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.

Variation in Tree Layer Composition Across Mid and Higher Elevation Forest Sites in Kumaun Himalayan Region, Uttarakhand

The Himalayan forests are rich in biodiversity and distributed over a large extent from lower to higher elevations. The dependence of the locals for their daily requirements of fuel, fodder and medicinal plants is high on these forests. The study was conducted at altitude varied between 1725 and 3250 masl (above sea level) in Kumaun region. The study deals with the comparison of tree layer vegetation in higher elevation sites (HES) and mid elevation sites (MES) with reference to Diversity, Richness, Basal area (BA), Dominance and Important Value Index. The MES were dominated by mixed Quercus leucotrichophora and Pinus roxburghii forests where as HES sites were dominated by Quercus semecarpifolia and Aesculus indica forests and Rhododendron campanulatum in the understory. Across all the sites the tree species richness ranged between 9 and 15. Tree density was maximum (1400 trees/ha) at MES. Tree diversity and total basal area were maximum at HES. The study will be useful in developing baseline data for carrying out future studies. The data generated will be helpful for the conservation of biodiversity of the region.

Variation in floristic and trait composition along environmental gradients in the herb layer of temperate forests in the transition zone between Central and SE Europe

Species- and trait-environment linkages in forest plant communities continue to be a frequent topic in ecological research. We studied the dependence of floristic and functional trait composition on environmental factors, namely local soil properties, overstory characteristics, climatic parameters and other abiotic and biotic variables. The study area comprised 50 monitoring plots across Slovenia, belonging to the EU ICP Forests monitoring network. Vegetation was surveyed in accordance with harmonized protocols, and environmental variables were either measured or estimated during vegetation sampling. Significant predictors of species composition were identified by canonical correspondence analysis. Correlations between plant traits, i.e. plant growth habit, life form, flowering features and CSR signature, were examined with fourth-corner analysis and linear regressions. Our results show that variation in floristic composition was mainly explained by climatic parameters (mean annual temperature, mean annual precipitation), soil properties (pH) and tree layer-dependent light conditions. Trait composition was most closely related with tree layer characteristics, such as shade-casting ability (SCA, a proxy for light availability in the understory layer), tree species richness and tree species composition. Amongst soil properties, total nitrogen content and soil texture (proportion of clay) were most frequently correlated with different species traits or trait states. The CSR signature of herb communities was associated with tree layer SCA, soil pH and mean annual temperature. The floristic composition of the studied herb-layer vegetation depended on temperature and precipitation, which are likely to be influenced by ongoing climate change (warming and drying). Trait composition exhibited significant links to tree layer characteristics and soil conditions, which are in turn directly modified by forest management interventions.

Forest recultivation of overburden dumps of the Kingisepp phosphorite field

The article is devoted to the study of the stages of forest recultivation of overburden dumps of the Kingisepp phosphorite field’s breed located in the North-West of the Russian Federation. 5 test areas with a total area of 63.7 hectares were laid to study the different stages of recultivation. In the course of the study, the author’s team identified four conditional stages of the formation of the spruce community of the forest recultivation of overburden dumps breed. The first stage, which has the conditional name ‘10 years’ is newly planted spruce trees on the recultivation territory. The second stage of the formation of the spruce community (‘20 years’) is that the European spruce passes into the stand. The third stage of community formation (‘30 years’) consists in the growth of all plantings to the level of a stand and in the creation of a birch-spruce or spruce-birch forest, since at the age of more than 30 years European spruce in recultivation by itself territories can occupy up to 50% of the stand. At the fourth stage, spruces displace birch trees from the community, remaining almost the only representative of the tree layer.

Comparative analysis of Scots pine homogeneous stands bioenergetic productivity in European North

The bioenergetic productivity of artificial pine stands is considered. It was found that in 30-year-old artificial pine coenoses, the lowest amount of energy associated with the tree layer is observed in the lichen type of growing conditions (443,1 GJ/ha), the highest — in the blueberry (1915,1 GJ/ha). Bioenergetic productivity occupies an intermediate position (1210,7 GJ/ha) in the cranberry-type forest culture phytocenoses. It is shown that the accumulated energy reaches the highest relative value in such a component of aboveground phytomass as trunk wood. For this fraction, the variation is observed from 50.2% in the lichen type of growing conditions to 65.8% in the blueberry type, based on the total stock of phytomass of forest crops. It is established that the secondary position relative to this indicator is occupied by woody greens. The share of the energy productivity of needles in the total aboveground phytomass decreases with the improvement of forest growing conditions. An approximately equal ratio of energy deposition in the studied types of artificial pine forests by the fractions of bark and live branches (7,2...11,7%) was determined, and the smallest share of accumulated energy falls on the fraction of dry branches (5,3...7,0 %).

Phytosociological analysis of noble hardwood forests (Ostryo-Tilienion platyphylli) in the Karst and its neighbouring regions (SW Slovenia)

In SW Slovenia, at Gora under Železna Vrata and Petnik gorge near Branik – both on the northern edge of the Karst, in the collapse doline Orleška Draga at Sežana and under Brkinski Rob at the contact of the Karst and Brkini Hills, we conducted a phytosociological analysis of the stands whose tree layer is dominated by Tilia platyphyllos, T. cordata, Acer pseudoplatanus, Ulmus glabra, in places also Carpinus betulus and Ostrya carpinifolia, and classified them into three associations, Corydalido ochroleucae-Aceretum pseudoplatani, Paeonio officinalis-Tilietum platyphylli and Fraxino orni-Aceretum pseudoplatani. The latter was described as a new. Also new is a secondary large-leaved lime association Lamio orvalae-Tilietum platyphylli on the sites of montane beech forests (Lamio orvalae-Fagetum) in the Čepovan valley, at the contact of the Dinaric and sub-Mediterranean phytogeographical regions of Slovenia.

Accounting for carbon exchanges in a semiarid oak savanna (dehesa).

<p>Semiarid oak savannas (grasslands with scattered trees), partially covered, subject to regular droughts, grazing, and high levels of solar radiation, are nonetheless, typically carbon sinks regarding CO2. However, dehesas are a productive system, a trait shared with other savannas, and they are shaped by their uses for economic production. One of its multiple uses, livestock extensive farming, key to its economic profitability and to the preservation of the agrosilvopastoral system structure, modifies the Greenhouse gas (GHG) balance by adding a significant amount of CH4 and N2O into the cycle. Recent reports and publications have evaluated and compared different types of livestock management within the context of climate change. GHG emissions, extensive use of the soil resource, or the introduction of nitrogen into the system, are some of the generated effects that cause a negative evaluation of extensive farming. Nevertheless, the importance of this sector, given its extension and impact on production and rural development, demands a more rigorous evaluation. It is necessary to precisely account for the fluxes in their totality (including the CO2 sink effect) and the relationships between them. Currently, there are few studies that determine the GHG balance of dehesas, and they are mainly centred on CO2 fluxes without integrating the influence of livestock, or in meadows without a tree layer (which changes the CO2 balance). The net global warming potential of dehesas is unknown, given that very few direct and long-term flux measurements have been taken on them. In this work, CO2 and H2O fluxes from an eddy covariance tower located in an Andalusian dehesa were processed (standard corrections), filtered and homogenized, including filling gaps using artificial neural networks. We calculated the annual CO2 budget since 2015, to assess the sink/source nature of the area. In a modeling exercise to be able to close the carbon cycle, we estimated CH4 and N2O depending on the number of livestock present in the area by season/year, evaluating the tipping point.</p>