Evergreen Broad-leaved Forest Research Articles

The complete mitochondrial genome of Castanopsis carlesii and Castanea henryi reveals the rearrangement and size differences of mitochondrial DNA molecules

BackgroundCastanopsis carlesii is a dominant tree species in subtropical evergreen broad-leaved forests and holds significant ecological value. It serves as an excellent timber tree species and raw material for cultivating edible fungi. Henry Chinquapin (Castanea henryi) wood is known for its hardness and resistance to water and moisture, making it an exceptional timber species. Additionally, its fruit has a sweet and fruity taste, making it a valuable food source. However, the mitogenomes of these species have not been previously reported. To gain a better understanding of them, this study successfully assembled high-quality mitogenomes of C. carlesii and Ca. henryi for the first time.ResultsOur research reveals that the mitochondrial DNA (mtDNA) of C. carlesii exhibits a unique multi-branched conformation, while Ca. henryi primarily exists in the form of two independent molecules that can be further divided into three independent molecules through one pair of long repetitive sequences. The size of the mitogenomes of C. carlesii and Ca. henryi are 592,702 bp and 379,929 bp respectively, which are currently the largest and smallest Fagaceae mitogenomes recorded thus far. The primary factor influencing mitogenome size is dispersed repeats. Comparison with published mitogenomes from closely related species highlights differences in size, gene loss patterns, codon usage preferences, repetitive sequences, as well as mitochondrial plastid DNA segments (MTPTs).ConclusionsOur study enhances the understanding of mitogenome structure and evolution in Fagaceae, laying a crucial foundation for future research on cell respiration, disease resistance, and other traits in this family.

Progress in Research on Terpenoid Biosynthesis and Terpene Synthases of Lauraceae Species

Lauraceae, an important family of Angiospermae, comprises over 2500 species widely distributed in tropical and subtropical evergreen broad-leaved forests. This family is renowned for its rich resource of terpenoids, particularly monoterpenes, sesquiterpenes, and diterpenes. These compounds not only impart specific scents to Lauraceae species but also play crucial roles in plant growth, development, and environmental adaptation. These compounds also possess extensive bioactivities, such as antioxidant, antibacterial, anti-inflammatory, and neuroprotective effects, making them valuable in the fields of perfumery, cosmetics, food, and medicine, and thus holding significant economic value. Recent advancements in high-throughput technologies, especially genomics, transcriptomics, and metabolomics, have significantly advanced our knowledge of the chemical constituents and biosynthetic pathways of terpenoids in Lauraceae species. Such progress has also shed light on the diversity and functionality of the terpene synthases (TPSs) gene family, a key enzyme involved in terpenoid biosynthesis. This paper reviews the latest research findings on the biosynthetic pathways of terpenoids and their key enzyme-encoding gene families in Lauraceae plants. We also analyze the evolutionary patterns of TPS gene family members of four Lauraceae species at the whole-genome level and summarize their mechanisms of action in secondary metabolite synthesis. Furthermore, this paper highlights the current research challenges and proposes prospects, such as the complexity of gene families, the uncertainties in functional predictions, and unclear regulatory mechanisms. Our objective is to provide scientific foundations for the in-depth analysis of terpenoid biosynthesis mechanisms and the development and utilization of natural products in Lauraceae plants.

A New Fossil Genus of Altingiaceae Based on Unlobed Leaves from Eocene Subtropical Evergreen Broadleaved Forest in Europe

A New Fossil Genus of Altingiaceae Based on Unlobed Leaves from Eocene Subtropical Evergreen Broadleaved Forest in Europe

Arsenic and cadmium in the hydrological cycle and soil in a maquis broadleaved evergreen forest stand in Greece. Sources of some uncertainties

ABSTRACT The concentrations and fluxes of arsenic (As) and cadmium (Cd) were examined in the hydrological cycle, litterfall and soils in a maquis broadleaved evergreen forest stand in western Greece. The concentrations of the metals in the hydrological cycle ranged from 0.076 to 0.306 μg L−1 and 0.040–0.050 μg L−1 for As and Cd, respectively. It was found that the enrichment of As in the atmosphere was both due to suspended geogenic material and long range transfer, whereas for Cd the long range transfer was the predominant way for deposition. Two models were assessed to find the volumes of percolation water to compare the fluxes with the estimated ones derived from soil solution measurements. The daily deterministic forest-hydrological model (WBS3) was found to perform better than the physically based 1D semi-distributed soil-plant-atmosphere model (BROOK90). When calculating the total amounts of the heavy metals in soils, the statistical uncertainty derived from every soil layer has to be taken into account. The residence time of Cd in the forest floor (L + FH) of the soils was found 6.4 years, whereas that of As 36.3 years. This difference shows the mobility of Cd in comparison to As in the soils of the area.

Leaf functional traits and ecological strategies of common plant species in evergreen broad-leaved forests on Huangshan Mountain

Leaf functional traits and ecological strategies of common plant species in evergreen broad-leaved forests on Huangshan Mountain

Dendrobium namdongense (D. sect. Dendrobium), a new miniature orchid from limestone mountains of northern Vietnam

Dendrobium namdongense is described here as a new species from limestone areas of the Nam Dong Conservation Area, Thanh Hoa Province, Quan Hoa District (northern Vietnam). This species inhabits primary evergreen broad-leaved and mixed forests on karstic limestone at elevations of 900–1100 m a.s.l. in a zone of humid, cool tropical climate. A detailed illustrated description and comparison of the discovered plant with the morphologically closest species, D. fuscifaucium and D. hekouense is provided, along with data on its distribution, ecology, and phenology. The new species has a potential in ornamental horticulture. According to the criteria of the IUCN Red List, the conservation status of the species is determined as Critically Endangered (CR).

Phylogenetic relatedness and habitat affect seedling abundance of a mid-montane humid evergreen broad-leaved forest in the Gaoligong Mountains, Southwestern China

The neighborhood effect has become an important framework with which to study the mechanisms that maintain the coexistence of tree species. Phylogenetic relatedness among neighboring plants directly affects species coexistence and the maintenance of tree diversity. And some studies have reported that seedling performance is negatively correlated with phylogenetic relatedness, which termed phylogenetic negative density dependence. Soil-borne fungal pathogens affected seedling performance of phylogenetically related host species, i.e., phylogenetic Janzen–Connell effect. Seedlings may be particularly vulnerable to habitat and neighbor characteristics. Although previous studies have demonstrated the influence of neighborhood effects, phylogenetic relatedness, and habitat filtering on seedling survival, growth, and mortality, the effect of variation in these factors on seedling abundance remains unclear. To address this question, we used a 4-ha (200 m × 200 m) and monitored four-year (2020–2023) seedling dataset from a mid-montane humid evergreen broad-leaved subtropical forest in the Gaoligong Mountains, Yunnan, Southwestern China, and which consisted of 916 seedlings belonging to 56 species. The results of generalized linear mixed models showed no significant effect of conspecific adult neighbors on seedling abundance at any of the intervals evaluated. In contrast, we found evidence of phylogenetic distance density dependence in the forests of the Gaoligong Mountains. Specifically, there was a significant positive effect of the relative average phylogenetic distance between heterospecific adult neighbors and focal seedlings on focal seedling abundance in 2020; however, the relative average phylogenetic distance between heterospecific seedling neighbors and focal seedlings had a significant negative effect on seedling abundance over the four-year period (2020–2023). Among the habitat factors, only light (canopy opening) had a negative effect on seedling abundance in all four years. Light resources may be a limiting factor for seedlings, and determine seedling dynamics in subtropical forests. Overall, our results demonstrated that phylogenetic density dependence and habitat filtering affected subtropical seedling abundance. Our findings provide new evidence of the impact of phylogenetic density dependence on seedling abundance in a subtropical mid-montane humid evergreen broad-leaved forest and highlight the need to incorporate the neighborhood effect, phylogenetic relatedness, and habitat factors in models assessing seedling abundance.

Phylogeographic patterns match the floristic subdivisions: The diversification history of a widespread herb in subtropical China.

Subtropical China is dominated by evergreen broad-leaved forests (EBLFs) and is acknowledged as a critical region for its high floristic richness and endemism. Understanding of evolutionary mechanisms of such global biodiversity hotspots comes almost exclusively from long-lived tree species. Herbaceous plants represent critical biodiversity components in forests, however, the diversification history of understory herbs in subtropical EBLFs remain poorly understood. Here, we investigated the phylogeographic patterns and demographic history of Oreocharis auricula, a widespread perennial herb endemic to the EBLFs of subtropical China. Both cpDNA sequences and single-copy nuclear genes were used to investigate the genetic variation among 657 individuals from 68 populations. Evidences from molecular dating, demographic history construction, and species distribution modeling were also combined to infer the phylogeography and evolutionary history of O. auricula. Strong phylogeographic signals have been congruently observed using nuclear and plastid DNA markers, with the diversification patterns generally consistent with the recognized floristic subdivisions of subtropical China. Notably, we revealed an important phylogeographic barrier along the Nanling mountain range, which is also around a climatic transition at 24-26°N latitude in subtropical China, separating the south monsoon subtropical EBLFs from the mid-subtropical EBLFs. Demographic expansion and significant niche divergence were detected among the extant lineages, which may have diverged during the early Pleistocene. The inherent characteristics of understory herbs with limited dispersal and short generation time intensify the genetic divergence response of O. auricula to abiotic forces, contributing to the profound phylogeographic imprints of mountains and climate in such herbaceous flora. To further substantiate the generality of the identified patterns, it is paramount to extend phylogeographic investigations to other understory herbaceous taxa in subtropical China. These results have expanded our understanding of the diversification processes of subtropical forests in China.

Leaf Functional Traits and Their Influencing Factors in Six Typical Vegetation Communities.

Leaf functional traits (LFTs) have become a popular topic in ecological research in recent years. Here, we measured eight LFTs, namely leaf area (LA), specific leaf area (SLA), leaf thickness (LT), leaf dry matter content (LDMC), leaf carbon content (LCC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), and leaf potassium content (LKC), in six typical vegetation communities (sclerophyllous evergreen broad-leaved forests, temperate evergreen coniferous forests, cold-temperate evergreen coniferous forests, alpine deciduous broad-leaved shrubs, alpine meadows, and alpine scree sparse vegetation) in the Chayu River Basin, southeastern Qinghai-Tibet Plateau. Our aim was to explore their relationships with evolutionary history and environmental factors by combining the RLQ and the fourth-corner method, and the method of testing phylogenetic signal. The results showed that (i) there were significant differences in the eight LFTs among the six vegetation communities; (ii) the K values of the eight LFTs were less than 1; and (iii) except for LCC, all other LFTs were more sensitive to environmental changes. Among these traits, LA was the most affected by the environmental factors, followed by LNC. It showed that the LFTs in the study were minimally influenced by phylogenetic development but significantly by environmental changes. This study further verified the ecological adaptability of plants to changes in environmental factors and provides a scientific basis for predicting the distribution and diffusion direction of plants under global change conditions.

Decreased P Cycling Rate and Increased P-Use Efficiency after Phyllostachys edulis (Carrière) J. Houz. Expansion into Adjacent Secondary Evergreen Broadleaved Forest

Decreased P Cycling Rate and Increased P-Use Efficiency after Phyllostachys edulis (Carrière) J. Houz. Expansion into Adjacent Secondary Evergreen Broadleaved Forest

High-precision estimation of plant alpha diversity in different ecosystems based on Sentinel-2 data

At present, the accuracy of remote sensing estimation models of plant alpha diversity is generally low, and high-precision estimation models in deciduous broadleaved forest (DBF), deciduous coniferous forest (DCF) and evergreen coniferous forest (ECF) are still lacking. The main purpose of this study is to construct high-precision remote sensing models for plant alpha diversity in multiple ecosystems at global scale. Normalized Difference Vegetation Index (NDVI) were derived from Sentinel-2 data. NDVI and NDVI based spectral diversity/heterogeneity indices were selected as predictive variables, and alpha diversity indices were selected as response variables. Simple linear regression (SLR), partial linear regression (PLSR), and random forest (RF) models were used to evaluate the predictive ability of the predictive variables against the response variables under six ecosystems (evergreen broadleaved forest (EBF), DBF, ECF, DCF, shrub, and grassland), and to compare the estimated robustness of various spectral diversity indices. In terms of prediction accuracy, the SLR models were the worst, and the PLSR model were average. RF performed best, outperforming most current models. Especially in DBF, ECF, shrub and grassland, the determination coefficient R2 of RF models can be as high as 0.9. In terms of the prediction of α-diversity, the prediction effect of species richness was better than that of Shannon index, Simpson index and Pielou index. The higher the vegetation complexity, the more accurate the assessment of vegetation α-diversity tends to be, especially in DBF, shrub and grassland. According to the importance of predictive variables and model stability evaluation results, NDVI, standard deviation of NDVI (SD), and NDVI derived Shannon’s diversity index (Sha), Cumulative Residual Entropy (CRE), Pielou’s evenness index (Pie), Hill’s numbers (Hill), Berger-Parker’s diversity index (Ber), Parametric Rao’s index of quadratic entropy(paRao) are all powerful indicators for predicting plant alpha diversity. Among them, the prediction performance of NDVI and SD is better. This study is not only an exploration of the practicability of R package “rasterdiv”, but also an attempt to construct high-precision remote sensing estimation models of plant alpha diversity at global scale.

Increased Soil Moisture in the Wet Season Alleviates the Negative Effects of Nitrogen Deposition on Soil Microbial Communities in Subtropical Evergreen Broad-Leaved Forest

Increased Soil Moisture in the Wet Season Alleviates the Negative Effects of Nitrogen Deposition on Soil Microbial Communities in Subtropical Evergreen Broad-Leaved Forest

Evolvement of Spatio-Temporal Pattern and Driving Forces Analysis of Ancient Trees Based on the Geographically Weighted Regression Model in Guangzhou and Foshan, China

Ancient trees play an important ecosystem service role in high-density cities, revealing the zonal distribution characteristics of vegetation under climate influence. The ancient trees in Guangzhou and Foshan in 2018 and 2023 were taken as study objects to explore the evolution of their spatio-temporal patterns and to analyze the spatial differentiation characteristics of their driving factors using the geographical weighted regression (GWR) model. The results showed the following: (1) The ancient trees in Guangzhou and Foshan were composed of typical subtropical evergreen broad-leaved forest communities, mainly represented by broad-leaved species of evergreen dicotyledonous plants. The dominant species mainly included Litchi chinensis, Ficus microcarpa, Canarium pimela, Ficus virens, and Dimocarpus longan. However, there was a significant difference between Guangzhou and Foshan. (2) The number of ancient trees in Guangzhou showed negative growth, while Foshan saw a significant increase. However, species diversity in both areas increased, with the highest diversity in the northeast, higher diversity in the south-central part, and lower diversity in the western and northwestern parts. (3) The maximum kernel density of ancient trees in Guangzhou and Foshan differed 22-fold, indicating a spatial distribution pattern of multiple clusters. (4) The GWR model effectively explained the driving factors of the heterogeneity of the spatial distribution of ancient trees. The results showed that artificial disturbance was the most important factor affecting the spatial distribution of ancient trees in high-density urban agglomerations in the same vegetation zone. The study clarified the characteristics of the spatial distribution and species diversity of ancient trees in the region, revealed the driving factors for the evolution of the spatial pattern of ancient trees in highly urbanized areas, and provided guidelines for policies and measures for enhancing biodiversity and conserving germplasm resources in the region.

Responses of Soil Organic Carbon Fractions and Stability to Forest Conversion in the Nanling Nature Reserve, China

Studying the impact of typical vegetation types in forest conversion zones on soil organic carbon (SOC) structure and stability is crucial for developing terrestrial ecosystem carbon sequestration strategies. In this study, we selected three typical forest stands in the Nanling National Nature Reserve: a primary evergreen broad-leaved forest (BL), a secondary mixed coniferous and broad-leaved forest (ML), and a Chinese fir plantation (CL). Soil samples were collected to examine the SOC fractions and carbon pool management index (CPMI) in three forest stands. The influence of soil property factors on SOC fractions was also analyzed. The results showed that the transformation process from a BL to an ML or a CL changed the structure and stability of organic carbon by reducing the labile SOC fractions and increasing the recalcitrant carbon fraction in the soil. The higher lability index (LI) and CPMI of soils in the BL indicated better carbon accumulation and activity, making this treatment more advantageous for management strategies aimed at promoting natural forest renewal and ecological restoration. Correlation and RDA analysis revealed that the availability of soil P was a key factor limiting the variation in organic C fractions in the acidic soils of tropical forests in South China.

Impact of extreme pre-monsoon drought on xylogenesis and intra-annual radial increments of two tree species in a tropical montane evergreen broad-leaved forest, southwest China.

Tropical montane evergreen broad-leaved forests cover the majority of forest areas and have high carbon storage in Xishuangbanna, southwest China. However, stem radial growth dynamics and their correlations with climate factors have never been analyzed in this forest type. By combining bi-weekly microcoring and high-resolution dendrometer measurements, we monitored xylogenesis and stem radius variations of the deciduous species Betula alnoides Buch.-Ham. ex D. Don and the evergreen species Schima wallichii (DC.) Korth. We analyzed the relationships between weekly climate variables prior to sampling and the enlarging zone width or wall-thickening zone width, as well as weekly radial increments and climate factors during two consecutive years (2020 to 2021) showing contrasting hydrothermal conditions in the pre-monsoon season. In the year 2020, which was characterized by a warmer and drier pre-monsoon season, the onset of xylogenesis and radial increments of B. alnoides and S. wallichii were delayed by three months and one month, respectively, compared with the year 2021. In 2020, xylem formation and radial increments were significantly reduced for B. alnoides, but not for S. wallichii. The thickness of enlarging zone and wall-thickening zone in S. wallichii were positively correlated with relative humidity, and minimum and mean air temperature, but were negatively correlated with vapor pressure deficit during 2020 to 2021. The radial increments of both species showed significant positive correlations with precipitation and relative humidity, and negative correlations with vapor pressure deficit and maximum air temperature during two years. Our findings reveal that drier pre-monsoon conditions strongly delay growth initiation and reduce stem radial growth, providing deep insights to understand tree growth and carbon sequestration potential in tropical forests under a predicted increase in frequent drought events.

Genome-Wide Identification, Evolution, and Expression Analysis of the DIR Gene Family in Schima superba.

Schima superba, commonly known as the Chinese guger tree, is highly adaptable and tolerant of poor soil conditions. It is one of the primary species forming the evergreen broad-leaved forests in southern China. Dirigent proteins (DIRs) play crucial roles in the synthesis of plant lignin and lignans, secondary metabolism, and response to adversity stress. However, research on the DIR gene family in S. superba is currently limited. This study identified 24 SsDIR genes, categorizing them into three subfamilies. These genes are unevenly distributed across 13 chromosomes, with 83% being intronless. Collinearity analysis indicated that tandem duplication played a more significant role in the expansion of the gene family compared to segmental duplication. Additionally, we analyzed the expression patterns of SsDIRs in different tissues of S. superba. The SsDIR genes exhibited distinct expression patterns across various tissues, with most being specifically expressed in the roots. Further screening identified SsDIR genes that may regulate drought stress, with many showing differential expression under drought stress conditions. In the promoter regions of SsDIRs, various cis-regulatory elements involved in developmental regulation, hormone response, and stress response were identified, which may be closely related to their diverse regulatory functions. This study will contribute to the further functional identification of SsDIR genes, providing insights into the biosynthetic pathways of lignin and lignans and the mechanisms of plant stress resistance.

Feeding Habits of Japanese Serow in a Warm–Temperate, Low-Elevation, Evergreen Broad-Leaved Shrub-Dominated Forest

Feeding Habits of Japanese Serow in a Warm–Temperate, Low-Elevation, Evergreen Broad-Leaved Shrub-Dominated Forest

Heterogeneous occurrence of evergreen broad-leaved forests in East Asia: Evidence from plant fossils

Evergreen broad-leaved forests (EBLFs) are widely distributed in East Asia and play a vital role in ecosystem stability. The occurrence of these forests in East Asia has been a subject of debate across various disciplines. In this study, we explored the occurrence of East Asian EBLFs from a palaeobotanical perspective. By collecting plant fossils from four regions in East Asia, we have established the evolutionary history of EBLFs. Through floral similarity analysis and paleoclimatic reconstruction, we have revealed a diverse spatio-temporal pattern for the occurrence of EBLFs in East Asia. The earliest occurrence of EBLFs in southern China can be traced back to the middle Eocene, followed by southwestern China during the late Eocene–early Oligocene. Subsequently, EBLFs emerged in Japan during the early Oligocene and eventually appeared in central-eastern China around the Miocene. Paleoclimate simulation results suggest that the precipitation of wettest quarter (PWetQ, mm) exceeding 600 mm is crucial for the occurrence of EBLFs. Furthermore, the heterogeneous occurrence of EBLFs in East Asia is closely associated with the evolution of the Asian Monsoon. This study provides new insights into the occurrence of EBLFs in East Asia.

Early Paleogene plant biomes of the Pacific side of Eurasia

Major plant biome changes in East Asia during the early Paleogene are studied using the Integrated Plant Record vegetation analysis for the first time based on paleobotanical records. The paleobotanical record employed for the reconstruction comprises 110 paleofloras covering the early Paleocene to early Eocene, a time-span of ca. 17 Myr. Our data indicate the presence of more forested conditions over East Asia during the early Paleogene than at present. The early Paleogene vegetation cover in the study area fundamentally differed from modern and was much more homogeneous compared to the modern one. Mixed mesophytic zonal vegetation dominated on the Pacific side of Eurasia during the early Paleogene. Thermophilous mixed mesophytic forests were distributed even at very high latitudes, but at the same time, ecotone between the mixed mesophytic / broadleaved evergreen forests and broadleaved evergreen forest were confined to regions south of 50°N. The proportions of sclerophyllous plants are low in general, even in the mid-latitudes. The localities with open woodlands are all located south of ca. 45°N. The observed vegetation patterns and their changes throughout the early Paleogene in many cases can be correlated with climate patterns and the overall continental paleoclimate evolution as reconstructed from the paleobotanical record. The higher-than-present spatial homogeneity of early Paleogene vegetation coincides with shallow temperature gradients and a significantly more humid regional rainfall pattern over East Asia during the early Paleogene.

Solar Radiation Triggers the Bimodal Leaf Phenology of Central African Evergreen Broadleaved Forests

AbstractCentral African evergreen broadleaved forests around the equator exhibit a double annual cycle for canopy phenology and carbon uptake seasonality. The underlying drivers of this behavior are poorly understood and the double seasonality is not captured by land surface models (LSM). In this study, we developed a new leaf phenology module into the ORCHIDEE LSM (hereafter ORCHIDEE‐AFP), which utilizes short‐wave incoming radiation (SWd) as the main driver of leaf shedding and partial rejuvenation of the canopy, to simulate the double seasonality of central African forests. The ORCHIDEE‐AFP model has been evaluated by using field data from two forest sites and satellite observations of the enhanced vegetation index (EVI), which is a proxy of young leaf area index (LAIYoung) with leafage less than 6 months, as well as six products of GPP or GPP proxies. Results demonstrate that ORCHIDEE‐AFP successfully reproduces observed leaf turnover (R = 0.45) and young leaf abundance (R = 0.74), and greatly improve the representation of the bimodal leaf phenology. The proportion of grid cells with a significant positive correlation between the seasonality of modeled LAIYoung and observed EVI increased from 0.2% in the standard model to 27% in the new model. For photosynthesis, the proportions of grid cells with significant positive correlations between modeled and observed seasonality range from 26% to 65% across the six GPP evaluation products. The improved performance of the ORCHIDEE‐AFP model in simulating leaf phenology and photosynthesis of central African forests will allow a more accurate assessment of the impacts of climate change in tropical forests.