Effects of "selective" timber extraction on rain forest structure and composition and some consequences for frugivores and folivores
Effects of "selective" timber extraction on rain forest structure and composition and some consequences for frugivores and folivores
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DOI：
10.2307/2388423
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发表时间：
1988-03
期刊：
影响因子：
2.1
通讯作者：
A. D. Johns
中科院分区：
文献类型：
--
作者：
A. D. Johns
热带雨林的机械化选择性采伐通常只会砍伐一小部分木材，但附带的损害可能会很严重。在马来西亚西部的一片龙脑香林中，3.3%的树木被砍伐，50.9%的树木被摧毁，所有树木分类群和所有大小级别的树木都受到了同样的破坏。因此，食果动物和食叶动物的食物来源的总体可获得性急剧减少，即使在木材本身不被动物使用的地方。在某种程度上，食物来源的最初损失可能会被那些幸存下来的树木的繁殖和营养活动的增加所缓冲。选择性采伐从森林地区收获最有价值的树木。在持续的产量条件下，剩余的林分可以自然再生，也可以通过一定的管理程序再生，以促进商业上重要的木材物种的重建（Baur 1964）。这是整个潮湿热带地区最常见的森林开发形式（联合国教科文组织，1978年），尽管所采用的技术、单位面积砍伐的木材数量以及对环境造成的总体损害差异很大。典型伐木作业的环境影响尚未得到广泛研究。大多数现有资料涉及商业上重要的用材树木，并针对提高森林生产力或森林管理的其他方面（例如，UNESCO 1978，Whitmore 1984）。在龙脑香林中，机械化选择性采伐造成的损害程度通常估计为50%的林分（Ewel &孔德1976），尽管它们取决于采伐水平（Nicholson 1958，Burgess 1971）。与伐木有关的损害对雨林环境的影响最大，可能是决定持续生产林业是否可行的关键因素（Skorupa & Kasenene 1984，Whitmore 1984）。选择性采伐作业对雨林野生动物的影响也没有得到广泛研究，几乎所有可用的信息都与脊椎动物物种有关（Johns 1983 a，B，c，1985，1986 a，B; Skorupa 1986）。本文探讨了在马来西亚西部的龙脑香林的选择性采伐作业的生态效应。它考虑了森林本身结构和组成的变化，以及这些变化如何影响食果和食叶哺乳动物和鸟类的食物资源。研究区域本研究在马来西亚西部彭亨双溪特锦森林特许经营区进行（4？10'N，102？40 'E）。主要研究地点（Combustion 13 C）位于从彭亨河旧洪泛区升起的山脊系统的边缘，海拔高度从300米到450米不等。植被主要是丘陵龙脑香林（参见Symington 1943，Whitmore 1984），尽管它缺乏龙脑香树Shorea curtisii的特征聚集。排水良好的土壤中占主导地位的其他Shoreai种。和挺水豆科植物如Koompassia spp.和Intsia palembanica;排水不好的土壤支持低身材的植被，占优势的大戟和藤本植物。物种多样性极高;在总面积为2.08公顷的样带中鉴定了110属181种（Johns 1983 a）。在26个月的研究期的14个月后，在这个主要研究地点开始选择性记录，该过程需要6个月才能完成。为了补充这个主要研究地点的结果，在附近的森林（最初是同一森林区块的一部分）进行了植物学和动物学调查，这些森林之前已经记录了1-2年（C5 A），3-4年（CIA）和5-6年（C2）。双溪德锦使用的伐木系统是一种“选择性森林管理系统”（Canonizado 1978;有关描述，请参见Whitmore 1984）。伐木是高度机械化的，使用重型推土机和绞车，在绞车中，连接到山脊上的桅杆树的电缆被用来将原木拖上陡坡到装载区。该系统主要依靠森林的自然再生，辅之以在严重受损的地区重新种植苗圃培育的树苗，以提高随后采伐的木材产量。一种快速生长的外来树种，桉树deglupta，目前用于这一目的，优先于当地的硬木。桉树的种植最大限度地减少了鹿的破坏性啃食问题（Dykstra & Taylor 1976）。BIOTROPICA 20（1）：31-37 1988 31 1985年4月8日接收，1986年9月11日接受修订。本内容于2016年9月27日星期二03：59：52 UTC从 157.55.39.211下载所有使用均受 http://about.jstor.org/terms表1的约束。主要研究区域树木死亡原因。%树木总数
Mechanized selective logging in tropical rain forest typically removes only a small percentage of timber trees, but incidental damage may be severe. In a West Malaysian dipterocarp forest, extracting 3.3 percent of trees destroyed 50.9 percent, and damage was spread equally among all tree taxa and all size classes. The overall availability of food sources for frugivores and folivores is thus drastically reduced, even where timber trees are not themselves used by animals. To some extent, the initial loss of food sources may be buffered by increased reproductive and vegetative activity of those trees that remain. SELECTIVE LOGGING HARVESTS THE MOST VALUABLE TREES from a forest area. Under sustained-yield conditions, the residual stand is then left to regenerate, either naturally or with certain management procedures designed to promote the reestablishment of commercially important timber species (Baur 1964). It is the commonest form of forest exploitation throughout the humid tropics (UNESCO 1978), although the techniques employed, the number of timber trees cut per unit area, and overall damage caused to the environment vary considerably. The environmental effects of typical logging operations have not been widely studied. Most available information concerns the commercially important timber trees and is directed toward improving forest productivity or other aspects of forest management (e.g., UNESCO 1978, Whitmore 1984). Damage levels resulting from mechanized selective logging in dipterocarp forest are generally estimated at 50 percent of the stand (Ewel & Conde 1976), although they are dependent on the extraction level (Nicholson 1958, Burgess 1971). It is the damage associated with logging that has the greatest impact on the rain forest environment and may be the crucial factor determining whether sustained-yield forestry is feasible (Skorupa & Kasenene 1984, Whitmore 1984). The effects of selective logging operations on rain forest wildlife also have not been widely studied, and almost all available information concerns vertebrate species (Johns 1983a, b, c, 1985, 1986a, b; Skorupa 1986). This paper examines the ecological effects of a selective logging operation in West Malaysian dipterocarp forest. It considers both the changing structure and composition of the forest itself, and how these changes affect the food resources available to frugivorous and folivorous mammals and birds. STUDY AREA The study was conducted in the Sungai Tekam Forestry Concession, Pahang, West Malaysia (4?10'N, 102?40'E). The main study site (Compartment 13C) was located on the edge of a ridge system rising from the old floodplain of the Pahang River, and varied from 300 to 450 m ASL. The vegetation was primarily hill dipterocarp forest (see Symington 1943, Whitmore 1984), although it lacked the characteristic aggregations of the dipterocarp Shorea curtisii. Well-drained soils were dominated by other Shoreai spp. and by emergent legumes such as Koompassia spp. and Intsia palembanica; less well-drained soils supported lower-stature vegetation with a predominance of euphorbs and lianas. Species diversity was extremely high; 181 species of 110 genera were identified within sample transects of 2.08 ha total area (Johns 1983a). Selective logging began at this main study site after 14 mo of the 26-mo study period, and the process took 6 mo to complete. To supplement results from this main study site, botanical and zoological surveys were carried out in nearby forest (originally part of the same forest block) that had been logged 1-2 yr (C5A), 3-4 yr (CIA), and 5-6 yr (C2) previously. The system of logging in use at Sungai Tekam is a "selective forest management system" (Canonizado 1978; for description see Whitmore 1984). Logging is highly mechanized, using both heavy bulldozers and winch rigs in which cables attached to ridgetop spar-trees are used to drag logs up steep slopes to loading areas. The system relies largely upon natural regeneration of the forest, supplemented by replanting severely damaged areas with nursery-reared seedlings to enhance the timber yield in subsequent croppings. A fast-growing exotic species, Eucalyptus deglupta, is currently used for this purpose in preference to local hardwoods. Planting of Eucalyptus minimizes problems of destructive browsing by deer (Dykstra & Taylor 1976). BIOTROPICA 20(1): 31-37 1988 31 I Received 8 April 1985, revision accepted 11 September 1986. This content downloaded from 157.55.39.211 on Tue, 27 Sep 2016 03:59:52 UTC All use subject to http://about.jstor.org/terms TABLE 1. Causes of tree mortality in the main study area.% total number of trees