"Mike Sonntag" <MICHAEL@usys.informatik.uni-kassel.de> wrote:
> ... I am interested in every measure or method that might
> help to model competition and coexistence phenomena in mixed forests and
> to enhance the prediction capability for different climatic
> environments.
> EFT seems superficially to be a candidate (especially for a physicist
> like I am) but there remain some doubt or uncertainties:
....
> Any answers, and hints to more literature to this subject, would be
> greatly appreciated.
The paper by Pukkala, see below, and others by the same author deal
with Ecological Field Theory under that name. By the way, perhaps we
shouldn't encourage the use of pretentious TLAs (Three Letter
Acronyms) for not-so-new ideas?
The following paragraph includes some comments of mine related to the
subject. It is taken from:
Garcia, O. 1992. "What is a diameter distribution?" In: Minowa, M.
and Tsuyuki, S. (eds) Proceedings of the Symposium on Integrated
Forest Management Information Systems - An International Symposium.
Japan Society of Forest Planning Press.
" The influence of competition on the correlations and variances may
" vary depending on the predominant competition mechanisms. Competition
" may be "diffuse" (Schoonderwoerd and Mohren 1988), where it is
" exercised indirectly through sharing of substrate resources, or
" "sharp", arising from direct neighbour-to-neighbour interference.
" The diffuse competition concept is implicit in distance-independent
" models (in an extreme form, independent of distance), and in many
" distance-dependent competition indices (most clearly in Spurr (1962)
" and Pukkala (1988), for example). Sharp competition assumptions are
" most obvious in models that partition the growing space into polygons
" (Brown 1965, Gates et al 1979). With sharp competition, irregularity
" in the tree locations might obscure the influence of competition in
" the correlation functions, the correlations being then more related
" to neighbourhood relationships than to distance (Reed et al 1985).
" There is some evidence to suggest that underground competition for
" nutrients and water tends to be diffuse, while aboveground
" competition for light is "sharper" (Oliver and Larson 1990).
"
References:
AUTHOR = "G. S. Brown", TITLE = "Point density in stems per acre",
TYPE = "New Zealand Forestry Research Notes", INSTITUTION = "NZ Forest
Service", NUMBER = 38, YEAR = 1965
AUTHOR = "Timo Pukkala", TITLE = "Methods to Describe the Competition
Process in a Tree Stand", JOURNAL = "Scandinavian Journal of Forest
Research", VOLUME = 4, NUMBER = 2, PAGES = "187-202", YEAR = 1988
AUTHOR = "Stephen H. Spurr", TITLE = "A Measure of Point Density",
JOURNAL = "Forest Science", VOLUME = 8, PAGES = "85-95", YEAR = 1962
AUTHOR = "H. Schoonderwoerd and G. M. J. Mohren", TITLE =
"Autocorrelation and Competition in Even-aged Stands of {D}ouglas-fir
in the {N}etherlands", BOOKTITLE = "Forest Growth Modelling and
Prediction", EDITOR = "A. R. Ek and S. R. Shifley and T. E. Burke",
PUBLISHER = "USDA Forest Service, General Technical Report NC-120",
PAGES = "619-626", YEAR = 1988
AUTHOR = "David D. Reed and Harold E. Burkhart", TITLE = "Spatial
Autocorrelation of Individual Tree Characteristics in Loblolly Pine
Stands", JOURNAL = "Forest Science", VOLUME = 31, NUMBER = 3, PAGES =
"575-587", YEAR = 1985
AUTHOR = "Chadwick D. Oliver and Bruce C. Larson", TITLE = "Forest
Stand Dynamics", PUBLISHER = "McGraw-Hill", YEAR = 1990
AUTHOR = "D. J. Gates and A. J. O'Connor and M. Westcott", TITLE =
"Partitioning the union of disks in plant competition models",
JOURNAL = "Proceedings Royal Society London, A", VOLUME = 367, PAGES
= "59-79", YEAR = 1979
On the general topic of individual-tree models, also touched by Mike
in another posting, forgive me for quoting myself again. This is
from "The state-space approach in growth modelling", about to appear
in the Canadian Journal of Forest Research:
" Some potentially serious problems with individual-tree models have
" generally been ignored. Stands are not simple sets of trees; tree
" sizes show spatial structure. Micro-site similarities make
" neighboring trees be more alike than average, while competition has
" the opposite effect. The resulting spatial correlations cause size
" distributions to vary unpredictably with plot size (Garcia 1992). In
" particular, distributions obtained from plots will differ from those
" for whole stands, which are the ones required in the applications.
" Also, distance-dependent models have until now been based only on
" competition indices, ignoring micro-site effects. It seems that
" developing satisfactory individual-tree models might be more
" difficult than previously thought.
Oscar Garcia - ogarcia@valdivia.uca.uach.cl
Facultad de Ciencias Forestales, Universidad Austral de Chile,
Casilla 853, Valdivia, Chile. Fax +56(63)221227.
(Plse ignore return address in the header, use the one here)
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