Variations of the Oxidative Ratio across Ecosystem Components and Seasons in a Managed Temperate Beech Forest (Leinefelde, Germany)

The oxidative ratio (OR) of organic material integrates the ratio of CO2 sequestered in biomass vs. O2 produced over longer timescales, but the temporal and spatial variability within a single ecosystem has received very limited attention. Between October 2017 and October 2019, we repeatedly sampled leaves, twigs, bark, outer stem wood, understorey vegetation and litter in a temperate beech forest close to Leinefelde (Germany) for OR measurements across a seasonal and spatial gradient. Plant component OR ranged from 1.004 ± 0.010 for fine roots to 1.089 ± 0.002 for leaves. Inter- and intra-annual differences for leaf and twig OR exist, but we found no correlation with sampling height within the canopy. Leaf OR had the highest temporal variability (minimum 1.069 ± 0.007, maximum 1.098 ± 0.002). This was expected, since leaf biomass of deciduous trees only represents the signal of the current growing season, while twig, stem and litter layer OR integrate multiple years. The sampling years 2018 and 2019 were unusually hot and dry, with low water availability in the summer, which could especially affect the August leaf OR. Total above-ground OR is dominated by the extremely stable stem OR and shows little variation (1.070 ± 0.02) throughout the two sampling years, even when facing extreme events.

Composition of Organic Carbon-Based Compounds in the Stem Wood of Quercus mongolica Seedlings Grown Under Elevated CO2 and/or O3 Concentrations

In this study, we examined the composition of organic constituents of stem woody tissue together with tree growth in Quercus mongolica var. grosseserrata Blume seedlings raised under controlled CO2 and/or O3 concentrations in a Free-Air Concentration Enrichment system. After exposure to ambient air (control), elevated CO2 concentration (550 μmol mol–1 CO2), elevated O3 concentration (double that of the control), and a combination of elevated CO2 and O3 concentrations during a growing season, we measured the diameter and length of stem, and biomass of sampled seedlings and quantified the lignin, extractive, and holocellulose contents of the woody tissue of current-year stems. We confirmed that the growth of seedlings was enhanced under an elevated CO2 concentration condition. In line with this, the extractive content was lower in woody tissue formed under an elevated CO2 concentration than that formed under ambient air, whereas holocellulose content showed an inverse pattern. Elevated O3 concentration itself did not change the organic constituents of the woody tissue, but it reduced the influence of an elevated CO2 concentration. We thus assume that Q. mongolica formed woody tissue with a low extractive content under the high CO2 concentration condition, although this response was possibly mitigated by an elevated O3 concentration. Extractives contains antimicrobial components such as tannins, flavonoids, quinones, and terpenoids. The decrease in extractives within the widely distributed Q. mongolica in East Asia may have a non-negligible impact on C cycling in the future earth with high atmospheric CO2 concentration.

Liana functional assembly along the hydrological gradient in Central Amazonia

Soil hydrology, nutrient availability and forest disturbance determine the variation of tropical tree species composition locally. However, most habitat filtering is explained by tree species' hydraulic traits along the hydrological gradient. We asked whether these patterns apply to lianas. At the community level, we investigated: (i) whether the hydrological gradient, soil fertility and forest disturbance explain liana species composition; and (ii) whether differences in leaf and stem wood functional traits were linked to species composition along ecological gradients. We sampled liana species composition in 18 1-ha plots across a 64 km² landscape in Central Amazonia and measured ten leaves and stem wood traits across 115 liana species in 2,000 individuals. We correlated liana species composition summarized with PCoA with the functional composition summarized by PCA, considering the species mean values of traits at the plot level. We tested the relationship between ordination axes and the environmental gradients. Liana species composition was highly correlated with functional composition. Taxonomic (PCoA) and functional (PCA) composition were strongly associated with the hydrological gradient, with a slight impact of forest disturbance on functional composition. Species at valley areas had higher stomata size and higher proportions of self-supporting xylem than plateau. Differently, lianas on plateaus invest more in fast-growing leaves (higher SLA), although with a higher wood density. Our study reveals that lianas use different functional solutions in dealing with each end of the hydrological gradient and that the relationships between habitat preferences and traits explain lianas species distributions not straightforwardly as previously found for trees.

Evaluation of Fuel Quality, Throughput Rate and Energy Consumption During Non-Industrial Wood Chip Production with Three PTO Driven Chippers

Physical wood chip quality is essential for failure-free and low emission combustion in small-scale boilers ≤100 kW. In Bavaria, these furnaces are often operated by farmers or private forest owners that produce their own fuels using small to medium sized PTO-driven chippers. As secondary fuel processing steps such as industrial screening are usually too expensive for private forest owners, the selection of suitable raw materials and process parameters to directly produce high quality fuels during chipping are deemed especially relevant for this user group. In the present study, three commonly used small-scale chippers ≤150 kW, i. e. a drum, a spiral and a disc chipper where evaluated in terms of fuel quality, throughput rate and energy consumption during wood chip production. Chipping was done using stem wood of European beech and Norway spruce. Machine settings were the ones recommended by the chipper manufactures for the production of high quality fuels. Additional chipping variants included the use of different raw materials such as crown residues of European willow and varying machine settings including blunt knives, increasing spiral cut length, large screen mesh sizes or increased PTO speeds. Representive wood chip samples were taken after each trial and analysed in their physical fuel properties according to international standards for solid biofuels but also using a continuously measuring image analysis device to determine particle length and particle shape. For all three mobile chippers, wood chips with the particle size class »P31s« according to the revised ISO 17225-4:2021 could be produced when stem wood was used as assortment. Fine content of chips, i. e. particles ≤3.15 mm, was lowest for the spiral chipper and increased for the drum and disc chipper, especially when blunt knives or narrow screen meshes were used for chipping. At the same time, blunt knives increased the particle shape factor (PSF) of the bulk materials indicating a rather broken particle surface structure compared to clean cut particles. Throughput rate decreased and energy consumption increased when fuels with small particle size were produced, e. g. when narrow screen meshes or narrow chipping spirals were applied. This trend was particularly pronounced when blunt knives were used for chipping due to grinding of the material. All three chippers could be recommended for the production of high quality fuels for small-scale boilers when suitable machine settings and raw materials are applied for chipping.

Economic feasibility of obtaining wood phytomass through accelerated cultivation of pine wood on postagrogenic lands

The paper examines economic efficiency of obtaining wood biomass through accelerated cultivation of pine on postagrogenic lands of the Leningrad Region of Northwest Russia. In experimental pine plantations, we selected model trees and calculated the stem wood biomass of 11-year old stands with different stem densities. Assessments of the economic efficiency of the production of wood chips from pine wood grown on postagrogenic lands were based on a set of machines and mechanisms, consumables and wages. A break-even point was determined for the production of wood chips in plantations with different stem densities. In the variant with a stand density of 2900 trees per hectare, it is possible to make a profit, because a break-even point was obtained for the investments made. Pine stands of such density can be taken as a prototype, when creating and growing short rotation plantations. Based on the results of the study, it is possible to predict a further increase in pine wood biomass in a plantation on post-agrogenic soils. On postagrogenic lands, marketable wood pulp can be obtained within a short period of time; thus such lands will be involved in an economic turnover.

Resistance of Pinus Sibirica clones to insect conobionts in the Yelbashinsky nursery of JSC «Berdsky forestry» in Novosibirsk region

The inter-clonal variability of Siberian cedar in resistance to insect conobionts was studied. The authors revealed that the main pests of cones and seeds are cone moth Dioryctria abietella Schiff and giant cone moth Eupithecia abietaria Goeze in the archives of plus-tree clones of Novosibirsk region (Yelbashinsky Nursery of JSC «Berdsky forestry», Iskitimsky district). The moth’s infestation of buds was 23.4%, and the infestation of buds by the moth was 2.0%. Selection of cedar for resistance to cone moths can be an effective way to increase yield at breeding and seed production facilities of this breed based on the study of inter-clonal variability in the degree of cone moth damage and other traits. Selection for resistance to cone moth disease will not significantly change stem wood produc- tivity due to the absence of a reliable interclonal correlation between the degree of cone damage and tree size. The authors described the result of the findings of the inter-clone correlation, consisting of a significant positive correlation between cone size and «granularity» and stem height and diameter. This result was against the background of the complete absence of any correlation between cone damage by conobionts and tree and cone size. The authors also concluded that selection for stem wood productivity in cedar would be accompanied by an increase in cone size and «granularity» (and vice versa), while selection for resistance to conobionts will not lead to significant changes in other vegetative and generative traits.

A Band Model of Cambium Development: Opportunities and Prospects

More than 60% of tree phytomass is concentrated in stem wood, which is the result of periodic activity of the cambium. Nevertheless, there are few attempts to quantitatively describe cambium dynamics. In this study, we develop a state-of-the-art band model of cambium development, based on the kinetic heterogeneity of the cambial zone and the connectivity of the cell structure. The model describes seasonal cambium development based on an exponential function under climate forcing which can be effectively used to estimate the seasonal cell production for individual trees. It was shown that the model is able to simulate different cell production for fast-, middle- and slow-growing trees under the same climate forcing. Based on actual measurements of cell production for two contrasted trees, the model effectively reconstructed long-term cell production variability (up to 75% of explained variance) of both tree-ring characteristics over the period 1937−2012. The new model significantly simplifies the assessment of seasonal cell production for individual trees of a studied forest stand and allows the entire range of individual absolute variability in the ring formation of any tree in the stand to be quantified, which can lead to a better understanding of the anatomy of xylem formation, a key component of the carbon cycle.

Genetic Architecture of Multiphasic Growth Covariation as Revealed by a Nonlinear Mixed Mapping Framework

Trait covariation during multiphasic growth is of crucial significance to optimal survival and reproduction during the entire life cycle. However, current analyses are mainly focused on the study of individual traits, but exploring how genes determine trait interdependence spanning multiphasic growth processes remains challenging. In this study, we constructed a nonlinear mixed mapping framework to explore the genetic mechanisms that regulate multiphasic growth changes between two complex traits and used this framework to study stem diameter and stem height in forest trees. The multiphasic nonlinear mixed mapping framework was implemented in system mapping, by which several key quantitative trait loci were found to interpret the process and pattern of stem wood growth by regulating the ecological interactions of stem apical and lateral growth. We quantified the timing and pattern of the vegetative phase transition between independently regulated, temporally coordinated processes. Furthermore, we visualized the genetic machinery of significant loci, including genetic effects, genetic contribution analysis, and the regulatory relationship between these markers in the network structure. We validated the utility of the new mapping framework experimentally via computer simulations. The results may improve our understanding of the evolution of development in changing environments.

Solving the problem of optimizing the cutting of wood whips with curvature

Stem wood, obtained from the cuttings of care in low-forest areas is of low quality. Such wood has a number of vices, one of which is simple curvature, which has impact on the voluminous and commercial output of round timber. Reducing this influence can be achieved through high-quality bucking. Therefore, the purpose of the work presented is to increase the volume and commercial output of round timber harvested in low-forest areas. The developed technique using computers allows to solve the tasks of modeling the shape of wood whips and logs using multi-critical optimization and bucking whips having curvature. The use of the proposed technique allows for results adequate to the real production conditions, as evidenced by the methods of decision-making used. Scientific research and theoretical developments, taking into account the formed database, allowed to search for the optimal scheme of cutting when bucking round timber, performed according to the algorithm based on the busting of acceptable variants using modern theory of graphs and matrixes. As a result, the developed program will reduce the time for data formation, guarantee the accuracy of the results, the program easily adapts to natural and production conditions and will expand the possibilities for Computer-aided design.

VARIATION OF THE TECHNOLOGICAL PROPERTIES OF WOOD FROM Ochroma pyramidale IN THE LONGITUDINAL AND RADIAL SENSE OF THE SLEW

The work aimed to characterize the wood of the species Ochroma pyramidale in the longitudinal and radial direction of the tree. For the study, five six-year old trees were used. Discs were removed at different heights of the stem. The samples were obtained from each disk in different regions between the pith and bark. The preparation and the anatomical analysis of the permanent and temporary slides, chemical analyzes, and basic density measure of the stem wood were carried out according to technical standards. As a result, it was observed that the highest averages for pore diameter and fiber length were found in the region close to the bark at all heights. Regarding to the rays, it was noted that there was an interaction between the longitudinal x radial factors for most of the parameters evaluated, except for the width of the rays. For fiber lumen diameter and vessel length, the same trend line was found, the highest average observed in the region close to the pith. In the chemical analyzes, it was possible to observe that there was no significant difference in the longitudinal direction of the wood except for solubility in cold water. For basic density, there was an increase in the region closer to the pith compared to the region closer to the bark. However, in relation to the longitudinal position of the bole, the highest values were found at the base of the bole. It could be seen that the Ochroma pyramidale species has potential use for products linked to thermal and acoustic insulation, production of particleboards and pulp and paper production.