Forest Ecology

Chris Ebling Texas Master Naturalist

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 What is ecology, and specifically forest ecology?  What is an ecosystem, and specifically a forest ecosystem?  Processes associated with living and nonliving elements within a forest ecosystem.  Basic components and structure of a forest ecosystem.  Different forest ecosystem/types and factors that contribute to the differences.

 The study of living organisms and their relationship to their environment

 Greek oikos (house) + German logie (study)

 Physical environment  Geography, climate, soils, etc.

 Intra-species relationships  Social structure

 Interspecies relationships  Competition  Forest Ecology – study of the relationships between living organisms and non-living factors in a forest

 An ecosystem is a dynamic set of living organisms (plants, animals and microorganisms) all interacting among themselves and with the environment in which they live (soil, climate, water and light).

 An ecosystem does not have precise boundaries

 As small as a pond or a dead tree

 As large as the Earth itself  An ecosystem can also be defined in terms of its vegetation, animal species or type of relief

 Forest: "an ecosystem characterized by a more or less dense and extensive tree cover, often consisting of stands varying in characteristics such as species composition, structure, age class, and associated processes, and commonly including meadows, streams, fish, and wildlife  Forests include special kinds such as industrial forests, non-industrial private forests, plantations, public forests, protection forests, and urban forests, as well as parks and wilderness." - Society of American Foresters

 All terrestrial ecosystems depend on solar energy as the primary energy source.

 Others energy sources?  Primary productivity is the result of energy captured by producers, such as

First Law of Thermodynamics! plants.  Some of this energy is lost when producers use sunlight energy for respiration.

 Only a portion of the energy captured by producers is passed on to consumers.

 Rule of thumb – 90% of energy is lost in transfers between trophic levels.

 Consumers also lose energy due to respiration.  Note that the energy flow through an ecosystem is one way. Copyright ® 1999. Elizabeth Anne Viau

 All water begins in the oceans  All water returns to the oceans  What is the most potent common greenhouse gas in our atmosphere?  What happens as the atmospheric temperature increases?

 Remember your physics! Source: USGS

 Warmer air can hold more gaseous water

 Most of the atmosphere is comprised of N2  Most of the nitrogen in the atmosphere is unavailable for use by organisms.  The strong triple bond between the N atoms in N2 molecules makes it relatively inert.  For plants and animals to be able to use nitrogen, N2 gas must first be converted (“fixed”) to more a chemically available form such as ammonium © 1999-2007 Michael Pidwirny (NH4+), nitrate (NO3-), or organic nitrogen (e.g. urea - (NH3)2CO).

 Gliricidia sepium

 A deciduous tree in the Leguminosae family

 Used in Malawi as part of agroforestry initiatives

 Fixes nitrogen in the soil

 Loses its leaves during the crop season

 3X to 4X increase in maize production!

 The incorporation of carbon dioxide into living tissue by photosynthesis and its return to the atmosphere through respiration, the decay of dead organisms, and the burning of fossil fuels Source: Youcontrol-cllimatechange.co.uk Carbon Storage  Carbon is stored in major sinks  Organic molecules in living and dead organisms found in the biosphere;  Carbon dioxide in the atmosphere;  Organic matter in soils;  Lithosphere as fossil fuels and sedimentary rock deposits such as limestone, dolomite and chalk;  The oceans as dissolved atmospheric carbon dioxide and as calcium carbonate shells in marine organisms.

 What is the problem with burning fossil fuels?  Massive release of stored carbon

 What happens as the oceans warm?  Remember your physics!  Reduced capacity to hold dissolved gasses

Forests Ecosystems are Three Dimensional

 Dominant species that extend through the canopy  Evident in rainforests  White Pine forest in Northern Michigan

 What are the advantages and disadvantages of being emergent?

 Highest continuous level in the forest

 Contains mature trees

 What is the advantage of being in the canopy?

 Contains  Tree saplings  Small shade-tolerant trees  dogwood, redbud  Tall shrubs

 What is the strategy of understory trees?

 The herb/fern layer

 Ranges from the ground surface to about 3'  Tree seedlings, herbs, ferns, grasses

 Decaying plant and animal matter

 Fungi, mosses & lichens

Does the forest ecosystem end at the forest floor?

 Soil Horizons

 A layer parallel to the soil surface, whose physical characteristics differ from the layers above and beneath.  Soil Structure

 The way individual particles of sand, silt, and clay are assembled.  Affected by:

 Basal geology

 Climate

 Water Movement.

 Organic Matter Content

Trees Communicate via Root Systems and Fungal Networks

 Stand density

 A measure of the stocking rate of trees in a forest

 Measured by:  Trees/acre  Basal area/acre  Crown cover

Time

Source: Ohio State University Extension Service

 Forest succession is the temporal transition of vegetation societies at the same place after major changes in environmental conditions (e.g. glaciation, fires, clear cut logging).  If it starts from a vegetation-free area, it passes through a certain sequence of societies initiated by pioneer-societies, followed by intermediate stages up to the final climax society.  The climax society can only develop if no other disturbance interrupts the development.  Succession has a great impact on wildlife populations  White Tailed Deer – Elk  Kirtland’s Warbler  Require 4 to 20 year old Jack Pine trees for nesting  Dependent on fire to reset forest succession  Jack Pine only reproduce after a fire.

 Climate

 Temperature  Range and seasonality  Eg. Texas vs. Brazil

 Rainfall  Amount and seasonality  Eg. Texas vs. Brazil  Sunlight

 Intensity and seasonality  Rainforest vs. Northern Boreal Forest  Geography

 Latitude

 Altitude  Mimics latitudinal differences  Davis mountains

 Geology

 Soil type  Rocky, sandy, acidic, basic, nutrient availability, etc.  Eg. Transition from Blackland Prairie to Piney Woods.  Disruption

 Fire

 Animal/insect activities

 Human activities

 Texas has more than 12 million acres of forestland concentrated in 43 counties in East Texas  Sixty-two percent of Texas' forestland is owned by non- industrial private landowners.  32% is owned by industry.  The public (federal or state forests) owns the other 6%  Four National forests  Five State forests  Over 200 tree species are

considered native to Texas Source: Texas Forest Service

 Texas National Forests  Texas State Forests

 Angelina  I.D. Fairchild

 Davey Crockett  Masterson

 Sabine  John Henry Kirby

 Sam Houston Memorial  E.O Siecke

 W. Goodrich Jones