The production and circulation of forest observation information form the foundation and precursor for the advancement of smart forestry practices, with observation equipment and survey personnel being the primary producers of this information. This article takes the history, current state, and future of the forest observation instrument technology system as the starting point, and is supported by the development trajectory of fundamental public technology, to analyze in depth the coupling between forest observation instruments and forest observation requirements. The traditional forest observation instrument systems can no longer meet the growing needs of forestry surveys in terms of timeliness and accuracy, and they are high isolation, low integration, cumbersome operation, and low efficiency. This is mainly attributed to the current focus on mature instrument usage and data analysis in forest observation, with instrument development prioritizing algorithm compensation and the integration of third-party components over physical structure design. To address the lack of updates in basic measurement principles and the delay in setting forest observation standards, the article elaborates on the current and future joint modes of observation instruments, and analyzes the possible development status and application prospects of forest observation instrument joint modes from the logical architecture to the physical technology level. Finally, based on current trends in fundamental technological development, the article speculates the potential new forms of forest observation instruments and forecasts novel intelligent forest observation systems that may be realized in China in the near future.

Objective: Tree crown architecture and the leaf optical properties and spatial distribution in the canopy are closely related to the absorption and interception of solar shortwave radiation. It is important to quantitatively simulate and characterize the solar radiation distribution and interception in the forest canopy, and invert the radiation flux changes of solar shortwave radiation in different forest canopy under spatiotemporal transformation, which would provide a theoretical foundation for forest cultivation practices and forest quality enhancement. Method: Firstly, the public dataset and the terrestrial laser scanned points of trees on campus were used, combined with the designed machine vision algorithm, to separate branches and leaves, and perform individual leaf segmentation from the scanned points. Meanwhile, the elliptical and cylindrical geometric primitives with proper size were employed to approximate the leaves and branches, respectively, and the real model of forest trees was reconstructed. Secondly, the computer graphics methods, combined with the longitude and latitude of the study area and the time of day, were used to simulate the incident solar beams with corresponding solar altitude and azimuth angles. Meanwhile, the bi-directional reflectance and transmittance distribution functions of physics coupled with Monte Carlo ray tracing method were employed to simulate the events of reflected and transmitted solar beams collided with leaf surfaces in the canopy. Finally, based on the average roughness and refractive index of the leaves of different tree species measured by the instrument, combined with ray tracing algorithm, the calculation of the distribution of shortwave radiation within the canopy and the assessment of the canopy light interception efficiency were conducted. Result: The direct, reflected and transmitted solar radiation fluxes for the four tree crowns of different tree species (mango, rubber, crape myrtle, and cherry) and a camphor forest in both spatial and temporal dimensions were calculated. The results showed that the direct radiation flux accounted for roughly 86%, the reflected radiation flux accounted for about 5%, and the transmitted radiation flux accounted for roughly 9%. The crown with higher leaf area index (LAI) intercepted more direct and transmitted light. When the solar altitude angle was small (in the morning or afternoon), the oblique solar beams after being reflected always had a high occurrence probability of collision with other leaves in the tree crown, resulting in an increment in the reflected radiation flux. Meanwhile, due to the phototaxis of forest trees, the interception rate of light by the crown at noon was approximately 10% higher than that in the morning and afternoon. The absolute error between the interception ratio of tree crown radiation flux calculated using this research method and the measured results of handheld photoelectric instruments in the sample site was less than 6%. Conclusion: By using the multidisciplinary perspectives incorporating surveying science, computer graphics and forestry, this study reconstructs the real morphological structure of the target trees from the scanned points. The physical models (the bi-directional reflectance and transmittance distribution functions) and Monte Carlo ray-tracing method are used to simulate the propagation process of solar beams in the tree crown. The field measurements verify the accuracy of the quantitative results regarding the distribution of solar shortwave radiation in the forest canopy and the intercepted canopy radiation flux by our method. The work has great significance for studying solar radiation absorption, investigating the coupling relationship between radiation regime and canopy morphological structure, and evaluating the radiation transfer model within tree canopies with varying phenotypic traits.

Objective: This study aims to analyze the spatial distribution pattern and intraspecific competition intensity variation of Populus euphratica tree populations under different groundwater depth levels in arid regions, and explore the response characteristics of population spatial structure to the arid environmental condition. Method: Fifteen plots of 50 m × 50 m in a natural P. euphratica forest were set up at equal distances within a range of 1 000 m away from the river channel at three cross-sections in the lower reaches of the Tarim River. The terrestrial laser scanning (TLS) technique was used to acquire the three-dimensional structural parameters of trees in the plots. The spatial distribution indicators such as aggregation index (R), David-moor clustering index (I), point pattern function g(r), and competition index (CI) were used to analyze the spatial distribution pattern and intraspecific competition intensity. Result: 1) The R and I indices indicated that P. euphratica population structure mainly showed aggregated patterns at the different groundwater levels in the study area. 2) The analysis of the g(r) function values obtained from the radius (r) distance of 0–25 m away from a tree in various plots showed that most of the plots exhibited an aggregated distribution pattern within r < 5 m distance, and changed to random distribution pattern with r > 5 m. With the increase in groundwater depth, the tree's aggregation distance r will decreased. 3) The analysis results of the point pattern function g₁₂(r) indicated that there were differences in their distribution patterns among different age-class trees. Middle-aged trees mainly showed an aggregated pattern, while other age-class trees showed a random distribution pattern. There was a positive correlation between middle-aged trees and young or mature trees, showing a mutually promoting relationship, while trees of other age classes did not show significant correlations. 4) The average CI index showed a decreasing trend with the increase of distance from the river channel, and the individual tree CI decreased with the increase of DBH. Conclusion: P. euphratica population in the lower reaches of the Tarim River shows an aggregated distribution pattern at small observation scales and however exhibits to a random distribution pattern characteristics with the increase of scale. As the distance from the river increases and the groundwater level gradually decreases, the stand density decreases and the average competition intensity within the species weakens, resulting in a declining trend of trees.

Objective: A large number of training samples are needed for leaf identification based on deep learning. Insufficient sample size and single image style can affect the identification accuracy. However, studying the use of a small number of samples for leaf image reproduction and style transformation can greatly reduce the burden of data collection, which would provide effective technical means and theoretical support for improving forestry survey informationize and intelligence. Method: The leaf images of 6 tree species were collected to establish a dataset, and the light-weight generating adversarial networks (GAN) was introduced to propagate images and style translation, and expand the manually shot leaf dataset. Four deep convolutional neural networks (DCNN), AlexNet, GoogLeNet, ResNet34 and ShuffleNetV2, were applied to train the dataset and the original dataset, respectively, by which the role of image augmentation techniques of GAN in leaf recognition was analyzed. The optimal model was selected based on performance indicators such as model accuracy and training time, and the learning rate was adjusted. Finally, the test samples were used to verify the optimized model, and the feasibility and significance of the method in practice were analyzed. Result: The samples with high definition and high fidelity were generated based on generative adversarial networks, which was able to effectively enrich the sample category, and obtain leaf images with different shapes, and health conditions at different seasons. Compared with the original dataset, AlexNet, GoogLeNet, ResNet34 and ShuffleNetV2 all showed smaller training errors and higher validating accuracy on new dataset during the model training. Among them, the ShuffleNetV2 model with a learning rate of 0.01 had the best training effect on this dataset, whose highest validating accuracy was 99.7%. The model was verified by using the test samples and a good recognition performance on each leaf was achieved, and the overall recognition accuracy of the model was up to 99.8%. Compared with the ordinary DCNN without GAN, the model proposed in this paper significantly improved the accuracy of leaf identification. Conclusion: GAN can effectively expand the number of images and transform the style of images. The combined use of GAN and DCNN can significantly improve the accuracy of leaf identification, thus it can be applied in forest leaf identification.

Objective: In this study, cloud computing method was used to simulate the spread process of forest fire and plan the fire emergency path, so as to promote the rescue forces to quickly and efficiently reach the designated place, and to reserve enough time for arranging forest fire prevention measures. This study also puts forward constructive suggestions for forest fire emergency response and prevention planning in Dongchang District, Tonghua City, Jilin Province. Methods: An on-site investigation was conducted in Dongchang District, Tonghua City, Jilin Province, and then the model deduction was carried out. With a view to the differences between single-source and multi-source forest fires, the emergency path planning model and Dijkstra algorithm were used to simulate and calculate the shortest rescue path in the case of single-source forest fires, and the multi-source forest fire priority theory was incorporated to maximize the utilization of rescue resources. The FARSITE model was used to simulate the spread rate of forest fires in regional examples, and real-time data of each stage after forest fires occurrence were obtained. In considering the resource layout near forest fires and road traffic capacity comprehensively, the rescue path was calculated and the fire prevention road layout was carried out, to verify the feasibility of the method, and the rescue path of forest fires emergency response was intelligently optimized. Result: Based on the formula of a single fire point in a general forest fire occurrence, the priority theory was introduced for two or more fire points, and then Dijkstra algorithm was used to deduce in turn according to the severity of the fire. In addition, μ, as a capacity coefficient, was added to consider the influence of road conditions and road attributes on the rescue transit time, and obtain a new path formula. By using the FARSITE model, the spread rate of the "5.3" general forest fire (20100503-220502-01) in 2010 was simulated. In five hours after the fire started, if there was no effective human intervention, the fire would turn into a major forest fire and spread to the residential areas. Due to the influence of wind direction, the fire priority on the northeast of the fire source would be higher than that on the north. If there are conditions for simultaneous rescue, the emergency resources should be tilted according to the priority. Conclusion: The simulation results show that by using the emergency path planning model, Dijkstra algorithm and priority theory, the acquisition rate of rescue paths can be improved, and resources and personnel can be allocated in advance. FARSITE simulation combined with fire road planning can effectively improve the efficiency of forest fire decision-making, and form a forest fire emergency response and prevention planning scheme with half the effort.

Objective: This study aims to explore the anatomical mechanisms that affect wood density and reveal the coordination and trade-off relationships of anatomy and physiological traits between stems and leaves traits can deepen the understanding of physiological and ecological mechanisms of different tree species adapting to the environment. Method: Eight common deciduous broad-leaved tree species in the natural forest of Baotianman were selected as the research objects. Twenty-one stem and leaf traits of these tree species, including wood density, xylem vessels and fibers and other anatomical traits, and leaf pressure volume curve parameters, were measured to explore the anatomical traits that determine wood density and to analyze the coordination and trade-off between stem and leaf traits. Result: 1) The wood density of 8 tree species in this study was not correlated with the proportions of the three major tissues that make up the xylem: vessels, parenchyma tissue and fiber tissue. Wood density was more influenced by traits of fiber cells. 2) The xylem traits that have the greatest impact on wood density was the ratio of fiber lumen to cross-sectional area, followed by the ratio of fiber wall to fiber cell, the ratio of fiber wall thickness to lumen diameter and the fiber cell wall thickness. 3) Wood density was negatively correlated with individual leaf area, relative water content at turgor loss point and elasticity modulus. 4) The relative water content at turgor loss point was positively related to hydraulic vessel diameter, maximum vessel diameter, mean vessel diameter, fiber cell lumen area and fiber cell lumen diameter, and negatively related to vessel density, the ratio of fiber wall thickness to lumen diameter and the ratio of fiber wall to cross-sectional area. Conclusion: The wood density is mainly determined by the fiber cell traits, rather than the traits of vessel and parenchyma tissue. The strong capacity of leaves to tolerate dehydration is coupled with the dense stem fiber cells and wood density.

Objective: To provide theoretical reference for afforestation and its stand management in key regions of Tibet, we investigated the difference and changing trends of soil physicochemical properties between planted region and its adjacent area where without planting in the mid-watershed of “One River and Two Tributaries”, Tibet. And the understanding of soil fertility for artificial afforestation was improved systematically to there. Method: In the July to November of 2016, soil samples from four layers (0?20, 20?40, 40?60, 60?80 cm) at the depth of 0?80 cm were surveyed for 54 couples of plots which contained artificial forest (planted region) and its control plot (adjacent to artificial forest, with the same initial conditions, CK). And the soil physicochemical properties such as soil organic matter(SOM), total nitrogen(TN), total phosphorus(TP), total potassium(TK), alkaline nitrogen(AN), available phosphorus(AP), available potassium(AK), soil density(BD), soil mass water content(MWC), pH, and soil particle-size distribution(PSD) were tested. The methods of Wilcoxon signed-ranks Test, soil nutrient classification, PCA were used to analyze and compare the effects of artificial afforest on soil physicochemical properties. Result: Comparing with CK, the BD, TP, and AP for artificial forests in the 0?80 cm soil layer decreased obviously by 6.0%, 10.5%, and 36.5%, respectively. And MWC, TN, SOM increased obviously by 22.4%, 28.6%, 16.8%, respectively. AP varied largest and TN had the highest increase. pH, AK, TK, AN, and PSD changed insignificantly. More than 63.1% of the plots were in slightly deficient level or more worse levels for nitrogen, phosphorus, potassium, and soil organic matter of the CKs, and TN was in the worst nutrient classification. That percentage became to more than 73% for the artificial forests, and AP was in the worst nutrient classification. The plots’ proportion of AP for transferring from no deficient level to deficient level was also the highest. For CKs and artificial forests, the value of soil nutrient classification were ranked as TP>AK>AP>TK>SOM>AN>TN(the nutrient status is better on the left of ‘>’ than that on the right, the same below), TP>AK>TK>TN>SOM>AN>AP, respectively. The soil fertility changed insignificantly, which was comprehensive influenced by SOM, TN, and sand content. Conclusion: In the mid-watershed of “One River and Two Tributaries”, where is the key region for artificial afforestation in Tibet, the artificial afforestation has a obviously influence on the soil physicochemical properties, such as BD, MWC, TN, TP, AP, and SOM. For the artificial forests, the soil physicochemical conditions with soil density, soil mass water content, soil organic matter, nitrogen become better. While the nutrient condition of phosphorus becomes worse. The soil is mostly lack of AP for artificial forests, and its severest nutrient limitation is phosphorus, which is nitrogen for CK. The improvement of soil fertility is limited by AP. Whether afforestation or not, the soil nutrients are generally deficient in there. The soil fertility management should be strengthened for artificial afforestation in Tibet, especially focusing on enhancement the total level of soil nutrients. To improve the afforestation effect and soil fertility, the use of organic fertilizer can be strengthened before afforestation, and the use of phosphate fertilizer can be highlight in the subsequent management.

Objective: With the sparse strip-planted Prunus sibirica plantation in the loess hilly region of southern Ningxia as an example, this study aims to reveal the spatio-temporal dynamics of soil moisture in different depths inside the forest belt (IFB) and between the forest belts (BFB) and the key environmental factors in order to provide a scientific basis for the restoration of forest-grass vegetation and efficient utilization of rainfall resources in the semi-arid area. Method: From 2020 to 2022, two sets of 200 cm-depth soil moisture sensors were respectively installed at sites of IFB and BFB in Pengyang County, Ningxia, to monitor the changes of volumetric soil moisture and soil temperature by stratified hourly method. At the same time, a meteorological station was set up to continuously monitor the meteorological conditions, such as near-surface precipitation, air temperature, and air relative humidity. Correlation analysis was applied to explore the response of soil moisture to the previous day's soil moisture, soil temperature and meteorological factors. Result: Both 2020 and 2021 were ordinary years, with precipitation of 467.4 mm and 440.8 mm, respectively, while 2022 was a dry year with precipitation of 354.8 mm. The mean volumetric soil moisture in ordinary year (2021, 17.0%) was significantly (P<0.05) higher than that in dry year (2022, 14.3%). Volumetric soil moisture increased linearly with soil depth, and its slope in BFB was higher than that in IFB, and the slope in ordinary year was higher than that in dry year. Volumetric soil moisture in 0–120 cm soil layer was higher in IFB (15.3%) than that in BFB (14.0%), while that in 120–200 cm soil layer was higher in BFB (17.6%) than that in IFB (16.8%). The coefficient of variation (CV) of volumetric soil moisture in 0–60 cm soil layer was higher in BFB (42.9%) than tht in IFB (37.8%), while that in 60~200 cm soil layer was higher in IFB (23.2%) than that in BFB (19.1%). The seasonal patterns of soil moisture variation were able to be divided into the relative stable period (from March to April), the depletion period (from May to August), the recovery period (from September to November) and the decline period (from December to February of the next year). The maximum value of soil moisture mostly appeared in April, and the minimum value appeared in August (the ordinary year) and December (the dry year). The vertical patterns of soil moisture variation in the soil profile were divided into the rapidly changing layer (0–50 cm), the active layer (50–90 cm), the sub-active layer (90–170 cm) and the relatively stable layer (170–200 cm). The correlation analysis showed that the daily soil moisture was most correlated with the soil moisture at the previous day (positively) and the soil temperature (negatively). The monthly soil moisture was most correlated with the soil temperature (negatively). Conclusion: The soil moisture IFB or BFB of the sparse banded A. sibirica plantation in the loess area of Ningxia fluctuates strongly in seasons and profiles. The fluctuation in the dry year is deeper than that in the ordinary year. The previous day's soil moisture, soil temperature and meteorological factors are the key factors affecting soil moisture in each profile level on a daily and monthly scale in low-flow and ordinary-flow years. Among them, the previous day's soil moisture and soil temperature are the main factors, and soil moisture in 120 cm depth is higher in IFB than that in BFB. The results of this study have a great guiding significance for scientific restoration of degraded vegetation and efficient utilization of soil moisture after horizontal ditch soil preparation in the semi-arid loess area of Ningxia.

Objective: By studying the characteristics of nocturnal sap flow and environmental driving factors in Pinus tabuliformis during the growing season, to reveal the characteristics of nocturnal sap flow component splitting, to discuss the correlation between components of nocturnal sap flow and meteorological factors, as well as the response of stem refilling to meteorological factors, and provide theoretical basis for the management decision of water resources and water-source conservation forests in rocky mountain area of North China. Method: Taking P. tabuliformis in rocky mountain area of North China as the research objection, 18 sample trees were selected according to the diameter size, using Granier Thermal Dispersion Probe (TDP) technique to continuously observe nocturnal sap flow during the growing season of 2014, combined with the weighing lysimeter meter and homemade micro-evapotranspiration meter to calculate the evapotranspiration and to resolve the destination of nocturnal sap flow; and to correlate nocturnal sap flow with meteorological factors such as soil water content, atmospheric temperature, humidity and photosynthetically active radiation to determine the main driving factors. Result: The results showed that: the nocturnal sap flow velocity gradually decreased on typical sunny days in June, July, August , and September, and was higher from 18:00 to 24:00 than from 00:00 to 05:00. The nocturnal sap flow was mainly used to refill the stem that had lost too much water during the day, so that the storage capacity of the stem of P. tabuliformis basically reached saturation by 24:00, so the nocturnal sap flow velocity tended to stabilize between 00:00 and 05:00. The proportion of nocturnal sap flow used for stem refilling (95.34%) was significantly higher than that used for nocturnal transpiration (4.66%), nocturnal stem refilling of P. tabuliformis was highly significantly positively correlated with vapor pressure deficit (R²=0.793, P < 0.01), while it was almost insensitive to soil water content (R²=0.105, P > 0.05), indicating that nocturnal sap flow was mainly influenced by vapor pressure deficit. Conclusion: Nocturnal sap flow during the growing season of P. tabuliformis in rocky mountain area of North China showed a gradual decrease over time. The vast majority of nocturnal sap flow was used for nocturnal stem refill, and among the meteorological factors, vapor pressure deficit was the main factor driving nocturnal stem refill and nocturnal sap flow(P < 0.01).

Objective: In this paper, we studied the growth and physiological characteristics of Sabina chinensis vulgaris container seedlings under high concentration salt stress, and the mitigation effect and difference of fulvic acid potassium on high concentration NaCl and CaCl₂ stress. It provides technical support for the management and maintenance of median strip of northern expressway in winter. Method: We used 2-year-old Sabina chinensis container seedlings as study materials during pot experiment, and normal growth as control. The effects of potassium fulvic acid (FA-K) at 0, 0.05%, 0.10%, 0.30% and 0.50% on alleviating high salt stress of 0.7% NaCl and CaCl₂ were investigated. The growth indexes of Sabina chinensis seedlings (seedling height growth, ground diameter growth, biomass, root-shoot ratio), photosynthetic pigment content (chlorophyll a, chlorophyll b, total chlorophyll, carotenoid), relative conductivity, MDA content, osmotic adjustment substance content (proline, soluble sugar), superoxide dismutase (SOD) and peroxidase (POD) were measured under various treatments. Result: 1) The inhibition effect of 0.7% CaCl₂ stress on the growth of Sabina chinensis seedlings was greater than that of 0.7% NaCl stress. Under 0.7% CaCl₂ stress, other physiological indexes (chlorophyll a, chlorophyll b, total chlorophyll, MDA, proline content, relative conductivity, POD, SOD activity) were higher than those under NaCl stress except that the content of soluble sugar and carotenoid was lower than that under NaCl stress. 2) Under two kinds of salt stress, fulvic acid potassium increased height growth, ground diameter growth and biomass, increased chlorophyll a, chlorophyll b, total chlorophyll and carotenoid content, decreased relative electrical conductivity and MDA content, and showed a low-high-low trend in SOD and POD activity, prominence acid and soluble sugar content. Under 0.50% FA-K, the seedling growth under the two salt stresses was close to the control. 3) Compared with 0.7% NaCl stress, fulvic acid potassium showed better mitigation effect on 0.7% CaCl₂ stress. Conclusion: The result indicated that high salt significantly inhibited the growth and survival of Sabina chinensis, and the inhibition effect of 0.7% CaCl₂ was stronger than that of 0.7% NaCl. The stress of NaCl and CaCl₂ could be effectively mitigated by fulvic acid potassium, and 0.50% of fulvic acid potassium was most effective.

Objective: This study aims to explore the dominant environmental factors affecting the distribution of C. mollissima and simulate the potential distribution areas of C. mollissima under different climatic conditions, which would provide a theoretical basis for the conservation and introduction of C. mollissima germplasm resources. Method: Based on geographical information on 472 distribution points of existing C. mollissima populations and 21 environmental variables, an ensemble species distribution model was used to simulate the potential suitable distribution areas of C. mollissima, and the accuracy of the model was evaluated by the value of AUC and TSS. The ensemble model was used to speculate the distribution of suitable areas for C. mollissima and their change trends in the Last Glacial Maximum, Mid-Holocene, Current, 2030 and 2050. Result: 1) Among the 10 models, RF, GBM, MARES and GAM displayed the best and stable performance in prediction accuracy, and AUC and TSS values of the ensemble model were 0.974 and 0.816, respectively, indicating a high accuracy. 2) The main environmental factors affecting the geographical distribution of C. mollissima were the minimum temperature of the coldest month, altitude, precipitation of the wettest quarter, temperature annual range and precipitation of wettest month, and their cumulative contribution was 89.79%. 3) Under the current climate conditions, the potential growing areas of C. mollissima in China were widely distributed, and since the Last Glacial Maximum, the growing areas of C. mollissima have been expanding to higher latitudes, and the warmer the climate, the faster the expansion. The overall suitability of C. mollissima has been decreasing, more prominently in the south and less in the north, and the total area of high suitability zones has been gradually decreasing. Conclusion: The geographical distribution of C. mollissima is influenced by both climatic and topographic factors, among which the temperature makes the greatest contribution and altitude also plays a crucial role. Under the current climate, C. mollissima have a wide range of suitable areas in China, and it is recommended that planting and germplasm conservation should be carried out in highly suitable areas, and migration to higher latitudes should be appropriate when climate conditions are unfavorable for C. mollissima growth in the future, so as to reduce the losses caused by climate change.

Objective: In this study, species-specific KASP primers were developed to identify the interspecific hybrids from Salix suchowensis and S. triandra, which would lay a foundation for the authenticity identification of breeding new germplasm of fast growth and insect resistance in willow. Methods: Whole genome SNPs were analyzed for selecting species-specific SNPs, and designing KASP primers based on the resequencing data of S. suchowensis and S. triandra. SeqHunter2 was used to detect the versatility of the designed primers in S. suchowensis, and natural population materials from S. suchowensis and S. triandra were used to test validation of the primers for species-specific and versatility identification by PCR amplification test. The selected species-specific KASP primers were used for the authentication identify of their hybrids. Results: The all resequencing data of S. suchowensis and S. triandra were aligned to the S. triandra genome, and a total of 6 598 144 SNPs were detected over the whole genome. After filtering by a house perl script, 674 144 homozygous SNP sites were identified in S. suchowensis, which were homozygous mutation sites with S. triandra. One hundred SNPs were randomly selected from each chromosome for KASP primer design based on the genome sequence of S. triandra and 750 primer pairs were successful designed among the 1 900 randomly selected SNP sites. SeqHunter2 detection revealed that 11 primers were versatile in S. suchowensis and S. triandra from the 38 primer pairs randomly selected from different chromosomes. Ten synthesized versatile primer pairs were used for for intra species conservation and inter species difference detection, and four of them could get an obvious clustering in S. suchowensis, S. triandra and its hybrids. Primer pairs of Stri08_82809, Stri14_11602, Stri14_12274 and Stri17_10731 amplified homozygous site of G/G, T/T, A/A and T/T respectively in the population of S. suchowensis, and homozygous site of A/A, C/C, G/G and C/C respectively in the population of S. triandra. For the hybrids identification, the real interspecific hybrids amplified heterozygous sites of G/A, T/C, A/G and T/C respectively. The above four primers were used to identify the inter-specific hybrids of S. suchowensis × S. triandra, the result showed that 29 out of 31 hybrids were real interspecific hybrids because they could amplify heterozygous sites which were inherited from the two parents used for hybridization. The remained two hybrids were none inter-specific because they could only amplify homozygous sites in the four SNPs sites that were identical to the female parent, indicating that these two offspring were descendants contaminated with pollen from S. suchowensis. Conclusion: In this study, four groups of species-specific KASP markers have been obtained for identifying conservative between S. suchowensis and S. triandra. The developed KASP primers can identify the authority of inter-specific hybrids from the cross or backcross breeding of S. suchowensis and S. triandra, which would provide technological support for the insect resistance germplasm innovation by inter-specific hybridization between S. suchowensis and S. triandra.

Objective: BBX (B-box) is an important subfamily of zinc finger structural protein transcription factor family, which plays an important regulatory role in plant growth and development, plant signal transduction and stress response. Cloning and functional analysis of the BBX24 gene in Chimonanthus praecox (wintersweet) may help to enrich the understanding of the BBX gene family in plants, and provide theoretical basis for the stress-resistant regulation mechanism of wintersweet. Method: Based on the cDNA sequence of CpBBX24 gene in the wintersweet transcriptome database, we obtained the CpBBX24 gene and analyzed the sequence characteristics and evolutionary tree by DNAStar and MEGA. The expressions of CpBBX24 in different tissues and flowering stages, and the changes of CpBBX24 gene expression under ABA, MeJA, drought, high salt, high temperature and low temperature treatments were analyzed using qRT-PCR. At the same time, the Gateway technology was used to construct plant overexpression vectors, and Arabidopsis was transformed by floral dipping method. Homozygous lines of the T3 generation were used for phenotype observation and abiotic stress tolerance analysis. Result: The cDNA sequence of CpBBX24 is 1374 bp, containing 729 bp open reading frame (ORF), encoding 242 amino acids with molecular weight was 26.54 kD and isoelectric point 4.93. Sequence analysis showed that CpBBX24 protein had two tandem B-box domains at the N-terminus, and its C-terminus did not contain a CCT domain. The results showed that the CpBBX24 gene expressed in the roots, stems, cotyledons, young leaves, mature leaves, and flower tissues such as outer petals, inner petals, pistils and stamens, and the expression level was highest in cotyledons. In different flowering stages, the expression of CpBBX24 fluctuated, and the expression level was the highest in the senescent stage. ABA, MeJA, drought, High salt, high temperature and low temperature could induce the expression of CpBBX24 gene, and the expression trends were different. Under the stress of PEG (30% PEG-6000), high salt (300 mmol·L^?1 NaCl), hot (42 °C) and cold (4 °C) stress, the overall growth state of the transgenic Arabidopsis plants was better than that of the wild type. The values of relative conductivity and malondialdehyde concentration were significantly lower than those of the wild type, indicating that the overexpression of CpBBX24 gene enhanced the drought, high-salt, high-temperature and low-temperature stress tolerance of Arabidopsis. Conclusion: The expression of CpBBX24 was induced by ABA, MeJA, drought, High salt, high temperature and low temperature stress, indicating that it may be involved in the regulation of adversity stress tolerance in wintersweet. The overexpression of CpBBX24 enhanced the stress tolerance of Arabidopsis to drought, high salt, high temperature and low temperature. These results indicated that CpBBX24 gene plays an important role in response to stresses such as drought, high salinity, low temperature and high temperature.

Objective: This study aims to provide a scientific basis and reference for the targeted fire management and rational formulation of fire prevention and control policies in the study area by comparing and analyzing the differential changes in the occurrence patterns of lightning fires and human-caused fires in Daxing’an Mountains, Heilongjiang Province. Method: Based on the forest fire data in the study area between 1966 and 2021, lightning fires and human-caused fires were categorized by fire cause, and the differences in the occurrence of lightning fires and human-caused fires at different time scales, changes in patterns and trends in the fire season were compared and analyzed by means of ANOVA and linear fitting. Result: A total of 1 887 forest fires occurred in the study area between 1966 and 2021, of which 932 were lightning fires and 503 were human-caused fires, accounting for 49.39% and 26.66% respectively. There were significant differences between lightning fires and human-caused fires on different time scales such as year, month and period of occurrence. The number of lightning fires in the study area showed a fluctuating increase, while the number of human-caused fires showed a fluctuating decrease, especially after 1987, the number of lightning fires in the study area gradually increased compared to that of human-caused fires, but the overall change in the total number of forest fires in the study area was not significant. In terms of fire area, the overall area of lightning fires had an increasing trend in the study area, while the area of human-caused fires and total forest fire had a decreasing trend. The lightning fires in the study area mainly occurred in June and July, while human-caused fires occurred mostly in April and May. There was a trend of significant increase in the number of lightning fires during summer forest fire prevention period, but the change in the area of lightning fires was not significant. However, there were significant decreases in the number and area of human-caused fires during spring forest fire prevention period. From the perspective of occurrence time, the period of high incidence of human-caused fires in the study area was from 10:00 to 15:00, while the period of high incidence of lightning fires was from 12:00 to 17:00. The difference between lightning fires and human-caused fires at different time scales resulted in a change in the fire season in the study area, with the lightning fire season showing a delayed expansion, the human-caused fire season showing a gradual shortening, and the total forest fire season showing a contraction and shortening. Conclusion: Due to climate change and fire prevention policies, there are obvious differences in the occurrence patterns between lightning fires and human-caused fires in Daxing’an Mountains, Heilongjiang Province. Targeted fire prevention and control efforts based on the occurrence characteristics and changing trends of different fire types are a necessary prerequisite for effectively reducing forest fire risks in the study area.

Objective: The bearing performance of Pseudotsuga menziesii and SPF(spruce-pine-fir) parallel chord wood trusses under different web angles was compared to explore the influence of web angles and structural materials on the bearing performance of wood trusses, providing theoretical basis for the structural design of parallel chord wood trusses. Method: Using Smsolver structural mechanics solver, the internal force variation and deformation of each member of parallel chord wooden truss were quantitatively analyzed with bearing capacity and stability as checking indexes, and the upper and lower critical values and optimal web angles values of parallel chord wooden truss were obtained. ABAQUS finite element software was used to analyze and verify the finite element models of Pseudotsuga menziesii and SPF parallel chord wooden trusses with three different web angles. The internal force variation rule of the parallel chord wood trusses with different base materials under different web angles was obtained, and the possible failure mode and stress mechanism were determined. On this basis, with Pseudotsuga menziesii and SPF as base material, respectively, making three web angle parallel chord wood truss, bearing capacity for bending static test, explore parallel chord wood truss of the ultimate load, stress distribution and the main failure mode, and is contrasted with the results of finite element simulation, to verify the exactness of the parallel chord wood truss finite element model analysis and applicability. Result: 1) The optimal web angle of the warren type parallel chord wooden trusses was 47°, the critical value of the lower limit web angle was 34°, and the upper limit web angle was 60°. 2) The ultimate load range of Pseudotsuga menziesii parallel chord wooden trusses was 26.53?40.83 kN and the mid-span deflection range was 30.57?31.01 mm. The ultimate load range of the SPF parallel chord wooden trusses was 23.48?34.16 kN and the mid-span deflection range was 31.85?32.05 mm. 3) The ultimate load of Pseudotsuga menziesii and SPF parallel chord wooden trusses with 34°, 47° and 60° web angle was 26.53 and 23.48 kN, 35.10 and 30.06 kN, 40.83 and 34.16 kN, respectively. The corresponding mid-span deflections were 31.85 and 31.01 mm, 30.72 and 32.05 mm, 30.57 and 31.97 mm, respectively. 4) The failure mode of Pseudotsuga menziesii parallel chord wooden trusses was mainly manifested as the crack in the web member near the truss support and the toothed plate pulling out at the truss end or the load applying point, while the failure mode of SPF parallel chord wooden truss was mainly manifested as the toothed plate pulling out at the truss end and the load applying point. 5) Through ABAQUS finite element simulation and experimental verification, it was found that the chord member axial force at the middle part of the two truss spans is the largest, decreasing gradually on both sides, while the web member force at the middle part of the truss spans is the smallest, increasing gradually on both sides, The chord member axial force was larger than the chord axial force. Conclusion: The bearing capacity of Pseudotsuga menziesii parallel chord wooden trusses is better than SPF parallel chord wooden trusses. The bearing capacity of the parallel chord wood truss increases with the increase of the web angle. Comprehensive analysis shows that the weak points of the two parallel chord wooden trusses are the toothed plate joints at the end of the truss and the loading point. The ABAQUS finite element model can effectively reflect the stress distribution and deformation trend of the whole structure.

Enhancing forest carbon sink is an effective way to slow down the rising atmospheric carbon dioxide (CO₂) concentration, contributing to China’s national strategic goals for carbon neutrality. This review summarizes major research progresses in quantification of dynamic changes in forest carbon storage and sink, and explores the ways of their potential capacity enhancement. According to the China’s national forest resources inventory, the carbon storage of forests has increased by an average annual rate of 0.152 Pg in the past five years. The carbon sink of China’s terrestrial ecosystems during the 2000s—2010s was about 229.7 Tg·a^?1, of which forests (here only referring to arbor forests) increased by about 150.6 Tg·a^?1, accounting for about 65.6% of the total terrestrial vegetation carbon sink. Over the past 70 years, China’s forests have turned from carbon source to rising carbon sink. The potential capacity of forest biomass carbon storage and sink are projected with the two scenarios. Without increasing afforestation, the existing forest biomass carbon sink will be likely to decline after 2030 compared with the base line of 2020, while it may continue to increase during 2030 to 2050 with increasing afforestation. Under the global change, climate change and climate-driven disturbance risks (such as extreme droughts and heatwaves, forest fires, pests and disease outbreaks) may fundamentally jeopardize forest carbon sinks. Therefore, in order to maintain and enhance the carbon sink capacity of China’s forests, it is necessary to scientifically optimize national forest management schemes in terms of carbon pool preservation of the existing natural forests, carbon sink enhancement either through rational management of the existing forests or through afforestation expansion, and carbon sink transfer from the living forests to the forest product pool for simultaneously maintaining sustainable improvements of both forest carbon stock and sink. Forest soils should be given due attention as a slowly increasing sink potential from a long-term perspective. Under the framework of forest mitigation and adaptation to climate change, future research priorities in forest carbon sequestration include identification of suitable site and tree species for land greening under a changing environment, forest adaptive management regime for carbon sequestration enhancement, insight into the mechanisms underlying forest soil carbon sequestration, and optimizing tempo-spatial patterns of synergistic enhancements in forest biomass carbon stock and sink capacity. In addition, there is a need to accurately assess the potential capacity of forest carbon sink contributing to achieving China’s carbon neutrality goal with the defined timeline and roadmap of the deliverables.

Primary forest refers to the forest formed by the natural succession of native tree species, without obvious traces of human interference, and the ecological process has not been significantly affected. With complex structure and ecological functions, it is the most stable carbon storage and resource bank in nature, and plays an important role in global climate regulation and human survival and development. To clarify and standardize the concept and monitoring method of primary forest in the research field is conducive to the inventory, protection, and monitoring of primary forest resources in the world. Based on reviewing the concept of primary forest at home and abroad, this study summarized the characteristics of primary forest, analyzed the status quo of inventory and monitoring of primary forest resources at home and abroad, and summarized the important ecological functions of primary forest: 1) Carbon neutrality, carbon source, and carbon pool hypothesis about the existence of carbon sequestration capacity of primary forest; 2) Primary forest has better hydrological regulation function than other forests; 3) It is a species gene bank with outstanding biodiversity conservation functions. Based on the existing problems in the concept and monitoring of primary forests, the paper puts forward some suggestions for future research: to classify primary forests separately in forest resource inventory; the ecological function of primary forests should be studied, carbon sequestration potential of primary forest and soil respiration should be studied; Increase studies on the hydrologic regulation capacity of primary forests and explore the role of primary forests in mitigating global climate change; explore the biodiversity conservation functions of primary forests to reduce global biodiversity loss.