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Specimens of Amanita sect. Caesareae, collected in Xieng Khouang and Vientiane provinces in Laos from highland forests dominated by members of Fagaceae and Pinaceae, are studied based on morphological characters and analyses of ITS sequences. Two species, namely A. princepoides and A. chepangianoides, are reported as new, both found in association with Fagaceae, whereas A. pseudoprinceps and A. subhemibapha, recently described from China and A. rubromarginata from Japan, are confirmed from Laos and found in forests with Fagaceae and Pinaceae. The phylogenetic analyses to recognize the Amanita species showed that the golden-brown to greyish orange A. princepoides and the dominantly white A. chepangianoides cluster with A. aporema, A. chepangiana, A. egregia, A. princeps and A. pseudoprinceps. A dichotomous key to identified and likely occurring Amanita species in Laos within sect. Caesareae is also provided. [ABSTRACT FROM AUTHOR]

• Tsuga leaves were reported from the Neogene Baoshan Basin in southwest China. • Morphological comparison and cluster analysis suggest their close affinity to T. dumosa. • The fossil find suggests a humid climate in the basin at the time of fossil deposition. • The leaf epidermal micromorphology is important in taxonomy of Tsuga fossil leaves. Tsuga (Endl.) Carrière (Pinaceae) has a rich fossil record represented by pollen, leaves, wood and seed cones. Although fossil leaves of the genus have been widely documented, most of them have not been examined microscopically, which may limit their taxonomic resolution. In this study, three-dimensionally preserved leaves and leaf fragments of Tsuga from the Neogene (latest Miocene to Pliocene) Baoshan Basin in western Yunnan, southwest China, were examined both morphologically and micromorphologically. The fossil leaves are characterized by flattened and bifacial shape, round to obtuse apex and petiolate base, adaxially sunken and abaxially elevated midvein, adaxial surface without stomata and with elongated, smooth-margined epidermal cells, and abaxial surface with two stomatal bands along the midvein, each stomatal band consisting of 6–8 longitudinal stomatal lines. Based on comparisons with extant species of the genus, we found that the fossil leaves show the closest affinity to Tsuga dumosa (D. Don) Eichler, an extant species growing in the modern western Yunnan. As modern species of Tsuga prefer humid conditions, our fossil find suggests a humid climate in the Baoshan Basin at the time of fossil deposition, probably due to the influence of the Indian summer monsoon from the southwest. This is consistent with previous results of quantitative palaeoclimate reconstructions using spore/pollen fossil assemblages. Our study provides new fossil evidence for the origin of modern conifer diversity in southwest China. It highlights the importance of microscopic studies in the taxonomic resolution of fossil leaves of Pinaceae. [ABSTRACT FROM AUTHOR]

Following the invasion by the pine wood nematode (PWN) into north‐east China, a notable disparity in susceptibility was observed among Pinaceae species. Larix olgensis exhibited marked resilience and suffered minimal fatalities, while Pinus koraiensis experienced significant mortality due to PWN infection. Our research demonstrated that the PWNs in L. olgensis showed a 13.43% reduction in lipid content compared to P. koraiensis (p < 0.05), which was attributable to the accumulation of caffeic acid in L. olgensis. This reduction in lipid content was correlated with a decreased overwintering survival of PWNs. The diminished lipid reserves were associated with substantial stunting in PWNs, including reduced body length and maximum body width. The result suggests that lower lipid content is a major factor contributing to the lower overwintering survival rate of PWNs in L. olgensis induced by caffeic acid. Through verification tests, we concluded that the minimal fatalities observed in L. olgensis could be attributed to the reduced overwintering survival of PWNs, a consequence of caffeic acid‐induced stunting. This study provides valuable insights into PWN–host interactions and suggests that targeting caffeic acid biosynthesis pathways could be a potential strategy for managing PWN in forest ecosystems. [ABSTRACT FROM AUTHOR]

The editorial "Topicalities in the Forest Ecology of Seeds" focuses on the importance of forest seed farming to ensure a sufficient number of high genetic value fruit/seeds for tree species management. The special issue covers topics such as seed dormancy, desiccation tolerance, complex bioecological studies, and reproductive capacity in forestry. The articles provide valuable insights into the biological and ecological aspects of seeds, offering a scientific basis for forestry and nature conservation practices to enhance forest ecosystem health and biodiversity in the face of environmental challenges. [Extracted from the article]

Volatile organic compounds (VOCs) and essential oils of conifers are widely used in the pharmaceutical industry. This work aimed to analyze the VOCs of 30 conifer species representing the Pinaceae and Cupressaceae families. Samples were collected from arboreta in Hungary, and their chemical composition was determined by gas chromatography (SPME-GC/MS); then, chemometric analyses were performed using multivariate methods to identify characteristic VOCs of conifers. Here, we present results for monoterpene and sesquiterpene profiles of the examined conifer samples. The most abundant compounds detected were α-pinene, bornyl acetate, limonene, β-pinene, β-caryophyllene, β-myrcene, δ-3-carene, and β-phellandrene. The results showed that the following volatiles were characteristic of the conifer groups: sabinene (RRT=6.0) for the cupressoid group (which includes the Cupressaceae species), longifolene (RRT=15.0) and β-pinene (RRT=6.1) were characteristic of the pinoid group (including Picea, Pinus, and Pseudotsuga species), and camphene (RRT=5.5) and bornyl acetate (RRT=12.6) were characteristic of the abietoid group (including Abies, Cedrus, and Tsuga species). Our results on VOCs in the Pinaceae and Cupressaceae families contribute to the elucidation of biodiversity patterns of conifer species and, in addition, may support the industrial application of terpenes. [ABSTRACT FROM AUTHOR]

North American conifers exhibit three radial specific gravity (SG) patterns (Type 1, 2, and 3), which balance hydraulic and mechanical requirements. Type 1 and 2 patterns (Pinaceae) have low SG and high microfibril angle (MFA) corewood ensuring compliance, whereas in outerwood high SG/low MFA provide stiffness and strength resisting bending. Hydraulically, corewood, especially in Type 2 species, is resistant to embolism, whereas outerwood has higher specific conductivity. Cupressaceae (Type 3) have hydraulically very efficient, low SG outerwood, facilitating rapid growth. Corewood is flexible, whereas outerwood is mechanically weak and compensated for by more conical stems and durable heartwood (which prevents Brazier buckling). Radially earlywood (EW) decreases, and latewood (LW) increases for all types, whereas %latewood (%LW) increases (Type 1), decreases, then increases (Type 2) and decreases (Type 3). Ring SG increases when increasing LW SG and %LW are sufficient to counteract decreasing EW SG. Shade tolerance, crown recession, hormone gradients, and environmental variation affect patterns. Auxin concentration decreases with increasing distance from juvenile foliage slowing cell division, concomitantly gibberellin concentration (lignification) and carbohydrates (cell wall thickening) increase, producing higher %LW. Across a species range regions receiving relatively high summer rainfall have trees with higher %LW (by ring). [ABSTRACT FROM AUTHOR]

Proper management of woody ecosystems is fundamental for human livelihoods and biodiversity conservation. Strip cutting or selective harvesting are proposed as sustainable alternatives to clear-cut logging. However, their impacts are not fully understood, especially when we consider the harvesting intensity levels and the invasibility of an ecosystem by nonnative tree species. In this study we analyzed the impacts of different harvesting intensity levels on the establishment after 2 years of nonnative and native tree species. We conducted this study in a mixed forest dominated by Nothofagus antarctica, where we applied four strip harvesting levels: 0% (control), 30%, 50% and 70% percentage of vegetation removal in eight plots (1417.5 m2 each plot) Inside those plots, we had a total of 24 subplots (3 sites × 8 plots) were we sowed seeds of a total of six tree species, that can form dominant stands in the studied region. Three species were nonnative invasives in the region (Pinus ponderosa, Pinus contorta and Pseudotsuga mensiezii), and the other three were native species (Austrocedrus chilensis, Nothofagus obliqua and Araucaria araucana). We found that in the high harvesting intensity treatments, the establishment after 2 years of all nonnative trees and only one native species (A. araucana) was increased in spite of the ecological and structural differences (i.e., productivity levels) between sites. Invasion by nonnative tree species can have important negative economic and ecological consequences on the logged ecosystems, so their removal may be required to keep them away from colonizing and dominating the logged areas, especially at high harvesting intensities. [ABSTRACT FROM AUTHOR]

The masson pine (Pinus massoniana, a coniferous tree species in the pine genus of the Pinaceae family) is the largest organic carbon reservoir in southeastern China, playing an important role in regulating CO2 and maintaining the carbon-oxygen balance of the biosphere. Based on turbulence flux observation data, this study analyzed the characteristics of carbon source and sink changes and influencing factors of the masson pine in Wuyishan National Park during the growing season of 2019 from the ecosystem scale, and estimated the photosynthetic parameters under different conditions. The results showed that the net ecosystem carbon exchange (NEE) of the masson pine during the growing season was -593.06 g CO2 /m². On the daily scale, the diurnal variation of NEE of masson pine was U-shaped, and the carbon sink capacity was strongest from 12 to 14 o'clock. On a monthly scale, carbon sequestration capacity of masson pine was strongest in September (-94.55 g CO2/m²) and relatively weak from May to July. Photosynthetically active radiation was the dominant factor of NEE at night, and there was a significant negative correlation between them. Soil temperature was the dominant factor of NEE at night, and the relationship between them showed a significant quadratic function. The light response curve shows that the maximum photosynthetic rate (Pmax) of the masson pine ecosystem in March and July was higher, while the initial photosynthetic efficiency (α) of vegetation in May was higher. Both Pmax and α were larger when the vapor pressure deficit was between 1~2.5 kPa, which was the most suitable for the masson pine to absorb carbon. The increase of soil water content would lead to the increase of ecosystem respiration (Rd), α and Pmax. When soil water content was supersucated, the increment of Rd was similar to that of Pmax, and the net carbon sequestration of vegetation was no longer increasing. These results were helpful to improve the overall understanding of the carbon sink function of masson pine ecosystem. [ABSTRACT FROM AUTHOR]

Pinus mugo Turra is a coniferous species of shrub or small tree typical of central and south-eastern Europe. It is commonly called mugo pine, mountain pine, or dwarf mountain pine referring to its habit and small size. Indeed, this plant lives at higher altitude above 1400 m above the see level where it deals with harsh conditions typical of high mountain. From an ethnotraditional point of view, P. mugo is mainly used for respiratory disorders and wound healing. In particular, its essential oils have been shown to possess interesting antimicrobial and antioxidant activities, which can substantiate its potential therapeutic effect in pulmonary and urinary tract diseases, as well as antinflammatory and antitumor effects. This review also offers a summary on the chemical constituents of P. mugo that contribute to its therapeutic potential. [ABSTRACT FROM AUTHOR]

Background: Cervical cancer is a severe concern for women throughout the world. This percentage of cancer incidence causes sufferers to die at a high rate. It is believed that the bark of the Pinus merkusii tree contains anti-cancer compounds that inhibit cervical cancer cell growth. Aim: This present study aims to examine the cytotoxic ability of P. merkusii tree bark ethanol extract (PMBE) by inducing apoptosis in HeLa cells. Methods: We administered the PMBE at concentrations of 50, 100, 200, and 400 µg/mL to HeLa cell cultures. We then conducted the MTT cytotoxicity assay, detected apoptosis via Annexin V binding, and observed caspase 9 expression via immunocytochemistry. Results: PMBE showed cytotoxic activity on HeLa cells with an IC50 of 226.6 µg/mL for 24 hours of treatment. PMBE caused early apoptosis in up to 81.31% of HeLa cells, as well as increased caspase-9 expression. Conclusion: Based on this study, PMBE is predicted to have dose-dependent antiproliferative or cytotoxicity effects on the HeLa cell line through the intrinsic pathway apoptosis mechanism. [Open Vet J 2024; 14(10.000): 2628-2633]

The role of the roots and root systems of Pinus sylvestris L. in the formation of secondary pine forests in the cuttings of the Kola North was studied. It has been established that in pine seedlings in disturbed areas, root and shoot systems are formed quite quickly. Already in age class I, characteristic morphological signs of root systems appear and the feeding areas of trees begin to overlap each other. The bulk of the roots (80–85%) is concentrated in the upper 20-cm soil layer. A linear relationship between the taxation indicators of trees and the mass of root systems has been revealed. The conducted studies have shown that the formation of forest communities of Scots pine in the cuttings of the Kola North and their stability and productivity are directly dependent on the degree of development of individual roots and root systems as a whole. [ABSTRACT FROM AUTHOR]

The mutualistic interaction between trees and ectomycorrhizal fungi (EMF) can have a major effect on forest dynamics and specifically on seedling establishment. Here, we compared the EMF community composition associated with the roots of young saplings and mature trees of two co-habiting Pinaceae: Pinus halepensis and Cedrus deodara growing together in a post-fire forest plot, using fungal ITS metabarcoding. We found that the differences in the EMF community between the two sapling groups were mostly attributed to changes in the relative abundance of specific fungal species, with little species turnover. Specifically, Tomentella showed high abundance on pine roots, while Tuber , Russula and Sebacina were more common on the roots of cedars. The physical proximity to a specific host species was correlated with the EMF community composition of young saplings. Specifically, regardless of the sapling's own identity, the roots of saplings growing next to mature cedars had higher abundance of Tuber species, while Tomentella coerulea (Höhn. & Litsch) , Russula densifolia (Secr. ex Gillet) and Tuber nitidum (Vittadini) dominated saplings next to mature pines. Cedar saplings' shoot structure was correlated with a specific EMF species. Overall, these results suggest that when germinating next to mature trees, the EMF community of saplings could be determined by extrinsic factors such as the small-scale distribution of mature trees in the forest. [ABSTRACT FROM AUTHOR]

Aim: Efforts to understand how pollinating insect diversity is distributed across large geographic areas are rare despite the importance of such work for conserving regional diversity. We sought to relate the diversity of bees (Hymenoptera: Apoidea), hover flies (Diptera: Syrphidae), and butterflies (Lepidoptera) to ecoregion, landscape context, canopy openness, and forest composition across southeastern U.S. forests. Location: Nineteen experimental forests across nine states in the southeastern U.S. Methods: We established 5–7 plots on each experimental forest. In each, we sampled pollinators monthly (March–September) using coloured pan traps, and collected data on local forest characteristics. We used the National Land Cover Database (NLCD) to quantify surrounding landcover at different spatial scales. Results: Bee richness was negatively correlated with both the amount of conifer (pine) forest and the extent of wetlands in the surrounding landscape but was positively correlated with canopy openness. Hover flies and butterflies were less sensitive to landscape context and stand conditions. Pollinator communities differed considerably among ecoregions, with those of the Central Appalachian and Coastal Plain ecoregions being particularly distinct. Bee richness and abundance peaked 2 months earlier in Central Appalachia than in the Coastal Plain and Southeastern Mixed Forest ecoregions. Main Conclusions: Our findings reveal ecoregional differences in pollinator communities across the southeastern U.S. and highlight the importance of landscape context and local forest conditions to this diverse fauna. The closed broadleaf forests of Appalachia and the open conifer‐dominated forests of the Coastal Plain support particularly distinct pollinator communities with contrasting seasonality. Our results suggest pine forests may reduce pollinator diversity in regions historically dominated by broadleaf forests. However, efforts to create more open canopies can help improve conditions for pollinators in planted pine forests. Research exploring associations between forest pollinators and different broadleaf tree taxa is needed to better anticipate the impacts of various management activities. [ABSTRACT FROM AUTHOR]

The spatial differentiation of forest canopy branches and leaves affects rainfall interception. However, the scientific expression of the spatial differentiation of forest canopy branches and leaves has not been clarified, and revealing the effect of spatial differentiation of branches and leaves of the vertical structure of the forest canopy on rainfall interception is difficult. Using the Pinus massoniana planted in Changting County, China, as the research object, this study quantified the spatial differentiation of canopy branches and leaves in a hierarchical manner by combining the unmanned aerial vehicle (UAV) three-dimensional point cloud model with the landscape metrics and further simulated the interception mechanism of Pinus massoniana forest canopy on rainfall of different intensities by constructing the principal component regression model. The results showed that the spatial differentiation of canopy branches and leaves in different strata responds differently to different rainfall intensities. [ABSTRACT FROM AUTHOR]

Studies of needle xylem structure (NXS) are of importance in understanding the survival, and functioning of conifers, particularly in response to environmental stressors. Herein, I review the current state-of-the-art about the NXS of genus Pinus, focusing on the xylem, tracheid, and pit structure. Genus Pinus is one of the most important and widely distributed genera of forest trees in the Northern Hemisphere. Pine species are adapted to different soil types and extreme environments imposed by elevation and latitude. They grow successfully in the boreal forest, the Mediterranean Basin, and in mountains. The importance of NXS for long-distance water transport in trees is discussed and the relationships between xylem structure and function are highlighted. Little is known about the NXS of pines, as such information was available only for 12 pine species. Moreover, current knowledge about the NXS of pines is mostly based on Pinus sylvestris L., especially regarding the effect of environmental conditions on NXS. So far, tracheid pit structure has been investigated in only one study. Although NXS is also significantly influenced by tree age, the position of needles within the crown, as well as the location of the cross-section along the longitudinal axis of the needle, a detailed needle sampling design is often missing. Hence, it is suggested to extend future studies to other pine species to explain their resistance to drought and cold. Additionally, increasing the number of studies on adult trees and distinguishing between the different types of environmental stress that a tree can face during its life cycle would be beneficial. I strongly appeal to precise description of needle sampling, which will allow us both intraspecific and interspecific comparisons. Increasing knowledge about the NXS of pines will help to better explain their resistance to environmental stress and predict their tolerance to future climate change. [ABSTRACT FROM AUTHOR]

Twisted trunks are not uncommon in trees, but their effects on tree growth are still unclear. Among coniferous tree species, the phenomenon of trunk distortion is more prominent in Pinus yunnanensis. To expand the germplasm of genetic resources, we selected families with excellent phenotypic traits to provide material for advanced generation breeding. The progeny test containing 93 superior families (3240 trees) was used as the research material. Phenotypic measurements and estimated genetic parameters (family heritability, realistic gain and genetic gain) were performed at 9, 15, and 18 years of age, respectively. The genetic evaluation yielded the following results (1) The intra-family variance component of plant height (PH) was greater than that of the inter-family, while the inter-family variance components of other traits (diameter at breast height (DBH), crown diameter (CD), height under branches (HUB), degree of stem-straightness (DS)) were greater than that of the intra-family, indicating that there was abundant variation among families and potential for selection. (2) At half rotation period (18 years old), there was a significant correlation among the traits. The proportion of trees with twisted trunks (level 1–3 straightness) reached 48%. The DS significantly affected growth traits, among which PH and DBH were the most affected. The volume loss rate caused by twisted trunk was 18.06-56.75%, implying that trunk distortion could not be completely eliminated after an artificial selection. (3) The influence of tree shape, crown width, and trunk on volume increased, and the early-late correlation between PH, DBH and volume was extremely significant. The range of phenotypic coefficient of variation, genetic variation coefficient and family heritability of growth traits (PH, DBH, and volume) were 44.29-127.13%, 22.88-60.87%, and 0.79–0.83, respectively. (4) A total of 21 superior families were selected by the method of membership function combined with independent selection. Compared with the mid-term selection (18 years old), the accuracy of early selection (9 years old) reached 77.5%. The selected families' genetic gain and realistic gain range were 5.79-19.82% and 7.12-24.27%, respectively. This study can provide some useful reference for the breeding of coniferous species. [ABSTRACT FROM AUTHOR]

In long-lived species, deforestation can modify the genetic diversity patterns of recent populations. The spatial-structure genetics of Pinus leiophylla Schiede ex Schltdl. & Cham. was investigated in adults and seedlings of remnant populations from central Mexico. Two chloroplast intergenic regions were sequenced of two cohorts (adults and seedlings) of 121 individuals of P. leiophylla from three localities. Higher genetic differentiation was found in adults (ФST = 0.09) than in seedlings (ФST = 0.03). The discriminant analysis of principal components detected four genetic clusters and the Mantel test found a weak but significant isolation by distance pattern (r2 = 0.05, p = 0.002). Sixteen percent of genetic variation was explained by the spatial component according to the genetic neighborhood analysis. And the effect of three landscape features, i.e., elevation, aspect (sine and cosine), and land use, explored with ResistanceGA, detected that land use significantly restricts gene flow between populations, mostly in the farming category. This study emphasizes the critical role of preserving forest cover to maintain connectivity among remnants of P. leiophylla. Insights of this study will contribute to the conservation of conifers in Mexican temperate forests, especially within landscapes heavily altered by human activities. [ABSTRACT FROM AUTHOR]

Pollen, plant macrofossils and charcoal analyses were used to study tree diversity, fire history and forest disturbance over the past c. 3500 years at three forest remnant sites in Vendsyssel, northern Denmark. All locations had a more diverse tree composition in the past including abundant Alnus, Betula, Corylus, Pinus, Quercus, Salix, Tilia and Ulmus. The changes in tree diversity through time can be attributed to a combination of factors including climate change, burning linked to shifting cultivation, grazing and felling. The balance between arboreal and non-arboreal pollen was already being influenced by human activities in the late Bronze Age c. 3000 years ago. The high pollen abundance values recorded for Tilia pre-2000 years ago are exceptional as compared to later periods at these sites. At one location, the transition from Tilia to Fagus indicated that Tilia prevailed until c. 1300 years ago. Subsequent periods of forest clearance, with charcoal and cereal cultivation, initially including Hordeum and subsequently also Secale, were recorded. There was pollen evidence for grazing followed by shrub regeneration including Calluna, Erica, Juniperus and herbaceous taxa, and following that, a forest recovery of mainly Fagus, Picea and Pinus. This recovery is also recorded in historical forest records from 1880 CE onwards, emphasising the dominant role of plantation schemes. Results are placed in a wider framework of other sites in Denmark and southern Scandinavia, which have also documented a reduction of tree diversity and forest cover over the same period. The evidence from the long-term record is used to draw conclusions to assist forest restoration programmes. [ABSTRACT FROM AUTHOR]

The nurse effect is a positive interaction in which a nurse plant improves the abiotic environment for another species (beneficiary plant) and facilitates its establishment. The evergreen shrub Vaccinium vitis-idaea (a beneficiary plant) grows mainly under the dwarf shrub Pinus pumila (a nurse plant) in the alpine regions of central Japan. However, whether V. vitis-idaea shrubs under various P. pumila shrubs spread through clonal growth and/or seeds remains unclear. We investigated the clonal structure of V. vitis-idaea under the nurse plant P. pumila in Japanese alpine regions. MIG-seq analysis was conducted to clarify the clonal diversity of V. vitis-idaea in isolated and patchy P. pumila plots on a ridge (PATs), and in a plot covered by dense P. pumila on a slope adjacent to the ridge (MAT) on Mt. Norikura, Japan. We detected 28 multilocus genotypes in 319 ramets of V. vitis-idaea across 11 PATs and MAT. Three genets expanded to more than 10 m in the MAT. Some genets were shared among neighboring PATs or among PATs and MAT. These findings suggest that the clonal growth of V. vitis-idaea plays an important role in the sustainability of populations. The clonal diversity of V. vitis-idaea was positively related with the spatial size of PATs and was higher in MAT than in PATs at a small scale. Therefore, the spatial spread of the nurse plant P. pumila might facilitate the nurse effect on the genetic diversity of beneficiary plants, leading to the sustainability of beneficiary populations. [ABSTRACT FROM AUTHOR]

The flexural behavior of hybrid timber–steel encased beams comprising coniferous radiata pine (Pinus radiata) (MGP10) and Douglas fir (Pseudotsuga menziesii) (F8) timber lamellae with bonded-in steel bars is studied. The effect of cross-section depth, steel bar size, timber species/grade, and steel bar arrangements (only bottom and top-and-bottom) on the hybrid beams' stiffness, failure mode, ductility, and load-carrying capacity were investigated. The flexural capacity and stiffness of the doubly (top-and-bottom) reinforced beams are increased by 127% and 71%, respectively. However, in the singly (bottom) reinforced beams, the flexural capacity and stiffness are increased only by 41% and 25%, respectively, highlighting the important role of the compressive bars. The failure of all beams was associated with tensile flexural failure of timber, but the steel bars improved the ductility of the beams. The maximum coefficient of variation of the peak load in hybrid beams (CoV=14.3%) is lower than that of the bare timber beams (CoV=21.7%). Two analytical models were developed based on a linear and a bilinear stress–strain relationship for timber. The analytically predicted peak load and stiffness agree well (less than 13% and 12% difference) with the experimental results. [ABSTRACT FROM AUTHOR]

Aim: Climate change is altering habitat suitability for many organisms and modifying species ranges at a global scale. Here we explored the impact of climate change on 112 pine species (Pinus), fundamental elements of Northern terrestrial ecosystems. Location: Global. Methods: We applied a novel methodology for species distribution modelling that considers uncertainty in climatic projections and taxon sampling, and incorporates elements of species' recent evolutionary history. We based our niche calculations on climate and soil data and computed projections across multiple algorithms and IPCC scenarios, which were ensembled into one single suitability map. We then used phylogenetic methods to account for recent evolution in climatic requirements by estimating the evolution of climatic niche. Edaphoclimatic and evolutionary analyses were then combined to calibrate the projections in areas showing high uncertainty. We validated our models using naturalized occurrences of invasive pine species. Results: Our models predicted that by 2070, most pine species (58%) might face important reductions of habitat suitability, potentially leading to range losses and a decrease in species richness, particularly in some regions such as the Mediterranean Basin and South North America, albeit migration might mitigate these shifts in some cases. In contrast, our projections showed increased habitat suitability for approx. 20% of species, which may undergo range expansions under climate change. Moreover, the consideration of recent evolutionary trends modified projected scenarios, decreasing range loss and increasing range expansion for some species. The independent validation endorsed our models for many species and the influence of recent evolution in some cases. Conclusions: We predict that climate change will impose drastic changes in pine distribution and diversity across biogeographical regions, but the magnitude and direction of change will vary significantly across regions and taxa. Species‐level responses are likely to be influenced by regional conditions and the recent evolutionary history of each taxon. [ABSTRACT FROM AUTHOR]

Pollen cones of Araucaria araucana and Wollemia nobilis were investigated. They consist of hundreds of hyposporangiate microsporangiophores with numerous microsporangia, arranged in up to three abaxial rows. Convincing evidence was found that excludes the widely accepted sporophyll concept of coniferous microsporangiophores. It is shown that the units treated generally as sporophylls in fact represent a complex fusion product of numerous microsporangiophores (= synangia). The vasculature in the microsporangiophore may indicate that the hyposporangiate shape is derived from an ancestral perisporangiate condition. In particular, the bundle strands ending blindly in the tissue in distal parts of the scutellum can only be understood as belonging to aborted microsporangia. Transferring this concept to other conifers with hyposporangiate microsporangiophores a perisporangiate origin seems also highly likely for them. This is well supported by the fact that in usually hyposporangiate taxa occasionally perisporangiate microsporangiophores are developed. Thus, the gained results clearly indicate that each microsporangiophore corresponds to a lateral cone (= flower equivalent structure), and the entire pollen cone to a compound structure (= inflorescence equivalent structure). Thus, the evolutionary pathway of araucariaceous pollen cones fits well to the pseudanthial origin suggested previously for the male reproductive structures in other coniferous groups, e.g., Pinaceae or Taxaceae. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Efficient mitigation of climate change requires predictive models of forest ecosystems as sinks for atmospheric carbon. Mycorrhizal fungi are drivers of soil carbon storage in boreal forests, yet they are typically excluded from ecosystem models, because of a lack of information about their growth and turnover. Closing this knowledge gap could help us better predict future responses to climate change and guide policy decisions for sustainable management of forest ecosystems. This study provides new estimates of the production and turnover of mycorrhizal mycelial biomass and necromass. This information can facilitate the integration of mycorrhizal fungi into new predictive models of boreal forest soils. Summary: In boreal forests, turnover of biomass and necromass of ectomycorrhizal extraradical mycelia (ERM) are important for mediating long‐term carbon storage. However, ectomycorrhizal fungi are usually not considered in ecosystem models, because data for parameterization of ERM dynamics is lacking.Here, we estimated the production and turnover of ERM biomass and necromass across a hemiboreal Pinus sylvestris chronosequence aged 12 to 100 years. Biomass and necromass were quantified in sequentially harvested in‐growth bags, and incubated in the soil for 1–24 month, and Bayesian calibration of mathematical models was applied to arrive at parametric estimates of ERM production and turnover rates of biomass and necromass.Steady states were predicted to be nearly reached after 160 and 390 growing season days, respectively, for biomass and necromass. The related turnover rates varied with 95% credible intervals of 1.7–6.5 and 0.3–2.5 times yr−1, with mode values of 2.9 and 0.9 times yr−1, corresponding to mean residence times of 62 and 205 growing season days.Our results highlight that turnover of necromass is one‐third of biomass. This together with the variability in the estimates can be used to parameterize ecosystem models, to explicitly include ERM dynamics and its impact on mycorrhizal‐derived soil carbon accumulation in boreal forests. [ABSTRACT FROM AUTHOR]

Introduction: Abscisic acid (ABA) can negatively regulate seed germination, but the mechanisms of ABA-mediated metabolism modulation are not well understood. Moreover, it remains unclear whether metabolic pathways vary with the different tissue parts of the embryo, such as the radicle, hypocotyl and cotyledon. Methods: In this report, we performed the first comprehensive metabolome analysis of the radicle and hypocotyl + cotyledon in Pinus koraiensis seeds in response to ABA treatment during germination. Results and discussion: Metabolome profiling showed that following ABA treatment, 67 significantly differentially accumulated metabolites in the embryo were closely associated with pyrimidine metabolism, phenylalanine metabolism, cysteine and methionine metabolism, galactose metabolism, terpenoid backbone biosynthesis, and glutathione metabolism. Meanwhile, 62 metabolites in the hypocotyl + cotyledon were primarily involved in glycerophospholipid metabolism and glycolysis/gluconeogenesis. We can conclude that ABA may inhibit Korean pine seed germination primarily by disrupting the biosynthesis of certain plant hormones mediated by cysteine and methionine metabolism and terpenoid backbone biosynthesis, as well as reducing the reactive oxygen species scavenging ability regulated by glutathione metabolism and shikimate pathway in radicle. ABA may strongly disrupt the structure and function of cellular membranes due to alterations in glycerophospholipid metabolism, and weaken glycolysis/gluconeogenesis in the hypocotyl + cotyledon, both of which are major contributors to ABAmediated inhibition of seed germination. These results highlight that the spatial modulation of metabolic pathways in Pinus koraiensis seeds underlies the germination response to ABA. [ABSTRACT FROM AUTHOR]

Classifying fungus based on morphological traits is an effective strategy to distinguish between puffballs, earthballs, earthstars, and other gasteroid fungi, as well as for identifying sub-groups of closely related taxon. However, to delimitate taxa it should be addressed with caution, since cryptic species have been described recently in different genera of gasteroid fungi. Astraeus is a star-shaped fungus that has piqued the interest of mycologists worldwide, including India. These endearing fungi have tremendous nutritional and therapeutic benefits, but their molecular and phylogenetic placement in India is uncertain. An integrative taxonomic approach was used to identify and resolve ambiguities within the genus. This study, the first to elucidate the distribution, taxonomy, and phylogeny of the genus Astraeus in the mixed subtropical Pinus-Shorea forest and tropical dry deciduous Shorea dominated forest in India, aims to shed light on these indispensable ectomycorrhizal fungi. The phylogenetic analysis assigned all thirteen ITS DNA barcoding Indian sequences of Astraeus to the Southeast Asian clade, reinforcing the genus Southeast Asian origin. Detailed species descriptions, line diagrams, SEM images of basidiospores, ITS nrDNA based phylogeny, and a dichotomous key are provided. Mycoobservations of the taxon from Pinus-Shorea subtropical and Shorea-dominated forests were additionally reviewed. [ABSTRACT FROM AUTHOR]

Promoting nature-based carbon sinks may contribute to minimise global warming. Different forest types may have different carbon sink capacity. Many areas of central Spain are covered by coexisting patches of monospecific plantations of Pinus halepensis, established since the 1960's, and native Quercus forest coppiced up to the 1960´s. We aimed to compare the carbon stock between both types of forests, considering both above and belowground compartments. In each plot, we measured the dimensions of every adult tree, the shrub cover, and we collected samples of litter and soil. The carbon pool of trees and shrubs was calculated using allometric equations, and for roots, litter, and soil, using the carbon content analysed in a laboratory or obtained from the literature. Carbon pools were analysed separately for three independent variables: plot type (Quercus/Pinus), tree basal area and slope. Overall, Quercus forests stored more carbon than Pinus plantations, thanks to a larger carbon stock in roots and shrubs in the former, which compensated for the larger aboveground carbon stock in tree biomass of Pinus plots. The carbon stock increased with basal area in all compartments except the soil. The carbon allocation pattern across compartments greatly varied between the two forest types, Pinus plots storing more than half (55%) of its carbon in the aboveground biomass of trees, while Quercus storing more carbon belowground (60%) in roots and soil. Given that belowground carbon stock is more resistant against disturbances, we conclude that native Quercus forests are more suitable for a long-term carbon storage. [ABSTRACT FROM AUTHOR]

The effect of an inoculum composed of Amanita stranella and Suillus decipiens was evaluated on morphological features and total phenolic compounds in seedlings of Pinus pseudostrobus var. coatepecensis – a narrow endemic Mexican variety. The treatments were used: (1) A. stranella; (2) S. decipiens; (3) combined inoculum and (4) control, using a completely randomized design with 12 seedlings per treatment. The morphotype descriptions of both fungi significantly facilitate their identification in the field. The results showed significant differences in plant growth among the treatment groups. Seedlings treated with the combined treatment exhibited remarkable increases in height, surpassing the A. stranella, S. decipiens treatments, and the control group by 21.81%, 28.83%, and 59%, respectively. Moreover, the root collar diameter in the combined treatment group measured 2.53 cm, contrasting with the control group, 1.05 cm. Additionally, the shoot height/root length ratio and Dickson's index were both close to 1 in the combined treatment, suggesting a well-developed root system in relation to the above-ground part of the plant. The percentage of ectomycorrhizal root colonization showed no significant differences among the inoculated treatments. Furthermore, the combined treatment significantly increased the total phenolic content in plants (39.2 mg GAE g− 1). Therefore, the combined inoculation of P. pseudostrobus var. coatepecensis seedlings with A. stranella and S. decipiens is recommended during the nursery stage for reforestation practices. [ABSTRACT FROM AUTHOR]

Species in the genus Picea are well-suited for afforestation on high altitudes and latitudes, but are fairly intolerant to high temperatures. In this study, Picea pungens, Picea abies, and Picea omorika were subjected to 45 °C, 40 °C, 35 °C, and ambient temperature (CK) for 6 h, and then allowed to recover for 28 d. Changes in phenotype, relative water content (RWC), and maximal photochemical efficiency (Fv/Fm) of photosystem II (PS II) were observed to ascertain their thermal tolerance. Overall, all three species were negatively affected by exposure to 45 °C, but P. pungens exhibited full recovery, with the highest RWC, while P. omorika exhibited partial recovery, and P. abies showed minimal recovery. The PS II of all three species were damaged after 45 °C treatment, but that of P. pungens exhibited the most dramatic recovery, with Fv/Fm recovering from 0 to 0.26. In conclusion, P. pungens was found to exhibit the greatest thermal tolerance, followed by P. omorika and P. abies. Thus, thermal tolerance should be considered as a tool for species selection for future reforestation endeavor in the face of climate change that is expected to bring high summer temperature events. [ABSTRACT FROM AUTHOR]

As a component of the biogeochemical cycle, litterfall contributes carbon and nutrients to forest ecosystems by transferring organic material to mineral soil. Litterfall therefore serves as an important indicator for soil fertility and ecosystem health. This study aimed to determine the impact of different levels of thinning (light, moderate, and heavy) on litterfall quantity (needles, branches, bark, cones, and miscellaneous parts) and on the amount of carbon and nutrients entering the ecosystem in black pine afforestation areas. Three levels of low thinning, namely light, moderate, and heavy thinning (15%, 25%, and 35% of breast height area, respectively), were applied as treatments. Additionally, a control plot was included in the experiment. Litterfall samples were collected four times per year (once per season) from 12 treatment plots for three years. In the laboratory, dry weight measurements and analyses of carbon and macro–micro nutrient elements (N, P, K, Ca, Mg, S, Na, Fe, Cu, Zn, and Mn) were performed on litterfall samples taken from the field. Differences between treatments in terms of litterfall and the amount of carbon and nutrient elements entering the ecosystem were evaluated through variance analysis and the Duncan test. According to the findings, the quantity of litterfall input into the forest floor was highest in the control treatment, at 6,543 kg ha−1 year−1 and lowest in the heavy treatment, at 4,378 kg ha−1 year−1, showing a significant variation in litterfall quantity. The input of C to the soil ranged between 2,233 kg ha−1 year−1 and 3,347 kg ha−1 year−1 depending on thinning treatment. Although thinning treatment reduced C input to the soil, there was no significant difference among treatments. This also applied to nutrient elements such as N, P, K, Mg, and S. Needles constituted the majority of litterfall components (60%) and had the highest C density among all components, at 51.2%. The weighted carbon ratio for litterfall was calculated at 50.8%. Considering carbon-focused planning, performing moderate thinning interventions in the study area or similar pine-afforested areas may be a suitable option for maintaining the sustainability and health of the forest. [ABSTRACT FROM AUTHOR]

The composition of the vascular flora in Punta Arenas city, found in the city's public spaces, was studied. The species were identified and recorded in a database, which was supplemented with information on taxonomic classification, growth habit, Raunkiaer's life form, origin status (native or exotic), and original continent-level distribution. These data were compared with studies conducted in five other cities in central Chile, together with an analysis of compositional similarity with these cities, by using the additive complement of Simpson's index (1– βsim). In Punta Arenas, 119 species were identified, showing a higher proportion of Gymnosperms compared to central Chilean cities. The most represented families were Asteraceae (16 species), Fabaceae (14), Rosaceae (14), Poaceae (12), and Pinaceae (10), which together accounted for 55% of the floristic richness. The compositional similarity between Punta Arenas and the other central Chilean cities ranged from 0.187 to 0.315, showing lower similarity than expected by chance (Montecarlo randomization test; P < 0.05). The primary origin distribution of Punta Arenas' vascular flora was European, unlike central Chilean cities where it was Asian. Finally, the proportion of exotic species (91.6%) and the number of exotic species per native species (16 exotics/native) were the highest documented for cities in Chile and higher than in other 114 cities worldwide. These results indicate that Punta Arenas' urban flora differs from the flora in central Chilean cities, not only in taxonomic composition but also in growth habit, biogeographical origin, and high level of exoticism. These differences are likely due to the city's territorial isolation and extreme southern location (53°S), leading to a unique urban flora configuration. [ABSTRACT FROM AUTHOR]

Inventorying forest ecosystems is an essential part of forest management planning. However, it is quite costly and time-consuming, particularly for larger areas. Recently, significant developments have been made in unmanned aerial vehicle (UAV) technology to improve the cost and time efficiency in forest inventory. Therefore, UAV images have become one of the inventory tools that produces data with high spatial resolution in determining forest resources. This study aims to investigate the contribution of UAV data to forest inventory in a case study area with a total of 30 sample plots located in pure and natural Crimean pine (Pinus nigra J.F. Arnold ssp. pallasiana (Lamb.) Holmboe) stands in the Black Sea backward region of Türkiye. Total tree height (h) and stem volume (v) were recorded at individual tree level (n = 367), and the number of trees (N), mean height (hmean), top height (htop), stand basal area (BA) and stand volume (V) were calculated at sample plot level (n = 30) from both the field and UAV-based data. Pearson's correlation coefficients (r) for h and v were 0.96 and 0.72, respectively, the highest correlation at the sample plot level was observed for the hmean - htop (r = 0.96), while the lowest correlation was found for BA (r = 0.54). The suitability of the observation and prediction values was assessed using a t-test at both individual tree and sample plot levels. According to the t-test results, the observation and prediction values for h, v, hmean, htop, BA and V metrics were found to be compatible (p > 0.05), but not for N (p < 0.05). Overall results indicated that UAV technology has a potential to be used in forest inventory and can contribute to the determination of individual tree and stand metrics. Thereby, it saves cost and time in forest inventory studies and helps monitoring the dynamic structure of the forest ecosystem with an effective approach in forest inventory. [ABSTRACT FROM AUTHOR]

Summary: Unlike 'white rot' (WR) wood‐decomposing fungi that remove lignin to access cellulosic sugars, 'brown rot' (BR) fungi selectively extract sugars and leave lignin behind. The relative frequency and distribution of these fungal types (decay modes) have not been thoroughly assessed at a global scale; thus, the fate of one‐third of Earth's aboveground carbon, wood lignin, remains unclear.Using c. 1.5 million fungal sporocarp and c. 30 million tree records from publicly accessible databases, we mapped and compared decay mode and tree type (conifer vs angiosperm) distributions. Additionally, we mined fungal record metadata to assess substrate specificity per decay mode.The global average for BR fungi proportion (BR/(BR + WR records)) was 13% and geographic variation was positively correlated (R2 = 0.45) with conifer trees proportion (conifer/(conifer + angiosperm records)). Most BR species (61%) were conifer, rather than angiosperm (22%), specialists. The reverse was true for WR (conifer: 19%; angiosperm: 62%). Global BR proportion patterns were predicted with greater accuracy using the relative distributions of individual tree species (R2 = 0.82), rather than tree type.Fungal decay mode distributions can be explained by tree type and, more importantly, tree species distributions, which our data suggest is due to strong substrate specificities. [ABSTRACT FROM AUTHOR]

In nature, plants have developed a series of resistance mechanisms to face various external stresses. As understanding of the molecular mechanisms underlying plant resistance continues to deepen, exploring endogenous resistance in plants has become a hot topic in this field. Despite the multitude of studies on plant-induced resistance, how plants respond to stress under natural conditions remains relatively unclear. To address this gap, we investigated Chinese pine (Pinus tabuliformis) using pine caterpillar (Dendrolimus tabulaeformis) under natural conditions. Healthy Chinese pine trees, approximately 10 years old, were selected for studying induced resistance in Huangtuliangzi Forestry, Pingquan City, Chengde City, Hebei Province, China. Pine needles were collected at 2 h and 8 h after feeding stimulation (FS) via 10 pine caterpillars and leaf clipping control (LCC), to simulate mechanical damage caused by insect chewing for the quantification of plant hormones and transcriptome and metabolome assays. The results show that the different modes of treatments significantly influence the contents of JA and SA in time following treatment. Three types of differentially accumulated metabolites (DAMs) were found to be involved in the initial response, namely phenolic acids, lipids, and flavonoids. Weighted gene co-expression network analysis indicated that 722 differentially expressed genes (DEGs) are positively related to feeding stimulation and the specific enriched pathways are plant hormone signal transduction and flavonoid biosynthesis, among others. Two TIFY transcription factors (PtTIFY54 and PtTIFY22) and a MYB transcription factor (PtMYB26) were found to be involved in the interaction between plant hormones, mainly in the context of JA signal transduction and flavonoid biosynthesis. The results of this study provide an insight into how JA activates, serving as a reference for understanding the molecular mechanisms of resistance formation in conifers responding to mandibulate insects. [ABSTRACT FROM AUTHOR]

Pinus yunnanensis is an important component of China's economic development and forest ecosystems. The growth of P. yunnanensis seedlings experienced a slow growth phase, which led to a long seedling cultivation period. However, asexual reproduction can ensure the stable inheritance of the superior traits of the mother tree and also shorten the breeding cycle. The quantity and quality of branching significantly impact the cutting reproduction of P. yunnanensis, and a shaded environment affects lateral branching growth, development, and photosynthesis. Nonetheless, the physiological characteristics and the level of the transcriptome that underlie the growth of lateral branches of P. yunnanensis under shade conditions are still unclear. In our experiment, we subjected annual P. yunnanensis seedlings to varying shade intensities (0%, 25%, 50%, 75%) and studied the effects of shading on growth, physiological and biochemical changes, and gene expression in branching. Results from this study show that shading reduces biomass production by inhibiting the branching ability of P. yunnanensis seedlings. Due to the regulatory and protective roles of osmotically active substances against environmental stress, the contents of soluble sugars, soluble proteins, photosynthetic pigments, and enzyme activities exhibit varying responses to different shading treatments. Under shading treatment, the contents of phytohormones were altered. Additionally, genes associated with phytohormone signaling and photosynthetic pathways exhibited differential expression. This study established a theoretical foundation for shading regulation of P. yunnanensis lateral branch growth and provides scientific evidence for the management of cutting orchards. [ABSTRACT FROM AUTHOR]

Summary: Evolutionary radiation, a pivotal aspect of macroevolution, offers valuable insights into evolutionary processes. The genus Pinus is the largest genus in conifers with c. 90% of the extant species emerged in the Miocene, which signifies a case of rapid diversification. Despite this remarkable history, our understanding of the mechanisms driving radiation within this expansive genus has remained limited.Using exome capture sequencing and a fossil‐calibrated phylogeny, we investigated the divergence history, niche diversification, and introgression among 13 closely related Eurasian species spanning climate zones from the tropics to the boreal Arctic.We detected complex introgression among lineages in subsection Pinus at all stages of the phylogeny. Despite this widespread gene exchange, each species maintained its genetic identity and showed clear niche differentiation. Demographic analysis unveiled distinct population histories among these species, which further influenced the nucleotide diversity and efficacy of purifying and positive selection in each species.Our findings suggest that radiation in the Eurasian pines was likely fueled by interspecific recombination and further reinforced by their adaptation to distinct environments. Our study highlights the constraints and opportunities for evolutionary change, and the expectations of future adaptation in response to environmental changes in different lineages. [ABSTRACT FROM AUTHOR]

The surface area of the leaves of trees that perform photosynthesis is expressed by the leaf area index (LAI) for pine trees with different densities, using direct methods by collecting field data in 2022 from (30) samples, and measurements were taken of the diameter at breast height for each sample and the total height, crown center height, crown width, and number of trees. Through field data and laboratory analysis of the relationships between the structure of tree elements, it was found that the leaf area index showed an inverse relationship with the distances between trees and that increasing the distance between trees reduces the crown coverage of trees and thus is reflected in the leaf area index of the tree. At low densities, it decreases and increases with increasing tree density. This also applies to the relationship between the dry weight of leaves and the distances between trees, as an inverse relationship showed, and this was also clear for the relationship between the dry weight of leaves and the average diameter and height of the trees in that tree. A set of equations was reached that was tested using multiple statistical standards, and it was the equation of the dry weight of pine tree leaves per unit area, the equation of the surface area of pine tree leaves per unit area, as well as the leaf area index of pine trees (LAI). [ABSTRACT FROM AUTHOR]

The genus Tarzetta is distributed mainly in temperate forests and establishes ectomycorrhizal associations with angiosperms and gymnosperms. Studies on this genus are scarce in México. A visual, morphological, and molecular (ITS-LSU) description of T. americupularis, T. cupressicola, T. davidii, T. durangensis, T. mesophila, T. mexicana, T. miquihuanensis, T. poblana, T. pseudobronca, T. texcocana, and T. victoriana was carried out in this work, associated with Abies, Quercus, and Pinus. The results of SEM showed an ornamented ascospores formation by Mexican Taxa; furthermore, the results showed that T. catinus and T. cupularis are only distributed in Europe and are not associated with any American host. [ABSTRACT FROM AUTHOR]

Ten new taxa of gymnosperms are added to the non-indigenous woody flora of Tunisia, after almost two decades of botanical surveys. Four of them (Cryptomeria japonica, Pinus brutia var. pityusa, Pseudotsuga menziesii var. glauca, Taxodium distichum var. distichum) are also new for the flora of North Africa. Pinus coulteri is here first reported for the Mediterranean Basin. Three genera (Cryptomeria, Pseudotsuga and Taxodium) are firstly recorded for the non-native vascular flora of Africa whereas two genera (Cedrus and Platycladus) are reported for the first time only for the woody flora of Tunisia. Brief descriptions together with filed photographs, global distributions and habitats at national scale are provided. Some taxonomic comments on their distinguishable features as well as updated keys are also presented. [ABSTRACT FROM AUTHOR]

The very early herbaceous vegetation which established in the clearings following 2018 'Vaia' storm was investigated in some pre-Alpine areas of Northeast Italy, on calcareous as well as acidic substrata. Sixty-two original vegetation-plot records were executed in spruce or mixed beech-silver fir-spruce blowdown forests, within two years after the salvage logging had been completed. According to different origin and degree of soil disturbance, different communities were recognised. Galeopsis pubescens and G. tetrahit rich stands develop as ephemeral annual associations at the beginning of the regeneration succession where partially decomposed coniferous needles and twigs have accumulated in the litter. Soils with altered profiles due to forestry machineries harbour dominance of perennial herbaceous species (especially Senecio nemorensis agg., Atropa bella-donna, Epilobium angustifolium) which origin as many already recognised associations or vegetation types we ascribed to community level. All coenoses belong to Epilobietea angustifolii class, with the exception of Calamagrostis arundinacea-rich stands on undisturbed base-rich as well as base-poor soils, whose syntaxonomic positions are unclear. [ABSTRACT FROM AUTHOR]

Nucleotide-binding domain and leucine-rich repeat (NLR) immune receptor genes form a major line of defense in plants, acting in both pathogen recognition and resistance machinery activation. NLRs are reported to form large gene clusters in limber pine (Pinus flexilis), but it is unknown how widespread this genomic architecture may be among the extant species of conifers (Pinophyta). We used comparative genomic analyses to assess patterns in the abundance, diversity, and genomic distribution of NLR genes. Chromosome-level whole genome assemblies and high-density linkage maps in the Pinaceae, Cupressaceae, Taxaceae, and other gymnosperms were scanned for NLR genes using existing and customized pipelines. The discovered genes were mapped across chromosomes and linkage groups and analyzed phylogenetically for evolutionary history. Conifer genomes are characterized by dense clusters of NLR genes, highly localized on one chromosome. These clusters are rich in TNL-encoding genes, which seem to have formed through multiple tandem duplication events. In contrast to angiosperms and nonconiferous gymnosperms, genomic clustering of NLR genes is ubiquitous in conifers. NLR-dense genomic regions are likely to influence a large part of the plant's resistance, informing our understanding of adaptation to biotic stress and the development of genetic resources through breeding. [ABSTRACT FROM AUTHOR]

It can provide a basis for decision making for the conservation and sustainable use of forest ecosystems in mountains to understand the stoichiometric properties and nutrient allocation strategies of major tree species. However, the plant nutrient allocation strategies under different environmental gradients in forest systems of arid and semi-arid mountains are not fully understand. Therefore, three typical regions in the Qilian Mountains on the eastern edge of the Qinghai-Tibet Plateau were selected based on precipitation and temperature gradients, and the stoichiometric characteristics and nutrient allocation strategies of Qinghai spruce (Picea crassifolia) of the dominant tree species under different environmental gradients were investigated. The results showed that (1) the stoichiometric characteristics of plant tissues were different in the three regions. (2) The importance of each tissue in the plant nutrient allocation varied in different regions, showing that the plant roots are more important in the warm-wet region, while the plant leaves, branches and trunks are more important in the transition and hot-dry regions. (3) The influencing factors affecting plant nutrient allocation strategies were inconsistent across regions, which showed that plant nutrient allocation strategies in the warm-wet and transition region were mainly influenced by soil factors, while they were more influenced by climatic factors in the hot-dry region. The patterns of plant nutrient allocation strategies and drivers under different environmental gradients could help us better understand the ecological adaptation mechanism and physiological adjustment mechanism of forest ecosystem in mountains. [ABSTRACT FROM AUTHOR]

Picea jezoensis (Siebold & Zucc.) Carrière forests are distributed in Korea and China and are crucial for phytogeographical research. Implementing conservation policies encompassing multiple species is necessary to conserve endangered species, particularly monitoring coexisting species and their interactions within an ecological network. Here, we identified plants within P. jezoensis forests in East Asia as generalist species to contribute foundational data for biodiversity conservation. We examined 91 standardized sites through the Braun-Blanquet method, while generalist indices were calculated using Levin's method. The top 5% of generalists in the P. jezoensis forests were Acer komarovii (0.7409), Betula ermanii (0.7214), Asarum sieboldii (0.7002), Lepisorus ussuriensis (0.6977), Acer pseudosieboldianum (0.6915), Tripterygium regelii (0.6876), Thelypteris phegopteris (0.6771), Dryopteris expansa (0.6745), Sorbus commixta (0.6642), and Rhododendron schlippenbachii (0.6625). Correlation analysis between ecological factors and generalist species revealed that the coverage of Abies spp., Acer spp., and Rhododendron spp. and the species diversity index were influenced by altitude. Convex hull analysis revealed that pteridophytes and broad-leaved plants regenerated through stump sprouts occupy ecological niche spaces, indicating diverse habitats within P. jezoensis forests. This study highlights the importance of the simultaneous monitoring of multiple species to conserve ecosystem health and offers broader implications for ecological understanding. [ABSTRACT FROM AUTHOR]

Background and Aims Secondary cell wall (SCW) thickening is a major cellular developmental stage determining wood structure and properties. Although the molecular regulation of cell wall deposition during tracheary element differentiation has been well established in primary growth systems, less is known about the gene regulatory processes involved in the multi-layered SCW thickening of mature trees. Methods Using third-generation [long-read single-molecule real-time (SMRT)] and second-generation [short-read sequencing by synthesis (SBS)] sequencing methods, we established a Pinus bungeana transcriptome resource with comprehensive functional and structural annotation for the first time. Using these approaches, we generated high spatial resolution datasets for the vascular cambium, xylem expansion regions, early SCW thickening, late SCW thickening and mature xylem tissues of 71-year-old Pinus bungeana trees. Key Results A total of 79 390 non-redundant transcripts, 31 808 long non-coding RNAs and 5147 transcription factors were annotated and quantified in different xylem tissues at all growth and differentiation stages. Furthermore, using this high spatial resolution dataset, we established a comprehensive transcriptomic profile and found that members of the NAC, WRKY, SUS, CESA and LAC gene families are major players in early SCW formation in tracheids, whereas members of the MYB and LBD transcription factor families are highly expressed during late SCW thickening. Conclusions Our results provide new molecular insights into the regulation of multi-layered SCW thickening in conifers. The high spatial resolution datasets provided can serve as important gene resources for improving softwoods. [ABSTRACT FROM AUTHOR]

Macrolichen diversity and community composition were determined for an area of high botanical interest in the Coast Ranges of Northern California – the Horse Mountain Botanical Area (HMBA) in Six Rivers National Forest. The Coast Ranges have been suggested to have high lichen diversity, yet detailed site-specific macrolichen surveys are lacking for the area. The HMBA is characterized by the presence of ultramafic (serpentine) soils, contributing to its diverse assemblage of conifers. Here we present comprehensive data on macrolichens of the HMBA integrated with environmental variables at the landscape level. Twenty 0.4 ha sampling plots were positioned across the varying habitats of the HMBA and macrolichens were intensively sampled from all substrata. Out of 888 total collections, 119 macrolichen species in 52 genera were identified, 63 species were sequenced for the mycobiont internal transcribed spacer (ITS) region, and all species were vouchered. Microenvironmental influences on lichen community composition were ordinated with nonmetric multidimensional scaling (NMS). Within-plot measured environmental variables with strongest correlations to ordination Axis 1 were 1) total tree basal area, 2) proportion of conifer basal area relative to hardwoods, and 3) distance between plot center and nearest stream. Distinct macrolichen communities were found in plots containing primarily conifers versus mixed hardwood-conifer plots. All plots contained both nitrogen-fixing and pendulous forage macrolichens; in each of the three hardwood-dominated plots, nitrogen-fixing lichens composed nearly a third of the species total. When epiphytic macrolichen species richness and dominance within the HMBA were compared to data from other regional forests, the HMBA showed comparable community composition but averaged 39% higher species richness. Results from this study can help inform management of the HMBA as well as future taxonomic and ecological research on regional macrolichens. [ABSTRACT FROM AUTHOR]

The modern typological structure of vegetation inhabiting the southern Kuril Islands has been identified on the basis of computed Bravais correlation coefficients. This structure is represented by eight pleiades: fir forests with Abies sachalinensis; spruce forests with Picea ajanensis; Sasa senanensis thickets (Shikotan Island); elm–maple forests with Acer ukurunduense and Acer mayrii (Kunashir Island); maple–oak forests with Acer mayrii and Quercus crispula (Iturup Island); Juniperus sargentii thickets (Shikotan Island) and communities with Pinus pumila (Iturup and Kunashir Islands); and alder–birch phytocoenoses, reed–tall-grass and coastal meadows, and ruderal vegetation. The species diversity of plants is determined by local species of East Asian origin. The amphipacific group manifested along the coastline demonstrates the affinity of local species and the North American flora. The proportion of foreign species increases on disturbed sites. Indigenous phytocoenoses are represented by fir and spruce forests, as well as Pinus pumila and Juniperussargentii thickets in the mountains and on the rocks. Under the impact of unfavorable factors, indigenous groups are replaced by birch forests with Betula ermanii and secondary meadows, including ruderal–forb–gramineous coenoses; felling and fire sites are overgrowing with bamboo thickets with Sasa senanensis. Preliminary estimates indicate that the share of disturbed lands on Shikotan reaches 40%, including 30% disturbed by anthropogenic impacts and 10% due to natural factors. On Kunashir, proportions of these lands amount to 16 and 17%, respectively, and, on Iturup, 23 and 16%. It is shown that Sasa senanensis thickets, despite their secondary nature, play a key role in preventing the further degradation of natural complexes, soil erosion, and exogenous geological processes. [ABSTRACT FROM AUTHOR]

Pinus occidentalis (Swartz) is the primary timber species in the Dominican Republic (DR). Despite its economic importance, studies conducted on this species are scarce, making it difficult to estimate current inventory levels. This study aims to enhance the accuracy of estimating the total bole volume of P. occidentalis in different ecological zones (EZs) within La Sierra, evaluating and comparing two established volume equations—combined variable (CV) and Schumacher and Hall (S&H) across nine modeling variants. An indicator variables analysis determined the necessity of distinct equations for two EZs. Fitting included both linear and nonlinear models. Our comprehensive statistical analysis included goodness-of-fit metrics to evaluate each model variant's performance rigorously. The second modeling variant (SH02) for the SH equation was most effective in the Dry Ecological Zone, showing superior performance in both the fitting and validation phases. Similarly, the third modeling variant (SH03) for the SH equation emerged as the best fit for the Combined Intermediate and Humid Ecological Zones, achieving the lowest overall ranking sum among tested variants. SH02 and SH03 provide reliable and precise volume estimations, allowing for the optimization of forestry management practices for P. occidentalis trees. The SH models outperformed the CV model variants' consistency in parameter estimation. This tailored approach ensures more accurate volume predictions, which is crucial for sustainable management and conservation efforts. [ABSTRACT FROM AUTHOR]

In Pinus massoniana, the methyl-D-erythritol-4-phosphate (MEP) pathway plays a crucial role in the biosynthesis of terpenoids. The fourth step of this pathway is specifically regulated by 4-(cytidine 5′-diphospho)-2-C-methyl-D-erythritol kinase (CMK). In this study, PmCMK (MW892445.1) was isolated. As a member of the GHMP kinase family, PmCMK exhibits homology with CMK genes across diverse species. The examination of relative expression patterns revealed that PmCMK exhibited higher expression levels in tissues of P. massoniana that are rich in resin. We successfully cloned the PmCMK promoter (1654 bp) and integrated it into a GUS reporter vector. This construct was then transformed into the leaves of tobacco (Nicotiana × sanderae) to assess transient expression patterns. The results demonstrated that the promoter was active not only in the roots, leaves, and stems of the tobacco plants but also exhibited varying expression levels in response to treatments with IAA, SA, MeJA, and PEG6000. This suggested that PmCMK expression was modulated by a variety of signals. It revealed that the expression of PmCMK was affected by different treatments. Further allogeneic expression studies showed that tobacco overexpressing PmCMK exhibited increased levels of chlorophyll and carotene compared to the wild type. This enhancement in content indicates that PmCMK has a significant role in isoprene biosynthesis. These findings provide valuable insights for future research aimed at elucidating the biosynthetic pathways of terpenoids and developing breeding strategies to enhance resin production in P. massoniana. [ABSTRACT FROM AUTHOR]

Dahurian larch (Larix gmelinii) is the dominant tree species in boreal forests, and its photosynthetic response to climate warming is important in modeling and predicting carbon cycling for boreal forest ecosystems. In 1983, seedlings of L. gmelinii from 11 provenances were transplanted into two common gardens with different climate conditions (control and warming climate). Forty years after the transplant, we investigated the response of leaf photosynthetic capacity to climate warming and its variation among provenances. The warming treatment significantly increased the maximum net photosynthetic rate (Pmax-a), photosynthetic nitrogen use efficiency (PNUE), maximum carboxylation rate (Vcmax), maximum electron transport rate (Jmax), triose phosphate utilization rate (TPU), mesophyll conductance (gm), leaf nitrogen content (Narea), and chlorophyll content (Chlm). Pmax-a was significantly positively associated with Vcmax, Jmax, TPU, gm, and Narea, and the slope of the linear regression between Pmax-a and Vcmax, Jmax, and TPU was greater in the warming treatment. The responses of Pmax-a, PNUE, Vcmax, Jmax, TPU, Narea, and Chlm to warming differed among provenances. As the aridity index of the original site increased, the magnitude of the warming treatment's effect on Pmax-a, Vcmax, Jmax, and TPU represented a varying form of a bell-shaped curve. Overall, the warming treatment improved the photosynthetic capacity of L. gmelinii, but the extent of the improvement varied among provenances. These findings provide insights into the mechanisms underlying the responses of L. gmelinii to climate warming. [ABSTRACT FROM AUTHOR]

Natural vegetation protects, maintains, and improves the environment through its ecological functions and is, thus, an important component of Earth's ecosystems. The distribution of natural vegetation and its corresponding ecological roles vary with the topographic gradient. Understanding this role is essential for effective ecosystem management and conservation efforts. This study analyzes vegetation composition across altitude gradients and the spatiotemporal evolution of water conservation, soil conservation, and carbon storage in the southern hill and mountain belt of China. We then explored the drivers of the ecological functions of vegetation at different altitude gradients. The results showed that water conservation increased by 108.56%, soil conservation increased by 97.04%, and carbon storage increased only slightly. The ecological functions of vegetation varied across altitude gradients, with the 500–800 m gradient exhibiting markedly higher ecological functions than the other gradients. The effect of precipitation on soil conservation increases with altitude. In addition, at higher altitudes, evergreen coniferous forests had a greater effect on carbon storage. Based on the results, we propose vegetation management measures for different altitudes. This study provides a reference for decision-makers to develop and adjust ecological restoration programs in mountainous areas for the improvement of the local ecological environment. [ABSTRACT FROM AUTHOR]