Wood anatomy chronologies of Scots pine in the foothills of the Western Sayan(Siberia)

Recent methodological advances in quantitative wood anatomy have provided new insights into the climatic responses of radial growth at the scale of cell structure of tree rings. This study considered long-term chronologies of tracheid measurements, indexed by a novel approach to separate their specific climatic responses from signal recorded in cell production(closely reflected in tree-ring width). To fill gaps in understanding the impact of climate on conifer xylem structure, Scots pine(Pinus sylvestris L.)trees > 200 years old were selected within the forest-steppe zone in southern Siberia. Such habitats undergo mild moisture deficits and the resulting climatic regulation of growth processes. Mean and maximum values of cell radial diameter and cell wall thickness were recorded for each tree ring.Despite a low level of climatogenic stress, components of cell chronologies independent of cambial activity were separated to obtain significant climatic signals revealing the timing of the specific stages of tracheid differentiation. Cell expansion lasted from mid-April to July and was impacted similarly to tree-ring width(stimulated by precipitation and stressed by heat), maximum cell size formed late June. A switch in the climatic responses of mean anatomical traits indicated transition to latewood in mid-July. Secondary wall deposition lasted until mid-September, suppressed by end of season temperatures. Generally, anatomical climatic responses were modulated by a less dry May and September compared with summer months.

Fuel characteristics, loads and consumption in Scots pine forests of central Siberia

Forest fuel investigations in central and southern Siberian taiga of Scots pine forest stands dominated by lichen and feather moss ground vegetation cover revealed that total aboveground biomass varied from 13.1 to 21.0 kg/m 2.Stand biomass was higher in plots in the southern taiga,while ground fuel loads were higher in the central taiga.We developed equations for fuel biomass(both aerial and ground)that could be applicable to similar pine forest sites of Central Siberia.Fuel loading variability found among plots is related to the impact and recovery time since the last wildfi re and the mosaic distribution of living vegetation.Fuel consumption due to surface fi res of low to high-intensities ranged from 0.95 to 3.08 kg/m 2,that is,18–74%from prefi re values.The total amount of fuels available to burn in case of fi re was up to 4.5–6.5 kg/m 2.Moisture content of fuels(litter,lichen,feather moss)was related to weather conditions characterized by the Russian Fire Danger Index(PV-1)and FWI code of the Canadian Forest Fire Weather Index System.The data obtained provide a strong foundation for understanding and modeling fi re behavior,emissions,and fi re eff ects on ecosystem processes and carbon stocks and could be used to improve existing global and regional models that incorporate biomass and fuel characteristics.

Zonal aspects of the influence of forest cover change on runoff in northern river basins of Central Siberia

Background:Assessment of the reasons for the ambiguous influence of forests on the structure of the water balance is the subject of heated debate among forest hydrologists.Influencing the components of total evaporation,forest vegetation makes a significant contribution to the process of runoff formation,but this process has specific features in different geographical zones.The issues of the influence of forest vegetation on river runoff in the zonal aspect have not been sufficiently studied.Results:Based on the analysis of the dependence of river runoff on forest cover,using the example of nine catchments located in the forest-tundra,northern and middle taiga of Northern Eurasia,it is shown that the share of forest cover in the total catchment area(percentage of forest cover,FCP)has different effects on runoff formation.Numerical experiments with the developed empirical models have shown that an increase in forest cover in the catchment area in northern latitudes contributes to an increase in runoff,while in the southern direction(in the middle taiga)extensive woody cover of catchments“works”to reduce runoff.The effectiveness of geographical zonality in regards to the influence of forests on runoff is more pronounced in the forest-tundra zone than in the zones of northern and middle taiga.Conclusion:The study of this problem allowed us to analyze various aspects of the hydrological role of forests,and to show that forest ecosystems,depending on environmental conditions and the spatial distribution of forest cover,can transform water regimes in different ways.Despite the fact that the process of river runoff formation is controlled by many factors,such as temperature conditions,precipitation regime,geomorphology and the presence of permafrost,the models obtained allow us to reveal general trends in the dependence of the annual river runoff on the percentage of forest cover,at the level of catchments.The results obtained are consistent with the concept of geographic determinism,which explains the contradictions that exist in assessing the hydrological role of forests in various geographical and climatic conditions.The results of the study may serve as the basis for regulation of the forest cover of northern Eurasian river basins in order to obtain the desired hydrological effect depending on environmental and economic conditions.

Spatial analysis of vegetation cover response to climate trends in Khakassia(South Siberia)

An analysis of the changes in vegetation cover on the territory of the Republic of Khakassia in 2000–2021 due to climatic trends was carried out based on the MODIS data.The changes in vegetation cover were estimated based on trends in Normalized Difference Vegetation Index(NDVI)and Enhanced Vegetation Index(EVI).In general,in the 21st century,an increase in the biomass of vegetation cover is observed.Positive trends were observed in 16%–22%of the territory,and negative only in 1%–3%.For about 20%of the analyzed territory,a significant influence of climate on the changes in vegetation cover was revealed.The most pronounced negative impact on vegetation cover was caused by summer air and soil temperatures,spring temperature,and summer winds,and the positive impact was caused by summer precipitation and soil moisture.The response of the vegetation cover to climate was non-uniform concerning the topography.Thus,a significant correlation with the amount of precipitation was observed for~20%–35%of vegetation growing below 600 m above sea level and for less than 5%above this elevation.The negative effect of summer temperatures on plants prevailed mainly at an elevation below~1400 m above sea level.Projected climate change is likely to lead to significant degradation of vegetation in the steppe and foreststeppe in Khakassia in the coming decades.

Suspension Culture and Somatic Embryogenesis of Korean Pine

Korean pine is an important afforestation tree species in Northeast China,which has a high ecological and economic value.Although regeneration of somatic embryogenesis using immature zygotic embryos of Korean pine as explants has been successful,it cannot be applied to automation and large-scale production.Therefore,we urgently need a method that can increase the output of somatic embryos(SEs)to meet the needs of large-scale production.We used Korean pine 1-1 and 1-100 cell lines as research materials to evaluate the effects of inoculum-density,culture time,orbiting speed,vessel volume,plant growth regulator(PGR)concentration,and carbon source on the proliferation of embryogenic tissue(ET).The somatic embryogenesis ability of ET cultured in different liquid suspension media was also evaluated.We found that during liquid suspension culture of Korean pine ET,the sedimented cell volume(SCV),fresh weight(FW)and dry weight(DW)were affected by inoculumdensity,culture time,orbiting speed,2,4-D concentration,6-BA concentration and carbon source type.Fourty mg⋅mL^(−1)ET were transferred to a 200 mL Erlenmeyer flask containing 20 mL liquid medium,and cultured at 100 rpm/min for 14 days to obtain the maximum proliferation.In addition,we also found that SCV,FW and DW were higher when PGRs were reduced in the liquid suspension medium.The substitution of maltose for sucrose resulted in slow growth of cultures and limited SE yield(13 SEs g^(−1)FW).Although culture proliferation was high at 50 rpm,SE yield was inhibited by 48%compared with 100 rpm(50 rpm=33 SEs g^(−1)FW;100 rpm/min=70 SEs g^(−1)FW).Cultivation in low-concentration PGR(1.15μM⋅L^(−1)2,4-D,0.25μM⋅L^(−1)6-BA)and sucrose liquid medium at 100 rpm/min(80 SEs g^(−1)FW)could not only promote culture proliferation but also increase SE yield.The determination of the suspension culture scheme of Korean pine ET provides a reference for further expansion to bioreactor culture in the future and lays a foundation for the automation and scale of somatic embryogenesis of Korean pine.

<i>Abies sibirica</i>Male Reproductive Cones Developmental Shift at Introduction

A strong effect of climate on phenological events in conifers has been documented by several studies. To study adaptation of reproductive processes in Abies sibirica Ledeb. to changing environment, the phenology of the development of the species male reproductive cones at introduction was studied. Phenological shift in Abies sibirica meiosis and pollination was observed. An earlier start of male bud reproductive development is founded in V.N. Sukachev Institute of Forest Arboretum resulted in increasing meiosis and pollen irregularities. Insufficient high quality pollen in the species at its pollination stage may be a major factor responsible for the incapability to produce the viable seeds in quantities sufficient for pollination in seed gardens. Responses of the fir male cone development to the current environmental conditions at the Arboretum may be considered as a model of adaptation of the species to climatic changes.