Home – Home – Jornals – Siberian Journal of Forest Science 2018 number 2

Conceptual-methodological and economic bases of plantation forest growing are developed. The mathematical models of the dynamics of the productivity of stands of different tree species in the rich types of the forest-growing conditions of the Middle Volga region, their commodity structure, the stumpage cost and the market price of timber are presented. The algorithm of actions for managing forestry on cultivation of forest plantations is offered. It is noted that in the conditions of fresh dubrava (oak forest) and sudubrava (fresh oak and pine forest), pine and larch stands are the most productive. It is concluded that, taking into account the stumpage cost and the market price of timber, it is most profitable in this region of Russia, in oak forest types of forest conditions, to grow plantations of English oak Quercus robur L., in sudubrava conditions it’s more profitable to grow plantations of Scots pine Pinus sylvestris L., the Siberian larch Larix sibirica Ledeb., and tillet Tilia cordata Mill. In wet, near floodplain and short-flooded ecotopes, it is promising to grow European ash Fraxinus excelsior L. and high-grade poplar Populus crops. Less economic benefit in the current socio-economic conditions will be in the creation of plantations of common spruce Picea abies (L.) H. Karst, aspen Populus tremula L., and weeping birch Betula pendula Roth. The culmination of the average annual increment of the stand stumpage cost, which attests to the age of economic maturity, first occurs in aspen forests (at 45 years), and later - in spruce stands (at 70 years). In oak forests it occurs at the age of 65 years, in tillet stands and in larch crops - at 60 years, in birch forests - at 55 years, in pine crops - at 50 years. In the production of forest raw material plantations, the initial density is of great importance, the optimal values of which are determined by the tree species, the assortment and the economic efficiency of cultivation. Increasing the productivity of the stands and accelerating the process of forest growing is possible with the help of agrotechnical, meliorative and silvicultural measures, applying them considering forest growing conditions and the targeted purpose of plantations.

The DNA-diagnostic results of phytopathogens in 26 forest nurseries of Krasnoyarsk Krai and the Republic of Khakassia in the period from 2014 to 2016 were presented. The objects of research were the plants of conifer species Pinus sylvestris L., Pinus sibirica Du Tour and Picea obovata Ledeb. aged from 1 to 6 years. According to the data of molecular genetic analysis in the forest nurseries of the studied areas, the representatives of 13 genera of pathogenic and conditionally pathogenic fungi that cause diseases of conifers were revealed: Phoma Sacc., Didymella Sacc., Alternaria Nees, Cladosporium Link, Rhizoctonia DC., Lophodermium Chevall., Gremmenia Korf. ( Phacidium Fr.), Sclerophoma Höhn. (teleomorph - Sydowia Bres.), Typhula (Pers.) Fr., Botrytis P. Micheli ex Pers., Gremmeniella M. Morelet ( Scleroderris (Fr.) Bonord.), Septorioides Quaedvl., Verkley & Crous and Epicoccum Link. Seven genera of micromycetes are found in all three surveyed forest zones: taiga, forest-steppe and Southern-Siberian mountain. The most frequently occurred lesions were caused by the sac fungi. Some of the identified diseases practically had not been diagnosed before. In each of the nurseries, the pathogenic microflora was represented by 1-7 species of microscopic fungi, several pathogens were often presented simultaneously on the infected seedlings. In the process of working, the dominant pathogens, connection of pathogens with certain species and with the seedlings age composition have been identified. Such diseases as Phoma blight and Lophodermium needle cast predominated the frequency of occurrence, their relative abundance was 30 % and 28 % respectively of all identified fungal infections of plants. Also, given the climatic conditions of the region, attention should be paid to the phytopathogens - Gremmenia infestans (P. Karst.) Crous and Typhula sp .

When using biomass and net primary production (NPP) databases compiled by the authors for 6 forest-forming species in a number of 6694 and 2192 sample plots correspondingly, a system of regression models of their NPP is designed and some species-specific regularities of NPP distribution in two climatic gradients (natural zonality and climate continentality) are stated. It is found that according to a zonal gradient, aboveground and total NPP in 2-needled pine and spruce-fir forests are monotonically increasing in the direction from the northern to the southern tip of the continent, while larch and birch have the maximum in the southern moderate, and aspen and poplar - in the northern moderate zone, but oak forests do not show any significant pattern. Within a single zonal belt, the aboveground and total NPP of coniferous and deciduous are monotonically decreasing in direction from the Atlantic and Pacific coasts to the continentality pole in Yakutia. The understory NPP of all the species, except oak, monotonically increase towards the subequatorial zone. For oak forests, any clear regularity is not revealed. Within a single zonal belt, when approaching continentality pole, Pinus and Quercus NPP monotonically decreases and in other species, increases. Species-specific patterns in changing the relative indices of NPP (forest stand underground NPP to aboveground one and forest understory NPP to total forest stand one) in gradients of the natural zonality and climate continentality are established.

The principles for the formation of forest typological classification and outlines promising areas for development, allowing to solve problems of not only inventory and forest management, but also mapping forest types are discussed in the paper. The analysis is performed by interpreting the concept of «natural regularity» proposed by D. L. Armand (1975). It is shown when the left side of the pattern is a set of indicators of site condition, structure of forest typological constructions will take into account not only the static indicators of the stands, but also their location, the origin and direction of the succession. For relatively similar climatic conditions, the indicators of the lay of land mainly limit the environment of formation of vegetation cover. The method of mapping forest types provides for consideration of site condition and indicators of stands of forest types. Testing is conducted on a test axis West-Sayan forest district, located in the mountains of southern Siberia. Conjugation types of forests, indicators of the topography revealed through the analysis of literary sources and characteristics of forest types accompanying diagnostic table (Smagin et al., 1980). The work is done in a GIS environment using DEM SRTM and Landsat space images. For indexing locations, the inputs are accepted: altitude (gradation 100 m), flat location, slope up to 20° and 20° slopes with northern and southern exposure. Classification of pixels of satellite images is conducted by the method of unsupervised classification separately for each scene, the high-altitude zone and location, which allows increase of the quality of interpretation, because the types of forests are confined to the topography. However completely avoiding mistakes is not possible. The main reasons are an inaccuracy of the DEM and the hit in one class of spectral brightness of different objects of interpretation. The map legend includes characteristics of the terrain, description of the types of forests, including soil and groundwater conditions, and forest inventory parameters.

Despite a large number of publications covering various aspects of the influence of climatic factors on runoff, this direction in hydrological research acquires a new meaning in connection with the increase in anthropogenic pressure on river systems. In order to identify regional and local features of the hydrological regime of the rivers in Sayan mountain region, the spatial and temporal dynamics of runoff of the main rivers in the study area were analyzed; the analysis of river flow trends against the backdrop of climate change and forest management in the drain areas was performed. Studies have shown that the revealed trends in the annual runoff of the studied rivers differ in type and in magnitude. The hydrological regime of the rivers with the negative trend of annual runoff is determined by the general nature of the humidification of the territory, which overrides the influence of all other factors. Despite a general trend of decreasing precipitation, the positive trend of annual runoff is due to a decrease in evaporation in the drainage areas, which depends both on the temperature regime of the research area and on the anthropogenic transformation of forest vegetation under logging impact. In spite of the considerable variability of annual river flow, trends in runoff coefficients for study rivers vary slightly, indicating the relative stability in water availability. This is due to cumulative effect of anthropogenic transformation of forest vegetation in the drainage areas, i.e. new felling, regeneration on logging sites and creating forest crops. Obtained results show that at the regional level in conditions of anthropogenic pressure on the forests in the drainage areas of medium and small rivers, the trends of climatic parameters, in particular precipitation, are offset by the forest harvesting and subsequent reforestation dynamics at clear cuts.

The influence of experimental burning on ground cover in pine forests of different age stands with dominated herbs and mosses in the Krasnoyarsk forest-steppe was studied. Experimental burning decreased species diversity, percent cover, and biomass of shrubs and herbs. Mosses degraded after fires. The species diversity and biomass of shrubs and herbs increased in 2 years after fire. The greatest species diversity of ground cover was in 60 year old pine forest in 2 years after fire (moderate intensity) (28 species). The percent cover of shrubs and herbs was below pre burning values in 110-years aged stand in 2 years after fire. The seedlings of Scotch pine Pinus sylvestris L. were 35.2 thousand units/ha in 60-years aged pine forest in 2 years after experimental burning. The seedlings of pine were 61.1 thousand units/ha and self-sowing was 14.8 thousand units/ha in the next year after fire. The number of pine shoots was high (51.1 thousand units/ha) and self-sowing was by 3.2 times more than in last year (47.0 thousand units/ha). Experimental burning of low intensity stimulated emergence of pine shoots in 110-years aged stand where their amount were 31.1 thousand units/ha in 3 month after fire. The reforestation was presented by pine shoots (31.5) and self-sowing (2.0 thousand units/ha) in next year after experimental burning. The number of pine shoots was 17.4 thousand units/ha and self-sowing increased by 11.0 times or 21.9 thousand units/ha in two years after burning.

Boreal forests are one of the main carbon (С) pools on the planet. Decomposition of the litter is a main mechanism of C accumulation in soil. This process is often influenced by fires. Thus, we need to enhance our understanding about decomposition of the litter in post-fire forests to better understand the mechanism of C accumulation in boreal forests. Here, we studied initial stages of decomposition of litter in the post-fire forest (12 years after fires) and in the background larch forest located in the Tukuringra mountain range in the northern part of the Amur oblast. We present the results of a field experiment on the decomposition of the main typical fractions of larch forest. We used the litter bags method for studying rate of decomposition litter (leaves, grass, branches and needles). After 150 days mass loss of litter was 36.7 % of initial mass in the post-fire forest and 39.9 % in the background forest. Mass loss was most rapid in the first 75 days of the experiment in the both cases. In both plots the rate of decomposition of litter was decreased in order: grass - leaves - needles - branches. In both the post-fire and background forests, rate of litter decomposition is a function of moisture. Soil acidity was higher in post-fire forest than background forest (5.3 and 4.8, respectively, p < 0.01). However, this soil property does not influence early stages of litter decomposition in either case.