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Cover image for Contagious distributions in even aged forest stands : dynamics of spatial pattern and stand structure / by Fiona C. Hamilton.
Contagious distributions in even aged forest stands : dynamics of spatial pattern and stand structure / by Fiona C. Hamilton.
Title:
Contagious distributions in even aged forest stands : dynamics of spatial pattern and stand structure / by Fiona C. Hamilton.
Author:
Hamilton, Fiona C.
Personal Author:
Publication Information:
1984.
Physical Description:
[9], 61 leaves, bound : illustrations, maps ; 29 cm.
General Note:
Typescript (photocopy).
Abstract:
Six stands of Eucalyptus regnans and E. delegatensis with significantly contagious or clumped spatial patterns, were observed between either ages 4 and 12 or ages 30 and 41 years. The effects of aggregation on the development of these stands are described. The prediction of growth and mortality responses of individual trees is demonstrated in these stands where average stand density measures are not good indicators of the competitive conditions which individual trees face. Results show that clumping intensifies competition, producing a high proportion of suppressed stems and substantial mortality even in regions of low average density. Average tree size is reduced. The bimodal diameter distribution illustrates the distinct separation of the suppressed class from the dominants and codominants. Individual tree growth differs significantly between crown classes. Basal area growth of the suppressed stems which survive averages near zero. In all crown classes variables which reflect competitive conditions such as distance to the nearest neighbouring tree and the basal area in larger trees are more successful predictors of individual tree growth than average stand density variables. Mortality is largely confined to the suppressed class and within any stand can be predicted by tree size and local density variables. The concentration of mortality in the densest parts of the stands is changing the spatial pattern, so that the degree of contagion is decreasing through time. A high degree of contagion results in increased variability of conditions within a stand and high local densities around some trees. The associated intensification in competition in these areas of the stand produces responses which are similar to those we would expect under an increase in general density.