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851.
黑龙江大兴安岭森林绿色核算研究 总被引:7,自引:2,他引:5
在对国内外森林绿色核算研究综述的基础上,对黑龙江大兴安岭1997-2003年森林资源的实物量、价值量和森林绿色GDP等进行了核算。核算结果表明:黑龙江大兴安岭森林的eaGDP(environmentallyadjustedGDP)1997年为38.19×108元,2003年为57.34×108元,年均增长7.01%;森林的eaNDP(environmentallyadjustedNDP)1997年为25.70×108元,2003年为43.96×108元,年均增长9.36%。在森林绿色GDP核算的基础上,进行了资产负债和财富核算。结果表明,1997-2003年,黑龙江大兴安岭林地、林木存量价值呈减少的趋势;森林环境效益呈增加的趋势,反映在社会经济发展中对林地、林木存量的过度开发和利用。森林绿色GDP占GDP的比重和森林资源占国民财富的比重也呈下降的趋势,说明黑龙江大兴安岭虽然在天然林保护工程后,全面禁止天然林采伐,森林的生长量大于消耗量,表现为流量价值有所增加,反映森林是可持续的经营,但从存量上看对国民经济发展的支撑力是下降的。最后,研究指出,应加强生态补偿政策的研究,积极落实森林可持续经营对策和建议加强绿色财富政策的制定,以保证黑龙江大兴安岭森林的可持续发展和绿色财富的增长。 相似文献
852.
魏国印 《中国环境管理干部学院学报》2001,(2)
森林是生态系统的主体,森林资源是人类的宝贵财富和社会发展的基础。本文论述了森林可持续发展的重要意义,分析了秦皇岛森林资源现状,以及开发利用中存在的问题,探讨了秦皇岛森林资源可持续发展的对策。 相似文献
853.
Mike Liquori C. Rhett. Jackson 《Journal of the American Water Resources Association》2001,37(6):1639-1651
ABSTRACT: We surveyed first‐to third‐order streams (channel widths from 1.4 to 10 m) in the southeastern slopes of the Cascade Range of Washington and found two distinct endpoints of riparian vegetation. Where the forest overstory is dominated by park‐like Ponderosa pine (Pinus ponderosa), channels are commonly bordered with a dense scrub‐shrub vegetation community. Where fire suppression and/or lack of active riparian zone management have resulted in dense encroachment of fir forests that create closed forest canopies over the channel, scrub‐shrub vegetation communities are virtually absent near the channel. Other factors being equal, distinct differences in channel morphology exist in streams flowing thru each riparian community. The scrub‐shrub channels have more box‐like cross‐sections, lower width‐to‐depth ratios, more pools, more undercut banks, more common sand‐dominated substrates, and similar amounts of woody debris (despite lower tree density). Temperature comparisons of forest and scrub‐shrub sections of two streams indicate that summer water temperatures are slightly lower in the scrub‐shrub streams. We surmise that these morphology and temperature effects are driven by differences in root density and canopy conditions that alter dynamic channel processes between each riparian community. We suspect that the scrub‐shrub community was more common in the landscape prior to the 20th century and may have been the dominant native riparian community for these stream types. We therefore suggest that managing these streams for dense riparian conifer does not mimic natural conditions, nor does it provide superior in‐stream habitat. 相似文献
854.
Nadine A. Amlin Stewart B. Rood 《Journal of the American Water Resources Association》2001,37(6):1709-1720
ABSTRACT: Throughout western North America, willows and cottonwoods are dominant woody plants in riparian zones, streamside areas that are periodically flooded. This study compared tolerances of willows‐Salix discolor, S. exigua, and S. lutea‐and cottonwoods‐Populus angustifolia, P balsamifera, and P deltoides‐to water inundation, one component of stream flooding. Rooted cuttings were grown for 152 days in 10 cm tall pots in water depths from 2.5 to 10 cm (inundated). Shoot and root elongation growth of the inundated cottonwoods were reduced 23 and 45 percent, while S. lutea was relatively unaffected and the inundated sandbar willow, S. exigua, displayed 72 and 43 percent increases in shoot and root elongation. The inundation reduced transpiration in P deltoides and for mature P balsamifera trees that were flooded by a small reservoir on Willow Creek, Alberta. Those flooded trees died in their second year of inundation. The greater inundation tolerance of willows versus cottonwoods is consistent with observations along Midvale Creek, Montana, where beaver dams created a pond in which P trichocarpa died while willows thrived after five years. These patterns of inundation tolerance are consistent with elevational zones of occurrence as willows‐and particularly the sandbar willow—occur at low elevations close to the stream. The understanding of inundation tolerances should assist in the provision of hydrologic patterns that will conserve and restore these shrubs and trees along streams and could permit their establishment along artificial reservoirs. 相似文献
855.
城市绿色规划分析与评述 总被引:8,自引:0,他引:8
全球城市化的无序扩展给城市生态系统平衡带来了极大的挑战,在这种背景下倡导绿色规划随之成为国际潮流,因为其可以促进城市生态平衡、提供市民休憩场所和产业支持等。本文首先就城市园林、城市森林公园、都市农业等3个方面介绍了国外城市的绿色规划发展概况,着重分析了绿色规划的作用与特点,并在此基础上,本文指出了国内城市绿色规划特点和不足之处。 相似文献
856.
MARCELO TABARELLI ANTONIO V. AGUIAR LUCIANA C. GIRÃO CARLOS A. PERES ARIADNA V. LOPES 《Conservation biology》2010,24(6):1654-1663
Abstract: Despite many studies on fragmentation of tropical forests, the extent to which plant and animal communities are altered in small, isolated forest fragments remains obscure if not controversial. We examined the hypothesis that fragmentation alters the relative abundance of tree species with different vegetative and reproductive traits. In a fragmented landscape (670 km2) of the Atlantic Forest of northeastern Brazil, we categorized 4056 trees of 182 species by leafing pattern, reproductive phenology, and morphology of seeds and fruit. We calculated relative abundance of traits in 50 1‐ha plots in three types of forest configurations: forest edges, small forest fragments (3.4–83.6 ha), and interior of the largest forest fragment (3500 ha, old growth). Although evergreen species were the most abundant across all configurations, forest edges and small fragments had more deciduous and semideciduous species than interior forest. Edges lacked supra‐annual flowering and fruiting species and had more species and stems with drupes and small seeds than small forest fragments and forest interior areas. In an ordination of species similarity and life‐history traits, the three types of configurations formed clearly segregated clusters. Furthermore, the differences in the taxonomic and functional (i.e., trait‐based) composition of tree assemblages we documented were driven primarily by the higher abundance of pioneer species in the forest edge and small forest fragments. Our work provides strong evidence that long‐term transitions in phenology and seed and fruit morphology of tree functional groups are occurring in fragmented tropical forests. Our results also suggest that edge‐induced shifts in tree assemblages of tropical forests can be larger than previously documented. 相似文献
857.
The results of gradient analysis of band pine forests in the Minusinsk Depression are presented. Methods of DCA ordination and correlation analysis have been used to reveal specific features of phytocenotic diversity formation in forest communities growing in azonal habitats of this steppe depression and to test zonal and typological forest units for ecological integrity. The role of directly acting zonal and compensatory ecological factors and specific relationships between types of forest communities and ecological-topographic conditions in the main forms of relief are considered. 相似文献
858.
Andreas Mölder Marcus Schmidt Tobias Plieninger Peter Meyer 《Conservation biology》2020,34(6):1444-1451
The protection and sustainable management of habitat trees is an integral part of modern forest nature conservation concepts such as retention forestry. Bats, cavity-nesting birds, arboreal marsupials, and many different saproxylic species depend on habitat trees and their great variety of microhabitats and old-growth characteristics. With a focus on insights from temperate forests, we traced the development of habitat-tree protection over 200 years. The idea was first conceptualized by foresters and natural scientists in the early 19th century. At that time, utilitarian conservation aimed to protect cavity trees that provided roosts and nesting holes for insectivorous bats and birds. By the second half of the 19th century, habitat-tree protection was well known to foresters and was occasionally implemented. Knowledge of the protection of large old trees, a special kind of habitat tree, for sociocultural and aesthetic reasons developed similarly. But, many foresters of that time and in the following decades fundamentally rejected protection of habitat trees for economic reasons. Beginning in the 1970s, forest conservation and integrative forest management became increasingly important issues worldwide. Since then, the protection of habitat trees has been implemented on a large scale. Long-term views on the development of conservation concepts are important to inform the implementation of conservation today. In particular, historical analyses of conservation concepts allow the testing of long-term conservation outcomes and make it possible to study the resilience of conservation approaches to changing social or ecological conditions. We encourage all conservation ecologists to assess the practical and conceptual impact of the initial ideas that led to modern conservation concepts in terms of long-term biodiversity conservation. 相似文献
859.
火场安全问题始终是完成森林灭火任务的重中之重,党和国家对此高度重视。从发生危险的环境和原因入手,提出了有针对性的避险方法,以及装备改进、理论研究和训练演练等方面应该加强的技术措施,对做好扑火安全工作具有一定的指导意义。 相似文献
860.