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During the summer of 1987, a series of discussions I was held at
the International Institute for Applied Systems Analysis (nASA) in
Laxenburg, Austria, to plan a study of global vegetation change.
The work was aimed at promoting the Interna tional
Geosphere-Biosphere Programme (IGBP), sponsored by the
International Council of Scientific Unions (lCSU), of which nASA is
a member. Our study was designed to provide initial guidance in the
choice of approaches, data sets and objectives for constructing
global models of the terrestrial biosphere. We hoped to provide
substantive and concrete assistance in formulating the working
plans of IGBP by involving program planners in the development and
application of models which were assembled from available data sets
and modeling ap proaches. Recent acceptance of the "nASA model" as
the starting point for endeavors of the Global Change and
Terrestrial Ecosystems Core Project of the IGBP suggests we were
successful in that aim. The objective was implemented by our
initiation of a mathematical model of global vegetation, including
agriculture, as defined by the forces which control and change
vegetation. The model was to illustrate the geographical
consequences to vegetation structure and functioning of changing
climate and land use, based on plant responses to environmental
variables. The completed model was also expected to be useful for
examining international environmental policy responses to global
change, as well as for studying the validity of IIASA's
experimental approaches to environmental policy development.
During the summer of 1987, a series of discussions I was held at
the International Institute for Applied Systems Analysis (nASA) in
Laxenburg, Austria, to plan a study of global vegetation change.
The work was aimed at promoting the Interna tional
Geosphere-Biosphere Programme (IGBP), sponsored by the
International Council of Scientific Unions (lCSU), of which nASA is
a member. Our study was designed to provide initial guidance in the
choice of approaches, data sets and objectives for constructing
global models of the terrestrial biosphere. We hoped to provide
substantive and concrete assistance in formulating the working
plans of IGBP by involving program planners in the development and
application of models which were assembled from available data sets
and modeling ap proaches. Recent acceptance of the "nASA model" as
the starting point for endeavors of the Global Change and
Terrestrial Ecosystems Core Project of the IGBP suggests we were
successful in that aim. The objective was implemented by our
initiation of a mathematical model of global vegetation, including
agriculture, as defined by the forces which control and change
vegetation. The model was to illustrate the geographical
consequences to vegetation structure and functioning of changing
climate and land use, based on plant responses to environmental
variables. The completed model was also expected to be useful for
examining international environmental policy responses to global
change, as well as for studying the validity of IIASA's
experimental approaches to environmental policy development.
The response of forests to global climate change is one of the most
hotly contested issues in the greenhouse effect debate. Much effort
is being devoted to the construction of models which describe the
function of the forests and their rate of change. There are a
wealth of techniques available to project large-scale vegetation
patterns, all based on different underlying models that contain
fundamental biological and ecological mechanisms. Vegetation
Dynamics and Global Change will introduce both students and
professionals to the sophisticated mathematical and computational
tools used to predict the rate of change in the world's forests. It
emphasizes the importance of scale in global studies. Leaders in
the field of vegetation modeling cover physiological phenomena
typically measured at small time and space scales; the stand
dynamics of forests; large-scale models of forest dynamics; the
reconstruction of forest vegetation of past climates as a way to
understand current global changes; and the role of forests in the
global carbon cycle. Several themes run through the book, including
the need to understand how processes important at one time and
space scale can be conceptualized at larger scales; the need to
optimize the conceptual benefits of representing processes in
detail and the attendant difficulties of estimating parameters and
designing tests for elaborate models; and the need to identify the
most appropriate system variables.
The boreal forests of the world, geographically situated to the
south of the Arctic and generally north of latitude 50 degrees, are
considered to be one of the earth's most significant terrestrial
ecosystems in terms of their potential for interaction with other
global scale systems, such as climate and anthropologenic activity.
This book, developed by an international panel of ecologists,
provides a synthesis of the important patterns and processes which
occur in boreal forests and reviews the principal mechanisms which
control the forests' pattern in space and time. The effects of cold
temperatures, soil ice, insects, plant competition, wildfires and
climatic change on the boreal forests are discussed as a basis for
the development of the first global scale computer model of the
dynamical change of a biome, able to project the change of the
boreal forest over timescales of decades to millennia, and over the
global extent of this forest.
Predicting how terrestrial ecosystems might respond in the future to large-scale human-generated changes is a major challenge for ecologists. In Terrestrial Ecosystems in Changing Environments, Herman H. Shugart describes the fundamental ecological concepts, theoretical developments, and quantitative analyses involved in understanding the responses of natural systems to change. The key ecological concepts described include the ecosystem paradigm, niche theory, vegetation/climate relationships, landscape ecology and ecological modeling. A variety of ecological models are presented, and their applications in predicting responses to change are considered. The challenge of producing ecological models capable of predicting long-term and large-area ecosystem dynamics is reviewed and several examples are provided. Finally, some of the exciting new findings regarding terrestrial landscapes and their feedback with their climatic setting are discussed in the context of human land use and global change.
To the human eye, a forest is a slowly changing ecosystem that,
superficially, looks alike from one year to the next. This seeming
quiet though is a balance between the tremendous progenerative
potential of trees and an equally tremendous mortality rate. The
intrinsic nature of the trees that comprise a forest make it all
but impossible to collect complete data sets on the dynamics of
natural forests and our understanding of the long-term dynamics of
forests is based largely on scientific inference. Because of this
reliance on inference, mathematical models of forest dynamics offer
a valuable formalization of what we believe to be the important
mechanisms involved in forest succession. Originally published in
1984, A Theory of Forest Dynamics is intended for scientists and
graduate students in ecology and forestry. The book includes: a
review of ecologic succession; coverage of forest dynamics models
and detailed analysis of several models of forest succession.
Mathematic models of forest dynamics are inspected and evaluated.
The models are applied to ecologic problems on scales ranging from
small forest gaps to entire landscapes and over years to millennia.
"Almost twenty years after its first publication, this book
continues to be a highly valuable resource for forest ecologists,
whether they are engaged in dynamic modeling or not. It provides a
thorough, mathematically underpinned theory of forest succession
with a large array of application examples. I am thrilled that this
volume is available again." Dr. Harald Bugmann, Professor of
Mountain Forest Ecology, ETH Zurich, Switzerland "Since this book
was first published in 1984, it has been a seminal publication
describing the ecological processes controlling the dynamics of
forest ecosystems. The scientific relevance and importance of the
book have only increased over time. In particular, as climate
modelers now realize that terrestrial ecosystems are an important
feedback in the climate system they are including dynamic
vegetation models in their climate models. This allows vegetation
to change as climate changes, feeding back to affect climate. Hank
Shugart's book outlines the theory of forest dynamics needed to
successfully include dynamic vegetation within climate models." Dr.
Gordon Bonan, National Center for Atmospheric Research, Boulder,
Colorado "Hank Shugart's book A Theory of Forest Dynamics has
served as a "bible" in the field of forestry and ecology since its
original publication in 1984. It made the forest gap model known
world-wide, which led to the application of a large number of
forest gap models to almost all forest types and continents. It has
become a classic in forest science. Traditionally, forest science
was regarded as a statistical and experienced science because trees
could not be observed by a single person for an entire life span,
making it impossible to predict the consequences of forest
management, disturbances and environmental changes. The invention
of the forest gap model quickly changed that situation because
forest gap models can record, simulate and forecast the past,
present and future in an understandable scale so that long term
dynamics of forests may be understood based on a small group of
hypothesis related succession factors: birth, mortality, growth
under competition of light, water and space, parameterized by
simple forestry inventory in forestry and forest ecology. A Theory
of Forest Dynamics can be used both for research and teaching in
forest science. It was written for scientists interested in forest
science, but it has also been used as a textbook in computer
modeling and forest ecology." Yan Xiaodong, Deputy Director, START
TEA RRC, Institute of Atmospheric Physics, Chinese Academy of
Sciences, Beijing
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