Home – Home – Jornals – Siberian Journal of Forest Science 2020 number 5

We present the results of an analysis of forest stand dynamics on a permanent trial plot in the Sikhote-Alin biosphere reserve (Primorsky Krai). The materials of revisions for the period 1958-2019 were used, where the plot was established on young growth forest, which emerged after a strong wildfire in the 1920s succeeding in the place of which a highly productive pine trees. The last inventory (2019) reflects the state of the plantation after strong windfall due to the typhoon Lyonrock in 2016: the growing stock of the stand decreased from 254 to 180 m³ · ha^-1. Currently the total average (stock) increment is 4.7- 8.4 m³ · ha^-1 · year^-1, losses due to windfall varied between 1.4-3.0 m³ · ha^-1 · year^-1 and were 12.0 m³ · ha^-1 · year^-1 for the last observation period. Sufficient seedlings for a further recovery of the main species (Korean pine Pinus koraiensis Siebold & Zucc.) are present only at sites without disturbance by windfall (up to five thousand plants ha^-1). Using regional allometric equations, the above-ground biomass of trees and stands was determined for each inventory period, which made it possible to estimate the net growth of the biomass at 1.31 t C · ha^-1 · year^-1, which is more than two times higher than the average specific carbon stock in the biomass of the forests of Terney forest district estimated by the ROBUL system. Windfall decreased the biomass stock in the forest stand from 89 to 60 t C · ha^-1. The stand developed following a long-term regeneration scenario, but further stand dynamics are unpredictable due to the instability of the rest of the stand.

In studies of tree fire damages, attention is usually paid to growth and development of wood (xylem). But for tree vitality a very important role belongs to the tissues outside the cambium - phloem (inner bark). The object of this work was to continue the study of anatomical features and chemical composition of inner bark of Scots pine Рinus sylvestris L. stems with different fire scars after prescribed fires of different intensity. The fire experiments were carried out in pine stands in Lower Angara river region of the Angara provenance, Krasnoyarsk Krai, Central Siberia. Anatomic analyses of stem cores of experimental and control trees were carried out by the methods of light microscopy and histochemistry. It was shown that eight years after the low-intensity and 13 years after the medium- and high-intensity fires, the thickness of inner bark increased in all the studied trees, as well as in the control. Moreover, a decrease in the number of annual phloem layers between the cambium and periderm was noted. The number of cells in the radial row of the conducting phloem after a low-intensity fire was almost the same in inner bark of trees damaged by fire and not damaged (control), after a medium-intensity fire, it decreased with an increase of fire scars square, after a high-intensity fire a tendency to increase in trees with severe fire damage was noted. The content of axial parenchyma was found to increase with increase of stem fire damage in trees after a low-intensity fire and decreased after fires of medium and high intensity. There was a tendency to an increase in the frequency of phloem rays in tree trunks with an increase of stem fire damage after a low-intensity fire; after medium-high and high-intensity fires any trends could not be identified. Distribution and amount of starch in the ray and axial parenchyma in the inner bark of all model trees was found to be almost the same. A tendency to increase the accumulation of callose in non-conductive phloem with an increase in the intensity of fire impact to the trunks was revealed. It is confirmed that the annual phloem layers formed after the fire do not contain lignin.

Carbon dioxide gas exchange and the pigment content of the photosynthetic apparatus of the Siberian stone pine Pinus sibirica Du Tour ecotypes vegetative scion from the West Siberian latitudinal transect grown on the geographical grafting plantation in the south of the Tomsk Region were studied. The latitudinal transect was represented by three ecotypes: Tomsk, the southern border of the range; Strezhevoy, middle taiga; Urengoy, northern border of the range. The age of the grafted trees was 20 years. It was shown that the photosynthesis intensity did not differ between ecotypes significantly, respiratory activity increased significantly from south to north, and the differences were 79 % between marginal ecotypes. The results of the experiment revealed that the respiration / photosynthesis ratio was twice as high in northern than in southern ecotype, which indicates a lower plant productivity of the northern ecotype. The results of measuring stomatal conductance and the intercellular CO₂ concentration showed that these values did not differ between ecotypes significantly. Research has revealed the tendency towards the decrease of green pigment contents in the middle taiga ecotype and the significant decrease those in the northern ecotype. The Chl a / b ratio increased from south to north from 2.7 to 3.2. On the contrary, the Chl/Car ratio decreased between marginal ecotypes from 6.2 to 5.7 due to the reduce of green pigment contents in the northern ecotype. The obtained data indicate the photosynthetic acclimation when ecotypes were moved to the warmer climate. The photosynthetic pigment synthesis and respiratory activity are largely regulated by hereditary factors (the ecotype origin).

The annual tree increment is one of the integral indicators of abiotic and biotic processes occurring in the forest ecosystem. The use of logistic regression models based on annual tree-ring growth data is a promising approach to studying tree mortality. The diversity of logistic variables in scientific research is a result of various choices of statistics (average, median, growth trend, etc.) and their score in the time-window for the past N (5, 10, ..., 40) years. We propose a new scheme for the formation of logistic variables that involves fixing the statistics for calculating the average and choosing two non-intersecting time-windows based on measurements of the annual tree-rings growth. The choice of non-overlapping «windows» enables setting the ratio of the average growth of annual rings of trees between the windows for different periods of time. We examined the past 41 years of tree growth. Logistic regression models are constructed on a set of pairs of non-intersecting «windows» with a limit on the values of the sensitivity and specification of at least 1.6. The calculation of the percentage prediction if a tree is living or dying was done based on the contingency table in the logistic regression model. The logistic regression models were visualized using ROC curves. The models were compared on an expert scale based on the calculated area under the ROC curves. The obtained logistic regression model was verified by the bootstrap method. The calculations were carried out for the Siberian stone pine Pinus sibirica du Tour growing in the Baikal region (the Khamar-Daban Ridge) using the R programming language. The computed logistic regression model helped us predict live and dead trees in more than 80 % of cases.

Of great importance when conducting forestry operations and scientific research is the accuracy of determining the height of trees. The height of trees in a particular area is usually calculated using models, where it is a function of diameter at breast height. Among simple models, three-parameter models are the most flexible and allow for more detailed transmission of the dependence. The purpose of the work is to select the most adequate one from the set of three-parameter models based on the materials used to measure model trees in birch stands, which conveys the relationship between the height of trees and diameter at breast height. On the materials of 23 sample plots with the measurement of model trees laid in birch stands of the Forest Experimental District of the Timiryazev Agricultural Academy, parameters were determined for 11 three-parameter models selected from literary sources. Model parameters were calculated by minimizing the standard error. The quality of the models was evaluated by the following metrics: the square root of the standard error, the coefficient of determination, the Akaike information criterion, the Bayes information criterion. The obtained results confirmed the advisability of using in practice the Mitcherlich equation (also known as Drakin-Vuyevsky, Chapman-Richards), which among the three-parameter models shows the best quality. The results of data analysis show that, from a statistical point of view, the differences obtained in the quality of models are not significant at the 5 % level ( t -test). Mitcherlich’s equation can be used in practice when carrying out forestry and research work in birch stands growing in the central regions of the European part of Russia. The methodology of the study allows you to repeat the same work for tree species and forest conditions, for which information about the nature of the relationship of height with the diameter at breast height is incomplete or absent.

The article presents the results of studies of ecological peculiarities of distribution of forest vegetation of the Ukrainian Rastochye based on an analysis of the floristic composition of plant communities. The following methods were used: phytoindication of ecological regimes based on ecological scales of F. N. Tsyganov, data mining methods, multidimensional ordination of plant communities based on the Principle Component Analysis, Analysis of Variance, statistical processing of ecological parameters of forest vegetation ecotopes. The results of a phytoindicative assessment of the conditions of forest phytocoenosis habitats are presented, which representing 22 associations of the classes Vaccinio-Piceetea, Oxycocco-Sphagnetea, Alnetea glutinosae and Querco-Fagetea, in nine parameters: Tm - thermal regime, Kn - continentality of climate, Om - climate humidity, Cr - cryo-climate, Hd - soil humidity, Tr - salt content, Rc - soil acidity, Nt - mineral nitrogen content, Lc - light-shading mode in plant community. The main regularity of the formation of ecotopes of forest vegetation of Ukrainian Rastochye consists in such a structure of interconnections between environmental parameters. The phytocenological space of the forest vegetation of Ukrainian Rastochye can be simplified in the form of an octagon, in the corners of which the associations are 8 located. Multidimensional ordination of forest vegetation of the Ukrainian Rastochye is characterized by the location of rare phytocenoses on the periphery of the ecological and phytocenological space. Practical significance. Patterns of the formation of forest vegetation allow solved the dynamics of vegetation cover, the relationships between different types of vegetation and environmental forecasting.

The paper considers the problem associated with the creation of databases. The review of available global, traditional soil databases is given. It is noted that they are of great scientific and practical importance. The description of the developed relational database «Heat Soil Portraits» in Microsoft Access is presented, based on the positive concept of representative soil profiles. The database contains information about the structural organization and thermal properties of natural and technogenic soils in Central Siberia. To create the database, we used materials from a morphological description, photographing, and ground radiometric survey in the thermal range of soil profiles obtained by the authors during the expeditionary work. Radiometric survey of soils was carried out according to the author’s method using a portable thermal camera. The structure of the designed database, its content and attributes are developed. Currently, the database includes information on 20 soil profiles of the main soil types and technogenic surface formations that are common in Central Siberia. The procedure for replenishing the created database with new information is simple to perform. A feature of the proposed database is the presence of photographs and thermal portraits attached to the description of a particular soil profile, which display the temperature distribution and structural organization of the soil profile. For each soil profile, temperature gradients are calculated that characterize the specific thermophysical properties of organogenic and mineral horizons. The prospect of DB development is replenishment with the results of radiometric surveys carried out in different seasons of the year and in different conditions of soil formation. Thus, the materials contained in the database can be used to assess the temporal and spatial variability of soils as a result of exposure to natural and anthropogenic factors.