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GEOGRAPHY 4371: FOREST GEOGRAPHY
I. INTRODUCTION
Note: Read chapters 1, 2 and 3 of Kimmins (2004).
FOREST DYNAMICS: THE BACKGROUND AND THE APPROACH
Goal: to place the content and approach of this course into the broader contexts of ecology and
vegetation science.
The subject matter of Ecology includes:
1. individual organisms in relation to other organisms and the nonliving (abiotic) environment;
2. groups of organisms of the same species (populations);
3. natural assemblages of populations of different species (communities);
4. entire natural systems composed of communities and their physical environment
(ecosystems).
SUBDIVISIONS OF ECOLOGY (with particular reference to forest ecology)
1. Autecology
Plant autecology is the study of the influence of the environment on a single individual or
species. It is concerned with explaining environmental controls on a species distribution by
considering physiological, phenological and genetic traits that allow a species to be successful
in a particular habitat. (Phenology = the timing of behavior in relation to environmental cues; for
example, timing of pollination, flowering, seed dispersal, leaf growth, stem growth, etc.)
Subdivisions of autecology include evolutionary ecology (genecology, demecology),
population ecology (plant demography), and physiological ecology (ecophysiology).
2. Synecology
Plant synecology is the study of plant communities and the interaction of the organisms
which compose them.
Approximate synonyms for synecology include Vegetation Science and Vegetation
Ecology.
Non-mutually exclusive approaches to synecology include:
a. Phytosociology, geobotany, plant community description and classification.
b. Paleoecology.
c. Plant geography, vegetation geography.
d. Community dynamics (emphasized in this course)
3. Ecosystem ecology
An ecosystem includes "not only the organism-complex, but the whole complex of
physical factors forming what we call the environment." (A. Tansley 1935).
"An ecosystem is a functional system that includes an assemblage of interacting
organisms and their environment, which acts on them and on which they act." (R. Whittaker
1962).
Emphasis in an ecosystem approach is on exchange of matter and energy between the
physical environment and the living environment.
FOREST DYNAMICS or FOREST STAND DYNAMICS (the emphasis of this course)
"Forest stand dynamics is the study of changes in forest stand structure with time,
including stand behavior during and after disturbances" (Oliver and Larson 1990).
A stand is a spatially continuous group of trees and associated plants having a similar
structure and growing under similar environmental conditions. Can be any size but must be
relatively homogeneous.
Stand structure is the spatial arrangement of and size differentiation (or age
differentiation) of plants (but especially trees) within a stand. Can be characterized by tree
diameters, ages, heights, crown densities, stem volumes, understory vegetation, etc.
"Disturbances are any relatively discrete events that disrupt the stand structure and/or
change resource availability." (Pickett and White 1985). Includes both natural and
anthropogenic disturbance, and abiotic and biotic disturbance.
Study of forest dynamics includes both:
a. succession (directional change in species composition), and
b. regeneration dynamics or maintenance dynamics (e.g. changes in population
structures occur even though there is no significant change in the species composition).