气候变化领域集成服务门户(CCPortal): Detecting dynamics and variations of crown asymmetry induced by natural gaps in a temperate secondary forest using terrestrial laser scanning

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DOI	10.1016/j.foreco.2020.118289
	Detecting dynamics and variations of crown asymmetry induced by natural gaps in a temperate secondary forest using terrestrial laser scanning
	Lu D.; Zhu J.; Wu D.; Chen Q.; Yu Y.; Wang J.; Zhu C.; Liu H.; Gao T.; Wang G.G.
发表日期	2020
ISSN	0378-1127
卷号	473
英文摘要	Gap formation and closure play important roles in forest succession. Most studies focused on regeneration within gaps, but less is known about the growth dynamics of canopy trees surrounding the gaps (i.e., gap border trees), which limits our understanding of the gap-filling process. In this study, terrestrial laser scanning (TLS) was used to quantify the crown asymmetry of six canopy tree species with different wood densities among young gaps (15a), old gaps (32a), and closed forest stands (CK). The size of expanded gaps ranged from 166.8 to 408.1 m2 with an average of 271.5 m2. Each gap border tree was separated into two parts, i.e., one part facing the gap (FG) and the other facing the forest interior (FF). The ratios (FG/FF) of crown length, crown projected area, and crown volume of these two parts were calculated to represent one-, two-, and three-dimensional crown asymmetry, respectively. We found that 90% gap border trees had asymmetric crown toward gaps with an average ratio of 1.58. For trees in the closed forest stands, although crown asymmetry occurred randomly in different directions and had a large variation, the average ratio was close to 1.00. However, the gap age and the location of gap border tree (i.e., north, east, south, and west of the gap) did not show significant influences on the crown asymmetry because differences of crown asymmetry probably disappeared after the long period of gap formation. The crown asymmetry exhibited inter-specific variations and was positively correlated with wood density, which indicated that tree species with a higher wood density such as Acer mono (0.61 g cm−3) could support a more asymmetric crown and have a higher asymmetric crown threshold than others such as Juglans mandshurica (0.45 g cm−3). Crown asymmetry had similar results among different dimensions. Our findings indicated that the general crown asymmetry of gap border trees might increase snapping and uprooting risks during wind and snow disturbances. Although gap-based silviculture is widely applied in forest management, additional practices such as thinning or selective harvesting should be considered to create more space and alleviate an asymmetric crown induced by gap formation. © 2020 Elsevier B.V.
关键词	Facings Hardwoods Laser applications Steel beams and girders Surveying instruments Crown asymmetry Forest interiors Forest succession Gap-filling process Growth dynamics Secondary forests Selective harvesting Terrestrial laser scanning Reforestation asymmetry canopy architecture detection method gap dynamics induced response laser method regeneration secondary forest temperate forest timber harvesting Asymmetry Facings Formation Hardwoods Reforestation Trees Variations Wood Density Acer mono Juglans mandshurica
语种	英语
来源机构	Forest Ecology and Management
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/132705
推荐引用方式 GB/T 7714	Lu D.,Zhu J.,Wu D.,et al. Detecting dynamics and variations of crown asymmetry induced by natural gaps in a temperate secondary forest using terrestrial laser scanning[J]. Forest Ecology and Management,2020,473.
APA	Lu D..,Zhu J..,Wu D..,Chen Q..,Yu Y..,...&Wang G.G..(2020).Detecting dynamics and variations of crown asymmetry induced by natural gaps in a temperate secondary forest using terrestrial laser scanning.,473.
MLA	Lu D.,et al."Detecting dynamics and variations of crown asymmetry induced by natural gaps in a temperate secondary forest using terrestrial laser scanning".473(2020).