European Journal of Forest Research最新文献

Road construction constitutes a significant disruption to natural ecosystems. Globally, high-elevation regions are among the most fragile and sensitive ecosystems, while systematic information regarding the impact of road construction on soil properties and plant communities in these regions remains scarce. To fill this gap, this study employed a paired plot design, establishing the natural and disturbed plots along the National Highway 214 (48 years) and 219 (12 years) from Yunnan Province to Tibet Autonomous Region in Southwest China, with elevation ranging from 2,400 m to 4,900 m. A total of 68 sampling plots (34 locations) were selected to compare the pattern of soil properties and plant communities between the two categories along elevation gradient. Results revealed the restoration of soil properties post-disturbance had been multifaceted and long-lasting. Specifically, disturbed plots exhibited a significant increase in soil pH, while soil moisture, TC, TN, TP, NH₄-N, and AK suffered substantial loss. Moreover, the strong recovery ability of shrub and herbaceous species was observed in our study, while tree communities were difficult to revert to their original state. Furthermore, the influence of elevation on vegetation restoration also varied depending on plant life forms. In light of these findings, appropriate strategies including restorative planting, soil amelioration, customized restoration plan for specific ecosystems, monitoring and adaptive management, were proposed to mitigate the negative impacts and promote the ecosystem recovery after road construction in these ecologically fragile regions.

Autotrophic microorganisms play a significant role in atmospheric CO₂ fixation and soil organic carbon (SOC) sequestration in diverse ecosystems, but little is known about their role in karst forests. To investigate the composition and changes of autotrophic microbial communities during degraded karst forest restoration, the related functional genes and microorganisms from three restoration stages (shrubbery, TG; secondary forest, SG; old-growth forest, OG) were examined through metagenomic sequencing. Their underlying drivers and contributions to SOC were investigated using structural equation modeling (SEM) and regression analysis. Karst forest restoration resulted in the synchronous recovery of above-ground plants and soil conditions. When TG was restored to OG, soil autotrophic CO₂ fixation microbes changed significantly, indicated by an increase in microbial functional strength and diversity. Among the six examined functional pathways, the rTCA cycle contributed the most (0.074–0.082%), while the WL pathway contributed the least (0.008–0.010%) to CO₂ fixation functions. Except the Calvin cycle, genes involved in the other five pathways showed an increase with karst forest restoration. SEMs further revealed that soil pH and available nitrogen directly drive the increase in microbial autotrophic CO₂ fixation functions. In karst forests, autotrophic CO₂-fixing microorganisms play a crucial role in enhancing SOC, particularly through the DC/4-HB cycle, 3-HP/4-HB cycle, and WL pathway. Soil microbial communities involved in autotrophic CO₂ fixation were predominantly attributed to Proteobacteria (43.02–32.42%) and Actinobacteria (18.83–30.89%), although their contributions varied across different stages. These results highlight the significant contribution of autotrophic microorganisms to the SOC of karst forests and enhance our understanding of the microbial mechanisms behind soil C sequestration.

This study focuses on the effect of differences in acorn dropping time on seedling establishment in two abundant Mediterranean oak species: Quercus ilex subsp. ballota and Q. suber. These species show extended seed dropping seasons (i.e., 4 to 5 months) and the fallen acorns thus experience variable conditions, including differences in climate and microclimate, as well as differences in biological interactions (mainly pre- and post-dispersal predation by insect larvae and rodents, respectively). We conducted two field experiments and a field survey on acorn infection by insect larvae and analysed the ability of early and late dropped acorns to achieve success (i.e., remaining healthy, germinating, and emerging as seedlings). The results indicated that pre- and post-dispersal predation of propagules changed over time. However, these factors had low effect on final seedling success. In opposition, warmer (i.e., autumn) conditions at acorn dropping and sowing time decreased seedling establishment in Q. suber, likely by a lack of cold stratification, while the conditions had no effect on Q. ilex subsp. ballota seedlings. We conclude that climate warming can selectively decrease the number of seedlings that are established in late springtime, before the onset of the characteristic Mediterranean summertime drought, thus negatively affecting the population dynamic in these species, which exhibit a high level of physiological dormancy as they depend on cold conditions to maximise acorn germination and epicotyl emergence.

The complex interplay between primary and secondary growth processes in trees holds paramount significance in unraveling the physiological connections within distinct tree tissues. In this study, we continuously monitored the intra-annual radial growth of Pinus koraiensis, Quercus mongolica, and Betula platyphylla in Changbai Mountain of northeast China using microcore techniques from April to September 2021. Additionally, we used existing leaf phenology models to simulate the seasonal variations of leaf area of three species. Our results revealed substantial difference in radial growth dynamics and leaf expansion patterns among the different wood species. Notably, a synchronization between leaf expansion and radial growth was observed in certain phases for pine and birch, with a significant positive correlation between the rates of leaf expansion and radial growth. Conversely, oak exhibited no synchrony between leaf development and radial growth. Temporal disparities between cambial phenology and leaf phenology were observed. Specifically, for pine, leaf unfolding occurred prior to the onset of wall-thickening, while leaf shedding took place after the cessation of lignification. Oak exhibited a delayed leaf unfolding compared to the initiation of secondary wall formation, and leaf shedding notably occurred later than the cessation of radial growth. In contrast, birch displayed an earlier leaf unfolding in comparison to the onset of radial growth, and the cessation of lignification was later than leaf shedding. These findings indicate the diversity in physiological mechanisms and survival strategies among different wood species. Our results suggest that radial growth in pine and birch appears to be heavily reliant on photosynthetic activity of leaves, while oak places greater emphasis on carbon storage, particularly during early growing season. The findings provide new insights into the complex mechanisms of tree growth and are critical for predicting future species suitability in temperate forests.

Height to crown base (HCB) is an important tree-level characteristic used to determine crown size and serves as an important input variable for forest growth and yield models. Competition between forest stands and environmental conditions are the main factors influencing HCB not only through independent effects but also through interactive effects. In addition, it is unclear whether these effects on HCB differ depending on the social status of the tree. Accordingly, we conducted a pioneering study to assess the independent and interactive effects of competition, climate, and soil on HCB using measurements from a total of 7188 Korean pine (Pinus koraiensis) trees at 98 sample plots located in northeastern China. Moreover, HCB simulations under different competitive conditions or soil gradients were provided based on the actual local climatic types to provide targeted recommendations for plantations. The results showed that stand basal area (BA), the basal area of trees larger than the subject tree (BAL), mean temperature of the coldest month (MCMT), Hargreaves climatic moisture deficit (CMD), and total nitrogen (TN) were the main factors influencing HCB. As CMD increases, the influence direction of BA and MCMT on HCB changes, and the intensity of their influence decreases. The results of hierarchical partitioning analysis showed that the impacts of climate on HCB were different depending on social status. Suppressed trees exhibit a lower climate sensitivity compared to dominant and intermediate trees. Simulation results indicate that regulating stand competition through thinning operations and adjusting soil nitrogen content by increasing understory vegetation promote crown recession, thereby increases HCB. Our findings highlight the significance of independent and interactive considering competition, climate, and soil variables to improve HCB model predictions at large spatial scales and guidance on stand management in the context of climate change.

Information on terrain conditions is a prerequisite for planning environmentally and economically sustainable forest harvesting operations that avoid negative impact on soils. Current soil data are coarse, and collecting such data with traditional methods is expensive. Forest harvesters can be harnessed to estimate the rolling resistance coefficient ((mu _{RR})), which is a proxy for forest trafficability. Using spatio-temporal data on engine power used, speed travelled, and machine inclination, (mu _{RR}) can be computed for harvest areas. This study describes an extensive, high-resolution data on (mu _{RR}) collected in a boreal forest landscape in Southern Finland during the non-frost period of 2021, covering roughly 50 km of harvester routes. We report improvements in removing some of the previous restrictions on calculating (mu _{RR}) on steeper slopes, enabling the calculation within a (-10^{circ }) to (+10^{circ }) slope range with a speed range of 0.6–1.2 ms(^{-1}). We characterise the variation in (mu _{RR}) both between and within 11 test sites harvested during the April-August period. The site mean (mu _{RR}) varies from (sim) 0.14 to 0.19 and shows significant differences between the sites. Using simulations of the hydrological state of the soil and open spatial data on forest and topography, we identify features that best explain the extremes of (mu _{RR}) within the sites. Several wetness-related indices, such as the depth-to-water index with varying thresholds, explain the (mu _{RR}) extremes, while biomass-related stand attributes indirectly explain these through their linkage to site and soil characteristics. Obtaining (mu _{RR}) from actual operational data extends the capabilities of large-scale harvester-based data collection and paves the way for building data-driven models for trafficability prediction.

The use of intensive silviculture to increase forest productivity in commercial plantations will undoubtedly persist into the future. This review synthesizes and analyses studies that have investigated the influence of fertilization on density, microfibril angle (MFA), and modulus of elasticity (MOE) of different Pinus species under intensive management. It was found that in general, ring width or growth rate demonstrated a negative correlation with density, and a positive relationship with MFA. Also, the relationship between growth rate and density and MFA were age specific and often non-significant at the whole stem level. Earlywood and latewood were influenced differently by fertilization: Earlywood width and density increased while in latewood, width stayed constant but density decreased. This resulted in a decrease in within-ring heterogeneity of density and density-related properties. Since latewood generally contributed more to whole-ring density, the net effect was that whole-ring wood density of pines mostly decreased with fertilization. Given that fertilization often resulted in a decrease in wood density and an increase in MFA, MOE decreased with fertilization. Most fertilization-wood-property studies on Pinus involved nitrogen and phosphorus fertilizers with differing quantity and ratios. Results suggest that nitrogen may cause the greatest change in wood growth and properties. An important question that was often unanswered in research, was whether the effect of specific fertilization treatments on wood properties were purely based on the influence of increased growth or whether there were direct influences not explained by growth. Also, despite potassium being an important elemental component of many fertilizers, relatively little work has been done to determine its effect on wood properties.

Swing yarders in running skyline configuration using either grapples or chokers represent the most common configuration for cable yarding in coastal British Columbia. In this context, whole-tree logging and short work cycles lead to heavy and repeated loads applied to the trees and stumps when used as anchors for the rigging cables. Moreover, increased harvesting of second-growth forest stands leads to the unavailability of large and safe trees, thus introducing new challenges to identify suitable anchors and potentially increases safety risks of cable yarding operations.

The present study aimed to collect evidence of the mechanical response provided by anchors for typical cable yarders used in second-growth harvesting in coastal British Columbia, and test the suitability of innovative techniques for the stability assessment based on the relationship between the anchor root-plate rotations and the related applied tensile forces. A conspicuous dataset could be derived from all the surveys, storing anchor rotations from a total of 1522 work cycles of which 1224 work cycles included also tensions measurements. The methodological approach was proven effective for monitoring different rigging configurations giving proof that repeated loading affects the stability of a tree/stump which can rapidly change over few hours of active yarding operations. Acquired data proved also that comparing theoretical failure limits with anchor rotations could be a valid approach however a considerable amount of species-specific data from tree pulling tests is required.

The phenotype of a woody plant represents its unique morphological properties. Population discrimination and individual classification are crucial for breeding populations and conserving genetic diversity. Machine Learning (ML) algorithms are gaining traction as powerful tools for predicting phenotypes. The present study is focused on classifying and clustering the seeds and seedlings in terms of morphological characteristics using ML algorithms. In addition, the k-means algorithm is used to determine the ideal number of clusters. The results obtained from the k-means algorithm were then compared with reality. The best classification performance achieved by the Random Forest algorithm was an accuracy of 0.648 and an F1-Score of 0.658 for the seed traits. Also, the best classification performance for stone pine seedlings was observed for the k-Nearest Neighbors algorithm (k = 18), for which the accuracy and F1-Score were 0.571 and 0.582, respectively. The best clustering performance was achieved with k = 2 for the seed (average Silhouette index = 0.48) and seedling (average Silhouette Index = 0.51) traits. According to the principal component analysis, two dimensions accounted for 97% and 63% of the traits of seeds and seedlings, respectively. The most important features between the seed and seedling traits were cone weight and bud set, respectively. This study will provide a foundation and motivation for future efforts in forest management practices, particularly regarding reforestation, yield optimization, and breeding programs.

The aging process is influenced by the accumulation of both beneficial and harmful factors in the external environment. While extensive literature has explored the health benefits of short-term forest bathing, the potential for long-term exposure to forests to delay the aging process remains unclear. This study aimed to investigate the impact of prolonged urban forest contact on aging using a murine model. Forty male Specified Pathogen Free degree Kunming mice (6 weeks old, average weight 30.44 ± 0.91 g) were subjected to continuous subcutaneous injection of D-galactose in an urban environment and an urban forest environment to simulate an accelerated aging process lasting six weeks. Results showed that compared to urban environment, mice living in the forest environment exhibited significantly increased levels of serum oxidases CAT, GSH-Px, and SOD, as well as decreased levels of oxidative products H₂O₂ and MDA. These findings suggest that long-term forest living enhances serum Nrf2 expression, downstream oxidase activity, total antioxidant capacity, and resistance to free radicals and oxidative products, thus delaying the aging process. This study offers valuable insights into the potential health benefits of long-term forest living, which may play a role in delaying the aging process in humans.