Expansion of Juniperus sibirica Burgsd.as a response to climate change and associated effect on mountain tundra vegetation in the Northern Urals

Shrub expansion into arctic and alpine tundra is one of the prominent vegetation changes currently underway.We studied the expansion of shrub vegetation into high elevation tundra in the Kvarkush Range of the Northern Ural mountains,Russia.Age structure analysis of the dominant shrub Juniperus sibirica Burgsd.seems to support ongoing upslope advance of shrubs,a process particularly active in the second half of the 20 th century.We found a close connection between the expansion of shrub vegetation and the general change in climatic conditions of the cold season(months with mean airtemperature below 0°Сfrom November to March).In general,the greatest influence on the distribution of J.sibirica is exerted by the climate conditions of the beginning(November-January)and the end(March)of the cold season.With increasing elevation,the correlation coefficients between the establishment of J.sibirica shrubs and the precipitation of the beginning of the cold season increased,and reached maximum values at the top elevation level of the study area.However,the upwards shift of J.sibirica into typical mountain tundra does not lead to changes in the ecological structure of vegetation at this stage,but simply a decrease in the area of mountain tundra.

Influence of Different Forest Management Techniques on the Quality of Wood

The issue of accelerated forestry plantation with high-quality wood using the best soils in terms of productivity,fertilizers,and intensive treatment has become quite relevant due to increased demand for forestry products and higher requirements for environmentally friendly use of forest resources.This paper presents the results of a study on the impact of various techniques for treating coniferous plantations,including thinning,fertilization,and herbicide processing,on wood quality key indicators.The paper examined the wood density,correlation of early and late wood zones,and the cell wall thickness for 38-year-old pine trees grown on the sample plots of Siversky leskhoz(Leningrad region,Gatchinskiy district)at different treatment and density control techniques.It has been established that the highest basis density of wood corresponds to the samples grown at the density variant of 1 t/ha and double herbicides treatment,and the lowest basis density value was recorded at the option of 4 t/ha with combined treatment.It has been shown that the increase of width index for early wood is influenced by the lower density of 1 t/ha and one-time herbicide treatment,for late wood–by the lower density of 1 t/ha and repeated treatment with herbicides.The increase in average cell wall thickness for early and late wood is observed when the density increases up to 4 t/ha and double herbicides treatment.The results obtained provide a valuable scientific contribution to general forestry knowledge and have practical value in plantation forestry.

Are There Differences in the Response of Natural Stand and Plantation Biomass to Changes in Temperature and Precipitation?A Case for Two-needled Pines in Eurasia

A comparative discussion of the advantages and disadvantages of natural stands and plantations,including in terms of their productivity and stability,began from the moment of the first forest plantings and continues to this day.In the context of the progressive replacement of natural forests by plantations due to deforestation,the question of how will change the carbon storage capacity of forest cover when replacing natural forests with artificial ones in a changing climate becomes extremely relevant.This article presents the first attempt to answer this question at the transcontinental level on a special case for two-needled pine trees(subgenus Pinus L.).The research was carried out using the database compiled by the authors on the single-tree biomass structure of forest-forming species of Eurasia,in particular,data of 1880 and 1967 of natural and plantation trees,respectively.Multi-factor regression models are calculated after combining the matrix of initial data on the structure of tree biomass with the mean January temperature and mean annual precipitation,and their adequacy indices allow us to consider them reproducible.It is found that the aboveground and stem biomass of equal-sized and equal-aged natural and plantation trees increases as the January temperature and precipitation rise.This pattern is only partially valid for the branches biomass,and it has a specific character for the foliage one.The biomass of all components of plantation trees is higher than that of natural trees,but the percent of this excess varies among different components and depends on the level of January temperatures,but does not depend at all on the level of annual precipitation.A number of uncertainties that arose during the modeling process,as well as the preliminary nature of the obtained regularities,are noted.

Climate shapes the spatiotemporal variation in color morph diversity and composition across the distribution range of Chrysomela lapponica leaf beetle

Color polymorphism offers rich opportunities for studying the eco-evolutionary mechanisms that drive the adaptations of local populations to heterogeneous and changing environments.We explored the color morph diversity and composition in a Chrysomela lapponica leaf beetle across its entire distribution range to test the hypothesis that environmental and climatic variables shape spatiotemporal variation in the phenotypic structure of a polymorphic species.We obtained information on 13617 specimens of this beetle from museums,private collections,and websites.These specimens(collected from 1830-2020)originated from 959 localities spanning 33°latitude,178°longitude,and 4200 m altitude.We classified the beetles into five color morphs and searched for environmental factors that could explain the variation in the level of polymorphism(quantified by the Shannon diversity index)and in the relative frequencies of individual color morphs.The highest level of polymorphism was found at high latitudes and altitudes.The color morphs differed in their climatic requirements;composition of colour morphs was independent of the geographic distance that separated populations but changed with collection year,longitude,mean July temperature and betweenyear temperature fluctuations.The proportion of melanic beetles,in line with the thermal melanism hypothesis,increased with increasing latitude and altitude and decreased with increasing climate seasonality.Melanic morph frequencies also declined during the past century,but only at high latitudes and altitudes where recent climate warming was especially strong.The observed patterns suggest that color polymorphism is especially advantageous for populations inhabiting unpredictable environments,presumably due to the different climatic requirements of coexisting color morphs.