Precious Tree Research Articles

The Spatial Shifts and Vulnerability Assessment of Ecological Niches under Climate Change Scenarios for Betula luminifera, a Fast-Growing Precious Tree in China.

The spatial shifts and vulnerability assessments of ecological niches for trees will offer fresh perspectives for sustainable development and preservation of forests, particularly within the framework of rapid climate change. Betula luminifera is a fast-growing native timber plantation species in China, but the natural resources have been severely damaged. Here, a comprehensive habitat suitability model (including ten niche-based GIS modeling algorithms) was developed that integrates three types of environmental factors, namely, climatic, soil, and ultraviolet variables, to assess the species contemporary and future distribution of suitable habitats across China. Our results suggest that the habitats of B. luminifera generally occur in subtropical areas (about 1.52 × 106 km2). However, the growth of B. luminifera is profoundly shaped by the nuances of its local environment, the most reasonable niche spaces are only 1.15 × 106 km2 when limiting ecological factors (soil and ultraviolet) are considered, generally considered as the core production region. Furthermore, it is anticipated that species-suitable habitats will decrease by 10 and 8% with climate change in the 2050s and 2070s, respectively. Our study provided a clear understanding of species-suitable habitat distribution and identified the reasons why other niche spaces are unsuitable in the future, which can warn against artificial cultivation and conservation planning.

The Phylogeography of Deciduous Tree Ulmus macrocarpa (Ulmaceae) in Northern China

Disentangling how climate oscillations and geographical events significantly influence plants’ genetic architecture and demographic history is a central topic in phytogeography. The deciduous ancient tree species Ulmus macrocarpa is primarily distributed throughout Northern China and has timber and horticultural value. In the current study, we studied the phylogenic architecture and demographical history of U. macrocarpa using chloroplast DNA with ecological niche modeling. The results indicated that the populations’ genetic differentiation coefficient (NST) value was significantly greater than the haplotype frequency (GST) (p < 0.05), suggesting that U. macrocarpa had a clear phylogeographical structure. Phylogenetic inference showed that the putative chloroplast haplotypes could be divided into three groups, in which the group Ⅰ was considered to be ancestral. Despite significant genetic differentiation among these groups, gene flow was detected. The common ancestor of all haplotypes was inferred to originate in the middle–late Miocene, followed by the haplotype overwhelming diversification that occurred in the Quaternary. Combined with demography pattern and ecological niche modeling, we speculated that the surrounding areas of Shanxi and Inner Mongolia were potential refugia for U. macrocarpa during the glacial period in Northern China. Our results illuminated the demography pattern of U. macrocarpa and provided clues and references for further population genetics investigations of precious tree species distributed in Northern China.

Enhancing flame retardancy and antibacterial properties of wood veneer by promoting crosslinking in metal-organic framework structures

Decorative veneer, rotary cut from wood, serving as the outermost layer of decorative plates and is exposed to potential risks of fire hazards and bacterial growth. In this study, following the principle of eco-friendly and cost-effective, the polyamino polyether methylene phosphonate (PAPEMP) and magnesium chloride (MgCl2) were sequentially impregnated into the veneer, and then the alkaline environment was employed to facilitate the complexation, leading to the formation of cross-linked chains within the porous wood structure. Consequently, the modified wood veneer, endowed with exceptional flame retardancy, smoke suppression, antibacterial properties, and good wettability was successfully achieved. Through optimization in an alkaline environment, the modified decorative veneer exhibits a remarkable increase in limiting oxygen index from 19.7% in the pure veneer to 36.9%, coupled with a significant reduction of 19.38% in total heat release and 65.22% in total smoke release compared to the pure veneer. Additionally, the peak mass loss rate (PLMR) of the modified veneer was 66.41% lower than that of the pure veneer, and the char residue increased to 46.1%, representing a 149.19% improvement over the pure veneer. Compared with pure veneer, the wettability of modified veneer increased by 37.93%. Additionally, the tensile strength parallel to the grain of the modified veneer was enhanced by 22.09% compared to the veneer without NaOH solution treatment, and exhibits strong inhibitory effects on colony reproduction. The developed flame-retardant and antibacterial treatment processes for decorative veneers offer a novel and environmentally friendly method for utilizing precious tree veneers, suitable for a variety of precious woods, and successfully applied to decorative wooden doors and wooden fire-resistant doors.

Advances in Eucommia ulmoides polysaccharides: extraction, purification, structure, bioactivities and applications.

Eucommia ulmoides (EU) is a precious tree species native to China originating during the ice age. This species has important economic value and comprehensive development potential, particularly in medicinal applications. The medicinal parts of EU are its bark (Eucommiae cortex) and leaves (Eucommiae folium) which have been successively used as a traditional Chinese medicine to treat diseases since the first century BC. During the last 2decades, as natural polysaccharides have become of increasing interest in pharmacology, biomedicine, cosmetic and food applications, more and more scholars have begun to study polysaccharides derived from EU as well. EU polysaccharides have been found to have a variety of biological functions both in vivo and in vitro, including immunomodulatory, antioxidant, anti-inflammatory, anticomplementary, antifatigue, and hepatoprotective activities. This review aims to summarize these recent advances in extraction, purification, structural characteristics, pharmacological activities and applications in different fields of EU bark and leaf polysaccharides. It was found that both Eucommiae folium polysaccharides and Eucommiae cortex polysaccharides were suitable for medicinal use. Eucommiae folium may potentially be used to substitute for Eucommiae cortex in terms of immunomodulation and antioxidant activities. This study serves as a valuable reference for improving the comprehensive utilization of EU polysaccharides and further promoting the application of EU polysaccharides.

The DNA barcode identification of Dalbergia odorifera T. Chen and Dalbergia tonkinensis Prain

BackgroundDalbergia odorifera is a precious tree species with unique economic and medicinal values, which is difficult to distinguish from Dalbergia tonkinensis by traditional identification methods such as morphological characteristics and wood structure characteristics. It has been demonstrated that the identification of tree species can be effectively achieved using DNA barcoding, but there is a lack of study of the combined sequences used as DNA barcodes in the two tree species. In this study, 10 single sequences and 4 combined sequences were selected for analysis, and the identification effect of each sequence was evaluated by the distance-based method, BLAST-based search, character-based method, and tree-based method.ResultsAmong the single sequences and the combined sequences, the interspecies distance of trnH-psbA and ITS2 + trnH-psbA was greater than the intraspecies distance, and there was no overlap in their frequency distribution plots. The results of the Wilcoxon signed-rank test for the interspecies distance of each sequence showed that the interspecies differences of the single sequences except trnL-trnF, trnH-psbA, and ycf3 were significantly smaller than those of the combined sequences. The results of BLAST analysis showed that trnH-psbA could accurately identify D. odorifera and D. tonkinensis at the species level. In the character-based method, single sequences of trnL-trnF, trnH-psbA with all the combined sequences can be used for the identification of D. odorifera and D. tonkinensis. In addition, the neighbor-joining (NJ) trees constructed based on trnH-psbA and ITS2 + trnH-psbA were able to cluster D. odorifera and D. tonkinensis on two clades.ConclusionsThe results showed that the character-based method with the BLOG algorithm was the most effective among all the evaluation methods, and the combined sequences can improve the ability to identify tree species compared with single sequences. Finally, the trnH-psbA and ITS2 + trnH-psbA were proposed as DNA barcodes to identify D. odorifera and D. tonkinensis.

Morphological and Anatomical Characteristics of Taxus chinensis (Pilg.) Rehder in Thanh Hoa Province, Vietnam

The Taxus chinensis (Pilg.) Rehder belongs to the Taxaceae family, confer plants and is a rare and precious tree species of Vietnam which was recognized for its use value. The most of them are distributed in the high mountains of Vietnam. The resource values of this species were found as medicine, precious wood and an ornamental. So, looking back to the long history of use as well as overall research on species of the Taxus L. genus, the up-to-date reporting on Taxus chinensis is relatively much less extensive. These studies are an effort to understand the anatomical delimitation of Taxus chinensis (Pilg.) Rehder in a better way and morphological characteristic with updated is provided. The comparative morphological and anatomical research method were used, Taxus chinensis has dominent characteristic with winter bud scales, gather into a cone shape, early deciduous; leaves linear, thick textured; pale to white at abaxially because of the thick stomata bands.

A Machine Learning Based Framework for a Stage-Wise Classification of Date Palm White Scale Disease

Date palm production is critical to oasis agriculture, owing to its economic importance and nutritional advantages. Numerous diseases endanger this precious tree, putting a strain on the economy and environment. White scale Parlatoria blanchardi is a damaging bug that degrades the quality of dates. When an infestation reaches a specific degree, it might result in the tree's death. To counter this threat, precise detection of infected leaves and its infestation degree is important to decide if chemical treatment is necessary. This decision is crucial for farmers who wish to minimize yield losses while preserving production quality. For this purpose, we propose a feature extraction and machine learning (ML) technique based framework for classifying the stages of infestation by white scale disease (WSD) in date palm trees by investigating their leaflets images. 80 gray level co-occurrence matrix (GLCM) texture features and 9 hue, saturation, and value (HSV) color moments features are extracted from both grayscale and color images of the used dataset. To classify the WSD into its four classes (healthy, low infestation degree, medium infestation degree, and high infestation degree), two types of ML algorithms were tested; classical machine learning methods, namely, support vector machine (SVM) and k-nearest neighbors (KNN), and ensemble learning methods such as random forest (RF) and light gradient boosting machine (LightGBM). The ML models were trained and evaluated using two datasets: the first is composed of the extracted GLCM features only, and the second combines GLCM and HSV descriptors. The results indicate that SVM classifier outperformed on combined GLCM and HSV features with an accuracy of 98.29%. The proposed framework could be beneficial to the oasis agricultural community in terms of early detection of date palm white scale disease (DPWSD) and assisting in the adoption of preventive measures to protect both date palm trees and crop yield.

Multispectral Image Determination of Water Content in Aquilaria sinensis Based on Machine Learning

The real-time nondestructive monitoring of plant water content can enable operators to understand the water demands of crops in a timely manner and provide a reliable basis for precise irrigation. In this study, a method for rapid estimation of water content in Aquilaria sinensis using multispectral imaging was proposed. First, image registration and segmentation were performed using the Fourier–Mellin transform (FFT) and the fuzzy local information c-means clustering algorithm (FLICM). Second, the spectral features (SFs), texture features (TFs), and comprehensive features (CFs) of the image were extracted. Third, using the eigenvectors of the SFs, TFs, and CFs as input, a random forest regression model for estimating the water content of A. sinensis was constructed, respectively. Finally, the monarch butterfly optimization (MBO), Harris hawks optimization (HHO), and sparrow search algorithm (SSA) were used to optimize all models to determine the best estimation model. The results showed that: (1) 60%–80% soil water content is the most suitable for A. sinensis growth. Compared with waterlogging, drought inhibited A. sinensis growth more significantly. (2) FMT + FLICM could achieve rapid segmentation of discrete A. sinensis multispectral images on the basis of guaranteed accuracy. (3) The prediction effect of TFs was basically the same as that of SFs, and the prediction effect of CFs was higher than that of SFs and TFs, but this difference would decrease with the optimization of the RFR model. (4) Among all models, SSA-RFR_CFs had the highest accuracy, with an R2 of 0.8282. These results confirmed the feasibility and accuracy of applying multispectral imaging technology to estimate the water content of A. sinensis and provide a reference for the protection and cultivation of endangered precious tree species.

Santulum album: Medicinal and Pharmacological Properties

Medicinal plants are used since the dawn of human civilization for therapeutic purpose. New bioactive natural compounds came into existence due to the extensive use of herbal remedies and therapeutic preparations obtained from medicinal plants. In the review attempt has been made to collect the data on the medicinal and pharmacological properties of Santalum album. Data has been collected using different search engines (google scholar, Pubmed, Elsevier, Springer link, science direct), books, Literature reviews. Santalum album is commercially important plant belong to Santalaceae family. Santulum album commonly known as sandal wood is well known all over the world for its most expensive stem. It has many therapeutic efficacy and used in different ailments. It is Disinfectant in genitourinary and bronchial tracts, diuretic, expectorant and stimulant. Sandalwood is the precious tree cultured in India. S. album is mainly grown for its timber and fragrant oil. Like rosewood and cinnamon wood, it is also an aromatic wood. The powder of wood is used medicinal, culture and religious purpose. Therefor it is used to make perfumes, in cosmetic industry, in pharmaceutical industries and aromatherapy. In pharmacology sandalwood acts as coolant, sedative, astringent. In the present review we discuss the medicinal and pharmacological potential of Santalum album.

Effects of Ascorbic Acid on Physiological Characteristics during Somatic Embryogenesis of Fraxinus mandshurica

Fraxinus mandshurica is one of the precious tree species in northeast China and has important economic and ecological value. Ascorbic acid (ASA) is a strong antioxidant that can significantly improve plant photosynthetic efficiency and stress resistance and participate widely in plant growth and development. In this study, we investigated the development process of mature zygotic embryos of F. mandshurica under different concentrations of ASA and found that 100 mg·L-1 exogenous ASA was the optimal concentration and that the induction rate of somatic embryos (SEs) was the highest at 72.89%, which was 7.13 times higher than that of the control group. The polyphenol content, peroxidase (POD) activity, nitric oxide (NO) content, nitrate reductase (NR) activity, total ascorbic acid (T-ASA) content, ASA content, ASA/Dehydroascorbic acid (DHA) ratio, GSH/GSSG ratio, and ascorbate peroxidase (APX) activity were significantly increased under the application of exogenous ASA in explants, whereas the polyphenol oxidase (PPO) activity, phenylalanine ammonia-lyase (PAL) activity, superoxide dismutase (SOD) activity, and catalase (CAT) activity, malondialdehyde (MDA) content and nitric oxide synthase (NOS) activity were decreased. At the same time, the content of T-ASA and ASA, T-GSH and GSSG, and PAL and SOD had the same change pattern in the control group and the treatment group. These results suggested that high or low concentrations of ASA could not promote the somatic embryogenesis of F. mandshurica and that exogenous ASA had significant effects on the physiology of F. mandshurica explants. ASA was also highly related to somatic embryogenesis and the explant browning of F. mandshurica. Our results could provide a reference for further study on the browning mechanism of F. mandshurica explants and lay the foundation for optimizing the condition of somatic embryogenesis in F. mandshurica.

Growth performance of Santalum album L. in Association with different Host species in South Gujarat Region

Santalum album is conceived as one of the most precious tree species in the world. In the present investigation growth performance of sandalwood with reference to various host species has been studied on five years old plantation in moist deciduous region of southern Gujarat. Three parameters height, DBH and volume index were considered for comparing growth performance of sandalwood in association with eight host species in four replications and ten combinations for a total of 240 plants. Significant variations among all combination were statistically analyzed through oneway ANOVA test. Cajanus cajan and Cassia siamea showed most potential host species for sandalwood growth compared to other host species.

Precious Tree Pest Identification with Improved Instance Segmentation Model in Real Complex Natural Environments

It is crucial to accurately identify precious tree pests in a real, complex natural environment in order to monitor the growth of precious trees and provide growers with the information they need to make effective decisions. However, pest identification in real complex natural environments is confronted with several obstacles, including a lack of contrast between the pests and the background, the overlapping and occlusion of leaves, numerous variations in pest size and complexity, and a great deal of image noise. The purpose of the study was to construct a segmentation method for identifying precious tree pests in a complex natural environment. The backbone of an existing Mask region-based convolutional neural network was replaced with a Swin Transformer to improve its feature extraction capability. The experimental findings demonstrated that the suggested method successfully segmented pests in a variety of situations, including shaded, overlapped, and foliage- and branch-obscured pests. The proposed method outperformed the two competing methods, indicating that it is capable of accurately segmenting pests in a complex natural environment and provides a solution for achieving accurate segmentation of precious tree pests and long-term automatic growth monitoring.

Effects of Precious Tree Introduction into Moso Bamboo Forests on Soil Carbon and Nitrogen Pools

Forest type conversion is an important factor affecting soil carbon (C) and nitrogen (N) pools. Planting precious trees in moso bamboo forest is an important measure taken to establish a mixed forest due to the vulnerable ecological functioning of moso bamboo forest. However, the ways in which soil C and N pools in moso bamboo forest are affected by precious tree introduction are still unclear. A pure moso bamboo forest (BF), a bamboo forest interplanted with Phoebe chekiangensis (BPC), and a bamboo forest interplanted with Taxus wallichiana var. mairei (BTW) were selected. Soil organic C (SOC), total N, microbial biomass C (MBC), microbial biomass N (MBN), water-soluble organic C (WSOC), water-soluble organic N (WSON), and litter C and N concentrations were determined. Our results showed that the concentrations of SOC and N in BF were significantly lower than those in BPC and BTW. The total SOC and N concentrations decreased with increasing soil depth, and they were significantly higher at 0–20 cm than those at 20–40 cm and 40–60 cm. The biomasses of litters and their concentrations of C and N were increased after planting precious trees in moso bamboo forest, and they were significantly lower in BF than in BPC and BTW. In addition, precious tree introduction also improved the concentrations of soil MBC, MBN, WSOC, and WSON. To conclude, planting precious trees in moso bamboo forest significantly increased SOC and N concentrations at soil depths of 0–60 cm.

De novo transcriptome assembly and development of EST-SSR markers for Pterocarpus santalinus L. f. (Red sanders), a threatened and endemic tree of India

The endemic and precious tree Pterocarpus santalinus L. f. (Red sanders) is a drought hardy species for conservation in peninsular India due to its high risk of illegal timber harvest. It is only found in Eastern Ghats of India, and has become threatened owing to overexploitation of its valuable timber. The development of genomic resources, particularly simple sequence repeat (SSR) markers, is essential for strict implementation of in situ conservation measures and application of DNA information based red sanders genetic resource management. However, a lack of genomic data and efficient molecular markers limit the study of its spatial and temporal population genetic structure, identification of diversity hotspots and tree improvement. The current study aims at comprehensive molecular characterization of red sanders and the somatic chromosome counts, flow cytometry and EST-SSR analyses. The results revealed that red sanders is diploid with 2n = 20 and the 2C genome size was 0.7872 ± 0.0561 pg for the first time in this species. A total of 3128 EST-SSRs were detected based on 25,854 de novo assembled unigenes from transcriptome data and primer sets designed for 1953 SSRs. Fifty-nine EST-SSR markers were evaluated for polymorphism in the natural populations of red sanders and 13 were found to be suitable for genetic analysis. Two major transcription factor families bHLH and ERF, responsible for abiotic stress and secondary metabolite synthesis were analysed which would provide the foundation for further research on production of medicinally important biocompounds.

Complete chloroplast genome of Toona ciliata Roem. var. pubescens (Franch.) Hand.-Mazz (Meliaceae), ‘Chinese mahogany’

Toona ciliata var. pubescens is classified as Toona subgenus of Meliaceae family, which belongs to a large deciduous tree species. It is also a kind of precious timber tree species and has a certain medicinal value. Here, the first complete chloroplast genome (cpDNA) sequence of T. ciliata var. pubescens was determined using the Illumina sequencing platform. The cpDNA genome is 159,481 bp in length, containing a large single-copy region (LSC) of 87,176 bp and a small single-copy region (SSC) of 18,381 bp, which were separated by a pair of inverted repeats (IRs) regions of 26,962 bp. The genome contains 138 genes, including 90 protein-coding genes, eight ribosomal RNA genes, and 40 transfer RNA genes. The phylogenetic analysis based on 19 cpDNA genomes showed a close relationship with Toona ciliate.

The complete chloroplast genome of the aromatic tree species Cinnamomum tenuipile Kosterm (Lauraceae)

Cinnamomum tenuipile Kosterm is a precious aromatic tree in Lauraceae. To better determine its phylogenetic location with other Cinnamomum species, the chloroplast genome of C. tenuipile was sequenced. The complete chloroplast genome size is 152,761 bp, consisting of a pair of inverted repeats (IRa/b) with a length of 20,074 bp separated by a large single-copy region (LSC) and a small single-copy region (SSC) which are 93,685 and 18,928 bp, respectively. The overall GC content of the cp genome is 39.16%. The maximum-likelihood phylogenetic tree showed that C. tenuipile is more closely related to C. aromaticum, providing new insight into the evolution of Lauraceae.

“All the Precious Trees of the Earth”: Trees in Restoration Scripture

In Hebrew scripture and the New Testament, trees play a prominent role, most obviously in the first chapters of Genesis and the last chapter of Revelations. Trees also serve as messianic heralds, as life-giving resources, as aesthetic standards of beauty, as exemplars of strength and fame, and as markers and instruments of salvation. Like the Hebrew Bible, the Book of Mormon and other Latter-day Saint scriptures feature prominent references to forests, trees, branches, roots, and seeds. What is unique about the spiritual and cultural landscape invoked by Latter-day Saint scripture? More specifically, what is said about trees and their accoutrements in restoration scripture? While numerous studies have focused on the major thematic tree scenes in the Book of Mormon, the tree of life in the visions of Lehi and Nephi, Zenos’ allegory of the olive tree, and Alma’s discourse on the seed of faith and the tree of righteousness, this paper aims at a broader look at trees in Latter-day Saint scripture. Taking cues from Robert Pogue Harrison’s Forests: The Shadow of Civilization, this paper takes a wide-ranging look at how trees in restoration scripture can help us rhetorically address the ecological dilemmas of our time. When the Gods built us a home, they did so with trees, and when God called on Their people to build a house, God told them to “bring the box tree, and the fir tree, and the pine tree, together with all the precious trees of the earth” to build it (see Abraham 4:11–12 and D&C 124:26–27). Another revelation declares bluntly: “Hurt not the earth, neither the sea, nor the trees” (D&C 77:9). As eaters of sunshine and exhalers of oxygen, trees have much to teach us about how to live, and trees in restoration scripture specifically contribute to a broader vision of ecological living.

Effect of Different Substrates on Growth and Nutrient Absorption of Cinnamomum chekiangense Seedlings

Cinnamomum chekiangense is an important and precious tree species. In vigorously promoting precious tree species for the afforestation, the cultivation of high-quality container seedlings is the key to the success of afforestation, and the seedling substrate directly determines the quality of seedlings. In this paper, 1-year-old seedlings of C. chekiangense were selected as the research object, using potted culture method to study the effects of 5 substrates (yellow soil, sawdust, peat) on seedling plant height, ground diameter, biomass growth and accumulation of nitrogen, phosphorus and potassium, in order to screen out the suitable substrate ratio for the cultivation of the container seedlings of the C. chekiangense and provide the basis for the cultivation of high-quality container seedlings. The results showed that A3 (yellow soil∶peat∶sawdust=40∶30∶30) substrate was most conducive to the growth of C. chekiangense, and the plant height and ground diameter were significantly higher than A5 (P<0.05). The leaves, branches, roots and total biomass of C. chekiangense cultivated with A3 substrate were largest, which were 33.63, 39.57, 48.43, 121.64 g·plant−1, respectively; significantly higher than other treatments (P<0.05). The accumulation of nitrogen, phosphorus, and potassium in the whole plant of C. chekiangense cultivated with A3 substrate were the best, which were 3168.8, 137.3, 673.1 mg·plant−1 respectively; Gray correlation analysis method evaluation showed that A3 substrate was the best substrate for the growth of the C. chekiangense container seedlings.

Salinity and temperature influencing seed germination of Mediterranean Aleppo pine (Pinus halepensis Mill.): an ecological adaptation to saline environments

In Mediterranean basin, Pinus halepensis Mill. is the dominant conifer used in afforestation and landscape projects. The ecological, aesthetic and commercial benefits make this conifer a precious tree for both woody production and land rehabilitation. Nevertheless, detailed studies on the adaptation of this tree to abiotic environmental constraints in the Mediterranean areas remain limited up until now. Therefore, laboratory experiments were conducted to assess the effects of the interactive impact of temperatures and salinity on the germinability potential of P. halepensis seeds. The cones of P. halepensis used in this experiment were harvested from the Gotaïa forest at Djelfa province, Algeria. The seeds were removed from their cones and surface-sterilized by soaking for five min in 10% NaClO. Seeds were germinated at three temperature regimes (10–20 °C, 15–25 °C and 20–30 °C) and four levels of salinity (0, 50, 100, and 150 mM NaCl) at photoperiodic lighting (16 h of light : 8 h of dark). For each treatment 04 replicates of 25 seeds were placed in Petri dish with 5 ml of test solutions. A completely randomized design (CRD) was used for the experiment. Results revealed that the uppermost germinability was recorded in distilled H2O and the progressive enhancement of NaCl significantly (P &lt; 0.001) suppressed germination. At 15–25 °C (dark : light thermoperiod), P. halepensis seeds showed approximately 90% of germination at 0 mM NaCl. However less germination percentage (GP) was obtained at 10–20 °C and 20–30 °C. Values of Timson’s index were also suppressed significantly (P &lt; 0.001) with an increase under salt stress at all thermoperiods but at least at 15–25 °C. These funding suggest that seeding of P. halepensis may be an effective path for rehabilitation of degraded lands where salinity and drought are major features of the arid ecosystems. Yet, this conclusion still needs verification by field experiments. Key words: Pinus halepensis; arid zones; sowing dates; afforestation; salt tolerance

Genetic Diversity and Population Differentiation of Pinus koraiensis in China

Pinus koraiensis is a well-known precious tree species in East Asia with high economic, ornamental and ecological value. More than fifty percent of the P. koraiensis forests in the world are distributed in northeast China, a region with abundant germplasm resources. However, these natural P. koraiensis sources are in danger of genetic erosion caused by continuous climate changes, natural disturbances such as wildfire and frequent human activity. Little work has been conducted on the population genetic structure and genetic differentiation of P. koraiensis in China because of the lack of genetic information. In this study, 480 P. koraiensis individuals from 16 natural populations were sampled and genotyped. Fifteen polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers were used to evaluate genetic diversity, population structure and differentiation in P. koraiensis. Analysis of molecular variance (AMOVA) of the EST-SSR marker data showed that 33% of the total genetic variation was among populations and 67% was within populations. A high level of genetic diversity was found across the P. koraiensis populations, and the highest levels of genetic diversity were found in HH, ZH, LS and TL populations. Moreover, pairwise Fst values revealed significant genetic differentiation among populations (mean Fst = 0.177). According to the results of the STRUCTURE and Neighbor-joining (NJ) tree analyses and principal component analysis (PCA), the studied geographical populations cluster into two genetic clusters: cluster 1 from Xiaoxinganling Mountains and cluster 2 from Changbaishan Mountains. These results are consistent with the geographical distributions of the populations. The results provide new genetic information for future genome-wide association studies (GWAS), marker-assisted selection (MAS) and genomic selection (GS) in natural P. koraiensis breeding programs and can aid the development of conservation and management strategies for this valuable conifer species.