Influence of moss and lichen spatial mosaics on radial growth of Gmelin larch (Central Evenkia)

The results of research studies on the influence of high moss-and-lichen mosaicity typical for the northern taiga in Central Evenkia on the dynamics of radial growth of Gmelin larch trees (Larix gmelinii (Rupr.) Rupr.) are reported. Three sample plots were laid out in the larch ledum–cowberry–green moss forest on the northwest facing slope (8°–10°) in close proximity to each other; they differed in the proportions of area occupied by the principal components of a moss–lichen cover (Aulacomnium turgidum, Pleurozium schreberi, Cladonia rangiferina, and Hylocomium splendens), spatial distribution, and thermal properties of seasonally thawed soil layers. The worst thermal soil properties under the current climatic conditions have determined the comparatively low radial growth of trees in the sampling area, reduced response to air-temperature variations in the period of preseason cambium activity and at the beginning of the radial growth period, and heightened the response to this factor at the end of a season.     

A microbiological characterization of the permafrost soil of Tit-Ary Island (Yakutia)

The microbiological composition of the soil of the unique Tit-Ary Island in the lower reaches of the Lena River has been studied in detail for the first time. The specific features of the microbial population of the cryosolic soil have been revealed, including a high number of individuals of all microbial groups (10⁴–10⁸ CFU/g), comparable to the density of microorganisms in the steppe soil of Transbaikalia, and the specific pattern of their distribution in the soil profile without a decrease in their count with depth. Oligonitrophilic bacteria were prevalent in the humic gley soil of polygonal ridged tundra; their number varied from 70 × 10³ to 330 × 10⁶ CFU/g soil.     

塞罕坝地区人工针叶林径向生长对水热条件的响应

树木生长对水热条件响应的研究在揭示气候变化的生态影响中发挥着重要作用。为探讨水热因子对亚洲最大的人工针叶林生长的影响及不同树种生长-水热因子关系特征,选取塞罕坝地区龄级较高的人工针叶林群落的优势树种华北落叶松(Larix principis-rupprechtii)和樟子松(Pinus sylvestrisvar.mongolica),采集树木年轮样芯,并通过年轮宽度数据建立标准年表。通过分析两树种的标准年表数据与气温、地温、降水量、饱和水汽压差等水热因子的相关关系,揭示不同树种对水热因子响应的异同。研究结果显示:华北落叶松的生长受到6、7、9月的干旱胁迫和8月过多降水的限制,同时受到冬季较高的平均地温和降水的促进;樟子松的生长则受到夏季的高温干旱胁迫和8月过多降水的抑制,但8月较高的平均地温以及春季较高的平均最低地温对樟子松的生长存在明显促进作用。塞罕坝地区华北落叶松受干旱胁迫强于樟子松,而樟子松受较低地温的胁迫强于华北落叶松。考虑到区域增温的趋势,推断樟子松应是更适合在塞罕坝等半干旱地区继续进行大面积人工造林和经营管理的树种。     

Tree-ring growth of Gmelin larch under contrasting local conditions in the north of Central Siberia

While the forest-tundra zone in Siberia, Russia has been dendroclimatologically well-studied in recent decades, much less emphasis has been given to a wide belt of northern taiga larch forests located to the south. In this study, climate and local site conditions are explored to trace their influence on radial growth of Gmelin larch (Larix gmelinii (Rupr.) Rupr.) trees developed on permafrost soils in the northern taiga. Three dendrochronological sites characterized by great differences in thermo-hydrological regime of soils were established along a short (ca. 100 m long) transect: on a river bank (RB), at riparian zone of a stream (RZ) and on a terrace (TER). Comparative analysis of the rate and year-to-year dynamics of tree radial growth among sites revealed considerable difference in both raw and standardized tree-ring width (TRW) chronologies obtained for the RZ site, characterized by shallow soil active layer depth and saturated soils. Results of dendroclimatic analysis indicated that tree-ring growth at all the sites is mostly defined by climatic conditions of a previous year and precipitation has stronger effect on TRW chronologies in comparison to the air temperatures. Remarkably, a great difference in the climatic response of TRW chronologies has been obtained for trees growing within a very short distance from each other. The positive relation of tree-ring growth with precipitation, and negative to temperature was observed in the dry site RB. In contrary, precipitation negatively and temperature positively influenced tree radial growth of larch at the water saturated RZ. Thus, a complicate response of northern Siberian larch forest productivity to the possible climate changes is expected due to great mosaic of site conditions and variability of environmental factors controlling tree-ring growth at different sites. Our study demonstrates the new possibilities for the future dendroclimatic research in the region, as various climatic parameters can be reconstructed from tree-ring chronologies obtained for different sites.     

The intensity of phytodetrite decomposition in larch forest of the permafrost zone in Central Siberia

Based on the results of long-term investigations, quantitative assessment of phytodetrite mineralization rates is provided. Their role in the biological cycle of larch stands growing in the permafrost zone of Central Evenkia is discussed. It is demonstrated that their destruction in the subshrub-sphagnum and cowberry-green moss larch stands is extremely slow, the plant litter contains the most cecalcitrant organic matter demonstrating the lowest decomposition coefficient of 0.03—0.04 year^?1, whereas fresh components of the plant litter have 3- to 4-fold higher values. An insignificant input of N and C from the analyzed mortmass to the soil has been registered. It has been revealed that the changes in N and C in the decomposition components are closely related to the quantitative dynamics (biomass) of microorganisms, such as hydrolytics and, especially, micromicetes.     

林龄对红松和落叶松人工林土壤温室气体通量的影响

探讨人工林发育过程中土壤温室气体排放及其机制,可为森林温室气体通量估算提供理论依据.采用室内培养方法研究了黑龙江省帽儿山地区不同林龄(15、30和50年生)红松(Pinus koraiensis)和落叶松(Larix gmelinii)人工林土壤温室气体排放/吸收速率及其调控因素.结果 表明:30年生红松和落叶松人工林...     

Seasonal and spatial variability of elemental concentrations in boreal forest larch foliage of Central Siberia on continuous permafrost

We measured the seasonal dynamics of major and trace elements concentrations in foliage of larch, main conifer species of Siberia, and we analyzed cryogenic soils collected in typical permafrost-dominated habitats in the Central Siberia. This region offers a unique opportunity to study element fractionation between the soil and the plant because of (i) the homogeneous geological substratum, (ii) the monospecific stands (Larix gmelinii) and (iii) the contrasted habitats (North-facing slope, South-facing slope, and Sphagnum peatbog) in terms of soil temperature, moisture, thickness of the active layer, tree biomass and rooting depth. The variation of these parameters from one habitat to the other allowed us to test the effects of these parameters on the element concentration in larch foliage considered with high seasonal resolution. Statistical treatment of data on larch needles collected 4 times in 3 locations during entire growing season (June–September) demonstrated that : (1) there is a high similarity of foliar chemical composition of larch trees in various habitats suggesting intrinsically similar requirements of larch tree growth for nutrients, (2) the variation of elemental concentrations in larch needles is controlled by the period (within the growing season) and not by the geographical location (South-facing slope, North-facing slope or bog zone) and (3) there are three groups of elements according to their patterns of elements concentration in needles over the growing season from June to September can be identified: (1): nutrient elements [P, Cu, Rb, K, B, Na, Zn, Ni and Cd] showing a decrease of concentration from June to September similar to the behaviour of major nutrients such as N, P and K; (2): accumulating elements [Ca, Mg, Mo, Co, Sr, Mn, Pb and Cr] showing an increase of concentration from June–July to September; (3): indifferent elements [Al, Zr, Fe, Ba, Ti, REEs (Pr, Nd, Ce, La, Gd, Er, Dy, Tb, Lu, Yb, Tm, Sm, Ho, Eu), Y, Th and U] showing a decrease of concentration from June to July and then an increase of concentration to September. A number of micronutrients (e.g., Cu, Zn) demonstrate significant resorption at the end of growing season suggesting possible limitation by these elements. Although the intrinsic requirement seems to be similar among habitats, the total amount of element stored within the different habitats is drastically different due to the differences in standing tree biomass. The partitioning coefficients between soil and larch appear to be among the lowest compared to other environments with variable plants, soils and climates. Applying the “space for time” substitution scenario, it follows that under ongoing climate warming there will be an increase of the element stock following enhanced above-ground biomass accumulation, even considering zero modification of element ratios and their relative mobility. In this sense, the habitats like south-facing slopes can serve as resultant of climate warming effect on element cycling in larch ecosystems for the larger territory of Central Siberia.     

Influence of Gmelin larch trees on postfire restoration of forest communities in the permafrost zone of Central Siberia

This article shows the phytocoenotic role of individual postfire trees of the Gmelin larch under conditions of the permafrost zone of Central Siberia. On the basis of the vital state of the trees, the limits of their influence on the recovery of the species of the lower layers of phytocenosis are defined and the formation of the new stand generation is shown.     

Water balance and adaptation strategy in insects of Central Yakutia to extreme climatic conditions

Original experimental data describing the strategy for cold adaptation of the winter form of blackveined white Aporia crataegi L. living in Central Yakutia, a region with a harsh continental climate and long and very cold winters, are presented in comparison with other insects of Yakutia. Open wintering insects were shown to develop an efficient water-saving mechanism in a frozen state. This can be significant for their survival in post-diapause. Certain relationships between water balance, wintering mode, and strategy for cold adaptation have been revealed by the example of several insect species of this region in comparison with insects living in less severe climatic conditions.     

Carbon and nitrogen status of litterfall, litter decomposition and soil in even-aged larch, red pine and rigitaeda pine plantations

The carbon (C) and nitrogen (N) status in forest ecosystems can change upon establishment of plantations because different tree species have different nutrient cycling mechanisms. This study was carried out to evaluate C and N status of litterfall, litter decomposition and soil in three adjacent plantations consisting of one deciduous (larch: Larix leptolepis) and two evergreen (red pine: Pinus densiflora; rigitaeda pine: P. rigida × P. taeda) species planted in the same year (1963). Both the pine plantations showed comparatively higher C input from needle litter but significantly lower N concentration and input than the larch plantation (P < 0.05). During the decomposition process, the deciduous larch needle litter showed low C concentration and C remaining in soil, but high N concentration and N remaining in soil compared to the two evergreen pine needle litters. However, the soil C and N concentration and their content at a soil depth of 0–10 cm were not affected significantly (P > 0.05) by the plantation type. These results demonstrate the existence of considerable variation in C and N status resulting from needle litter input and litter decomposition in these three plantations grown at sites with similar environmental conditions.     

Post-fire restoration of organic substance in the ground cover of the larch forests in permafrost zone of Central Evenkia

The role of ground fires in transformation of organic substance in the ground cover of larch stands in the permafrost zone of Central Siberia was studied as well as the post-fire restoration dynamics of organic substance. Ground fires lead to is a considerable decrease in concentrations and resources of organic carbon and its individual fractions in the ground cover and their restoration takes many decades.     

Cold adaptation in insects of Central Yakutia

The mode of cold hardening was for the first time assessed for 20 insect species living in the extremely cold climate of Yakutia. All insects tested were found to adapt through freeze tolerance, producing ice-nucleating agents that cause the hemolymph to freeze at high subzero temperatures. For the first time ice-nucleating agents were demonstrated in Lepidoptera. Pieris rapae exemplified the possibility of switchover in the survival strategy depending on the climatic conditions.     

落叶松土壤有机磷形态与林木生长量的关系

采用Bowman-Cole有机磷分级体系,对落叶松人工林不同发育阶段根际与非根际土壤活性有机磷、中等活性有机磷、中稳性有机磷和高稳性有机磷含量的变化及其与有效磷和林木生长量的关系进行了研究。结果表明,构成落叶松人工林土壤有机磷的主要成分是中等活性有机磷和中稳性有机磷,两者之和占有机磷总量的77.07％～86．68％,根际土壤活性有机磷和中等活性有机磷是不同发育阶段土壤有效磷的主要来源,根际土壤有机磷总量、活性有机磷含量、中稳性有机磷含量和高稳性有机磷含量从幼龄林到近熟林随林龄递增而降低,近熟林之后有所增加,根际土壤中等活性有机磷含量随林龄变化不明显,非根际土壤各形态有机磷含量随林龄递增而呈波动性增加趋势,各发育阶段林木胸径、树高定期平均生长量与活性有机磷含量和有效磷含量关系最为密切。     

Effect of soil strength on root growth under different water conditions

The objective of this study was to determine the effects of soil water and soil strength on root growth in situations where the individual effects of both of these factors were important. Three grain legumes were grown from pre-germinated seeds for five days on 50-mm compacted columns of two major soils of Sri Lanka. Four or five levels of bulk density (1.1 to 1.8 Mg.m^–3) and five or six levels of matric potential (–0.02 to–2.0 MPa) were used.Soil strength and matric potential effects on root growth were independently significant for most crop and soil combinations. Under high (wet) matric potential (>–0.77 MPa) soil conditions, the effect of soil water on root growth was evident only in its effect on soil strength. Bulk density had a significant effect on root growth independent of soil strength and matric potential in three cases.For all crops and soils, root penetration was 80% of the maximum or greater when the average soil strength (soil water not limiting) was 0.75 MPa or less, and when the average matric potential (soil strength not limiting) was –0.77 MPa or greater (wetter). Root penetration was 20% of the maximum or less when the soil strength was greater than 3.30 MPa (soil water not limiting), and when matric potential (soil strength not limiting) was less than –3.57 MPa. The use of pre-germinated seeds, which contained imbibed water, combined with a lack of water loss from the closed chambers containing the plants is the probable cause for the very low (–3.57 MPa) matric potential that allowed root growth at 20% of the maximum.     

不同林龄、树种落叶松人工林径向生长与气候变化的关系

研究人工林径向生长与气候变化的关系对全球气候变暖背景下人工林合理经营有着重要的意义。该文对在辽东山区广泛栽培的黄花落叶松(Larix olgensis)和日本落叶松(Larix kaempferi)人工林, 运用树木年轮气候学方法建立了辽宁草河口和湾甸子林场落叶松人工林年表, 分析了落叶松径向生长对气候变化的响应以及气候条件、树种、立地条件和林分因子(林龄、密度、蓄积量等)的相对影响程度。结果发现在影响年轮-气候关系的因素中, 气象因子的潜在蒸发散(PET)的影响力最大; 林龄、密度和蓄积量同时也具有重要的影响作用。中龄落叶松人工林径向生长主要与气温呈正相关关系, 成熟落叶松人工林径向生长主要与气温呈负相关关系; 而其他因素, 如树种、立地条件等的影响作用不大。这表明在气候变暖背景下随着林龄增加, 林分会逐渐受到气温升高导致的水分亏缺的限制, 导致明显的生长下降趋势, 因而气候变暖对成熟落叶松人工林威胁更为严重, 所以要注重对成熟林的优先保护, 同时可以预测, 随着东北地区今后气候进一步变暖, 可能将逐步影响到林龄更小的林分的生长, 因此需要进一步研究如何在落叶松人工林经营中采取科学的措施来更好地应对未来气候变化。     

The effect of various disturbing factors on the radial increment in pine forests of Central Siberia

The results of study of regeneration periods in pine forests after natural and anthropogenic disturbanses have been presented. It has been found that the rate of recovery depends on the type of disturbing factor. The differentiated effect of climatic factors (air temperature, amount of precipitation) on the growth rate of forests with different types of disturbances has been investigated.