Altitudinal variation in plant community, population structure and carbon stock of Quercus semecarpifolia Sm. forest in Kumaun Himalaya

Aim: To study the impact of altitudinal variation on plant community composition, structure, dispersion and regeneration status of Quercus semecarpifolia forest in Kumaun Himalaya. Methodology: Along the altitudinal gradient, the forest stands between 2400 and 2610 m asl were selected at low, mid and high altitude. The phyto-sociological analysis was carried by laying ten quadrats of 10m × 10m at each site. Soil samples were collected with the help of soil corer from two depths. Various ecological indices and population structure were investigated for each forest stand and regeneration status of forest was predicted by the population size of seedlings, saplings and trees. Tree biomass was estimated using allomatric equations and carbon stock was determined by multiplying biomass of species to factor 0.475. Results: With increasing altitude the number of tree species decreased and the shrub species richness increased, while herb species showed a unimodel pattern. Q. semecarpifolia was the dominant tree species at all the three sites with the IVI values of 220.14, 255.22 and 286.23 at LA, MA and HA, respectively. A complete absence of Q. semecarpifolia seedlings indicated no regeneration in low and high altitude stands while low proportion of seedlings in mid altitude forest stand indicated poor regeneration. Soil was acidic (pH 5.66-5.86), with higher silt content and showed decreasing pattern in physico-chemical properties with increasing altitude. The biomass of tree layer ranged from 871.49 to 1050.17 t ha-1. The tree layer carbon stock was maximum in high altitude forest (498.84 t ha-1) which was largely contributed by bole, stump roots and branches. Interpretation: Variation in species richness, distribution pattern and regeneration potential is related to site characteristics governed by altitude and require various efforts to conserve and protect these forests to check ecosystem imbalance.

Practical approaches to determining the dynamics of the stability of stands of breeding objects

The article analyzes the indicators that can be used to assess the biotic and ecological stability of forest stands. For breeding facilities, this issue is of relevance when prescribing reforestation measures in forest genetic reserves, assessing the stability when selecting plus stands, assessing selected permanent forest-seed plots to determine the volumes of their formation and tending activities in them and, in the future, their transfer to plus stands, as well as, in general, for isolation of a reserve fund from the forest environment. The methods for assessing the stability of forest stands are based on determining the indicators of forest stand stability, calculated on the basis of tree mensuration in the study area (based on a trial plot) and the sanitary state of the trees. The basis for the determination is the complete tree enumeration and the scale of sanitary state used in production operations (SanitaryForestsReg.Ukraine). The assessment of stand stability is based on the method of calculating the loss of stability (BC)), which was proposed to determine the stability of secondary spruce forests in fertile beech forest types (BlystivV. I. 2006) and later adapted to assess the formation of the stability of hornbeam-beech stands (Blystiv V. I., 2012). The issue of assessing the tension of a stand, using the growing space of the forest is addressed in the methods section of the dissertation work by V.M.Malyuga, 2020. Using the values of the above indicators (KC, ВбС, ВеС), stands can be divided into 3 categories of stability: stable, conditionally stable and unstable. Appropriate forestry activities are proposed according to the categories. They require a special numeric-expressed substantiation, both in relation to the economic group of forest types, forest category, and for targeted activities or research areas - in this case, loss of stability of breeding facilities. Tension studies have shown that by using factors of environmental impact, the conditions are assessed as normal, non-tensioned and tensioned. To assess the indicator values of normal and weakened states, the basic scale of the assessment of biotic stability by stand indexes will be used. For the weakened state, three indexes are identified for the purpose of detailed planning of possible activities. In forest breeding, the selection and formation of forest stands for stability will require parameter-defined indicators, in this case, the forest stand stability coefficient is used. The protective properties of the forest environment, identified with the preservation of genetic diversity, determined by the amount and quality of natural regeneration and associated with ecological stability, can be effectively assessed by its loss according to the above method. The studies on the stand tension, using the factors of environmental impact, have shown that stands growing under tension are those that are somewhat overstocked ones. Pine stands grow optimally when they have a density range of 0.7-1.0. The rest of the stands grow without tension, but they do not make full use of growing space due to varying degrees of stand density. Such medium-stocked stands can be effectively used as selected and appropriately formed permanent forest-seed plots. Assessment of the stand state by impact factors makes it possible to record quantitative changes. The dynamics of areas in accordance with the changes of these indicators by periods characterizes the ecosystem changes (stages of development by successive process) and is important for the facilities of preservation of genetic diversity - especially forest genetic reserves.

Discrimination of forest species using medium spatial resolution images

This research aimed to evaluate the potential of orbital images from the Landsat-8/OLI and Sentinel-2 /MSI sensors in the distinction of species from a forest stand located in Campo Belo do Sul, State of Santa Catarina, Brazil. A total of 53 plots were allocated in the field, in which the central coordinate of the plot was collected using GPS receivers. In SIG environment, two images were used, one from each sensor, closely dated to the field campaign and with no clouds and other atmospheric factors. Then, the images were processed, and 17 vegetation indexes were calculated for each one. The indices were compared statistically by the t-Student test for independent samples. The indices that provided the best species differentiation were: CRI, GNDVI, NDI11, NDI12, NDVI, RDVI, SAVI, and SR. In addition, the species with greater prominence in the Landsat-8/OLI images was Eucalyptus spp. whereas Cunninghamia lanceolata (Lamb.) Hooker was easily distinguished in Sentinel-2 images. It was possible to differentiate the species from remote data derived from the Sentinel-2/MSI and Landsat-8/OLI sensors. However, further studies using other Remote Sensing data sources and other species are suggested.

The main drivers for the occurrence of six red-listed epiphytic bryophytes and lichens in the boreo-nemoral forest landscape, Latvia

Forest landscape plays a significant role in rare cryptogam distribution. However, data about the environmental demands of rare epiphytic bryophytes and lichens in boreo-nemoral forest landscapes are not complete. In this study, we focused on finding the main environmental predictors influencing the occurrence of three red-listed epiphytic bryophytes and three red-listed epiphytic lichens in the Latvian boreo-nemoral forest landscape. We obtained the records of species from the Natural Data Management System OZOLS database, which is a national information system on all rare taxa. We analyzed the occurrence of species in relation to forest stand age and area, forest type, heterogeneity and tree bark pH class. We found that selected red-listed bryophyte and lichen occurrence was mainly influenced by forest stand age and area. However, each of the red-listed epiphytic bryophyte and lichen has their own ecological demands in the boreo-nemoral landscape.