Home – Home – Jornals – Siberian Journal of Forest Science 2022 number 4

The results of the local fires reconstruction based on the stratigraphic analysis of the peat deposit in the right-bank part of the Dubches River valley (middle taiga of the Yenisei Siberia) in the Holocene are presented. The object of research was the raised pine-shrub-sphagnum bog with a well-developed tree layer with Scots pine ( Pinus sylvestris L.). The deposit thickness was 4.15 m, its age was interpreted by 11 radiocarbon dates. The bottom peat layer age was 11802 ± 52 ¹⁴C years ago. In a peat core at depths of 3.25, 3.15, 2.90, 2.65 m, traces of fires were found in the form of pyrogenic layers. Reconstruction of the fire dynamics was carried out according to the method of counting macroscopic particles of charcoal “Charcoal”. The time, periodicity and intensity of fires on dry areas surrounding the bog have been established. Four periods were identified in the dynamics of local fires: about 12000-10000, 8250-7250, 6300-4000, 2400 cal. a BP (calibrated age before present). The reliable peaks of charcoal inflow occurred on the following dates: 11600, 11150, 10500, 7800, 5900, 5450, 4600, 1900, 1200 and 250 cal. a BP. It is noted that the highest fire activity was observed in the early Holocene, as evidenced by the increased content of macrocharcoals in peat. The main cause of the fires was probably the abnormally dry spring-summer seasons due to the dry and warm climate. The bog was traversed by fire during: 7790, 7030, 5610 and 4890 cal. a BP. The pyrogenic destruction of peat was minimal, which indicated a weak or medium intensity of the peat fire. Fires in the bog contributed to the activation of the forest formation process. In the late Holocene, the effect of fires on the bog ceased and forest phytocenoses were replaced by heavily watered ridge-hollow complexes.

The studies were carried out in forest peat soils of swampy river valleys of the eastern macroslope of the Kuznetsk Alatau. The content of macro- and microelements in the layer of modern soils (0-30 cm) varies greatly (Cv 42-88 %). The weighted average amount (taking into account the thickness of soil horizons and peat areas) within the orographic profile of 1087-573 m a. s. l. is: Fe₈₆₂₃ > Al₇₂₉₅ > Mn₃₃₅ > Sr₂₃₀ > Zn_37.8 > Cr_15.4 > Cu_13.2 > Ni_9.9 > Pb_4.6 > Co_3.4 > Cd_0.21, mg/kg. The methods of multidimensional statistical analysis have been used to structure peat soils according to the content of ash elements into three clusters corresponding to altitudinal gradient - 1087, 832-622, 573 m a. s. l. Zn and Fe have the greatest discriminating ability (82.6 %). A smaller share of the difference is provided by Cu, Ni (17.4 %). The topographic series of river valley peat soils are determined by the hydrogeochemical zonality of groundwater, as well as the removal of elements by lateral migration flows. For the first time, the boundaries of the vertical altitudinal zonality of peat soils are statistically were proved by the content of mineral elements and the geochemical composition of the selected ecotopic series (clusters) of soils is characterized. Only Pb and Cd accumulate in the soils of the autonomous landscape (highlands). In comparison with it, in the cluster of soils of the middle highlands, the amount of most ash elements increases by an average of 2 times. In the low mountains, the intensity of accumulation weakens somewhat. In the soil profile, the radial geochemical migration of iron as a characteristic element of swamps is more strongly positively correlated with the ash content of the peat substrate, strontium - with the soil pH, Cu and Mn - with fulvic acids. In the current period, no technogenic degradation of peat soils of the eastern macroslope of the Kuznetsk Alatau has been detected. The ecological and geochemical features of mountain peat soils are consistent with the characteristics of the natural biogeochemical provinces on the south of Central Siberia, within which they develop.

The results of external impacts on forest ecosystems, regardless of their origin, are expressed in a certain degree of degradation of the forest ecosystem and, as a rule, involve the identification of damage. The paper shows that before the impact, the cost of stands can be represented as the sum of ecosystem (ecological and resource) functions: C = СCi, where Ci is the cost of the i-th function of the n considered. The calculation is performed relative to a certain function, the cost of which is known. As such a function, the tax rate of payment for wood is used. It is also possible to calculate the relative market price of wood. The final values of the value of ecosystem functions, at the same time, will differ in proportion to the ratio of tax and market prices. After exposure, the cost of stands is determined by adjusting the cost of each ecosystem function. The difference between before and after exposure determines the amount of damage. In accordance with the intended purpose, as well as due to the difference in forest inventory indicators of the stands, estimates of the significance of ecosystem functions may radically differ. This means that the distribution of the shares of significance for each stand is individual. The sequence of identifying the cost of stand and further damage is demonstrated by the example of a section of pine-larch forest destroyed by fire on the territory of the Lake Uchum resort. It was found that before the fire, the cost of stand was 156 700 rubles/ha, after the fire it decreased to 27819 rubles/ha; damage was determined in the amount of 128881 rubles/ha.

The study focuses on the thermal analysis and flash pyrolysis of bark of Siberian larch ( Larix sibirica Ledeb.) and Scots pine ( Pinus sylvestris L.). Using thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC), a number of patterns of thermal decomposition of bark were established. The fourth derivatives of the DTG contours revealed differences in the “fractionality” of mass loss during heating of the bark samples. The thermal decomposition kinetics of bark was investigated using the Ozawa - Flynn - Wall isoconversion method. The obtained dependence of the activation energy ( E _a) on the conversion degree was used to calculate the thermodynamic parameters (Δ H , Δ G and Δ S ) of thermal decomposition. The mean values of E _a, Δ H , Δ G and Δ S were 206.7, 201.1, 248.7 kJ/mol and -78.0 J/(mol×K) for larch bark (LB) and 235.3, 229.7, 310.6 kJ/mol and -129.4 J/(mol×K) for pine bark (PB). The composition of mono-, sesqui-, diterpenes and oxygen-containing hydrocarbons of bark was determined by headspace GC/MS analysis. 37 and 41 volatile organic compounds were identified for LB and PB, respectively. The thermal stability of LB and PB was characterized using recalcitrant indices calculated from TG and DSC data. Integral values of exothermic effects of thermo-oxidative degradation were 15.1 kJ/g for LB and 15.9 kJ/g for PB. 55 flash pyrolysis products were identified, which accounted for 77.6 % of the total peak area for LB and 89.7 % for PB.

Attracting new species and varieties of ornamental plants is an urgent task of greening and landscape construction. The purpose of the study was to generalize the experience and investigate dynamics of the development of vegetative renewal of the Siberian phlox ( Phlox sibirica L.) in crops in the south of Central Siberia. The objectives of the study were to study the dynamics of development of the vegetative renewal of the Siberian phlox, and to determine the area of tufts formed by the spreading material during the growing season in the years of observation. According to the method of B. A. Dospekhov, in the Khakass Botanical Garden, by the method of organized repetitions, pieces of young rhizomes of a plant with one above-ground shoot were planted in 3 terms with two options (with shelter and without shelter). In the process of observation, at the beginning of the growing season, the number of shoots and the area of vegetative renewal were recorded for three years (2006-2008). It was established that: an increase in the area of turfs in the 1st year of vegetation occurred by 2.0-5.0 times, in the 2nd year - by 1.5-3.3 times, in the 3rd year - by 1.5-4.0 times. The obtained research results are reliable at the 5 % significance level. Over 3 years of vegetation, the increase in the area of turfs in the variants with the initial shelter occurred by 27.5-50.0 times, without shelter - by 50.0-128.0 times. The most active vegetative renewal occurred in plants planted at the earliest time (in early April), where the maximum value of turfs with an area of 1.1 ± 0.02 m² was obtained in the 3rd year of plant vegetation. On average, for the 1st year of vegetation in the variant with shelter, sods with an area of 0.05 m² were formed, and in the variant without shelter - 0.03 m². During the 2nd year of vegetation, in the variant with shelter, sods with an area of 0.33 m² were formed, and in the variant without shelter, 0.27 m². During the 3rd year of vegetation in the variant with shelter, sods with an area of 0.57 m² were formed, and in the variant without shelter - 0.6 m². In the arid conditions of the south of Central Siberia, for the purposes of greening and landscape construction, it is promising to use the Siberian phlox, which forms a good vegetative renewal and does not require systematic watering.

The Kayander larch ( Larix cajanderi Mayr) is the most important forest forming tree species of Chukotka, located on the northeastern border of its range. In the course of field studies in August 2021, the altitude limits of the larch distribution in the Chuvansky Ridge system, in the basin of the Ozernoe Gorlo River. In the estuary part of the valley of the Ozernoe Gorlo River has a significant array of larch forest. Between the Lednikovoe Lake and the mouth of the Ozernoe Gorlo River, at the height of the riverbed 290-350 m, the parameters of larch communities are significantly reduced. At a height of the riverbed 380 m, larch sparse woodlands are marked only by small fragments on the slopes of the southern exposure, or by single trees, often having branched stems and a widely spreading crown. On the left side of the Lednikovoe Lake basin, with a large gap in distance, at an altitude of 470-480 m, single larches of a significant age category are found among the thickets of dwarf pine ( Pinus pumila (Pall.) Regel). These trees have a height of 4-5 m and a widely spreading crown. South of Lednikovoe Lake, at a distance from the lake approx. 8 km to the south-west, at an altitude of about 660 m, we met larch only once. Here, a young solitary tree grows on a small fragment of fine earth among a stone placer covered with epilytic lichens (Lichenes ) . Its stem has a height of 1.3 m. The area we are considering is in the Ozernoe Gorlo River basin, can serve as a reference for monitoring observations of age-old changes in the altitude boundary of forest vegetation.