Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Forestry submitted time 2024-02-21 Cooperative journals: 《干旱区科学》
Abstract： Tree plantation and forest restoration are the major strategies for enhancing terrestrial carbon sequestration and mitigating climate change. The Grain for Green Project in China has positively impacted global carbon sequestration and the trend towards fragmentation of plantation forests. Limited studies have been conducted on changes in plantation biomass and stand structure caused by fragmentation, and the effect of fragmentation on the carbon storage of plantation forests remains unclear. This study evaluated the differences between carbon storage and stand structure in black locust forests in fragmented and continuous landscape in the Ansai District, China and discussed the effects of ecological significance of four landscape indices on carbon storage and tree density. We used structural equation modelling to explore the direct and indirect effects of fragmentation, edge, abiotic factors, and stand structure on above-ground carbon storage. Diameter at breast height (DBH) in fragmented forests was 53.3% thicker, tree density was 40.9% lower, and carbon storage was 49.8% higher than those in continuous forests; for all given DBH>10 cm, the trees in fragmented forests were shorter than those in continuous forests. The patch area had a negative impact on carbon storage, i.e., the higher the degree of fragmentation, the lower the density of the tree; and fragmentation and distance to edge (DTE) directly increased canopy coverage. However, canopy coverage directly decreased carbon storage, and fragmentation directly increased carbon storage and tree density. In non-commercial forests, fragmentation reduces the carbon storage potential of plantation, and the influence of patch area, edge, and patchy connection on plantation should be considered when follow-up trees are planted and for the plantation management. Thus, expanding the area of plantation patches, repairing the edges of complex-shaped patches, enhancing the connectivity of similar patches, and applying nutrients to plantation forests at regular intervals are recommended in fragmented areas of the Loess Plateau.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Forestry submitted time 2022-07-18 Cooperative journals: 《干旱区科学》
Abstract：The study of the heterogeneity of soil enzyme activities at different sampling locations in canopy gaps will help understand the influence mechanism of canopy gaps on soil ecological processes. In this paper, we analyzed the spatiotemporal variation of soil enzyme activities and soil physicochemical properties at different sampling locations (closed canopy, expanded edge, canopy edge, gap center) in different sampling time (December, February, April, June, August, and October) on the northern slope of the Tianshan Mountains, Northwest China. The results showed that soil catalase, cellulase, sucrase, and acid phosphatase activities were relatively high from June to October and low from December to April, and most of soil enzyme activities were higher at closed canopy than at gap center. Soil urease activity was high during DecemberFebruary. The soil temperature reached the highest value during JuneAugust and was relatively high at gap center in October, December, and February. Soil water content was significantly higher in December and April than in other months. Soil bulk density was higher at gap center than at closed canopy in December. Soil pH and soil electrical conductivity in most months were higher at closed canopy than at gap center. Soil organic carbon, soil total nitrogen, and soil total phosphorus were generally higher at gap center than at closed canopy. Furthermore, sampling time played a leading role in the dynamic change of soil enzyme activity. The key factors affecting soil enzyme activity were soil temperature and soil water content, which were governed by canopy gaps. These results provide important support for further understanding the influence mechanism of forest ecosystem management and conservation on the Tianshan Mountains.
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Forestry submitted time 2020-01-13
Abstract： " This paper introduced the origin, formation and development of the discipline of chemical processing engineering of forest products by analyzing the effect of the fundamental disciplines of chemistry, chemical engineering and biology on the scientific theory and technology development in the area of chemical utilization of forestry plant resources in terms of the basic concepts of discipline science in the past more than 100 years. On these basis, we proposed the idea of the modern discipline of chemical processing engineering of forest products, and elucidated that this modern discipline is concerned with a scientific system of theories and technologies on utilization of forest plant resources by two main approaches of chemistry and bio-chemistry aiming to synthesize and prepare biomass-based energy source, chemicals and functional materials. Finally, we discussed the scientific and technological challenges that the modern discipline of chemical processing engineering of forest products is predominantly faced with in the future.
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