Numerous studies have reported the beneficial effects of natural environments on human health and wellbeing. Virtual games may offer a practical approach to experience the illusion of being in a natural setting for those with limited access to nature. This study presents an evaluation of a nature-based virtual environment application to modulate the participant’s affective and psychological state. We developed a game-based virtual therapy using the Unity 3D game engine by implementing forest therapy activities and designing the forest environment like a real-life forest. Eight healthy adults participated in this study and were observed remotely. The participants’ mood states before and after the game were evaluated using the Profile of Mood States (POMS). In addition, the satisfaction and usability of the game-based virtual forest were assessed using the Game-User Experience Satisfaction Scale and System Usability Scale, respectively. The results revealed that participants experienced significantly improved moods (p < 0.05) and decreased stress levels (p < 0.05) after playing the game. Moreover, the results indicated multiple positive correlations between the game experience and immersion subscales, revealing that audio and visual aesthetics offered an environment for users to feel more immersed. The study suggests using virtual forest games to promote positive mood and mental health. Full article

This study aimed to determine the optimal approach for estimating stem diameter distributions (SDD) from airborne laser scanning (ALS) data using point cloud metrics (M_als), a canopy height model (CHM) texture metrics (M_tex), and a combination thereof (M_comb). We developed area-based models (i) to classify SDD modality and (ii) predict SDD function parameters, which we tested for 5 modelling techniques. Our results demonstrated little variability in the performance of SDD modality classification models (mean overall accuracy: 72%; SD: 2%). Our best SDD function parameter models were generally fitted with M_comb, with R² improvements up to 0.25. We found the variable Correlation, originating from M_tex, to be the most important predictor within M_comb. Trends in the performance of the predictor groups were mostly consistent across the modelling techniques within each parameter. Using an Error Index (EI), we determined that differentiating modality prior to estimating SDD improved the accuracy of estimates for bimodal plots (~12% decrease in EI), which was trivially not the case for unimodal plots (<1% increase in EI). We concluded that (i) CHM texture metrics can be used to improve the estimate of SDD parameters and that (ii) differentiating for modality prior to estimating SSD is especially beneficial in stands with bimodal SDD. Full article

How trees allocate their biomass among different components has important implications for their survival and growth and ecosystem carbon cycling. Data on the distribution pattern and dynamics of tree biomass are essential for fully exploiting forest carbon sequestration potential and achieving the goal of carbon neutralization. However, there has not been enough research to-date on tree biomass spatial allocation and temporal dynamics in different site qualities at specific tree species scales. This study aimed to evaluate the biomass allocation patterns within tree components of Chinese fir and to examine how they are affected by tree age and site quality. A total of 87 trees were destructively sampled and measured for stem, branch, leaf, bark and root biomass. The biomass proportion difference of tree components in different age stages (8-40 years) was analysed, and the influence process of tree age and site quality on biomass allocation was examined. Our results indicate that the biomass allocation varied with tree age and was also affected by site quality. Stem biomass accounted for the largest proportion of total tree biomass, followed by leaf, root, branch and bark biomass in young forests, and it was followed by root, bark, branch and leaf biomass in other age groups. The biomass proportion of each component all nonlinearly changed with tree age. The proportion of stem biomass increased with increasing tree age, and the biomass proportion of branches and leaves decreased with increasing tree age. The proportion of root biomass first increased and then decreased with tree age, while the bark biomass proportion first decreased and then increased with increasing tree age. Site quality had a positive effect on the biomass proportion of stems but a negative effect on the biomass proportion of branches and bark. The interaction of tree age and site quality also had a significant effect on the proportion of stem biomass as well as root biomass. Therefore, to obtain accurate estimates of Chinese fir forest biomass and carbon stocks, age-specific changes and the influence of site conditions on it need to be considered. Full article

Wood logs need to be measured for size when passing through customs to verify their quantity and volume. Due to the large number of wood logs needs through customs, a fast and accurate measurement method is required. The traditional log measurement methods are inefficient, have significant errors in determining the long and short diameters of the wood, and are difficult to achieve fast measurements in complex wood stacking environments. We use a Mask R-CNN instance segmentation model to detect the contour of the wood log and employ a binocular stereo camera to measure the log diameter. A rotation search algorithm centered on the wood contour is proposed to find long and short diameters and to optimal log size according to the Chinese standard. The experiments show that the Mask R-CNN we trained obtains 0.796 average precision and 0.943 $IO{U}_{mask}$, and the recognition rate of wood log ends reaches 98.2%. The average error of the short diameter of the measurement results is 5.7 mm, the average error of the long diameter is 7.19 mm, and the average error of the diameter of the wood is 5.3 mm. Full article

Cities are composed of different types of urban obstacles such as buildings, cars, trees, hedgerows, etc [...] Full article

In recent years, the use of wood has gained social interest, leading to a global increase in its demand. Yet, this demand is often covered by the production of woods of low natural durability against biological deterioration. The main biological agents with the potential to attack the structural integrity of wood are wood-decay fungi, saproxylic beetles, termites, and marine molluscs and crustaceans. In most circumstances, fungi are the main wood-deteriorating agents. To attack the cell wall, wood-decay fungi combine a complex enzymatic mechanism with non-enzymatic mechanisms based on low-molecular-weight compounds. In some cases, the larvae of saproxylic beetles can also digest cell wood components, causing serious deterioration to wooden structures. The impact of subterranean termites in Europe is concentrated in the Southern countries, causing important economic losses. However, alien invasive species of voracious subterranean termites are expanding their presence in Europe. Wooden elements in permanent contact with marine water can be readily deteriorated by mollusc and crustacean borers, for which current preservatives lack efficacy. The natural durability of wood is defined as the inherent resistance of wood to catastrophic action by wood-destroying organisms. Besides exposure to the climate, product design and use conditions, the natural durability of wood is key to the prediction of the service life of wooden products, which can be shortened due to the impact of global change. The major wood properties involved in natural durability are related to the composition of lignin in the cell wall, the anatomy of the xylem, nutrient availability, the amount and composition of heartwood extractives, and the presence of moisture-regulating components since wood moisture content influences the establishment of wood-degrading organisms. Full article

Inappropriate fertilization management practices have led to low timber production in intensive plantation systems in China. Thus, optimized conventional or advanced fertilization management practices are needed. We aimed to quantify whether optimized furrow fertilization (FF) is comparable to advanced drip fertigation (DF) and to make recommendations regarding fertilization management strategies for poplar plantations. A completely randomized block design experiment with two fertilization methods (DF and FF) and four N application amounts (F₀: 0, F₁: 68, F₂: 113, and F₃: 158 kg N·ha⁻¹·yr⁻¹) was carried out on a Populus × euramericana cv. ‘Guariento’ plantation. Fine root biomass density (FRBD), fine root length density (FRLD), specific root length (SRL), soil total nitrogen (STN), soil inorganic nitrogen (SIN), soil ammonium (NH₄⁺-N) and nitrate nitrogen (NO₃⁻-N) were measured. The productivity increment was calculated based on tree surveys. The results showed that FRBD and FRLD decreased with the soil depth, and more than 86% was distributed within the 40 cm soil depth. FRBD, FRLD, productivity increment and soil N increased with an increasing amount of N application. DF treatments achieved 117%, 94% and 10% higher FRBD, FRLD and productivity increments, respectively, than did FF treatments. The averages of STN, SIN, NH₄⁺-N and NO₃⁻-N under FF were higher than those under DF, leading to higher concentrations of residual NO₃⁻-N in deep soil. Beneficial management practices for fine root growth were evaluated in the following order: water coupled with N > only N ≥ only water > control. FRBD was positively correlated with the productivity increment. Therefore, fine root extension to increase soil resource absorption yields greater productivity under DF treatments. Drip fertilization is recommended as a better fertilization method to greatly promote the growth of fine roots, as well as productivity and residual lower soil N for poplar plantations. Full article

European forest ecosystems are currently subject to various disturbances and shifts in land-use legacies. To be able to forecast the trends and consequences of the changes in genetic diversity following these disturbances, it is of crucial importance to understand the genetic dynamics of natural tree populations. The present study aimed at determining the extent and spatial distribution of genetic diversity in five common broadleaved tree species in Lithuania in both mature (putatively maternal) stands and in natural regeneration (juveniles) of the respective species. The genetic diversity of Quercus robur, Betula pendula, Populus tremula, Alnus glutinosa, and Fraxinus excelsior was assessed using eight nuclear microsatellite loci for each species; 417 samples of regenerating juveniles and 141 samples of putatively maternal trees were analyzed in total. The investigated populations of self-regenerating Q. robur, B. pendula, A. glutinosa, and F. excelsior juveniles showed spatially random genetic structures, while P. tremula regenerated mostly via root suckers and formed clonal groups. The genetic diversity in regenerating juveniles of all species was as high as in putatively maternal stands. The detection of adequate (substantial) genetic diversity in the studied regenerating populations of these five broadleaved tree species suggests that in Lithuania these species have a good potential to adapt to changing environmental conditions. Full article

Northern hardwoods are susceptible to a wide range of defects that can reduce the amount of sound wood with desirable qualities, such as the clear sapwood of sugar maple trees. Yet, the rate at which trees decline in quality due to the development of such defects has never been quantified in northern hardwood forests due to a dearth of repeat inventories that record the appearance of defects over time. As a result, it remains uncertain whether, and how, selection management reduces the probability of decline in quality. In this study, we quantify the rate at which trees decline in quality due to the development of defects, and we test several hypotheses regarding the influence of selection management on quality. Our results show that (1) the probability of decline in quality increases as trees grow larger; (2) crown dieback also increases the probability of decline in quality; (3) the probability of decline in quality is slightly lower in managed stands than in unmanaged stands, and (4) the probability of decline in quality increases with the mean annual temperature of the site. Finally, we combined our estimates of the probability of decline in quality with previous estimates of the probability of mortality to assess the overall risk associated with retaining trees of different species, sizes, and vigour profiles. The resulting metric can inform efforts to improve the management of northern hardwood forests by providing an integrated estimate of the risk that the value of a tree will be reduced, or eliminated, due to mortality or decline in quality. Full article

Somatic embryogenesis (SE) cloning techniques for Nordmann fir Christmas tree production have been pursued and refined in Denmark, and three SE clonal trials with 201 SE clones from seeds of 27 Nordmann fir trees and seedlings from bulk harvest seeds in Georgia, Caucasus, were established from 2014 to 2015. This study was the first to evaluate the genetic performance of these SE clones in different sites. In addition, the performance of SE clones and (zygotic) normal seedlings in the field was compared in this study. This study was based on three key groups of traits for Christmas tree production, measured 5 and 6 years after planting: growth, commercial tree quality, and disorder. Seedlings grew faster and had better Christmas tree quality than SE clones. There were significant family effects for all traits, indicating that a good family also produced good clones on average. Growth and disorder traits were under moderate genetic control, with estimated broad-sense heritability (H²) from 0.19 to 0.31 and from 0.20 to 0.28, respectively. Quality traits had low to moderate H², ranging from 0.09 to 0.24. Significant genotype-by-environment interactions were shown for Christmas tree quality, post-harvest needle retention, and branch angle, suggesting the importance of choosing the right clone at each site. There was no significant interaction in height among the years. Superior clones, compared to the unbred seed source, were identified by combining several important traits. Overall, the somatic clones were well established but had slower growth compared to standard seedlings. Full article

Urban parks are essential for offsetting high carbon emissions in cities, which are known to be high emitters. This study quantified carbon uptake and storage in Daejeon and Daegu, two major metropolitan cities in South Korea, and explored planting strategies to promote carbon offset services. Mean carbon uptake and storage per unit area in the study parks were 2.6 ± 0.1 t/ha/yr and 29.9 ± 1.7 t/ha, respectively. The urban park trees of a metropolitan city in South Korea were estimated to annually sequester and store 50 kt/yr and 572 kt of carbon, respectively. This carbon uptake equaled 1.5% of the total annual carbon emissions from residential energy consumption. The economic value of the carbon uptake was equivalent to $3.3 million/yr, which is 1.50% of the annual establishment budget of urban forests of the Korea Forest Service. Planting strategies included reducing unnecessary grass and pavement areas, the active planting of trees in the potential planting space, multilayered planting, and planting tree species with high growth rates. These results are expected to guide policies related to carbon credits, which have recently emerged as major concerns, and to provide useful information for quantifying carbon offset services in greenspace establishment projects. Full article

The comprehensive indexes approach based on stand structure parameters is mainly used to select trees for harvest. However, these indexes do not consider the comprehensive impact of horizontal and vertical structures, leading to an incomplete analysis of the forest structure and an inaccurate selection of trees for harvest. To solve this problem, we constructed a comprehensive decision index of logging (CDIL), integrating horizontal and vertical structure parameters which can identify harvest trees more scientifically. In this study, we took the Shanxia Forest Farm in the Jiangxi Province of China as the experimental area and used mixed broadleaf/conifer forests at different ages as our experimental sample. We selected eight horizontal and vertical spatial structure parameters to establish an efficient, objective, and accurate comprehensive decision index of logging. We combined 3D visualization technology to realize the dynamic visualization simulation of the index at different intensities of tending and felling management. The results indicated that the proposed CDIL-index could effectively optimize the forest spatial structure. From the perspective of stand structure adjustment, the optimal thinning intensity was 20%. The average CDIL in each plot decreased by more than 80% after logging, while the change range of each plot was between 30% and 70% after the F index was applied to implement tending and logging. The CDIL was 11.4% more accurate in selecting trees for harvesting than the F index. In this study, the main conclusion is that the CDIL would enable forest managers to more accurately choose trees for harvesting, leading to forest adjustment that would reduce the competition pressure among trees and improve the distribution and health of trees, possibly making the forest structure more stable. Full article

In cultural heritage conservation science, moisture content (MC) is an essential factor to determine. At the same time, it is essential to choose non-destructive and non-invasive approaches for more sustainable investigations and make them safe for the environment and the sample. The question addressed in this work concerns the possibility and the opportunity to investigate waterlogged wood by using nuclear magnetic resonance imaging (MRI) clinical scanners to carry out non-destructive volumetric diagnostics. In this study, MRI, the most important non-invasive medical imaging technique for human tissue analysis, was applied to study archaeological waterlogged wood samples. This type of archaeological material has a very high moisture content (400%–800%), thus, it is an ideal investigative subject for MRI which detects water molecules inside matter. By following this methodology, it was possible to obtain information about water content and conservation status through a T₁, T₂, and T₂* weighted image analysis, without any sampling or handling, and the samples were directly scanned in the water where they were stored. Furthermore, it permited processing 3D reconstruction, which could be an innovative tool for the digitalization of marine archaeological collections. In this work, 16 modern species of wood and a waterlogged archaeological wood sample were studied and investigated using a clinical NMR scanner operating at 3T. The results were compared with X-ray computed tomography (CT) images, as they had already been used for dendrochronology. The comparison highlights the similar, different, and complementary information about moisture content and conservation status in an all-in-one methodology obtainable from both MRI and CT techniques. Full article

Forest infrastructure is an important material basis for healthy forests. According to public goods theory, most forest infrastructures are quasi-public goods, with demand exceeding supply, more than one supplier, unclear responsibilities between suppliers, and a resultant free-rider problem. This study explored ways to improve the supply of goods for forest infrastructure when the government—as leader—cooperates with foresters—as followers. Experimental economics were used to explain the factors that influence the behaviour of forest infrastructure quasi-public goods suppliers; to design twelve policy scenarios by communication, information feedback, rewards and punishments, and leadership styles; and to simulate the changes in foresters’ supply behaviour in different scenarios to analyse which policies were conducive to improving the supply of quasi-public forest infrastructures. The results were as follows: communication, rewards and punishments, information feedback, and leadership style reduce foresters’ free-riding behaviour; communication, rewards, and punishment increase supply, and, furthermore, the supply of the scenario with rewards and punishment is 1.792–4.616 times that of the situation without rewards and punishment; without the constraints of rewards and punishment, only feedback information reduces the supply; and the p values of the Mann–Whitney U test for the influence of leadership style on the supply level of forest infrastructure were all greater than 0.05, which indicates that no significant difference exists between leading by words and leading by example in supply improvement. When foresters are able to communicate with each other, reward and punishment exist, and information feedback is provided; hence, the supply of foresters is higher regardless of whether the government leads by words or by example. This study provided policy suggestions on how to improve the supply of quasi-public goods for forestry infrastructure, namely, that the organizer should organize foresters to fully negotiate before raising funds for infrastructure construction; publish, when appropriate, the supply and income of foresters; and formulate appropriate reward and punishment measures. Full article

As a result of the progressing climate changes, there is an increase in the volume of pine deadwood harvested each year from Polish forests. Its presence is an important part of the forest ecosystem; however, there are some indications that the material obtained from dying trees can be characterized by lower quality and properties. Taking into account the growing issue of tree dieback, the volume of pine wood annually harvested in Poland, and the importance of wooden products from an economic standpoint, preliminary research aimed at recognizing the process and its effect on the mechanical properties was conducted. Model trees in Brzeg Forest District were selected based on the crown defoliation. The properties of wood obtained from trees representing three different categories of soundness were determined according to the relevant standards. Based on the results of density, modulus of elasticity, bending strength, and compressive strength, it was found that there were statistically significant differences in wood quality depending on the condition of the tree. The results were particularly interesting in the case of compressing strength, where a healthy tree of lower density showed a similar strength to a dying tree with a much higher density. Full article