Relationship of the productivity of forest den-drocenoses with the geomorphological profile of soils and their influence on the ecology

It is well known that there is a relationship between the productivity of forest phytocenoses and soil fertility, which is largely determined by the terrain and soil geomorphology. An important element of assessing the productivity of forests is the substantiation of the methodology for modeling the age dynamics of the growth of forest stands, depending on soil and ground conditions. The solution of this methodological problem is possible only if there is data on forest objects, represented by permanent sample plots and data from a detailed soil survey.


Introduction
In our case, the object of the study was the Lesnaya Opytnaya Dacha (Forest experimental site) (FES), which is a scientific station and an educational training ground with an area of 232.3 hectares on the territory of Moscow. In the forest area, long-term periodic (after 10-15 years) observations of the growth, structure and productivity of forest stands are carried out, as well as their impact on the environment is assessed. The organization of the FES territory is associated with the name of the famous scientist-forester Count A.R. Vargas de Bedemar. which in 1863 carried out the first forest inventory [1 ]. The forest area was divided into 14 quarters with a description of plantings in them and the establishment of permanent sample plots. Later, scientists-foresters of the Petrovskaya and Timiryazevskaya academies V.T. Sobichevsky, M.K. Tursky, N.S. Nesterov, V.P. Timofeev, G.R. Eitingen, A.N. Polyakov and others continued to observe naturally forming forest stands and forest cultures of various mixing and density. In total, 156 test plots were laid in the plantings, on which regular observations have been carried out for more than 150 years. The forest growing conditions of FES are represented by meso-hygrophilic (C3) and hygrophilic (C4) complex subors -relatively rich soils. However, the accepted classification only in the first approximation characterizes the soil-typological conditions found in the forest area.
G.N. Vysotsky is a contemporary and student of K.A. Timiryazev and V.V. Dokuchaeva developed the doctrine of forest-vegetation zoning, developed a diagram of natural zones demonstrating the relationship between the distribution of forest vegetation, depending on climatic, soil and hydrological conditions. The scheme proposed by him has not lost its significance so far. He made a significant contribution to the study of the impact of forests on the environment, to the classification of types of water regime of soils and grounds [12].
Later N.V. Dylis, V. N. Sukachev [5 ] for the first time formulated the theory of the horizontal structure of forest biogeocenoses (BGC). Starting with the works of L.O. Karpachevsky [9,10] the idea gradually developed that the soil cover in forest biogeocenoses resembles a honeycomb (parcell) structure. A parcel represents forest areas isolated in space (along a conventional radius), formed by a specific edificator and dominants of the vegetation cover. Within the parcel, along the radius from the edificator, the influx of litter, accumulation of litter, consumption of water and nutrients change.
Yu.P. Demakov, A.V. Isaev [3] indicate that at present, a lot of factual field material has been accumulated, various kinds of measurements for systematization and data processing. This requires only the correct formulation of problems in identifying conformities (relationships), the use of system analysis with elements of mathematical statistics and modeling methods.
In modern economic conditions, large-scale field surveys are very problematic, therefore, the use of field material already accumulated by predecessors, both on soils and on the growth, productivity of forest phytocenoses, should be considered a good basis for successfully solving the problem posed in the study.
V.D. Zelikov [7] it is shown that the granulometric composition of soils and the thickness of the soil profile has an important role in the ontogeny of forest stands. Using statistically reliable data, the author has shown that forest stands with a predominance of pine reach the highest bonitet (I-I a ) in those cases when they grow on deep sandy loamy-sandy deposits, as well as loamy soils up to 120 cm thick. D.A. Danilov and V.P. Tsarenko [2], studying the influence of the granulometric composition of soils on the productivity of naturally formed stands of spruce and pine in the conditions of the Northwest region. They noted that on loamy and sandy loamy soils, the pine element of the forest shows greater productivity and better marketable qualities of wood than spruce. The authors conclude that with age in these soil conditions, pine mixed with spruce covers most of the ecological niche, which affects the overall productivity of forest stands.
O.V. Martynenko [11] provides information on the developed regression model of the productivity of pine forest stands of SCHUOLKh of the Moscow region. At the same time, it is indicated that information on bonitet classes, expressed by the average height of stands at 100 years of age, was taken as an independent variable. And as independent variables in the formation of the model, such variables as the level of groundwater, the content of humus in the root-accessible soil layer and the upper boundary of the appearance of signs of gleying in the mineral part of the profile are involved. At the same time, it is noted that bonitet is a dynamic indicator and not sufficiently reliable for long-term forecasting.
The presence of permanent sample plots of FES opens up great opportunities for conducting research that allows one to assess the role of various elements of dendrocenosis of artificial and natural origin on the soil-forming process and the structure of sod-podzolic soils. At the same time, the data of taxation indicators of forest stands on permanent sample plots make it possible to reveal the influence of soil characteristics on the dynamics of productivity of dendrocenosis elements [16].
The aim of the study was to develop a methodology for assessing the dynamics of growth by average height and productivity of closed stands located at different levels of geomorphological soil surfaces.
Study objectives: 1.Conduct modeling of age-related changes in the average height of the main forest elements based on data from permanent sample plots.
2.Reveal the relationship between the levels of productivity of forest stands located at different elevations of geomorphological surfaces.

Research methods
Experimental material is represented by a series of sample plots (Table 1), presented in different parts of the FES geomorphological profile (Fig. 1).   Sod-podzolic slightly sod medium-superdeep podzolic profilegley light loamy on moraine sand. PD Gl3
It should be noted that the generally accepted tool in forestry and forest inventory for assessing the productivity of plantations is the boniteration scales of Professor M.M. Orlov separately for seed and coppice stands, as well as the improved VNIILM quality class scale, which takes into account the growth energy of stands at average height for forest-forming species of slow, moderate and fast growth. Bonitet is mainly a classification characteristic of forest stands by productivity (stock) at the time of taxation. He only states the level of productivity, not linking it with the geomorphology and forest vegetation properties of soils [17,18].
By the decision of the silvicultural part of the work, it is envisaged to link the geomorphological surfaces of the Lesnaya Opytnaya Dacha with the productivity of forest phytocenoses. It is generally accepted to assess the productivity levels of forest stands either on a bonitet or on a forest typological basis according to the relationship between the average height of the forest stands with age [14]. Observing this condition for each of 38 permanent sample plots, we simulated the age-related change in the average height of the stand according to the growth function of Korsun-Bakman: In all cases, the smoothing of the empirical data of the sample plots is characterized by a very high closeness of the relationship, close to the functional one, with a coefficient of determination from 0.995 to 0.999.
Further, for each sample plot, using the indicated regression equations, the average height at 40, 70 and 100 years of age was determined. The obtained values of the average heights were included in the calculation of the numerical regression coefficients. Along with this, a matrix of binary variables was compiled, encoding conventionally given decades with a gradation of 30 years ( Table 2) in accordance with the guidelines set out in the monograph [15 ]. About σ -random error of the equation,%. The presented parameters of the model (1) indicate the presence of a close relationship between the average height of the forest stands with the independent variables included in the equation, covering 77% of the variance of the dependent variable. The statistical significance of the parameters of the equation, the absence of a systematic error (Δ = 0.81%) and the presence of a random error not exceeding ± 13% indicate a sufficiently high accuracy of the model, which takes into account only one physical indicator -the height above sea level.
The degree of correspondence of the theoretical values of heights to the actual ones is clearly shown in Figure 2. The location of the theoretical values of the height along the diagonal of the square of the adequacy assessment confirms the conclusion made.
R 2 =1,0; t>t05=1,96 The age-related change in the average heights of forest stands growing at different heights of the geomorphological profile of the FES is shown in Figure 3 A graphical interpretation of the new model is shown in Figure 4. The theoretically obtained tabular data, as well as the three-dimensional graph of changes in the average heights of forest stands in terms of age and height above sea level, clearly indicate a high degree of mutual influence of the variables included in the model. The regression surface, supplemented by arrows indicating the value of the systematic elevation excess, allows judging the level of excess of the average heights of forest stands at different heights above sea level from the lowest (Н УМ = 160 m) to the highest (Н УМ = 175 m). Thus, the maximum excess is observed in mature stands and is 15 m, which corresponds to four bonitet classes.