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991.
Riparian areas of large streams provide important habitat to many species and control many instream processes — but is the same true for the margins of small streams? This review considers riparian areas alongside small streams in forested, mountainous areas of the Pacific Northwest and asks if there are fundamental ecological differences from larger streams and from other regions and if there are consequences for management from any differences. In the moist forests along many small streams of the Pacific Northwest, the contrast between the streamside and upslope forest is not as strong as that found in drier regions. Small streams typically lack floodplains, and the riparian area is often constrained by the hillslope. Nevertheless, riparian‐associated organisms, some unique to headwater areas, are found along small streams. Disturbance of hillslopes and stream channels and microclimatic effects of streams on the riparian area provide great heterogeneity in processes and diversity of habitats. The tight coupling of the terrestrial riparian area with the aquatic system results from the closed canopy and high edge‐to‐area ratio for small streams. Riparian areas of the temperate, conifer dominated forests of the Pacific Northwest provide a unique environment. Forest management guidelines for small streams vary widely, and there has been little evaluation of the local or downstream consequences of forest practices along small streams.  相似文献   
992.
In recent years, researchers and policy makers have recognized that nontimber forest products (NTFPs) extracted from forests by rural people can make a significant contribution to their well-being and to the local economy. This study presents and discusses data that describe the contribution of NTFPs to cash income in the dry deciduous forests of Orissa and Jharkhand, India. In its focus on cash income, this study sheds light on how the sale of NTFPs and products that use NTFPs as inputs contribute to the rural economy. From analysis of a unique data set that was collected over the course of a year, the study finds that the contribution of NTFPs to cash income varies across ecological settings, seasons, income level, and caste. Such variation should inform where and when to apply NTFP forest access and management policies.  相似文献   
993.
发挥地方资源优势,促进油茶产业化   总被引:2,自引:0,他引:2  
本文对实行油茶产业化的必要性和可能性进行了详细论述,并为发展南方丘陵地方特色经济林-油茶林资源,促进其产业化提供了有利的对策。  相似文献   
994.
ABSTRACT: Forest buffers adjacent to water bodies are widely prescribed in forest management to protect ecological functions of riparian systems. To date, buffers have been applied on the landscape uniformly without quantifying their effectiveness or the effects they have on landscape characteristics. Our objective was to quantify landscape characteristics (amount of edge and interior forest) when buffers were applied to water bodies in a 100 by 100 km area of northern Minnesota. We used a Landsat classified image in a geographic information system platform to apply two buffer widths ?28.5 m and 57 m — to water bodies, including nonforested wetlands, intermittent or perennial streams, and lakes. A total of 107,141 ha (18.3 percent) of the forest area was adjacent to and within 28.5 m of these water bodies, while 201,457 ha of forest was within 57 m, representing 34.4 percent of the total forest area. Imposing a 28.5 m buffer on water bodies increased the amount of edge and interior forest in the study area. When water bodies were buffered with a 57 m forest strip, we found a slight increase in forest edge from the current condition, and this buffer width resulted in the largest amount of interior forest. Interior forest increased with the 57 m buffer due to the density of water bodies in this region; adjacent water bodies coalesced when buffers were applied and formed isolated forest islands that contained forest interior habitat. Instead of wholesale application of set width riparian buffers, we suggest that ecological conditions of riparian areas be evaluated on a site level and that areas that currently provide important riparian conditions be maintained on the landscape with appropriate management practices.  相似文献   
995.
Cultural taboos and their sanctionshave helped to check abuse of the environmentat least among the local people. The disregardfor these traditional checks and balancesespecially among Christians has adverselyaffected their enforcement at this time. Theenvironment and culture preservation inAwka-South were investigated. The faithfulobservance of the traditional laws in the studyarea was attributed to the fact that Awka-Southarea had remained occupied by the same peoplefor centuries. The study showed that thepreserved forests and their shrines in Nibotown have largely remained intact. In Nisetown, however, with nine shrines still inexistence, the rules have relaxed a little,mainly because they embraced modernization. Inthis town, the fringes of the forests may beused for farming but no felling of trees wouldbe allowed. The ``god' of the shrine in Obunaguvillage was much revered until the advent ofChristianity. This religion has had an erodingeffect on the taboos, which were put in placeto protect their forests and streams. Theabandonment of traditional cultural practicesis doing harm that goes beyond the abrogationof traditional cultural practices to seriousthreat to natural environmental structures. Thecultures of the different tribes in Nigerianeed to be revisited for evaluation and studiesto enable their integration into modernpractices that will make the environment moresustainable. This will be more productive thanthe unilateral introduction of programs,execution, and maintenance methods that arecompletely new, or in many cases run contraryto the cultural practices of the local peopleand tribes of Nigeria.  相似文献   
996.
Conservation of Biodiversity: How Are We Doing?   总被引:1,自引:0,他引:1  
A question rarely raised in discussions on biodiversity conservation, but surely the biggest question of all, is “How much time do we have left before the mass extinction underway surpasses our best efforts to contain it?” This prompts a further prime question because—and unlike all other problems, whether environmental or otherwise—the biotic crisis threatens to leave a severely impoverished planet for millions of years ahead; “Why do we not undertake the necessary actions to get on top of the problem before it gets on top of us?”  相似文献   
997.
作者以生态旅游理论为基础,分析了我国森林生态旅游的发展状况,并以加入WTO为背景从中找出存在的问题,进而提出入世后推进我国森林生态旅游发展的对策。  相似文献   
998.
Mugla is a city that is located in the southwest part of Turkey. Three thermo-electric power plants called Yatagan (3 × 210 MW) and Yenikoy (2 × 210 MW)and Kemerkoy (Gokova, 3 × 210 MW) havebeen constructed in this region and also have begun operation in 1982 – 1983 – 1984 (three units), in 1988 and in 1995, respectively. The Pinus brutia forests in Yerkesik–Denizova region have been under the common effects of Yenikoy and Yatagan thermo-electric power plants. Therefore, these Pinus brutia forests have startedto dry in groups since 1988. In addition, Kemerkoy thermo-electric power plant, began operation in 1995.Polluting gases arrived in Denizova-Yerkesik throughKoca Stream Valley Forests.Increasing quantities of polluting gases and especially SO2 have dried the trees in large amounts in this 1650 ha forestland area. YataganThermo-electric power plant has caused drying of Pinus brutia in Bencik Mountain, which was on the south in 1984–1985. The same phenomenon was seen in Denizova-Yerkesik Forest in 1999–2000. It was observed that sulphur content was varying between 4218–6676 ppm at the Pinus brutia needle samples taken in this region on 16 December 2000. Sulphur contents were correlated with the age of needle (1–2 yr old), density of yellow stains on the needles and amount of drying needles. Particularly in 1996–2000 period, the destruction of chlorophyll in needles due to the impacts of SO2 was also correlated with narrowing of the annual rings from one year to another. The narrowing ratio of yearly rings reached 60–504% for 94–95 yr old, and 375–661% for 58–63 yr old Pinus brutia trees during the 1986–1990, 1991–1995 and 1996–2000 periods.All these results clearly showed that the decrease in the chlorophyll content in needles under the effect of air pollution caused important reduction in the raw timber production and its inputs to the economy. In other words, drying due to increased ecological sensitivity or direct hazard of pollutants emitted by the power plants and cutting of trees have been notably increased in the region. This has created serious economic losses.  相似文献   
999.
本文概述了环境保护与森林生态可持续发展的含义与森林旅游资源的特点,阐明了实现森林旅游生态可持续发展的必要性,及实现森林旅游生态持续的途径。  相似文献   
1000.
Streamwater chemistry and spatial flow dynamics from a subalpine Abies fabri forest in an experimental watershed located in the east slope of Gongga Mountain were analyzed to gain insights into the gradient effect of primary community succession on the stream biogeochemical process. Results showed that high sand content (exceeding 80%) and porosity in the soil(exceeding 20% in A horizon and 35% in B horizon), as well as a thick humus layer on the soil surface, made the water exchange quickly in the Huangbengliu (HBL) watershed. Consequently, no surface runoff was observed, and the stream discharge changed rapidly with the daily precipitation. The flow trends of base ions in the stream water were influenced by the Abies fabri succession gradient. Ca^2 , HCO3^- and SO4^2,- were the dominant anions in the streamwater in this region. A significant difference of Ca^2 , HCO3^- and SO4^2- concentration exported between the succession stages in the watershed can be found. But they had the similar temporal change in the stream flow. Ca^2 , HCO3^- and SO4^2- showed significantly negative correlations with the daily precipitation and the stream discharge. Concentrations of Cl^- , Na^ , K^ , and Mg^2 were low in all streamwaters monitored and we observed no differences along the Abies fabri succession gradient. Low ratios of Na. (Na Ca) (range from 0.1 to 0.2) implied cations were from bedrock weathering (internal source process in the soil system) in this region. But, a variance analysis showed there were almost no differences between rainwater and streamwaters for Mg^2 , Na^ , K^ , and Cl^- concentrations. This indicated that they might be come from rainfall inputs(external source). The highly mobile capacity, rapid water exchange between precipitation and discharge, and long-term export lead to this observed pattern were suggested.  相似文献   
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