分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2018-02-28 合作期刊: 《干旱区科学》
摘要：In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine (Pinus tabuliformis). This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east- and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78 (±0.85) and 1.06 (±1.15) m, and the average diameters at breast height (DBH) were 3.21 (±1.38) and 2.91 (±1.38) cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east- and north-facing slopes, average heights of recruits reached 2.00 (±1.14) and 2.24 (±1.20) m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has the potential to be an effective approach for establishing multifunctional forest.
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