Volume 75 (2021): Issue 1 (December 2021)

Gross Primary Productivity (GPP) is the core component of the terrestrial and global carbon cycle and Earth’s climate research. In this study, GPP estimation was performed with the Boreal Ecosystem Productivity Simulator (BEPS) model to check its performance for hemi-boreal forests on the example of the Soontaga area in Estonia. The model was run by using a combination of remote sensing (leaf area index (LAI), clumping index) and meteorological data inputs (air temperature, global radiation, air humidity, precipitation and wind speed). The results were validated against GPP derived from the available flux tower measurements. The spatial representativeness of the site was evaluated using multiple spatial thresholds (500 m^–2 km), as well. We found that the BEPS model can track the GPP changes with the season and inter-annual variation very well in a coniferous hemi-boreal forest, given that good quality input data are provided.

The study area is in the Järvselja Training and Experimental Forest Centre, Estonia. The conservation of Järvselja old-growth forest started in 1924 when the area was excluded from all management activities and left to natural development. The aim of this study is to analyse the methods for calculating single tree height, tree stem lateral surface area, tree volume and carbon content for standing live trees, standing dead trees and for downed deadwood in old-growth forests. The study used the data of 6205 live trees, 1119 snags, 270 standing dead trees and 2983 deadwood trunks from the measured area. The most abundant tree species in Järvselja old-growth forest were Norway spruce and linden. During the last hundred years, the number of dominating tree species has increased slightly. The standing volume of birch, common aspen and Scots pine have been declining while for linden and black alder it has been increasing. In the comparison of tree height curves, the best results were obtained with the Näslund function, however, the Chapman-Richards function with fitting showed slightly better results for two tree species.

In this paper we carried out a comparative analysis of three alliances, namely Quercion petraea, Betonico-Quercion and Lathyro-Quercion, which span Central and Eastern European thermophilous oak forests. The main goal was to find out floristic and ecological differences as well as to assess specificities in the phytosociological and layer structure across the syntaxa in different regions of Europe. Cluster analysis was performed based on the Bray-Curtis distance matrix and the flexible beta algorithm. A phytoindication method was applied to determine ecological relationships. Variability in the phytosociological structure was studied by shares of species of different classes of vegetation. The layer structure features were investigated by comparing species with the highest constancy value within each layer. Analysis of the distribution boundaries of differentiating species allowed the geographical boundaries of the three identified syntaxa clusters to be delineated. In the phytosociological structure, the greatest differences were found in the proportion of species of Quercetea pubescentis and Brachypodio-Betuletea classes. The Central and Eastern European syntaxa groups were shown to be significantly different in the constancy-ranked series of major layer-forming species.

The increasing demand for raw materials favours habitat conversion into tree plantations in different biomes over the world. In Argentina, fast-growing plantations occur in physiognomically contrasting biomes, such as the subtropical forest and grassland. Our objectives were to analyze variations in basic habitat metrics and their similarity to the natural habitat along pine plantation cycles, and to compare those patterns between plantations developing in a subtropical forest and a grassland biome. In each biome we selected pine stands of eight ages to represent the environmental gradient of the forest cycle, and natural areas. At each site we estimated the temperature, thermal variability, relative humidity, and percentage coverage of herbaceous plants, shrubs and canopy. We explored environmental similarity between plantations and the natural habitat. In general, patterns of the environmental variables along plantation chronosequences were similar between plantations developing in different biomes. As expected, opposite patterns of similarity in most environmental variables between plantations and the natural habitat were observed along chronosequences developing in contrasting biomes. The time period of high environmental similarity between plantations and the natural environment was longer in the subtropical forest than in the grassland. Our results have implications for land use planning and biodiversity conservation.

We investigated the distribution of extractive, phenolic, and polysaccharides content of young S. mahagoni trees aged 1 to 5 years. The wood powder materials in two vertical positions (bottom and top) were successively extracted using n-hexane, methanol, and hot water solutions. The results showed that there was a significant interaction between the tree age and axial position in all parameters. The methanol and total extractive content decreased significantly from 1 to 3-year-old at the top part. In contrast, the amount of hot water and total extractive increased significantly from 3 to 4-year-old trees at the bottom part. Furthermore, a significant increase was also found at the bottom heartwood for hexane, methanol, and the total extractive from 4 to 5-year-old trees. The reverse trend was observed in the polar fractions (methanol and hot water) at the top of the trees. Generally, the extractive pattern tends to decrease from bottom to top with the highest proportion of methanol extract (70% based on the total extractive weight), and it increased from sapwood to heartwood. The total phenolic content (TPC) and total soluble polysaccharides (TSP) generally increase with tree age (except for TSP from 2 to 3-year-old trees at the top part). The high content of TPC in the heartwood and TSP in the sapwood indicated the process of heartwood formation. In addition, a drastic decrease in the methanol extract and TSP at the age of 3 years at the top indicated that the TSP was transferred from top to bottom for the heartwood formation at the bottom part of 4-year-old trees.

Tree species inventories, particularly of poorly known dry forests, are necessary to protect and restore them in degraded landscapes. The present research has been conducted to compare taxonomic diversity and community composition in four dry forests (DF) categories with different standing volume levels: very low (DFV), low (DFP), medium (DFM) and high (DFR). This quantitative assessment of taxonomic diversity, forest structure and species composition were obtained from 103 sample plots (0.1 ha each). The regeneration potential of trees was assessed in 515 subplots (4 m × 4 m) located within the 103 plots. A total of 1,072 trees representing 87 species belonging to 37 families were recorded in 10.3 ha of total sampled area. The ranges of diversity indices observed in the four forest types were: Margalef's (5.44–8.43), Shannon-Wiener (1.80–2.29), Simpson diversity (0.76–0.87) and evenness (0.32–0.35). The regeneration potential of rare and threatened species Dalbergia oliveri, Hopea recopei, Dalbergia bariensis, Sindora siamensis, Parashorea stellata was observed to be poor. Conversely, Cratoxylon formosum, Shorea obtusa, Dipterocarpus tuberculatus, Dipterocarpus obtusifolius, Terminalia alata, Shorea siamensis and Xylia xylocarpa were the most dominant species at the seedling and sapling stage, showing a strong potential for regeneration. Overall, this study provides useful information on tree species diversity and composition for tropical dry forests which can be used as baseline data to develop incoming plans for forest management and conservation in Vietnam's Central Highlands Region.

This paper aimed to study the distribution of the main tree species in the Republic of Bashkortostan (RB) in a transforming climate and compare the results for the last decades. The analysis was based on the forest fund data, forest management documents, route surveys and field studies, and conducted by generally established forestry methods. The trial plots had identical soil conditions. The paper considers the impact of climate on the forest resources of the RB located at the junction of the Urals with the West Siberian Lowland, the Cis-Ural plain and steppe belt with diverse vegetation. The floristic composition of the republic is varied and includes about 1700 species of higher plants. Comprehensive research was followed by field results comparison. In 1998–2018, the area of soft-leaved species, primarily Betula pendula Roth and Tilia cordata Mill. increased by 70.8 (39%) and 74.2 thousand hectares (32%), respectively; the share of coniferous Picea and Abies declined by 57.9 thousand hectares – 15%, short-trunk Quercus robur L. lowered by 34% and the high-trunk one decreased by 6% and Acer by 8%. The conducted study suggests a significant increase in destructive insects. Spruce forests will suffer, because there is a reduction in the area by 20% over 20 years. Thus, there has been a gradual displacement of forest species. Forestry challenges and the sustainable ecological balance both in the republic and the planet as a whole require further joint efforts of scientific and environmental organisations and authorities for forecasting transformational processes and developing measures to address them.

Knowing and analyzing the effect of the successful implementation of forest management policies mediated by community empowerment by moderating a network of actors and stakeholder collaborations. This study uses a quantitative approach to examine specific populations and samples. The research instrument is a questionnaire. The sample in this study were 100 people around the KPHP Model Yogjakarta. The analytical tool used Structural Equation Modeling (SEM) WarpPLS and IPA approaches. Communication, resources, environmental conditions, and relationships between organizations have a direct and significant effect on community empowerment, and the empowerment variable has a direct and significant effect on the successful implementation of forest management policies. The variables that do not directly affect the disposition and organizational structure variables do not significantly influence community empowerment. The influence of actor-networks and stakeholder collaborations as moderation which strengthens implementation of community empowerment and successful implementation is a novelty in research.

Estimations of forests’ carbon sequestration capacity relies on proper assessment of the eddy covariance measurement mast’s footprint. Harsh winter temperatures in Estonia lead to ice formation on 3D sonic anemometer sensor heads and thus induce measurement gaps in the data. To maximise data availability, we use a smart heating algorithm to minimise ice formation on the anemometer sensor heads. Here, we studied the temperature distribution of ice formation on the measurement instruments. Three major temperature ranges were found, between 0°C and −3°C, which is the most abundant temperature range for ice formation, and two temperature regions with peaks around −10°C and −20°C. Our algorithm to prevent ice formation led to very short median heating intervals of about 25 to 30 seconds.

This article demonstrates that it is possible to optimize the drying process for pine wood in two independent ways. Those ways involve either the use of the critical diffusion coefficient (DC) which is determined by the experiment shown below, and/or the drying air moistening impulse in the second drying phase. When processing data which has been gained from the pine wood drying experiment, both coincidences and differences were found when compared to the results from a simulation of the drying process which was carried out using the same drying schedule. There is a relatively good level of agreement between the drying experiment and the simulation results of TORKSIM v5.11 simulation program in the case of the simulated and experimentally determined drying curves. The magnitude of numerical values for the DC agrees with this finding, as do the wood's moisture profile in the final phase of the drying experiment at 142 hours, the simulated and measured wood surface temperatures from the beginning of drying to a point at 60 hours into the process, and the simulated wood stresses when compared with the maximum values for the electrical surface-core ratio (ESCR) graph, as determined by the experiment. It was found that the DC's numerical value decreases sharply by about 1.5 times after transitioning from the first drying phase to the second drying phase.

In the greenhouse, mixed inoculation of Tetraclinis articulata (Vahl) Mast.) with Rhizoctonia solani Kühn and Fusarium solani (Mart.) Sacc. caused remarkable damping-off and root rot compared to simple inoculation with one of the two pathogens. Root and stem infections caused significant reduction in plant growth. Root system total length was reduced by 36 to 43% and shoot height losses by 28 to 39%. Plants inoculated by one pathogen were shorter than control plants or inoculated plants by both pathogens. Disease severity ratings for plants infested with the pathogens mixture also were greater than with either pathogen alone up to 62 days post-inoculation. R. solani and F. solani interact synergistically, causing severe damping-off and root rot in T. articulata seedlings.

The study material of Scots pine sample trees originated from five different forest site types (Cladonia, Calluna, Myrtillus, natural raised bog and drained raised bog) in Estonia. Altogether, 60 trees were sampled from 10 stands. From these, test disks and sample blocks (1.2 m in length) were cut at 1.3 m height, 1/2 of tree height and 3/4 of tree height. We analysed the effect of forest site type on the growth of tree ring width, proportion of late- and heartwood, oven-dry density, bending and compression strength and wood hardness. Wood properties in stands of the same age showed great variability. Significant differences were found in the wood properties between site types. Wood density and strength characteristics were higher in samples from heath site types than from the sites more optimal for pine (e.g., Myrtillus). The quality of the wood from peatland stands was lower than from trees grown on mineral soil. The decreasing trend in strength properties towards the top of trees was steeper in the wood formed under poor nutrient conditions. Latewood proportion increased with tree age. However, in the case of equal latewood percentages, heartwood density was higher than sapwood density.

Our work is part of the ex situ conservation of the Atlas cedar (Cedrus atlantica (Manetti ex Endl.) Carrière), a threatened and endemic Pinaceae of the Maghreb. Our objectives are to evaluate the viability of seeds from three Algerian cedar groves ecotypes (Thienet El Had, Chelia, Chrea) by the 2,3,5 triphenyltetrazolium chloride (TZ) test and to elucidate the effect of continuous temperatures (15°C, 20°C, 25°C) on their germinative capacity. Moreover, the effects of some physicochemical pretreatments in breaking dormancy and improving germinability were estimated on the seeds of the cedar grove of Thienet El Had. In addition, in the same ecotype, the water stress, as simulated by using the PEG₆₀₀₀ (0 to −2.20 bar), was induced upon seed germination. Results of the TZ test showed variability in seeds’ viability among the three ecotypes with rates of 60, 85 and 90% in those of Chelia, Chrea and Thienet El Had, respectively. However, germination tests revealed the existence of partial dormancy in all tested seeds. Dramatic differences in the degree of dormancy were noted among the three provenances investigated. Untreated seeds of the three ecotypes exhibited maximum germination at 20°C: Thienet El Had (52%), Chelia (32%) and Chrea (7%). The final germination percentage was as high as 76% in seeds soaked in hot water (80°C) for 5 min followed by 56% in seeds treated with GA₃ (150 ppm). The increase in water stress regularly decreases germination with a tolerance threshold corresponding to −2.2 bar.

The article provides an overview of the results of the maturity age calculations for economically important tree species’ stands in Estonian commercial forests. The maturity by price is determined by a stand’s stumpage value per year of rotation. The maturity by net income (forest rent) is determined by the average annual net income of forest management, which is calculated based on the timber sales revenue, forest management costs and rotation period. The annual land tax and administrative costs have been included in the calculations, as well. The calculated maturity ages are compared with the required rotation ages stated in the Rules of Forest Management. According to the calculations, the maturity age by net income for pine stands in Ia and I site classes is 10…20 years lower than the current rotation age for regeneration felling. The maturity ages for spruce stands coincide with the current rotation ages. The calculated maturity ages by net income for aspen are about ten years higher than the current rotation ages. A comparison of the calculated maturity ages with the current rotation ages shows that these are rather similar.