A Static Pulling Test Is a Suitable Method for Comparison of the Loading Resistance of Silver Birch (Betula pendula Roth.) between Urban and Peri-Urban Forests

In urbanized areas, wind disturbances can be intensified by anthropogenic stresses under which trees may become hazardous, creating serious threats and damages to nearby targets. Therefore, species with notably lower both wood mechanical properties and compartmentalization, such as pioneers, are considered to have higher wind damage risk if subjected to unfavorable growing conditions. Eurasian aspen (Populus tremula L.) and silver birch (Betula pendula Roth.), are frequently found in both urban and peri-urban forests in Northeastern and Central parts of Europe, which strengthen the necessity for the evaluation of mechanical stability of such species. Therefore, static pulling tests were performed to compare the mechanical stability of the studied species in both urban and peri-urban forests. The loading resistance of the studied species differed, with birch being more stable than aspen, indicating aspen to be more prone to wind damage. Additionally, the mechanical stability of birch did not differ between trees growing in urban and peri-urban forests, suggesting static pulling tests are a suitable method for comparing trees from completely different growing conditions.

Effect of Drought and Heavy Metal Contamination on Growth and Photosynthesis of Silver Birch Trees Growing on Post-Industrial Heaps

Silver birch trees (Betula pendula Roth) are a pioneering species in post-industrial habitats, and have been associated with an expansive breeding strategy and low habitat requirements. We conducted ecophysiological and dendroclimatological studies to check whether there are any features of which the modification enables birch trees to colonise extreme habitats successfully. We characterised the efficiency of the photosynthetic apparatus, the gas exchange, the content of pigments in leaves, and the growth (leaf thickness and tree-ring width) of birch trees on a post-coal mine heap, a post-smelter heap, and a reference site. Birch growth was limited mainly by temperature and water availability during summer, and the leaves of the birch growing on post-industrial heaps were significantly thicker than the reference leaves. Moreover, birch trees growing on heaps were characterised by a significantly higher content of flavonols and anthocyanins in leaves and higher non-photochemical quenching. In addition, birches growing on the post-coal mine heap accumulated a concentration of Mn in their leaves, which is highly toxic for most plant species. Increasing the thickness of leaves, and the content of flavonols and anthocyanins, as well as efficient non-photochemical quenching seem to be important features that improve the colonization of extreme habitats by birches.

Synthesis and properties of nanosized ZnO/wood composite

The aim of the study was to synthesise a ZnO/silver birch wood (Bétula péndula) nanocomposite and evaluate its physical and mechanical properties in comparison with an unmodified natural polymer.Using the sol-gel method, we synthesised almost spherical impurity-free zinc oxide nanoparticles with a predominant particle size of about 20 nm. Amorphous hydrated Zn(OH)2 was impregnated into the wood material at the gel formation stage. It resulted in the reaction of zinc hydroxide decomposition with the formation of ZnO nanoparticles in the wood as a nanoreactor.The hydrophobic properties of the surface of ZnO/silver birch wood nanocomposite improved significantly (the contact angle of wetting doubled). Its moisture and water resistance decreased (2-5 times and 30%, respectively). The nanocomposite also showed less swelling in the radial (8-10 times) and tangential (2.6-10 times) directions in comparison with natural wood.

Applied aerial spectroscopy: A case study on remote sensing of an ancient and semi-natural woodland

An area of ancient and semi-natural woodland (ASNW) has been investigated by applied aerial spectroscopy using an unmanned aerial vehicle (UAV) with multispectral image (MSI) camera. A novel normalised difference spectral index (NDSI) algorithm was developed using principal component analysis (PCA). This novel NDSI was then combined with a simple segmentation method of thresholding and applied for the identification of native tree species as well as the overall health of the woodland. Using this new approach allowed the identification of trees at canopy level, across 7.4 hectares (73,934 m2) of ASNW, as oak (53%), silver birch (37%), empty space (9%) and dead trees (1%). This UAV derived data was corroborated, for its accuracy, by a statistically valid ground-level field study that identified oak (47%), silver birch (46%) and dead trees (7.4%). This simple innovative approach, using a low-cost multirotor UAV with MSI camera, is both rapid to deploy, was flown around 100 m above ground level, provides useable high resolution (5.3 cm / pixel) data within 22 mins that can be interrogated using readily available PC-based software to identify tree species. In addition, it provides an overall oversight of woodland health and has the potential to inform a future woodland regeneration strategy.

FOREST RECLAMATION COMPLEXES OF THE ROSSOSHANSKY DISTRICT OF THE VORONEZH REGION

Forest reclamation complexes in the Rossoshan district of the Voronezh region are mainly represented with the participation of white acacia, silver birch, green ash, common elm and Tatar maple. The area occupied by them in the agricultural landscape is 2009 hectares. In cultures of hanging birch at the age of 19 years with a change in width from 6.0 m to 15.0 m, there is a decrease in the preservation of species by 8.8% and a decrease in wind protection height by 16.5% with a plant density of 3334 pcs / ha and placement of 3 , 0 x 1.0 m. According to the growth of plantings, they are estimated as Ia class of bonitet. In mixed crops aged 34 years, consisting of fast-growing and accompanying species with a planting width of 16.0 m, the highest height is for drooping birch (20.1 m), the lowest for green ash (14.3 m). The safety of such breeds is 46.8% and 60.6%, respectively. Forest belts, represented by white acacia, drooping birch, Tatar maple at the age of 36 years, have a preservation of species of 38.3-55.2%. The drooping birch has the highest height (22.4 m). In artificial linear plantations, consisting of common elm, drooping birch, Tatar maple and green ash at the age of 38 years, the greatest preservation is observed in the Tatar maple (54.7%), the lowest in green ash (32.7%). The drooping birch has the greatest windproof height (20.6 m) and is estimated in growth according to the Ia class of bonitet. Each breed has certain ecological and biological properties.

Scots Pine (Pinus sylvestrisL.) Undergrowth on the Dumps of the Chrysotile Asbestos Deposit

The studies were carried out on the dumps of overburden rocks and tailings of poor ores of the chrysotile asbestos deposit. According to the scheme of forest site zoning, the studying area belongs to the pre-forest steppe district of pine and birch forests of the Zabaikal’ye plain province of the West Siberian plain forest site area. The survey sites were laid out on the terraces of the dump along the running lines. Undergrowth was counted at each survey site. It was classified by viability, size (small, medium, large), and life form (tree, bush, scrub). The provision with undergrowth of the indicated type of disturbed soils was defined and recommendations for measures aimed at accelerating the process of reforestation were given. Undergrowth on the dumps is represented by Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth.), aspen (Populus tremula L.), and goat willow (Salix caprea L.). Scots pine and silver birch are the dominant species in the undergrowth composition. Large share of Scots pine of scrub and bush form is the specific feature of the developing young growth. These specimens were found among small- and medium-sized undergrowth. It is the undergrowth of these heights that becomes an annual attrition without passing into the large-sized category. The latter is the main reason for faster conversion of the dumps into forest-covered area, for increasing the share of clay particles in the upper 50 cm thick dump layer, or for coating the dump surface by non-traditional fertilizers, in particular sewage sludge. It was noted that silvicultural trend in the dump reclamation on the chrysotile asbestos deposit is the most preferable. Scots pine should be preferred as the primary species for reclamation planning. For citation: Zaripov Yu.V., Zalesov S.V., Zalesova E.S., Popov A.S., Platonov E.P., Starodubtseva N.I. Scots Pine (Pinus sylvestris L.) Undergrowth on the Dumps of the Chrysotile Asbestos Deposit. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 22–33. DOI: 10.37482/0536-1036-2021-5-22-33