Динамика биометрических и углеродных показателей сосновых насаждений на залежных землях Красноярской лесостепи

Рассмотрено взаимодействие основных лесообразующих пород Сибири: ели сибирской(Picea obovataLedeb.), березы кустарниковой(Betula fruticosa Pall.), сосны обыкновенной(Pinus sylvestrisL.), осины обыкновенной(Populus tremulaL.), лиственницы сибирской(Larix sibiricaLedeb.) и сосны сибирской кедровой(кедра) (Pinus sibiricaDu Tour) с агросерой почвой. Исследования проводились в специальном многолетнем эксперименте с лесными культурами, заложенном по инициативе проф. Н. В. Орловского в 1968–1969 гг. в южной тайге на территории Кемчугской возвышенности. Выявлено, что биологические особенности и сукцессионное положение древесных пород существенно влияют на все компоненты фитоценоза. Через 45 лет наиболее резкие изменения зафиксированы под пологом раннесукцессионных хвойных (лиственница) и мелколиственных (берёза и осина) пород, тогда как позднесукцессионные породы – ель и кедр – на данном этапе существенно ограничивают развитие подчиненных ярусов. Почвенный профиль в условиях эксперимента формируется вследствие дифференциации пахотного субстрата почвообразующей породы на генетические горизонты. Влияние лесного полога на плантажированную агросерую почву происходит постепенно и усиливается по мере роста и развития культур, образования подстилочного горизонта и охватывает все свойства почвы. Активным современным почвообразованием затронут минеральный слой почвы 0–10 (13) см. Главным фактором образования почвенного профиля являются вертикальные потоки вещества и энергии, поступающие в почву в процессе нарастающей емкости и интенсивности биологического круговорота. Отмечено, что почвы под культурами в условиях многолетнего эксперимента развиваются по зональному типу. The interaction of the main forest-forming species of Siberia: Siberian spruce (Picea obovataLedeb.), bush birch (Betula fruticosaPall.), Scots pine (Pinus sylvestrisL.), aspen (Populus tremulaL.), Siberian larch (Larix sibiricaLedeb.), and Siberian stone pine (Pinus sibiricaDu Tour) with agro-gray soil is considered. The study is carried out in a special long-term experiment with forest crops, initiated by prof. N. V. Orlovskiy in 1968-69 in the southern taiga on the territory of the Kemchug Upland. It was revealed that biological characteristics and successional position of tree species significantly influence all components of the phytocenosis. The biggest changes were recorded under the canopy of early successional coniferous (larch) and small-leaved (birch and aspen) species, while late successional species – spruce and cedar – at this stage significantly limit the development of subordinate layers. Over the 45-year period of growth of forest crops, the soil profile is formed due to the differentiation of the arable substrate of the soil-forming species into genetic horizons. The influence of the forest canopy on planted agro-gray soil occurs gradually and intensifies with the growth and development of crops, the formation of a litter horizon and covers all soil properties. Active modern soil formation affects the mineral soil layer 0–10 (13) cm. Vertical flows of matter and energy entering the soil in the process of increasing capacity and intensity of the biological cycle are the main factor in the formation of the soil profile. The development of soil under forest crops under the conditions of a long-term zonal experiment was noted.

В статье освещены результаты палеоботанического изучения торфяных отложений в бассейне среднего течения р. Котуй (Северная Эвенкия). Базовым материалом для исследования стали макроостатки ископаемых растений. На основании изменения видового состава ископаемых объектов и радиоуглеродного датирования по 14С реконструирована динамика фитоценотической структуры лесных формаций за последние 6000 календарных лет. Дана количественная оценка их климатической обусловленности. В начале рассматриваемого времени в результате потепления и повышения влажности увеличивается биоразнообразие растительного покрова и формируется формация бореальных смешанных лесов с елью сибирской ( Picea obovata Ledeb.) и сосной обыкновенной ( Pinus sylvestris L . ). С нарастанием континентальности и похолодания климата биоразнообразие падает, а доминирующей формацией становится редкостойная лиственничная с лиственницей Гмелина ( Larix gmelinii(Rupr.) Rupr.). Установлена динамика границ ареалов лиственницы сибирской ( Larix sibirica Ledeb.), л. Гмелина и кедрового стланика ( Pinus pumila(Pall.) Regel.) на рубеже климатического оптимума и в позднем голоцене. The article highlights the results of a paleobotanical study of peat deposits in the basin of the middle reaches of the river Kotuy (Northern Evenkia). The macro-remains of fossil plants became the basic material for the study. Based on the change in the species composition of fossil objects and radiocarbon dating by 14C, the dynamics of the phytocenotic structure of changes in the structure of forest formations from 6000 years ago to the present is reconstructed. A quantitative assessment of their climatic conditionality is given. At the beginning of the period under consideration, because of warming and increasing humidity, the biodiversity of the vegetation cover increases and the formation of mixed forests (Siberian spruce ( Picea obovata Ledeb.), Scots pine ( Pinus sylvestris L.)) is formed. With an increase in the continentality of the climate and cooling, biodiversity decreases, and the sparse larch (Gmelin larch ( Larix gmelinii (Rupr.) Rupr.))becomes the dominant formation. The dynamics of the boundaries of the ranges of Siberian larch ( Larix sibirica Ledeb.), Gmelin larch, Siberian dwarf pine ( Pinus pumila (Pall.) Regel.) at the boundary of the climatic optimum and in the late Holocene was established.

Distribution of chemical elements in tree rings bears important information on various biogeochemical processes. In order to achieve a reliable interpretation of the information, it is necessary to know the degree of variation in the content of chemical elements both at the level of the entire species and at the level of individual trees. The research aims to determine which chemical elements have a stable distribution in the trunks of a number of conifers: Siberian spruce (Picea obovata Ledeb.), Scots pine (Pinus sylvestris L.), Siberian larch (Larix sibirica Ledeb.), and Siberian pine (Pinus sibirica Du Tour). The data for the analysis were obtained on the basis of the long-term experiment in forest growing. The experimental site was laid out in 1971–1972 in the vicinity of Krasnoyarsk by the staff of the Sukachev Institute of Forest of the Siberian Branch of the Russian Academy of Sciences. Before planting the seedlings, the soil ground was mechanically levelled, and thus, sufficiently equal growth conditions were created for all plantings. Cores with a diameter of 12 mm were sampled from three normally developing trees of each species and analyzed using modern X-ray fluorescence methods. Content relative values of elements (counts) were obtained with the Itrax Multiscanner (COX Analytical Systems). The content of elements in the tree rings was characterized by the concentration and reserve of elements. Concentration was calculated as the number of counts per 1 mm2 of the ring area; reserve was calculated as the number of counts over the entire ring area. Each of these variables was defined by the parameters of linear slope in the calendar year series and the standard deviation. The cluster analysis was performed in the 4-dimensional space of the obtained parameters. This allowed determining whether the series of element distributions from different trees and species are grouped. Three elements (Ca, Co, and P) show high stability of distribution parameters in tree rings with no regard to tree species. A number of other elements (Mn, Pb, Cl, Cr, Ni, Sr, and W) are stably grouped depending on the species. The results of the research enable to focus on the study of the elements stably distributed in the conifer trunks. For citation: Gavrikov V.L., Fertikov A.I., Sharafutdinov R.A., Vaganov E.A. Variability in Elemental Composition of Conifer Tree Rings. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 24–37. DOI: 10.37482/0536-1036-2021-6-24-37

Prediction of stand attributes of even-aged teak stands using multilevel models

The article presents the results of studies conducted in Eastern Siberia, dedicated to determining the amount of force required for detachment of Siberian larch, Scots pine and Siberian pine cones, which is one of the main indicators that determines the parameters of cone collecting machines and mechanisms for coniferous species. The pick-off force for the cones was measured at different collection times in the upper, middle, and lower parts of the crown and at different angles of pull-off force direction. The limits of these forces variability are: for the Scots pine – 23.5–48.1 N, for the Siberian larch – 27.5–42.2 N; for the Siberian pine – 3.9–7.8 N. The data obtained can serve as a basis for calculating the parameters of cone collecting mechanisation tools for the aforementioned species. When designing machines and mechanisms for collecting the coniferous trees’ cones, it is necessary to have initial data that determine the parameters of the working bodies. One of these parameters is the amount of effort required to separate the cones from the branches. The forces of detaching cones from trees in the European part of Russia were determined by a number of researchers. According to I.M. Zima with co-authors (1966), the force of detachment of cones in Scots pine (Pinus sylvestris L.) is 41.2 N. According to I.A. Lavrov (1970), pine cones can be torn off with a force of 21.1 N, and the cones of Siberian larch (Larix sibirica Ledeb) – with a force of 39.2 N. In Siberia, studies on the cones detachment were first carried out in 1970 by the laboratory of mechanization of the forest seeds collection and processing of the ASRIM forestry enterprise (Orlovsky et al., 2016). The detachment of Siberian larch, Scots pine and Siberian pine cones was studied in the forestry enterprises of the Krasnoyarsk and Altai regions and in the Republic of Tyva. The pull-off forces of Scots pine and Siberian larch cones were measured in the lower, middle, and upper parts of the crowns using dynamometers with a 0.1 N division value and with a maximum force recording device. The measurements were carried out along the branch, at an angle of 40°–50° and at an angle of 90° to the branch.

Rola zaburzeń w kształtowaniu struktury i dynamiki naturalnych lasów bukowo-jodłowo-świerkowych w Karpatach Zachodnich

The degree of space occupancy with woody plants has a certain limit associated with their biological characteristics and the level of soil fertility. The value of relative density in our country serves as a criterion for determining the intensity of thinning, while abroad the “index of forest density is used”. The purpose of the study is to substantiate the limit line “average diameter – average distance between trees” in stands of the main forest-forming species according to the data of long-term observations on permanent sample plots. The materials for the study were measurement data on permanent sample plots in the Forest experimental station of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. Sample plots were selected where the sums of the cross-sectional areas reached the maximum values once during the life of the stand, as well as where the sums of the cross-sectional areas reached the maximum twice. To verify the validity of the regression line passing through the origin, a program for calculating the equation of a straight line with a free term was used. The hypothesis of direct proportionality of the average diameter of forest stands to the average distance between trees is confirmed, while the dependence of the proportionality coefficient on the initial number of trees is not observed. In stands with maximum sums of cross-sectional areas, the ratio of the maximum average diameter to the average distance between trees is close to the constant. It serves as a good indicator of the degree of space occupancy and can be used in production and technical calculations.

It is generally agreed that preservation of forest areas can contribute strongly to the mitigation of global climate change. However, studies have demonstrated that there are still uncertainties for an accurate estimation of carbon stock particularly in the tropical forest. This study aims therefore to develop some allometric equations that can be used to estimate above-ground tree biomass and carbon partitioning between major carbon pools such as tree and litter for IITA secondary forest ecosystem. Ten permanent sample plots of 20 m × 20 m were randomly laid in the forest reserve. Diameter at breast height, total height, crown diameter and wood density were measured. Forty quadrants of 1 m × 1 m for litter fall collection were also randomly laid in four locations in each permanent sample plots. Twenty four tree species present in all the permanent sample plots were selected for destructive sampling. Mean biomass of each sampled plots were pooled together to develop allometric equations to obtain biomass and carbons were also estimated using standard method. A total of nine hundred and forty seven tree species were measured in the study area. These tree species belong to sixteen different families. Allometric equations of family level and whole stand level for estimating above-ground tree biomass were therefore developed. The best fitted allometric equations were used to predict above-ground tree biomass. Model 3 indicated the highest modelling efficiency of 0.954, 0.960 and 0.984. Therefore taking this into consideration, that model 3 was selected as the best model for predicting the above-ground tree biomass with an estimation of 17698.76 g at family level. Allometric equations of whole stand level for above-ground tree biomass indicated good correlation with H, DBH, CD and WD (0.534, 0.597, 0.751, and 0.648). Model 5, 7 and 8 were designated the highest modelling efficiency of 0.898, 0.922 and 0.948. Model 8 is selected as the best models for predicting the above-ground tree biomass with an estimate of 838036.15 g. Therefore, carbon capture per hectare of above-ground tree biomass was 368280.40 g/ha. Carbon capture per hectare of litter had 2663.259 g/ha using standard method. The distributions of the standard residual values and standard error estimate with the fitted values are adequate.

Modelling top height growth and site index using repeated laser scanning data

Pathways of forest compositional dynamics over five decades (1953–2005) were reconstructed using measurements from permanent sample plots in a long-term silviculture experiment in a central Maine mixedwood forest. The objective of this study was to elucidate the dynamics of tree species composition at the sample plot level in relation to the initial composition when the experiment was established (1953–1957) and harvest disturbance history following a wide range of even-aged and uneven-aged silvicultural treatments. Cluster analysis revealed three groupings of sample plots based on pretreatment composition and harvest disturbance history, or nine subclusters (i.e., three harvest disturbance histories nested within each pretreatment composition). From 1953 to 2005, the silvicultural treatments generated an array of compositional outcomes at the plot level. Hardwood dominance increased following a history of heavy and infrequent harvests, while northern conifer dominance was maintained where harvests were lighter and more frequent. The importance of balsam fir ( Abies balsamea (L.) Mill.) changed little across a range of harvest intensities. A ubiquitous decline in northern white-cedar ( Thuja occidentalis L.) was found among silvicultural treatments, suggesting that additional intervention may be needed to promote cedar recruitment. Plot-level compositional dynamics indicated that neighborhood-scale stand dynamics were associated with variability in harvest disturbance overlain on plot-to-plot variability in tree species composition at the time the experiment was established.

In 1972-1973, large-scale drainage of peat lands for the purposes of effective forestry was carried out on the territory of the West Dvina Peatland-Forest Station of the Institute of Forest Science of the Russian Academy of Sciences in the Tver Region [Biogeocenological ..., 1982]. Here, in the conditions of the subtaiga of European Russia, swamp forests, bog moss forest and swamps are common, formed on different types of peat − from eutrophic to oligotrophic. In 1974, a permanent sample plot was laid in the Pinetum andromedo-eriophoroso-sphagnosum on the oligotrophic bog. Repeated surveys of this sample plot were conducted in 1983 and 2023. The sample plot (SP) has the number 5-74, has an area of 0.36 ha and a rectangular shape of 36×100 m2 (Fig. 1). The long side of the SP is located parallel to the drainage ditches 35 m from them. The distance between the ditches is 106 m. The depth of the peat is about 4 m. The drainage regime corresponding to the location of SP 5-74 in the middle of the 106-meter channel is considered extensive. The peat soil was characterized by the constancy of the botanical composition of peat-forming agents up to 3.5 m and was represented by the upper magellanicum peat (Sphagnum magellanicum Brid.) with a degree of decomposition of 5-25%, deeper − sphagnum transition (Sph. girgensonii Russ.) with a decomposition rate of up to 30%. The carbon content in peat is 48-50%, the pH does not exceed 3.0, the ash content is 2-5%. High peat soil is characterized by a low volume mass (density): from 0.046 in the upper layers to 0.090 g/cm3 in the lower ones [Glukhova, 1990]. In 1974 SP 5-74 was laid in the Pinetum andromedo-eriophoroso-sphagnosum, which was characterized by Vb class of productivity and V class of age. In 1983, a more productive pine forest of the same V class of age was formed at this place, but still belonging to the Vb class of productivity: compare table 1 for 1983 M = 24.4 m3/ha, and for 1974 M =14.3 m3/ha. In 2023, the Pinetum ledoso-sphagnosum drained of the Va class of productivity and V class of age with M=50.0 m3/ha was already described at this site. The taxational characteristics of the stand by year and layer are given in table 1. Extensive drainage of Pinetum andromedo-eriophoroso-sphagnosum with Vb productivity class showed that 10 years after drainage, a more productive pine forest was formed, and 50 years later – Pinetum ledoso-sphagnosum drained with Va productivity class. Based on the taxation data, the stock of stand was calculated for three years of observations (1974, 1983, 2023), which amounted to 14.3, 24.4 and 50.0 m3/ha, respectively. To convert stand stocks into carbon stocks in the phytomass of a stand (trunk, branches, foliage, roots), a conversion coefficient was used, which, in accordance with the methodological guidelines [On approval ..., 2022] turned out to be 0.314. The analysis of carbon stocks showed that it increased 1.7 times in 10 years, and 3.5 times in 50 years. Regression analysis of these data showed a linear dependence of the carbon stock (C) on the age of extensive drainage (Adrain) over a 50-year period (Fig. 2): C = 0.2322 × Adrain + 5.0116, t/ha, where R2 = 0.99; p-value (F) = 0.064 for α = 0.05. The coefficient of determination (R2) of the regression linear equation is high, but the equation is not reliable (p-value (F) α). In the future, these data can be replenished by analyzing the increments of model trees or mathematical modeling. Over the 50-year drainage period, the average annual increase in the stock of the stand was 0.71 m3/ha and the average annual increase in the carbon stock of the phytomass of the stand was 0.24 t/ha. An analysis of the literature on drained bog pine forests of the V-Vb bonitet showed that the stock of stands, depending on the age of drainage, may generally increase, less often decrease.

The main organic carbon stocks in the predominantly boreal forests of Russia are contained in the soil pool. Quantitative estimates of soil pool carbon stocks vary considerably. This is due to the high temporal and spatial variability of the organic carbon content in soils, the lack of empirical data for a number of regions, the difference in approaches to assessing soil carbon and the density of soil horizons, the thickness of the soil layer taken into account, the inclusion of forest litter carbon stocks, the peat layer, etc. In 2020, the 1st cycle of the State Forest Inventory in Russia was completed using a selective statistical method. Forest inventory characteristics, environmental indicators and information on forest growth conditions have been obtained for 69.1 thousand permanent sample plots. The limited availability of field descriptions of soils necessitates the testing of an integrated approach to using the State Forest Inventory data in the software environment of geographic information systems in combination with open-access digital resources to assess carbon stocks in the soil pool. A methodology for quantitative assessment of carbon stocks in the forest soil pool has been developed and experimentally tested. The proposed methodology includes: 1) geo-referencing of sample plots; 2) bringing the initial data of the State Forest Inventory on soil types to a standard classification; 3) using the digital resources of the World Data Center for Soils (SoilGrids) to obtain reference average carbon stocks on the network of sample plots surveyed during the State Forest Inventory; 4) calculating the total carbon stock in the soil pool of forest lands based on the average carbon stocks of SoilGrids and areas of standard soil types based on the data of the State Forest Inventory. The experimental testing has been carried out using the Republic of Karelia as an example. The sample size has been 667 permanent sample plots. According to the results of the study, the predominant complex of soil types – illuvial-ferruginous and illuvial-humus podzols (without division), illuvial low- and high-humus podzols – covers an area of 7.28 mln ha. The total carbon stock in the 0–30 cm soil layer for the forest lands of the Republic of Karelia is estimated at 773.9 Mt C with an average of 79.1 t C/ha.

An algorithm-based approach for tree selection in continuous cover forestry

Summary The composition of Monks Wood, a 157 ha nature reserve in eastern England, in 1964–66 was compared with that in 1996 using data from 36 temporary sample plots distributed systematically across the wood and from a 70 × 35 m permanent sample plot. The overall composition of the wood changed little, but declines in the abundance of Betula pendula, and locally of other species such as Populus tremula had occurred. Both the density of tree stems and of shrub stools declined significantly between 1966 and 1996: for trees from 1469 to 611 stems per hectare, for shrubs from 235 to 177 stools per hectare. Stem basal area also increased. There were substantial changes in the ground flora: reductions in frequency of Mercurialis perennis, increases in Brachypodium sylvaticum, Carex pendula, Glechoma hederacea, Poa trivialis and Urtica dioica. The changes in the tree and shrub layer appear to be mainly a consequence of ‘internal’ factors, stand growth and self-thinning. The ground flora changes reflect a new ‘external’ factor affecting the wood, increases in deer browsing. The die-back of oak Quercus robur recorded over the last six years appears to be a recent phenomenon that needs further monitoring.

Aim Structure and floristic composition of forest regeneration (trees between 1 and 10 cm diameter at breast height (d.b.h), ≥ 1 m growth height) was described in three forest types of Amazonian white‐water forests (várzea), in order to analyse whether floristic composition of saplings is related to the successional stage of the forests, whether it differs in comparision with the mature flora, and if there exists a zonation of sapling species along the gradients of flooding and irradiation.Location Mamirauá Sustainable Development Reserve, Western Brazilian Amazon.Methods The investigated forests were of the low and the high várzea type, on an annual average flooded around 4 and 1 months, respectively. The two low‐várzea forests belonged to the secondary and to the late‐successional stage, the high‐várzea forest also to the late‐successional stage. A total of 24 circular sample plots covering 1885 m2 were installed. They were nested within three rectangular 1 ha permanent sample plots where individuals ≥ 10 cm d.b.h. were formerly inventoried. Average inundation and radiation [relative photosynthetically active radiation (rPAR)] at the forest floor was recorded in all inventoried plots. The Mean spatial Distribution Center (MDC; Ebdon, 1998) for all sapling species was calculated. Sapling species were grouped into associations with respect to their light‐demand and their location along the flood‐level gradient.Results Average flood height and average rPAR at the forest floor was highest in the secondary stage of the low várzea and lowest in the high‐várzea forest. Overall average density and basal area of the saplings averaged 2250 individuals and 2.3 m2 ha−1 in the secondary stage, 2330 individuals and 2.6 m2 ha−1 in the late‐successional stage of the low várzea and 5000 individuals and 4.8 m2 ha−1 in the high várzea. In all forest types, species richness of saplings was lower than species richness of trees ≥ 10 cm d.b.h., and amounted to 25 species in the secondary stage, to 35 species in the late‐successional stage of the low várzea and to 88 species in the high‐várzea forest. The amount of ‘immigrants’ (Bazzaz, 1991) at the sapling level increased with proceeding forest succession and amounted to 24 and 29% in the low várzea and to 31% in the high várzea. Sapling species distribution, species richness and individual density was linked to both, the gradient of flooding and the gradient of irradiation. Species richness and individual density was highest in the high várzea and decreased with increasing influence of flooding. The high várzea was predominated by pronounced shade‐tolerant sapling species, whereas in the low várzea occured both, light demanding and shade‐tolerant species groups.Main conclusions Influence of flooding seems to be the main factor triggering species composition and structure of sapling communities in várzea forests. Proceeding forest succession reduces the impact of flooding because of the biogenical induced silting up of the forested sites. However, forest succession also alters forest architecture of the overstory and such the light conditions at the sapling level. Therefore, radiation is an important factor influencing species composition of sapling communities in várzea forests.