ecosystems is represented by two integral indicators: the index of the forest stand
condition and the index of the structural diversity of forest biocoenosis.
The index of the stand condition H
1
(according to the E. R. Mozolevskaya
methodology [8] with changes and additions) reflects the viability of tree canopy
through the weighted average degree of crown foliation and gives a relative idea of
biological productivity and ecological assimilative ability of the study forest site.
=
=
k
i
i
i
f
Q
H
1
1
,
(1)
where Q
i
is a share of the total basal area of the i-th category of the condition; f
i
is coefficient of tree foliation of various categories of condition (1,0 – without signs of
weakening, 0,8 – slightly weakened (loss of foliation up to 25%), 0,6 – weakened (loss
of foliation up to 50%), 0,4 – strongly weakened (loss of foliation up to 75%); 0,2 –
dying (loss of foliation over 75%); 0 – dead standing trees /windbreakage of the current
year and past years).
One of the simplest and most practical approaches to estimating the weight of a
tree and its parts is to determine the dependences of the mass of the tree's parts on its
linear dimensions. Since linear dimensions are easier to determine than mass, then
allometric dependences are often used which are described by regression equations.
Fairly complete reviews of the literature on this problem was made by A. I. Utkin [9]
and V. A. Usoltsev [10]. Researchers use different parameters and types of functions,
however, according to D. G., Schepachenko [11], the approach to this problem has
changed little since 1944, when J. I. Kittredge [12] first used allometric function to
estimate the mass of leaves, using the equation:
,
3
,
1
b
fr
D
M
=
(2)
where M
fr
is the mass of phytomass fraction; D
1,3
is the average diameter of the
tree at a height of 1,3 m; a, b are coefficients [13].
The purpose of the work is to develop mathematical models of the growth of linear
dimensions (diameters and heights) of tree plants taking into account the effect of
photosynthesis, which will allow creating effective methods for determining the
components of CPE condition index.
The patterns of growth, dynamics and productivity of forest plantations are
represented using yield tables (YT) containing the age dynamics of the basic
mensurational indexes of the stands on the basis of accepted classification units, such
as site classes or types of forests and the results of studies on growth processes in
forests.
The most important part of many growth models of plants is their interaction with
light. The way of such interaction determines the density of the luminous flux that falls
on the surface of the plant, and this, in turn, through photosynthesis, can greatly affect
the rate and character of growth.
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