Stand Composition, Tree-Related Microhabitats and Birds—A Network of Relationships in a Managed Forest

Forest ecosystems contain many tree-related microhabitats (TreMs), which are used by various groups of organisms. Birds use TreMs for shelter, foraging and breeding. The abundance and variability of TreMs is related to tree stand composition and age. Over the last few centuries there has been a drastic decline in the structural and biological diversity of temperate forests over large areas of the Northern Hemisphere. These changes have reduced the diversity and quantity of TreMs. In this study we showed the relationships between stand composition, the abundance of TreMs, and the species richness of birds in a managed forest. We focused on TreMs that are important to birds: woodpecker breeding cavities, rot holes, dead branches, broken treetops, and perennial polypores. Our study was performed in a managed lowland temperate forest. In 94 plots (10 ha each) we made bird surveys and inventoried the stand composition and TreMs. Our results show that the tree stand composition of a managed forest affects the abundance of TreMs. The share of deciduous trees in the stand favors the occurrence of such TreMs as dead branches, rot holes and perennial polypores. The overall richness of bird species and the species richness of primary cavity nesters depended on the total basal area of oak, hornbeam and birch, whereas the species richness of secondary cavity nesters increased with the total basal area of birch and oak.

Mixed pine and spruce stands in the Luga-Volkhov and Valdai-Tikhvin landscape districts of the Leningrad Region

Pine- and spruce-dominatedmixed stands occupy a substantial part of the forested area. Depending on soil and hydrological conditions of different landscapes, stands of different forest types and tree stand composition dominate. Modern forestry is focused on growing monodominant stands, but it is worth noting that mixed stands have higher productivity and stability. This work is devoted to identifying the patterns of distribution of mixed stands by forest type in different geographic landscapes. For the study, two landscape districts of the Leningrad Region (Valdaysko-Tikhvinsky and Luzhsko-Volkhovsky) with landscape mosaics of different structure were selected. The dominant forest types and types of mixed forest stands were determined by summing the areas of each plant association. To carry out the calculations, data of the state forest inventory of the Leningrad Region were used. In the course of this study, it was found that blueberry forest type was the most common forest type in mixed stands. Most of the landscapes of the study region were dominated by spruce-deciduous stands, but in some landscapes with hilly relief, a predominance of spruce-pine stands was observed.

Effects of Strip Roads in a Pine Tree Stand (Pinus sylvestris L.) on the Diameter Growth and Pith Eccentricity of Trees Growing along Them

Although skid roads are more and more commonly used in Poland, they are still quite often criticised due to a certain loss of wood volume and the impact on edge trees. In this context, the results of the research described in this article can be used as a substantive contribution to discussions about strip roads. Research was carried out in a 42-year-old pine tree stand (Pinus sylvestris L.) in the Notecka Forest, where thinning had been performed and 2.5 and 3.5 m wide strip roads had been cut 10 years before. The analysis comprised two five-year periods recording diameter growth and pith eccentricity in trees growing at the distance zones of 0–1 m (adjacent trees), 2–4 m and 8–10 m (the control) away from the strip roads. The differences in growth and eccentricity between the different distance zones as well as the frequency of pith eccentricity in the N-W, S-W, N-E and S-E directions were assessed, related to the distance from the strip road and the measurement height. The measurements of the analysed traits were conducted on wood discs cut from the centres of two-metre-long sections on sample trees (12 trees in each distance zone). The trees growing directly beside the strip roads were statistically significantly thicker than those growing 8–10 m away, and in the case of the trees beside the narrower strip roads, in the second 5-year period, they were also thicker than the trees from the 2–4 m distance zone. The effect of the wider strip roads in the first growth period was also significant for the trees growing 3 m away from the strip road (their growth in this period was significantly greater than that of trees in the control zone). The research into tree-pith eccentricity showed no differences due to relative distance from the strip road. Furthermore, no statistically significant relationship between the distance of trees from the strip road, measurement height and frequency of tree-pith eccentricity to the N-W and S-W were found.

Long-Term Nitrogen and Phosphorus Dynamics in Waters Discharging from Forestry-Drained and Undrained Boreal Peatlands

Contradictory results for the long-term evolution of nitrogen and phosphorus concentrations in waters discharging from drained peatland forests need reconciliation. We gathered long-term (10–29 years) water quality data from 29 forested catchments, 18 forestry-drained and 11 undrained peatlands. Trend analysis of the nitrogen and phosphorus concentration data indicated variable trends from clearly decreasing to considerably increasing temporal trends. While the variations in phosphorus concentration trends over time did not correlate with any of our explanatory factors, trends in nitrogen concentrations correlated positively with tree stand volume in the catchments and temperature sum. A positive correlation of increasing nitrogen concentrations with temperature sum raises concerns of the future evolution of nitrogen dynamics under a warming climate. Furthermore, the correlation with tree stand volume is troublesome due to the generally accepted policy to tackle the climate crisis by enhancing tree growth. However, future research is still needed to assess which are the actual processes related to stand volume and temperature sum that contribute to increasing TN concentrations.

BIOSOCIAL DIVERSITY OF SCOTS PINE (PINUS SYLVESTRIS L.) IN A TREE STAND IN RELATION TO CHOSEN HYDRAULIC CONDUCTIVITY INDICATORS OF THE STEM

The research focused in determining the lignification indicator of fresh needled springs and the mass of fresh needles in reference to the lignin content in tracheid walls of peripheral area of the stem (MFT/LC and MFN/LC) of Scots pine differentiated as far as its biosocial position within the community expressed by Kraft’s classification. The material for the analysis came from mature pine stands growing on North European Plain, on the territory of Poland. Chemical and structural analyses of wood encompassed the area of mature sapwood, i.e. thickness of the last 10 annual rings located at 1.3 m (DBH). It seems that the noticed differences values of both indicators (MFT/LC and MFN/LC) in pines belonging to the first three Kraft’s biological classes are connected with physiological, physical and structural conditionings of water transport with minerals in xylem and are closely connected with competition for sunlight, water, nutrients and living space.

Tree stand mortality in nationally important park-monument of landscape art Feofaniya

Tree stand mortality in urban ecosystems indicates the influence level of biotic and abiotic factors primarily on their life state. The significance of these processes lies in the knowledge of the forest stands patterns development and their use for forecasting and assessing ecosystem services. The territories of the nature reserve fund have been taken as research sites, as significant indicators of anthropogenically altered territories. The structure of biomass and forest stands species composition was found to be associated with the growth and development of living trees and the formation of dead trees. Biotic and abiotic factors, intraspecific competition and peculiarities of local formation condition and stands growth are determined to affect the life state of the main forest-forming species directly and indirectly. It was revealed that in the medieval oak plantation, the loss of trees during the research period (2016-2020) prevailed over the increase in the stand ground phytomass. It was found that the carbon deposited amount in the forest stands aboveground phytomass reflects the unusual dynamics for the overwhelming number of territory indicators. The litter formation caused the changes in the deposited carbon structure of the research stands phytomass by tree species. It also led to an increase in the deadwood carbon pool and the onset of carbon emissions from the detritus decomposition.

Permafrost Biases Climate Signals in δ18Otree-ring Series from a Sub-alpine Tree Stand in Val Bever/Switzerland

During recent decades, stable oxygen isotopes derived from tree-ring cellulose (δ18OTRC) have been frequently utilised as the baseline for palaeoclimatic reconstructions. In this context, numerous studies take advantage of the high sensitivity of trees close to their ecological distribution limit (high elevation or high latitudes). However, this increases the chance that indirect climatic forces such as cold ground induced by permafrost can distort the climate-proxy relationship. In this study, a tree stand of sub-alpine larch trees (Larix decidua Mill.) located in an inner alpine dry valley (Val Bever), Switzerland, was analysed for its δ18OTRC variations during the last 180 years. A total of eight L. decidua trees were analysed on an individual base, half of which are located on verified sporadic permafrost lenses approximately 500 m below the expected lower limit of discontinuous permafrost. The derived isotope time series are strongly dependent on variations in summer temperature, precipitation and large-scale circulation patterns (geopotential height fields). The results demonstrate that trees growing outside of the permafrost distribution provide a significantly stronger and more consistent climate-proxy relationship over time than permafrost-affected tree stands. The climate sensitivity of permafrost-affected trees is analogical to the permafrost-free tree stands (positive and negative correlations with temperature and precipitation, respectively) but attenuated partly leading to a complete loss of significance. In particular, decadal summer temperature variations are well reflected in δ18OTRC from permafrost-free sites (r = 0.62, p < 0.01), while permafrost-affected sites demonstrate a full lack of this dependency (r = 0.30, p > 0.05). Since both tree stands are located just a few meters away from one another and are subject to the same climatic influences, discrepancies in the isotope time series can only be attributed to variations in the trees’ source water that constraints the climatic fingerprints on δ18OTRC. If the two individual time series are merged to one local mean chronology, the climatic sensitivity reflects an intermediate between the permafrost-free and –affected δ18OTRC time series. It can be deduced, that a significant loss of information on past climate variations arises by simply averaging both tree stands without prior knowledge of differing subsurface conditions.

Tree diversity and natural regeneration in Tropical Dry Deciduous Forest of Panna Tiger Reserve, India

The disturbance is a major factor driving the decline of tropical forests and their associated fauna. Henceforth, basic information on species diversity would be useful for assessing the success of management in the fragmented and human-disturbed landscape. We accounted for tree species diversity and their regeneration pattern from the tropical dry deciduous forest of Panna Tiger Reserve (PTR), India. Considering this, random vegetation sampling along with transects was carried out in different ranges of PTR. It is spread over in an area of 2998.98 km2 that situated in the northern part of Madhya Pradesh and distributed in Panna and Chhatarpur district. The tropical dry deciduous forest inventory in the 10.6132-ha area yielded a total of 46 woody species of > 10 cm GBH, belonged to 23 Families and 40 genera. The regeneration represented 27 species of < 30 cm height (seedling) under 16 families and 24 genera while sapling, which ranges from > 30cm to 1.3m, showed 24 species of 13 families and 32 genera. The Shannon diversity of Trees, seedlings, and saplings was 2.684, 2.525, and 2.401 respectively. A total stand density and basal area of 2391 stems of trees were estimated as 225.285 stand ha− 1 and 90.016 m2ha− 1 respectively. Tectona grandis scored the highest IVI value of 59.44 (19.81% of total IVI for all species) among the dominated tree species, followed by Acacia catechu (24.94), Abrus precatorius (23.25), Zizyphus xylopyra (22.94), Anogeissus latifolia (22.16) and Lagerstroemia parviflora (22.18). Nearly 23.913% of the total number of species was recorded as rare species. The highest seedling density was obtained for Diospyros melanoxylon followed by Zizyphus xylopyra, Aegle marmelos, Wrightia tintoria, and Tectona grandis, which declined in the subsequent sapling stage and showed a reverse pattern. Hence, the highest sapling density was recorded for Tectona grandis then Aegle marmelos, Wrightia tintoria, Diospyros melanoxylon, and Zizyphus xylopyra. A total of 36.956% of tree species were found to fail to establish in the community because species were represented by only adult or tree stage that listed as Not-regenerating. In terms of the most diverse family among the plant categories; viz. Tree, Seedling, Sapling, Fabaceae had the highest species richness. The highest tree stand density (127.576 stand ha− 1) was recorded in the girth class of 31-60cm (48.687% of the total tree stand density) followed by 10-30cm and 61-90cm. Likewise, a total basal area of 20.824 m2ha− 1 was occupied by 31-60cm that contributed 23.051% of the total basal area, so our data on the population structure of forest shows a similar trend wherein the distribution curve exponentially decreases with increasing girth classes that indicates not only a mid-successional forest but also a human-disturbed.