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Studies on the genetic diversity of coffee trees are important, considering their role in the maximization of productivity and quality. However, the success of a breeding program depends on the existence of genetic variability in the population under study. Our study aimed to evaluate the genetic diversity of the morpho-agronomic and anatomical leaf traits of different cultivars of Coffea arabica grown in the Gorongosa mountain region, in the area of Gorongosa National Park, Mozambique. The experiment assessed nine coffee cultivars based on their morpho-agronomic and anatomical traits. The plagiotropic branch diameter, leaf dry mass, leaf mass per area, number of epidermal cells + stomata, and stomatal form indicated differences among the studied cultivars. Among the nine C. arabica cultivars grown in the mountainous region of Gorongosa National Park, Mozambique, low genetic variability in morpho-agronomic traits was detected, while the genetic variability in leaf anatomical traits was higher. The nine cultivars were segregated into two groups, one consisting of Catucaí Amarelo 2SL and Catuaí Vermelho IAC 81, and the second consisting of Catuaí Amarelo IAC 39, Catucaí Vermelho 19/8, Acauã, Catucaí 785-15, Costa Rica, Catimor 128, and Catuaí Vermelho IAC 44. The cultivar segregation into the two groups indicated that the morpho-anatomical traits can be considered during the selection stages in breeding programs. [ABSTRACT FROM AUTHOR]

Introduction: Soybean stem diameter (SD) and branch diameter (BD) are closely related traits, and genetic clarification of SD and BD is crucial for soybean breeding. Methods: SD and BD were genetically analyzed by a population of 363 RIL derived from the cross between Zhongdou41 (ZD41) and ZYD02878 using restricted two-stage multi-locus genome-wide association, inclusive composite interval mapping, and three-variance component multi-locus random SNP effect mixed linear modeling. Then candidate genes of major QTLs were selected and genetic selection model of SD and BD were constructed respectively. Results and discussion: The results showed that SD and BD were significantly correlated (r = 0.74, P < 0.001). A total of 93 and 84 unique quantitative trait loci (QTL) were detected for SD and BD, respectively by three different methods. There were two and ten major QTLs for SD and BD, respectively, with phenotypic variance explained (PVE) by more than 10%. Within these loci, seven genes involved in the regulation of phytohormones (IAA and GA) and cell proliferation and showing extensive expression of shoot apical meristematic genes were selected as candidate genes. Genomic selection (GS) analysis showed that the trait-associated markers identified in this study reached 0.47-0.73 in terms of prediction accuracy, which was enhanced by 6.56-23.69% compared with genome-wide markers. These results clarify the genetic basis of SD and BD, which laid solid foundation in regulation gene cloning, and GS models constructed could be potentially applied in future breeding programs. [ABSTRACT FROM AUTHOR]

Studies on the genetic diversity of coffee trees are important, considering their role in the maximization of productivity and quality. However, the success of a breeding program depends on the existence of genetic variability in the population under study. Our study aimed to evaluate the genetic diversity of the morpho-agronomic and anatomical leaf traits of different cultivars of Coffea arabica grown in the Gorongosa mountain region, in the area of Gorongosa National Park, Mozambique. The experiment assessed nine coffee cultivars based on their morpho-agronomic and anatomical traits. The plagiotropic branch diameter, leaf dry mass, leaf mass per area, number of epidermal cells + stomata, and stomatal form indicated differences among the studied cultivars. Among the nine C. arabica cultivars grown in the mountainous region of Gorongosa National Park, Mozambique, low genetic variability in morpho-agronomic traits was detected, while the genetic variability in leaf anatomical traits was higher. The nine cultivars were segregated into two groups, one consisting of Catucaí Amarelo 2SL and Catuaí Vermelho IAC 81, and the second consisting of Catuaí Amarelo IAC 39, Catucaí Vermelho 19/8, Acauã, Catucaí 785-15, Costa Rica, Catimor 128, and Catuaí Vermelho IAC 44. The cultivar segregation into the two groups indicated that the morpho-anatomical traits can be considered during the selection stages in breeding programs.

Ivorian cashew (Anacardium occidentale L.) orchards are essentially comprised of unselected trees of diverse origins and characterized by a very low yield per hectare. In these orchards, potentially high-yielding trees have been identified. Vegetative propagation remains the most appropriate technique for the regeneration of these trees. Air layering is the regeneration technique used for a number of wood species that are difficult to root through clonal propagation. The objective of this study was to set up a regeneration protocol using the layering technique. Specifically, we evaluated the effect of the substrates, diameter class, and indole butyric acid concentration on the rooting percentage and survival of hardened plants. For this purpose, two diameter classes 5-8 mm and 8-12 mm, four substrates (sawdust, rice chip, coco peat, and coffee integument), two concentrations of indole butyric acid (2.5 and 5 mg/L) and one control (no indole butyric acid solution). were tested. Rooting percentages of 88.09, 79.36, and 61.90 were obtained with sawdust, rice chip, and coco peat respectively. No roots were observed on the coffee integument. Diameter class 8-12 mm promoted the most significant percentage of survival (89.41%) and rooting (85.18%). The concentration of 5 mg/L favored the induction of the greatest number of roots (30.79). The specific percentage of possible survival in the field of the weaned layer was above 80%. Branches with 8-12 mm diameter treated with indole butyric acid 5 mg/L in sawdust induced was the optimum treatment combination for cashew nut layering propagation in Cote d'Ivoire. [ABSTRACT FROM AUTHOR]

The effect of pruning on tree development and the potential structure of wood assortments was investigated in the poplar Populus × canadensis clone “I-214”. The study was carried out in a permanent sample plot within a poplar plantation established in 2006, in the area of the “Vojvodinašume” Public Company, within the “Gornje Potamišje” Forest Management Unit (Republic of Serbia). Pruning was performed on a total of 325 trees at different stem heights and a total of 13,186 branches were pruned. The average number of pruned branches per tree at the stem height of 5 m was 36, while it was 40 at the stem height of 6 m and 46 at the stem height of 7 m. The average diameter of pruned branches was 1.7 cm. The results showed that there are no significant differences in diameters at breast height between pruned and unpruned trees after two different intensities of pruning. Our results showed that pruning do not impact the long-term growth performance in poplar clone “I-214”, while remarkably improving the quality and economic value of wood assortments obtained from pruned trees.

Korean pine (Pinus koraiensis Sieb. et Zucc.) is the most important forest vegetation in northeast China. The timber quality of this tree species is largely driven by branch growth and distribution within the crown. Thus, developing branch diameter and length models, especially those that include competition indices, is essential. A total of 48 Korean pine trees were selected to conduct destructive measurements of branch characteristics. This was carried out on all live branches, and a branch diameter and length model was developed. Various indices, including the absolute depth into the branch base (DINC) from tree tip, were used. The equation with the largest Radj2 and smallest root mean square error (RMSE) values was selected as the best model. Each parameter from the best model was reparameterized to the tree variables and competition indices. Finally, the branch diameter model that included diameter at the breast height (DBH), tree height (HT), and the crown length index (CLI), and the branch length model that included DBH and HT exhibited the best performance. The Radj2 and RMSE values were 0.42 and 4 mm, respectively, for the branch diameter model, and 0.77 and 63 cm, respectively, for the branch length model. Branch diameter and length increased as DBH increased and decreased as HT increased. Furthermore, branch diameter decreased as the CLI increased. [ABSTRACT FROM AUTHOR]

The branchwood of fruit trees is being promoted to supplement the fiber material for paper manufacturing in China. This study was conducted to investigate the fiber morphology of walnut branchwood, and to highlight its potential utilizations in papermaking. The effects of the branch diameter, branching level, and tension wood on the fiber morphology were also investigated. The results showed that approximately 65% of the fibers were longer than 900 μm, 95% of the fibers had a slenderness ratio greater than 40, and 67% of the fibers had a Runkel ratio less than 1. It is evident from the results that the fiber morphology of walnut branchwood is reasonably good for paper manufacturing. However, the diameter of the branch does not provide reliable information to predict the fiber morphometrics. In addition, the branching level and tension wood are not very helpful in the screening of fiber raw materials. [ABSTRACT FROM AUTHOR]

Diagnostic testing to detect forest pathogens requires the collection of physical samples from affected trees, which can be challenging in remote or rugged environments. As an alternative to traditional ground-based sampling at breast height by field crews, we examined the feasibility of aerially sampling and testing material collected from upper canopy branches using a small unoccupied aerial system (sUAS). The pathogen of interest in this study is Ceratocystis lukuohia, the fungal pathogen responsible for Ceratocystis wilt of ‘ōhi‘a, a vascular wilt disease which has caused widespread mortality to ‘ōhi‘a in native forests across the state of Hawai‘i. To characterize the minimum branch diameter needed to successfully detect the pathogen of interest in infected trees, we tested 63 branch samples (0.8–9.6 cm in diameter) collected from felled trees inoculated with C.lukuohia on Hawai‘i Island. Subsequently, we aerially sampled branches from ten symptomatic ‘ōhi‘a (Metrosideros polymorpha) trees using two different branch sampling systems, the Flying Tree Top Sampler from ETH Zurich and the new Kūkūau branch sampler system introduced in this work, producing 29 branch samples with a maximum diameter of 4.2 cm and length of >2 m. We successfully detected the target fungal pathogen from the collected branches and found that branch diameter, leaf presence and condition, as well as wood moisture content are important factors in pathogen detection in sampled branches. None of the smallest branch samples (those C.lukuohia, while 77% of the largest diameter branch samples (5–10 cm) produced positive results. The Kūkūau branch sampler system is capable of retrieving branches up to 7 cm diameter, providing important capacity for pathogenic research requiring larger diameter samples for successful diagnostic testing. Inconclusive and/or non-detection laboratory results were obtained from sample materials that were either too desiccated or from a branch with asymptomatic leaves, suggesting there is an optimal temporal window for sampling.

Cutting mechanisms and the cutting force are the focus of this article. The cutting force can be determined theoretically or mathematically by statistical analysis. In this work, the cutting speed was compared when changing the diameter of the test wood and when using the three types of angular geometry of delimbing knives. Experimental measurements were conducted on a self-designed experimental pneumatic stand. Empirical relationships and values from the scientific literature were used to determine the input parameters. Based on a regression analysis, conclusions were drawn relative to factors affecting the process of delimbing. The angular geometry of the delimbing knife plays a significant role in the delimbing process. The thicker the knife, the higher the energy consumption in the cutting process and the poorer the quality of the cutting surface of the wood. The quality of chipless separation timber was found to depend on the cutting speed, and the optimal speed was 2.0 m s-1. [ABSTRACT FROM AUTHOR]

Introduction: Soybean stem diameter (SD) and branch diameter (BD) are closely related traits, and genetic clarification of SD and BD is crucial for soybean breeding., Methods: SD and BD were genetically analyzed by a population of 363 RIL derived from the cross between Zhongdou41 (ZD41) and ZYD02878 using restricted two-stage multi-locus genome-wide association, inclusive composite interval mapping, and three-variance component multi-locus random SNP effect mixed linear modeling. Then candidate genes of major QTLs were selected and genetic selection model of SD and BD were constructed respectively., Results and Discussion: The results showed that SD and BD were significantly correlated (r = 0.74, P < 0.001). A total of 93 and 84 unique quantitative trait loci (QTL) were detected for SD and BD, respectively by three different methods. There were two and ten major QTLs for SD and BD, respectively, with phenotypic variance explained (PVE) by more than 10%. Within these loci, seven genes involved in the regulation of phytohormones (IAA and GA) and cell proliferation and showing extensive expression of shoot apical meristematic genes were selected as candidate genes. Genomic selection (GS) analysis showed that the trait-associated markers identified in this study reached 0.47-0.73 in terms of prediction accuracy, which was enhanced by 6.56-23.69% compared with genome-wide markers. These results clarify the genetic basis of SD and BD, which laid solid foundation in regulation gene cloning, and GS models constructed could be potentially applied in future breeding programs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Yang, Chen, Liu, Zhang, Xiong, Yu, Yu, Wang, Song and Qiu.)

Objectives: Laboratory studies have yielded important insights into primate locomotor mechanics. Nevertheless, laboratory studies fail to capture the range of ecological and structural variation encountered by free‐ranging primates. We present techniques for collecting kinematic data on wild primates using consumer grade high‐speed cameras and demonstrate novel methods for quantifying metric variation in arboreal substrates. Materials and methods: These methods were developed and applied to our research examining platyrrhine substrate use and locomotion at the Tiputini Biodiversity Station, Ecuador. Modified GoPro cameras equipped with varifocal zoom lenses provided high‐resolution footage (1080 p.; 120 fps) suitable for digitizing gait events. We tested two methods for remotely measuring branch diameter: the parallel laser method and the distance meter photogrammetric method. A forestry‐grade laser rangefinder was used to quantify substrate angle and a force gauge was used to measure substrate compliance. We also introduce GaitKeeper, a graphical user interface for MATLAB, designed for coding quadrupedal gait. Results: Parallel laser and distance meter methods provided accurate estimations of substrate diameter (percent error: 3.1–4.5%). The laser rangefinder yielded accurate estimations of substrate orientation (mean error = 2.5°). Compliance values varied tremendously among substrates but were largely explained by substrate diameter, substrate length, and distance of measurement point from trunk. On average, larger primates used relatively small substrates and traveled higher in the canopy. Discussion Ultimately, these methods will help researchers identify more precisely how primate gait kinematics respond to the complexity of arboreal habitats, furthering our understanding of the adaptive context in which primate quadrupedalism evolved. [ABSTRACT FROM AUTHOR]

Detailed 3D plant architectural data have numerous applications in plant science, but many existing approaches for 3D data collection are time-consuming and/or require costly equipment. Recently, there has been rapid growth in the availability of low-cost, 3D cameras and related open source software applications. 3D cameras may provide measurements of key components of plant architecture such as stem diameters and lengths, however, few tests of 3D cameras for the measurement of plant architecture have been conducted. Here, we measured Salix branch segments ranging from 2–13 mm in diameter with an Asus Xtion camera to quantify the limits and accuracy of branch diameter measurement with a 3D camera. By scanning at a variety of distances we also quantified the effect of scanning distance. In addition, we also test the sensitivity of the program KinFu for continuous 3D object scanning and modeling as well as other similar software to accurately record stem diameters and capture plant form (6 mm, Asus Xtion may provide a novel method for the collection of 3D data on the branching architecture of woody plants. Improvements in camera measurement accuracy and available software are likely to further improve the utility of 3D cameras for plant sciences in the future.

The effects of branch pruning device Stihl HT-75 were researched on sample plots in FA Kupinovo and FA Klenak, in poplar plantations of Populus×euramericana 'I-214', Populus×euramericana 'M1' and Populus deltoides of different planting spaces and different ages. The analysed factors were: pruning method, site conditions, number of pruned branches, pruning height, branch diameter, etc. Time measurement was performed by the flow method, and the required number of measurements was calculated by variation statistics. The results of the analysis of variance show the statistical significance of the differences between pruning times of different clone species, different planting spaces and different plantation ages. The results of the analysis of variance and statistical tests show that there are no statistically significant differences between the average time of poplar pruning in plantations of the same age and different planting spaces. The correlation of branch pruning time and the number of pruned branches is represented by the power function model, which according to the results of the regression analyses, is the best representation of the nature of this dependence. Exponential function represents the correlation of the average diameter of pruned branches and the time of pruning. Also, there is a correlation of the average diameter of pruned branches and fuel consumption. Pruning time of poplar trees increases with the increase of the average diameter of pruned branches.

In the process plant, random vibration with shell mode excited by the turbulence generated at tee connection might cause problems such as piping damage. Author proposed a new evaluation index in the previous work to evaluate the random vibration with shell mode at tee connection downstream and the adequacy of the index was confirmed by the experiment with 1.5 inch × 4 inch piping system with 45 deg combining tee connection so as to confirm the adequacy of the index proposed in the previous work. This paper presents the experimental study results to investigate the effects of branch size and combining angle. In the experiment the branch area ratio to the main pipe area were varied from 0.0146 to 1.00, and two combining angles, 90 and 45 degrees were examined. As a result, it was confirmed the proposed index could evaluate vibration stress adequately for wide range of the branch pipe area ratio. And the vibration stress for the piping system with 90 deg connection is around 1.4 times of that with 45 deg tee connection.

Growth on one branch is suppressed in proportion to pruning severity, resulting in a predictable reduction in branch:trunk diameter (aspect) ratio. However, little is known about response to pruning multiple branches. Several of the largest branches on live oak (15.3 cm trunk diameter) were pruned with four severities (0%, 25%, 50%, and 75%), then branch, nearby stem, and trunk diameter were measured for five subsequent years. Rate of trunk diameter increase five years after pruning was greatest for trees pruned with the 25% severity. Aspect ratio on all three pruned and measured branches decreased with time after pruning, pruning severity, and increasing height in the crown. Mean aspect ratio ceased declining between three and five years after pruning. The decrease in aspect ratio over time and with increasing severity on pruned branches was less pronounced in the lower crown than in the upper crown. Smaller change in aspect ratio on pruned branches in the lower crown suggests that when structurally pruning trees, branches in the lower crown may require a higher pruning severity to effect the same change in aspect ratio as upper branches. [ABSTRACT FROM AUTHOR]

Detailed 3D plant architectural data have numerous applications in plant science, but many existing approaches for 3D data collection are time-consuming and/or require costly equipment. Recently, there has been rapid growth in the availability of low-cost, 3D cameras and related open source software applications. 3D cameras may provide measurements of key components of plant architecture such as stem diameters and lengths, however, few tests of 3D cameras for the measurement of plant architecture have been conducted. Here, we measured Salix branch segments ranging from 2-13 mm in diameter with an Asus Xtion camera to quantify the limits and accuracy of branch diameter measurement with a 3D camera. By scanning at a variety of distances we also quantified the effect of scanning distance. In addition, we also test the sensitivity of the program KinFu for continuous 3D object scanning and modeling as well as other similar software to accurately record stem diameters and capture plant form (<3 m in height). Given its ability to accurately capture the diameter of branches >6 mm, Asus Xtion may provide a novel method for the collection of 3D data on the branching architecture of woody plants. Improvements in camera measurement accuracy and available software are likely to further improve the utility of 3D cameras for plant sciences in the future. [ABSTRACT FROM AUTHOR]

By using the branch analysis data of 955 standard branches from 60 sampled trees in 12 sampling plots of Pinus koraiensis plantation in Mengjiagang Forest Farm in Heilongjiang Province of Northeast China, and based on the linear mixed-effect model theory and methods, the models for predicting branch variables, including primary branch diameter, length, and angle, were developed. Considering tree effect, the MIXED module of SAS software was used to fit the prediction models. The results indicated that the fitting precision of the models could be improved by choosing appropriate random-effect parameters and variance-covariance structure. Then, the correlation structures including complex symmetry structure (CS), first-order autoregressive structure [AR(1)], and first-order autoregressive and moving average structure [ARMA(1,1)] were added to the optimal branch size mixed-effect model. The AR(1) improved the fitting precision of branch diameter and length mixed-effect model significantly, but all the three structures didn't improve the precision of branch angle mixed-effect model. In order to describe the heteroscedasticity during building mixed-effect model, the CF1 and CF2 functions were added to the branch mixed-effect model. CF1 function improved the fitting effect of branch angle mixed model significantly, whereas CF2 function improved the fitting effect of branch diameter and length mixed model significantly. Model validation confirmed that the mixed-effect model could improve the precision of prediction, as compare to the traditional regression model for the branch size prediction of Pinus koraiensis plantation. [ABSTRACT FROM AUTHOR]

• Introduction: Branch size and branch status (dead or alive) are important characteristics closely related to tree growth and wood quality. The aim of this study was to design models for the diameter and status of branches in Atlas cedar ( Cedrus atlantica Manetti). • Material and methods: The models were developed from data collected on a set of 32 trees with a wide range of heights (from 3 to 36 m), girths (from 13 to 226 cm), and ages (from 20 to 95 years). A single general segmented model was designed for both whorl and interwhorl branch diameter, taking into account the tree and annual growth unit random effects. • Results: The model's 'potential x reducer' form describes the maximum branch diameter profile along the tree and the acrotonic gradient observed in annual shoots. The diameter and status of every branch were modeled based on the vertical position on the trunk and on the height of the base of the living crown. The tree diameter and the branch diameter were used as additional explanatory variables in the branch diameter model and the branch status model, respectively. • Conclusion: The model structure is sufficiently general to be suited after re-parameterization for many coniferous species with interwhorl branches such as Spruces, Firs, and Larches. [ABSTRACT FROM AUTHOR]

Abstract: A total of 83 trees were sampled in three regions of Eastern Canada in order to model branch characteristics (number of branches per annual shoot, branch insertion angle and diameter) using linear mixed-effects models. Differences in branch characteristics according to branch type (pseudo-whorl at annual shoot apical end (PWA) versus pseudo-whorl between shoot apical ends (PWB)) were also studied. The number of both PWA and PWB branches are proportional to annual shoot length, whereas the number of PWB branches also decreases with tree age. Insertion angle was mainly driven by annual shoot number from apex (branch age). The diameter models showed the most complexity with branch vertical position and tree size (DBH and total height) among the statistically significant variables. Region and plot random effects were minimal compared with tree and annual shoot levels. Tree-level random effects were significant for every model and might be a symptom of genetic control over the number of branches and, to a small extent, branch diameter. Interaction between insertion angle and diameter is relatively strong because all the models using them as independent variables (except for the model of insertion angle for PWB branches) showed better fit statistics. These results lead us to believe that tree-, annual shoot- and branch-level variables should be further explored in order to better understand branch dynamics. [Copyright &y& Elsevier]

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The aim of this study was to investigate the impacts of elevated carbon dioxide (CO 2 ) and temperature on the establishment, growth and mortality of the branches of Scots pine ( Pinus sylvestris L). In 1997, 16 young trees were individually enclosed in chambers, in eastern Finland, for a period of 5 years (1997–2001), in an environment that simulated the future climate for the region. There were four replicates of each treatment, including combinations of ambient and elevated CO 2 and temperature. Measurements were carried out on the establishment of new branches, branch diameter growth and branch mortality. Elevated temperature and elevated CO 2 had no positive effect on the number of branches that established each year or branch diameter growth. They were, instead, related to tree height growth and stem diameter growth, respectively. However, elevated CO 2 and temperature caused an increase in branch mortality. [ABSTRACT FROM AUTHOR]

This study examined branch diameter, number of whorls, and number of branches in the lower 2 m of the stems of white spruce growing in pure stands and in mixture with a range of densities of trembling aspen. Data were collected from two study sites located north of Big River Saskatchewan, which were regenerated following clearcutting in 1992 and thinned in 1996 to five aspen densities and two spruce densities. Results show significant decreases in spruce diameter at breast height (DBH), height, live crown ratio, maximum branch diameter in the lower 2 m, average branch diameter in the whorl closest to 1 m, and increases in tree slenderness with increases in aspen density. Increasing spruce density reduced the number of live branches and number of live branch whorls in the lower 2 m. Maximum branch diameter in the whorl closest to 1 m was influenced by both aspen and spruce density, with a significant interaction term resulting from effects of intraspecific competition being evident for aspen densities of 1500 stems ha−1 or lower. DBH and slenderness explained more than 49% of the variation in spruce crown width, maximum branch diameter in the lower 2 m, maximum live branch diameter in the whorl closest to 1 m, and average live branch diameter in the whorl closest to 1 m. DBH explained more variation in crown width and branch diameter than slenderness. This study demonstrates that growing spruce in mixture with aspen can lead to reductions in branch size and that early thinning to low aspen densities could lead to increases in size of knots and associated reductions in wood quality, particularly when spruce densities are low. [ABSTRACT FROM AUTHOR]

Background and Objectives: The study aimed to determine the changes of the main stem and branch parameters of Norway spruce (Picea abies (L.) H. Karst) trees under different stand densities. More specifically, the objective was to develop the models for the determination of branch diameter in 0–6 m log from root collar, taken as one of the parameters directly influencing the stem quality. The study continues a piece of research on stem and branch parameters' responses to different stand density (SD) in the plantations of coniferous tree species in Lithuania. Materials and Methods: The following key parameters were measured in this study: total tree height, diameter at breast height, height to the lowest live branch, height to the lowest dead branch, and diameter of all branches in 0–6 m log. The linear regression models to predict branch diameter in 0–6 m log were developed based on stand density (SD), tree characteristics (tree diameter at breast height, DBH; and tree height, H) and other related stem and branch parameters. Results and Conclusions: Directly measured tree DBH, branch diameters and number of branches in 0–6 m log decreased significantly with the increasing SD. In the 0–6 m log, the branch diameter and the diameter of the thickest branch were identified as the main parameters related to stem quality. The best fitted models, developed including SD, tree DBH, branch diameter, and diameter of the thickest branch in 0–3 m log, can be proposed as a predictor for stem-wood quality for Norway spruce in hemiboreal forest zone. [ABSTRACT FROM AUTHOR]

Background and Objectives: The aim of this study was to determine the effects of different stand densities and thinning regimes on stem quality parameters, mainly branch characteristics, of Scots pine (Pinus sylvestris L.) trees. The study provides some input to the discussion about Scots pine stem quality responses to different forest management practices in relatively young stands. Materials and Methods: Total tree height, height to the lowest live and dead branch, diameter at breast height (DBH), and diameter of all branches from the whorls located up to 6 m from the ground were measured. The linear regression models to predict branch diameter, as the main parameter for the stem quality assessment, were developed based on stand density and stem parameters. Results and Conclusions: DBH, branch diameter and number of branches up to 6-m stem height were significantly higher in the stands with the lowest density. These stem parameters showed a relatively clear downward trend from the lowest to the highest stand densities. The main identified variables which significantly affected stem quality, were branch diameter and diameter of the thickest branch in the bottom part of the stem, at least up to 3-m stem height. For practical use, the best fitted model was estimated when stand density, DBH, and branch diameter up to 3-m height were included in a single equation. The developed model for branch diameter could be used as a forest management tool for managing stem-wood quality. [ABSTRACT FROM AUTHOR]