海南岛尖峰岭热带山地雨林下层乔木中华厚壳桂光合生理生态特性的研究   总被引：19，自引：2，他引：19       下载免费PDF全文

陈德祥  李意德  骆土寿  陈步峰  林明献 《林业科学研究》2003,16(5):540-547

2001年旱季,用Li 6400便携式光合测定仪对尖峰岭热带山地雨林下层乔木中华厚壳桂主要光合生理生态因子进行了初步测定,结果显示:冠层不同部位叶片的净光合速率无明显差异;中华厚壳桂具有较低的光饱和点(800μmol·m-2·s-1)、光补偿点(15～20μmol·m-2·s-1)和最大光合速率(≤7μmolCO2·m-2·s-1)等耐荫性光合特性,并且缺乏对高光强改变的光合调节能力,但对光斑却有快速的光合响应能力;短期内高CO2浓度会使其光合速率增加,但对气孔导度和蒸腾作用却有抑制作用;在光合最适温度范围内,温度的升高将明显促进光合作用,温度升高4℃能够使其净光合速率平均提高1 6倍,但一旦超过此范围,温度的升高却将抑制光合作用的进行。在自然条件下净光合速率与光照、温度、CO2浓度及气孔导度并无明显的相关关系,而在控制条件下却呈显著的曲线相关。  相似文献   

海南岛热带森林生物多样性研究进展   总被引：3，自引：0，他引：3  

陈磊夫  余雪标  黄金城  王珠娜  陈仁利 《热带林业》2006,34(1):8-11

生物多样性是生态学研究中一个重要的领域,海南岛热带林有很高的生物多样性。阐述海南岛热带林生物多样性的意义和研究进展,介绍海南岛热带林物种多样性、遗传多样性、生态系统多样性和景观多样性特点,结合生物多样性锐减的现状提出了相应的保护建议。  相似文献   

热带山地雨林生态系统水文化学循环规律的研究   总被引：7，自引：1，他引：7       下载免费PDF全文

陈步峰  周光益  曾庆波  李意德  吴仲民 《林业科学研究》1997,10(2):111-117

根据５ａ定位观测，对尖峰岭热带山地雨林更新林生态系统的水文化学循环规律的数据分析表明，年均降雨量为２６６８．３ｍｍ，其中总径流量占４６．７％，蒸散量５３．３％，冠层截留量１４．０％。Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ的年均降雨输入量为７８．４ｋｇ／（ｈｍ２·ａ），总径流输出５６．７ｋｇ／（ｈｍ２·ａ），净积累２１．６ｋｇ／（ｈｍ２·ａ）；Ｓｉ、有机Ｃ、Ａｌ、Ｍｎ的年均降雨输入量为２５．０ｋｇ／（ｈｍ２·ａ），总径流输出为１１２．３ｋｇ／（ｈｍ２·ａ），净损失８７．３ｋｇ／（ｈｍ２·ａ），更新林系统仅处于更新进展过程中，同时证实了冠层对降水化学的淋溶效应，净淋溶系数达４．１１；提出了降雨、林内净降雨、总径流的各水化学物含量与其相应水量的回归模式  相似文献   

Agroforestry in the management of sloping lands in Asia and the Pacific   总被引：2，自引：1，他引：2  

E. T. Craswell  A. Sajjapongse  D. J. B. Howlett  A. J. Dowling 《Agroforestry Systems》1997,38(1-3):121-137

Steeply sloping lands are widespread in the tropics. An estimated 500 million people practice subsistence agriculture in these marginal areas. Continued population growth has led to the intensified cultivation of large areas of the sloping lands, exacerbating the problem of soil erosion. Although research shows that alley cropping and other contour agroforestry systems can stabilize the sloping lands, these systems have not been widely adopted by farmers. The Framework for Evaluating Sustainable Land Management (FESLM) has been tested in sloping land areas in the Philippines. Sustainable land management must be productive, stable, viable, and acceptable to farmers, while protecting soil and water resources. Farms on which contour hedgerow intercropping has been adopted meet the multifaceted requirements of FESLM, whereas the farmers' current practice does not. Appropriate land management measures for particular locations depend on a complex suite of social, economic, and biophysical factors, and need to be developed in participation with farmers. The role of agroforestry in sustainable management of sloping lands is the subject of networks coordinated by the International Board for Soil Research and Management (IBSRAM) in seven countries in Asia (ASIALAND) and four countries in the Pacific (PACIFICLAND). We review selected outcomes from a wealth of network data. From these results the following conclusions about the sustainability of various agroforestry systems for sloping lands can be drawn: • In the Pacific, soil loss from sloping lands due to water erosion under farmers' current practices is episodic, unpredictable, and possibly not severe; • Agroforestry systems that utilize legume shrubs, fruit trees, coffee (Coffea spp.) or rubber (Hevea brasiliensis) provide useful economic returns, but are not an essential component in terms of soil protection because grass or pineapple (Ananas comosus) planted on the contour are equally effective in reducing erosion; • Agricultural intensification will lead to nutrient mining, reduction of aboveground biomass, declining yields, and less soil protection unless external sources of nutrients are used; • nitrogen can be effectively supplied using legumes; • Cash derived from hedgerow trees and/or shrubs may providean incentive for their adoption by farmers, as well as funds to purchase external inputs such as fertilizers; • Labor may be a major constraint to the adoption of complex agroforestry systems. We also discuss the information management systems required to effectively manage and utilize the extensive sets of experimental and indigenous data being accumulated. We believe such information systems can facilitate technology transfer across and between regions, and improve the efficiency of research into agroforestry and other land-management approaches. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

海南尖峰岭国家级保护区青皮林资源与乔木层群落学特征   总被引：14，自引：3，他引：14  

李意德  方洪  罗文  陈焕强  蒋忠亮 《林业科学》2006,42(1):1-6

三分区位于尖峰岭国家级自然保护区,目前区内有海南岛保存最好的青皮林.根据1.38 hm2的样地资料,林分平均蓄积量高达469.773m3·hm-2;平均胸径28.6 cm,最大胸径143.3 cm;林木组成复杂,记载种类300多种.青皮为热带常绿季雨林的表征种和建群种,重要值为16.8,该种群的径级和年龄结构合理,具有反J曲线的正常增长型种群.聚类分析结果表明:属于典型热带常绿季雨林类型的青皮林群落分布在海拔300～650 m处,伴生树种有白茶、细子龙、野生荔枝等.调查区内有8种国家重点保护植物,其中坡垒为国家一级保护植物,青皮是关键种,该区的森林生态系统具有极高的保护价值.  相似文献   

主要热带相思在华南地区的生长及适应性探讨   总被引：26，自引：2，他引：26       下载免费PDF全文

杨民权 《林业科学研究》1990,3(2):155-161

热带相思为多用途树种，多数种类在华南热带、南亚热带地区的不同类型土壤上表现出较强的适应性，马占相思、厚荚相思等3－4年生幼林年平均生长量高2－4m，胸径3－4cm。但热带相思的发展，往往受到低温的制约，其栽培北界一般可到20℃等温线，局部地区可至18℃而以年积温＞7000℃，极端最低平均温5℃以上为其适生范围。栽培热带相思易达到较高社会效益和经济效益。在农用林业、改良土壤、固氮等方面都能起到良好的作用，不少树种其木材可用作建筑、家具、单板等，木材基本密度460－620kg/m^3，如作为造纸原料，具有广阔的前景。  相似文献   

Mass propagation method from the cutting of three dipterocarp species     

Chikaya Sakai  Atok Subiakto  Hani Sitti Nuroniah  Naoto Kamata  Koji Nakamura 《Journal of Forest Research》2002,7(2):73-80

We developed a vegetative propagation system for mass-producing three dipterocarps species,Shorea selanica Bl.,Shorea leprosula Mig., andShorea platyclados Sloot. This system uses fog evaporative cooling inside a greenhouse to reduce the leaf-to-air vapor pressure deficit (leaf-to-air VPD) inside the propagator, even under high irradiance conditions. This cooling method has no negative influence on medium conditions such as overwetting. A plastic tent propagator combined with this cooling method was used for vegetative propagation experiments. In mass-production experiments, the annual rooting percentages from the cuttings were low in the first 2 years (1997–1998) due to operational problems of the tent propagator (S. selanica, 48–51%;S. leprosula, 56–59%;S. platyclados: 50–63%). A hard cover propagator improved the rooting percentages in the mass-production experiments in 1999 because it made operations easier (S. selanica, 70%;S. leprosula, 77%;S. platyclados, 77%). This system, which uses a combination of fog evaporative cooling and a hard plastic propagator, should be useful for the mass propagation of these dipterocarp planting stocks. This study was carried out under a joint project of the Ministry of Forestry, Indonesia and Komatsu Ltd. The project was supported by Research Association for Reforestation of Tropical Forest (RETROF) organized by Japanese Forestry Agency.  相似文献   

Vertical profiles of environmental factors within tropical rainforest, Lambir Hills National Park, Sarawak, Malaysia     

Tomo’omi Kumagai  Koichiro Kuraji  Hironori Noguchi  Yuri Tanaka  Katsunori Tanaka  Masakazu Suzuki 《Journal of Forest Research》2001,6(4):257-264

Environmental factors, such as global solar radiation, wind speed, air temperature, humidity, and CO₂ concentration, were measured above and within the canopy of a tropical rainforest in Lambir Hills National Park, Sarawak, Malaysia. Few data concerning the environment of this forest have been reported. Intensive observations were carried out in 1998, 1999, and 2000 with the following results: (1) The fraction of global solar radiation reaching the upper layer of the canopy varied with global solar radiation above the canopy. Even though the global solar radiation above the canopy fluctuated, the fraction of that reaching the lower canopy and the ground was constantly approximately 5%. (2) The fraction of wind speed reaching each layer of the canopy increased with wind speed above the canopy. Little wind was usually present at the lower canopy. (3) The daytime air temperature at the canopy top was higher than that near the ground. The maximum difference between the air temperature at the canopy top and that at the ground was about 5°C, and the diurnal temperature ranges at the canopy top and those at the ground were about 8°C and about 5°C, respectively. The highest daytime water vapor pressure occurred within the canopy and particularly near the ground. Vertical gradients of water vapor pressure during the day were steep, probably because of high transpiration. (4) In the 1998 observation the minimum and the maximum CO₂ concentrations were 360 ppm in the day and 450 ppm at night, while in the 2000 observation the minimum and the maximum CO₂ concentrations were 350 ppm in the day and 540 ppm at night. The higher CO₂ concentration in the daytime and the lower concentration at night observed during the 1998 observation period were probably due to reduced photosynthesis and soil respiration caused by exceptional dry conditions during the observation period.  相似文献   

The structure of four home gardens in the Petén,Guatemala     

A. R. Gillespie  D. M. Knudson  F. Geilfus 《Agroforestry Systems》1993,24(2):157-170

Forest-covered home gardens around the tropical world vary in their structure, but serve to supply food and other products for direct family consumption or marketing. Little quantitative data exist defining home garden structure. Thus, this study was undertaken to examine the variation in home garden structures in response to market or household needs and the subsequent variation in light interception and productivity.Four home gardens were studied in the Department of the Petén, in northern Guatemala. Areal extent and height of canopies were mapped in transects through four gardens representing a range of site water regimes and market orientation. Light intensities incident on the ground were measured along each transect to assess light use. Results showed structural complexity, with full canopy closure in the one or more layers within the canopy for most gardens. The garden architectures made efficient use of light and space, with intersive management for food and fuel production. Farmers grew the crops for both cash and family subsistence. One home garden on a comparatively dry site with shallow soil seemed less structured, with only a single broken canopy layer, but with diverse species of plants.The results indicate that development of gardens in this area utilized existing trees, thinning them to leave the most useful, and inserting other desirable trees and shrubs in the understory and in open spaces. This strategy seemed to maximize light use, regardless of market orientation.This look at the structure and composition of four home gardens, in a forested area of current immigration, demonstrated (1) variety of organization and plant components, (2) different architecture for different soil/site conditions and market orientations, and (3) efficient use of available light through the arrangement of plants.  相似文献   

Tropical Tree Growth and Longevity: Validation of Growth Simulation,a Bootstrapping Model     

Mariby Cruz  Milton Lieberman 《Journal of Sustainable Forestry》2020,39(7):674-691

ABSTRACT

Growth Simulation, an analytical modeling technique, has been increasingly used in ecological studies and practical forestry applications where dendrochronology is not applicable. The technique uses randomly sampled diameter increments from tagged trees over a known time interval to assemble a statistical sample of lifetime growth trajectories. We carried out a validation of Growth Simulation using a temperate species in order to compare indirect model outputs with direct tree ring analysis. Rings were measured on sample disks cut from 55 pine branches ranging in age from 8–36 years. Assessments included lifetime growth rates, growth rate with respect to diameter and age, periodic annual increment (PAI), cross-referencing of rings by date, and autocorrelation of growth over successive periods. Tree ring analysis and Growth Simulation showed close correspondence for all parameters tested (maximum, median, and minimum growth rates; longevity estimates). Growth Simulation is found to be a robust and informative technique for studies of tropical tree growth, and is especially useful where analysis of tree rings is not feasible or when bootstrapping analysis of ring data is of interest.  相似文献