Proceedings: 6th Tall Timbers Fire Ecology Conference 1967

Spatial and Temporal Patterns of Fire in the Tropical World*

ROBERT B. BATCHELDER Department of Geograpby Boston University

F IRE HAS a long history of occurrence in the tropics, and its effects upon the physical and cultural environment have been profound. For various reasons, the frequency of occur­ rence of accidental fires prior to man's use of fire is believed to have been low, and the area subject to devastation limited. It is known that the areal distribution of humid tropical forests during the early Pleistocene was much greater than at present. Combustibility of such forests must have been very low because of the prevailing per­ humid forest microclimate, and fires once ignited would have had difficulty in spreading. It may be assumed therefore, that widespread burning would occur largely in geographic areas supporting grasses and open dry forest where the occurrence of an ecological dry period of sufficient duration and intensity would permit dessi-

• This paper presents part of a more complete investigation into tropical fire sponsored by the U. S. Army Natick Laboratories and reported in: Robert B. Batchelder and Howard F. Hirt, Fire in Tropical Forests and Grasslands, Technical Report 67-41-ES, U. S. Army Natick Laboratories, Natick, Mass. June 1966, 380 pp.

171 Proceedings: 6th Tall Timbers Fire Ecology Conference 1967

ROBERT B. BATCHELDER

cation of available fuels. It must be remembered, however, that Pleistocene grass and brush lands were much less extensive than at present and probably occurred as enclaves in the extensive dense forest. With the advent of man's use of fire, both the frequency of fire and the area subject to burning have increased at an accelerating rate. Various lines of investigation support belief that the control of fire by man may not be more than 12,000 years old, even though man may have guarded and transported fire for thousands of years earlier. (Stewart, 1956). No evidence suggests that man in Africa knew how to make or use fire before the end of the Early Stone Age. In South America, palynological studies of the Llanos Orientales of Colombia and the Rupununi Savanna of Guyana (British Guiana) indicate that the impact of cultural fire in altering natural vegetation was insignificant as late as 3,000 years BC (Wijmstra and van der Hammen, 1965). Over the centuries, fire has been and is still used to drive game, collect honey, ease travel through densely vegetated areas, provide new succulent forage for grazing animals, control pests and disease-bearing insects, and clear land for cultivation. Pyro­ mania and incendiarism also is widespread (Boughey, 1963; Richards, 1964; Phillips, 1965). Use of fire is so deeply ingrained in certain cul­ tures that it has become an essential part of religious beliefs and taboos. For a number of reasons, notably the lack of data and the com­ plexity of the variables involved, the portrayal of the incidence of fire and its areal distribution has not been attempted. Whereas occur­ rence of natural fires is a random phenomena and therefore cannot be mapped, man-set fires follow definite patterns adjusted to climatic seasons, agricultural calendars, and religious beliefs and practices. Because climatic dry seasons and major vegetation formations are known for the tropics, albeit in inadequate detail, it is possible to present cartographically the incidence of fire and its relationship to these characteristics of the physical environment. Maps were thus prepared for the major tropical land areas, and represent a first at­ tempt to portray the spatial and temporal patterns of fire. Interpre­ tation of the maps is enhanced if it is preceded by a brief analysis of the causes of fire and their relative significance.

172 PATTERNS OF FIRE IN THE TROPICAL WORLD

CAUSES OF FIRE

Fires which are intentionally set are far more numerous than fires due to natural causes. This is evident from analysis of the literature even when allowance is made for bias toward cultural use of fire. In those countries that maintain fire records, less than two percent of total fires reported are attributed to natural phenomena. However, caution is required in interpreting records because fires are normally recorded only for forest reserves, forest plantations, and national park and wildlife areas. Even for these areas, the number of natural fires reported are known to include uncontrolled set fires which have invaded the protected lands. The most frequently cited causes of natural fires are lightning strikes, sparks from rock falls, volcanic activity and spontaneous combustion. As would be expected, the number of fires reported set by other than lightning is low. Surprisingly, the number of fires re­ ported set by lightning is also low. Much of the tropics experiences severe thunderstorms in which lightning has been observed striking and igniting vegetation. Combustion, however, is infrequently sus­ tained. A principal reason cited is that violent thunderstorms com­ monly herald onset of a rainy season, and torrential showers accom­ panying such storms quickly extinguish flarpes. Equally significant is the fact that at the time of onset of rains, much of the tropical land­ scape has already experienced fire in preparation for cultivation and grazmg. Man's use of fire takes place under conditions where the inter­ action of cultural and physical variables is so complex as to make impossible a meaningful classification. Therefore, causes of set-fires are arbitrarily grouped under two headings subjectively defined: 1) controlled fires and 2) uncontrolled fires. Controlled fires include fires set by primitive people who exer­ cise certain precautions against fire spread. Control burning also is included, that is, fire used as a tool to modify forest or range so as to enhance commercial exploitation. Fires of swidden (shifting) culti­ vators are in most cases controlled fires in which the forest surround­ ing the cleared site acts as a green firebreak (Fig. 1). Such fires, even when untended, dampen-down quickly at night in humid tropical

173 ROBERT B. BATCHELDER

FIG. 1. A clearing in fairly mature second growth moist semideciduous near Aishalton, Rupununi District, Guyana, South America. Forest acts as a green firebreak. Photo by T. L. Hills. climatic areas, even though they may burn low through the night (Fig. 2). Numerous references to beads and strings of fire on hill slopes are reported by observers on night flights. In dry forest formations, swidden plots frequently are aligned along a forest-savanna boundary. The grassland affords ease of travel while forest soils are more fertile and easily tilled. As clearing pro­ gresses along the vegetation boundary, the forest is degraded to wooded savanna, and the danger of fire escaping to the savannas be­ comes critical (Fig. 3). In 1957, it was estimated that 36 million square kilometers (14 million square miles) -about 25 percent of the earth's land surface-was under swidden cultivation in the trop­ ics; of these, perhaps 3 to 6 million (1.2 to 2.3 million square miles) are burned each year. Control burning as a modern land management practice is increas­ ing in pasture and forest exploitation in parts of the tropics. Principal objectives are to maintain fire-climax rangelands, as for example, the Veld of South Africa and pastures of northern Australia; and to

174 PATTERNS OF FIRE IN THE TROPICAL WORLD

FIG. 2. Brush fire at dusk at end of rainy season (July). Village of Ingoba, Tanzania, 25 miles inland from Dar es Salaam. Photo by 1. J. Stolberg. reduce fire hazard in forests liable to accumulation of highly com­ bustible fuels, as for example in India, Burma, and Australia. Al­ though fires due to control burning are significant especially in South Africa, Australia and India, they are far less significant than un­ controlled fires set by swidden cultivators and graziers. Uncontrolled set fires are the largest single group of causes of fire in tropical forests and grasslands. Included as uncontrolled are fires set by aboriginals, peasants, and ranchers, and are accidentally out of control. Included also are fires set for the sheer pleasure of seeing flames sweep across the countryside, (Fig. 4). More recognition should be given to pyromania and incendiarism as a cause. Accidental fires, set by steam locomotives, careless automobile and truck travel­ ers are widespread but not numerous. Such fires occur along lines of communication, many of which are passable only during the dry season, so that high fire hazard and heavy traffic coincide. The areal significance of uncontrolled set fires is difficult to assess. On the basis of qualitative assessment of the literature and in terms of

175 ROBERT B. BATCHELDER

FIG. 3. Small clearing in gallery forest along bank of Sand River, Northern Rupununi, Guyana. Note ease with which fire could escape to the open savanna. Photo by T. L. Hills.

area burned, fires set in connection with pastoral activity leads, fol­ lowed by hunting and gathering, and pest and disease control. It is believed that burning is more widespread in savanna and forest­ savanna environments. Tribal warfare and pyromania may be of great import locally.

PREPARATION OF THE MAPS

The maps depict the interrelations of vegetation, dry season and cultural habit of burning. Cartographic presentation of the incidence of fire and its areal distribution is accomplished by circular symbols which depict the correlation between a climatic dry season and the period of burning, (see maps). These symbols are plotted against major formations of natural vegetation. While the vegetation is

176 PATTERNS OF FIRE IN THE TROPICAL WORLD

FIG. 4. Aerial burn pattern of uncontrolled fire in open grass savanna situated at 3,500 feet elevation, Sukuma tribal area, Tanzania (2 0 30'S; 34°E). Photo by I. J. Stolberg. shown by areal patterns, the climatic dry season (an areal phenom­ enon) and burning season (a point phenomenon) are shown by point symbols. Undue emphasis should not be given to the vegetation patterns since no such bias is intended. Selection of major vegetation formations was based largely upon classifications that favored identification of vegetation by physiog­ nomic and floristic characteristics (Bartholomew, 1950; James, 1959; Waibel, 1949; Map Div. Lib. of Congr.). The rationale was that such classifications stress the composite physical characteristics of natural vegetation, which in turn, is considered a fuel matrix. Categories employed on all maps largely refer to pseudo-climax vegetation, except those of Africa. Vegetation formations used for Sub-Saharan Africa were derived from excellent recent detailed maps and reports, and therefore, present vegetation as it exists after centuries of modifi­ cation by fire (Aubreville et at., 1959; Phillips, 1965; Rattray, 1960).

177 ROBERT B. BATCHELDER

Correlation of climate and period of burning is indicated by sectors of the circular symbols (Fig. 5). The circle divided into twelve parts represents the year, in which analogous to the clock, each month represents one hour. The dry season was determined by an empirical method and is shown as a stippled sector. The period of burning is shown by a wedgeshaped sector symbol whose radius is slightly larger than the circle's. A dashed circle indicates that burning is not confined to one season, but takes place whenever a few days of dry weather permit. In all cases, the presence of the burning symbol is based on specific references in the literature to the time of burning. Circles without the burning symbol, also appear on the maps. In these cases burning may be possible and customary, but precise in­ formation was not found regarding its time of occurrence.

\3URlIIIIJC:o JAN. I PERIOD ~ FEB. I DRY PE~'\0 ". ').... -:--. NO DRY - MAR I r:::.;\': SI:ASON - APR. I ..... ,. /0J o \ , I '- _/ FIG. 5. Climatic and burning sector symbols plotted for selected stations in the tropical world.

What constitutes a dry period in the tropics potentially high in fire danger is difficult to determine. Each year, fires are reported in semi-arid tropical regions where annual precipitation may be as low as 410 mm (16 inches), and 6 to 8 months of severe drought occur. In certain humid and rainy tropics, no period can be considered dry, and annual precipitation may exceed 3,700 mm (148 inches). Never­ theless, slash and burn agriculture is practiced in which the debris is piled, and after a month of drying, can be burned on any clear day. In this case, the forest bioclimate is completely altered by opening the forest canopy. Since there is a lack of specific information on climatic condition­ ing of tropical environments, the seasonal march of temperature and rainfall have been the primary source of empirical relationships es­ tablished to determine onset and duration of a dry season. A simple

178 PATTERNS OF FIRE IN THE TROPICAL WORLD and easily applied formula is that humid months can be distinguished from ecologically dry months when average monthly precipitation expressed in millimeters is equal to or less than twice the average monthly temperature expressed in degrees centigrade (Pmrn :s; 2 Toe)'. Comparison was made of the effectiveness of this formula to iden­ tify onset and duration of a climatic dry season to that of Thornth­ waite's more complex and elaborate Water Balance (Bagnouls and Gaussen, 1953, 1957; Gaussen, 1954; Thornthwaite et al., 1955). Differences in the effectiveness of the two methods to determine onset and duration of the dry season at Ft. Lamy, Chad (Africa) are illustrated (Fig. 6). Ft. Lamy experiences a semi-arid climate and the landscape supports subarid wooded savanna (Phillips, 1965). No precipitation is recorded for the 4 months, November to May. The left-hand chart identifies the dry season to be of 8.5 months duration, mid-September to June, whereas the right-hand chart indi­ cates a dry season extending over 10.75 months, mid-August to early July. All other stations for which the two systems were compared indicated that the Thornthwaite system identified a longer dry sea­ son. Considering the number of variables involved in climatic condi­ tioning of potential fuels, however, the significance of the differences between the two methods to depict a dry season could not be judged, but is believed to be small. Therefore, the simpler method was em­ ployed in determining the ecological dry season for each station mapped.

SPATIAL PATTERNS OF TROPICAL FIRE*

Latin America.-Major types of vegetation in Latin America pre­ sent a complex pattern in which the factors of climate and relief are very significant. Major relief features are the Guiana and Brazilian Highlands, Andean Cordillera and the Central American mountains and Antillian Arch; all lie more or less transverse to prevailing sea­ sonal winds. Consequently, wet windward and drier lee-slope effects

* All maps appear at the end of this article. Indices to place names appear as separate listings facing their respective map sheets.

179 ROBERT B. BATCHELDER

THE CLIMATIC DRY SEASON The determination of the dry period according to

Bagnouls and Gaussen formula [p (mm. ) ~ 2T (OC)], left~ and Thornthwaite1s water Balance, right. Bagnouls & Gaussen Thornthwaite ---- Temperature ------Precipitation ------. Precipitation ~~ Potential evapo­ r I I I II 1111I Humid period transpiration I:·;,,;',' .;:.. ..:- .. ;1.'·1 Dry per iod -x-.""*"- Actual evapotrans- piration JIIIIIIIIII water surplus [:":;·.:;:·.' .... ·;·::·3 water deficit ~~ S~il ~oisture util- ~zat~on ~~ Soil moisture re­ charge Note: In some climographs the vertical scale above 200 mm. has been adjusted. mm. Fr. LAMY, CHA:D I 12"07'/\/ " 15"OZ'c 2.00 PPT. .. 620l71m, I \ 180 I

160

I 140 I I , I 12.0 ·c I I 50' , 100

80

60

20

o MJJASONDJ ~ F rot II JJASONDJ FIG. 6 180 PATTERNS OF FIRE IN THE TROPICAL WORLD

give rise to sharp environmental differences within short distances. Centuries of burning, first by Amerinds, and later by European settlers, have completely altered the vegetation over much of this portion of the tropical world. In Central America and the Greater Antilles Islands burning, if and when it occurs, coincides with the drier or dry season occurring during the first months of the calendar year (see Map No.8). Along the Pacific coast of the isthmian link between Mexico and South America, a pronounced dry season occurs, and burning, par­ ticularly in pastoral areas, takes place at the end of the dry season. An open deciduous forest and grassland is prevalent at low elevations and occurs as a narrow band along the Pacific Ocean, but could not be shown due to the small-scale of the map. Although little specific data was available, it is known that shifting cultivators and sedentary farmers burn the subtropical montane forests on slopes at higher elevations. Along the east coast at T uxtala, Mexico (3), for example, burning of the humid tropical forest occurs at the end of a brief dry season extending from March to May. Merida, Mexico (5) experiences a semi-arid climate, and the burning of dry forest scrub and grass is from mid-February to May. At Belize, British Honduras (9) burning, in the rainforest, largely by 1\1aya Indians, takes place from mid-February to April, as soon as the rains lessen since the drier period is brief and is frequently interspersed with showers. Burning occurs even in perhumid climates; note Puerto Cabezas (12) and Bluefields (13), Nicaragua, where annual precipitation totals exceed 3,000 mm (120 inches) and 4,000 mm (160 inches) respec­ tively. Data was not available for many stations but burning in the highlands of Central America and in parts of Haiti and the Domini­ can Republic is known to be widespread. In South America, so ubiquitous is fire, that very few specific references describe in detail the times or purpose for burning. Unfor­ tunately only 11 stations for all of South America could be plotted with a burning symbol; note Formosa (63) and Goias (62) Brazil where burning is related to pastoral activity. At St. Ignatius (39) and Tumeremo (34), the period of burning refers to shifting cultivation by Caribs in the Rupununi District of Guyana. (see Maps Nos. 9 and 10). At San Fernando de Apure, Venezuela (27) the reference

181 FIG. 7. Fire and smoke plumes in open park savanna of the Llanos, Apure State, Venezuela. Note gallery forest and second fire in center of photo near horizon. Photo by T. L. Hills. is to the practices of the Yaruro Indians, and burning of the savannas at the end of the dry season by graziers. (Figs. 7 and 8). Use of fire in certain localities is known to be increasing (Fig. 9). For exam­ ple, hitherto thinly populated lower foothills along the eastern flanks of the Colombian and Peruvian Andes are experiencing a sig­ nificant influx of settlers accompanied by widespread removal of forest. Elsewhere, as in the Sierra Nevada de Merida of Venezuela, population pressure has disastriously shortened the forest-fallow pe­ riod. Unfortunately, controlled use of fire in forest and range man­ agement in South America has made little headway in tropical coun­ tries. Tropical Asia and Northern Australia.-The spatial and temporal patterns of burning in tropical Asia and northern Australia reflect centuries of occupation under systems of intensive subsistence agri­ culture, plantation agriculture, grazing, both nomadic and com­ mercial, swidden agriculture, and hunting and gathering. (see Map No. 12). Consequently, much of the original vegetation has been transformed to cropped and grazed land and second-growth forest. Nine vegetation types are depicted. Cultural burning practices of the

182 FIG. 8. Flush of new growth (Tracbypogon plumosus) following burn on the right, and unburned two-year growth on the left, in which a jeep track acted as a firebreak. Northern Rupununi, Guyana. Photo by T. L. Hills. various ethnic groups may be to burn at certain seasons, but aban­ doned clearings in the degraded forest are overgrown with bamboo and grasses which will support sweeping fire almost anytime. The pattern of burning in the forested environment, which in­ cludes the montane forest and grassland, the tropical rainforest, and the moist semi deciduous forest, epitomizes the complexity resulting from varied physical conditions and diverse cultural practices. Nu­ merous stations in the equatorial zone, have no climatic dry season although brief periods of less rainfall occurs. The season of burning, however, is extremely varied in this zone. Burning occurs all year in Madang, New Guinea (65) and Buntok, Borneo, Indonesia (40). A dual burning season is found in J esselton, Sabah (32). Obviously advantage is taken of "breaks" in the rains that occur during the transitional period when the monsoon wind circulation is changing direction. Most of the remaining stations that have no dry season burn for two or three months; e.g. the following locations in Indo­ nesia: Manado (44), August to October, Pontianak (39), May to July, Lahat (35), August to November, and Padang (34), the month of October. It should be borne in mind that the rugged topography

183 FIG. 9. Scattered brush savanna with gallery forest and palm marsh. Irregular dark patterns on the rolling terrain are recently burnt areas. The darker tone of the burnt areas is believed to be due to the surface coloring of reddish latosols. Rio Bianco Savanna, Brazil. Photo by T. L. Hills. of the islands and the monsoon circulation give rise to pronounced environmental contrasts within distances of a few kilometers. The islands of Java, Sulawesi, and Timor have distinct dry seasons of up to seven months duration, and burning occurs in the montane forests during the dry season; e.g. Kendari (43), Kupang (45), and Makassar (42). In northern Australia the climatic dry seasons are considerably longer, yet tropical rainforest persists along the coast. The burning season is longer than the dry season at Crooktown (61) and Darwin (57). At the latter two stations, burning before the last rains have ceased may be to prevent accumulation of fuel in forests, while burning late in the dry season may be part of a program of pasture management. The forested environment in India and mainland Southeast Asia, has a climatic dry season that lasts up to eight months, October to May (see Map No. 11). For much of this area the use of fire is asso­ ciated only with swidden cultivation and occasional hunting in the uplands and hills, and pyromania. Most of the level land and river valleys are in permanent paddy rice cultivation where fire is re­ stricted to the burning of rice stubble not fed to animals.

184 PATTERNS OF FIRE IN THE TROPICAL WORLD

In India, fire is employed in remote portions of the Central Indian Hills at Bhopal (8), Raipur (9), Ranchi (11). Burning at Comilla, East Pakistan (13), Toungoo, Burma (16), and Luang Prabang, Laos (21) is carried on by remote ethnic groups in planting upland rice. The burning takes place near the end of the dry season, after the forest has been felled and allowed to dry. A noteworthy excep­ tion is near Poona, India (7), where the early dry season burning pattern reflects control burning in teak forests. Control burning of forest and pasture lands occurs principally in the teak forests of India, Burma and Thailand. In northern Aus­ tralia, control burning is used by cattle and sheep raisers, to maintain range against brush encroachment. Control burning is also employed in eucalypt and other dry forests to reduce fire hazard. Sub-Saharan Africa and Madagascar.-Burning in sub-Saharan Africa and Madagascar is closely related to cultural traditions en­ vironmentally conditioned. The cultural factor is dominant in tall forest environments where the climate has no ecologically dry period; that is, no month occurs in which average precipitation is less than 25 mm. In the Congo Basin, westward along the Gulf of Guinea, and eastward into East Africa, the symbols reveal a sur­ prising diversity in time of burning (see Map No.6). For example, at Lidja, Congo (Leopoldville) (78), burning may occur at any time, while at Port Francqui (77), it occurs in July and August. September and October is the period of burning at Kindu (80), but burning takes place in December and January at Stanleyville (75). At Ambam, Cameroon (38), burning occurs in both the wet and dry seasons. In the highlands of East Africa, Usumbura, Burundi (84), and Bukavu (81) across the border in Congo (LeopoldviIle), experience similar dry season, but burning takes place at opposite times of the year. Clearly, time of burning in humid forests depends largely on human action in felling or killing trees. Numerous writers assert that there is no climatic factor directly controlling the time of burning in tropical rainy (Af) climatic areas. Peripheral to the Congo Basin and the Guinea Coast, transition occurs in both climate and natural vegetation. Rainfall records indi­ cate no distinct dry season, but one to three months may be ecologi­ cally dry. Shifting cultivation has degraded the tall, semideciduous

185 ROBERT B. BATCHELDER forest so that forest and grass or brush covered abandoned clearings coexist as a mosaic. South of the Congo Basin, burning takes place at the end of the drier season and extends into the period of first rains. Topographic relief and elevation appears to exercise little direct influence, as indicated by Kabalo, (82), Lusambo (79), Kikwit (76), (all in Congo Leopoldville), and Brazzaville, Congo (Brazzaville) (95). North of the Congo Basin in Nigeria, there are distinct differences in the periods of burning related to cultural activity (see Map No.5). At Enugu (32) and Ibadan (31), for example, both stations are lo­ cated in the forest savanna mosaic and experience identical dry pe­ riods both as to time of occurrence and duration. Yet at Ibadan, burning takes place from November to mid-February and again in July, whereas at Enugu fires are most frequent during mid-January to March. The explanation is that adjacent grasslands are fired during the dry season and at onset of first rains. On the other hand, shifting cultivators clear and burn either in December and January or in July, depending on whether hunting and gathering are important activities in the life of the people. The period of burning could not be plotted for other stations in the West African forest-savanna mosaic, but it is known that burning early in the dry season is an official government forest policy in which control burning is used to remove a highly flammable ground covet. Forest-savanna mosaic is also found along the southeast coast of Africa and the western coast of Madagascar (see Map No. 7). In­ direct evidence suggests that the period of burning in these areas is during the last shower weather before onset of the dry period and extending as well into the dry season. Because no specific references to the burning period were available, the sector is not shown for stations in these areas. Wooded savannas of various types are widespread in Africa. At most stations, the dry season is well-defined, with ecologically dry months varying from 3 to more than 6. Occurrence of fire is frequent but specific references to burning are surprisingly few and so vague, that one may conclude that an entire area goes up in flames each year. The period of burning at most stations, however, is shorter than the dry period.

186 PATTERNS OF FIRE IN THE TROPICAL WORLD

Burning in wooded savannas reflects both primitive cultural prac­ tices and control burning policies. South of the Congo Basin, the preferred burning period is at the end of the dry season or during the first showers of the rainy season. The period of burning reflects policies based on ecological studies of the effects of fires on grass­ lands and wooded areas. For a number of reasons, burning late in the dry season is both of frequent occurrence and the recommended practice (see stations 111, 113, 110, 107, 109, and 106). In northern wooded savannas at Tibati, Cameroon (153) burning occurs early in the dry season, and reflects use of fire to promote regeneration of woodlands (see Map No.6). Also, primitive culti­ vators frequently burn early preparatory to gathering and hunting expeditions in adjacent forests. Mid-dry season burning occurs at Bouca, Central African Re.public (41), which is related to pastoral and farming activity. At Wau, Sudan (50), which experiences a simi­ lar dry season, burning occurs in any season and is related to domi­ nantly nomadic pastoral activity. In the eastern highlands of Africa, north and east of Lake Victoria, burning occurs in relation to agri­ cultural calendars of shifting and sedentary farmers rather than solely to climate; e.g. Juba, Sudan (53), Kitgum, Uganda (61), and Na­ kuru, Kenya (65). Part of the reason for burning extending one or more months into what appears to be a rainy season is that there occurs a period of brief showers prior to onset of heavy rains. Specific references to burning in the open grasslands located both north and south of the equator are very few. Part of the reason is that rainfall variability is great in the drier climates associated with the geographic distribution of these grasslands and burning is possi­ ble nearly half of the year. Pastoral activities both nomadic and commercial occur, as well as primitive cropping and commercial irrigation and dry farm agriculture. Because of the diversity of land use, it is probable that some burning is taking place within an area during most of the dry season. Examples would be burning of com­ mercial cotton stubble following harvest, later burning of pasture grasses by nomadic herdsmen who will return to a flush of new grass after first rains, burning late in the dry season by commercial graziers for the same reason, and clearing of wooded areas for swidden agriculture by primitive cultivators. To the uninitiated it

187 ROBERT B. BATCHELDER may well seem that burning occurs everywhere during the dry sea­ son. In a sense this is true; but burning is not necessarily chaotic or random as is too frequently inferred from the literature.

DISTRIBUTION OF TRENDS IN BURNING

The geographic patterns of burning in relation to climate and vegetation have been described and interpreted. It must be remem­ bered, however, that the maps are static. They do not convey the direction of changes that are taking place in the incidence and dis­ tribution of fire. What are the trends in the use of fire in the tropical world? What are the differences from place to place in these trends? Man's use of fire in the tropical world is no longer in the stage of "ecological climax," wherein a stable, harmonious relationship to the environment exists. The impact of the Western culture has set in train a process that has led to rapid changes in the environment, and destroyed the old balance between man and nature, (Watters, 1960). Thus the specific conformation of the interrelations of man, land, and fire in any particular area can be seen as stages along a continuum of change. At one end are the areas just emerging from "ecological climax," with relatively little population increase, rela­ tively long periods of forest fallow, and relatively little soil erosion and forest or pasture degradation. The highlands of New Guinea and the interior rainforests of the Amazon Basin are representative of this stage. Near the middle of the continuum are areas in "eco­ logical disequilibrium," in which population growth, changes in value systems, soil erosion, and forest and pasture degradation have created a critical situation. Shortages of food in the rural areas have led to widespread undernourishment, accelerated deterioration of the land, and migration of rural people to cities. Many areas of tropical Africa and Latin America are representative of this stage. At the other end of the continuum, in the stage of "ecological rehabilitation," are the areas in which the application of scientific knowledge and techniques has resulted in the use of fire as an instrument of forest and grassland management. Representative of this stage in the continuum are those areas in East and South Africa, parts of India, Burma, Thailand and Australia where control burning is used with adequate safeguards

188 PATTERNS OF FIRE IN THE TROPICAL WORLD

against escape of fire and a tested year-by-year plan of fire use. A degree of caution should attend application of this concept of ecological continuum. The principal reasons are that there is spatial intermixture or interdigitation of areas of differing positions; and, individual areas will occupy either a broad or a narrow segment of the continuum, depending on the scale or level of generalization. It should also be noted that most areas of "ecological rehabilitation" are found where Europeans have settled lands that never passed through "ecological disequilibrium." Indeed, only one case is known where primitive use of fire has been partly modified by the intro­ duction of modelin technology. This is the "teak taungya" system first developed in Burma, and now used in India and elsewhere in Southeast Asia. However, the concept can be useful in determining planning and policy needs. That certain parts of the tropics are experiencing more extensive and intensive alteration of the natural landscape by fire is well docu­ mented. Use of fire and its effects appear to have declined in Oceania and parts of South and Southeast Asia, notably India. Here, agricul­ tural populations have become sedentary, while primitive cultivators represent minorities located in remote geographic areas. On the other hand, cultural use of fire is increasing in much of Africa and parts of tropical and subtropical Latin America. The rate of population in­ crease is high, particularly among rural peoples, and new lands are being sought for clearing by expanding populations. It is clear that for much of the tropical world, the effects of fire on the natural and cultural environment are increasing at an increasing rate. It is hoped that this attempt to cartographically portray the incidence and distribution of fire in the tropics may prove helpful to scholars and administrators, who are deeply concerned about the increase in recent decades of widespread, indiscriminate burning, yet who recognize that fire is an effective low cost means by which tropical environ­ ments can be managed for maximum use. LITERATURE CITED Aubreville, A. P. Duvigneaud, A. C. Hoyle, R. W. J. Keay, F. A. Mendonca, and R. E. G. Pichi-Sermolli. 1959. Vegetation map of Africa south of the Tropic of Cancer, Scale 1: 10,000,000. Published for L'Association pour l'Etude Taxo­ nomique de la Flore d'Afrique Tropicale, with assistance of U.N.E.S.C.O. Oxford Univ. Press. Explanatory notes by R. W. J. Keay.

189 ROBERT B. BATCHELDER

Bagnouls, F. and H. Gaussen. 1953.. Periode de secheresse et vegetation, C. R. Ac. Sci. 236, No. 10: 1075-1077. Bagnouls, F. and H. Gaussen. 1957. Les climats biologiques et leur classification, Ann. de Geopraphie. 66(355): 193-220. Bartholomew, John. 1950. The advanced atlas of modern geography. McGraw-Hill, New York; Meiklejohn, London. 108 pI. and Index, 47 pp. Boughey, A. S. 1963. Evolution of termite mounds in Central Africa, Proceedings of the Central African Scientific and Medical Congress held at Lusaka, Northern Rhodesia, August 26-30, 1963, pp. 333-341. Gaussen, H. 1954. Theories et classification des climats et microclimats, Congres Internat. Bot., Sect. 7 et 3: 125-130. James, Preston E. 1959. Latin America. 3 ed., Odyssey Press, New York. 942 pp. Library of Congress, Map Division, Washington, D. C. Phillips, John. 1965. Fire-as master and servant: its influence in the bioclimatic regions of trans-Saharan Africa. Fourth Ann. Tall Timbers Fire Ecol. Conf. Proc. Tall Timbers Res. Sta. Tallahassee, Florida. pp. 7-109. Rattray, J. M. 1960. The Grass Cover of Africa. FAO Agric. Stud. No. 49, Food and Agr. Org. of the United Nations. Rome, Italy. 168 pp. with map, 1:10,000,000. Richards, P. W. 1964. Personal Communication. Stewart, O. C. 1956. Fire as the first great force employed by man. In Thomas, W. L. Jr., Man's Role in Changing the Face of the Earth. Univ. of Chicago Press, Chicago. pp. 115-133. Thornthwaite, C. W. and J. R. Mather. 1955. The water balance. Pub!. in Climatology. Laboratory of Climatology, Vo!' 8(1) :104 p. Waibel, Leo. 1948. Vegetation and land use in the Planalto Central of Brazil Geog. Rev., 38, No. 4:529-554. Watters, R. F. 1960. The nature of shifting cultivation: a review of recent research. Pacific Viewpoint. 1, No. 1:59-99. Wijmstra, T. A. and T. van der Hammen. 1965. Palynological data on the history of tropical savannas in northern South America. Unpublished report, 30 p.

190 MAPS OF BURNING IN RELATION TO CLIMATE AND VEGETATION

191 INDEX TO CLIMATIC STATIONS

Map of Africa, Sheet 1

Station Number

1 Atar, Mauritania 29 Sokoto, Nigeria 2 Boutilimit, 30 Kaduna, 3 Nema, 31 Ibadan, 4 St. Louis, Senegal 32 Enugu, 5 Dakar, 33 Fort Lamy, Chad 6 Matam, 34 Abecher, 7 Kaolack, 35 Fort Archambault, Chad 8 Tambakounda, 36 Marua, Cameroon 9 Conakry, Guinea 37 Yaonde, 10 Kankan, 38 Ambam, 11 Monrovia, Liberia 39 Birao, Central Afr. Rep. 12 Bouake, Ivory Coast 40 Ndele, 13 Gagnoa, 41 Bouca, 14 Abidjan, 42 Bangui, 15 Tabou, 43 Bangassou, " 16 Tesalit, Mali 76 Kikwit, Congo (Leo.) 17 Tomboctou, Mali 77 Port Francqui, Congo (Leo. J 18 Menaka, 91 Lambarene, Gabon 19 Bamako, 92 Mayoumba, 20 Bobo Dioulasso, Upper Volta 93 Impfondo, Congo (Brazz.) 21 Ougadougou, 94 Gambona, 22 Natitingou, Dahomey 95 Brazzaville., 23 Tamale, Ghana 96 Cabinda, Angola & Cabinda 24 Kumasi, 97 Sao Salvador, 25 Lome, Togo 98 Luanda, 26 Agades, Niger 99 Casanha, 27 Niamey, 100 Sunginge, 28 Zinder, 152 Bo, Sierra Leone 153 Tibati, Cameroon 154 Bida, Nigeria

192 20

10

BURNING IN RELATION TO o CLIMATE AND VEGETATION AFRICA Sheet I of 3 o 500km ======

m MONTANE FOREST AND GRASSLAND t:;;.~-~ SAVANNA GRASSLAND ~~€~ TROPICAL RAINFOREST m SEMI-ARID SHRUB AND GRASS

I;!;:~ FOREST-SAVANNA MOSAIC XEROPHYTIC EVERGREEN BRUSH AND THICKET

fEE~ MOIST SUBHUMID WOODED SAVANNA f~r(~;§%~ DESERT VEGETAT ION

~-_-_-~ DRY SUBHUMID WOODED SAVANNA ~~;ill SUBTROPICAL GRASSLAND ;'.,,J..;. ....:.,

10

10 10

193 INDEX TO CLIMATIC STATIONS Map of Africa, Sheet 2

Station Station Number Number Name

33 Fort Lamy, Chad 72 Buta, congo (Leopoldville) 34 Abecher, 73 Paulis, 35 Ft. Archambault, Chad 74 Irumu 36 Marua, cameroon 75 Stanleyville, 37 Yaonde, 76 Kikwit, 38 Ambam 77 Port Francqui, 39 Birao, Cent. Afr. Rep. 78 Lodja, 40 Ndele, 79 Lusambo, 41 Bouca, 80 Kindu, 42 Bangui, 81 Bukavu, 43 Bangassou, 83 Kamina, 44 El Fasher, Sudan 84 Usumbura, Burundi 45 Khartoum, 85 Bukoba, Tanzania 46 Wad Medani, 86 Tabora, 47 Kassala, 87 Dodoma, 48 Roseires, /I 88 Dar es Salaam, Tanzania 49 Raga, 90 Songea, 50 Wau, 91 Lambarene, Gabon 51 Malakal, 92 Mayoumba, 52 Akobo, 93 Impfondo, Congo (Brazzaville) 53 Juba, 94 Gambona, 54 Addis Ababa, Ethiopia 95 Brazzaville, 55 Burao, Somalia 96 Cabinda, Angola & Cabinda 56 Obbia, 97 Sao Salvador, 57 Belet-Uen, Somalia 98 Luanda, 58 Afgoi, 99 Casanha, 59 Bardera, 100 Sunginge, 60 Chisimaio, 101 Benguela, 61 Kitgum, uganda 102 Chitembo, 62 Mubende, 105 Villa Teixera, 63 Moyale, Kenya 106 Balovale, Zambia 64 Mandera, 107 Ndola, 65 Nakuru, 1'10 Kasama, 66 Nairobi, 111 Karonga, Malawi 67 Garissa, 112 Lilongwe, 68 Lamu., 113 Maniamba, Mozambique 69 Malindi, 151 Dire Dava, Ethiopia 70 Voi, 71 Mombasa,

194 50

o

10 BURNING IN RELATION TO CLIMATE AND VEGETATION AfRICA Sheet 2 of 3 o-=====-====1 500km

MAP No6 10

J95 INDEX TO CLIMATIC STATIONS

Map of Africa, Sheet 3

Station Number

68 Lamu, Kenya 114 Nampula, Mozambique 69 Malindi, Kenya 115 Chemba, 70 Voi, 116 Mabote, 71 Mombasa, 117 Pafuri, 76 Kikwit, conqo (Leo.) 118 Salisbury, Rhodesia 119 Bulawayo, 77 Port Francqui J :: 78 Lodj a, 120 Tsumeb, Southwest Africa 79 Lusambo, 121 Windhoek, 80 Kindu, 122 Gobabis, 81 Bukavu, 123 Keetsmanshoop, " 82 Kabalo .• 124 Maun, Bechuanaland 83 Kamina, 125 Serowe, 84 Usumbura, Burundi 126 Kanye, 86 Tabora, Tanzania 127 Pietersburg, South Africa 87 Dodoma, 128 Carolina, 88 Dar es Dalaam, Tanzania 129 Kuruman, 89 Lindi, 130 Upington, 90 Songea, 131 Kimberley, 92 Mayoumba, Gabon 132 Beaufort West, 95 Brazzaville, Congo (Brazz.) 133 Graff Reinet, 96 Cabinda, Angola & Cabinda 134 Pietermaritzburg, 97 Sao Salvador, 135 Masaru, Basutoland 98 Luanda, 136 Stegi, Swaziland 99 Casanha, 137 Dzaoudzi, Malagasy 100 Sunginge, 138 Diego Suarez, Malagasy 101 Benguela, 139 Antalaha, 102 Chitembo, 140 Mandritsara, 103 Sa'da Bandeira, 141 Marovoay, 104 Mupa, 142 Maintirano, 105 Villa Teixera, 143 Tamtave, 106 Balovale, Zambia 144 Tananarive, 107 Ndola, 145 Morondava., 108 Livingstone, Zambia 146 Beroroha, 109 Lusaka, 147 Tulear, 110 Kasama, 148 Farafagana, Malagasy III Karonga, Malawi 149 Tsihombe, 112 Lilongwe, 150 Fort Dauphin, 113 Maniamba, Mozambique

196 50

10 10

lsa

20

BURNING IN RELATION TO "30 CLIMATE AND VEGETATION- AFRICA Sheet :3 of ::; O_======~5~OOkm

MAl" No 'I 10 20 30

197 INDEX TO CLIMATIC STATIONS

Map of Central America

Station Name of Number Station Country

1 Tampico Mexico 2 Ometepec 3 San Andres Tuxt1a 4 Tuxtla Gutierrez 5 Merida 6 Cozumel 7 Flores Guatemala 8 Amatitlan 9 Belize British Honduras 10 San Salvador E1 Salvador 11 Tegucigalpa Honduras 12 Puerto Cabezas Nicaragua 13 Bluefields 14 San Jose Costa Rica 15 Cristobal Panama 16 Balboa Heights C. Z. 17 Habana Cuba 18 Gibara 19 Kingston Jamaica 20 Port-au-Prince Haiti 21 Puerto plata Dominican Republic 22 Barahona 23 Santo Domingo

198 90 80

20

BURNING IN RELATION TO CLIMATE AND VEGETATION CENTRAL AMERICA o 500km I======:::::::::fl

MONTANE FOREST AND GRASS­ SAVANNA GRASSLAND LAND SEMI-ARID SHRUB AND GHASS TROPICAL RAINFOREST ~ MAP No 8 MONTANE PINE-CEDAR FOREST

80 10

199 INDEX TO CLIMATIC STATIONS

Map of South America, Sheet 1 station Name of Number Station Country

24 Cartagena Colombia 25 Tolu 26 Barrancabermeja 27 Choconta 28 popayan Florida 29 Maracaibo Venezuela 30 Barinas 31 Puerto Cabello 32 San Fernando de Apure 33 Aragua de Barcelona 34 Tumeremo 35 Santa Elena 36 San Carlos de Rio Negro 37 Trinidad Trinidad & Tobago 38 Georgetown Guyana 39 st. Ignatius 40 Cayenne French Guiana 41 Guayaquil Ecuador ·42 Piura Peru 43 Agua Caliente " 44 cuzco 45 Riberalta Bolivia 46 Santa Cruz 47 Villa Montes 48 Puerto Suarez 49 Mariscal Estigarribia Paraguay 50 Sao Gabriel do Rio Negro Brazil 51 Manaus 52 Manicore 53 Porto Velho 54 Alto Tapajoz 66 Bella Vista

200 80

o

BURNING IN RELATION TO CLIMATE AND VEGETATION SOUTH AMERICA Sheet I of 2 o 500km

MONTANE FOREST AND E3 OPEN WOODED SAVANNA III GRASSLAND ~ ~~~:1 TROPICAL RAINFOREST ~ SAVANNA GRASSLAND '!j-t;."t.i. ~ MOIST SEMI-DECIDUOUS SEMI-ARID SHRUB AND ;,..,-" /' FOREST mJ~- m +-;. .... +1 DRY DECIDUOUS FOREST DESERT VEGETATION I; +:...... AND SHRUB ~~{I~g

~"'..T""'g DRY DECIDUOUS OPEN ~::: WOODLAND AND SHRUB

N o 80 70 ...... INDEX TO CLIMATIC STATIONS

Map of South America, Sheet 2

station Name of Number Station Country

33 Aragua de Barcelona Venezuela 34 Tumeremo 35 Santa Elena 37 Trinidad Trinidad & Tobago 38 Georgetown Guyana 39 st. Ignatius 40 Cayenne French Guiana 45 Riberalta Bolivia 46 Santa Cruz 47 Villa Montes 48 Puerto Suarez 49 Mariscal Estigarribia Paraguay 51 Manaus Brazil 52 Manicore 53 Porto Velho 54 Alto Tapajoz 55 Tracatena 56 Carolina 57 Terezina 58 Santa Rita do Rio Preto 59 Mondubim 60 Natal 61 Pesqueira 62 Goias 63 Formosa 64 Teofilo Otoni 65 Araguari 66 Bella Vista 67 Itajuba

202 OZ ...... 0 Z~ ..E 0 Ow 0 c:t It) ~(!) (,) a:: (\I ...JW I.&J W> :::& 'ti C:::o c:t (\I :x:: ...... ZZ I- .J: -<1: ;:) If) 0 (!)W U) 0 Z~ 0:::_Z::2: :::>...J 000

203 INDEX TO CLIMATIC STATIONS

Map of South India and Southeast Asia

Station Name of Number Station Country

1 colombo Ceylon 2 Trincomalee 3 cochin India 4 Negapatam 5 Bangalore 6 Hyderabad 7 Poona 8 Bhopal 9 Raipur 10 Vizianagram 11 Ranchi 12 Calcutta 13 Comilla Pakistan 14 Akyab Burma 15 Mandalay 16 Toungoo 17 Rangoon 18 Bangkok Thailand 19 Surin 20 Muang Khon Kaen 21 Luang Prabang Laos 22 Chapa North Vietnam 23 Hanoi 24 Hne South Vietnam 25 Nhatr?-ng 26 phnom Penh Cambodia 27 Macau Macau (Port.) 28 Kota Bharu Malaysia 29 Kuala Pana 30 Kuala Lumpur 31 Kuching 32 Jesselton 33 Takingeun Indonesia 34 padang 35 Lahat 36 Djakarta 37 Surabaja 38 Assembagus 39 Pontianak 40 Buntok

204 20

10

o BURNING IN RELATION TO CLIMATE AND VEGETATION SOUTH INDIA AND SOUTHEAST ASIA O~",======.,;5;;;;;OOkm

MONTANE FOREST AND GRASS­ DRY SEMI-DECIDUOUS FOREST LAND

SEMI-ARID WOODLAND fu~D TROPICAL RAINFOREST ~~{:i~l THORN SHRUB

~;::~ MOIST SEMI-DECIDUOUS FOREST SEr.!I-ARID SHRUB AND GRASS + .+

110 MAP No 11

205 INDEX TO CLIMATIC STATIONS

Map of Southeast Asia and Northern Australia

Station Name of Number station Country

19 Surin Thailand 20 Muang Khon Kaen 24 Hue south Vietnam 25 Nhatrang 26 Phnom Penh Cambodia 28 Kota Bharu Malaysia 31 Kuching 32 Jesselton 34 Padang Indonesia 35 Lahat 36 Djakarta 37 Surabaja 38 Assembagus 39 Pontianak 40 Buntok 41 Balikpapan 42 Makassar 43 Kendari 44 Manado 45 Kupang 46 Manokwari 47 Mappi 48 Laoag Philippines 49 Manila 50 Tuguegarao 51 Iloilo 52 Dumaguete 53 Davao 54 Port Hedland, W.A. Australia 55 Nullagine, W.A. 56 Broome, W.A. 57 Darwin, N. T. 58 Daly waters, N.T. 59 Alice Springs, N.T. 60 Croydon, Qld. 61 Crooktown, Qld. 62 Emerald, Qld. 63 Daru, papua 64 Port Moresby, Papua 65 Madang, New Guinea

206 130 140 150 II MONTANE FOREST AND GRASSLAND ~: 7"·::)1 TROPICAL RAINFOREST MOIST SEMI-DECIDUOUS FOREST 10

DRY SEMI-DECIDUOUS FOREST ~'-, ':'"'

~-.Ai.Y SEMI-ARID WOODLAND AND THORN ~~- SHRUB OPEN WOODED SAVANNA ~--_. ,,-- SAVANNA GRASSLAND ~.~--..:. . [II SEMI-ARID SHRUB AND GRASS ~ DESERT VEGETATION 0

BURNING IN RELATION TO CLIMATE AND VEGETATION SOUTHEAST ASIA AND NORTHERN AUSTRALIA

oo 500 km

207