Trunk Volume Research Articles

Размерно-качественные характеристики круглых сортиментов, заготавливаемых с применением многооперационных лесных машин

It is necessary to carry out a statistical assessment of the harvested wood parameters in order to increase the yield of round timber and the overall productivity of logging operations while operating multi-operational forest machines. Modern forestry harvesters are equipped with a variety of CAN control sensors to monitor operation and have onboard software that can collect and store input data on various file types to ensure continuous correct operation. One of the main file types is STM (trunk files). These files are presented in two forms: some contain information for each individual tree trunk in different files, and others store all the data for all trunks in one. The second type of STM files is the most relevant when analyzing the operations carried out at the logging site. However, it is inconvenient to use STM files every time to get information, so there is a need to convert the initial data into a table for easy transfer and decision-making at risk and uncertainty. The article proposes a method for transferring such data to a CSV table using Python pandas, numpy, seaborn, matplotlib programming language libraries, which help to process large data arrays quickly and efficiently and display them graphically. The data obtained by two operators using a medium-class Ponsse Ergo 8W machine in the typical natural and production conditions of the Mondi Syktyvkar JSC (Komi Republic, middle taiga zone) were used for the transfer. The efficiency of the operators’ work was assessed. We obtained functions for determining the volume of a tree trunk on the basis of the reported data from the forest machines. The analysis of structured data on the operation of multi-operational forest machines helps to improve decision-making during subsequent felling of trees with the selection of species, which provides the largest volume of round timber output. Moreover, it is possible to adjust assortment tables (APT-matrices) for shortand medium-term planning of assortment harvesting volumes.

Stand density effects on tree growth and climatic response in Picea obovata Ledeb. plantations

Stand density critically affects the growth and productivity of trees in various forest ecosystems, and thus their ability to provide goods and services. However, a better understanding of tree growth and forest stand structure interrelationships are critically lacking, which hinders our ability to develop sustainable management plans for climate resilient forests growth and development. The present study was carried out on Siberian spruce (Picea obovata Ledeb.) in southern taiga of Central Siberia in experimental plantations created in 1982. The initial planting densities DENS0 at 18 plots ranged from 500 to 128000 trees ha−1. Further stand density dynamics due to self-thinning was defined mainly by tree age; log-linear regression models explained 80–99% of its variation. The average tree diameter demonstrated allometric negative dependence on stand density persistently for inventory surveys at ages of 20, 25, and 35 years, while tree height became significantly dependent on stand density only to age of 35 years. Tree-level productivity (trunk volume and basal area) was negatively affected by stand density, while stand productivity was positively linked with it. Mean tree-ring width and latewood width both decreased persistently with rising stand density, and their responses to temperature and precipitation shifted to earlier calendar dates, e.g., from June-July to May-June. At the same time, behavior of latewood ratio chronologies (their synchronicity and climatic response) divided all plots in two groups: sparse (planting density of 500–6000 trees ha−1) and dense stands (8000–128000 trees ha−1).Besides shift of positive response to precipitation from August to July, for trees in dense stands latewood ratio is negatively affected by winter snow.

Whole Body Vibrations during Fully Mechanised Logging

This paper seeks to answer the question of whether the magnitude of vibrations affecting the whole body of the harvester operator (WBV) that are generated by the harvester boom is affected by the size of the processed trunk volume, to specify closer, the magnitude of WBVs generated during forest logging, and to localise these WBVs in individual partial operations. For these purposes, the production process, i.e., forest logging, was divided into six partial operations (Searching; Felling; Processing; Unproductive time; Machine movement; Stationary position). WBVs were scanned in the respective partial operations according to standard ISO 2631-1:1997 and the European Directive 2002/44/EC, and then the values were mutually compared. Volumes of processed trunks were recorded, which were then assigned to the given WBV during the respective operations. Research results did not demonstrate a correlation between the size of the transmitted vibrations and the volumes of cut trunks in the partial work operations of Felling and Processing. Neither a difference was found between the individual partial operations with two exceptions: Searching and Felling/Processing and Unproductive time. The research further showed that the average WBV of three partial operations did not meet the daily limit of 0.50 m/s2 permitted by European Directive 2002/44/EC, within a range from 12.20% to 27.02%.

The results of the introduction of twisted pine (Pinus contorta) in Bolshoy Solovetsky Island

Abstract In the central part of the Bolshoy Solovetsky Island, in the same type of growing conditions, two plots were created in 1988: the first consisted of twisted pine (Pinus contorta Loud. var. latifolia S. Wats) crops and the second one was of Scots pine (Pinus sylvestris L.). The aim of the study was to establish the morphological parameters of the twisted pine and its growth in the conditions of the Bolshoy Solovetsky Island in comparison with the native species P. sylvestris L. Also, we aimed to identify the features of P. contorta var. latifolia and determine the possibility and necessity of further introduction of the species. The preservation of the twisted pine and scots pine cultures was determined. Accounting trees were selected (62 and 31 trees, respectively), in which morphometric indicators were measured. Wood samples (cores) were taken from them with an age drill to measure radial growth. The radial increment was measured using the MBS-9 microscope and the Lintab device. To measure the increase in height, six medium-sized model trees were cut down. According to the taxation indicators, the two types differed slightly and the differences were most often unreliable. The average height of the twisted pine trees was significantly higher compared to that of Scots pine. The thickness of the bark varied; on average, at the age of 18, it was 1.35 ± 0.038 mm for twisted pine and 1.86 ± 0.095 for Scots pine, that is, the native pine bark was 38% thicker. Typical for twisted pine were a significant number of pathologies noted in 22% of the studied trees. Twisted pine was distinguished by a stronger development of the assimilation apparatus: the number of branches of the first order, the number of branches in the whorl, the life span of needles. An increase in radius (the width of the annual ring) was observed at 14–15 years, and then with age, the value decreased in twisted pine and remained at a consistently high level in Scots pine. The width of the late zone of the annual ring was 12% in Scots pine and 14% in twisted pine; but at a young age, the late wood in twisted pine was very small. The increase in height of the twisted pine was on average less than that of Scots pine. The dependence of the trunk volume on the diameter was almost identical in both species.

HARVESTER PRODUCTIVITY AND COSTS IN CLEAR CUTTING Pinus taeda STANDS UNDER DIFFERENT MANAGEMENT REGIMES

The increased demand for several forest products makes it necessary to apply different management regimes in forest stands, which may influence the wood harvesting operations. This study aimed to evaluate the effect of average individual tree volumes obtained through different management regimes on harvester productivity and costs, thereby enabling to generate information for forest managers. The study was carried out in three Pinus taeda L. stands under clear cutting with different average individual tree volumes (AIV): I (0.367 m3); II (0.582 m3); and III (0.766 m3). Working cycle times, productivity per productive machine hour, energy yield and production costs were obtained by a time and motion study, in which the average values obtained were compared by the Tukey-Kramer test (α ≤ 0.05). The work elements of the harvester’s work cycles were affected by forest management regimes, mainly the movement and the processing, with significant statistical difference between stands, but no difference between total working cycle times. The management regime applied to forest stands influenced the spacing and whole trunk volume which consequently increased the average productivity of the machine from 36.8 to 74.1 m³ per productive machine hour in treatments I and III, respectively, and reduced production costs by 50%. The forest management regimes influenced the clear-cutting operation with harvester.

Variability and plus tree selection in Swietenia macrophylla, from Kerala, South India

Big leaf mahogany (Swietenia macrophylla, King) is a valuable Neotropic timber species. It is the first extensively traded timber species to be listed in Appendix II of the CITES in 2002. The tree was introduced to India in 1795 and Kerala in 1872. The present study aimed at selecting plus trees of Swietenia macrophylla and evaluating their genetic variability. Forty-five plus trees were selected from 593 candidate trees spread over fifteen locations in Kerala based on baseline regression of trunk volume to crown volume, followed by scoring for qualitative characters. The clean bole height, GBH, crown width, crown volume and wood density of CPTs ranged from 6 to 13.4 m, 0.75 to 2.00 m, 8 to 15 m, 7 to 16 m and 21 to 23 mm, respectively. The plus trees were grouped into five clusters based on their quantitative and qualitative characters. Clustering was independent of the geographical location indicating a lack of development of any land races in the species. Key words: Swietenia macrophylla, Mahogony, Plus tree selection, CPT, Genetic variability

Vascular plants– phyto-indicators of geoactive zones in mountains and plains

The research was conducted in the Perm Region. Geo-structural analysis, phyto-indication, and biolocationwere used. Prior to this, forest ecosystems were studied by classical methods, in which it was found that the combinedinfluence of the density of microcenosis and the tree genotype determines the size of trees by only 40 %. It follows that 60%of the factors that determine the size of trees in different phytocenotic and soil conditions remain unknown. Therefore,we then began to study small geoactive zones (MGA-zones) with the hypothesis that they are related to the “small ringstructures of loose deposits of the earth’s crust” by Yu. I. Fivensky. Favorable MGA zones with a size of 1.0-3.0 m are foundwith a frequency of 220-250 pcs./ha and the pine tree is preserved 39 times better, increases the trunk volume by 46 %,forms 200-year-old forests, and its large trees are their indicators. Networks of them can be used as an energy frameworkand, for example, in a forest nursery, their energy in the conditions of cold spring increased the germination of spruceseeds by 7 times. Apparently, the forest species evolved using the energies of these zones; in any case, all the tree species westudied significantly increased their longevity and size. It shows promising sites with structures of Yu. I. Fivensky, whererings of hellebore (Verátrum lobeliánum Bernh.), fern (Dryopteris filix mas L.), and the highest trees of Siberian spruce(Picea obovate Leded) were previously discovered for the first time.) and Siberian cedar pine (Pinus sibirica Du Tour).

Low Cost Automatic Reconstruction of Tree Structure by AdQSM with Terrestrial Close-Range Photogrammetry

The quantitative structure model (QSM) contains the branch geometry and attributes of the tree. AdQSM is a new, accurate, and detailed tree QSM. In this paper, an automatic modeling method based on AdQSM is developed, and a low-cost technical scheme of tree structure modeling is provided, so that AdQSM can be freely used by more people. First, we used two digital cameras to collect two-dimensional (2D) photos of trees and generated three-dimensional (3D) point clouds of plot and segmented individual tree from the plot point clouds. Then a new QSM-AdQSM was used to construct tree model from point clouds of 44 trees. Finally, to verify the effectiveness of our method, the diameter at breast height (DBH), tree height, and trunk volume were derived from the reconstructed tree model. These parameters extracted from AdQSM were compared with the reference values from forest inventory. For the DBH, the relative bias (rBias), root mean square error (RMSE), and coefficient of variation of root mean square error (rRMSE) were 4.26%, 1.93 cm, and 6.60%. For the tree height, the rBias, RMSE, and rRMSE were—10.86%, 1.67 m, and 12.34%. The determination coefficient (R2) of DBH and tree height estimated by AdQSM and the reference value were 0.94 and 0.86. We used the trunk volume calculated by the allometric equation as a reference value to test the accuracy of AdQSM. The trunk volume was estimated based on AdQSM, and its bias was 0.07066 m3, rBias was 18.73%, RMSE was 0.12369 m3, rRMSE was 32.78%. To better evaluate the accuracy of QSM’s reconstruction of the trunk volume, we compared AdQSM and TreeQSM in the same dataset. The bias of the trunk volume estimated based on TreeQSM was −0.05071 m3, and the rBias was −13.44%, RMSE was 0.13267 m3, rRMSE was 35.16%. At 95% confidence interval level, the concordance correlation coefficient (CCC = 0.77) of the agreement between the estimated tree trunk volume of AdQSM and the reference value was greater than that of TreeQSM (CCC = 0.60). The significance of this research is as follows: (1) The automatic modeling method based on AdQSM is developed, which expands the application scope of AdQSM; (2) provide low-cost photogrammetric point cloud as the input data of AdQSM; (3) explore the potential of AdQSM to reconstruct forest terrestrial photogrammetric point clouds.

How wind acclimation impacts Pinus pinaster growth in comparison to resource availability

Abstract Key message Anthropic and natural disturbances in Pine pinaster forests may induce changes in tree wind exposure and resource availability. The wind acclimation has consequences on P. pinaster growth comparable to resource acquisition after sudden changes in micro-environmental conditions. Context More disturbances occur within the forest, resulting in the creation of inter-tree space. This increases resource availability for the remaining trees but also their wind exposure. Trees have the ability to acclimate to these changes in their micro-environmental conditions by modifying their development. Increase in both resource availability and wind-induced deformations (strains) are known to promote tree radial growth but their relative importance has not been previously analysed in field conditions. Aims This paper aims to study the Pinus pinaster growth in response to a sudden change in wind loading in comparison to a rapid increase in resource availability. Methods An experiment was established in a 16-year-old P. pinaster to create different conditions of wind loading and resources by guying trees with wires and removing their neighbours. The increase in trunk volume below 4 m was monitored for 3 years by measuring the stem radial growth at three stem heights. Results Acclimation to wind has important consequences for stem growth, comparable to that of the effect of greater resource availability after an increase in inter-tree spacing. The increase in trunk volume below 4 m induced by wind and by having more resources were quantitatively close and were equivalent after 3 years of treatment, to the trunk volume increase during the year before experiment. The observed wind acclimation was interpreted in terms of tree mechanical reinforcement by calculating the gain in the stem flexural rigidity: mechanical strength gains of 13.8 and 20.3% of swaying trees were observed in comparison to guyed trees for both high and low resource levels, respectively. Our analysis suggests that the relative effects of wind loading or higher resource are not modified over time by seasonable growth modulation. Both the effects of the wind acclimation and the higher resource were found to be independent and are likely to be cumulative. Conclusion This study highlights the importance of considering wind acclimation in the regulation of growth in forests after a sudden change in environmental conditions.

Capital Return Rate and Carbon Storage on Forest Estates of Three Boreal Tree Species

In this study, the capital return rate and carbon storage on forest estates with three boreal tree species are discussed. A growth model is applied, along with verified yield models of sawlogs and veneer logs. Using the normal forest principle, thinning schedules and rotation ages maximizing the estate-level capital return rate are clarified. Regeneration expenses are amortized at the end of any rotation. Capitalizations are greater and rotations longer than in recent studies. The capital return rate is a weak function of initial stem count and rotation age but differs by tree species. The initial stem count strongly contributes to biomass stored in trees. Omission of thinnings increases carbon storage very effectively but requires financial compensation. The most promising way of increasing the capital return rate is the reduction of regeneration expenses. Thinnings are triggered by stand volumes of at least 200 m3/ha. The average commercial trunk volume of trees removed in thinnings always exceeds 200 L. Risk aversion theory proposes short rotations and low stem count in seedling planting unless carbon storage compensation exists. Even a small carbon storage compensation justifies increased seedling counts and extended rotations.

Influence of trunk forking on height and diameter growth in an even-aged stand of Nothofagus pumilio

ABSTRACT In many tree species, trunk forking plays a major role in crown construction, and stands out as an indicator of the architectural transition between juvenile and adult trees. We aimed to evaluate the effects of trunk forking on height and diameter growth of Nothofagus pumilio trees in an even-aged monospecific stand in northern Patagonia, Argentina. We used cataphyll scars and ring-width measurements to compared yearly increments in mean trunk length and diameter of trees with forked and unforked trunks. After approximately 50 years of growth, trees with a forked trunk had reached larger radial growth than unforked trees, but there was no difference in height between the two groups. The larger trunk volume of forked trees suggests that they may have a competitive advantage over unforked trees; trunk forking could therefore, influence dominance/suppression relationships. Our results suggest that morphogenetic processes associated with trunk forking influence the establishment of size hierarchies in dense stands of Nothofagus pumilio.

Diversity assessment and selection of candidate plus trees of Ailanthus triphysa (Dennst.) Alston in Kerala

Ailanthus triphysa [Dennst.] Alston is one of the most important and extensively used trees for making match splints in India. Despite its multiple uses, the genetic variability of the trees is little explored. The study attempted to determine the genetic diversity and select candidate plus trees from various parts of Kerala. Thirty candidate plus trees were selected based on baseline regression of trunk volume to crown volume combined with scoring for qualitative characters. The tree height, GBH, crown diameter and clean bole height of the plus trees ranged from 20 to 37 m, 0.69 to 2.11 m, 3.5 and 9.75 m and 7 to 24 m, respectively. The selected CPTs can be used for tree improvement and development of superior quality planting material.

Nutrient accumulation and nutritional efficiency in eucalyptus

Eucalyptus accumulates large amounts of nutrients in its biomass and, in order to maintain high productivities, high doses of fertilizers are applied, mainly potassium. Adequate fertilization management requires information on nutrient contents in the various plant organs. This study aimed to use the boundary-line (BL) method to determine curves of nutrient accumulation in eucalyptus shoots. For this, a database containing information on yield and nutrient contents in the various plant organs was used. Scatter plots relating nutrient content in the areal part to trunk volume were constructed. In these graphs, points of the upper and lower edges of the cloud of points were selected, BLs were established and equations to quantify nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) accumulation were obtained. Subsequently, the K content obtained in boundary plants was correlated with those of the other nutrients in the same plants. The relationship between nutrient content and trunk volume allowed establishing the maximum and minimum accumulations for the same volume produced. Plants with highest K accumulation had 4.6, 2.07 and 2.0 less accumulation of N, P and Mg, respectively, than those with lowest K accumulation, for the same trunk volume. At the end, it is concluded that plants with higher K accumulation showed reduction in the absorption of N, P and Mg and lower efficiency in the use of K, P, Ca and Mg.

Tree Shape Variability in a Mixed Oak Forest Using Terrestrial Laser Technology: Implications for Mating System Analysis

The accuracy of the description regarding tree architecture is crucial for data processing. LiDAR technology is an efficient solution for capturing the characteristics of individual trees. The aim of the present study was to analyze tree shape variability in a mixed oak forest consisting of four European white oak species: Quercus petraea, Q. frainetto, Q. pubescens, and Q. robur. Moreover, we tested for association between tree shape and individual heterozygosity and whether oak trees identified as pollen donors in a previous genetic study have a larger size in terms of crown and trunk characteristics than non-donors. The woody structure of a tree was defined by the quantitative structure model (QSM) providing information about topology (branching structure), geometry, and volume. For extracting the 3D point clouds a high-speed 3D scanner (FARO FocusS 70) was used. The crown variables were strongly correlated to each other, the branch volume being influenced by branch length, maximum branch order, and the number of branches but not influenced by diameter at breast height (DBH), trunk length, trunk volume, or tree height. There was no relationship between the individual heterozygosity based on nuclear microsatellite genetic markers and crown and trunk characteristics, respectively. Branch volume, total area, DBH, trunk volume, and the total volume of tree were significantly larger in pollen donors compared to non-donor Q. petraea trees. Thus, the mean branch volume was more than three times higher. Pollen donors had nearly two and half times larger total area in comparison to non-donor individuals. Our results suggest that a thorough characterization of tree phenotype using terrestrial laser scanning may contribute to a better understanding of mating system patterns in oak forests.

Transcriptome-based single-nucleotide polymorphism markers between Pinus brutia and Pinus halepensis and the analysis of their hybrids

Natural hybridization occurs in sites where Pinus halepensis Mill. and Pinus brutia Ten. overlap geographically. Studies have shown that these hybrids demonstrate vigorous growth. Currently, there is no efficient method for hybrid identification. In the present study, a transcriptome database that was established from P. halepensis and P. brutia provided 111,388 potential SNP markers for hybrid identification. We selected 295 SNPs that were verified in silico using the Integrative Genomics Viewer (IGV) program. Forty-three SNPs were confirmed in vitro using several methods, including CAPS, HRM, TaqMan, KASP, and direct sequencing. Seven SNPs that were used for genotyping P. brutia trees in three planted sites along the climatic gradient of Israel demonstrated hybrid incidences of 2.5, 6.3, and 9.4%. The trunk volume of the hybrids in these sites was 2.9, 2.4, and 1.2 times larger than that of their P. brutia neighboring trees. Differences among the sites in the hybrid vigorous growth extent might have resulted from several factors, including genetic source, stand age, thinning history, and site conditions. However, the overall vigorous growth of the hybrids that was more pronounced in the arid site highlights the potential of interspecific hybridization as a means for improving the drought resistance of forest trees. This work provides a reliable SNP database for the identification of P. brutia × P. halepensis hybrids for the potential utilization of these hybrids to confront changes in climate.

Analysis of Taper Functions for Larix olgensis Using Mixed Models and TLS

Terrestrial laser scanning (TLS) plays a significant role in forest resource investigation, forest parameter inversion and tree 3D model reconstruction. TLS can accurately, quickly and nondestructively obtain 3D structural information of standing trees. TLS data, rather than felled wood data, were used to construct a mixed model of the taper function based on the tree effect, and the TLS data extraction and model prediction effects were evaluated to derive the stem diameter and volume. TLS was applied to a total of 580 trees in the nine larch (Larix olgensis) forest plots, and another 30 were applied to a stem analysis in Mengjiagang. First, the diameter accuracies at different heights of the stem analysis were analyzed from the TLS data. Then, the stem analysis data and TLS data were used to establish the stem taper function and select the optimal basic model to determine a mixed model based on the tree effect. Six basic models were fitted, and the taper equation was comprehensively evaluated by various statistical metrics. Finally, the optimal mixed model of the plot was used to derive stem diameters and trunk volumes. The stem diameter accuracy obtained by TLS was >98%. The taper function fitting results of these data were approximately the same, and the optimal basic model was Kozak (2002)-II. For the tree effect, a6 and a9 were used as the mixed parameters, the mixed model showed the best fit, and the accuracy of the optimal mixed model reached 99.72%.The mixed model accuracy for predicting the tree diameter was between 74.22% and 97.68%, with a volume estimation accuracy of 96.38%. Relative height 70 (RH70) was the optimum height for extraction, and the fitting accuracy of the mixed model was higher than that of the basic model.

Musculature adaption in patients with lumbosacral transitional vertebrae: a matched-pair analysis of 46 patients

ObjectiveEven though lumbosacral transitional vertebrae (LSTV) are one of the most common congenital anomalies of the spine, their effect on surrounding soft tissues is not well-studied. We therefore aimed at analyzing the association between LSTV and changes in volume, mass, symmetry, and degeneration of lumbar and trunk muscles.Materials and methodsAbdomen–pelvis CT scans were analyzed in patients with LSTV and a matched control group. LSTV were classified according to the Castellvi classification. Muscles were segmented from the remaining soft tissue and their cross-sectional area and volume were examined at five defined levels. Threshold segmentation was used to differentiate between muscle fibers and fat tissue. Matched pairs were compared using Wilcoxon rank sum tests. For comparison of categorical data, chi-squared tests were performed and for associations between the degree of fusion and muscle size and degeneration, Spearman’s correlation coefficients were calculated. Inter- and intrarater reliabilities were evaluated by computing intraclass correlation coefficients.ResultsForty-six patients with LSTV and 46 controls were included. Muscle volume of the paraspinal and trunk muscles was significantly lower (707.0 cm3 vs. 809.7 cm3, p < 0.001) and fatty muscle changes were significantly increased in all but the caudal paravertebral muscles of LSTV patients (M. psoas p < 0.04, M. quadratus lumborum p < 0.001, paravertebral muscles p = 0.011, M. rectus abdominis p < 0.001, M. obliquus abdominis p < 0.001). Correlations between the degree of Castellvi classification and muscle volume were significant (p = 0.001).ConclusionLSTV are associated with a reduction in muscle volume and an increase in muscle degeneration of both lumbar and trunk muscles.

Orchard biomass residues: Chemical composition, biological activity and wood characterization of apricot tree (Prunus armeniaca L.)

AbstractRecent EU directives have encouraged member states to follow circular economy guidelines on waste reuse, especially for waste originating from wood agro‐forest biomass. Delineating the antioxidant and chemical activity of biomass is a starting point to find new ways to utilize such materials. Here, an 8‐year‐old apricot (Prunus armeniaca L.) tree stand located in southern Italy was evaluated. First, dendrometric parameters (total volume, diameter, and height of trunk below the branches) and physical‐mechanical properties (density, total, tangential and radial shrinkage, moisture content, and compression strength) of timber collected from five experimental plots was evaluated. Bark and wood from apricot pruning were then subjected to different extraction techniques, in vitro antioxidant assays, and gas chromatographic studies to determine their antioxidant activity and their phytochemical composition. Bark had the highest antioxidant activity compared to wood. Several antioxidant compounds (e.g., scopoletin and naringenin) were detected in the samples, explaining the measured antioxidant activity. In conclusion, this study demonstrates the potential of using apricot extracts in nutraceutical, cosmeceutical, and industrial fields. © 2021 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Оценка экологической пластичности и стабильности некоторых перспективных сортов тополей

When developing promising assortments of forest woody plants, it is important to take into account not only their growth and survival in some particular environment, but also their respond to change in growing conditions. In this regard, the purpose of this work is to evaluate the ecological plasticity and stability of some poplar varieties promising for the southeastern part of European Russia and Ukraine using the Eberhart and Russell method. The research was carried out on three testing sites: upland environment of the forest-steppe zone of the Voronezh region; floodplain environment of the dry steppe zone of the Volgograd region; and floodplain environment of the steppe zone of the Donetsk region. Five promising poplar varieties were identified and studied at each of the experimental sites. The indices of survival, growth in height and diameter, trunk volumes, and productivity by wood stocks and average increments are presented for each variety. Due to the average increments change with age, the ontogeny period from 21 to 30 years was chosen for the study, during which the average survival of poplars varies slightly. It was found that Regenerata, which is characterized by average plasticity and the lowest stability, was the most productive of the studied poplar varieties. It can perform high productivity only in the favorable environment. The poplar variety Pioneer demonstrated the least plasticity. Its productivity did not vary too much with change in growth conditions at average ecological stability. The highest plasticity at average ecological stability was observed in the Vernirubens variety. Average plasticity and stability were observed in poplar E.s.-38. The poplar variety Marilandica was also characterized by average plasticity, and high ecological stability. The research results allow using of the studied varieties more rational in different growing conditions, with regard to their environmental characteristics.

АСПЕКТЫ РАЗВИТИЯ СОСНЫ КРЫМСКОЙ ПРИ ИНТРОДУКЦИИ В УСЛОВИЯХ ЗЛАКОВЫХ И РАЗНОТРАВНО-ЗЛАКОВЫХ СТЕПЕЙ ПРИВОЛЖСКО-ДОНСКОГО ОКРУГА ЮЖНОЙ РУССКОЙ РАВНИНЫ

Crimean pine (Pinus nigra subsp.pallasiana Lamb.) better than other introduced tree species fits the environmental conditions of the studied region, as it is highly resistant to various pathologies and can be used to form complex (multilayered) uneven-aged multispecies stands. The significant age of the studied stands (110 and 118 years old) provides a good indication of this fact, as well as allows us to make a judgement on the features of growth and development of Crimean pine mixed with Scots pine. It should be noted that when Crimean pine is mixed with Scots pine its average trunk volume is 2.5 times higher than that of pure Crimean pine stands. Research suggests that the best plant growth pattern for the steppe conditions is when Crimean pine strips are grown between the Scots pine strips. The best plant spacing is 2x1 m and at least 2 Crimean pine rows should be spaced between Scots pine rows. Such a pattern best suits the В2 site type according to Pogrebnyak’s classification which corresponds to mesophytic mixed forests.