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Effects of Structure-Based Forest Management on Stand Space Structure and Its Stability of Mixed Oak-Pine Forest     Pan Wan,Wenzhen Liu,Ruihong Liu,Peng Wang,Hongxiang Wang,Gangying Hui Scientia Silvae Sinicae   2020,56(4 ):35 -45. DOI:10.11707/j.1001-7488.20200404 Abstract  （276） HTML （15） PDF（pc） （3798KB）（403） Save Objective: The univariate and bivariate distribution characteristics of stand space structure were studied, and the stand stability in the mixed oak-pine forest under structure-based forest management was also analyzed, in order to provide the scientific basis for the implementation and evaluation of structure-based forest management in Quercus aliena var. acuteserrata mixed forest. Methods: The natural mixed oak-pine forest in Daganzigou, Baihua forest Farm, Xiaolongshan nature reserve, Gansu Province, as object was studied. In 2012, one 50 m×50 m, two 30 m×30 m and three 20 m×20 m fixed plots were established, the total station (TOPCON-GIS-602AF) was used to locate each tree with a diameter of more than 5 cm in all plots and investigate its species, diameter, height and crown. After those, one 50 m×50 m and two 30 m×30 m plots were used for structure-based forest management, and others plots were used for without any management as control. In 2017, the characteristics of stand spatial structure in managed and unmanaged plots were compared by the stand spatial structure parameters, such as uniform angle, dominance and mingling. The nine indicators of mixed oak-pine forest were selected as the parameters to construct the stability evaluation system, and stand stability was evaluated by the new rule of π value method of optimal stand state. Results: 1) The stand trees of managed plots before operation were close to aggregated distribution, and the stand trees of managed plots after five years of operation were randomly distributed, however, the stand trees of unmanaged plots were always presented an aggregated distribution. Simultaneously, the proportion of highly mixed by species in managed forest after five years of operation was increased by 10.4% compared with the managed forest before operation, the proportion of highly mixed by species in unmanaged forest grown for five years was increased by 5.5% compared with the unmanaged forest before five years. 2) Bivariate distribution of spatial structural parameters showed that the proportion of micro-structure that was the four or three neighbours were of different species to the reference tree and had a random distribution pattern in managed stand was higher than unmanaged stand, and the proportion of micro-structure that was the reference tree was dominant and surrounded by different species in managed stand was higher than unmanaged stand, on the whole, the proportion of micro-structure that was dominant and four neighbours had a random distribution pattern was not obviously different between unmanaged and managed stand. 3) Unit circle analysis of stand status showed that the ω value of managed forest after five years of operation was increased 27.09% compared with the managed forest before operating, the stand status was from poor to good, while theωvalue of unmanaged forest grown for five years was increased 13.24%, but the stand status was always poor. Conclusion: The trees of structure-based managed stand has a reasonable distribution and highly mingling, and dominant wood in highly mixed. Meanwhile, stand status of structure-based forest managed presented at a good level, which shows higher stand stability. Table and Figures丨 Reference丨 Related Articles丨 Metrics

Research Progress on Effects of Forest Fire Disturbance on Carbon Pool of Forest Ecosystem     Haiqing Hu,Bizhen Luo,Sisheng Luo,Shujing Wei,Zhenshi Wang,Xiaochuan Li,Fei Liu Scientia Silvae Sinicae   2020,56(4 ):160 -169. DOI:10.11707/j.1001-7488.20200418 Abstract  （429） HTML （22） PDF（pc） （1456KB）（320） Save Forest ecosystem is an important carbon pool and plays an important role in mitigating climate warming. As a discontinuous ecological factor of forest,forest fire disturbance is the driving factor of biogeochemical cycle,which significantly changes the structure and function of the ecosystem,nutrient cycle and energy transfer,and causes the change of carbon pool and carbon distribution pattern in forest ecosystem,and in turn affects the process of forest succession and carbon sequestration capacity. This paper reviews the domestic and abroad research method on the impact of forest fire disturbance on forest carbon pool,and focuses on the direct and indirect effects of forest fire disturbance on forest carbon pool. The direct impact is mainly the direct carbon loss of forest ecosystem,while the indirect impact is mainly through forest ecosystem net primary productivity and soil respiration changes to affect the carbon cycle and carbon balance of forest ecosystems. The influence of forest fire disturbance on vegetation carbon pool,litter carbon pool and soil organic carbon pool are respectively clarified. The forest fire disturbance affects vegetation carbon pool and nutrient turnover by directly changing vegetation coverage,and ultimately affects vegetation fixation to carbon and the transfer of carbon from vegetation to soil leads to redistribution between different carbon pools. In terms of the effects of forest fire disturbance on the litter carbon pool of ecosystem,the main researches are mainly the change of litter production under different forest fire intensity and environmental gradient after forest fire disturbance. The influence of forest fire disturbance on soil organic carbon pool can be studied from small scale and large scale. Generally,in the small scale,the change of topographic conditions may be the main reason that affects the vertical distribution of soil organic carbon pool. At relatively large regional scales,the interactions of climate,soil texture,topography,vegetation,and human activities and management levels can affect the spatial migration and morphological transformation of soil organic carbon pools,which leads to the difference of soil organic carbon pools in different regions. On this basis,this paper points out the existing problems in the study. Finally,the quantitative research on the influence of forest fire disturbance on the carbon pool of forest ecosystem is put forward:1) Futher research on the effect mechanism of forest fire disturbance on the carbon pool circulation of forest ecosystem. 2) Strengthen the systematic study of "vegetation-soil-water-microbe-climate". 3) Improve the quantification of forest fires in the forest ecosystem by the forest fire disturbance at different time and space scales. 4) Futher discussion in-depth of the interaction between forest fire disturbance and carbon in forest ecosystems and its impact mechanism. Table and Figures丨 Reference丨 Related Articles丨 Metrics

Research Progress on Total Synthesis of Precursor Components of Sex Pheromones from Six of Pine Caterpillar Species in China     Fu Liu,Zhongwei Yuan,Xiangbo Kong,Sufang Zhang,Zhen Zhang,Zhifeng Guo,Zhenlin Li,Yanhui Song,Yibin Zhou Scientia Silvae Sinicae   2020,56(4 ):170 -180. DOI:10.11707/j.1001-7488.20200419 Abstract  （248） HTML （3） PDF（pc） （1501KB）（113） Save There are six species of pine caterpillars in China,including pine caterpillars include Dendrolimus punctatus,D. superans,D. tabulaeformis,D. houi,D. spectabilis and D. kikuchii,and all the insects are serious pests of pine forests in China. Pine caterpillars have a strong reproductive capacity. When the pests break out,the all leaves of pines are eaten up quickly,which seriously hinders the growth of trees and even causes the trees to die. Furthermore,the pine caterpillars'infestation cause pines to decline,which can lead to the invasion of stem borers. Therefore,the control of pine caterpillars has always been an important research direction of forest entomologists in China. It is an important part of the comprehensive management of pine caterpillars to find an effective population monitoring method. Sex pheromone is an important means for the comprehensive management of pine caterpillars for its strong specificity and convenient application. Sex pheromone attractants can be used not only to monitor the occurrence period and population dynamics of pine caterpillars,but also to control the population number and prevalence by interfering with their mating. The active ingredients of sex pheromones in the 6 species of pine caterpillars could be divided into two main categories. The derivative of (Z,E)-5,7-dodecadien-1-ol and the derivative of (E,Z)-5,7-dodecadien-1-ol. Their precursors are the corresponding alcohols. In this paper,the synthesis methods of these two precursor compounds were summarized. The total synthesis of (Z,E)-5,7-dodecadien-1-ol could be roughly classified into three different synthetic ways. Route one,the Wittig reaction between aldehydes and phosphoranes; Route two,coupling reaction of E type iodinated alkene with unsaturated hydrocarbons; Other paths of reactions,including anti-Markovnikov addition of substituted olefins; rearrangement of thexylalkenyllalkynylboranes,and coupling reactions of organometallic reagents. In contrast,(E,Z)-5,7-dodecadien-1-ol could be synthesized by two ways. Route one,the Wittig reaction between α,β-unsaturated aldehydes and phosphoranes; Route two,coupling reaction of E type iodinated enol with alkynes. At present,the demand for sex pheromone of pine caterpillars is increasing day by day,and the design and optimization of its synthesis methods have become an important task. Consequently,this review will provide important reference for the researchers who carry out the similar research in China. Table and Figures丨 Reference丨 Related Articles丨 Metrics

Morphological Characteristics and Occurrence Status of the Dangerous Pest, Acanthotomicus suncei (Coleoptera: Curculionidae: Scolytinae)     Lei Gao,Jianguo Wang,Zhangxun Wang,You Li,Ruiting Ju Scientia Silvae Sinicae   2020,56(3 ):193 -198. DOI:10.11707/j.1001-7488.20200320 Abstract  （531） HTML （10） PDF（pc） （3184KB）（152） Save Objective: Liquidambar styraciflua, north American sweetgum tree is a new important exotic ornamental foliage tree that is widely used in urban areas of eastern China. To provide information for prevention and control of a new bark beetle pest, Acanthotomicus suncei, which damages north American sweetgum, we described morphological characteristics of the bark beetle and its biological characteristics as well as its occurrence status in Shanghai and adjacent regions. Method: We collected information of its biology and occurrence through field investigation. The proventricule and male genitalia of the beetle specimens were collected from host trees in the field. A stereo microscope was used to observe the morphological characteristics. The difference in the morphological characteristics from all known Acanthotomicus species in China were compared. Result: A. suncei has distinct identification characteristics. The placement of four elytral declivital spines arise on interstriae 2, 4, 6, and 8. Lateral tibiae of both foreleg and midleg have 4 dentations respectively, and the declivital spines of females are smaller than males. The differences in morphological characteristics from the three known Acanthotomicus species in China were significant. The length of A. perexiguus is less than 2 mm, with 3 pairs of declivital spines. A. spinosus carries 8 pairs of declivital spines while the length is similar with A. suncei. The beetle has 2 to 3 generations per year in Shanghai. The larvae feed on cambium and phloem in the trunk, causing rapid death of the host trees. It was found that 14 planting sites of American sweetgum were infested by A. suncei and more than 30 000 trees died from the beetle feeding under nurseries, parks or landscapes in Shanghai and adjacent regions. Meanwhile, L. formosana trees in some regions were also found to die after being attacked by A. suncei. Conclusion: The phenomenon of A. suncei attacking healthy sweetgum trees is reported for the first within the genus Acanthotomicus. A. suncei is an oligophagous insect, and the host range is limited to the genus Liquidambar. It's unlikely to harm other host plants. A. suncei prefers to American sweetgum, which may be related to the principle of physiological equivalence of the host plant. A. suncei is a serious threat to the introduction and cultivation of north America sweetgum. We recommend that monitoring should be carried out as soon as possible in planting areas of north American sweetgum trees. Once the infestation of A. suncei is found, the infested plants should be removed immediately, and isolation zones should be set up to protect healthy plants, which could prevent the spread of the pest. At the same time, it is necessary to strengthen the research on risk prediction, early warning, prevention and control method in the suitable distribution area of this pest, so as to lay the foundation for the final control of the pest. Table and Figures丨 Reference丨 Related Articles丨 Metrics