The effects of selective logging on forest structure and tree species composition in a Central African forest: implications for management of conservation areas
The effects of selective logging on forest structure and tree species composition in a Central African forest: implications for management of conservation areas
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DOI：
10.1016/s0378-1127(03)00107-5
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发表时间：
2003-09-15
影响因子：
3.7
通讯作者：
Ashton, PMS
中科院分区：
文献类型：
--
作者：
Hall, JS;Harris, DJ;Ashton, PMS
中部非洲的森林因其壮观的野生动物而享誉世界，并蕴藏着丰富的优质木材。由于管理不善和将西非大片森林转为农业生产，中部非洲森林面临着越来越大的采伐压力。在喀麦隆、中非共和国和刚果共和国这三个国家的地区，广泛应用的综合保护和发展模式将生物多样性保护和木材生产的双重管理目标归于同一地区。许多在该地区工作的自然资源保护者认为，高度选择性的木材开采是实现这些目标的最佳管理方案。传统观点认为，如果选择性采伐不能充分更新Entandrophagma spp.，伐木者将在开采完森林后离开该地区。对未采伐、6个月和18年后采伐的森林进行比较表明，高选择性、高等级采伐的持久影响。不同处理间树种组成和多样性差异不大，但采伐18年后未采伐林中幼树和乔木的树干密度均显著高于采样林。有证据表明，主要木材树种--圆筒花木和圆筒花木的招募不足，不足以证明继续采掘木材是合理的。数据表明，由于树冠干扰不足，树冠优势从不耐荫树种转变为树荫强树种。尽管如此，在选择性地移除非洲红木之后，仍然保留了大量其他优质木材物种，这些森林在Entandrophagma spp根除后很长一段时间内仍将对伐木者具有吸引力。管理木材生产和养护林区的更好办法是以增加树种选择和树冠干扰为基础的适应性管理办法。不应记录以保护封禁森林专有物种为目标的区域。(C)2003 Elsevier Science B.V.保留所有权利。
The forests of Central Africa enjoy world-wide recognition for their spectacular wildlife and also harbor an abundance of high quality timber. With mismanagement and the conversion of large tracts of West African forest to agricultural production, Central African forests are experiencing increased harvesting pressures. This is particularly true for species of African mahogany (Entandrophragma spp.).In the tri-national region of Cameroon, Central African Republic, and Republic of Congo, a widely applied version of the Integrated Conservation and Development Model attributes the dual management objectives of biodiversity conservation and timber production to the same zones. Many conservationists working in the region believe that highly selective timber extraction is the best management scenario to meet these objectives. Conventional wisdom holds that if selective logging does not adequately regenerate Entandrophragma spp., loggers will quit the region after having mined the forest.A comparison between unlogged, 6-month and 18-year post-harvest forest stands indicates lasting effects of highly selective, high grade logging. While there was little difference in tree species composition and diversity between treatments, stem densities of both saplings and trees in unlogged forest were significantly higher than those in forest sampled 18 years after logging. Evidence suggests inadequate recruitment of Entandrophragma cylindricum and E. utile, the principal timber species, to justify continued timber extraction. Data indicate a significant shift in canopy dominance from shade intolerant to shade beating species due to insufficient canopy disturbance. Nevertheless, an abundance of other top quality timber species remains after selective removal of African mahogany and these forests will remain attractive to loggers long after the elimination of Entandrophragma spp. A better approach to manage timber zones for timber production and conservation would be an adaptive management approach based on increased species selection and canopy disturbance. Zones targeting the conservation of closed forest obligate species should not be logged. (C) 2003 Elsevier Science B.V. All rights reserved.