Post-agricultural Lands Research Articles

Wood Quality of Pendulate Oak on Post-Agricultural Land: A Case Study Based on Physico-Mechanical and Anatomical Properties

Oak is one of the most economically important hardwood tree species in Europe, and its prevalence will increase due to progressing global climate change, according to predictive models. With the increasing demand for timber and with the need for a balance between carbon emissions and sequestration, it is essential to address the afforestation of agricultural land. Therefore, this research aimed to investigate the physico-mechanical properties and anatomical structure of pendulate oak (Quercus robur L.) wood—specifically focusing on the trunk’s cross-section—in post-agricultural areas compared with the forest land in the western part of Poland. Wood density, bending strength, modulus of elasticity, and other parameters were analyzed from 1626 wood samples. The analysis of physico-mechanical properties reveals that, historically, agricultural land use has an almost negligible impact on wood quality. Despite significant differences in small vessel diameter and fiber length favoring trees from post-agricultural land, the physico-mechanical properties remain consistent. Large vessel measurements show comparable diameter and length in both land types. These findings suggest that post-agricultural land can serve as an effective alternative for high-quality pendulate oak wood production for industrial purposes. However, wood from post-agricultural land may exhibit a decrease in modulus of rupture by over 30% and potentially lower density above the trunk’s halfway point. This observation hints at the fact that oak trees in post-agricultural areas could be cultivated in shorter rotation periods compared to forest land.

Сосновые (Pinus sylvestris) леса и редколесья Северо-Западного Приладожья

Сосновые (Pinus sylvestris) леса и редколесья Северо-Западного Приладожья

Organic Inputs Positively Alter the Bacteriome of Post-Agricultural Soils

Agriculture can degrade soils and reduce microbial diversity. The reduction in microbial diversity of degraded soils is due to their long-term agricultural use. In most cases, such areas are afforested but rarely succeed in converting them into first-generation pine forests without adequately revitalizing the soils and restoring the natural relationships characteristic of forest habitats. This is possible thanks to the positive changes in soil biodiversity. To facilitate and enhance this phenomenon in the present experiment, various forms of organic matter were added to the soil: pine bark compost scattered on the soil surface (BCS) or placed under the roots of the seedlings at planting (BCR), woody debris (WW) and sawdust (S), while the control plot was not treated. The studies started in 2001 on two experimental plots, a poorer one in Bielsk and a more fertile one in Czarne Człuchowskie (eastern and northern Poland, respectively). The following year, 2-year-old pine seedlings (Pinus sylvestris L.) were planted on the plots. After 20 years, the physicochemical properties of the soil and its microbial composition were determined and compared with the control. The results encourage the use of organic matter for established pine forest crops on post-agricultural land for revitalization: C, N, and P content increased both in the organic layer and in the topsoil (up to 40 cm), where most fine roots are located. The total content of exchangeable base cations (Ca, Mg, K) and the sorption capacity of the soils (a measure of the ion binding capacity of the soil) also improved. The genetic analyses carried out using the molecular method (NGS) showed positive changes in the composition of the soil microbiome. Compared to poorer soil conditions in richer habitats, the number of taxa increases when organic matter is added, leading to significant qualitative changes in the bacteriome. The addition of organic material from the forest had a positive effect on the bacterial communities, which in turn accelerated the changes in the diversity of bacteriomes characteristic of agricultural soils and brought them closer to the forest ecosystem. The organic horizon was restored, and at the same time, the biodiversity of the soil microbiome increased, which is important for the health and sustainability of pine stands on formerly agricultural land.

Organic carbon accumulation and microbial activities in arable soils after abandonment: A chronosequence study

Increased plant carbon (C) input into the soils after cropland abandonment results in not only C accumulation, but also higher microbial activities and consequently faster organic matter decomposition. We investigated the link between soil C accumulation and microbial properties in a chronosequence (0–65 years) of post-agricultural self-restoration of Luvisols - the dominating soil type worldwide. Microbial biomass carbon (MBC) and enzyme activities increased in the top soil (0–20 cm) during the 37-year period of self-restoration. Accumulation of microbial biomass was faster than of soil organic C at earlier stages of self-restoration (0–22 years) because of the fast microbial growth induced by labile litter components. The response of microbial activity was more sensitive to land use changes compared to that of soil organic C. Activities of enzymes responsible for C cycle increased more than that of nitrogen (N) and phosphorus (P) cycles at least up to 37 years after abandonment, indicating microbial adaptations to high input of litter with wide C/N and C/P ratios. Similarly, β-xylosidase was the solely enzyme which reached the activity similar to secondary forest soils after 65 years, due to the accumulation of recalcitrant C in litter with cropland abandonment age. The increased C demand was caused by the higher bacterial portion in soil microbial community (based on PLFA composition), which in turn, resulted in a lower microbial biomass C/N ratio. Enzyme stoichiometry revealed that microorganisms were limited by C and N in the topsoil during the self-restoration up to 37 years. Overall, the quantity and quality of plant C inputs, which changed with post-agricultural land restoration, regulated the microbial activity and enzyme production, offering a profound comprehension of ecosystem succession.

Approaches to the Development of Beekeeping on Post-Agricultural Lands in the North-West Federal District of the Russian Federation

Approaches to sustainable development of food production and agriculture are being considered, taking into account ecological, social, and economic aspects. Special attention is paid to the development of beekeeping on post-agricultural lands in the North-West Federal District of Russia and its potential in solving the problems raised in the General Assembly of the United Nations on sustainable development and the Strategy for Improving the Quality of Food Products in the Russian Federation until 2030. Developing beekeeping is an important factor in the sustainable development of food production and agriculture, contributing to regional development and solving the problems raised in the General Assembly of the United Nations on sustainable development. In our opinion, the development of beekeeping and related industries on abandoned agricultural lands can solve many problems at the regional, national, and global levels. These problems are related to sustainable deve lopment, ensuring food security, environmental sustainability, and social issues.

Addition of Organic Matter to Pine Plantations on Agricultural Land Positively Alters the Mycobiome of Agricultural Soils

Afforestation of former agricultural land poses a real challenge for foresters because soil life is often severely limited by the loss of natural soil fungal diversity. In addition, former agricultural soils have low levels of fungal species typical of forest soils, which have a unique microbiome that plays a protective role (antagonists, plant growth promoters, mycorrhizal fungi, etc.). This study aimed to determine the effect of using organic material in the form of bark compost, wood waste, and sawdust to improve the soil mycobiome of soils that have been damaged by their agricultural use. This study used experimental plots established 20 years ago, and we compared the biodiversity of the treated soils with that of the control soils by analysing soil samples with powerful molecular methods. Next-generation sequencing analysis of DNA extracted from soil samples and subsequent analysis of their species composition and biodiversity showed that the mycobiome of soil fungi has been altered by the addition of various forms of organic material. The proportion of fungi belonging to the Ascomycota decreased in favour of species from the Basidiomycota and Mucoromycota. The dominant fungal groups in the soil of the control area were Sagenomella, Wilcoxina, Oidiodendron, Meliniomyces, and Penicillium. Enrichment with organic matter by adding bark compost under the roots led to an increase in Penicillium, Inocybe, and Amphinema. The application of bark compost on the surface led to an increase in the dominance of Inocybe fungi in the soil. The mycobiome of the plant to which woody debris was applied was characterised by a marked dominance of fungi of the genera Russula, Oidiodendron, and Penicillium. Similar ratios were found in the plant to which sawdust was applied, where the fungi Meliniomyces, Penicillium, Oidiodendron, and Russula dominated. A comparative analysis of fungal diversity with the Shannon diversity index showed that the most diverse fungal communities were found in the sawdust plant (6.56), while the control sample (a soil sample from an agricultural area where no organic material was applied) had an index of 5.71. After the treatments, more potential antagonists against pine pathogens and mycorrhizal fungi were found to form beneficial symbiotic relationships with them. In our opinion, the results of this study show that it is worthwhile to introduce different forms of organic matter to post-agricultural land to improve soil biodiversity and mycorrhizal associations of pine roots with fungi to ensure the sustainability of the first generation of forests created.

Зміна біотичних властивостей ґрунтів унаслідок сильватизації колишніх сільськогосподарських угідь (Сколівські Бескиди, Українські Карпати)

The article deals with an impact of the former agriculture land abandonment on biotic properties of soils. In order to better comprehend the processes of spontaneous reforestation (sylvatisation) in a mountain region (the Pohartsi boundary, Koziova village, Stryi district, Lviv regionthe (Skolivski Beskydy physiographic region, the Ukrainian Carpathians) four study plots were selected representing the successional sequence: forest → pasture → hay meadow → arable lands. The study revealed that indicators of microbiological activity is positively affected by the forest floor presence. A zone of the highest soil biotic activity coincides with the limits of the humus horizon Н. Getting deeper into soil profile microbiological activity falls manifold due to changes in physical, hydrophysical and physical-chemical soil properties. In the pasture lands that were least affected by the past agricultural activities, we found both increase and decrease in soil biotic properties. This is foremost caused by the environmental changes. Absence of the forest floor, as a major nutrient source, leads to the 30% decrease in the biomass microorganisms while soil pH shift from a largely to moderately acidic reaction causes 1,5-times higher catalase activity. The latter was the highest in the former pasture lands among all study plots and was assessed as “moderate”. Increase in the urease activity was documented, as well. However its highest values were measured in upper soil horizons of both past and present arable lands. Such an increase of the urease activity is caused by application of organic fertilizers. Despite slightly acidic reaction of the soil water extract from upper horizons of ploughed-up soils the catalase activity here decreases up to 2–2.5 times. This is caused by deterioration of hydric and aeration properties of soils due to their compaction. We noted manifold decrease in the С-СО2 production, as well. The most optimal soil parameters were characteristic for the hay meadow plot despite being significantly affected by anthropogenic activities while the succession of ‘arable lands → pasture → hay meadow’ took a path. Similar moderate soil biotic activity was distinguished for the former pasture land plots. This indicates on the self-restoration and self-regulation capacities of natural ecosystems in the region. We concluded that major indicators of soil biotic activity in the past arable lands are the urease activity, microbial biomass, and soil respiration. The catalase activity makes an additional value for soil degradation assessment of the post-agricultural land uses.

Mycobiome of Post-Agricultural Soils 20 Years after Application of Organic Substrates and Planting of Pine Seedlings

A 20-year study of a pine stand on post-agricultural land showed that woody debris in the form of organic matter can be successfully used to restore symbiotic mycorrhizal communities, as is the case with forest soils. Woody substrates restored organic matter in soils altered by long agricultural use and had a positive effect on the composition of mycobiota antagonistic to pathogens, especially to Heterobasidion annosum, the causal agent of the dangerous disease root and stump rot of many forest tree species, including stands of Pinus sylvestris (L.). In a study that started in 2001 in the forest district of Czarne Człuchowskie (northern Poland), the following organic materials were used: wood residues (W), sawdust (S), bark compost (B), and compost applied to the root zone during planting (G). The organic materials were spread in the form of mulch over the entire area during planting. After twenty years, it was found that the substrates used provided suitable growth conditions for mycobiome useful for pines. The addition of organic matter did not change the alpha biodiversity of the soil, but in the long term led to significant changes in the composition of mycobiota (beta biodiversity). The changes in the soil after the addition of organic material naturally accelerated the formation of the forest habitat. A number of fungi evolved that degraded added lignin and cellulose while being antagonists of H. annosum and other pine pathogens. In particular, the well-known hyperpathogens of the genus Trichoderma played an important role by promoting resistance of the soil environment to pathogens. Soil enrichment by bark compost and wood residues increased the relative abundance of Trichoderma more than fourfold.Mycorrhizal fungi became dominant in soil enriched with organic matter. After enriching the soil with bark compost, the relative abundance of Amphinema and Inocybe increased to 5%. The relative abundance of Russula in soil enriched with wood residues and sawdust increased to 9% and 5%, respectively. Mycorrhizal fungi, e.g., of the genus Ąmanita, Rusula, which formed root mycorrhizae, not only increased the root receiving area many times over, but also protected the roots (mechanically and chemically from pathogens). Altogether, the observed positive changes increase the chances that the first generation of pines will survive on the ground.

Usage PlanetScope Images and LiDAR Point Clouds for Characterizing the Forest Succession Process in Post-Agricultural Areas

The paper investigates using PlanetScope satellite images together with LiDAR data for automation of land use/cover (LULC) mapping and 3D vegetation characteristics in the aspect of mapping and monitoring of the secondary forest succession areas. The study was performed for the tested area in the Biskupice district (South of Poland), where a forest succession occurs on post-agricultural lands. The research area was parcels where the forest overgrowing process was identified. It was verified whether the image processing allows for reliable LULC classification as an identification forest succession area. The PlanetScope classification showed forested areas as 62.77 ha (44.91% of the analyzed area). The overall accuracy of the image classification was 96.40% The airborne laser scanning (ALS) point clouds were used for deriving detailed information about the forest succession process. The precise vegetation parameters i.e., height and canopy cover were determined and presented as raster maps, histograms, or profiles.

Soil Environment and Fauna Communities in Europe after Afforestation of Post-Agricultural Lands—A Review

Afforestation can make an important contribution mitigating the effects of changing climate and provide structural and functional benefits. Afforestation also provides challenges for forest managers connected with past land-use history; therefore, there is an urgent need to summarize knowledge about such habitats and point out the gaps in knowledge for planning future studies. Although post-agricultural forests cover a large forest area in Europe, our understanding of the mechanisms governing the below-ground environment is still poor, especially when soil fauna is considered. In this study, we revised knowledge about the soil environment and the response of soil fauna to afforestation on former agricultural lands located in Europe based on research articles from the ISI Web of Science database. Data came from various but distinct locations, compared forests with different types of agricultural lands, and presented previous knowledge about soil chemistry and accompanying soil fauna communities. Finally, we selected 15 studies, investigating soil fauna communities on post-agricultural lands. The meta-analysis was based on response ratio (R) for available data, although in many cases the data were incomplete. Results indicated that post-agricultural forests differ from arable lands in reference to soil pH, but not for soil organic matter and carbon content. Different soil animal groups were represented by a similar number of studies: microfauna (seven studies) and mesofauna (nine), whereas macrofauna were represented by five studies. Meta-analysis revealed that the response of soil fauna to afforestation differed between soil fauna size classes. Additionally, in total, 18 tree species, 12 soil types, and 20 soil parameters were provided in the literature but only a few of them were presented in a single study. Future studies should include the impact of microclimate, detailed stand characteristics and soil conditions, which could help to clearly describe the impact of certain tree species growing on certain soil types. In future soil fauna ecological studies, the data should include mean values, standard deviation (SD) and/or standard effort of means (SE) for abundance, species richness, diversity indices and number of collected samples. Providing the above mentioned information will give the broad audience the opportunity to include data in future comparative analyses.

Loss in macronutrient pools in bilberry and lingonberry in mesic Scots pine forests after Northern red oak introduction

Forest transformation from coniferous monocultures to mixed stands is being promoted worldwide, including the introduction of fast-growing broadleaved tree species within native stands. Here, we studied how enrichment of temperate European Scots pine (Pinus sylvestris) forest by North-American northern red oak Quercus rubra impacted macronutrient concentrations in two long-lived and dominant components of the forest understory: bilberry Vaccinium myrtillus and lingonberry V. vitis-idaea. Study sites were located in forest complexes (central Poland) which occupy continuously reforested lands (hereafter ancient forests) as well as post-agricultural lands (recent forests), all suitable for mesic pine forests. Samples of bilberry and lingonberry leaves, stems, and fruits were collected in pine stands and in adjacent Scots pine-red oak stands, in both ancient and recent forests. Concentrations of macronutrients (C, N, P, K, Ca, S, and Mg) in aboveground biomass components were analysed using standardized chemical procedures. The study revealed intra- and interspecific (bilberry vs. lingonberry) differences in concentrations of all nutrients in leaves, stems, and fruits, except for invariable C concentrations. Macronutrient accumulations in plants were decreased by land-use discontinuity and favoured by enrichment of tree stands by Q. rubra. The estimated macronutrient pools were much higher for V. myrtillus than V. vitis-idaea in all forest types studied. They were lower in forests enriched with Q. rubra, both ancient (up to 25.5% for bilberry and 99.9% for lingonberry) and recent (46.9% and 99.9%, respectively), as well as in recent pine forest (46.6% and 81.1%, respectively) than in ancient pine forest. Higher K and S pools (39.3% and 6.5%, respectively) noted for bilberry in an ancient forest with Q. rubra were exceptions. Despite more effective accumulations of elements at the species level, macronutrient pools of Vaccinium myrtillus and V. vitis-idaea decreased significantly in the presence of introduced Q. rubra due to negative impacts of this broadleaved tree on bilberry and lingonberry cover and biomass. Therefore, the limitation of alien Q. rubra planting in sites of mesic pine forest with the abundant occurrence of V. myrtillus and/or V. vitis-idaea is recommended.Graphic abstract

Introduction of native tree species into degraded Cerrado vegetation

Experimental restoration using tree seedlings is a common strategy for accelerating succession on degraded post-agricultural land formerly occupied by Cerrado vegetation. Seedling growth in degraded tropical lands is constrained by various factors. The goal of this study was to evaluate the seedling growth and survival of seven native tree species used to accelerate forest recovery in a gully area with stressful environmental conditions. The experimental design involved fenced and unfenced blocks, presence and absence of fertilization and use of an adhesive to prevent ant herbivory (four treatments with four replicates). Seedlings were planted in December 2006 and collection of data on seedling basal diameter, height, mortality and herbivory started on January 24th 2007 and continued every three months, until final data collection on January 31st 2009 (9 measurement dates). Overall seedling survival was 38 % and protecting seedlings did not influence growth, but seedlings grew faster in response to the addition of fertilizer containing N, P and K. The use of the adhesive Tanglefoot to exclude leaf cutter ants had no influence on growth. Fencing reduced seedling mortality, but combining fencing with Tanglefoot did not. Nutrient availability limits seedling growth and survival in the gully. Direct planting of seedlings of native trees may accelerate succession in degraded Cerrado lands subject to interventions that overcome constraints on seedling growth and survival.

Fill-up for the forest

Restoration Ecology The restoration of degraded and disturbed habitats has become a major focus of applied ecology because of the benefits it brings to ecosystem functioning and biodiversity. Cole and Zahawi show how nutrients from agricultural waste can contribute to the recovery of tropical forest on postagricultural land. In an experiment in Costa Rica, a 0.5-meter-deep layer of coffee pulp applied to the land raised nutrient levels and inhibited the growth of ground cover, especially of pasture grasses. This input promoted a succession of forest trees and shrubs, which reached substantially greater biomass and canopy height after 2 years than vegetation in a control plot. Ecol. Solut. Evid. 2 , e12054 (2021).

The impact of revitalization treatments on biological activity of soil under afforestation on post-agricultural land

In Poland, afforestation is usually carried out on the weakest soils, excluded from agricultural use and wasteland, i.e. post-agricultural land. A characteristic feature of such habitat is poor-quality soil, relatively high content of nutrients for trees, particularly nitrogen, as well as a low level of humus. This is important for the quality of microbiological processes occurring in post-agricultural soils. Restitution of the forest in such a habitat requires the use of various revitalisation treatments for improving soil quality and increasing biological activity and soil fertility. This article presents the results of a long-term experiment on the effectiveness of various revitalisation treatments (zoo- and phytomelioration) on afforested post-agricultural lands after more than 30 years from their application in pine forests in north-western Poland. These treatments consisted of introducing additional organic matter into the soil in the form of bark and sawdust, sowing lupine and introducing soil fauna. The comparative area for afforestation on post-agricultural soils in the presented experiment was the area of forest soils, located in the same habitat, in a pine stand, at the same time. Biological activity of soil was measured with the activity of soil enzymes dehydrogenases and acid phosphatase, the biomass of microorganisms was measured and the content of total dissolved carbon and nitrogen was also determined.

The Wood of Scots Pine (Pinus sylvestris L.) from Post-Agricultural Lands Has Suitable Properties for the Timber Industry

Scots pine (Pinus sylvestris L.) is a widespread species throughout Europe and at the same time is dominant in Polish forests and of key importance in the wood industry. Pine stands are subjected to numerous environmental stresses, and one of them is the different physico-chemical and biological properties of post-agricultural soils compared to forest soils, which may affect the properties of the resulting wood and its industrial suitability. The research material taken at the height of 1.3 m from tree trunks (breast height diameter, dbh) in the form of sections and discs was collected in an 80-year-old pine stand from four plots, representing former agricultural and ancient forest land, and two types of habitats: fresh coniferous forest and fresh mixed coniferous forest. The forest habitat trophy had a decisive impact on the dendrometric characteristics and properties of pine wood (density, modulus of elasticity, bending strength, and compressive strength along the tracheids). The history of soil use (post-agricultural or forestry) did not affect the analyzed pine wood properties. Regardless of the forest habitat type and soil type history, pine wood at the dbh height showed a variability of features typical of century-old cultivated stands. Individual pine trunks were characterized by significant individual variability.

Automated Land Cover Change Detection and Forest Succession Monitoring Using LiDAR Point Clouds and GIS Analyses

This paper investigates the possibility of applying light detection and ranging (LiDAR) point clouds and geographic information system (GIS) analyses for land use and land cover (LULC) change detection, mainly with a view to monitoring uncontrolled forest succession occurring on postagricultural lands. The research was conducted in a part of the administrative district of Milicz (in the central-west area of Poland). The areas of interest were parcels in which agricultural use has been abandoned and forest succession processes have progressed. The airborne laser scanning (ALS) data (acquired in 2007, 2012, and 2015) revealed detailed changes in land cover as a result of the progression in the forest succession process. Using the ALS data, the LULC changes and the progress of secondary forest succession are shown, and the vegetation parameters (LiDAR metrics) are presented.

Seemingly Unrelated Mixed-Effects Biomass Models for Young Silver Birch Stands on Post-Agricultural Lands

Secondary succession that occurs on abandoned farmlands is an important source of biomass carbon stocks. Both direct and indirect tree biomass estimation methods are applied on forest lands. Using empirical data from 148 uprooted trees, we developed a seemingly unrelated mixed-effects models system for the young silver birch that grows on post agricultural lands in central Poland. Tree height, biomass of stem, branches, foliage, and roots are used as dependent variables; the diameter at breast height is used as the independent variable. During model elaboration we used restricted cubic spline: 5 knots at the quantiles (0.05, 0.275, 0.5, 0.725, and 0.95) of diameter at breast height provided sufficiently flexible curves for all biomass components. In this study, we demonstrate the use of the model system through cross-model calibration of the biomass component model using tree height measured from 0, 2, 3, and 4 available extreme trees feature in the plot in question. A different number of extreme trees were measured for final model system and our results indicated that for all analyzed components, random-effect predictions are characterized by higher accuracy than fixed-effects predictions.

Mixed-effects generalized height–diameter model for young silver birch stands on post-agricultural lands

The purpose of creating regression equations is often to predict unmeasured features based upon more easily obtainable ones. Species-specific height–diameter (H–D) models of trees are an example of this situation and can be defined as either simple or generalized. Simple H–D models express height as a function of tree diameter at the breast height. They are easily applicable without additional measurement but do not take properly into account the variability in H-D relationship between stands. Meanwhile, generalized models also include stand-level predictors. The H-D data sets are often characterized by a grouped structure. The mixed-effects modeling approach is a mainstream method employed for these types of forestry data. In this study, we created a mixed-effects generalized H–D model for young silver birch stands on post-agricultural lands in central Poland. This model was chosen from among 11 simple nonlinear models based on the goodness of fit and residual behavior. We accounted for two stand-level predictors that did not require additional measurements beyond tree diameter at the breast height: quadratic mean diameter at the breast height and basal area. Fixed- and random-effect predictions were then calculated to illustrate that increases in the number of measured trees improves height predictions. Moreover, the gain in predictive power is the largest if extreme trees (i.e., from the extrema of the diameter range) are used for random-effect prediction.

Growth of broadleaved species on post-agricultural lands introduced during the process of stand conversion with a use of artificial gaps

Abstract This paper presents results on the restoration of Scots pine stands established on post-agricultural lands undergoing conversion into mixed stands. Sessile oak (Quercus petraea), common beech (Fagus sylvatica) and small-leaved lime (Tilia cordata) seedlings were planted in artificially created gaps (0.02 ha to 0.05 ha each) cut in six experimental plots (Forest Districts: Bielsk, Krynki, Sobibór, Dobieszyn, Skrwilno and Łupawa) located in 20–25-years-old pine stands. The experimental plots were spread across northern, central and eastern Poland and affected by root-rot fungus (Heterobasidion annosum). Nine years after planting, the number of individual trees and shrub species, their height sum and average height were calculated for fenced artificial gaps (LSO) as well as non-fenced artificial gaps (LSN) and compared to natural gaps (LN) and non-disturbed neighboring stands (D). Results were calculated separately for the planted species (oak, lime and beech) but combined for all other species. The results indicate satisfactory restoration in all of the investigated plots except in Krynki, which is located in a relatively poor site. Significant differences appeared between height sum as well as average height of planted species in fenced compared to non-fenced gaps. Furthermore, in both, natural and artificial gaps, the species composition of the young generation was enriched with natural regeneration of pioneer species, mainly silver birch (Betula pendula), rowan (Sorbus aucuparia) and aspen (Populus tremula).

Soil Organic Carbon Accumulation in Post-Agricultural Soils under the Influence Birch Stands

The aim of this study was to demonstrate the effects birch renewal on the soil organic carbon accumulation and on dehydrogenase activity. We selected 12 research plots with birch stands of different ages (1–4 years, 5–8 years, 9–12 years, and 13–17 years) to determine soil texture, pH, total carbon and nitrogen levels, and base cation content. The total organic carbon stock was calculated for the soil profiles. Additionally, dehydrogenase activity was determined. Naturally regenerated birch stands on post-agricultural land facilitated carbon accumulation. Based on our results, dehydrogenase activity is useful in assessing the condition of post-agricultural soils, and its determination allowed for us to assess the processes occurring in post-agricultural soils that are associated with the formation and carbon distribution.