Search Results (16)

In this study, the morphological and anatomical characteristics of the growth of the internal ovules and the dynamic changes in the content of endogenous hormones during the development of Korean pine (Pinus koraiensis Siebold & Zucc.) cones were investigated in detail and their interrelationships determined. In addition, morphological examinations, paraffin section, analysis and enzyme immunoassays were performed to observe the growth and development as well as the fertilization stages of the ovules of P. koraiensis from July of the pollination year to June of the following year. From July of the pollination year to May of the next year, the increase in the content of indoleacetic acid (IAA) and gibberellin and a decrease in the content of abscisic acid (ABA) in the pollination year correlated with the division of the gametophyte free nuclei. It was observed that the levels of IAA, ABA, zeatin riboside (ZR) and isopentenyl adenosine (IPA) initially decreased and then increased during overwintering, which was interpreted as a symptom of adaptation of P. koraiensis ovules to low temperatures. At the end of overwintering, the increase in IPA, ZR and ABA levels was associated with the development of the female gametophyte. The week before fertilization was identified as the stage of oocyte division, in which growth-promoting hormones dominate. During the week of fertilization, the increase in the level of growth-inhibiting hormones correlated with fertilization. After fertilization, the increase in the level of growth-promoting hormones also correlated with early embryonic development. The levels of endogenous hormones were observed to change dynamically with the development of P. koraiensis oocytes, indicating their important role. The results of this study provide the morphological and anatomical basis for related studies on the development of the ovarian strobilus in gymnosperms. Full article

Korean pine (Pinus koraiensis Siebold & Zucc.) is an important timber and economic tree species in northeast China. Its seeds serve as both a primary means of propagation and a significant economic product. In this study, we identified 12 full-length MADS-box genes based on the Korean pine flower-induced transcriptome data available in our laboratory. These genes were identified through multiple sequence alignment and screening for conserved structural domains. We analyzed the genetic relationships of these genes and predicted their physicochemical properties. Additionally, we examined the expression patterns of three SHORT VEGETATIVE PHASE (SVP) genes across different tissues and developmental stages of Korean pine. The results indicate that the amino acid composition, molecular weight, isoelectric point, and other physicochemical properties of the MADS-box gene family in Pinus koraiensis are generally similar, though some individual variations are observed. A total of 12 MADS-box family genes were identified from the Korean pine transcriptome, distributed across five subfamilies. Conserved motif analysis revealed that these genes share similar conserved sequences. Structural and physicochemical analyses showed that genes with similar sequences exhibited comparable characteristics. Expression levels of the SVP genes varied significantly across different developmental stages and tissues, with the expression of the three SVP genes in leaves being markedly higher than in buds (approximately 200-fold). The expression levels of these genes in leaves were not only higher than in buds but also exceeded those in other tissues. Based on these findings, we conclude that these three SVP genes primarily play a suppressive role in the process of flower bud formation, helping Korean pine maintain a juvenile state under certain conditions, and are also involved in the growth and development of its leaves. This research provides a basis for future studies on the flowering induction mechanism in Korean pine. Full article

Herein, we explored the ecologic niches of generalist and specialist species within the subalpine vegetation zone, a habitat of Abies sp. distributed throughout South Korea and China. We included Abies sp. habitats in inland areas of South Korea and parts of the Manchurian region of China. Rhododendron schlippenbachii Maxim., Acer pseudosieboldianum (Pax) Kom., Picea jezoensis (Siebold & Zucc.) Carrière, Betula ermanii Cham., Acer komarovii Pojark., Pinus koraiensis Siebold & Zucc., Betula davurica Pall., Betula costata Trautv., Quercus mongolica Fisch. ex Ledeb, and Sorbus commixta Hedl. were selected as generalist species. Betula chinensis Maxim., Betula platyphylla var. japonica (Miq.) H. Hara, Euonymus pauciflorus Maxim., Salix maximowiczii Kom., Cornus walteri F.T. Wangerin, Carpinus laxiflora (Siebold & Zucc.) Blume, Populus davidiana Dode, Philadelphus tenuifolius Rupr. & Maxim., Rhododendron brachycarpum D. Don ex G. Don, and Larix olgensis var. koreana (Nakai) Nakai were selected as specialist species. NMS ordination analysis showed that specialist, generalist, and other plant species distribution correlated with basal area at breast height, stand density, and species diversity index. Generalist species could be grouped based on Quercus sp., Betula sp., and Acer sp. niche spaces. Specialist species shared ecological niches with plant species found in the limestone zone, sedimentary rock zone, and valley area. Full article

Pine wilt disease, caused by the pinewood nematode, affects Pinus densiflora, P. koraiensis Siebold and Zucc., and P. thunbergii Parl. in South Korea. It is primarily spread by vectors such as Monochamus alternatus Hope and M. saltuarius (Gebler). However, biological control research in this context remains limited in South Korea. We identified 15 parasitoids of these vectors, namely, two ectoparasitic larval parasitoids, Cyanopterus flavator (Fabricius) and Spathius verustus Chao, both in Braconidae, Hymenoptera. A field survey was conducted in Pohang from 2018 to 2020 to elucidate the ecological and biological characteristics of these parasitoids. The average parasitism rates of C. flavator were 6.3% and 1.0%, whereas those of S. verustus were 0.7% and 0.5% on M. alternatus and M. saltuarius, respectively. Both C. flavator and S. verustus appeared to prefer M. alternatus to M. saltuarius, but a statistically significant difference was observed only for C. flavator (p < 0.001). The peak season and tree height with the highest parasitism rate of C. flavator coincided with the period when M. alternatus larvae lived beneath the bark and the highest larval density of M. alternatus and M. saltuarius occurred in pine trees. These findings provide valuable information for determining the optimal release time and height for C. flavator to achieve effective biological control. Full article

Soil enzymes mediate organic matter decomposition and nutrient cycling, and their stoichiometry can indicate microbial nutrient demands. However, research on the variations in soil enzymes and microbial nutrient limitation under different temperate forest types still lacks insight. In this study, we sampled soils under five typical forest types (including Betula platyphylla Suk. forest, Fraxinus mandschurica Rupr forest, Larix gmelinii (Rupr.) Kuzen. forest, Populus davidiana Dode forest, and Pinus koraiensis Siebold et Zucc.forest) in the temperate climatic region of northeast China. Soil enzyme activities and soil microbial community composition and diversity were determined for each, and vector analysis was used to quantify the value of microbial limitation. The results showed that soil enzyme activity, enzyme stoichiometry, and microbial community structure were significantly different among the five temperate forest types. The ratios of soil C:N:P acquiring enzyme activity were close to 1:1:1. All the forests showed prevalent P limitation over N limitation (all vector angles > 45°), and the degree of impact varied among different forest types. Redundancy analysis (RDA) and Pearson’s test demonstrated that soil enzyme activities and microbial nutrient limitation were mainly determined by soil physical properties and microbial community. These results contribute to understanding the mechanisms that link plant composition, soil enzyme activity, and microbial nutrient limitation in temperate forests. Full article

Brown-rot fungi are large fungi that can decompose the cell walls of wood; they are notable for their secretion of diverse and complex enzymes that synergistically hydrolyze natural wood cellulose molecules. Fomitopsis pinicola (F. pinicola) is a brown-rot fungus of interest for its ability to break down the cellulose in wood efficiently. In this study, through a combination of rDNA-ITS analysis and morphological observation, the wood decay pathogen infecting Korean pine (Pinus koraiensis Siebold and Zucc.) was identified. Endoglucanase (CMCase) and β-glucosidase were quantified using the DNS (3,5-Dinitrosalicylic acid) method, and the cellulase activity was optimized using a single-factor method and orthogonal test. The results revealed that the wood-decaying fungus NE1 identified was Fomitopsis pinicola with the ITS accession number OQ880566.1. The highest cellulase activity of the strain reached 116.94 U/mL under the condition of an initial pH of 6.0, lactose 15 g·L⁻¹, KH₂PO₄ 0.5 g·L⁻¹, NH₄NO₃ 15 g·L⁻¹, MgSO₄ 0.5 g·L⁻¹, VB₁ 0.4 g·L⁻¹, inoculated two 5 mm fungal cakes in 80 mL medium volume cultured 28 °C for 5 days. This laid a foundation for improving the degradation rate of cellulose and biotransformation research, as well as exploring the degradation of cellulose by brown rot fungi. Full article

Forests play a crucial role in South Korea’s carbon neutrality goal and require sustainable management strategies to overcome age-class imbalances. The Generic Carbon Budget Model (GCBM) offers a spatially explicit approach to simulate carbon dynamics at a regional scale. In this study, we utilized the GCBM to analyze the carbon budget of forests in South Korea and produce spatiotemporal maps for distribution of the forest biomass. The growth parameters of five representative tree species (Pinus densiflora Siebold & Zucc., Larix kaempferi Carr., Pinus koraiensis Siebold & Zucc., Quercus mongolica Fisch. ex Ledeb., Quercus variabilis Blume), which are the main species in South Korea, were used to operate the model. In addition, spatial data for harvest and thinning management activities were used to analyze the effects of anthropogenic activities. In 2020, the aboveground and belowground biomass were 112.98 and 22.84 tC ha⁻¹, and the net primary productivity was 8.30 tC ha⁻¹ year⁻¹. These results were verified using comparison with statistics, a literature review, and MODIS NPP. In particular, broadleaf is higher than conifer forest in net primary production. The Canadian GCBM with Korean forest inventory data and yield curves successfully estimated the aboveground and belowground biomass of forests in South Korea. Our study demonstrates that these estimates can be mapped in detail, thereby supporting decision-makers and stakeholders in analyzing the carbon budget of the forests in South Korea and developing novel schemes that can serve regional and national aims related to forest management, wood utilization, and ecological preservation. Further studies are needed to improve the initialization of dead organic matter pools, given the large-scale afforestation efforts in recent decades that have established South Korea’s forests on predominantly non-forest sites. Full article

Stilbenes are a large group of plant phenolic compounds that have a wide range of biologically active properties, such as antioxidant, immunomodulatory, anti-inflammatory, and anti-angiogenic effects. In plants, stilbenes are involved in the defense against environmental stresses, including fungal infections and insect attacks. The biosynthesis of stilbenes is well described for those plant species where resveratrol and its derivatives are the predominant stilbenes. However, there is little information on stilbene biosynthesis in the Pinaceae family, although the highest content of stilbenes was found in plants of this family. In this study, seasonal variations in stilbene compositions and contents in different parts of Pinus koraiensis was described (needles, bark, wood, young branches, and strobiles). HPLC-ESI-MS analysis showed the presence of seven stilbenes in P. koraiensis: t-astringin; t-piceid; cis-piceid; t-isorapontin; t-pinostilbenoside; t-resveratrol; and t-pinostilbene. Glycosylated and methylated forms of stilbenes, such as t-astringin, t-piceid, and t-pinostilbenoside, prevailed over other stilbenoids. The highest content of stilbenes was detected in the bark collected in spring and winter (up to 54.8 mg/g dry weight). The complete protein-coding sequences of three stilbene synthase genes, PkSTS1, PkSTS2, and PkSTS3, were obtained from the RNA isolated from the P. koraiensis needles. The expression of the PkSTS1, PkSTS2, and PkSTS3 genes was analyzed using real-time PCR and frequency analysis of cloned RT-PCR products in the needles of P. koraiensis collected in different seasons. Thus, we first analyzed stilbene biosynthesis in the different organs of pine P. koraiensis and PkSTS expression depending on the year seasons. Full article

The accurate assessment of forest biomass is vital to climate change mitigation. Based on forest survey data, stand biomass models can effectively assess forest biomass carbon at large scales. However, traditional stand biomass models have ignored the potential effects of the climate on stand biomass estimation. There is still a lack of research on whether or not and in what ways the effects of the climate reduce uncertainty in biomass estimation and carbon accounting. Therefore, two types of stand biomass models, including basic stand biomass models (BBMs) and climate-sensitive stand biomass models (CBMs), were developed and tested using 311 plantation plots of Korean pine (Pinus koraiensis Siebold & Zucc.), Korean larch (Larix olgensisi A. Henry), and Mongolian pine (Pinus sylvestris var. mongolica Litv.) in Northeast China. The two types of models were developed by applying simultaneous equations based on nonlinear, seemingly unrelated, regression (NSUR) to ensure additivity of the stand total and components biomass (root, stem, branch, and needle). The results of fitting and leave-one-out cross-validation (LOOCV) indicated that the CBMs performed better than the corresponding BBMs. The RMSEs of the stand total biomass decreased by 3.5% to 10.6% for the three conifer species. The influence of temperature-related climate variables on the biomass of stand components was greater than that of precipitation-related climate variables. The sensitivity of the three conifer species to climate variables was ranked as Korean pine > Mongolian pine > Korean larch. This study emphasizes the importance of combining climate variables in stand biomass models to reduce the uncertainty and climate effects in forest biomass estimation, which will play a role in carbon accounting for forest ecosystems. Full article

The pine wood nematode (PWN), Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle., is one of the most dangerous invasive species in the world, causing devastating pine wilt disease (PWD) in pine trees from many countries. The PWN is now established in 18 provinces in China from the south to north, and it has expanded to some areas of Liaoning Province with temperatures that are beyond the ideal range. It has been reported that Pinus koraiensis Siebold & Zucc., one of the representative pine trees of Liaoning Province, has been infected by PWNs. To investigate the pathogenicity of the PWN in P. koraiensis, the reproductive ability of PWNs on fungal culture was compared among three isolates: QH-1, NM-1, and CM-1 (QH-1 from Liaoning Province, NM-1 from Nanjing Province, and CM-1 from Chongqing Municipality). Four-year-old P. koraiensis seedlings were inoculated with QH-1, NM-1, and CM-1 at a rate of 2000 per seedling. Pathogenicity, external symptoms, and nematode migration were all monitored on a daily basis over the next few days. The results from the experiment showed that all three PWN isolates caused wilt in P. koraiensis seedlings, with QH-1 being more virulent than NM-1 and CM-1. In addition, QH-1 exhibited greater reproductive and migration abilities in the seedlings than NM-1 and CM-1. These results indicate that the virulence of the B. xylophilus isolates QH-1, NM-1, and CM-1 can differ in terms of seedling mortality, migration ability, and reproductive ability (in trees). Full article

The objectives of this study were to develop site index and variable-density yield models for Korean red pine (Pinus densiflora Siebold & Zucc.), Korean white pine (P. koraiensis S. & Z.), and Japanese larch (Larix kaempferi (Lamb.) Carrière) in Korea. The data were collected between 2012 and 2021 from repeatedly measured empirical plots in each target stand in the North Central region of Korea: Gangwon and North Gyeongsang provinces. To develop the site index for each species, a dominant height growth model by species was developed using the Chapman–Richards function. The site index was computed with a base age of 40 years and used as an independent variable to predict the stand volume. To develop the variable-density yield models, three stand density variables, the stand age, and the site index were applied. The stand density variables used were the stand basal area, the number of trees per hectare, and the relative density. All the models were successfully developed with significant parameters and reasonable fit statistics, and the residuals analyzed presented unbiased scatter plots. Yield models with the stand basal area, or the number of trees, can be used to predict the stand volume. The yield model with relative density was flexible to apply across the stand age because the input of the absolute stand density was not required. Model simulation and comparisons with other studies also supported the applicability of the models developed in this study. The models were found to be highly applicable for predicting and simulating these targeted stands, particularly in Korea. Full article

Very high resolution satellite imageries provide an excellent foundation for precise mapping of plant communities and even single plants. We aim to perform individual tree recognition on the basis of very high resolution RGB (red, green, blue) satellite images using deep learning approaches for northern temperate mixed forests in the Primorsky Region of the Russian Far East. We used a pansharpened satellite RGB image by GeoEye-1 with a spatial resolution of 0.46 m/pixel, obtained in late April 2019. We parametrized the standard U-Net convolutional neural network (CNN) and trained it in manually delineated satellite images to solve the satellite image segmentation problem. For comparison purposes, we also applied standard pixel-based classification algorithms, such as random forest, k-nearest neighbor classifier, naive Bayes classifier, and quadratic discrimination. Pattern-specific features based on grey level co-occurrence matrices (GLCM) were computed to improve the recognition ability of standard machine learning methods. The U-Net-like CNN allowed us to obtain precise recognition of Mongolian poplar (Populus suaveolens Fisch. ex Loudon s.l.) and evergreen coniferous trees (Abies holophylla Maxim., Pinus koraiensis Siebold & Zucc.). We were able to distinguish species belonging to either poplar or coniferous groups but were unable to separate species within the same group (i.e. A. holophylla and P. koraiensis were not distinguishable). The accuracy of recognition was estimated by several metrics and exceeded values obtained for standard machine learning approaches. In contrast to pixel-based recognition algorithms, the U-Net-like CNN does not lead to an increase in false-positive decisions when facing green-colored objects that are similar to trees. By means of U-Net-like CNN, we obtained a mean accuracy score of up to 0.96 in our computational experiments. The U-Net-like CNN recognizes tree crowns not as a set of pixels with known RGB intensities but as spatial objects with a specific geometry and pattern. This CNN’s specific feature excludes misclassifications related to objects of similar colors as objects of interest. We highlight that utilization of satellite images obtained within the suitable phenological season is of high importance for successful tree recognition. The suitability of the phenological season is conceptualized as a group of conditions providing highlighting objects of interest over other components of vegetation cover. In our case, the use of satellite images captured in mid-spring allowed us to recognize evergreen fir and pine trees as the first class of objects (“conifers”) and poplars as the second class, which were in a leafless state among other deciduous tree species. Full article

Exploring carbon allocation pattern and its influencing factors is of great significance for estimating the carbon sequestration rate and potential of forest ecosystems. Here, we investigate all carbon pool components (including above and belowground biomass of tree, shrub and herb layers, and dead biomass and soil carbon pools) in four successional stages of broad-leaved and Korean pine (Pinus koraiensis Siebold & Zucc.) mixed forests in Northeast China. We explore the change of allocation among carbon pools with succession and examine the relative importance of succession, stand age, and stand factors on carbon allocation pattern. Our results illustrate that above- and belowground vegetation carbon increase as maximum tree height increases. Below- to aboveground vegetation carbon ratio (R/S ratio) decreases significantly with succession and increases significantly as mean diameter at breast height (DBH) increases, but does not significantly correlate with stand age. With succession and increasing stand age, understory (shrub, herb) to tree carbon ratio (understory/tree ratio) and soil to vegetation carbon ratio (soil/vegetation ratio) decrease significantly. The joint effect of succession, stand age, and stand factors have the largest contribution on above- and belowground vegetation carbon and understory/tree ratio (26.83%, 27.93%, and 49.48% of variations explained, respectively). As for the pure effects, stand factors explain the largest proportion of variations in vegetation aboveground carbon (11.25%) and soil carbon (20.18%). Meanwhile, succession is the variable with the largest contribution to vegetation belowground carbon (12.64%), R/S ratio (21.83%), understory/tree ratio (25.84%), and soil/vegetation ratio (6.68%). Overall, these results suggest that species composition change during forest succession, instead of stand factors and stand age, is the main driver of forest vegetation carbon allocation. In contrast, stand factors play a major role in soil carbon allocation. Our findings suggest more studies to better understand the role of species composition (in addition to stand factors and age) on biomass allocation, and the influence of stand factors and litterfalls on soil carbon sequestration, which are critical to improve forest management strategies (e.g., adjustment of species composition and forest structure) to increase the future ability of forest carbon sequestration. Full article

A need is growing to plant superior Korean pine (Pinus koraiensis Siebold & Zucc.) seedlings to cope with the degradation of secondary forests in Northeast Eurasia. The goal of this study was to detect the physiological effect on the quality of Korean pine seedlings exposed to a range of spectra. One-year-old seedlings (n = 6) were cultured in three light-emitting diode (LED) spectra (69‒77 μmol m⁻² s⁻¹) of 13.9% red (R) + 77.0% green (G) + 9.2% blue (B) (R1BG5), 26.2% R + 70.2% G + 3.5% B (R2BG3), and 42.3% R + 57.3% G + 0.4% B (R3BG1). The spectrum of high-pressure sodium (HPS) lamps (43.9% R + 54.7% G + 1.5 B) was taken as the reference. Results showed that LED-lighting resulted in shorter seedlings with a greater diameter, shoot biomass, assessed quality, and sturdiness compared to those under the HPS-lighting. The R3BG1 spectrum reduced the shoot nitrogen (N) deficiency induced by the HPS spectrum, while the R1BG5 treatment induced a steady-state uptake of N and phosphorus (P) in whole-plant organs. The R1BG5 spectrum also resulted in a higher soluble sugar concentration and higher activities of glutamine synthetase and acid phosphatase in needles compared to the control. Seedlings in the R2BG3 spectrum had the highest concentrations of chlorophyll and soluble protein in the leaves. Overall, the R-high LED-spectrum could stimulate biomass accumulation in shoot, but meanwhile resulted in a P deficiency. Hence, the LED lighting in the R1BG5 spectrum is recommended to promote the quality of Korean pine seedlings. Full article

Tropical cyclones (hurricanes and typhoons) cause large-scale disturbances in forest ecosystems all over the world. In the summer of 2016, a strong tropical cyclone named Lionrock created windthrow patches in the area of more than 400 km² on the forested eastern slopes of the Sikhote-Alin Range, in the Russian Far East. Such large-scale forest destruction by wind had never been recorded in the area prior to this event. We examined the tropical cyclone impact upon the forest composition, structure and tree mortality rates on two study sites (1 ha and 0.5 ha in size)—a contiguous windthrow patch site, and a site with partial canopy damage. Korean pine (Pinus koraiensis Siebold and Zucc.), Manchurian fir (Abies nephrolepis Trautv.) and Dahurian larch (Larix cajanderi Mayr.) were the primary tree species represented in the affected forest communities. Combined with the partial canopy damage, 7.7% of trees were blown down by the disturbance event. We determined that this one event mortality rate nearly equaled the average mortality rate for a ten year period for these forests (8.5 ± 4.0%) under normal conditions (no large-scale disturbances). Within a contiguous windthrow patch, tree mortality was determined to be 52.6%, which is significantly higher than the cumulative tree loss for the previous 50 years (42.4%). A substantial portion of thinner-stemmed trees (DBH (diameter measured at breast height) < 30 cm) were wind snapped, and those with larger diameters (DBH > 60 cm) were uprooted. Our results indicate that the probability of tree loss due to catastrophic wind loads increases as a result of the decrease in local density. We believe that tree loss estimates should include the impacts within contiguous patches of windthrows, as well as the patches with only partial tree canopy damage. Strong wind impact forecasting is possible with accounting for species composition within the stand sites and their spatial structure. Full article