Pine Radial Growth Research Articles

Dendroclimatic Response of Jack Pine (Pinus banksiana) Affected by Shoot Blight Caused by Diplodia pinea

The overall objective of our study was to examine the influence of climatic factors and tree-based competition on the radial growth of jack pine (Pinus banksiana) forests affected by the fungal pathogen, Diplodia pinea. Our study utilized dendroclimatic techniques to examine how past annual diameter growth can be influenced by the historical climate of the region. Twenty jack pine sites were sampled in Michigan within the Upper Peninsula (UP) and the Lower Peninsula (LP) region. Furthermore, two condition levels of forest health (D. pinea-affected vs. healthy reference stands) were considered between two levels of stand density (i.e., high vs. low density). The relationships between radial growth and climate identified in this study indicated that jack pine radial growth was typically affected by the climatic moisture index, whereas the response to temperature variables was weak to non-existent. In the Upper Peninsula region, crown damage likely sustained during harsh winters could have made jack pine stands prone to D. pinea by facilitating a point of entry for infection; furthermore, higher-density stands infected by D. pinea were influenced by moisture stress that occurred during the summer of the prior year. In the LP region, regardless of stand density, D. pinea was sensitive to moisture stress in the summer of the prior growing season; furthermore, negative relationships with precipitation in the spring may have improved spore dispersion in D. pinea-affected stands. Overall, our study provides improved understanding of the interactive role of climatic stress and forest pathogens on jack pine productivity.

The effects of climate change on Pinus tabulaeformis radial growth in the Xiaowutai Mountains, northern China

Clarifying the climate change effects on the radial growth of trees has implications for sustainable forest management, especially under global warming. To investigate tree growth responses to regional climate change of Xiaowutai Mountain, four Chinese pine (Pinus tabulaeformis) ring-width index chronologies were established at different elevations (1290–1600 m). Species growth trends were estimated using climate change projections derived from global climate models. The results show: (1) the four ring-width chronologies exhibited strong statistical characteristics, making them suitable for dendroclimatology studies. Radial growth-climate relationships were highly consistent, showing a negative correlation with previous September temperatures and current May–June temperatures, as well as a positively correlated with precipitation and Palmer Drought Severity Index during the corresponding period; and (2) climate change scenarios revealed that temperature will gradually increase on the Xiaowutai Mountain, and only a slight variation in precipitation is expected. Chinese pine radial growth may show a decline under future climate change.

Integrating Dendrochronological and LiDAR Data to Improve Management of Pinus canariensis Forests under Different Thinning and Climatic Scenarios

Thinning focused on achieving growth and diameter management objectives has typically led to stands with reduced climate sensitivity compared to unthinned stands. We integrated dendrochronological with Airborne Laser Scanner (LiDAR) data and growth models to assess the long-term impact of thinning intensity on Canary pine (Pinus canariensis) radial growth. In 1988, 18 permanent treatment units were established in 73-year-old Canary pine plantations and three thinning treatments were applied (C–control-unthinned; 0% basal area removal; MT–moderate thinning: 10% and 15% basal area removal, and HT–heavy thinning: 46% and 45% basal area removal on the windward and leeward slopes, respectively). Dendrochronological data were measured in 2022 and expressed as basal area increment (BAI). The impact of climate on growth was examined by fitting linear regression models considering two different Representative Concentration Pathway (RCP) climate scenarios, RCP 2.6 and RCP 4.5. Finally, LiDAR data were used for standing segmentation to evaluate changes in overall growth under different climatic scenarios. The LiDAR–stand attributes differed between aspects. The BAI of the most recent 20 years (BAI20) after thinning was significantly higher for the moderate and heavy treatments on the leeward plots (F = 47.31, p < 0.001). On the windward plots, BAI decreased after moderate thinning. Considerable thinning treatments resulted in stronger changes in growth when compared to RCP climatic scenarios. From a silviculture perspective, the mapping of canopy structure and growth response to thinning under different climatic scenarios provides managers with opportunities to conduct thinning strategies for forest adaptation. Combining dendrochronological and LiDAR data at a landscape scale substantially improves the value of the separate datasets as forecasted growth response maps allow improving thinning management plans.

Hardwoods influence effect of climate and intraspecific competition on growth of woodland longleaf pine trees

AbstractLongleaf pine woodlands of the North American Coastal Plain are proposed to be resilient to climate change impacts, but little is known about changes in limiting factors to longleaf pine growth as climate has changed in late 20th century and early 21st century. Moreover, the role that neighborhood trees play in the context of climate change remains largely unexplored. We used static and moving window tree ring and climatic analyses to measure the effects of climate on longleaf pine growth at a site in southwest Georgia, USA. We then performed maximum likelihood analysis to examine the influence of neighboring hardwoods on the response of longleaf pine growth to the joint effects of competition and climate. Analysis of climate data from local stations in southwest Georgia over six decades indicated that mean air temperature decreased until the late 20th century then began to rise, and that the variability of spring and summer precipitation has increased. Tree ring and climate analyses indicated longleaf pine radial growth is sensitive to precipitation and air temperature, and that the strength of correlation of longleaf pine growth to summer air temperature and summer precipitation increased since the 1950s. Likelihood models, which were applied over a shorter (23‐year) period and explicitly incorporated competition, did not support a link between summer temperature and growth but did indicate summer precipitation increased growth. Furthermore, basal area (BA) of neighboring hardwoods was correlated with greater pine growth per millimeter of precipitation. BA of neighboring longleaf pine negatively affected growth of conspecific trees; the presence of hardwoods increased the competitive effect when BA of neighboring pine trees was low (<10 m2 ha−1) but decreased the competitive effect when BA of neighboring pine trees was high (≥10 m2 ha−1). These results suggest that retention or recruitment of hardwood trees when restoring longleaf pine woodlands may contribute to increased ability to withstand dry summers and may help to allay concerns of managers that retention of hardwoods will unduly affect growth of residual mature longleaf pines.

Is there Chornobyl nuclear accident signature in Scots pine radial growth and its climate sensitivity?

The extensive radioactive fallout resulting from the 1986 Chornobyl accident caused tree death near the nuclear power plant and perturbed trees communities throughout the whole Chornobyl exclusion zone. Thirty years into the post-accident period, the radiation continues to exert its fatal effects on the surviving trees. However, to what extent the continuous multi-decadal radiation exposure has affected the radial tree growth and its sensitivity to climate variation remains unascertained. In this comparative study, we measure the Scots pine radial growth and quantify its response to climate at two sites along the western track of the nuclear fallout that received significantly different doses of radiation in 1986. The common features of the two sites allow us to disentangle and intercompare the effects of sub-lethal and moderate radiation doses on the pine's growth and climatic sensitivity. We extend the response function analysis by making the first use of the Full-Duration at Half-Maximum FDHM method in dendrochronology and apply the double-moving window approach to detect the main patterns of the growth-to-climate relationships and their temporal evolution. The stand exposed to sub-lethal radiation shows a significant radial growth reduction in 1986 with a deflection period of one year. The stand exposed to moderate radiation, in contrast, demonstrates no significant decrease in growth either in 1986 or in the following years. Beyond the radiation effects, the moving response function and FDHM enabled us to detect several mutual patterns in the growth-to-climate relationships, which are seemingly unrelated to the nuclear accident. To advance our predictive understanding of the response of forest ecosystems to a massive radioactive contamination, future studies should include quantitative wood anatomy techniques.

Response of Radial Growth of Mongolian Pine to Climate Factors in Mu Us Sandy Land, Inner Mongolia

The Mu Us sandy land is located on the northwestern edge of the East Asian monsoon region in China, and its environment is fragile and sensitive to climate change. To explore the response of the radial growth of Mongolian pine (Pinus sylvestris var. mongolica), the main afforestation tree species in this area, to climate change, a traditional method of tree-ring climatology was adopted to analyze the correlation of radial growth to climatic factors in the region from 1959 to 2019 based on annual ring widths of Mongolian pine. The results showed that water and heat conditions in May of the current year were the main climatic factors restricting the growth of this tree species in the Mu Us sandy land, mainly manifested as a negative correlation with the average temperature and maximum temperature in May of the current year, while a positive correlation with precipitation in this month. In addition, the average temperature and minimum temperature in March of the current year are also restricted to tree growth. Mongolian pine is one of the excellent tree species suitable for desertification control and afforestation in the Mu Us sandy land. Under the background of the changing climate, becoming warmer and drier, the effect of drought stress on the radial growth of Mongolian pine will become more and more prominent. If the temperature continues to increase in the future, the radial growth and carbon sequestration of Mongolian pine in Mu Us sandy land will be severely affected.

Радиальный рост сосны обыкновенной в условиях северной тайги

The research aims at assessing the influence of daytime and nighttime meteorological parameters (air temperature, dew point, relative air humidity, wind velocity and amount of precipitation) on the pine radial growth in the northern taiga subzone in blueberry, lingonberry and bush-sphagnum forest types. The study was carried out in the Arkhangelsk region near the Pinega settlement (northern taiga subzone). Sample plots were laid out in areas with different forest types specific for this territory. A total of 63 core samples were taken from 7 of the most representative sites. Meteorological parameters for 2008–2015 were collected by a digital weather station WMR918 H (Huger GmbH, Germany) located in the research area and operating in the monitoring mode. In blueberry pine forest, we have detected a high correlation of radial growth with air temperature and dew point in July (0.80–0.88), and even higher correlation with the night values of these parameters (0.90). Both direct and inverse correlations were found with wind velocities in May, June, and September: from 0.77 to 0.78 and from –0.84 to –0.79. An inverse correlation was observed in one of the sample plots with precipitation of May and June. Dependencies similar to the blueberry pine forest have been found in the lingonberry pine forest. A correlation with relative air humidity was found in the shrub-sphagnum forest type. Direct and inverse correlations of radial growth with wind velocity indicate its different influence on physiological processes in the leaf blade by cooling it and enhancing transpiration. Significant variability in the correlation in the blueberry forest type is probably caused by differences in the inventory parameters of the studied stands, and may also be a feature of blueberry pine forests. Generally, pine in the blueberry, lingonberry and shrub-sphagnum forest types has a similar response to the variability of meteorological factors, the main of which is the air temperature regime. Acknowledgments: The research was carried out within the framework of the state assignment No. 122011300380-5 of the N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences. For citation: Neverov N.A., Chistova Z.B., Mineev A.L. Radial Growth of Scots Pine in the Northern Taiga. Lesnoy Zhurnal = Russian Forestry Journal, 2022, no. 6, pp. 193–205. (In Russ.). https://doi.org/10.37482/0536-1036-2022-6-193-205

Radial growth of Scots pine in urban and rural populations of Ekaterinburg megalopolis

Eleven stands of Scots pine (Pinus sylvestris L.) from the city of Ekaterinburg and its surroundings were sampled and analyzed using dendrochronological methods to detect the effects of climate, biotic and anthropogenic factors on the annual growth of trees. Tree-ring chronologies were developed for six sites within the city and for five control sites. All chronologies were highly and positively correlated before the 1940s. However, after this period, there was a significant decrease in the correlation among chronologies from urban and rural sites. Divergence lasted about 20 years. This firstly has an anthropogenic cause, mainly due to the evacuation in 1941 of more than 60 industrial factories to Sverdlovsk (now Ekaterinburg), which generated a significant increase in air pollution. Environmental pollution seems to negatively affect tree growth. In the early 1950s, trees in the region also suffered from severe droughts. The results of climate and historical data analysis suggest that the trees on urban sites were weakened by both climate and air pollution factors, which led to a massive nun moth (Lymantria monacha L.) infestation of trees. Defoliation led to a drastic reduction in tree-ring width and, in some cases, to the complete loss of annual rings. The recovery period lasted 10–15 years on average. Rural populations were much less affected by the insect outbreak. After urban populations of pine recovered in the 1960s, radial growth of urban and rural populations became synchronized again.

Regional Features of the Radial Growth of Scots Pine under Climatic Conditions of the Forest-Steppe and Steppe Zones of Eastern Transbaikalia According to Multiparameter Tree-Ring Chronologies

Regional Features of the Radial Growth of Scots Pine under Climatic Conditions of the Forest-Steppe and Steppe Zones of Eastern Transbaikalia According to Multiparameter Tree-Ring Chronologies

Clumped or regular? the role of thinning pattern on pine growth and soil water content in dense Aleppo pine post-fire stands

The development of silvicultural practices that seek to promote structural heterogeneity is increasingly demanded. This work investigates the effect of thinning spatial pattern on the response to pre-commercial thinning of dense Aleppo pine post-fire stands. On three replicated experimental sites in SE Spain, we applied the following treatments: 600 trees/ha, regular thinning pattern (600R), with residual trees evenly spaced; 600 trees/ha, aggregated thinning pattern (600A), with residual pines arranged in clumps of ∽25 trees with a local within-clump density of 2500 trees/ha; and control treatment, with no thinning applied (> 20,000 trees/ha). We assessed treatment effects on pine growth, size-growth relationships, soil water content, and understory vegetation over the first three years after thinning application. Both regular and aggregated thinning pattern similarly increased pine radial growth. In general, dbh growth rates in response to thinning were faster for smaller trees than for larger trees. The growth rate of pine height was higher for 600R and control than for 600A, indicating a positive effect on height of both low and very high pine densities. We found a near-term positive effect of aggregated pattern on water availability at the stand level, mostly resulting from enhanced soil water content in the canopy gaps. For both thinning patterns, the recovery of understory vegetation was dominated by resprouter species. This study highlights the potential of aggregated thinning patterns to enhance the complexity and heterogeneity of the pine stands without compromising pine growth, which could be of great use to managing pine forests in Mediterranean areas.

Radial growth of Scots pine and Norway spruce stands as an indicator of soil and environmental conditions

The study presents an analysis of radial growth of Scots pine and Norway spruce trees growing on drained soils formed on varved clays at the sample sites of the Lisino Experimental Forestry (Lisino). Based on dendrochronological studies in Lisino, it has been found that the radial growth of Scots pine and Norway spruce is a sensitive indicator of changes in the soil water regime, climate, and phytocenotic relationships. On the basis of the character of tree-ring width growth, the growth charts allowed distinguishing zones with close to average growth values, as well as with increased and decreased values of radial growth. The cyclical pattern of tree ring width is well expressed in the successive change of zones. The availability of dendrochronological research materials with precise spatial and temporal reference makes it possible to organize monitoring of radial growth of trees as an indicator of changes in climate and habitat conditions.

Critical temperatures controlling the phenology and radial growth of Pinus sylvestris var. Mongolica on the southern margin of a cold temperate coniferous forest

Temperature plays a key role in phenology and growth of dominant tree species and hence in the structure and function of coniferous forests in cold temperate zones. We used a dendrochronological method to determine the critical temperatures of Pinus sylvestris var. mongolica (Mongolian pine) radial growth and the xylem growing season. Results showed that Mongolian pine radial growth is sensitive to daily mean temperatures of 4.0–5.5 °C in early spring, 14.0 °C in summer and 2.0–2.5 °C in autumn. A temperature of 4 °C might be the initial temperature required for sap flow, photosynthesis and tree germination in this area in early spring, and 5.5 °C is the most critical temperature for earlywood onset growth. The advance and extension of temperature 14.0 °C in summer can exacerbate water stress for trees and inhibit earlywood growth under the condition of insufficient precipitation. In autumn, 2.0–2.5 °C may be the minimum temperature for the xylem growth. These critical temperatures are important in predicting the changes in the phenology of cambial activity and the growth of conifers in cold temperate regions under a scenario of a warming climate. We defined the mean xylem growing season of pines in this region as 151 days from early May to early October. With the increase in temperatures during 1972–2015, the start date of the xylem growing season advanced by 0.24 days/year, the duration of the xylem growing season increased by 0.27 days/year and the basal area increment of Mongolian pine increased significantly (P < 0.01). The influence of the earlier and longer xylem growing season compensated the negative effect of high initial temperature (14.0–15.0 °C) in some months, resulting in an increase in tree radial increment in this area. The warmer climate will lead to a longer xylem growing season, resulting in greater wood production with an adequate supply of water available.

Оценка эффективности рубок ухода в сухих сосняках Казахского мелкосопочника

According to the current Forest Code of the Republic of Kazakhstan, in the forest plantations of specially protected natural areas, the main forestry measures aimed at the conservation and enhancement of the protective functions of forests are intermediate felling, that is, thinning. Pinus sylvestris L. is one of the main forest-forming species in Kazakhstan. Increasing the stability of forest plantations and the possibility of forming recreationally attractive landscapes through thinning is an urgent problem for plantations growing in arid conditions. The research purpose is to analyze the effectiveness of thinning of high intensity in dry pine forests of the Kazakh Uplands for a 70-year period, using dendrochronological methods. It was proved that in dense pine forests growing in dry conditions, there is an increase in radial growth in each subsequent 10-year period after thinning. It was found with statistical certainty that the greatest response to changes caused by thinning of high intensity was observed between 1949 and 1960. Analysis of indexed tree-ring chronologies using regional curves (indexed average tree-ring chronologies of pine) using a cubic spline function revealed differences in pine radial growth indices from the site where thinning of high intensity were carried out and from the control site (time periods: 1947–1955, 1961–1970, 1981–1990, and 1995–2015). The data obtained show a positive effect of thinning of high intensity on the radial growth of trees in the considered pine forests. In dense pine forests of dry growing conditions of the Kazakh Uplands it is recommended to make 1 or 2 cuttings with thinning intensity of 25–35 % at the age of 20–25 and 40–50, respectively, with subsequent increment thinning.

Effects of climate variability and management on shortleaf pine radial growth across a forest-savanna continuum in a 34-year experiment

We investigated the radial growth response of shortleaf pine (Pinus echinata) to climatic variation and management using tree cores collected in southeastern Oklahoma at the drier, western limit of its range. Beginning in 1984, experimental units were created by various combinations of pine harvest, hardwood thinning, and fire return intervals (1, 2, 3, 4 years and none) that produced ecosystems ranging from mature, closed canopy forest to open savanna. Monthly and seasonal weather for previous- and current-year as well as growing seasons since fire were used to determine the relationship between radial growth and climate variability (1987–2018) for different management regimes. Across all treatments, growing season precipitation (~5% decrease per 100 mm decrease in precipitation), average summer temperature maximum (~7% decrease with 1 °C increase), and previous year’s average October minimum temperature (~6% increase per 1 °C increase) were the variables most frequently correlated with variation in ring width. Annual wood and latewood growth increments were correlated (R2 = 0.60) and generally responded similarly to climate variability, with latewood more sensitive to late growing season conditions. Management with frequent fire that resulted in savanna ecosystems reduced growth sensitivity to annual variation in precipitation relative to trees in a closed-canopy forest condition. Suppressed trees were also less responsive to climate variability than intermediate or co-dominant trees. Both annual wood and latewood growth were reduced by 21–33% the first year after prescribed fire for treatments with a 2- and 3-year fire return interval. Multiple regression combing temperature and precipitation variables as well as time since fire accounted for 55% of the variability in annual ring growth.Our findings indicate that a drier climate with hotter summers will likely reduce the growth of shortleaf pine growing at the western margin of its range while warmer temperatures in October, by extending the growing season, may help ameliorate the effects of warmer summers. Management to reduce stand density, either through thinning or by prescribed fire, may dampen some of the variation of growth in response to climate variability.

Radial Growth of Scots Pine (Pinus sylvestris L.) in Lichen Pine Forests and Woodlands of the Northern Taiga

The vitality structure of forest stands and the annual radial increment of Scots pine trees of different vital state categories growing in the northern taiga middle-aged lichen pine forests and woodlands of the Kola Peninsula have been studied. This study has shown a prevalence (60–75%) of weakened and strongly weakened trees in the Scots pine forests and woodlands; the fraction of healthy trees does not exceed 15–20% (30% in terms of the stand volume). In the age range of 30–85 years, the radial growth of Scots pine trees in the communities studied decreases 1.5- to 3.5-fold, and the annual basal area increases 1.5- to 5-fold. Differentiation of trees of differing vitality in relation to the radial increment is clearly manifested starting from 50 years after the fire. The ratio between the annual basal areas of healthy, weakened, strongly weakened, and dying trees in pine forests and woodlands is 8 : 5 : 2.5 : 1 and 11 : 5.5 : 3.5 : 1, respectively. The difference between the resource potentials of pine woodlands and forests is 1 : 1.6 and is manifested at the level of communities, but not at the level of individuals.

Pine radial growth in the Trans-Baikalian steppe and taiga zones as a reflection of the climatic parameters and lake hydrological regime dynamics

The paper presents the results of the annual rings width research of the trunk test core sampled from standing common pines. The purpose of the research is the analysis of the ability to use the radial recruitment changes of the trees growing in different natural zones for further reconstruction and prognosis of the climatic variables and lake hydrological regime. It was revealed that the dynamics of annual rings width in the steppe zone is characterized by the maximum values of the standard deviation and sensitivity to environmental factors in comparison with taiga zone trees. The radial growth of trees in the steppe zone shows a significant positive reaction to atmospheric precipitation and a negative reaction to air temperature from May to October. The influence of meteorological parameters on the annual growth of pine in the taiga zone is less considerable. The analysis of the synchronicity of changes in pine increments in the steppe zone with interannual fluctuations in the water level of Lake Barun-Torey due to the climatic conditions dynamics showed the significant correlation; therefore, the maximum correlation is observed with lake reaction lag for 4-5 years. Dendrochronological analysis of trees in the taiga zone (Baikal-Stanovoye Upland) revealed only a weak correlation with the average annual level of Lake Bount in the current year. Thus, the tree-ring chronology based on pines of steppe zone can be used for retrodiction of the hydrometeorologic elements.

Радіальний приріст соснових насаджень, створених з різною густотою в Житомирському Поліссі

Досліджено насадження сосни звичайної (Pinus sylvestris L.) в Житомирському Поліссі на стаціонарному досліді № 1 впродовж 2010-2012 років. Проаналізовано величини середнього, максимального та мінімального радіальних приростів сосни звичайної, а також динаміку поточного радіального приросту. Виявлено, що середня величина радіального приросту в насадженнях коливається в діапазоні 2,49-3,70 мм. На варіантах досліду в нaсaджeнняx з початковою густотою 4000, 2000 і 1000 шт.·га-1 відмінність середнього радіального приросту відсутня або знаходиться в діапазоні 1-8 %. Величини максимальних приростів у соснових насадженнях досліду коливаються в діапазоні 5,34-7,32 мм, а величини мінімальних – 0,83-1,36 мм. Продемонстровано динаміку радіальних поточних приростів й різницю між ними. Встановлено, що достовірна різниця коливається в діапазоні 3-34 %. Вона спостерігається мiж нaсaджeннями з початковою гycтoтoю 4000 i 2000 шт.·га-1 у період з 1982-1984 до 1994-1997 рр., між сосняками з початковою кількістю дерев на одиниці площі 2000 і 1000 шт.·га-1 у період з 1982-1985 до 1999-2001 рр., і між насадженнями з початковою густотою 4000 і 1000 шт.·га-1 у період з 1982-1984 до 2006-2010 рр. Зроблено висновки про те, що величина середнього радіального приросту і формування поточного радіального приросту залежать від початкової густоти, а величини максимального та мінімального поточного радіального приростів не залежать від початкової густоти насадження.

Реакція радіального приросту Pinus sylvestris L. на зміну клімату в насадженнях Лівобережного Лісостепу

Досліджено особливості реакції радіального приросту сосни звичайної (Pinus sylvestris L.) на зміну клімату в середньовіковому чистому сосновому насадженні Лівобережного Лісостепу. Використано стандартні дендрохронологічні методики. Виявлено роки мінімального приросту: 1975, 1987 та 2013, що обумовлено високими середньорічними температурами 1975 та 2013 рр. і низькими зимовими температурами 1987 р. Роки максимального приросту (1944, 1957, 1978 та 2004.) відзначалися оптимальним співвідношенням тепла й вологи. Виявлено взаємозв’язки між радіальним приростом сосни й опадами та температурами за два періоди – 1960–1992 та 1985–2017 рр. У другому періоді дерева стали більш чутливими до погодних стрес-чинників унаслідок потепління, про що свідчать результати кореляційного аналізу та функції відгуку. Збільшилася кількість значущих зв’язків між радіальним приростом і кліматичними чинниками в другому періоді внаслідок ослаблення насадження, викликаного зміною клімату. Посилився негативний вплив температур попереднього року та вегетаційного періоду поточного року на радіальний приріст сосни.

Reconstruction of Precipitation by Radial Growth of Scots Pine in the Southern Urals

This work presents the results of analysis of the correlation between radial growth of Scots pine (Pinus sylvestris L.) and the amount of spring–summer precipitation on the Zilair Plateau (Southern Urals). The amount of precipitation from 1776 to 2015 is reconstructed on the basis of the close correlation (r = 0.78) between the growth of late pine wood and the amount of May–June precipitation. The entire interpreted time range includes periods with amounts of precipitation less than average (1888–1893, 1906–1912, 1952–1959, 2008–2012) and wet periods (1779–1783, 1827–1831, 1834–1838, 1878–1883). The longest wet periods are typical of the first half of the time range interpreted (the end of the 18th century and the 19th century), whereas the driest periods are characteristic of the second half (the end of the 19th century, the beginning of the 20th century, the 1950s, and the beginning of the 21st century).

Динамика радиального прироста кедра сибирского Pinus sibirica Du Tour при различных режимах рубок уход

Creation and formation of Siberian pine forests for various purposes, and especially Siberian pine seed orchards, is an urgent issue of Russian forestry. The article deals with the dynamics of the radial growth of Siberian pine Pinus sibirica Du Tour trees after thinning with different modes (method, number of methods, etc.). The analysis was performed both at the stand, and tree levels. The studies were carried out at the experimental plots located in the Khanty-Mansiysk autonomous district and Tyumen region in the middle taiga subzone. As a result of the research it has been established that the response of Siberian pine to thinning depends on intensity, number of methods and timing, as well as on age and morphological structure of Siberian pine on clearings and under the canopy of secondary forests. It was found that extensive (low density) Siberian pine seed orchards are formed both under intensive and systematic thinning. In this case, the average radial growth ranges from 3 to 5 mm/yr, which provides not only a rhythmic progressive growth, but also physiological development. Thereby, after 30–35 years substantially all trees have already entered the generative phase and actively seeding. Single thinning, especially with small selection (less than 50 %) leads to the formation of intensive (high density) seed orchards with an average growth of trunk from 2 to 3 mm/yr. Overgdense, aside from reduction of Siberian pine radial growth, slows down the rate of ontogenetic stages and phases. As a result, in these seed orchards there are trees that have never given cones.For citation: Dynamics of the Radial Growth of Siberian Pine Pinus sibirica Du Tour under Different Thinning Modes. Lesnoy Zhurnal [Russian Forestry Journal], 2019, no. 6, pp. 9–24.DOI: 10.17238/issn0536-1036.2019.6.9