is identified, which encompasses the crown lengths of trees in the primary overstory. Once this zone is established, trees are rated with regard to their position in relation to its midpoint and upper bound:

Crown exposure. Tree crowns are divided vertically into four equal sides (or faces). The number of sides that would receive direct light if the sun were directly above the tree are then counted; one is added if the tree receives any direct light from the top, for a possible total of five faces. In order for a side to be counted, more than 30 percent of the tree length on that side must have live foliage exposed to direct light.

TENDING : Tending is a broad term given to operations which are carried out for the well being of a forest crop at any stage of its life involving operations both on the crop itself and on its competing vegetation. Objectives of Tending Operation 1) To Improve the Hygiene of the Crop: By removing dead, dying and diseased trees, hygiene or health of tree can be maintained well. 2) Salvage of Anticipated Losses of the Merchantable Volume: A large number of trees die of suppression. This amount contributes of about 20 per cent of the merchantable volume. Thinning contributes a substantial amount in the total yield of crop. Thinning helps in shortening of the rotation. Reduction in number of trees in thinning increases the diameter of the remaining trees. 3) To assure the Best Physical Conditions of Growth: The objective of the thinning is to keep growing stock somewhere within the range. The effect of extreme competition is reflecting by decline in the rate of growth with increasing density in crops which are very dense. Thinning increase the diameter of the crops. Thus thinning may be essential tool for shortening the rotation of a crop. 4) To Obtain Desired Crop: Thinning helps to improve the stand structure. It ensures a uniform and proper distribution of trees all over the area. This enables the trees to tap water and nutrients from a larger area. The composition of the crop can also be improved. The less valuable species may be removed in thinning and the important and valuable species may be retained for future. 5) Improvement of Stand Composition, Regeneration and Protection: If an undesirable species is not eliminated during regeneration stage it can be done during thinning to a certain extent. Thinning helps in obtaining suitable seed bearers for obtaining successful regeneration. The dead, drying and diseased trees are removed to afford protection from insect pest, disease and fire because these trees may serve as a source of infection. 6) Improvement in Wood Quality: Thinning may also improve the quality of wood because trees with higher diameter are likely to be of better quality than smaller ones. 7) To Increase Net Yield and Financial out turn from a Stand: Thinning help to obtain returns early. The sale of thinning material helps to reduce investment burden because of early returns from thinning and shortening of rotation. 8) To Help Decomposition of Raw Humus: In temperate forests, thinning increases light and temperature on the forest floor and causes mechanical disturbance which help the decomposition of raw humus and release of nutrients, etc.

Tending is an important silvicultural operation which helps in the production of high quality timber, maximizing returns per unit area and ensures overall well being of the forest. Some operations of tending are :

1. Weeding: - The removal or cut back of all weeds. It is done in seedling stage in nursery or in a plantation or in a forest crops. It is done to reduce the root competition and improve the light condition for enhancement of growth of plants. Weeding should be done before weeds have started suppressing the seedlings and seedling have stopped growing, after the growth period is over. Three weeding in first year, two in second year and one in third year but in case of fast growing spp. only one or may be two years only. 2. Cleaning:- is a tending operation done in a sapling crop, involving the removal or topping of inferior growth including individuals of favored species, climber cutting etc. when they are interfering with the better grown individuals of the favored species. It merges with thinning as saplings grow into poles. Objectives:- i. To improve light condition. ii. To reduce root competition and transpirational water loss. Method of cleaning: i. Cutting back of shrubs and herbaceous growth. ii. Cutting back of the individuals of inferior species. iii. Cutting back of the malformed or diseased individuals of the desired species. iv. Singling of coppice shoots of the favored species. v. Climber cutting 3. Thinning: Thinning may be defined as a felling made in an immature stand for the purpose of improving the growth and form of the tree that remain without permanently breaking the canopy. It is the reduction of trees in an immature stand for the purpose of improving the growth and form of the trees that remain without permanently breaking the canopy of future trees. Thinning is an operation that artificially reduces the number of trees growing in a stand with the aim of hastening the development of the remainder. The goal of thinning is to control the amount and distribution of available growing space. By altering stand density, foresters can influence the growth, quality, and health of residual trees. It also provides an opportunity to capture mortality and cull the commercially less desirable, usually smaller and malformed, trees. Unlike regeneration treatments, are not intended to establish a new tree crop or create permanent canopy openings. Thinning greatly influences the ecology and micro-meteorology of the stand, lowering the inter-tree competition for water. The removal of any tree from a stand has repercussions on the remaining trees both above-ground and below. Silvicultural thinning is a powerful tool that can be used to influence stand development, stand stability, and the characteristics of the harvestable products. When considering intensive conifer plantations designed for maximum production, it is essential to remember that tending and thinning regimes and wind and snow damage are intimately related.

Objectives:  To distribute growth potential of a site amongst the trees retained.  To increase the net yield of timber and money from a stand  To obtain earlier returns from capital invested in a stand  To utilizethe thinned material  To shorten the rotation  To produce a different smaller size of timber which can meet a different object of management  To maintain hygienic conditions in the stand  To allow intermediate harvests of small and large woods before the final harvest satisfying the needs of the users  To favor natural regeneration in a stand though not of prime intention  To control species composition in a stand by removing undesirable species during the operation

When?  The time for thinning a stand is determined when the crowns of the adjacent trees are close together and there is no further space into which individual trees can grow  Removing of unwanted species carries out when there is a need to change species composition in a forest stand  When users demand of fuel wood and small wood has to be fulfilled  Thinning is done any time when dead and diseased trees are sighted.

How ?  The number of plants, inferior in quality, is reduced in one or several operations  Remove all dead and diseased trees at first instance. They can be removed at any time  Trees that are dying (75% dead) may be retained temporarily if removal of crops exposes the soil

Fig,: Thinning

Effect of thinning: - following results may be obtained after the different types of thinning:-  Physiological effect &  Mensurational effect 1. The regulation of hygiene of the crop by removing dead, dying, diseased and infected plants. 2. Got assure best physical condition of growth, increase the rate of growth, shortening the rotation. 3. It ensures uniform distribution of trees all over the area. 4. It helps to choose the right type of tree of right spp. as future crop. 5. It minimizes the climber damage and help to reduce the fire hazard. 6. It helps to get the timber of desired quality and strength. 7. It keeps sufficient stock in the crop for the development of better bole form and maintains the soil fertility. 8. It increases the net yield of timber and money from the stand. 9. It helps to obtain the earlier returns without interest from capital in a stand.

Methods of Thinning: 1) Mechanical Thinning: (also called stick thinning): A thinning in which the trees to be cut are selected by some rule of thumb, e.g., trees in alternate diagonals or rows, alternate trees in alternate rows or every second, third, etc., line or a minimum spacing gauged by a standard stick.

This type of thinning is usually applied in young crops or young plantations before the crown differentiation has taken place. In teak plantations of Kerala, first and second thinning carried out at the age of 4 and 8 years are usually mechanical thinning and consists of the removal of alternate diagonal lines or rows of trees reducing the stocking from 2,500 trees per ha to 1250 trees per ha after the first mechanical thinning and then to 625 trees per hectare after second thinning with spacing 2 in x 2 in to about 2.85 in x 2.85 in and then ultimately to 4 in x 4 in after second thinning.

2) Ordinary Thinning: (also called low thining or German thinning or thinning from below): The method of thinning in common use that consists in the removal of inferior individuals of a crop, starting from the suppressed, then taking the dominated and lastly some of the dominants. This is called as "Low Thinning". In ordinary thinning, the trees are removed from lowehas been devised to follow the nature i.e. those trees, which have been unsuccessful in the struggle of existence, are removed first. Ordinary thinning is the most commonly used thinning practice in forestry. It is most for light demander species. This method of thinning is useful and may be economically applied in species and areas where small size timber has a market. The method is simple in execution. Removal of lower crown classes suitable for area where there is no danger of soil deterioration. Forests infested with climbers and where there is risk of crown fire. Ordinary thinning has several commands. Grades of Ordinary Thinning: i) Light Thinning (A Grade): This is limited to the removal of dead, dying, diseased and suppressed trees. ii) Moderate Thinning (B Grade): This consists in the further removal of defective eliminated stems and whips. iii) Heavy Thinning (C Grade): This consists in the further removal of the remaining dominated stems and such of the defective co-dominants as can be removed without making lasting gaps in the canopy. iv) Very Heavy Thinning (D Grade): The distinguishing features of this grade is that, it also takes some of the dominate, subject to the some condition of not making any lasting break in the canopy. v) Extremely Heavy Thinning (E Grade): This is the heaviest thinning that can do in a crop without making permanent gaps in the canopy. More of the dominant stems even of class (a) are removed.

3) Crown Thinning: (High thinning or French thinning or thinning from above): A method in which thinning is primarily directed to the dominant trees in a regular crop, the less promising ones being removed in the interest of the best available individuals; the dominated and suppressed stems are retained if they are not dead, dying and diseased.

The less promising one being removed in the interest of the best individuals; the dominated and suppressed stems are retained unless they are dead, drying or diseased. Aims at removing the inferior trees from among the dominant class. Advantages of Crown Thinning:

Crown thinning offers several advantages over other methods of thinning: i) Crown thinning provides better environment for growth and development of retained dominant trees. ii) The trees of lower crown classes are not removed. iii) The pressure of trees of lower crown classes results better pruning of side branches. iv) It helps in protection of the site and reduces the damages due to frost, snow, wind etc. Disadvantages of Crown Thinning:

The main disadvantages of crown thinning are i) There is higher root competition for moisture and nutrients. ii) Abstraction in felling, logging and extraction of tinned material. iii) Crown thinning is more flexible method than ordinary thinning. It requires greater skill in execution. iv) Closer look on suppressed and dominated trees would be necessary 4. Advance thinning (also Craib‘s thinning): A thinning done in a regular crop in anticipation of suppression. It was developed by Craib and O‘Connor for wattle and pine plantation in south Africa. Thinning is done after the trees have been adversely affected by the competition of their neighbors. It should be done before competition actually sets in. 5. Free thinning (devised by Heck): A method of thinning in which attention is concentrated on evenly spaced selected stems (called elites or alpha stems) which are retained until maturity or til the last thinning or two, thinning being directed to the removal of other stems hindering their optimum development. 6. Maximum thinning: It is the modification of Heck‘s free thinning developed by Gehrhardt. It is defined as a method of thinning which ‗ aims at putting as high a proportion possible of the total potential increment of the area on the retained stems; from an early stage the number of such stems limited to the minimum that can fully utilize the growing tree. It is heaviest form of free thinning so that there are no trees other than elites. As the thinning is extremely heavy, it may result in deterioration of site due to exposure, infestation of the area with shrub growth, production of knotty timber. 7. Selection thinning: A method of thinning directed to obtain and/or maintain selection composition in a crop, with all diameter classes adequately represented.‘ It is carried out in all canopy classes removing the trees of the following characteristics:  Dead, dying and diseased trees  Inferior trees which restrict the development of their neighbors from all sides  Trees which are less valuable than their neighbors  Trees which are of no special importance as regards desirable crop mixture  Inferior trees standing over groups of well-grown advance growth which may also be thinned.

Regulation of thinning: - As we know the importance of thinning as a silvicultural treatment. The time of first thinning creates problem because the materials from the first thinning are usually unsalable, and the materials lying on the forest floor which increase the fire hazard. Due to that always a tendency to avoid/postponed first thinning materials are saleable. But the thinning impact on the tree growth, production of quality of timber, sustain the composition of stand, maintain the hygienic condition, so tendency postponing the first thinning is harmful silviculturally as well as economically in the final analysis . The first thinning should be done whenever it is silviculturally necessary, whether the thinned materials should be saleable or not and the thinned materials should be removed or disposed of even at cost so not to constitute a danger to the crop. The first thinning is usually prescribed by at a certain age keeping the average growth in view but sometimes due to better or poor site and environmental factors, the growth is faster or slower, therefore there is often, a provision for inspection of plantation and advancing or postponing thinning in areas where growth may be above or below to normal respectively. The first thinning is also sometimes, timed by crop height, crop age, density of planting, objective of plantation and management, so it may varies species to species. For example in case of teak in which first thinning is carried out when the crop height is 7 to 9 m. which is reached in 3rd, 4th and 5th year in site quality II, III and IV respectively, similarly second thinning is carried out when the height of crop is from 10.7 m to 13.7 m. (34' to 45'ft) which is reached in 6th, 8th &10th year in site quality II, III & IV, respectively. Regarding the planting space/density, when dense, it should be thinned when the competition for light & nutrient are seen, first thinning should be done to reduce the competition. The thinning of different species in different stands should be regularly according to need up to pre mature age. Limitation No numerical basis showing the levels of optimum basal area for the types of forest prevalent in the country has been found.

Chapter 5 Forest mensuration – objectives, diameter measurement, instruments used in diameter measurement. What is measuration? It is defined as the act, process, art or science of measuring; that branch of mathematics concerned with measures of approximate of lengths of lines, areas of surfaces and volumes of solids. GROWTH:- It is a phenomenon of increase in size or general process of change with time. INCREMENT:- A quantitative increase in size which results the phenomenon of growth. YIELD:- This refers to the accumulated increment, the aggregation of material useful for some purpose at a particular time. OBJECTIVES OF MEASUREMENT IN FOREST 1. VALUATION: The more intensive the utilization the nearer will the out-turn approaches the total volume of the tree. Measurement will prevent cheating between the seller a buyer and consequently a standard would set. 2. MANAGEMENT: Measurement is undertaken to meet a continuous demand, the wood producer is interested in the extent of the forest and also in the quantity of the material standing in the forest. 3. RESEARCH: Measurement is adopted to meet future demand in quantity and quality of the i.e. Research is conducted into the system of Silviculture and management which mean result in higher rate of production or in maximum production of the desired material product.

Diameter Measurement . A diameter is a straight line passing through the center of a circle or sphere and meeting at each end of circumference or surface. . The most common diameter measurements taken in forestry are of the main stem of standing trees, cut portions of trees and branches. . Diameter measurement is important because it is one of the directly measurable dimensions from which tree cross sectional area and volume etc. can be computed. . The point at which diameters are measured will vary with circumstances.

DBH measurement and its significance . The most frequent made by forester is diameter at breast height (dbh). . DBH is defined as the average stem diameter outside bark, at a point 1.3 m above ground as measured . The rational of DBH measurement of individual trees is to estimate the quantity of timber, fuel wood or any other forest products which can be obtained from them. . These measurement are also necessary for making inventory of growing stock as well as to correlate height, volume, age, increment with most easily determinable dimension i.e. dbh DBH has been accepted as the standard height for diameter measurement because … . It is a convenient height for taking measurement. . It is economic (the base of the tree is generally covered with the grasses and shrubs and even thorns sometimes). . Majority of the trees develop root swell near the base (abnormalities at the base). . It gives a uniform point of measurement and standardization is maintained.

Rules of DBH measurement and instruments used

Rules of DBH measurement . Moss, creepers, lichens and loose bark found on the tree must be removed before measuring the diameter over bark. . Breast height (BH) should be by means of a measuring stick on standing trees at 1.3m above the ground level.

Figure: Level ground

. BH point should be marked by intersecting vertical and horizontal lines 12 cm long, painted with white paint.

. On sloping land, the diameter at BH should be measured on the uphill side.

Figure: Sloped ground Figure: Uneven ground

. In case of the tree is leaning, dbh is measured along the tree stem and not vertically, on the side of the lean for trees growing on flat ground and on the uphill side, for trees growing on sloping ground.

Figure: Leaning tree Figure: Crooked tree

. The dbh should not be measured at 1.3m if the stem is abnormal at the level. BH mark should be shifted up or down as little as possible to a more normal position of the stem and then dia. Measured.

Figure: Defect at 1.3m Figure: Buttressed tree

. BH should be taken at the lowest point above which the buttress formation is not likely to extend

. When the tree is forked above the BH, it is counted as one tree, but when it is forked below BH, each fork should be treated as though it were a separate tree.

Figure: Fork at 1.3 m (1 tree) Figure: Fork above 1.2 m (1 tree)

Figure: Fork below 1.3m (2 trees: alternative method) Figure: Fork below 1.3 m (2 trees)

Diameter measuring instruments . The most commonly used instruments for measuring diameters at BH are: Diameter tape, calipers, Biltmore stick and other optical instruments. . Collectively, instruments employed in determining tree diameters are referred to as dendrometers.

Biltmore stick . It is a specially graduated stick used for diameter measurement. . The stick measures a tangent to a circle, from a point, exactly 25 inches from the tree. (The stick is graduated to show the diameter as if it were projected from the user‘s eye into the tree.)

. This specially graduated stick is placed against the tree trunk with the diameter scale facing the user. Keep your head 25 inches from the stick, and without moving your head, Figure: Measuring with a Biltmore stick slide the stick so that the left edge of the stick appears to line up exactly with the left edge of the tree trunk. . Keep your head stationary, and move your eyes to read the number on the scale those lines up exactly with the right edge of the tree trunk. That number is a reasonable estimate of the diameter of the tree at breast height (DBH). . If the measurement of the right edge of the tree falls between two numbers on the scale, the lower number is used as the diameter. . The Biltmore stick tends to be inaccurate on large timber. Trees over 20 inches should be checked with a diameter tape.

Diameter tape

Figure: Tape

. The diameter of a tree cross section may be obtained with a flexible tape by measuring the circumference of the tree and dividing by π(D=C/ π). . The diameter tapes used by foresters, however are graduated at intervals of π units (in or cm), thus permitting a direct reading of diameter. . A diameter tape is a measuring tape that has scales on both sides: one side is specially marked to show the diameter of a tree, and the other is a normal scale.

Precautions in using tape . The tape should not be old. . It must lie flat against the tree and not in twisted manner. . It must lie in a perpendicular to the axis of the tree. . The tape should be taken care of.

Advantage of tape . Tape is convenient to carry. . It does not require constant adjustment. . Only one measurement is needed even with irregular trees. . Diameter measurement by tape is the easiest in the case of logs lying on ground. . The errors in case of tape are always positive and systematic. . Tape negotiates the whole circumference of the tree. . Tape readings are more consistent. Disadvantages of tape . The tape exaggerates the diameter if the tree has rough bark. . It is somewhat slower to particularly in areas with dense shrub growth. Difference in tension of the tape due to elasticity affects true diameter.

Calipers

Figure: Caliper

. Calipers are often used to measure tree dbh or when diameters are less than about 60 cm. . A calipers may be constructed of metal, plastic or wood, consists of a graduated beam/rule with two perpendicular arms. . One arm is fixed at the origin of the scale and the other arm slides. When the beam is pressed against the tree and the arms closed, the beam of the caliper can be read on the scale. . For an accurate reading, the beam of the caliper must be pressed against the tree with the beam perpendicular to the axis of the tree stem and the arms parallel and perpendicular to the beam.

Diameter measurement using calipers . Place the calipers over the stem at the required height. . Record the diameter then take another measurement at a right angle to the first and record this measurement and . Calculate the average of the two measurements and record to the nearest to 0.1cm.

Precautions in use . The calipers must be placed on the tree with movable arm well opened and must not be forced on the tree. . The reading must be taken before the caliper is removed from tree. . If the cross section of the stem is more or less elliptical, it is necessary to measure two diameters. . Calipers must be placed at right angles to the axis of the tree. . The two arms of the caliper must be in contact with the tree and the movable arm should be at right angles to the scale arm. . Not only should the two arms of the caliper be in contact with the tree but the scale arm must also touch it.

Advantages . Diameters can be read directly in centimeters and millimeters, thus making the instrument applicable for precise scientific work. . By pressing the arms against the tree bole, the loose swollen bark is crushed out and irregularity from this source is avoided. . It is adaptable for use by unskilled labour. . The errors are both positive and negative and therefore the chances are that they may neutralize to give more accurate results than the tape.

Disadvantages . They are not accurate when not in adjustment. . Calipers sufficient in size to measure large trees are very awkward to carry and handle. . Two measurements have to be taken on every tree to get the correct diameter. . Movable arms often stick when the scale is wet or dirty, thus wasting a lot of time.

Chapter 6 Non instrumental methods of height measurement - shadow and single pole method; Instrumental methods of height measurement - geometric and trigonometric principles, instruments used in height measurement.

Height Measurement . Height is the linear distance of an object normal to the surface of the earth. . Tree height is the vertical distance measured from the ground surface. . Height of standing tree is measured to find out its volume. Height of selected trees in a forest are also required to read volume tables, form factor tables, yield tables etc. . Lastly, heights of trees are required to find out productive capacity of site. Height is generally considered as an index of fertility and with the knowledge of age it gives a reliable measure of the site quality of a locality. Total height of a standing tree is the distance along the axis of the tree stem between the ground and the tip of the tree. Bole height is the distance along the axis of tree between ground level and crown point. (crown point is the position of the first crown forming branch). Commercial bole height is the height of bole that is usually fit for utilization as timber. Height of standard timber bole is the height of the bole from the ground level up to the point where average diameter over bark is 20cm. Stump height is the distance between the ground and basal position on the main stem where a tree is cut. Crown length-The vertical measurement of the crown of the tree from the tip to the point half way between the lowest green branches forming green crown all round and the lowest green branch on the bole. Crown height - The height of the crown as a measured Figure: Tree height vertically from the ground level to the point half way between the lowest green the lowest green branches forming green crown all round.

Principles of height measurement . Instruments used for measuring tree heights are collectively referred to as hypsometers. . All height measuring instruments are based either on geometric principles of similar triangles or on trigonometric principles based on relations between the sides of right angled triangle.

Trigonometric principles The principles follow the basic rules of trigonometry for deriving heights of trees from distance and angle measurements. Two laws are applicable for this purpose and they are: tangent law and sine law. Instruments based on Trigonometrical principles are Brandis hypsometer, Abney‘s level, Haga Altimeter, Topographical Abney‘s level, Relaskop, Tele Relaskop, Barr and Stroud dendrometer, Blume-Leiss hypsometer

Tangent law . Applicable to right angle triangle . For accurate results, trees must not lean more than 5° from the vertical, and the fixed horizontal distance must be determined by taped measurement.

Sine law . Applicable to non right angle triangle is useful in deriving tree height in difficult conditions. . Sines of angles are proportional to the opposite sides.

Geometric principle of similar triangle . Corresponding angles are equal and the corresponding sides are proportional. . By knowing the two sides of a triangle and only one side of the other, the corresponding second side of the latter can be found. . Useful in rough estimation, not reliable for precise work. Eg. Christen‘s hypsometer, Smythies Hypsometer etc.

Method of height measurement . Techniques for measuring tree height may be direct or indirect and essentially depend on the position or fate of the tree: . Felled trees - when the tree is on the ground, measurement of the linear distance from base to tip or to the merchantable limit is done directly with linear tape or graduated pole. . Standing trees - height can be measured by either direct or indirect methods (see below). Indirect methods are most common because the tip or merchantable limit is often inaccessible. Basic assumptions in measurement of standing trees: . The tree is vertical and . The tip and the base of the tree are simultaneously visible.

1. Direct methods  Climbing with tape and graduated pole. An accurate approach, but practicable only with some species under certain conditions. This technique is costly and dangerous and is normally restricted to experimental projects only.  Height sticks or rods. A reliable method, with an instrument error less than l%. However this method can also be expensive for trees in excess of about 20 m.

2. Indirect Methods (Non Instrumental methods and Instrumental methods)

Non instrumental methods of height measurement - shadow and single pole method:

1. Shadow method: a pole of convenient length is fixed upright in the ground and its height above the ground is measured. The shadows of the pole and the tree are also measured.

1.

2. Single pole method Pole of about 1.5 m length vertically at arm‘s length in one hand in such a way that portion of the pole above the hand is equal in length to the distance of the pole from eye.

AB/ab = EB/Eb i.e. AB = EB x ab/Eb Where,

Instrumental methods of height measurement - geometric and trigonometric principles, instruments used in height measurement:

Instrumental method . By using instruments like hypsometer, clinometer, altimeters, abneys level etc. . All these instruments are based either on geometric principle of similar triangles or on trigonometric principles.

Height by Geometric Methods Figure below illustrates the principle involved in measuring tree height by geometric methods. A vertical tree of height hT = AC, is standing on flat ground. A straight stick of known length lT = BC is positioned vertically at the base of the tree; such a stick would commonly be about 3−5 m long. An observer is standing a convenient distance away from the tree, with his or her eye at O. The observer holds a graduated ruler DF, positioned so that

Fig 6.1. Principle of tree height measurement using geometric methods the line of sight OC to the base of the tree is coincident with the zero mark of the ruler. Without moving his or her head up or down, the observer reads from the ruler the distance lR = FE, which coincides with the line of sight OB to the top of the stick against the tree. He or she reads also from the ruler the distance hR = DF, which coincides with the line of sight OA to the tip of the tree. Using straightforward geometry, the height of the tree can then be calculated from these measurements as hT = hR (lT / lR ) ...... (6.1) As an example, suppose the length of the stick standing against the tree was 5.0 m and the observer measured hR as 41.4 cm and lR as 8.0 cm. Then, the height of the tree would be calculated as hT = 5.0 ´ 41.4/8.0 = 25.9 m. Ground slope does not affect the geometry of this method. A number of different devices are available which use this principle. Often, the ruler is graduated in such a way that the computations in (6.1) are done implicitly, so that the tree height can be read directly from their scale. These devices are known generally as hypsometers. All the difficulties of measurement that apply with the trigonometric methods apply also with geometric methods. One advantage of geometric methods is that neither the distance from the observer to the tree nor ground slope need to be measured. A second advantage is that the equipment required is very simple (a stick of known length and a ruler only are required). Perhaps their disadvantage is that it is quite difficult physically for the observer to hold the ruler steady and, at the same time, keep in view all that needs to be sighted. However, with care, the accuracy of measurement of tree height using geometric methods should be about 0.5 m, the same as that with trigonometric methods.

Height by Trigonometric Methods Figure given below illustrates the principle involved in measuring tree height by trigonometric methods. A vertical tree of height hT = AC is standing on flat ground. An observer is standing a measured distance d = GC away from the tree and measures, at eye level O with some viewing device, the angles from the horizontal to the tip of the tree, aT, and to the base of the tree, aB. Angles measured above the horizontal should have a positive value, whilst those below the horizontal should be negative; in the case of Fig. (6.2) aT is positive and aB is negative. Using straightforward geometry and trigonometry, the height of the tree can be calculated from these measurements as hT = d[tan(aT ) + tan(-aB )]...... (6.2) where ‗tan‘ is the trigonometric expression for the tangent of the angle.

Heights measurement using the trigonometric principles Heights of up to 10–15 m are preferably measured with telescopic poles. For greater heights, clinometers (instruments that measure vertical angles) or hypsometers (specialized instruments that indicate height) are used. Some hypsometers (Christen, Merrit) use similarity of triangles, but at the present time most are based on trigonometrical principles. As an example, suppose the observer was standing 21 m away from the tree and measured the

Fig. 6.2. Principle of tree height measurement using trigonometric methods. angle to the tip as 48° and the angle to the base as −7°. Then, the height of the tree would be calculated as ht =21´ [tan(48) + tan(7)] = 21´ [1.1106 + 0.1228] = 25.9 m. Scientific calculators and computer programs provide the required trigonometric functions. In dense forest, it can often be difficult for the observer to see the tip of the tree. He or she needs to move around the tree and adjust the distance from which it is being viewed to make sure that the tip of the tree can be clearly seen. These problems are exacerbated if the wind is blowing the tips about. If the day is too windy, it simply becomes impractical to undertake height measurements. A tape may be used to measure the distance from the observer to the centre of the base of the tree. The angles may be measured with a hand-held clinometers (readily available from forestry suppliers) or, more precisely, with a theodolite. Theodolites are far slower to use and would only be countenanced if a very precise height measurement was required. Also available are various optical/mechanical instruments (Haga altimeter, Suunto hypsometer, Blume-Leiss hypsometer, Abney level and Spiegel relaskop), which incorporate a clinometer. These devices have scales which are calibrated so that the observer can read the tree height directly from the scale without having to do the computations required by (6.2). For routine tree height measurements, convenient electronic instruments are available today. These combine a clinometer with a distance measuring device. Some use the time of travel of sound waves to measure the distance, whilst the most recent use a laser. In both cases, a target is pushed into the stem of the tree to reflect back to the instrument the sound wave or laser light. Because the velocity of sound varies appreciably with air temperature, the instruments which use sound need to be calibrated regularly throughout the day as temperature changes. Once distance has been measured, the instrument is aimed at the base and tip of the tree and the inbuilt clinometer measures the required angles. The tree height is then calculated electronically by the device and displayed to the user. Heights measured by trigonometric means are often reported to an accuracy of the nearest 0.1 m. However, given the difficulties involved in sighting to the tips of tall trees, this is probably optimistic. In the example given above in geometric methods (6.1), a measurement error as small as +0.5° in the angle to the tip of the tree would result in a height estimate of 26.3 m, rather than 25.9 m as given in the example. In practice, an accuracy of no better than to the nearest 0.5 m might be a more realistic assessment for tree height measurements. Often the land surface on which the tree is positioned is sloping, rather than flat as in Fig. (6.2). To allow for this, the observer needs to measure also the angle of the slope, aS. This may be positive or negative, depending on whether the observer is positioned down- or up-slope, respectively, from the tree. The slope angle may be measured, with a clinometer, as the angle from the horizontal to a point on the stem at a height equal to the observer‘s eye level. The distance from the tree to the observer is then measured along the slope. Say the slope distance is s, then the horizontal distance to the base of the tree, d, can be calculated as d = s cos(aS ) (6.3) where ‗cos‘ is the trigonometric expression for the cosine of an angle. Suppose the slope angle was a down-slope of −10° and the slope distance measured was 21.3 m, then the horizontal distance to the tree would be calculated as d = 21.3´ cos (–10) = 21.3´ 0.9848 = 21.0 m. The angle to the tip and base of the tree would be measured as described before and this horizontal distance would then be used in (6.2) to calculate the tree height. On steeply sloping ground and where the observer is standing down-slope of the tree, the angle measured to the base of the tree, aB, may be positive, rather than negative as in Fig. 6.2. This does not affect the computation of height in any way and (6.2) and (6.3) remain appropriate to calculate the height of the tree. The sonic or laser measuring devices described above adjust automatically for ground slope by measuring the angle up or down to the reflector on the tree, which is always positioned at a standard height above ground.

Measurement of height (vertical & leaning) tree in plane and slope areas

Measurement of height of trees on plane area . The height of the tree is calculated with the help of the tangents of the angle to the top and the distance of the observer from the tree.

AB = AD + BD = ED tanα + BD = BF tan α + EF Where, AB = tree, EF = eye height of the observer, BF = horizontal distance

Measurement of height of trees on sloped area . Where the observer is standing at such a place that the top of the tree is above the eye level and the base below it.

AB = AD + DB = ED tan α + ED tan β = ED (tan α + tanβ) = EB Cosβ (tan α + tanβ)

. Where top and base of the tree are above the eye level.

AB = AD-BD = ED tan α – ED tan β = ED (tanα-tan β) = EB cos β (tanα-tan β)

. Where base and top of the tree are below the eye level

AB = BD – AD = ED tan β – ED tan α = ED (tan β - tan α) = EB cos β (tan β - tan α)

. Measurement of height of leaning tree

Case-1(a): In case of the observer standing at between the top and bottom of the tree (lean away from the observer)

exteriorECB  int eriorACB  CBA Therefore

CAB  ECB  CBA  (900 )   900  ( )

Now in triangle AEB,

AB EB  SinAEB SinEAB Therefore, EBSinAEB AB  SinEAB EBSin(   )  Sin[900  (   )] EBSin(   )  Cos(   )

Case-1(b): In case of the observer standing at between the top and bottom of the tree (lean towards the observer) In the triangle ACB, exterior EAB  int eriorACB  ABC  900    900  ( ) Now in triangle AEB,

AB EB  SinAEB SinEAB

Therefore, EBSinAEB AB  SinEAB EBSin(   )  Sin[900  (  )] EBSin(   )  Cos(  ) Case-2(a): When the observer is below the top and bottom of the tree (lean away from the observer)

In the triangle ACB, CAB  exteriorECB  int eriorCBA  900    900  ( ) Now in triangle AEB, AB EB  SinAEB SinEAB

Therefore, EBSinAEB AB  SinEAB EBSin(   )  Sin[900  (  )] EBSin(   )  Cos(  )

Case-2(b): when the observer is below the top and bottom of the tree (lean towards the observer) In the triangle ACB,

exteriorEAB  int eriorACB  ABC 0  90    900  ( ) Now in triangle AEB,

AB EB  SinAEB SinEAB

Therefore, EBSinAEB AB  SinEAB EBSin(   )  Sin[900  (  )] EBSin(   )  Cos(  ) Case-3(a): when the observer is above the top and bottom of the tree (lean away from the observer) In the triangle ACB, CAB 1800 [ACB  ABC ]

1800 [900  ]  90 0  ( )

Now in triangle AEB, AB EB  SinAEB SinEAB

Therefore, EBSinAEB AB  SinEAB EBSin( )  Sin[900  (  )] EBSin( )  Cos(  )

Case-3(b): when the observer is above the top and bottom of the tree (lean is towards the observer) In the triangle ACB, exteriorEAB  int eriorACB  ABC

 900    900  ( )

Now in triangle AEB,

AB EB  SinAEB SinEAB

Therefore, EBSinAEB AB  SinEAB

EBSin( )

 0 Sin[90  (  )] EBSin( )  Cos(  )

Instrument used in height measurement . There are various instruments to measure height of the tree. . Height measuring instruments are called hypsometer. . Those instruments based on trigonometric principles are more accurate than the ones employing geometric principles. . The Abney‘s level, Haga Altimeter, Blume-Leiss Altimeter and Sunto Clinometer are similar in accuracy. a. Christen’s Hypsometer . It is based on the geometric relationships of similar triangles. . Consists of a strip of metal, thin wood or card board about 2.5cm wide and 33 cm length. . It has two flanges or protruding edges one at the top and other at the bottom. . Each flange has a hole in it, the upper one to suspend the instrument by some thread passing through it at and the lower one to suspend a weight from it to prevent it from swinging. . To use it, a pole (usually 5 or 10 ft long) is held upright against the base of the tree, or a mark is placed on the tree at a height of 5 or 10 ft above the ground. . The hypsometer is then held vertically at a distance from the eye such that the two inside edges of the flanges are in line with the top and base of the tree. . It may be necessary for the observer to move closer to or farther from the tree to accomplish this, but except for this, the distance from the tree is immaterial. . The graduation on the scale that is in line with the top of the pole, or the mark, gives the height of the tree. . The following proportion gives the formula for graduating the instrument. A'C' A' B'  AC AB

AC * A' B' AB  A'C' For a given length of instrument A‘B‘ and a given pole length or mark height AC, the graduation A‘C‘ can be obtained by substituting different values of height AB in the equation. Figure: Christen hypsometer . Although the christen hypsometer may be used to measure any type of height, it is practical only for total height measurements. . A crowding of graduations at the bottom of the scale, makes the instrument unreliable for the determination of the height of tall trees. Advantages . It is light, easily made and easy to transport . The height of the tree can be read directly. . It is quicker to use and so it is useful in conditions where speed is required. Disadvantages . Extra care has to be taken to hold the top and bottom of the tree within the flanges while reading the heights. . It should be held in the true vertical plane . It is not suitable for more than 30m tree height. . It requires the use of staff. . Skill is necessary to use the instrument with consistent accuracy. b. Sunto clinometers . Hypsometers based on tangent of angles such as Abney‘s level, Haga altimeter, the Blume-Leiss altimeter and the Sunto clinometers are used in height measurement of trees. . The sunto clinometer is a handheld device house in a corrosion-resistant aluminum body. . A jewel-bearing assembly supports the scale, and all moving parts are immersed in a damping liquid inside a hermetically sealed plastic capsule.

. The liquid dampens undue scale Figure: Sunto clinometer vibrations. . The instrument is held to one eye and raised as lowered until the baseline is seen at the point of measurement. . At the same time, the position of the hairline on the scale gives the reading. . Due to optical illusion, the hairline seems to continue outside the frame and can be observed at the point of measurement. . The instrument is available with several scale combinations: percent and degrees, percent and topographic, degrees and topographic, and feet and meter. . Hypsometers based on the tangents of angle are more accurate than those on similar triangles. . When used correctly, the Suunto Clinometer has an accuracy of about +/- 0.5 m for a 20 m tall tree (ie about 2.5%). Use 1. Measure the horizontal distance from the base of a vertical tree (or the position directly beneath the tree tip of a leaning tree) to a location where the required point on the tree (e.g. tree tip) can be seen. 2. Sight at the required point on the tree: . Using one eye: Close one eye and simultaneously look through the Suunto at the scale and 'beside' the Suunto at the tree. Judge where the horizontal line on the Suunto scale would cross the tree. . Both eyes: With one eye looking at the Suunto scale and the other looking at the tree, allow the images to appear to be superimposed on each other and read where the horizontal line on the Suunto scale crosses the tree. Note: If you suffer from astigmatism (a common situation where the eyes are not exactly parallel), use the one eye approach. 3. Read from the percent scale and multiply this percentage by the horizontal distance measured in step 1. 4. Site to the base of the tree and repeat steps 2 - 3. 5. Combine the heights from steps 3 and 4 to determine total tree height: – Add the 2 heights together if you looked up to the required point in step 2 and down to the base of the tree in step 4. – Subtract the height to the base of the tree from the height to the required point if you are on sloping ground and had to look up to both the required point and the base of the tree. 6. Check all readings and calculations. c. Abney’s level . It is used to measure tree heights as well as land elevations. . The instrument consists of a graduated arc mounted on a sighting tube about 6 inches long. . The arc may have a degree, percentage or topographic scale. . When the level bubble, which is attached to the instrument, is rotated while a sight is taken, a small mirror inside the tube makes it possible to observe when the bubble is horizontal. . The angle between the bubble tube and Figure: Abney's level the sighting tube may be read on the arc. . The abney‘s level, however, is slower to use, and large vertical angles are difficult to measure because of the effect of refraction on observations of the bubble through the tube beneath. . This makes the abney level difficult to use in tall timber that is so dense that the tops cannot be seen from a considerable distance. . When used correctly, the Abney Level has an accuracy of about +/- 0.5 m for a 20 m tall tree (ie about 2.5%). Use 1. Measure the horizontal distance from the base of a vertical tree (or the position directly beneath the tree tip of a leaning tree) to a location where the required point on the tree (e.g. tree tip) can be seen. 2. Sight at the required point and move the index arm over the scale until the bubble tube is level. 3. Read the percentage scale (or the degrees and minutes of the angle). 4. Calculate the height by multiplying the percentage read by the horizontal distance (or by multiplying the horizontal distance by Tan of the angle). 5. Site to the base of the tree and repeat steps 2 - 4. 6. Combine the heights from steps 4 and 5 to determine total tree height: – Add the 2 heights together if you looked up to the required point in step 2 and down to the base of the tree in step 5. – Subtract the height to the base of the tree from the height to the required point if you are on sloping ground and had to look up to both the required point and the base of the tree. 7. Check all readings and calculations. Advantages . It gives accurate angles of elevation and depression . Reading can be taken after sighting the tree without distrubing the index. . It is small and light and can be used even in hills without difficulty. Disadvantages . Shaking of the hand makes the sighting of the top or bottom of the tree a little difficult and time consuming. . The spirit level has to be adjusted by moving the head of the screw while simultaneously looking to the top or bottom of the tree. d. Haga altimeter . It consists of a gravity-controlled, damped, pivoted pointer, and a series of scales on a rotatable, hexagonal bar in a metal, pistol-shaped case. . The six regular American scales are 15, 20, 25, 30, percentage, and topographic scale. . Sights are taken through a gun-type peep sight; squeezing a trigger locks the indicator needle, and the observed reading is taken on the scale. . A range finder is available with this instrument. . When used correctly, the Blume Leiss has an accuracy of about +/- 0.5 m for a 20 m tall tree (ie about 2.5%).

Use Figure: Haga altimeter 1. Select a location, preferably 15, 20, 30 or 40 meters horizontal distance from the base of a vertical tree (or the position directly beneath the tree tip of a leaning tree) where the required point on the tree (e.g. tree tip) can be seen. 2. Select the appropriate distance scale on the rotating rod. 3. Release the pointer by pressing the button on the side of the instrument. 4. Sight at the required point on the tree, wait for a moment for the pointer to settle then pull trigger. 5. Read the height directly from the appropriate scale if you are 15, 20, 30, or 40 meters away from the tree. If you were unable to find a position at one of these distances: – If the horizontal distance is a simple fraction of one of the scale distances (e.g. 10 m is half of 20 m), read from the scale distance and multiply by the appropriate fraction. – Read from the percent scale and multiply this percentage by the horizontal distance measured in step 1. 6. Site to the base of the tree and repeat steps 3 - 5. 7. Combine the heights from steps 5 and 6 to determine total tree height: – Add the 2 heights together if you looked up to the required point in step 2 and down to the base of the tree in step 6. – Subtract the height to the base of the tree from the height to the required point if you are on sloping ground and had to look up to both the required point and the base of the tree. 8. Check all readings and calculations. e. Spiegel relaskop . The Spiegel Relaskop, also known as a Relaskop, is a sophisticated instrument that can be used to measure stand basal area and tree height and diameter at any point up a tree bole. . In conjunction with other equipment, the Relaskop can be used in the estimation of distance

Figure: Spiegel relaskop (range) to an object and the number of trees / ha. . The Relaskop has a peep-hole at the rear and a clear window at the front. . Three additional windows in the lower half of the instrument allow light to enter and illuminate the scale. . A brake button, bottom half at the front of the instrument, allows a weighted wheel within the Relaskop to rotate. . When looking through the peephole, a circular field of view is seen. . The scales are seen in the bottom half of this field of view and scale readings are taken where the scale touches the line halfway up the field of view. . The standard metric Relaskop has three scales for measuring (vertical) height. The appropriate scale will depend on the horizontal distance from the tree. – left-most scale - 20 m from the tree. – middle-left - 25 m from the tree. – middle-right - 30 m from the tree. . If you depress the brake button and look straight up or down, the appropriate distance values can be seen alongside their scales. . Select a point from where base and tip (or any other points of interest) must be clearly visible from the selected point.

Figure: Scales in Spiegel relaskop

f.Blume Leiss altimeter . It is similar in construction and operation to the Haga altimeter, although its appearance is somewhat different. . The regular scales are 15, 20, 30 and 40. A degree scale is also provided. . All scales can be seen at a time. The instrument is available with a rangefinder. . When used correctly, the Blume Leiss has an accuracy of about +/- 0.5 m for a 20 m tall tree (ie about 2.5%). Use 1. Select a location, preferably 15, 20, 30 or 40 meters horizontal distance from the Figure: Blume leiss altimeter base of a vertical tree (or the position directly beneath the tree tip of a leaning tree) where the required point on the tree (e.g. tree tip) can be seen. 2. Release the pointer by pressing the button on the side of the instrument. 3. Sight at the required point on the tree, wait for a moment for the pointer to settle then pull trigger. 4. 4. Read the height directly from the appropriate scale if you are 15, 20, 30, or 40 meters away from the tree. If you were unable to find a position at one of these distances: – If the horizontal distance is a simple fraction of one of the scale distances (e.g. 10 m is half of 20 m), read from the scale distance and multiply by the appropriate fraction. – Read from the percent scale and multiply this percentage by the horizontal distance measured in step 1. 5. Site to the base of the tree and repeat steps 2 - 4. 6. Combine the heights from steps 4 and 5 to determine total tree height: – Add the 2 heights together if you looked up to the required point in step 2 and down to the base of the tree in step 5. – Subtract the height to the base of the tree from the height to the required point if you are on sloping ground and had to look up to both the required point and the base of the tree. 7. Check all readings and calculations

g. Vertex IV and Transponder T3

The vertex is primarily designed to measure the height of standing objects, and most often trees. The instrument can also be used to measure distance, horizontal distance, angle and inclination. The vertex instrument has with its ultrasonic measuring technique proved to be especially useful in dense Figure: Vertex terrains with thick undergrowth, where conventional methods such as measuring tapes, laser instruments and mechanical height measurers are difficult to use.

To define a reference point is a secure and reliable way, the vertex works with the transponder. The vertex communicates with the transponder. This communication eliminates in an efficient way any mix-ups of signals from other instruments or places (echoes). A measuring operation will not in any significant way be disturbed by objects in between the vertex and the transponder. This reference is used as a sight mark for height measuring and can be placed at optional Figure: Transponder 3 height, where visibility is the best in for example thick vegetation. The reference point height is set in a special menu in the vertex instrument and automatically added to the measured height.

The vertex uses ultrasound to measure distances. Unlike for example measuring tapes and laser instruments, ultrasound can be used also when there is no free aim to the reference point. The ultrasound will not pass through an obstacle, but looks for the shortest way around it.

Heights are calculated trigonometrically using the variables contained when measuring angle and distance. The vertex automatically assumes that the measuring object is perpendicularly positioned to the ground.

With the vertex, an unlimited number of heights per object can be measured. The instrument display can show the 4 lastly measured heights per object at a time.

When using a relaskopic method to measure, an in built BAF (Basal Area Factor) can be used for the vertex instrument to control the minimum diameter for trees. The function is useful when some trees in an area are covered by other, making the decision whether to include the tree or to exclude if from the area difficult. By simply measuring the distance between the tree and the plot centre, the vertex can calculate the minimum diameter the tree should have in order to be included into the counting.

Data can be sent through IR or Bluetooth and results can be stored and processed in for example the Digitech Professional Caliper, other PC or handheld computer.

Important facts

The Vertex uses ultra sonic signals to determine distances. Humidity, air pressure, surrounding noise and, above all, the temperature can affect the range and extension of the ultra sonic signals. The Vertex has a built-in temperature sensor that automatically compensates for the divergence caused by variations in temperature. In some cases, distances of 50 meters and greater can be measured without problems, and in other cases, the maximum distance can be shorter than 30 meters.

To increase and optimize the measuring accuracy, calibration should be made regularly. When calibrating, it is of utmost importance that the instrument has been given enough time to stabilize at ambient temperature. If, for example, the instrument is carried in an inner pocket, it can take up to 10 minutes before it has adjusted to current outdoor temperature. The measurement inaccuracy pending on temperature is approximately 2 cm/C°.

An example: Your inner pocket holds +15 C°. Outdoor air temperature is -5 C°. The measurement result will show 10,40 m and not the correct 10,00 m.

The measuring fault can be made permanent if the instrument is calibrated before reaching the correct current temperature. -Check your instrument daily and recalibrate if necessary -Do not touch the temperature sensor at the front of the instrument (the metal knob between the sight and the loudspeaker) -Never calibrate the instrument before it has reached ambient temperature

When measuring heights, it is important to hold the instrument as straight as possible. The trigonometric functions calculate the height based on two (2) angles and one (1) distance. The distance can be measured manually with a tape, or automatically by using the Ttransponder. If using a tape, the distance has to be input in the Vertex before starting (angle-) and height measuring.

How to use the Vertex HEIGHT Height measuring can be performed in different ways depending on type of surroundings and operation. Heights, distance and angle can be transmitted via InfraRed (IR) to, for example the Digitech Professional Caliper or other computer device for storage/processing with IR or Bluetooth (Vertex IV BT model only) by pressing right arrow key. For height measuring 3 last measured heights with angle and distance can be transferred.

Height measuring with transponder Start the transponder and place it on/towards the object to measure. Note that the transponder should be placed at the T.HEIGHT /(transponder height) that has been set in the settings menu. Walk a suitable distance from the object – for optimal results the distance equals the approximate height. 1. Press ON to start the Vertex and aim at the transponder. Keep pressing ON until the cross hair sight goes out momentarily. Now release ON. The Vertex has measured the distance, the angle and the horizontal distance to the transponder. 2. Aim at the height to measure with the sight cross blinking. Press ON until the cross hair disappears. The first height is locked and displayed. Repeat until all heights on the object are measured.

Inclination (ANGLE) The Vertex is an excellent instrument to measure inclination and angles in the terrain. 1. Press ON to start the Vertex and step with the arrow keys to ANGLE and press ON. 2. The angle window is displayed. Aim at the point where you need to know the angle. Push and press the ON until the cross disappears. Read the obtained value in display. The angle is featured in Grads, degrees and percentage. Note that the angle is measured from the Vertex with the cross hair sight. This implies that it is not possible to use the outside of the Vertex to measure the angle of, for example a flat table surface.

Distance Measuring (DME) To measure the distance, press the DME key (left arrow key) when the vertex is turned off. The result, the distance between the vertex and the transponder, is presented in the vertex display.

Distance measuring with the adapter for 360 degrees With the adapter, the ultrasound is spread and it is possible to measure from any direction. This is particularly useful when working in circular sample plots, where the distance from the plot centre to objects within a defined circle should be measured.

Horizontal distance measuring (DME) The vertex can be used as horizontal distance measurer (DME). The Figure: Transponder with adapter display text will rotate 900 to simplify reading the results when measuring horizontal distances. 1. Press ON to start the vertex and go with the arrow keys to ANGLE and push ON. 2. Aim at the point where you need to know the angle. Push and press the ON until the Red Cross goes out. 3. To measure the distance, now push the left arrow key. The vertex presents the horizontal distance in the display.

Basal Area Factor Working in dense forest with relaskopes or prism can sometimes offer difficulties and accurate diameter estimation hard to make. When using relaskopic method to measure, an in built BAF function can be used for the Vertex instrument to control the minimum diameter for trees. The function is useful when some trees in an area covered by other, making the decision whether to include the tree or to exclude if from the area difficult. By simply measuring the distance between the tree and the plot centre, the vertex can calculate the minimum diameter the tree should have in order to be included in the counting. Basal area factors: 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 (m2/ha) Transponder The transponder is an ultrasonic transmitter/receiver that communicates with the vertex instrument. The transponder can be used both for direct measuring (600), and in 3600 when used with ―360 adapter‖- for example when working in circular sample plots. The transponder is equipped with an audible signal that tells if the transponder is activated or not. Transponder T3 has no switch and the vertex and /or DME is used as a remote control to turn off and on. When turned on, the transponder stays activated for app. 20 minutes. To measure in 3600 circle with the transponder, the T3 is attached to the adopter. The adapter spreads and receives the ultrasound in a full circle. The adapter can be mounted onto the custom plot center staff.

Special considerations in measuring tree heights . It is difficult to measure accurately the height of large flat crowned trees. There is tendency to overestimate their heights. . The optimum viewing distance for any hypsometer is the distance along the slope equal to the height to be measured. This rule of thumb should be used with discretion. . Since all hypsometers assume that trees are vertical, tress leaning away from an observer will be underestimated and trees leaning towards an observer will be overestimated. This error will be minimized if measurements are taken such that the lean is to the left or right of the observer. . The measurement of tree height with an accurate hypsometer is slow and expensive.

Sources of errors in height measurement . Measuring the height of trees is time consuming and prone to errors. . Experience has shown that when indirect methods are used to measure height, measurement from two independent positions is essential. . The readings from the two positions should agree within the limits of instrumental error - this is an absolute check on instrument and operator error (sighted to correct tip, etc.). . Thus, differences of up to 1 m in readings for a 40 m tree are acceptable - precision of instruments under forest conditions is no better than this. The most common errors include: . The sources of the major errors in height measurement are: 1. Failure to measure correctly the horizontal distance from the observer to the tree If the distance from the observer to the tree is not measured horizontally, the observer will stand too near the tree, and the height will be overestimated by the direct reading on the instrument scale. 2. Wind sway Wind causes tree tops to sway and this can be very serious hindrance in tree height measurement and cause serious errors. Accurate readings cannot be made in high winds. The errors may be reduced by averaging readings taken at the extremes of the sway towards and away from the observer. 3. Leaning trees If the tree is leaning away from the observer, height will be under estimated and if the lean is towards the observer, height will be overestimated. 4. Non linearity of the relationship of tree height and angle of sight. The smaller the angle of the sight the easier it is to define the highest point in the crown; but the nearer the angle of sight to 450 the smaller is the error caused by an inaccurate reading of that angle. The best compromise between these two conflicting considerations is to select the observation point so that the angle of sight lies between 300 and 450, i.e the observer should stand between one and one-and-a-half times the tree height away from the tree. Angles greater than 450 must be avoided as the probability of mistaking a side branch for the top of the tree is unacceptably high. 5. Instrument error. All instruments should be checked periodically against some standard or known height and adjust as necessary. 6. Operator and recording error. - Personal error is always likely, e.g. – incorrect setting of distance or booking of angles and distances, incorrect reading; – forgetting to add on the section of tree below eye level or forgetting to sight to the tree base; – Measuring to wrong tip - shaking the tree may help! – Difference of opinion amongst observers in nominating the tip of an umbrageous crown.

Chapter 7 Tree stem form, form factor, form quotient, measurement of volume of felled and standing trees, age determination of trees

Tree Stem Form . Form is the rate of taper of a log or stem . It is the decrease in diameter of a stem of a tree or of a log from base upward. . The taper varies not only with species, age, site and crop density but also in the different parts of the same tree. . The basal portion of the tree corresponds to the frustum of a neiloid, the middle portion to the frustum of a paraboloid, and the top portion to the cone . Trees often are combinations of form.

Metzger’s Theory or Girder Theory

. Several theory put forward to explain variations in taper from tree to tree and in the same tree as well . Metzer‘s theory assumes that the tree stem should be considered as a cantilever beam of uniform size against the bending force of the wind. . The wind pressure acts on the crown and is conveyed to the lower parts of the stem in an increasing measure with the increasing length of the bole. . Thus, the biggest pressure is exerted at the base and there is a danger of trees snapping at the place, to counteract this tendancy, the tree reinforces itself towards the base. . The pressure of wind crown keeps on changing as the tree is growing in open crowded portion. . Tapering increase if it is an isolated area, an area where largest density, in the area tapering decreases. . Though tapering is the natural process which can be controlled by human interference. If competition increases, tapering decreases. . Trees growing in complete isolation or exposed situation have short but rapidly tapering boles while the trees growing in dense crops, which are therefore subjected to lesser wind pressure, have long and nearly cylindrical boles. Mathematically, Let, p= a force applied to a cantilever beam at its free end l= the distance of a given cross section from the point of applications of this force d= the diameter of the beam at the point s= the bending stress in kg/cm2

By the rule of mechanics,

p*l 32 S  * d 3 

As the force p in case of trees consists of components W= wind pressure per unit area, F= crown area, than p=w*F Then, w* F *l 32 s  * d 3  32 * w* F *l d 3   * s . For a given tree w, F, s can be considered as constant, therefore d3= kl, where k is a constant . Thus, the diameter raised to the third power increases proportionately with lengthening of the lever or with the increasing distance from the central point of application of wind force . According to this logic, the tree stem must have the shape of a cubic paraboloid.

Methods of studying form 1. By comparisons of standard form ratios (form factor and form quotient) 2. By classification of form on the basic of form ratios and 3. By compilation of taper table

Form factor and its type . Form factor is the ratio of the volume of a tree or its part to the volume of a cylinder having the same length and cross section as the tree. . It is the ratio between the volume of a tree to the product of basal area and height.

V F  Sh Where, F  form factor

V  tree volume in cubic units

S  basal area at breast - height in area units h  height of the tree in linear units Types of form factor

1. Artificial form factor

. Known as breast-height form factor . Basal area or diameter measured at dbh and the volume refers to the whole tree both above and below the point of measurement. . It is not reliable guide to the tree form. . Diameter measurement is fixed, but no fixed relation exists to the height of the tree and portion above the breast height. . Trees of same form but different heights will have different form factor. . Universally used for its handy measurement and standardization of diameter at breast height. . A useful application is for quick-and-dirty volume estimates, assuming a constant form factor.

2. Absolute form factor

. It is the ratio between the volume of the tree above the point of diameter or basal area measurement with the cylinder which has the same basal area and whose height is equal to the height of the tree above that point. . Basal area is measured at any convenient height and the volume refers to that part of the tree above the point of measurement.

3. Normal form factor

. Basal area is measured at a constant proportion of the total height of the tree, e.g 1/10th , 1/20th etc. of the total height and the volume refers to the whole tree above ground level.

Disadvantages 1. The height of tree to be determined before the point of measurement can be fixed. 2. Point of measurement very inconvenient in case both very tall and short trees. Absolute form factor and normal factor are no longer used. Unless stated, form factor implies artificial form factor whose basal area calculated at 1.3 m. The natural form factor corresponding to the total volume of a stem is generally between 0.3 and 0.6.

Uses of form factor 1. To estimate volume of standing trees . Form factor compiled in tabular form to give average form factor of different dimensions by dbh and height classes. . Table used to estimate volume by measuring dbh and height. . Table prepared from measuring large number of trees, so application to individual tree not satisfactory, however used to estimate volume of group trees. . Uses limited to similar growing conditions 2. To study laws of growth . Gives insight to laws of growth, particularly to stem form of trees.

Kinds of form factor Depending upon volume represented, form factor may be of following kinds 1. Tree form factor 2. Stem timber form factor 3. Stem small wood form factor Form Height It is the product of form factor and total height of the tree. V Fh  S Where,

Fh  form height V  volume of the tree S  basal area Volume is calculated from under bark measurements and the basal area is calculated from dbh (ob). Form height is used to determine how far is it reasonable to assume that volume is proportional to the basal area. If form height remains constant with increasing diameter, then it is clear that the assumption is justified. Form quotient and its type Form Quotient

. It is the ratio between the mid-diameter and the dbh. mid -diameter F.Q  dbh

. Taper depends upon form quotient (A. Schiffel) Types of form quotient

1. Normal form quotient . Ratio of mid-diameter or mid-girth of a tree to its diameter or girth at breast height. 2. Absolute form quotient . Ratio of diameter or girth of a stem at one half its heights above the breast height to the diameter or girth at breast height.

Form quotient is the third independent variable of volume table that can be used to predict the volume of a tree stem.

Form Class . Form class is defined as one of the intervals in which the range of form quotients of trees is divided for classification and use. . It also implies to the class of trees which fall into such an interval. . Trees may be grouped into form classes expressed by form quotient intervals such as 0.50 to 0.55, 0.55 to 0.60 and so on or by mid-points of these intervals such as 0.525, 0.575 and so on.

Form Point Ratio . It is defined as the point in the crown as which wind pressure is estimated to be cantered. . Form point ratio is defined as the relationship, usually expressed as a percentage, of the height of the form point above ground level to the total height of the tree. . Form point ratio bears a consistent relation to the form quotient. . If form point ratio is known, the form quotient and form class of a tree can be determined.

3.3 Taper table and formulae . It provides the actual form by diameters at fixed points from the base to the tip of a tree. . Volume tables can thus be prepared from taper tables in desired unit.

Use of taper table 1. Volume of the average tree for each diameter and height class can be found readily in office without direct measurement. The only measurement that will be needed is the dbh (ob) and the height of standing tree. 2. Volume table can be prepared from taper tables in desired units. The ultimate purpose of all taper tables is to show upper stem diameters, which can then be used to calculate the volume of the sections of a tree and the entire tree. Taper tables can assume several forms. Types of taper table 1. Ordinary taper table or diameter taper table . It gives the taper directly for diameter at breast- height without reference to the tree form. 2. Form class taper table . This tables gives for different form classes the diameters at fixed points on the stem expressed as percentage of dbh (u.b)

General formulae or equations for tree form . Taper equation represent the expected diameter as a function of height above ground, total tree height and dbh irrespective of tree species and generalized for form class . Many different forms of taper equations have been developed as no single one can adequately represent all species in all situations. The use of taper equations allow us to obtain volumes for any desired portion of a tree stem by predicting upper stem diameters.

Hojer’s formulae . It determines the diameter quotient (i.e the ratio of the diameter of a stem at any given height to its breast-height diameter) for each form class . It gives the percentage of the length of the tree between breast height and top

d c  l  C log dbh c Where , d  Diameter at any point on the stem

C & c  Constant for each form class

l  Distance from the top of the tree to the point at which d is measured

Behre’s formulae d 1  dbh a  b

Where , d  Diameter at any point on the stem a & b  Constant for each form class, a  b  1

l  Distance from the top of the tree to the point at which d is measured

. This formulae is more consistent Bark Measurement . The thickness of the bark and its percentage of volume in the tree or log are important parameters in mensuration because most measurements on standing trees have to be made on over bark. . Some species have very thick bark. In general, bark thickness varies with: species, age, genotype, rate of growth and position in the tree . The bark thickness of the living tree may be measured with little damage to the trees using a Swedish Bark Gauge Vob Vub Bark Percent  *100 Vob Where,

V  Volume over bark ob V  Volume under bark ub

Measurement of log volume of trees: Some terminology Basal area: the area of a cross section of a stem at breast height Billet: A piece of round wood about one meter in length usually cut for pulp or firewood Cull: the portion of a tree stem or log which is unmerchantable Log: The stem of a tree or a length of stem or branch after felling and trimming (BCFT)

Measurement of length, diameter and sectional area of logs . The ultimate object of all mensuration activity in forest is to calculate or estimate quantity of wood contained in trees and consequently in crops not only for sale but also for research, predicting future yields, estimating increment to assess return on capital etc. . Measurement of felled trees are to determine the quantity of merchantable volume to obtain statistical data that could be applied to standing trees for the purpose of estimation the yield, to estimate the growing stock and to estimate the increment of woods and forests. . Volume estimation may be made most accurately when the logs are separated and accessible to the measurer . A tree, therefore, could be separated into stem wood, which may be further divided into timber and small wood, crown and branch wood. . Stem wood may be measured after division into sections for obtaining real volume . The measurement requires length and mid diameter or mid girth except where the tip is measured as frustum of a cone where the diameter or girth at the ends is measured. . Logs are neither cylinder nor often of any regular geometric shape. Therefore in order to calculate the volume, the shape of a quadratic paraboloid is adopted. . It is usual to cut the tree into logs due to irregularity in tree tapers. . The length of the logs depends upon the rate of taper and market requirements. . As the diameter at the thin end of the log determines the sawn volume that can be taken out of it, the greater the rate of taper, the lesser is the length of the log. . Another consideration that affects the length of log is the mode of transport . When the logs are made for calculating volume of felled trees for research work, all logs including the first are of uniformly 3m in length except the top end log which may be up to 4.5 m. But if the end section is more than 1.5m in length, it is left separate rate log. . Simple tape or a graduated rod can be used to measure the length of a given logs. . Similarly, diameter tape, caliper and other optical instrument are used to measure the diameter and sectional area of logs. . Logs ate the round piece with square cut ends./Normally, a log is 6 or 8 ft over in length and suitable for . . The cross sectional area or basal is found from the diameter as follows:

d 2 BasalArea  4 Formulae for log volume calculation When calculating volumes of logs and trees we normally assume that the sections are circular, or at least that diameters are such that the area of the section is πD2/4. It is customary in forest mensuration to take the shape of logs and trees as similar to certain solids of revolution, the cylinder, paraboloid, cone, or neiloid.

More generally, different parts from the tree resemble portions of these solids. The crown part, in conifers, tends to the cone form. The stem central part approaches a paraboloid. The base of the tree expands in a form similar to the neiloid, although generally values of n greater than 3 come closer.

A. Prismoidal or Newton’s formula

S  4S  S V  1 m 2 *l 6 Where, V  Volume of Logs

S1  the sectional area at the thick end

S  the sectional area at the middle m S2  the sectional area at the thin end l  the length or height of the solid . It is the best and accurate method for volume calculation . It gives particularly the volume of frustum of Neiloid ( as well as other sections) . It is only used to calculate the error in volume calculated by other formula . It is difficult to apply particularly when the logs are stacked

B. Smalian’s formula S  S V  1 2 *l 2 Where,

V  Volume of Logs

S  the sectional area at the thick end 1

S2  the sectional area at the thin end l  the length or height of the solid

. It gives the volume of frustum of paraboloid ( also cylinder) . It over estimates the volume . It is used when the logs are stacked or lying on the ground

C. Huber’s formula

V  Sm *l Where, V  Volume of Logs

Sm  the sectional area at the middle

l  the length or height of the solid

. It gives the volume of frustum of paraboloid ( also cylinder) . It under estimates the volume . It is difficult to apply particularly when the logs are stacked. . It is more easy and accurate than Smalian‘s formula D. Quarter Girth formula (Hoppus’s rule) 2  g  V    *l  4 

Where,

V  Volume of Logs

g  the girth of the log at the middle l  the length of the log . This is the system of measurement used in Great Britain and also in Nepal for sale purpose when round timber is sold by volume . This formula gives only 78.5% of the cubic volume of cylinders, thus allowing a loss of 21.5% Volume of sawn timber

Figure: Sawn timber

. It is the simple product of three dimensions; length, breadth and height . Volume of sawn timber varies according to its cross sectional size and length.

2.3.3 Volume of stacked timber . Products such as firewood and pulp logs are frequently commercialized according to their volume in piles or stacks. . A stere metre is the volume of a stack of 1×1×1 metres (a cubic metre stacked), and it is used for firewood . This volume contains air space and wood in variable proportions according to the form of logs . Piling co-efficient has to be used to get the actual volume . Piling co-efficient= π/4=0.7854 if all piece of wood were cylindrical and of the same diameter Figure: Stacked timber . Due to edge effects the wood content can vary slightly with the stack dimensions, and much with the stacking method, so buyers and sellers usually establish specific norms on dimensions and stacking methods. . Other important factors in the solid content are the irregularity of the logs, the variability of the diameters, and the bark thickness. . Movement during transport can also introduce important changes.

2.3.4 Dimension and volume of chatta (stacked fuelwood)

Figure: Chatta

. Standard size of chatta= 5ft.*5ft. *20ft. = 500 cft including air space . One chatta in metric unit= 14.16m3 . The following formula should be used in order to calculate the amount of fuelwood that is obtained from the total volume up to 10 cm top-diameter of class III and the remaining portions up to 10 cm top-diameter of class I and II trees which would not be used as timber.

Volume of chatta  0.8778*Vol.I1.4316*Vol.II3*Vol.III Amount of fuelwood in terms of number of chatta  1000

Where,

Vol.Igross volume of up to 20 cm top diameter of class I trees

Vol.IIgross volume of up to 20 cm top diameter of class II trees

Vol.III  gross volume of up to 10 cm top diameter of class III trees

. All trees except Khair having dbh of 27.94 cm (11 inch) or above should be classified as below Class I = Green, dead or dying, standing or uprooted tree having good and solid trunk in which sign of any disease or wound is not visible from outside Class II = Green, dead or dying, standing or uprooted tree in which complete volume could not be realized due to hollowness or other sign of defect but at least two straight logs of each 1.83 m (6ft) long or one straight log of 30.5 m (10 ft) long which should have at least 20 cm diameter could be recovered. Class III = Remaining trees which do not fall under class I and class II

Solid volume of fire wood . The stacked volume is not the actual volume of firewood, it is only for the convenience of paying the labour in the forest where there is no arrangement for weightage. . Solid volume of firewood in a stock depends upon several factors such as care in stacking, form of billets, length of billets and their diameter (i) Xylometric method . Volume of billets calculated with the help of xylometer which consists of a graduated vessel . Volume of wood calculated by the principle of water displacement . Water poured in vessel, reading taken, wood are submerged in water and reading taken again. . Difference between two reading gives the volume of submerged wood

For large quantities of wood If ,

W  Weight of whole stack of wood w  Weight of submerged pieces V  Volume of the whole stack of wood

v  Volume of submerged pieces

W : w  V : v

W * v V  w . This method is cumbersome and seldom used in practice

(ii) Specific gravity method . Specific gravity is a unitless measure of mass. . If specific gravity of wood is known than volume can be calculated. Weight of wood Specific gravity of a piece of wood  Weight of same volume of water

Density of wood Specific gravity of a piece of wood  Density of water Weight (gms) Volume  cc Specific gravity

. As density for pure water is 1 gm per cc, the density of wood in gm per cc is the same as its specific gravity minus the units. . Specific gravity typically varies from 0.35 to 0.81 for most commercial tree species

Tree age: Without specific information, determining the actual age of a standing, live tree is difficult. If you know when the tree was planted, you can easily and accurately determine its age. The second most accurate way to estimate tree age is to count the annual rings of wood growth. Annual rings can be counted using two different methods. You can extract an increment core from the tree using an increment borer. Most people, however, do not have access to an increment borer, and in fact this instrument does result in an injury to the tree. For trees that are dead and have been cut down, you can count the rings on the stump. This provides an accurate estimate, but for live trees it just won‘t work! However, you can estimate the age of a living tree, without knowing when the tree was planted, by the following method. In the example below, we are measuring a very large white oak tree. STEP 1. Measure the circumference (c) of the tree trunk using a measuring tape that measures in feet and inches. This should be done at 4.5 feet above the ground. EXAMPLE: Our white oak tree measures 12 feet, 10 inches in circumference. c = 12 feet, 10 inches = 154 inches (multiply 12 feet x 12 inches per foot, then add 10 inches) STEP 2. Calculate the diameter (d) and radius (r) of the trunk in inches. Divide the circumference by 3.14, a constant known as ―pi‖. c/3.14 = d 154 inches/3.14 = 49 inches Divide the diameter by 2 to get the radius. d/2 = r 49 inches/2 = 24.5 inches  The trunk diameter is the width of the cross section of the trunk directly through the middle. The radius is the distance from the center of the tree out to the bark.  Measure completely around the trunk at 4.5 feet above ground to get the circumference. NOTE: You should deduct at least .5 inch from the radius for the width of the tree‘s bark, and more for trees with very thick bark (1.0 inch), less for trees with very thin bark (.25 inch). In our example, we will deduct .5 inch, for a radius of 24 inches. While you will use the radius to calculate tree age, the trunk diameter of a tree is a commonly used measurement. The trunk diameter measured at 4.5 feet above the ground is officially known as ―diameter at breast height‖, or ―dbh‖. STEP 3. Determine the average width (w) of an annual ring of wood for the species of tree you have measured. In ring-porous species of trees (distinct annual rings), the annual ring will contain both early or spring wood (large vessels) and late or summer wood (small vessels). In diffuse porous woods, it is much more difficult to see where the rings begin and end. A hand lens or magnifying glass is useful. The width of an annual ring of wood for a particular species depends upon many factors, including:  Genetic differences  Tree age  Height above ground  Local site and climatic conditions  Competition from other trees  Water availability  Nutrient availability  Presence of insects or diseases  General tree health You can also calculate the average width of an annual ring using cross sections of wood from the same species. Measure the radius from just inside the bark to the center of the trunk, count the number of rings, and divide the radius by the number of rings. The result will be the average width per ring. 10 inches/50 rings = .2 inches/ring Conversely, if we divide the number of rings by the number of inches, the result will be the average number of rings per inch. 50 rings/10 inches = 5 ring/inch If the absence of actual data for white oak we will use in our example an assumed average of .2 inches per ring, or 5 rings per inch. STEP 4. Divide the radius (r) by the average width (w) of one annual growth ring to get the approximate age of the tree. r/w = approximate age 24 inches/.2 inches per year = 120 years! An age of 120 is relatively young for a white oak. Under perfect conditions, a white oak tree can live to be 300 or more years old. However, under urban conditions, most white oak trees will only live to be around 150 years old. Many of our other common oak trees, such as water, willow, northern red, and southern red oak live to be about 80-100 years old under urban conditions. Another one of our more common trees, flowering dogwood, is a very old tree when it is around 50 years old.

MEASUREMENT SYSTEMS There are 2 most important systems of measurement i.e. (i) British or Imperial and (ii) Metric systems. Conversion of Measurement Units a) Conversion factors for linear measures 1 inch = 2.54cm 1 cm = 0.3937 inch 1 foot = 30.48cm 1 m = 39.38 inches 1 yard = 91.44cm 1 m = 3.2808 feet 1 mile = 1.6093km 1 m = 1.0936 yards 1 km = 0.6214 mile b) Conversion factors for square measures 1 sq. inch = 6.4516cm2 1cm2 = 0.1550 sq. in. 1 sq. foot = 0.0929m2 1m2 = 10.764 sq. ft. 1 acre = 0.40469ha 1 ha = 2.471 acres 1 sq. mile = 2.59 km2 1km2 = 247.1 acres 1km2 = 0.3861 sq. mile c) Conversion factors for cubic measures 1 cu. m = 16.387cm3 1cm3 = 0.610 cu. in. 1 cu. ft = 0.2832m3 1m3 = 35.314 cu. ft. 1 cu. yd. = 0.764553 1m3 = 1.308 cu. yd d) Conversion factors for weight measures 1 oz = 28.35g 1 g = 0.0252 oz 1 ib = 453.60g 1 kg = 2.205 lbe. 1 qtr = 12.701 kg 1 cwt = 50.802 kg

Chapter 8 Agroforestry – definitions, importance, criteria of selection of trees in agroforestry, different agroforestry systems prevalent in the country Introduction: Trees play an important role in ecosystem in all terrestrials and provide a range of products and services to rural and urban people. As natural vegetation is cut for agriculture and other types of development, the benefits that trees provide are best sustained by integrating trees into agricultural system — a practice known as agroforestry. Farmers have practiced agroforestry since ancient times. Agroforestry focuses on the wide range of trees grown on farms and other rural areas. Among these are fertilizer trees for land regeneration, soil health and food security; fruit trees for nutrition; fodder trees for livestock; timber and energy trees for shelter and fuel wood; medicinal trees to cure diseases and trees for minor products viz. gums, resins or products. Many of these trees are multipurpose, providing a range of benefits. According to the 2001 report of the , the forest cover in the country is 675,538 sq.km, constituting 20.55% of its total geographical area. Out of this, dense forest constitutes 2.68% and open forest 7.87%. The forest cover in the hilly districts is only 38.34% compared with the desired 66% area. The National Agriculture Policy (2000) emphasized the role of agroforestry for efficient nutrient cycling, nitrogen fixation, organic matter addition and for improving drainage and underlining the need for diversification by promoting integrated and holistic development of rainfed areas on watershed basis through involvement of community to augment biomass production through agroforestry and farm forestry. The Task Force on Greening India for Livelihood Security and Sustainable Development of Planning Commission (2001) has also recommended that for sustainable agriculture, agroforestry may he introduced over an area of 14 million ha out of 46 m ha irrigated areas that are degrading due to soil erosion, water-logging and salinization. For integrated and holistic development of rainfed areas, agroforestry is to be practiced over an area of 14 million ha out of 96 m ha. This all will, besides ensuring ecological and economic development provides livelihood support to about 350 million people. The practice of agroforestry can help in achieving these targets. Therefore in the quest of optimizing productivity, the multi tier system came into existence. Gap of demand and supply of forest produce in India is widening and forests are unable to fulfill the demand. Agroforestry can play an important role in filling this gap and conservation of natural resources.

Table 1: Demand and supply of different tree produce in India

The origin of agroforestry practices, i.e. growing trees with food crops and grasses, is believed to have been during Vedic era (Ancient period, 1000 BC) the agroforestry as a science is introduced only recently. The systematic research in agroforestry geared up after the establishment of the International Council for Research in Agroforestry (lCRAF) in 1977, which was renamed in 1991 as the International Centre for Research in Agroforestry. During 2001-02, ICRAF adopted a new brand name "World Agroforestry Centre", to more fully reflect their (ICRAF's) global reach and also their more balanced research and development agenda; however their legal name "International Centre for Research in Agroforestry" will remain unchanged. In India, organized research in agroforestry was initiated in 1983 by the establishment of All India Coordinated Research Project on Agroforestry by ICAR at 20 centres and later establishment of the National Research Centre for Agroforestry at Jhansi in 1988. At present 39 centres of agroforestry are working in the country. The process of system evolution can be still observed in the natural forests through settled agriculture, animal husbandry and organized forestry with the adoption of variety of land use practices where tree is one of the components. Agroforestry systems have been the target of scientific enquiry and analysis and thus have been defined by many in different ways. What Is Agroforestry? Agroforestry is a unique land management approach that intentionally blends agriculture and forestry to enhance productivity, profitability, and environmental stewardship. Agroforestry can be a key tool for farmers, ranchers, woodland owners, communities, and others who want to use sustainable strategies that enhance agricultural practices and protect natural resources. Agroforestry opens new opportunities to create prosperity while providing vital protection to natural resources by supporting: • sustainable farms, ranches, and woodlands • diversified income on farms and ranches • clean air and water • habitat for wildlife • improved soil health • safe and healthy food • energy conservation • bioenergy production • increased wealth in rural communities Agroforestry practices can resemble a living patchwork quilt across entire watersheds. For instance, managed forest canopies in a woodland can protect a range of crops grown for food, landscaping, and medicinal use–plants such as shiitake mushrooms, ramps, ginseng, goldenseal, curly willow, and sword fern. Additionally, farmers and ranchers who plant pine trees on land used for livestock and forage production can add to their profits by selling pine straw and high-value sawlogs. This is agroforestry…combining trees and agriculture to enhance long-term production of food and other useful products while protecting the soil and water, diversifying and expanding local economies, providing wildlife habitat, and ensuring a more pleasing and healthy place to work and live.

Definition of Agroforestry Agroforestry is a form of natural-resource management that plays a key role in a wide range of situations from providing important income-generating tree products and crops for land users in areas with developed markets to reclaiming degraded lands. According to the definition currently used by ICRAF, agroforestry .refers to a dynamic, ecologically based, natural resources management system that, through the integration of trees in farms and in the agricultural landscape, diversifies and sustains production for increased social, economic and environmental benefits for land users at all levels. (ICRAF 1996).

Two missionaries, Danforth and Noren (1994), suggested another definition of agroforestry: .Agroforestry is an ancient farming system established by God when he created the Garden of Eden (Genesis 1 and 2). In Eden, God had every kind of plant and animal in association with trees for the benefit of people.s survival and pleasure.. Agro forestry, the word coined in early seventies, has made its place in all the developed and the developing countries of the world. A few definitions of agroforestry are as under: •"A sustainable management system for land that increases overall production, combines agricultural crops, tree crops and forest plants and/or animals simultaneously/or sequentially and applies management practices that are compatible with cultural patterns of local population". •"Agroforestry is a collective name for land-use systems and technologies in which woody perennials including trees, shrubs, bamboos etc. are deliberately combined on the same land- management unit with herbaceous crops or animals either in some form of spatial arrangement or temporal sequence." •"Agroforestry is a land-use that involves deliberate retention, introduction, or mixture of trees or other woody perennials in crop/animal production field to benefit from the resultant ecological and economical interactions". •"Agroforestry is a dynamic, ecologically based, natural resource management practice that, through the integration of trees on farms and in the agricultural landscape, diversifies and sustains production for increased social, economic and environmental benefits". In agroforestry systems there are both ecological and socio-economic interactions between different components. This implies that •Agroforestry normally involves two or more species of plants (or plants and animals), at least one of which is a woody perennial; •An agroforestry system always has two or more outputs; •The cycle of an agroforestry system is always more than one year; and even the simplest agroforestry system is structurally, functionally, and socio-economically more complex than a mono-cropping system.

It needs to be clearly understood that specifying the existence of spatial-temporal arrangements among components does not help in defining agroforestry, but its value lies in classifying agroforestry examples. Multiple cropping as opposed to multiple uses is a necessary condition to agroforestry. Production diversification is not exclusive to agroforestry and does not help in defining agroforestry. The sole existence of economical interactions among the components is not a sufficient condition to define agroforestry; biological interactions must be present. Similarly the term significant interactions among the components can not be used objectively in defining agroforestry, and its use should be avoided. The presence of animal is not essential to agroforestry. Agroforestry implies management of at least one plant species for forage, an annual or perennial crop production. Once appropriate time limits are imposed on the system, time sequences involving at least two plant species with at least one woody perennial must be considered agroforestry. On the basis of this analysis, the final definition of agroforestry could be: "Agroforestry is a form of multiple cropping which satisfies three basic conditions (i) there exists at least two plant species that interact biologically, (ii) at least one of the plant species is a woody perennial and (iii) at least one of the plant species is managed for forage, annual or perennial crop production."

Fig. : Mustard with Cassia fistula It shows that agroforestry is a new name for a set of old practices. In simple terms agroforestry is "an efficient land-use system where trees or shrubs are grown with arable crops, seeking positive interactions in enhancing productivity on the sustainable basis". Agroforestry combines agriculture and forestry technologies to create more integrated, diverse, productive, profitable, healthy and sustainable land-use systems. The most important agroforestry practices are windbreaks, riparian forest buffers, alley cropping, silvopasture and . Agroforestry is a "social forestry" - its purpose is sustainable development. Practices are focused on meeting the economic, environmental and social needs of people on their private lands. At the farm level, agroforestry is a set of practices that provide strong economic and conservation incentives for landowner adoption. Incorporated into watersheds and landscapes, agroforestry practices help to attain community/society goals for more diverse, healthy and sustainable land-use systems. Concept of Agroforestry : The concept of agorforestry implies the integration of farming with forestry practices on farm to the benefit of agriculture. This concept perhaps originates from the realization that trees play a vital role in safeguarding the long range interests of agriculture and in making agricultural economy viable. Agroforestry has been considered as viable land use system in the tropical regions. Agroforestry is the new term for the old practice of growing woody perennials with agril. crops or livestock together on the same piece of land. It is a new discipline that integrate both forestry and agriculture to maximize the production of goods and services required by the society at large. A system of land management which avoids the false dichotomy (division) of agriculture and forestry which conserves the ecosystem and at the same time provides the food and wood is called Agroforestry (King 1978).

History of Agroforestry in India In about 700 BC, man changed from a system of hunting and food gathering to food production. Shifting cultivation in India is prehistoric and partly a response to agroecological conditions in the region. as co-existent with agriculture is found to have been prevalent in India from early historic period (500 BC to I st century An) when a certain amount of share in garden crops started to have been enjoyed by the king for providing irrigation. Some stray references occur in different texts of the Vedic literature. The cultivation of date-palm, banana pomegranate, coconut, jujube, aonla, bael, lemon and many varieties of other fruits and requirement of livestock in agriculture and mixed economy of agriculture and cattle-breeding may be traced in proto-history chalcolithic periods of civilization. But in India, the plant husbandry (intentional sowing or planting for production of desirable plants or plant domestication) happened to start under progressively arid climatic zone from about pre-Neolithic period. The role of many common trees such as khejri or sami (Prosopis cineraria), aswattha (Ficus religiosa), palasa (Butea monosperma) and varana (Crataeva roxburghii) in Indian folk-life has been mentioned in ancient literature of Rig Veda, Atharva Veda and other ancient scriptures. Traditional agroforestry systems manifest rural people's knowledge and methods to benefit from complimentary uses of annuals and woody perennials on the sustained basis. It also indicates that farmers have a closer association with trees than any other social group and promoters of forests. In central America it has been a traditional practice for a long time for farmers to plant about two dozen species on a small piece of land configuring them in different planes. In Europe, until middle ages, it was the general custom to clear fell, degraded forests, burn slash, cultivate food crops for varying periods on cleared area and plant trees before or along with, or after sowing agricultural crops. This farming system was widely practised in Finland up to the end of the last century and in a few areas in Germany as late as the 1920s. In certain far- east countries practice, people clear forest for agricultural use- they deliberately spared certain trees which by the end of the rice-growing season provided partial canopy of new foliage to prevent excessive exposure of soil to sun. The farmers and land owners in different parts of the country integrate a variety of woody perennials in their crop and livestock production fields depending upon the agroclimates and local needs. Most of these practices are, however very location specific and information on these are mostly anecdotal. Therefore, their benefits have remained vastly under exploited to other potential sites. It has now been well-recognized that agroforestry can address some of the major land-use problems of rainfed and irrigated farming systems in India, and that a great deal can be accomplished by improving indigenous systems. With the current interests in agroforestry worldwide, attempts are being made in India to introduce agroforestry techniques using indigenous and exotic multipurpose and nitrogen-fixing woody perennials.

Scope of Agroforestry Agroforestry applies to private agricultural and forest lands and communities. These are highly disturbed, human-dominated land-use systems. Targets include highly-erodible, flood- prone, economically marginal and environmentally sensitive lands. The typical situation is agricultural, where trees are added to create desired benefits. Our goal is to restore essential processes needed for ecosystem health and sustainability, rather than to restore natural ecosystems. Agroforestry provides strong incentives for adoption of conservation practices and alternative land uses, and supports a collaborative watershed analysis approach to management of landscapes containing mixed ownerships, vegetation types and land uses. Possible impacts of Agroforestry • Controlling poverty through increased income by higher production of agroforestry products for home consumption and market. • Food security by restoring farm soil fertility for food crops and production of fruits, vegetables, nuts and edible oils. • Empowerment to women farmers and other less-advantaged rural residents whose rights to land are insecure through better negotiations. • Reducing and pressure on forest by providing fuelwood grown on farms. • Increasing buffering capacity of farmers against the effects of global climate change on- farm tree crops and tree cover. • Improving soil health of the farm through ameliorated micro-climate and nutrition level. • Augmenting accessibility to medicinal trees for cure of common and complex diseases.

Features of Agroforestry Agroforestry practices are intentional systematic combinations of trees with crops and/or livestock that involve intensive management of the interactions between the components as an integrated agro ecosystem. These key features are the essence of agroforestry and are what distinguish it from other farming or forestry practices. To be called agroforestry, a land-use practice must satisfy following criteria:

Intentional: Combinations of trees, crops and/or animals are intentionally designed and managed as a whole unit, rather than as individual elements that may occur in close proximity but are controlled separately. • Intensive: Agroforestry practices are intensively managed to maintain their productive and protective functions; these practices often involve annual operations such as cultivation and fertilization. • Interactive: Agroforestry management seeks to actively manipulate the biological and physical interactions between the tree, crop and animal components. The goal is to enhance the production of more than one harvestable component at a time, while also providing conservation benefits such as non-point source water pollution control or wildlife habitat. • Integrated: The tree, crop and/or animal components are structurally and functionally combined into a single, integrated management unit. Integration may be horizontal or vertical, and above or below ground. Such integration utilizes more of the productive capacity of the land and helps balance economic production with resource conservation. Importance of Agroforestry Agroforestry provides a different land use option, compared with traditional arable and forestry systems. It makes use of the complimentarily relationship between trees and crops, so that the available resources can be effectively utilized. It is a practice that supports the environment and has an obvious landscape benefit. Efficient, modern versions of agroforestry have been developed, that are adapted to the constraints imposed by mechanization. The agroforestry plot remains productive for the farmer and generates continuous revenue, which is not feasible in arable land. Agroforestry allows for the diversification of farm activities and makes better use of environmental resources. Owing to increase in population of human and cattle, there is increasing demand of food as well as fodder, particularly in developing countries like India. Each year farmers of the world must now attempt to feed 81 million more people irrespective of weather. It is important to note that there will be 19% decline in cropland per head by the end of this century due to population explosion. Therefore, there is slight scope to increase food production by increasing the area under cultivation. A management system therefore, needs to be devised that is capable of producing food from marginal agricultural land and is also capable of maintaining and improving quality of producing environment. Agroforestry has interesting advantages from three different perspectives. From the agriculture perspective: 1. Diversification of the activities of arable farmers, with the building-up of an inheritance of multi-purpose trees, with continuous revenue from farm. 2. Protection of intercrops and animals by the trees, which have a windbreak effect, providing shelter from the sun, rain, wind, soil erosion and stimulating soil microfauna and microflora. 3. Recycling of some of the leached or drained nutrients by the deep roots of the trees; enrichment of the soil organic matter by tree litter and by the residue of the trees. 4. Possibility of combining the interest of the farmer (for an inheritance of wood) and the farm (for access to cultivated land). Possible increased remuneration for the arable farmer for the trees. 5. An alternative to full reforestation of arable land, permitting the continuation of arable activity on land whose arable potential otherwise is conserved. The tree component can be reversed, the plot stays "clean" (free from scrub) and is easy to destump when the trees are clear felled (the stumps are in lines and few in number). 6. In silvipastoral plots, fodder units can be available at different periods compared to full cropped plots, extending the grazing calender.

From the forestry perspective: 1. Enhancement in the biomass growth of the trees by wide spacing (+80% over 6 years in the majority of the experimental plantations). A large reduction in the maintenance costs of the plantation, due to the presence of the intercrops. 2. Improvement in the quality of wood produced (wide regular rings, suited to the needs of industry), because the trees are not subjected to cycles of competition and thinning. 3. Guaranteed follow-up and tree care due to the arable intercropping activity. In particular, protection against the risk of fire in susceptible areas, with pasture or with intercrops like vine or winter cereals (clear bare ground in summer after stubble ploughing). 4. Agroforestry plantations on arable land allow the development of a quality wood resource that complements, rather then competes with, the products from traditionally exploited forests. It is especially important to produce wood that can substitute for tropical saw logs, which will soon decline in availability and quality. The areas concerned will remain small in terms of their absolute value, but the production of wood from them could become a critical input to the European wood supply network. Tree species that are little used in forestry, but are of high value, could be grown in agroforestry systems: service trees, pear trees, common sorbs, walnut trees, wild cherry trees, maple trees, tulip trees, paulownias, etc… From the environmental perspective: 1. Improvement to the development of natural resources: the total wood and arable production from an agroforestry plot is greater than the separate production obtained by an arable-forest separate cropping pattern on the same area of land. This effect results from the stimulation of complementarity between trees and crops on agroforestry plots. Thus, weeds, which are spontaneously present in young forestry plantations, are replaced by harvested crops or pasture; maintenance is less costly and environmental resources are better used. 2. Better control of cultivated areas of land: by substituting for arable plots, the agroforestry plots contribute to diminishing the cultivated area of land. The intensification of environmental resource use by agroforestry systems is not resulting in more crop products. 3. Creation of original landscapes that are attractive, open and favor recreational activities. Agroforestry plots have a truly innovative landscaping potential, and would improve the public image of farmers to society. This will be particularly the case in very sparsely wooded areas, where plots are developed by planting arable land, and in very heavily wooded areas, where plots are developed by thinning the existing forest. 4. Counteract the greenhouse effect: constitution of an effective system for , by combining the maintenance of the stock of organic material in the soil (the case especially with meadows), and the superimposition of a net fixing wooded layer. 5. Protection of soil and water, in particular in sensitive areas. 6. Improvement of biodiversity, especially by the abundance of "edge effects". This in particular, permits a synergistic improvement integrated protection of crops by their association with trees, chosen to stimulate the hyperparasite (parasites of parasites) population of crops, is a promising way forwards. These favorable characteristics are as coherent with the many objectives of the laws guiding agriculture and forestry, as they are with the directing principles of the Common Agricultural Policy.

Classification of Agro-forestry System Different types of Agroforestry systems exist in different parts of the world. These systems are highly diverse and complex in character and functions. To evaluate understand and seek to improve them requires their classification into different categories. Several criteria can be used in classifying them, but the most common include the system's structure, functions, and socio-economic scale of management and ecological spread. According to Nair (1987), Agro- forestry systems can be classified according to following sets of criteria. 1.Structural Basis:

Consider the composition of the components; specially refer including spatial admixture of the woody component, vertical stratification or the component mix and temporal arrangement of different components. 2. Functional Basis:

This is based on the major function or role of the system; mainly of the woody components (This can be productive or protective). 3. Socio-economic Basis:

Consider the level of inputs or management (low input, high input) or intensity/scale or management and commercial goals. 4. Ecological Basis: Take into account the environmental conditions on the assumption that certain types of systems can be more appropriate for certain ecological conditions. Classification of Structural Basis Agro-forestry System:

In these systems the type of component and their arrangement are important. On the basis of structure, Agroforestry systems can be grouped into two categories I. Nature of components II. Arrangement of components. I. Nature of Components: (A) Agri-silvicultural Systems (B) Silvipastoral Systems (C) Agro Slivipastoral Systems (D) Other Systems II. Arrangement of Components: (A) Spatial Arrangement (B) Temporal Arrangement Classification of Agroforestry Based on Arrangement of Components The arrangement of components gives first priority to the plants. Even in Agroforestry systems involving animals, their management according to a definite plan. 1) Spatial Arrangement: Spatial arrangements of plants in an Agroforestry mixture may result in dense mixed stands ( as in home gardens) or in space mixed stands (as in most systems of trees in pastures). The species (or species mixtures) may be laid out in zones or strips of varying widths. A common example of the zonal pattern is hedgerow intercropping (alley cropping). 2) Temporal Arrangement: Temporal arrangements of plants in Agroforestry may also take various forms. An extreme example is the conventional shifting cultivation cycles involving 2-4 years of cropping and more than 15 years of fallow cycle, when a selected woody species or mixtures of species may be planted. Similarly, some silvopastoral systems may involve grass leys in rotation, with some species of grass remaining on the land for several years. These temporal arrangements of components in Agroforestry are termed coincident, concomitant, overlapping (relay cropping), separate and interpolated. Classification of Agro-forestry System on Functional Basis This classification based on the major function or role of the system. Mainly on the woody component, this can be as productive or protective. a) Productive Functions: i) Supply of Food: The tree species in agroforestry mainly fruits and nuts can supply food to the increasing population. The fruit trees like Mango, Ber, Jackfruit, Jamun, Tamrind, Wood apple, Bael, Caronda can supply the food. ii) Supply of Fodder: For 41 cores cattle to feed sufficient quantity of fodder is required which is supplemented by trees like Subabhul, Vilayti chinch, Hadga, Shevari, Neem etc. iii) Supply of Fuel Wood: The species like Subabhul, Khair, Sissoo, Casurina etc. can supply the fuel wood required for cooking. Thus diverting the cow dung to agriculture. iv) Supply of Timber: The agro-forestry can produce the timber wood in addition to the food grains by planting the trees like Teak wood, Eucalyptus, Silver oak, Sal, Arjun, Mohagoni. The timber wood is required for doors, windows, railway sleeper, furniture, poles and post for construction of bridges and for centring. v) Other Products: A number of minor forest products like flower medicinal plants, fibre, floss.gum, lac, tannin, resin etc. are obtained and thus, flourish the small cottage industry there by increasing employment. b) Protective Function: Protecting and mentioning production systems

1) Wind break 2) Shelter belt 3) Soil conservation 4) Moisture Conservation 5) Soil improvement 6) Shade (from crop animal and man) Classification of Agro-forestry System on Socio-economic Basis Based on such socioeconomic criteria as scale of production and level of technology input and management, agroforestry systems have been grouped into three categories a) Commercial, b) Intermediate and c) Subsistence Systems

Commercial Agro-Forestry Systems: The term commercial is used whenever the sale of the production of the output (usually a single commodity) is the major aim of the system the scale of operations is often moderate to large and land ownership may be government, corporate or private. Commercial production of shade-tolerating plantation crops such as coffee, tea and cocoa under over storey shade trees; rotational timber/food crops systems in which a short phase of food-crop production is used as a silvicultural method to ensure establishment of the timber species (various forms of taungya); commercial grazing and ranching under large-scale timber and pulp plantations etc. Intermediate Agro-Forestry Systems: Intermediate Agro-Forestry systems are those between commercial and subsistence scales of production and management, production of perennial cash crops and subsistence crops undertaken on medium to small size farms wherein the cash crops cater for the cash needs and the food crops meet the family's food needs. Subsistence Agro-Forestry System: Subsistence Agro-Forestry systems are those wherein the use of land is directed towards satisfying basic needs and is managed mostly by the owner/occupant and his family. Cash crops, including sale of surplus production of commodities, and all forms of traditional shifting cultivation are the most widespread examples Ecological Classification of Agro-forestry Systems: Based in the major agro ecological zones, agroforestry systems are grouped into the following categories: 1) Humid/sub humid lowlands, 2) Semi-arid/arid lands, 3) Highlands Agroforestry Systems in Humid/Sub Humid Lowlands: This is characterized by hot humid climate for all or most of the year and an evergreen or semi - evergreen vegetation. The lowland humid and sub humid tropics (commonly referred to as the humid tropics) are by far the most important ecological region in terms of the total human population it supports, extent of area and diversity of agro forestry and other land-use systems. Because of climatic conditions that favour rapid growth of a large number of plant species, various types of agroforestry plant associations can be found in areas with a high human population, e.g. various forms of home gardens, plantation crops with combination and multilayer tree gardens. In areas of low population density, trees on rangelands and pastures, other silvopastoral systems, improved fallow in shifting cultivation and multipurpose tree wood lots etc. are the major agro forestry systems. Semi-Arid and Arid Lands: This region is characterised by rainfalls confined to 9-12 hours per day in July-Sept 2 to 4.5 wet months, vapour pressure deficit ranging from 9 mb in Jan to 30 mb in April-May, solar radiation incidence (400-500 cal/cm2/day), high wind velocity (20 km/hour), high potential evapotranspiration (6 mm/day) and high mean Aridity index (70-74.8%). Agroforestry Systems in Tropical Highlands: This area is characterised by uneven topography, varying levels of rainfall, degraded and shallow lands at high altitude to deep rich soils in valleys and great climatic variations. The Himalayan region is an excellent example of this type of area. Land use problems in the highlands are similar to those in humid or dry lowlands, depending on climate, with the addition that sloping lands and step terrier make soil erosion a major concern.

Benefits of agroforestry I. Multiple needs : - It yields extended range of products viz., food, fodder, fuel, fibre fertilizers fruits fence etc. Presence of trees gives extended range of management options and trees can be harvested as per farmers choice and market demands. II. Soil and water conservation : � Trees stabilize the soil conservation structures and make productive use of land � Act as vegetative barrier and check run off. � Reduce rain drop impact and control soil loss. � Trees utilize off season precipitation. � Serves as a shelter belt and reduce wind velocity. III. Nutrient recycling : � Trees recycle the nutrients both from atmosphere and lower soil layers. � In situ green leaf manuring through leaf drop. � Green leaf mulching by applying lopped foliage. � Trees check the increase in soil temperature specially in summer months there by protect the soil microflora and fauna. IV. Employment Generation � Off season family labour utilization � Assured income for the labourers round the year � Prevention of labour migration V Drought Proofing • It imparts stability besides resulting in risk reduction even one component fails the other would give a harvest. • Results in improved and stable income. VI Bio-aesthetic • It can be devised for landscaping and beautification of country side which provide recreation and increase aesthetic value. • Conserving the ecosystem.

Fig. Benefits of agroforestry Briefly the benefits of agroforestry are: ● Provision of fruits and other food, e.g. honey ● Provision of poles and timber ● Improvement of soil fertility ● Provision of material for traditional medicine ● Provision of fodder ● Provision of fuelwood ● Control of soil erosion ● Stabilization of stream and river banks.

The Future of Agroforestry— The USDA Agroforestry Strategic Framework provides new direction on how U.S. Department of Agriculture (USDA) agencies, partners, and landowners together can significantly expand agroforestry to balance agricultural production with natural resource conservation. The agroforestry community is provided an opportunity to positively influence the long-term health and sustainability of all lands for future generations. The key concept in agroforestry is working trees – putting the right tree, in the right place, for the right purpose.

Criteria of selection of trees in agroforestry: The tree component A good agroforestry species should have at least some of the following characteristics: 1. Fast growth, e.g. Senna siamea (Makechi N) 2. A light, open crown, e.g. Faidherbia albida (Musangu N) to reduce shade if grown with crops 3. Ability to coppice or respond to pollarding, e.g. Piliostigma thonningi (Msekese N) 4. Provide products like poles, food, fodder and medicine, e.g. Parinari curatellifolia (Mpundu N) 5. Nitrogen fixation, e.g. Sesbania sesban (Jelejele N) 6. Deep rooted, e.g. Pterocarpus angolensis (Mulombe N) to reduce competition if grown with crops 7. Should not harbour pests and diseases 8. Be easy to propagate and manage, e.g. Tephrosia vogelii (Buwa N). In short, the tree should be compatible with crops or livestock. A farmer is likely to appreciate a tree that gives him or her higher yields. The farmer.s perceived value of the direct benefits, e.g. poles and timber, and the indirect benefits, e.g. erosion control and nitrogen fixation, should be high. Which product or service is seen as being most important may vary from one area to another and from one farmer to another according to his needs. In fact, the values attached to various products or services may often vary even within the family, e.g. the wife.s preferences may sometimes be quite different from those of her husband. Thus it is desirable to involve both wife and husband in discussions on tree species. Where land holdings are small, very competitive trees (e.g. Eucalyptus spp., Acacia mearnsii) may not be accepted by the farmers even if they are fast growing and have valuable production. Trees with a deep root system are usually less competitive with crops than those with many shallow roots. A shallow root system may be desired if the trees are intended to stabilize soil and competition with crops is less important. Examples of trees with shallow roots are Casuarina spp., Cupressus lusitanica and Sesbania sesban, although the latter does not compete much with crops since this species fixes its own nitrogen.

The crop component Some of the more important crop-related factors that determine how the crop will perform with trees are: 1. Light demand 2. Demand for moisture and nutrients (or the .aggressiveness. of the crop) 3. Potential for bird damage 4. The distribution of roots in the soil profile. 5. The potential for wind damage. Characteristics of some important crops in relation to agroforestry Crop Demand Demand Risk of Root Risk for for light for bird distribution/ wind moisture damage nematode risk damage Maize Moderately Demanding No risk Shallow No risk demanding Sorghum Demanding Demanding High risk Shallow Moderately risk Finger Demanding Low High risk Shallow No risk millet Demanding Rice Demanding Very Moderate Shallow No risk Demanding risk Bananas Shade Very No risk Rather deep, High risk tolerant Demanding Nematode risk Sweet Demanding Low No risk Rather Shallow, No risk potatoes Demanding Nematode risk Irish Shade Demanding No risk Shallow No risk potatoes tolerant Tobacco Demanding Low No risk Shallow No risk Demanding Sugar cane Very Very No risk Shallow No risk demanding demanding Sunflower Moderately Low Some risk Shallow Some risk demanding Demanding Groundnuts Demanding Moderately No risk Deep No risk demanding

Different agroforestry systems prevalent in the countr: Several agroforestry systeme in different ACZs of India are given below.

Chapter 9 Shifting cultivation & Taungya

Introduction Shifting cultivation, also called ‗‗swidden‘‘ agriculture or ‗‗slashand- burn‘‘ agriculture, is one of the oldest forms of farming and consists of cropping on cleared plots of land, alternated with lengthy fallow periods. These systems are the dominant form of agriculture in tropical humid and subhumid upland regions and are typically associated with tropical rain forests. Shifting cultivation is practiced on about 22% of all agricultural land in the tropics and is the primary source of food and income for some 40 million people. Shifting cultivation, a primitive system of agriculture, the first step in transition from food gathering and hunting to food production is nearly 9000 years old agricultural practice and believed to have started during Neolithic period. It is prevalent not only in India but in other countries of Asia, Africa, South America and Australia. This is extensively practised by the tribals throughout the tropical and subtropical region. In India, about 5.0 million tribal families are practising this system on 4.37 million hectare of land covering 11 states.

SHIFTING CULTIVATION IN DIFFERENT STATES OF INDIA

Jhum cycle The soils are poor, infertile with low water holding capacity situated on sloppy land. This system involves the cultivation of crops on a patch of cleaned forest area vicinity to their settlement. Trees and bushes are cut during November-January, allowed to dry and burnt by fire. Before the onset of monsoon seeds are sown or dibbled. Different crops grown are millets, cereals, pulses and oilseeds mixed or rarely separated. In one patch, this process continues for 2-3 years till the fertility runs down. Then, the patch is abandoned and a new site is selected for the purpose. The abandoned patch regenerates, become fertile but the original forest flora, fauna and ecology are never restored. The tribals came back to this patch after 20-30 years. This period is called a jhum cycle. Due to demographic pressure this period has come down to 3-4 years in Orissa. The fertility status never build up during the short period.

Fig. Jhum cycle.

With reduction in jhum cycle from 20–30 years to 2–3 years, the land under shifting cultivation looses its nutrients and the top soil. With reduction in crop yield, the families start moving to other virgin areas. Now a stage has come that it has already affected 2.7 million ha of land, and each year 0.45 ha of land fall under shifting cultivation, in northeast India. Frequent shifting from one land to the other has affected the ecology of these regions. The area under natural forest has declined; the fragmentation of habitat, local disappearance of native species and invasion by exotic weeds and other plants are some of the other ecological consequences of shifting agricul-ture. The area having jhum cycle of 5 and 10 years is more vulnerable to weed invasion compared to jhum cycle of 15 years. The area with fifteen-year jhum cycle has more soil nutrients, larger number of species, and higher agronomic yield compared to jhum cycle of 10 and 5 years.

Field practices in shifting cultivation Site inspection: During the months of November and December, landowners visit their potential sites for cultivation in the following year. If they decide to cultivate (or rent out) the land, they will contact other farmers willing to form a group. The members of the group accompany the owner for a site inspection. The primary reason for this advance inspection is to make sure that the tsheri land is matured for cultivation. If the group finds that the proposed land is ready, they delineate the boundary in order to enable clearing and cutting in the absence of the landowner. The criteria used by farmers in Pema Gatshel to determine the maturity of tsheri land are described below.  The crown cover of the standing vegetation is dense and sunlight does not penetrate to the ground, so that grasses and shrub undergrowth are almost absent.  The colour of the topsoil is very dark (almost black) and the ground feels spongy when walked on, confirming sufficient accumulation of humus.  Height and diameter of the predominant trees are sufficient to release enough nutrients during the next fallow period. (The main trunk of the trees, generally saplings 3 to 12 years old, is not burnt but left to decompose to recycle nutrients).

Photo: Maize cultivation on tsheri land, which has been cleared after a fallow period of about two years Cutting and drying of vegetation: After the site selection, the standing vegetation is cut and left to dry for at least two months before burning and sowing. At higher altitudes (1 500 m) the cutting starts during December because it takes a longer time to dry. In the lower altitudes tsheri is cleared during January and February. The cutting will involve tree felling and trimming of branches. In the majority of cases the site is clear-felled. Some farmers retain economically valuable timber trees. Burning and clearing: Burning is one of the critical elements of cultivation. Farmers pay maximum attention while burning the dried vegetation to avoid fire hazards outside their land and to achieve maximum burning. If the fire spreads more than 137 m (150 yards) inside the forestry boundary, the owner is punishable by law. If the fire damages life and property of the villagers, the owner has to pay heavy penalties, including imprisonment for up to three years, depending upon the seriousness of the damage done. Villagers are therefore very careful while burning. They have developed very scientific and organized systems for burning. Scientific fire lines are established around the tsheri before burning. According to farmers, the fire hazard has been reduced in recent years owing to increased precautionary measures. It is believed that if burning is successful, grass growth will be minimal and production will be higher. The unburnt wood is left in the field for slow decay. Fuelwood is collected for home consumption. Sowing, weeding and protection of the crop: Sowing or seed broadcasting is done immediately after burning with no soil preparation. Farmers believe that the heat of the ash helps fast germination. The seeds are sown in stick holes or broadcast over ash. Weeding is carried out only once with machetes and sickles. The seeds are protected from birds until they germinate and seedlings are established. In the case of maize, the farmers watch for one month from morning until evening. The germinating crop has to be protected from wild animals such as monkeys, porcupines, parrots and wild boars. Protection against birds and wild animals is one of the major labour inputs in cultivation. Farmers reported that the damage by wild animals is increasing every year. Effects of Shifting Cultivation i) It is an easy method of deforestation. ii) The wild animals loss their shelter. iii) Springs below the hills dry up. iv) Causes heavy flood in the rivers below. v) Increases water / moisture scarcity for plants, animals and human being. vi) Siltation to the tanks, nallas, river and reservoirs. vii) Ecology is disturbed and distored which never restored. viii) Soil erosion : The problem of soil erosion due to shifting cultivation is very serious. The intensity of erosion depends on slope, soil characteristics, crop coverage, depth of soil and rainfall pattern etc. Loss of soil and nutrients due to erosion is also found. Control Measures The system of shifting cultivation can not be avoided completely but should be discouraged. The alternate substitute for the system should be advocated among the tribals. Approach for the process can be done in following ways. 1.Physical, 2. Agronomic, 3. Socio Economic Physical : It deals with the development of infrastructure facilities keeping the climatic and physiographic situation in view. The objective is to control soil erosion, development of a fertile land with many fold uses and conservation of rain water. It includes * Contour bonding (30% slope) * Graded bonding 30-60% slope * Bench terracing (60-100% slope) * Contour ditches (71500 mm annual rainfall) * Grassed water ways-spill ways * Water harvesting structures, ponds. Agronomic : Management of different crops to get good harvest and fulfil the need of tribals are aimed at. The various steps followed are : - Contour plowing : Plowing across the slope - Selection of crop variety - Integrated nutrient management including more organics and Bio-fertilizers. - Mixed farming : poultry, dairy, piggery, fishery, goatery, apiary, mushroom and cultivation of medicinal plants. Socio-economic The rational behind the persistency of this system in the part lay in it's compatibility with physio-social environment of sparse population, community land tenure system, undulation, poverty, meagre resources, illiteracy etc. with the tribal people. It may not be possible to stop shifting cultivation overnight but the tribals can be persuaded and educated to adopt modern technologies for their resources on a sustained basis.

Taungya: Taungya is Burmas ward meaning hill cultivation, it was introduced into-India by Dr. Brandis in 1890 and the first Taungya plantation was raised in 1896 in north Bengal. It is practiced in Kerala, West Bangal, U.P., and to lesser extent in Tamil Nadu, A. P. Orissa and the north eastern hill regions. In southern India the system is called KUMARI, it is practiced in a areas with an assured annual rainfall of over 1200-1500mm. This is a modified term of shifting cultivation in which labour is permitted to raise crop in an area but only side by side with the forest species planted by them. The practices consist of land preparation, tree planting, growing agricultural crop for 1 to 3 years until shade becomes the dense and then moving on to repeat the cycle in a different area. Traditional Taungya consist of land preparation for tree plantation, growing agricultural crops for 1 to 3 years after the tree plantation and moving on to another area to repeat the cycle. There are three types of Taungya . a) Departmental Taungya: Under this, agricultural crops and plantation are raised by the forest department. By employing daily paid labours the main aim of raising agril. crops along with the plantation is to keep along with the land free of unwanted vegetation. b) Leased Taungya: The forest land is given on lease to the person who affects the highest money for raising Agril. crop for a specialized number of years and ensure care of tree plantation. c) Village Taungya: This is the most successful of all the three Taungya systems. Under this the people who have settled down in a village inside the forest for this purpose raise crops. Usually each family has about 0.8 to1.7 ha of land has raise trees and cultivate crops for 3 to 5 years. Advantages of Taungya System: i) Artificially regeneration of the forest is done at cheaper rate ii) Problem of unemployment is solved to some extent iii) Better utilization of land iv) Remunerative to forest department Disadvantages of Taungya System: i) Creates certain legal problems ii) Exploitation of hum in labour iii) Danger of epidemic iv) Provision v) Loss and soil fertility

Chapter 10 Alley cropping:

Introduction Alley cropping is an agroforestry practice intended to place trees within agricultural cropland systems. The purpose is to enhance or add income diversity (both long and short range), reduce wind and water erosion, improve crop production, improve utilization of nutrients, improve wildlife habitat or aesthetics, and/or convert cropland to forest. The practice is especially attractive to landowners wishing to add economic stability to their farming system while protecting soil from erosion, water from contamination, and improving wildlife habitat.

Definition Alley cropping is broadly defined as the planting of rows of trees and/or shrubs (single or multiple) at wide spacing, creating alleyways within which agricultural crops or horticultural crops are produced. The trees may include valuable hardwood veneer or lumber species, nut or other specialty crop trees/shrubs, or desirable softwood species for wood fiber production.

Fig. In an alley cropping practice an agricultural crop is grown simultaneously with a long term tree crop to provide annual income while the tree crop matures. Benefits • Improved economic stability • Increased cash flow • Improved plant/animal diversity • Sustainable agricultural systems • Improved aesthetics

When designing an alley cropping practice, considerable thought must be given to which trees and crops will be grown together and at what spacing. Because of the interaction between the tree and crop components and the goal of optimizing economic gain, a mix of trees and companion crops should be created that provides the highest return on the landowner‘s investment. For example, a typical tree/row crop alley cropping practice might begin with walnut/soybeans and eventually convert to walnut/cool-season grass. The trees might be planted 15 feet apart within the rows with 70 feet between rows to accomodate crops. Of course, there are many different tree and crop combinations, as well as many different spacing possibilities.

Factors to Consider • Maintenance programs (timing & methods) • Size of farming equipment (affects spacing requirements) • Possibility of increasing undesirable wildlife populations • Direction of sun • Light requirements of companion crops • Chemical interactions between trees and companion crops

Desirable Characteristics of Trees The desirable characteristics of trees will vary depending on the goals, objectives and priorities of the user. A first consideration is to make sure the soil (site) is suitable for the tree species chosen. Also, ideally, the tree species should have high commercial or environmental value and the physical characteristics of the trees must create suitable microenvironments for the companion agricultural crops. Following are some of the more desirable characteristics for trees being considered. While not all of these characteristics will be present in all trees, they should be considered. Generally, trees should: • Produce a high-value product or multiple high-value products such as wood, fruit, nuts, and chemicals, and have an acceptable local market • Be relatively fast growing (medium growth rate on high value trees might be acceptable) • Be adapted to site and soil conditions

Fig. Desirable Characteristics of Trees

• Produce appropriate shade for the companion crop (i.e., grain and some forage crops have low shade tolerance) • Have minimal roots at the soil surface to minimize competition with crops in the alleyway. • Have foliage with minimal acid-generating potential as most companion crops prefer a pH neutral soil • Not produce growth-inhibitory chemicals (allelochemicals) that would prevent some crops from growing near them. However, some species, such as black walnut, have such high value for both nuts and wood that it may still be selected. By understanding which crops are effected by the specific allelochemical, compatible companion crops can be chosen. • Have a growing season that complements the companion crop‘s growth period • Produce wildlife benefits. Tree Arrangement Alley cropping is unique compared to traditional agriculture or traditional forestry because, through the interaction of trees and crops, the goal is to maximize the economic gain based on the combination of the two. Alley cropping practices are highly diverse and range from simple to complex. When deciding the best tree arrangement, consider: • The growth characteristics of potential tree species • Whether single or multiple rows should be planted • Whether single or mixed species should be used • What the spacing should be both within the tree rows and between the rows • Light requirements of companion crops Having knowledge of the growth characteristics of trees and the companion crops will help determine whether trees should be planted in single or multiple rows, and whether single or mixed species should be used. Some trees have a stronger response to light than others. For example, pecan planted in single rows under open conditions requires intensive management to produce a quality saw log. The tree tends to grow out instead of up, responding to light on all sides and requires extensive pruning. This is fine if the end product is a pecan orchard but not for pecan logs. If veneer or sawlogs are a desired product, extensive pruning will be needed. However, when grown in the center of a triple row configuration with different species on either side which are not as responsive to light (e.g. hazelnut), pecan can be ―trained‖ to produce a less-branched, high-value log. Growers also need to understand growth characteristics of juvenile trees. Growth rates of different species may conflict, especially when species are mixed in the same tree row. If not properly designed, one or more species may dominate the site and have a negative effect in mixed species plantings. Spacing Spacing between rows and between individual trees is critical in designing an alley cropping practice. • Between-row spacing varies depending upon a variety of management decisions. For example: Trees planted for wood fiber production will require less between-row spacing than if nut production is emphasized. • Within row spacing varies with the intent of the alley cropping program. For example: 1) for erosion control, plant trees on close spacing to provide an immediate effect; 2) for nut tree production, plant on a wider spacing to allow sufficient space for trees to fully develop their crowns for nut development. • To grow shade intolerant crops in alleys for more than a few years (five to10) requires wide alleys to allow for expanding tree crowns and for moisture competition from the trees. • Alley widths should be planned in conjunction with the size of the equipment being used to maximize the efficiency of the management, maintenance and harvesting operation. Maintenance Considerations • Fence, or use other means, to protect tree seedlings from grazing and/or browsing • Control weeds during initial years until trees reach adequate size to survive on their own • Apply fertilizer according to soil tests (usually not recommended for the crop) • Apply pesticides as needed Chapter 11 Wind breaks and shelter belts, home gardens

Windbreaks are plantings of single or multiple rows of trees, shrubs or grass that protect crops, livestock, wildlife or people from wind‘s harmful consequences. Historically, Windbreaks were planted for a single purpose, such as protecting homes from cold winds or soil from erosive winds. Today, Windbreaks are being used to address numerous other problems and provide a variety of other benefits. When properly designed, located and managed Windbreaks can produce one or more environmental and economic benefits. It is important to remember that not all potential benefits can be realized from every Windbreak. In fact, some Windbreak purposes will require conflicting design characteristics Trees and shrubs can be planted along boundaries of fields and structures for demarcation purposes. Traditionally, field boundaries were planted with trees for permanent demarcation. Trees can also be planted along roadsides for beautification and to provide shade for pedestrians. Windbreaks are lines of trees or shrubs planted for the purpose of protecting crop fields, institutions, houses, etc., from wind damage. In Eastern Province planting around field boundaries and on soil-conservation structures should, in most cases, offer sufficient wind protection since the area does not experience strong winds.

Benefits of windbreaks:

Improve income — Whether a grain, vegetable, hay, vine or orchard crop, net yields can be increased by 10 to 20 percent in fields with Windbreaks. Livestock experience improved weight gains resulting in lower feed costs. Heating and cooling costs for the farmstead can also be reduced. In addition, income producing plants such as fruit trees, nut trees and woody florals can be incorporated into a windbreak without reducing the beneficial functions.. Provide protection — Windbreaks protect crops, facilities, livestock, people, soil and water from the damaging effects of wind and wind blown material. Windbreaks can create a more comfortable working and living environment by providing protection from cold winter winds, hot summer winds and blowing and drifting snow. Store carbon — A dense tree and shrub planting, including Windbreaks, will create net gains in carbon storage or sequestration. As the plantings mature this helps to rebalance the global carbon cycle. Enhance aesthetics — Windbreaks generally add desirable plant variety that enhances the appearance of the landscape. Windbreaks also can screen undesirable views and provide opportunities for protecting and viewing wildlife Criteria for selection of species Trees that would be suitable for windbreaks should be: ● Easy to establish ● Easy to manage ● Not harbour pests and diseases ● Deep rooted ● Resistant to wind ● Provide minimum competition for light, water and nutrients to adjacent crops ● Not spread on their own. Recommended species Suitable species for boundary planting: ● Azadirachta indica ● Casuarina spp. ● Eucalyptus camaldulensis ● Eucalyptus tereticornis ● Tamarindus indica

Establishment The main method of establishing windbreaks is by seedlings. Planting a single line of trees is sufficient to mark a boundary and to serve as a windbreak. A windbreak should be established at a right angle to the prevailing wind direction. The spacing between treesis normally 2 m, but this may vary with species.

The efficacy of a windbreak can be improved by planting tall trees in the first line and shorter trees in a parallel line. If the boundary separates two fields, the first line of trees should be placed one or two metres inside the boundary. If both farmers are interested, each can plant a line of trees inside their boundary.

Considerations for windbreaks: Vegetation — Final selection of the species of trees and shrubs to plant will vary at each facility and farm site and should be based on: soil type, natural drainage, common wind conditions, annual precipitation, natural range of each woody species and site needs. Density — The more solid or dense a Windbreak, the greater the wind speed reduction. However, less dense plantings provide protection to a greater distance. Density can be managed by the plant species chosen, the spacing within and between rows and the number of rows. Orientation — Windbreaks are most effective when oriented at right angles to troublesome winds. To allow for changes in wind direction, Windbreaks are often planted in multiple directions — in an L-shape or an arc. Avoid placement that may interfere with overhead lines, buried cable and road visibility. Height and Length — The height determines how far downwind the protection will reach. For adequate protection the Windbreak must be taller than what is being protected. The length helps determine the total area that will be protected. Pest Control — Because every tree counts in a Windbreak, it is important to regularly monitor for the presence of insects and diseases. Early detection and treatment is the most effective way to control pests. Wildlife and livestock can also cause damage that is best prevented with fences or other deterrents. Management — Proper care of the Windbreak is critical to its long-term functioning. Windbreaks need regular maintenance and attention from the day they are planted. Practices such as weed control, protection from livestock and wildlife damage, corrective pruning, replanting, insect and disease control, and supplemental watering may be needed on a continuing or periodic basis.

Fig. Windbreaks can increase net yields of many crops by 10 to 20 percent.

Management Protect young trees against livestock and fires. Termite control is necessary for trees such as eucalyptus which are susceptible to termite attack. Mature trees can be selectively pruned or pollarded to reduce the shading effect on the adjacent agricultural crops Shelterbelts Natural shelterbelts are strips of trees which are left when establishing new fields. The main functions of natural shelterbelts are to protect fields from runoff and wind damage. They also provide tree products like fuelwood, timber, fruits and medicine. In Eastern Province natural shelterbelts are mainly found in settlement schemes.

Establishment Natural shelterbelts should be aligned across the slope for them to be effective in soil conservation. The width of a shelterbelt can range from 30 to 50 m and the length will depend on the area of the piece of land under cultivation. Spacing between shelterbelts can be 50 m or more depending on conditions.

Management Natural shelterbelts require sound silvicultural management practices to sustain their productivity. Fires have generally been one of the biggest problems in management of forests. Early burning of shelterbelts from May to June is recommended. Controlled grazing should be practised in order to avoid overgrazing. Trees can be pollarded or coppiced. This will ensure sustainable use of forest products. Natural regeneration should be well protected. The following species tolerate pollarding: Albizia spp., Bauhinia spp., Ficus spp., Syzygium spp. and Terminalia spp.

Shelter Belts and Wind Breaks : Need for shelter belts and wind breaks : The arid regions of the world are characterized by temperature extreme, low and erratic rainfall, strong hot and cold winds, high evaporation rates and reduced soil productivity. In many areas there is a general shortage of adequate fuel wood fodder and shelter which can contribute to poor socio-economic conditions. The problems in arid areas often seem so vast diverse and challenging that no amount of modern knowledge can make meaningful changes in the landscape. However changes are being made in making the deserts more productive and as desirable places to live. These changes are often made possible by planting of wind breaks shelter belts and block from vagaries of nature. In addition in developing countries these plantings are the critical source of fuel for domestic consumption. There is a little doubt that wind break play a very important role in combating desertification controlling wind erosion, crop damage and improving the yield and quality of crops through the amelioration of the microclimate. Functional roles of shelter belts : 1) Protecting soils, crops and livestock 2) Conserving soil moisture and irrigation efficiency 3) increasing farm management options flexibility and diversification of enterprise 4) Improving working conditions and general efficiency of wind 5) Conserving fuel in green house, farm, domestic buildings and transport system 6) Providing fuel from wood. 7) Providing timber for farm use or sale. 8) Conserving wild life and other ecological values 9) Enhancing landscape values 10) Improving capital values. Design Criteria : The term wind break refers to one or two rows of protective planting of trees whereas a shelter belt is a more extensive and a long barrier. Wind breaks are planted perpendicular to the direction of wind in a given locality. Generally in our country the wind breaks are planted in North South direction to meet the wind forces from south west and north east. Properly designed shelter belts show the effect over a distance of 40 times the height of the wind break. There are two distinct zones on the leeward side of the wind breaks a triangular quiet zone starting from top of the wind breaks and extending near to the ground level to a distance of 8h where the turbulence velocity fluctuations of wind are reduced and below the values of approach flow. 2) Above and down wind of the quiet zone is a wake where the turbulent fluctuations are greater than those in approach flow. The degree of protection offered by a wind break depends upon the orientation, height, density, species composition and spacing of the wind break. 1. Orientation : Wind breaks should be oriented at right angles to the prevailing or problems winds because the protected zone has maximum extension in the down wind direction. 2. Height : The protected zone associated with wind break is directly proportional to the height of wind break. Hence the height should be from the top of the crop canopy and should be atleast two to three times the height of the crop. 3. Density : Moderately dense wind breaks significantly reduce the wind velocities (50 – 60%) wind breaks with lower densities are generally in effective for most crop protection purpose. The moderately dense wind breaks do not cause as much down wind turbulence as dense wind breaks hence they are more effective. 4. Species Composition : The most desirable plants for a variety of field wind breaks are those that have a density of about 50 – 80% in single row plantings. There spread not exceeding 3 meters and should have a potential height of 5 – 30 meters. Tall narrow crowned species usually provided the greatest benefit for the mount of land taken out of production. 5. Spacing : In general within the row spacing are 1 to 2.5 metes for shrubs 1.5 – 2.5m ST form small trees, 2 – 6 meters MT for medium to tall trees. Normally the spacing between the rows varies from 2 – 6 meters. Characters of tree species for wind breaks : A wide range of plant species have been utilized for wind breaks in the arid areas through out the world. The most important criteria for selection of tree species are 1) Resistant to drought 2) Resistant to frost snow breakage and wind throw 3) Tolerance to temperature extremes 4) Easy to establish long lived 5) Fast growing with tall uniform shape 6) Resistant to pests and disease 7) Should not serve as alternate hosts for fungi and other pests.

Home gardens:

Home gardens or compound farms are production systems of annual subsistence crops and tree crops, sometimes combined with cash crops mainly cultivated around the homestead. They are an important component of traditional farming.Various terms have been used to describe the unit of land on which compound farming is practiced, including compound farm, home gardens, village forest garden, kitchen garden and household garden. Different local names have been given to describe the local home gardens, such as chagga home-gardens in northern Tanzania, quintal or hona familiar in Brazil and also the Indonesian pekurangan, etc. Although a clear definition of home garden is still lacking, the closest description was given by Ninez (1987) as follows: ―a small scale production system supplying plant and animal consumption and utilitarian items either not obtainable, affordable, or readily available through retail markets, field cultivation, hunting, gathering. fishing and wage earning.‖ Home gardens tend to be located close to the dwelling for security, convenience and special care. A prominent characteristic of the home gardens is their cleverly structured system, with each component having a precise place and well-established role. Home gardens are planted with ecologically adapted and complementary plant species, differing in canopy heights and shade tolerances, ranging from herbaceous plants to trees of up to 20 m. They are characterized by low capital input and simple technology. There are different types of home gardens, ranging from more homogenous to complex ones. They are characterized by the following features, which contribute to the biophysical stability and sustainability of the land: high diversity of cultivated plant species; multi stoned vegetation structure; high rate of cycling of organic matter and maintenance of in situ soil fertility. The primary function of the home garden is to produce subsistence items for domestic use and to generate additional income. In home gardens, the tree component is a source of fruits, nuts, vegetables and medicinal products. Home gardens are known for their low but stable yields, continuous or repeated harvest of a variety of produce and low input use. Ecologically, they are stable land- use systems, as the multi-story canopy strata and plant litter can provide effective surface protection against soil erosion. Traditional farmers also use household refuse and ash and sometimes fertilizers to maintain soil productivity, which has created islands of ‗man-made soils‘ with far higher fertility status than the surrounding annually cropped or fallow lands. Despite the progress in descriptive work, many of the biophysical processes and factors contributing to the stability and sustainability of this complex system are still poorly understood.

Trees can be planted around the homestead for shade, beauty, as a windbreak, and for medicine, fruits, timber, poles, fuelwood and fodder. Trees can also improve the microclimate of the area around homes. There are advantages and disadvantages to planting trees in homesteads and around institutions. The major advantage is that it is easy to look after trees and the products (e.g. fruits) are easily accessible to the user. There are, however, several disadvantages too. The trees need protection not only from livestock but also from children and sometimes even adults. Sometimes trees can damage buildings, e.g. by branches or a whole tree falling during rain storms, or roots of trees like Ficus spp. growing into and cracking walls and foundations. Trees can also cause too much shade and dampness and can attract insects and snakes. Criteria for selection of species Trees that would be suitable for planting in homesteads and around institutions should: ● Provide valuable products or services (shade, fruit, beauty, etc.) ● Not shed too much litter ● Be deep rooted ● Be resistant to wind damage.

Recommended species Suitable trees for shade ● Ficus sycomorus ● Mangifera indica ● Senna siamea ● Senna spectabilis ● Tamarindus indica Fruit trees ● Mangifera indica ● Citrus spp. ● Morus nigra ● Prunus americana ● Anacardium occidentale

Ornamental trees ● Delonix regia ● Jacaranda mimosifolia ● Senna siamea ● Senna spectabilis Establishment By cutting, direct seeding and seedlings. Fruit trees must be spaced according to the recommendations for that species. Ensure that the trees are planted at least 5 m away from houses. Trees around homesteads need to be protected against livestock. They can be pollarded, pruned, fertilized and watered to improve the performance and growth. Simple water management techniques such as basins, bunds or half-moon-shaped depressions are useful during dry seasons. However, the best type of management to be used depends largely on the species and the purpose of planting.

Chapter12 Cultivation practices of two important fast growing tree species of the region

1. Eucalyptus (Eucalyptus, tereticornis) Family : Myrtaceae Common Names : Mysore gum, Mysore Hybrid Origin : Native of Australia Phenology : Mysore gum is a tall clean bole, straight tree with white smooth bark and thin evergreen foliage under favourable conditions it attains a height of more than 40 meters and DBH over 65 cm. Bark is shed annually in long stripes or plates. The leaves contain some essential oil which has some medicinal properties. Flowers do not have sepals or petals and appear to consists of only a large no. of stamens. The capsules (fruits) are divided in to 4 or 5 cells which open by valves. Silvicultural characters : It is a versatile tree adopted to a variety of edaphic and climatic conditions. It failed under high rainfall conditions of 2000 mm of Kerala and Assam, does well in well drained soils and can come up in areas with rainfall as little as 500 mm well drained loamy soils are best suited. It is not suitable for steep hill sloes for dry eroded and ravined or water logged areas. It is a strong light demander, without full over head light it becomes lean lanky and crooked. It can tolerate mild frost but not severe drought, can withstand light fires, but young plantation are susceptible to severe fire damage. It has the cardinal advantage that it is not browsed by cattle and also a strong coppicer. Establishment : Natural regeneration – rare, propagated artificially, artificial regeneration. Planting of nursery raised seedling in polythene bag is adopted for large scale plantations planting naked root seedlings or stump planting have met with varying success. Direct sowings are very rare. Seed collection storage sowing and Nursery : Mysore gum starts seeding after 2-3 years. Trees of 5 years old and above seeds profusely. Seeds are very small being 75,000 – 1,00, 000 per Kg. The tree seeds twice a year in autumn (Oct) and summer (May). Seed is collected from dominant felled trees or standing trees of superior phenotype. Air dried seed is stored in air tight containers and retains fair germination capacity for 1 or 2 years. Minute size of the seed calls attention for handling in the nursery. For raising container plants seed is first sown in nursery beds and then pricked out into polythene bags after germination. About 200 gms. of seed per bed of 10 m2 is sufficient. Germination takes place within 5-15 days and each bed yield about 12,000 to 15,000 seedlings.The seedlings are to be pricked out into polythene bag normally 4 to 6 weeks after germination. Seedling grow 1.0 to 1.5 meters tall and fit for planting out in 6-8 months. Plantings are established at spacing of 1.0 x 1.5 to 4.0 x 4.0, meters in pits of 30 cm3 or 60 cm3. Management growth and yield : The crop is clear felled at the end of each rotation and is regenerated by coppice. Under favourable conditions 3 years coppice crops can be taken after which the area is need to be replanted. On an average 90% stumps will coppices. Rotations of 8-14 years may be adopted depending on site quality for . Rotation of more than 12 years is not advisable because the tree develops dark coloured wood. The tree is quite fast growing but growth varies widely with site and management. An average plantation will yield about 5 m3 (3 t/ha/year). The yield form the first coppice is same as the first crop but the 2nd and 3rd coppice crops yield less by 10 – 20%. Utilisation : 1. Fuel wood : Mysore gum gives a good quality firewood and burns slowly. The calorific value of the dry fuel is 4880 K Cal/Kg of wood. It gives good quality weighing 420 Kg/m3 and calorific value is about 7550 K Cal/Kg. 2. Timber : Mysore gum wood is moderally heavy (640 Kg/m3) and hard it is suitable for timber, transmission poles, packing cases, boxes, beams, columns, poles and posts. 3. Pulp wood : Mysore gum wood gives a suitable raw material for paper pulp, news print and grade pulp of good quality. 4. Leaf Oil : Leaves are an important source of essential oil which ―contains cineole‖ oil has medicinal value. 5. Other uses : It is a suitable species for honey production Bark is a suitable raw material which yield oxalic acid (40-45%) by oxidation process. 2. Subabul (Leaucaena, leucocephala) Family : Leguminosae (Horse Tamarind, Khari). Origin : Native of Central America and has been introduced widely in many tropical countries. Phenology : It is a tall tree grown upto 20 meters or a shrub, less than 5 meters in height unarmed and evergreen. It ahs feathery leaves, small white flowers and large bunches of long flat pods each containing 15-30 seeds. Immature pods are light green ad translucent, mature pods are brown shining with waxy cost and open spontaneously when dry. Three types have been mainly recognised 1. Hawaiian types are short bushy trees grow upto 5 meters and mainly grown for fuel wood. 2. the Peru types are medium tall trees, grown upto 15 meters with extensive branching mainly grown for fodder purpose (forage varieties) 3. The Salvador types are tall trees, grow upto 20 meters having large leaves and pods mainly grown for timber etc. Varieties K-8, K-268, Hawaiian giants. Silvicultural Characteristics : Leaucaena, is a light demander, fast growing, can tolerate partial shade, but grows best in full sun. It is frost tender but can withstand drought but prolonged drought may kill the seedlings. It is a good coppicer and pollarder and allows repeated harvests of firewood timber and forage produces plentiful seed in first or second year. It is a species of warm tropics, grow on wide range of soil types but mainly grows on neutral soils. Establishment : 1. Natural regeneration : Leaucaena, reproduces itself fairly through seed coppice. It seeds profusely and the seed gets scattered under the mother tree which establishes well only under full sun and moisture conditions. 2. Artificial regeneration : Leaucaena, can be raised by direct sowing of seed or by planting container raised seedlings. 3. Seed collection and storage : It seeds twice a year July to November and February to May. Pods are collected before they dehisce. The seeds collected after drying the pods are liable to be attacked by stored pests for which the seeds are to be treated before storage. It can be stored for along period of 10 years (Viable seed). The seed requires pre-sowing treatment for quick germination which is being carried by either 1.Mechanical scarification of seed coat 2. Soaking in ordinary top water for 48 hours 3. Soaking in hot water at 80o C for 2 minutes and cooling in cooling in cool tap water for 12 hours. Seed requires inoculation with Rhizobium at 250g/20 kg seed. Germination capacity is 80%. A seed rate of 10-20 kg of seed per ha. is required. A spacing of 3 x 3 meters is recommended. In the nursery the seeds are sown in polythene bags during March – April which germinate in 4 – 6 days and the seedlings attain plantable size by July – August. Management growth and yield : For fire wood the plantations may be harvested in 2 -3 years rotation for timber rotation of 5 – 6 year may be followed for forage the cutting the branches at the frequencies of 1-3 months depending upon the growth rate. Growth in terms of height can exceed 4 m/year initially achieving 20 meters in 5-6 years. Wood yield of 10-20 m3/ha/yr. on average under dryland situation is possible.

Utilization : 1. Fire wood : Leaucaena, wood makes excellent firewood and charcoal and the calorific value of wood is 4200 – 4600 K.Cal/Kg of wood. 2. Timber : The wood is hard strong heavy (about 880 Kg/M3) mostly suitable for carpentry purposes and makes cheap constructional timber and as a poles for fencing. 3. Fodder : Leaves pods and seeds are nutritious digestible and relished by cattle sheep and goats. However a toxic alkaloid mimosine is present in the leaves of some of the varieties at level (2-5%) that can be injurious to health of cattle. It is therefore important to select low mimosine strains (Hawaiian giants) and supplement it with other forages. The mimosine content can be reduced to 50% when leaves are dried at high temperature or by immersing in ferrous sulphate solution. 4. Other uses : Its pulp is mixed with pulp for manufacture of paper, for afforestation of denuded watersheds as wind breaks for farm and agroforestry pods yield a dye used to colour wool cotton, fishing nets, powdered seed make good manure. The plant is said to be a fish poision and worm repellent.