Journal of Forestry Research最新文献

Temperate woodland vegetation is initially determined by spatiotemporal and historical factors, mediated by complex biotic interactions. However, catastrophic events such as disease outbreaks (e.g., sweet chestnut blight, ash dieback), infestations of insect pests, and human-accelerated climate change can create canopy gaps due to systematic decline in, or loss of, tree species that was once an important part of the canopy. Resultant cascade effects have the potential to alter the composition of woodland ecosystems quickly and radically, but inherent lag times make primary research into these effects challenging. Here, we explore change in woodland vegetation at 10 sites in response to canopy opening using the Elm Decline, a rapid loss of Ulmus in woodlands across northwestern Europe ~ 5800 years ago that coexisted alongside other stressors such as increasing human activity, as a palaeoecological analogue. For arboreal taxa, community evenness significantly decreased, within-site turnover significantly increased, and richness remained unchanged. Changes in arboreal taxa were highly site-specific but there was a substantial decline in woody climbing taxa, especially Hedera (ivy), across the majority of sites. For shrub taxa, richness significantly increased but evenness and turnover remained consistent. Interestingly, however, there was a significant increase in abundance of shrubs at 70% of sites, including Calluna (heather), Ilex (holly) and Corylus (hazel), suggesting structural change. Surprisingly, there was no change in richness, evenness or turnover for herb taxa, possibly because change was highly variable spatially. However, there was a marked uptick in the disturbance indicator Plantago (plantain). Overall, these findings suggest that woodlands with sustained reduction in, or loss of, a tree species that once formed an important part of the canopy has profound, but often spatially idiosyncratic, impacts on vegetation diversity (richness), composition (evenness), stability (turnover), and on abundance of specific taxa, especially within the shrub layer. Use of this palaeoecological analogue, which was itself complicated by cooccurring changes in human activity, provides a valuable empirical insight into possible cascade effects of similar change in canopy opening in contemporary settings, including Ash Dieback.

Botryosphaeria laricina (larch shoot blight) was first identified in 1973 in Jilin Province, China. The disease spread rapidly and caused considerable damage because its pathogenesis was unknown at the time and there were no effective controls or quarantine methods. At present, it shows a spreading trend, but most research can only conduct physiological analyses within a relatively short period, combining individual influencing factors. Nevertheless, methods such as neural network models, ensemble learning algorithms, and Markov models are used in pest and disease prediction and forecasting. However, there may be fitting issues or inherent limitations associated with these methods. This study obtained B. laricina data at the county level from 2003 to 2021. The dataset was augmented using the SMOTE algorithm, and then algorithms such as XGBoost were used to select the significant features from a combined set of 12 features. A new stacking fusion model has been proposed to predict the status of B. laricina. The model is based on random forest, gradient boosted decision tree, CatBoost and logistic regression algorithms. The accuracy, recall, specificity, precision, F₁ value and AUC of the model reached 90.9%, 91.6%, 90.4%, 88.8%, 90.2% and 96.2%. The results provide evidence of the strong performance and stability of the model. B. laricina is mainly found in the northeast and this study indicates that it is spreading northwest. Reasonable means should be used promptly to prevent further damage and spread.

Small heat shock proteins (sHSPs) act as molecular chaperones that can prevent the accumulation of damaged proteins during abiotic stress, especially heat shock, but the mechanism is not clear. To study the function of sHSPs in Lenzites gibbosa, a common polypore in northern temperate forests that causes spongy white rot of broadleaf trees, under temperature stress, L. gibbosa mycelia were grown at 25 °C for 9 d, treated at 33 °C for 15, 30, 60, and 120 min before sequencing the transcriptomes. From among 32 heat shock protein (HSP) genes found in the screen of the transcriptome data, a highly expressed gene was cloned and named Lghsp17.4. RT-qPCR was used to analyze the expression of the gene Lghsp17.4 under heat shock and dye stress. Both treatments induced higher expression of Lghsp17.4 at the transcriptional level, indicating that Lghsp17.4 might function in the response to heat stress and dye degradation. We previously found that L. gibbosa generally had a heat shock reaction (HSR) during degradation of aromatic compounds, and HSPs were always produced with manganese peroxidases (MnPs) and other lignin-degrading enzymes. Therefore, we measured the activity of MnPs in L. gibbosa after 33 °C heat shock to analyze the relationship between MnPs expression and Lghsp17.4 expression. Heat shocks of 0–30 min increased MnPs activity, and the change in MnPs activity were closely positively correlated with the expression levels of Lghsp17.4 over time, indicating a potential connection and interaction between LgHSP17.4 and MnPs during the HSR in L. gibbosa. Thus, LgHSP17.4 might have a positive regulatory effect on the HSR in L. gibbosa and be a critical component of a stress resistance mechanism.

The survival strategy of plants is to adjust their functional traits to adapt to the environment. However, these traits and survival strategies of evergreen broad-leaved forest species are not well understood. This study examined 10 leaf functional traits (LFTs) of 70 common plant species in an evergreen broad-leaved forest in Huangshan Mountain to decipher their adaptive strategies. The phylogenetic signals of these LFTs were assessed and phylogenetically independent contrasts (PIC) and correlation analyses were carried out. LFTs were analyzed to determine their CSR (C: competitor, S: stress-tolerator, R: ruderal) strategies. The results show that plant species exhibit different leaf functional traits and ecological strategies (nine strategies were identified; the most abundant were S/CS and S/CSR strategies). Some traits showed significant phylogenetic signals, indicating the effect of phylogeny on LFTs to an extent. Trait variations among species suggest distinct adaptation strategies to environmental changes. The study species were mainly clustered on the C-S strategy axis, with a high S component. Species leaning toward the C-strategy end (e.g., deciduous species), favored a resource acquisition strategy characterized by higher specific leaf area (SLA), greater nutrient contents (N and P), lower leaf dry matter content (LDMC), and reduced nutrient utilization efficiency (C: N and C: P). Conversely, species closer to the S-strategy end (e.g., evergreen species) usually adopted a resource conservative strategy with trait combinations contrary to those of C-strategy species. Overall, this study corroborated the applicability of the CSR strategy at a local scale and provides insights into the varied trait combinations and ecological strategies employed by plant species to adapt to their environment. These findings contribute to a better understanding of the mechanisms involved in biodiversity maintenance.

Although numerous studies have proposed explanations for the specific and relative effects of stand structure, plant diversity, and environmental conditions on carbon (C) storage in forest ecosystems, understanding how these factors collectively affect C storage in different community layers (trees, shrubs, and herbs) and forest types (mixed, broad-leaved (E), broad-leaved (M), and coniferous forest) continues to pose challenges. To address this, we used structural equation models to quantify the influence of biotic factors (mean DBH, mean height, maximum height, stem density, and basal area) and abiotic factors (elevation and canopy openness), as well as metrics of species diversity (Shannon–Wiener index, Simpson index, and Pielou’s evenness) in various forest types. Our analysis revealed the critical roles of forest types and elevation in explaining a substantial portion of variability in C storage in the overstory layer, with a moderate influence of stand factors (mean DBH and basal area) and a slightly negative impact of tree species diversity (Shannon–Wiener index). Notably, forest height emerged as the primary predictor of C storage in the herb layer. Regression relationships further highlighted the significant contribution of tree species diversity to mean height, understory C storage, and branch biomass within the forest ecosystem. Our insights into tree species diversity, derived from structural equation modeling of C storage in the overstory, suggest that the effects of tree species diversity may be influenced by stem biomass in statistical reasoning within temperate forests. Further research should also integrate tree species diversity with tree components biomass, forest mean height, understory C, and canopy openness to understand complex relationships and maintain healthy and sustainable ecosystems in the face of global climate challenges.

Based on the survey data of nine primitive broad-leaved Korean pine forest plots ranging from 1 to 10.4 ha in Heilongjiang Province, this study used the moving window method and GIS technology to analyze the variation characteristics of the spatial distribution pattern of forest biomass in each plot. We explored the minimum area that can reflect the structural and functional characteristics of the primitive broad-leaved Korean pine forest, and used computer simulation random sampling method to verify the accuracy of the minimum area. The results showed that: (1) Through the analysis of the spatial distribution raster map of biomass deviation in the plots at various scales of 10 − 100 m, there is a minimum area (0.64 ha) for the critical range of biomass density variation in the primitive broad-leaved Korean pine forest. This minimum area based on biomass density can indirectly reflect the comprehensive characteristics of productivity level per unit area, structure, function, and environmental quality of the primitive broad-leaved Korean pine forest community. (2) Using computer simulation random sampling, it was found that only by sampling in a specific plot larger than or equal to the minimum area can equivalent or similar results be achieved as random sampling within the plot, indicating that the minimum area determined by the moving window method is accurate. (3) The minimum area determined in this paper is an excellent indicator reflecting the complexity of community structure, which can be used for comparing changes in community structure and function before and after external disturbances, and has a good evaluation effect. This minimum area can also be used as a basis for scientific and reasonable setting of plot size in the investigation and monitoring work of broad-leaved Korean pine forests in this region, thereby achieving the goals of improving work efficiency and saving work costs.

Forest hydrology, the study of water dynamics within forested catchments, is crucial for understanding the intricate relationship between forest cover and water balances across different scales, from ecosystems to landscapes, or from catchment watersheds. The intensified global changes in climate, land use and cover, and pollution that occurred over the past century have brought about adverse impacts on forests and their services in water regulation, signifying the importance of forest hydrological research as a re-emerging topic of scientific interest. This article reviews the literature on recent advances in forest hydrological research, intending to identify leading countries, institutions, and researchers actively engaged in this field, as well as highlighting research hotspots for future exploration. Through a systematic analysis using VOSviewer, drawing from 17,006 articles retrieved from the Web of Science Core Collection spanning 2000–2022, we employed scientometric methods to assess research productivity, identify emerging topics, and analyze academic development. The findings reveal a consistent growth in forest hydrological research over the past two decades, with the United States, Charles T. Driscoll, and the Chinese Academy of Sciences emerging as the most productive country, author, and institution, respectively. The Journal of Hydrology emerges as the most co-cited journal. Analysis of keyword co-occurrence and co-cited references highlights key research areas, including climate change, management strategies, runoff-erosion dynamics, vegetation cover changes, paired catchment experiments, water quality, aquatic biodiversity, forest fire dynamics and hydrological modeling. Based on these findings, our study advocates for an integrated approach to future research, emphasizing the collection of data from diverse sources, utilization of varied methodologies, and collaboration across disciplines and institutions. This holistic strategy is essential for developing sustainable approaches to forested watershed planning and management. Ultimately, our study provides valuable insights for researchers, practitioners, and policymakers, guiding future research directions towards forest hydrological research and applications.

Understanding why elements are distributed in tree xylem in a particular way is a significant challenge in dendrochemistry. This study explored a hypothesis that metal elements in the xylem interact due to differences in physical properties such as ionic radius and ionization potential. Scots pine in an even-aged stand established during the early 1970s in eastern Siberia was the study species. Increment cores were taken from the north and south sides of trees and scanned with an X-ray fluorescent multi scanner. With the help of X-ray scanning, the following elements were analyzed: aluminum (Al), potassium (K), calcium (Ca), titanium (Ti), manganese (Mn), iron (Fe), copper (Cu), strontium (Sr) and zinc (Zn). Scanning data on the elements were split into early-wood and late-wood data for each year of growth. The following ratios were analyzed: Ca/Sr, Fe/Ca, Fe/Sr, Al/Cu, Al/Zn, Ti/Mn, and Mn/K. Among these, ones having a consistent pattern across tree rings, the ratios show a more or less dependable relationship: that an element shows a larger decrease (relative another element) that has a larger ionic radius and lower ionization potential. Hypothetically, this may be due to the advantage of an ion with smaller ionic radius and higher ionization potential under a deficit of accommodation centers in organic molecules. An experiment approach should be applied to clarify the relationships.

Acorn production in oaks (Quercus spp.) shows considerable inter-annual variation, known as masting. The effects of pollen sourced from trees within or outside the stand on acorn production were investigated in pedunculate oak (Quercus robur L.) in an ancient mixed woodland during two moderate masting years. Comparisons were made between natural pollination, hand pollinations with out-of-stand pollen, in-stand pollen or a 1:1 combination of the two pollen sources, and for bagged flowers left unpollinated. After all treatments, > 85% of the flowers or developing acorns were aborted between May and August of both years. When flowers were protected with pollen bags and no pollen added, no acorns were produced. In contrast, hand pollination with out-of-stand pollen produced the most acorns both years and significantly more than within-stand pollen or natural pollination in 2022. Hand pollination with out-of-stand or within-stand pollen provided significantly more acorns than natural pollination in 2023. In 2022, hand pollination with a 1:1 mixture of out-of-stand and within-stand pollen yielded an intermediate number of mature acorns between those for the out-of-stand and within-stand pollination treatments. The study provides clear evidence of maternal choice during acorn development in pedunculate oak and of the benefits of pollen supplementation. It also confirms that pedunculate oak is a fruit-maturation masting species; abortion of pollinated flowers and immature acorns determines a mast year (rather than the number of flowers produced) at this site.

The most important process before leaf senescence is nutrient resorption, which reduces nutrient loss and maximizes plant fitness during the subsequent growth period. However, plants must retain certain levels of nitrogen (N) in their leaves to maintain carbon assimilation during hardening. The objective of this study was to investigate the tradeoffs in N investment between leaf N resorption and N for photosynthesis in seedlings with increased soil fertility during the hardening period. A field experiment was conducted to determine if and how soil fertility treatments (17, 34, or 68 mg N seedling⁻¹) affected N resorption and allocation to the photosynthetic apparatus in Quercus mongolica leaves during the hardening period. Seedlings were sampled at T₁ (after terminal bud formation), T₂ (between terminal bud formation and end of the growing period), and T₃ (at the end of the growing period). Results showed that photosynthetic N content continued to rise in T₂, while N resorption started from non-photosynthetic N. Leaf N allocation to the photosynthetic apparatus increased as soil fertility increased, delaying N resorption. Additionally, soil fertility significantly affected N partitioning among different photosynthetic components, maintaining or increasing photosynthetic traits during senescence. This study demonstrates a tradeoff in N investment between resorption and photosynthesis to maintain photosynthetic assimilation capacity during the hardening period, and that soil fertility impacts this balance. Q. mongolica leaves primarily resorbed N from the non-photosynthetic apparatus and invested it in the photosynthetic apparatus, whereas different photosynthetic N component allocations effectively improved this pattern.