Spruce Pine Forests Research Articles

Estimation of Carbon Stocks in Soils of Forest Ecosystems as a Basis for Monitoring the Climatically Active Substances

—The eluvozems and soddy eluvozems on two-layered deposits dominating in the soil cover of the Zvenigorod Biostation of Moscow State University, contain, on average, 65–83 t/ha of organic carbon in the organic layer and the upper meter of mineral strata. Carbon stock is minimal (59–68 t/ha) in the coarser-textured soddy eluvozem of the spruce forest and reaches 76–92 t/ha in soils of birch–spruce and pine–spruce forests. Organic layers store 3.3–5.8 t C/ha or 4–9% of the total soil organic carbon stock; the upper mineral layer (0–20 cm) stores 64–69%. Different levels and profile distribution of organic carbon in soils are determined by lithological and textural features of the soil profiles and by the nature of vegetation. The contribution of water-extractable organic carbon to the total organic carbon content in the upper mineral horizons does not exceed 1.3–1.8%; the contribution of microbial carbon is 1.7–2.4%. In acidic loamy soils, the enrichment in calcium and potassium, the cation exchange capacity, the content of exchangeable bases, and the degree of base saturation can serve as indicators of the content and stocks of organic carbon at the ecosystem level. The relationship with the content of clay fractions and oxalate-extractable Al and Fe is manifested to a lesser extent due to the similar origin and properties of soils. The variability of organic carbon stocks in soils is largely determined by its content, the influence of which decreases with depth. Accounting for spatial heterogeneity, field measurements of the soil bulk density and proportion of fine earth, and correct analytical determinations are essential components of the assessment of carbon stocks in soils of forest ecosystems as a part of the national monitoring system for carbon pools and greenhouse gas fluxes.

Estimation of Carbon Stocks in Soils of Forest Ecosystems as a Basis for Monitoring Climatically Active Substances

The eluvozems and soddy eluvozems on two-layer deposits dominating in the soil cover of the Zvenigorod biostation of Moscow State University contain, on average, 65–83 t/ha of organic carbon in the litter and a meter-deep layer of mineral strata. Carbon stocks are minimal in the soddy eluvozem of the complex spruce forest (59–68 t/ha), which is characterized by a lighter granulometric composition, and reach 76–92 t/ha in the soils of the birch–spruce and complex pine–spruce forests. At the same time, 3.3–5.8 t C/ha or 4–9% of the total organic carbon reserves are concentrated in the litter, and 64–69% in the upper mineral layer (0–20 cm). Different levels and profile distribution of organic carbon reserves in soils are determined by lithological and granulometric features and the nature of vegetation. The contribution of water-extractable organic carbon compounds to their total content in the upper mineral horizons of soils does not exceed 1.3–1.8%, microbial carbon, 1.7–2.4%. In acidic light loamy soils, the enrichment in calcium and potassium, the cation exchange capacity, the content of exchangeable bases, and the degree of saturation can serve as indicators of the content and reserves of organic carbon at the ecosystem level. The relationship with the content of finely dispersed fractions and oxalate-extractable Al and Fe is manifested to a lesser extent due to the similar origin and properties of soils. The variability of organic carbon stocks in soils is determined to the greatest extent by its content, the influence of which decreases with depth. Accounting for spatial heterogeneity, field measurements of the density and proportion of fine earth, and correct analytical determinations are essential components of the assessment of carbon stocks in soils of forest ecosystems as part of a national monitoring system for carbon pools and greenhouse gas fluxes under development.

TRANSFORMATION OF PLANT COMMUNITIES AT THE TURN OF THE PLEISTOCENE AND HOLOCENE IN THE ROSTOV LOWLAND (YAROSLAVL REGION)<a href="#FN1"><sup>1</sup></a>

The article presents the results of a multiproxy study of a sedimentary sequence located on the lacustrine-alluvial plain west of Lake Nero (Yaroslavl region). The investigated 2 m-long core made it possible to reconstruct environmental changes since the Allerød to the Late Holocene. Previously poorly studied Preboreal deposits in this area have a significant thickness in the core (0.4 m). The obtained materials help fill the gap in understanding of the vegetation history in the Rostov lowland at the turn of the Late Glacial and Holocene and during the Early Holocene. The study is based on several paleogeographic methods: spore-pollen analysis, botanical composition analysis of peat, diatom analysis, loss-on-ignition, and radiocarbon dating. It was found that after 14.3 cal. ka BP sparse spruce-birch forests were widespread, open spaces were occupied by herbaceous communities. Since 13.7 cal. ka BP, as a result of a significant cooling, the open areas expanded, sparse birch forests dominated in combination with steppe and tundra associations. About 12.1 cal. ka BP a lowland reed wetland began to form at the site. It transformed into a reed-sedge wetland after 10.9 cal. ka BP. During the interval of 12.1–11.5 cal. ka BP, the landscapes of the periglacial forest-steppe were gradually replaced by pine-birch forests. The climate was colder than today, but with the tendency to warming compared to the Late Glacial stage. Short-term cooling 11.5–11.2 cal. ka BP led to a new expansion of open herbaceous communities, but the spread of forests continued after 11.2 cal. ka BP. Starting from 9.8 cal. ka BP, the role of broadleaf species increased in the woods; mixed pine-birch forests with oak, elm, and linden dominated in the surrounding area. In the interval 7.9–5.2 cal. ka BP, climate conditions were warmer than modern ones. This led to the spread of spruce-pine forests with birch and thermophilous deciduous trees. After 5.2 cal. ka BP the vegetation cover was dominated by spruce forests with pine, birch, and broadleaf species.

Landscape structure of the territory of the district Pustynsky of the projected National Park Nizhegorodskoe Zavolzh’e

The paper presents the results of landscape differentiation of the territory of the district Pustynsky of the projected National Park Nizhegorodskoe Zavolzh’e, performed at the hierarchical level of landscape types. The researched territory is located in the broad-leaved forest subzone of the forest-steppe zone, indigenous vegetation has been preserved on its territory - broad-leaved spruce, pine, pine-spruce forests. Currently, is being completed work on the creation of the Nizhny Novgorod Region’s first national park Nizhegorodskoe Zavolzh’e, which is designed as a cluster, including five sites. The specifics of the national park’s operating mode require functional zoning of the territory, taking into account the vulnerability of natural complexes, permissible recreational loads and distribution areas of rare plant and animal species, which determines the high demand for landscape zoning schemes necessary for the effective organization of environmental and recreational activities. The article presents a scheme of landscape zoning of the territory of one of the five districts of the projected national Park – Pustynsky.

Multimillennial fire history of northern Finland along a latitude/elevation gradient

In boreal environments, wildfires are expected to decrease in frequency and/or size with latitude/elevation, mainly in response to climate, as well as fuel availability and type. Furthermore, fire frequency and biomass burned are supposed to have been higher during warm and dry periods of the Holocene (last ∼ 11,000 years). We tested these assumptions in northern Finland by using charcoal analysis to reconstruct Holocene regional fire regimes from eight lake sediment sequences sampled within four different environments in terms of elevation, latitude and vegetation type: (1) low latitude/mid elevation coniferous forests (Pinus sylvestris and Picea abies); (2) mid latitude/low elevation pine forests (Pinus sylvestris); (3) mid-high latitude/elevation transitional mixed forests (Pinus sylvestris and Betula pubescens subsp. tortuosa); and (4) high latitude/elevation birch woodlands (Betula pubescens subsp. tortuosa). As expected, fire frequency decreased with increasing latitude/elevation. Contrary to expectations, fire frequency was not significantly higher in the warm and dry mid-Holocene than in the cool and wet late Holocene, except in transitional mixed forests. Biomass burned was higher in the mid- than in the late Holocene, but only in pine and pine-spruce forests. The opposite was observed in transitional mixed forests and birch woodlands, suggesting that factors other than climate controlled fire regimes in these environments. While climate warming will likely result in more biomass burned in low latitude/elevation coniferous forests, other disturbances (such as insect outbreaks) might play a more important role in high latitude/elevation birch-pine forests and birch woodlands.

Vegetation dynamics in the Rostov lowland (Yaroslavl oblast) during the Late G lacial and Holocene based on a new pollen data

Abstract. Our reconstructions of vegetation changes are based on the results of pollen analysis that was carried out for the sedimentary sequence located on the lacustrine-alluvial terrace west of Lake Nero. To clarify our conclusions, six 14C dates were obtained and an age-depth model based on these dates was constructed. It is established that open spruce-birch forests were widespread during the Aller d and Younger Dryas. Since the Preboreal stage of the Holocene, a peat bog began to form surrounded by pine and birch forests with spruce. The Boreal stage was marked by an increased role of broad-leaved trees in the forests. During the Atlantic period, climatic conditions became warmer and spruce-pine forests with thermophilous deciduous trees started to grow. The vegetation cover of the Late Holocene (SB-SA periods) was dominated by spruce forests with pine and birch.

Paleogeographic conditions of human habitation on the Karelian coast of the White Sea in the Late-Holocene (Chupa Town, Karelia, Russia)

Bottom sediments from Lake Pervoe Starushechye, on the White Sea shore, near Korabelnaya Bay, Chupa Town, 500 m from an archaeological site, were analyzed. The aim of our studies was to determine the position of the sea shoreline, to correlate archaeological sites relative to it, to date ancient settlements, and to reconstruct the paleoclimatic conditions and habitats of ancient people. Spore and pollen, diatom, and radiocarbon (14C) analyses were done. New evidence for the time of retreat of the seashore, the isolation of Lake Pervoe Starushechye from it and the time of the possible invasion of the area by ancient people was obtained. People were shown to inhabit the area from 3970 ± 120 to 3250 ± 120 14С y.a., when the sea shoreline reached modern levels of 19–22 m. The lake was then a ~8 m deep White Sea bay, in which marine gyttja was deposited. These events are reflected in the stratigraphy of the sequence and supported by the results of diatom and spore and pollen analyses. About 3500 y.a., mean annual temperatures in North Karelia were 2°С and annual precipitation ~50 mm/year higher than modern values. Spruce and pine-spruce forests with aspen and alder patches grew on the shore. A favorable climate and exuberant vegetation attracted people. Therefore, it is at the Atlantic-Subboreal boundary that the archaeological sites located at the above altitudes could arise. The lake separated from the White Sea 3020 ± 90 14С y.a. Freshwater sapropel was deposited in the isolated lake, as indicated by the composition of diatom flora and spore and pollen spectra. The sea shoreline declined to 17–16 m. Light-coniferous pine lichen-green moss forests with light-loving oligotrophic grasses were spreading actively throughout the study area.

Spatiotemporal Modeling of Coniferous Forests Dynamics along the Southern Edge of Their Range in the Central Russian Plain

Forests with predominance of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) within the hemiboreal zone are considered as secondary communities formed under long-term human activity (logging, plowing, fires and silviculture). This study raises the question—how stable is current state of coniferous forests on the southern border of their natural distribution in the center of Eastern Europe using the example of the Moscow region (MR)? The object of the study are spruce and pine forests in different periods of Soviet and post-Soviet history within the Moscow Region (MR). The current proportion of spruce forests is 21.7%, and the proportion of pine forests is 18.5% from total forest area according to our estimates. The direction and rate of forest succession were analyzed based on current composition of populations of the main forest-forming species (spruce, pine, birch, aspen, oak, linden, and ash) based on ground-based research materials collected in 2006–2019. This allowed to develop the dynamic model (DM) of forest communities with the participation of Norway spruce and Scots pine for several decades. Assessment of the spatial distribution of coniferous communities is based on field data and spatial modeling using remote sensing data—Landsat 8 mosaic for 2020. In parallel, a retrospective model (RM) of the spatial-temporal organization of spruce and pine forests for a 30-year period was developed using two Landsat 5 mosaics. For this, nine different algorithms were tested and the best one for this task was found—random forest. Geobotanical relevés were used as a training sample combined with the 2006–2012 mosaic; the obtained spectral signatures were used for modeling based on the 1984–1990 mosaic. Thus, two multi-temporal spatial models of coniferous formations have been developed. Detailed analysis of the structure of spruce and pine forests based on field data made it possible to track trends of successional dynamics for the first time, considering the origin of communities and the ecological conditions of habitats. As a result, ideas about the viability of spruce and pine cenopopulations in different types of communities were formulated, which made possible to develop a dynamic model (DM) of changes in forest communities for future. Comparison of the areas and nature of changes in the spatial structure of coniferous formations made possible to develop the RM. Comparison of two different-time models of succession dynamics (DM and RM) makes possible to correct the main trends in the transformation of coniferous forests of natural and artificial origin under the existing regime of forestry. A set of features was identified that indicates risk factors for coniferous forests in the region. A further decrease of the spruce and pine plantations and increase of the spruce-small-leaved and deciduous formations are expected in the study area. The proportion of pine-spruce forests does not exceed 3% of the area and can be considered as the most vulnerable type of forest.

LATE GLACIAL AND HOLOCENE NATURAL ENVIRONMENT DYNAMICS AND EVOLUTION OF LAKE OKUNOZERO, SOUTH KARELIA: MICROPALAEONTOLOGICAL DATA

Bottom sediments from Lake Okunozero, located in front of Syamozero marginal formations, were analyzed to better understand the degradation conditions of the Last Glaciation in South Karelia at the Neva (Syamozero) stage and to assess the effect of climate on environmental changes. Paleogeographic reconstructions are based on the study of lake sediments using an integrated approach, which comprises spore-and-pollen, diatom and radiocarbon (14C) analyses. More evidence was obtained for the Late Glacial deposition pattern, the environmental conditions and evolution dynamics of the proglacial ice lake directly contacting the ice margin and of vegetation in that period. For the first time, Lake Glacial sediments were found to contain over 30 redeposited marine diatom alga species and varieties, not reported earlier from rock sequences of that period. The lake separated from the periglacial water body at the end of the Late Dryas. Its evolution after separation from the proto-Onega was traced, evolution stages were recognized, and more light on was shed the paleogeographic conditions in the surrounding area. The vegetation dynamics from the Allerod to the present day was reconstructed. In the Late Glacial Period the study area was occupied by tundra dwarf birch-true moss, sagebrush-wormwood periglacial-steppe and forest-tundra paleocommunities. Meadow-like tall-herb communities and birch forests with an admixture of pine appeared in the Preboreal. In the Boreal time, light-coniferous pine forests with an admixture of birch occupied the area, to be replaced in the Atlantic period by pine-spruce forests with the participation of broad-leaved species. Since the Subboreal, spruce and pine-spruce forests have prevailed in the study area. We observed that diatoms were missing from some horizons in almost every paleoclimatic period and suggested possible explanations for these gaps.

The Environment at Lake El’gygytgyn Area (Northeastern Russian Arctic) Prior to and After the Meteorite Impact at 3.58 Ma

Upper Pliocene sediments from a number of fluvial outcrops in central Chukotka, northeastern Russian Arctic, along the Enmyvaam, Mechekrynnetveem, and Chanuvenvaam Rivers, have been newly studied for pollen, non-pollen-palynomorphs and, for the first time for Pliocene sediments in Eurasia, charcoals. The sediments have survived the El’gygytgyn meteorite impact event at ∼3.58 Ma. The stratigraphy of the studied outcrops suggests that the lowermost sediments were accumulated shortly before the impact event, between ∼3.60 and 3.58 Ma. At that time, coniferous forests with spruces, pines, firs, birches, larches, and alders dominated in the area. Some relatively thermophilic broad-leaved taxa (Corylus, Carpinus, Ulmus, and Myrica) might also have grown in local forests. Summer temperatures were at least 10°C warmer than today. Charcoal concentrations and composition suggest the presence of high intensity fires. Periods of rather wet climate and soil conditions are marked by common shrubby and boggy habitats with ericaceous plants and Sphagnum, and are associated with less, and probably low-intensity surface fires with less charcoal. The impact event caused widespread fires reflected by up to 4 times higher charcoal concentrations in the sediments. The sediments found above the so-called “chaotic horizon” (sediments accumulated synchronously or very shortly after the impact event) contain late Pliocene pollen assemblages comparable to those in Lake El’gygytgyn, reflecting that pine-spruce forests with some firs, birches, larches, and alder dominated in the study area. Some thermophilic taxa might also still have grown in the area. However, the age control for the sediments above the so-called chaotic horizon is poor. The uppermost sediments from the studied sections can be attributed with certainty to the Late Pleistocene and Holocene according to their stratigraphic positions and pollen assemblages. The combined pollen and charcoal analysis allowed correlating hardly datable fluvial sediments and points to varying fire regimes in warmer-than-present climates, when forest extended further north compared to today.

Строение, состав и условия формирования четвертичных отложений в Кельтминском погребенном каньоне (юго-восток Республики Коми)

Our lithological study of the Quaternary strata in the section of the well 17843 resulted in identification of three sediments sequences of various thickness and composition. In the lower part of the well, at depths of 43.2—27 m (layers 5, 4d and 4c), the sediments were formed probably in fluvioglacial conditions. The sediments are characterized by high content of ilmenite — 7—14 %, and group of titanium minerals — 7—12 %, where concentrations of leucoxene and titanite are increased. The content of chromespinellides increases downwards from 2 to 4.4 %. In the depth interval 25.9—23.6 m (lay 4b), a dense, poorly-sorted silty clay without clastic material is exposed; its genesis is unclear. Clay is characterized by the highest amount of heavy fraction in the section — 1.91 %, and contains an abnormally high amount of magnetite — on average 31 %. The upper 22 m of the sequence (layers 4a and 3—1) are represented by alluvium — well-sorted medium-fine-grained sand with amphibole-ilmenite-garnet-epidote association of heavy minerals and increased amounts of metamorphic minerals — 7—10 %, chromespinellides — 4—6 %, and magnetite — 4—8 %. Such complex of heavy minerals in the sediments, forming the canyon, testifies to the participation of the Ural magmatic and metamorphic complexes in their formation; the supply of minerals from the Kama seems to be very problematic. Palynological analysis data obtained from layers 5, 4d, and 4b reflect a regular vegetation change of the final stages during the interglacial. Spruce-pine forests with fir, cedar, treelike and dwarf birches, alder and willow were gradually replaced by tundra plant communities, where, along with bog-tundra formations, there were xerophytic communities with wormwood Artemisia sp., Chenopodiaceae, and rare Ephedra sp.

Nest Site Selection and Nest Construction in the Willow Warbler (<i>Phylloscopus trochilus</i> L., 1758) (Sylviidae, Aves) in the Tajga Zone of Northwest Russia

Журнал принимает на русском и английском языках статьи, представляющие результаты научных исследований в различных областях теоретической и прикладной экологии. Приоритет отдается научным статьям, основанным на явно сформулированных гипотезах.

СОСТАВ И ВСТРЕЧАЕМОСТЬ ВИДОВ ТРАВЯНОГО ПОКРОВА ПОД ПОЛОГОМ 30-ЛЕТНИХ КУЛЬТУР ЕЛИ НА СРЕДНЕМ УРАЛЕ

The results of studies of the species composition of the grass cover with a tree canopy density of 0.3 - 0.7 in areas of 30-year-old spruce cultures planted in the types of herbs and green mosses spruce forest and berry spruce-pine forest were given. The materials of study showed that the species composition was more numerous in the first type of forest, 91 species of the vascular herbaceous plants belonging to 34 families, 72 genera were noted; in the second type of forest – 63 species belonging to 32 families and 57 genera. The species of the herbaceous plants of rather small frequency (their shares were 70 and 57%) prevailed. At the same time, in both types of forests 42 species of the same herbaceous plants were found. The majority of the studied herbaceous plants in both types of forests were mesophytes (77 and 95%), the proportion of hygrophytes was higher in the spruce forest of herbs and green mosses. Of the total number of species noted in these types of forests, 85 species were medicinal and 4 species were rare for the Sverd-lovsk region.

Myxomycetes of boreal forests of the Laplandskiy State Nature Biosphere Reserve (Kola Peninsula, Russia) Yuri

Northern taiga forests and subalpine plant communities of the Laplandskiy State Nature Biosphere Reserve (Kola Peninsula, Russia) were surveyed for myxomycetes. A total of 1675 specimens of myxomycete fruit bodies (sporocarps) were registered, among them 1584 records from field collections and 92 obtained from 210 moist chamber cultures of ground litter, bark of living trees, wood, and weathered dung of moose and willow ptarmigan. Most of 125 taxa (124 morphospecies and one variety) representing 34 genera were recorded only in the field (104 taxa from 32 genera), but some were exclusively obtained from moist chamber cultures (8 taxa from 5 genera). All of the recorded species are new for the Laplandskiy Reserve. Species numbers decreased among the four studied forest associations along the elevation and mositure gradient, and the Shannon index showed a similar trend: spruce forest (PICa; 84 taxa, H’=3.8), spruce-peat moss forest (PICb; 70, 3.5), dry spruce-pine forest (PIN; 62, 3.7), subalpine birch forest (SB; 30, 2.7). The estimated completeness of the survey according to the Chao1 estimator was 66%, indicating that most of the more common species should have been recovered. The trend among forest associations runs mainly parallel to diversity: PICa and PICb 83%, PIN 47%, SB 57%. The myxomycete assemblage of dry coniferous forests is the most distinctive among the three forest types and shows the highest number of indicator species. The overall degree of specialization of myxomycetes is higher for substrate type than for forest associations. Among substrate types, species diversity and richness increase from litter over bark to wood.

SEASONAL FEATURES OF METABOLISM OF WOODY GREENERY OF THE SHRUB LAYER BOREAL FORESTS

A common juniper (Juniperus Communis L.) is a representative of shrub layer of boreal forests. In this work seasonal dynamics of quantitative content of main group of juniper woody greenery extractive substances is considered. Sampling was carried out during the spring-summer-autumn period in the Arkhangelsk region outside the zone of anthropogenic impact. Forest type – blueberry, mixed spruce-pine forest stand, class of Bonita-IV. In study samples content of mineral, water-soluble, alcohol-soluble and removing by steam distillation compounds and lipids content have been determined. According to these data, content of alcohol-soluble components is from 27.1 to 33.3%. It has maximum in April which is the last month of subarctic plants resting phase. The start of growth season in May is followed by sharp decrease of alcohol-soluble components content till it is the least value. Part of the components of alcohol extracts is precipitated when cooled in the form of wax (esters of fatty acids and alcohols or sterols with an admixture of fatty acids, hydrocarbons, pigments). The maximum content (4.3%) of wax substances falls on April, the minimum (1.4%) was detected in May. Lipids content ranges from 8.6 to 12.2%. This is somewhat below in comparison with pine tree, fir and other coniferous species. The three minimums of lipids content (in May, August and December), which were extracted with petroleum ether, in juniper woody greenery are observed in annual dynamic, and one maximum (July). The content of essential oil varies slightly by season and the number (2.4–2.8%) is second only to the DZ of fir. In the group of water-soluble substances there are two highs (June and November) and a low of August. The first maximum is associated with the flow of aqueous solutions from the soil, the second corresponds to the period of phenol accumulation. The minimum is explained by the slowing down of the aspiration current through the water supply channels at the end of the summer.
 It has been established that seasonal dynamics of main group of extractive substances content of juniper woody greenery as a whole is correspond to phenological cycle.

Over- and Underyielding in Time and Space in Experiments with Mixed Stands of Scots Pine and Norway Spruce

Pine-spruce forests are one of the commonest mixed forest types in Europe and both tree species are very important for wood supply. This study summarized nine European studies with Scots pine and Norway spruce where a mixed-species stand and both monocultures were located in an experimental set-up. Overyielding (where growth of a mixed stand was greater than the average of both monocultures) was relatively common and often ranged between 0% and 30%, but could also be negative at individual study sites. Each individual site demonstrated consistent patterns of the mixing effect over different measurement periods. Transgressive overyielding (where the mixed-species stand was more productive than either of the monocultures) was found at three study sites, while a monoculture was more productive on the other sites. Large variation between study sites indicated that the existing experiments do not fully represent the extensive region where this mixed pine-spruce forest can occur. Pooled increment data displayed a negative influence of latitude and stand age on the mixing effect of those tree species in forests younger than 70 years.

Verification of a One-Dimensional Model of $$\hbox {CO}_{2}$$ CO 2 Atmospheric Transport Inside and Above a Forest Canopy Using Observations at the Norunda Research Station

A model of (Formula presented.) atmospheric transport in vegetated canopies is tested against measurements of the flow, as well as (Formula presented.) concentrations at the Norunda research station located inside a mixed pine–spruce forest. We present the results of simulations of wind-speed profiles and (Formula presented.) concentrations inside and above the forest canopy with a one-dimensional model of profiles of the turbulent diffusion coefficient above the canopy accounting for the influence of the roughness sub-layer on turbulent mixing according to Harman and Finnigan (Boundary-Layer Meteorol 129:323–351, 2008; hereafter HF08). Different modelling approaches are used to define the turbulent exchange coefficients for momentum and concentration inside the canopy: (1) the modified HF08 theory—numerical solution of the momentum and concentration equations with a non-constant distribution of leaf area per unit volume; (2) empirical parametrization of the turbulent diffusion coefficient using empirical data concerning the vertical profiles of the Lagrangian time scale and root-mean-square deviation of the vertical velocity component. For neutral, daytime conditions, the second-order turbulence model is also used. The flexibility of the empirical model enables the best fit of the simulated (Formula presented.) concentrations inside the canopy to the observations, with the results of simulations for daytime conditions inside the canopy layer only successful provided the respiration fluxes are properly considered. The application of the developed model for radiocarbon atmospheric transport released in the form of (Formula presented.) is presented and discussed. (Less)

Structure Formation of Forest Tree Species Coenopopulations During Post-Fire Recovery of Northern Taiga Forest

The goal of this study was to compare the coenopopulation structure of two main stand-forming tree species of European northern taiga forest – Picea obovata Ledeb. and Pinus sylvestris L. at different stages of post-fire successions. Investigations were carried out in the Kola Peninsula (67°30ʹ–68°10ʹ N, 33°57ʹ–34°21ʹ E) in Siberian spruce forest of the true moss site type with fire age of 82 and 146, Scots pine forest of the lichen-true moss site type with a similar fire age (83 and 155), and in mixed pine-spruce forest of the true moss site type with fire age of 376. Five 0.1–0.2-ha permanent sample plots were surveyed. In order to register living tree individuals > 0.1 m high, the sample plots were divided into 5 x 5 m squares. Tree individuals 1 yr.) were sampled from 40–100 1x1 m squares. To analyze the age and size distributions we chose three key parameters: range of values, skewness and kurtosis. The vitality of the trees was determined on the basis of relative crown density, using a five-category classification: I – healthy individuals, II – moderately weak individuals, III – very weak individuals, IV – declining individuals, V – dead individuals. According to our data, Picea obovata and Pinus sylvestris showed similar patterns in the formation of the age, size and vitality structure of the coenopopulations during post-fire succession despite the differences in biological and ecological properties. Hence, there exist common mechanisms of coenopopulation structure transformation, based on the laws of competition among tree individuals within a population and coenotic regulation of regeneration processes. The established structural differences are not significant and mostly manifest themselves during the first half of the succession. The distinctive feature of pine coenopopulations is discontinuity of the age and diameter class distribution over a period from ~100–150 to at least 400–500 yrs. after a fire. At later stages of a post-fire succession (>350 yrs. after the fire) one observes a convergence of the age, size and vitality structure of coenopopulations of the two species. This result can be regarded as evidence of uniformity of the main tree species structural organization in subclimax and climax northern taiga forest.

Фітоценотична структура лісових угруповань за участю сосни звичайної (Pinus sylvestris l.) в Українських Карпатах

На закладених постійних пробних площах деревостанів сосни звичайної проведено детальні геоботанічні описи. Для всіх виявлених видів рослин встановлено показники домінування та величини проективного вкриття. Встановлено основні риси поширення сосни звичайної та виявлено, що у межах одного типу лісорослинних умов формується кілька різних за складом та структурою фітоценозів за участю Pinus sylvestris. У результаті геоботанічних досліджень осередків зростання Pinus sylvestris в Українських Карпатах виявлено 30 угруповань з участю сосни звичайної різного складу та структури. Досліджено фітоценотичну структуру лісів з участю сосни звичайної (Pinus sylvestris L.) на основі домінантної класифікації рослинності та укладено їх класифікаційну схему. Відповідно до побудованої схеми, всі ліси за участю Pinus sylvestris поділено на три блоки: чисті соснові ліси, соснові ліси з домішкою Picea abies та соснові ліси з домішкою Betula pendula. Встановлено, що ліси за участю сосни звичайної в Українських Карпатах мають полігенетичне походження, оскільки мають значне типологічне, ценотичне та біотичне різноманіття.

Input and migration of dissolved organic carbon in soils of forest ecosystems in the subzone of deciduous–coniferous forests

The results of four-year monitoring of natural waters in forest ecosystems of the Zvenigorod Biological Station (Moscow State University, Moscow oblast) show regular changes in the concentrations and fluxes of dissolved organic carbon (DOC) within the atmospheric precipitation–throughfall–soil waters system. Precipitation passing through the tree canopy is enriched with DOC (2–3 and 9–24 mg/L). The average carbon concentration in soil waters reaches 100–110 mg/L in complex spruce and pine–spruce forests and does not exceed 40–60 mg/L in spruce–birch forests.