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541.
Yangjian Zhang Hong S. He William D. Dijak Jian Yang Stephen R. Shifley Brian J. Palik 《Environmental management》2009,44(2):312-323
To achieve the overall objective of restoring natural environment and sustainable resource usability, each forest management
practice effect needs to be predicted using a simulation model. Previous simulation efforts were typically confined to public
land. Comprehensive forest management practices entail incorporating interactions between public and private land. To make
inclusion of private land into management planning feasible at the regional scale, this study uses a new method of combining
Forest Inventory and Analysis (FIA) data with remotely sensed forest group data to retrieve detailed species composition and
age information for the Missouri Ozark Highlands. Remote sensed forest group and land form data inferred from topography were
integrated to produce distinct combinations (ecotypes). Forest types and size classes were assigned to ecotypes based on their
proportions in the FIA data. Then tree species and tree age determined from FIA subplots stratified by forest type and size
class were assigned to pixels for the entire study area. The resulting species composition map can improve simulation model
performance in that it has spatially explicit and continuous information of dominant and associated species, and tree ages
that are unavailable from either satellite imagery or forest inventory data. In addition, the resulting species map revealed
that public land and private land in Ozark Highlands differ in species composition and stand size. Shortleaf pine is a co-dominant
species in public land, whereas it becomes a minor species in private land. Public forest is older than private forest. Both
public and private forests have deviated from historical forest condition in terms of species composition. Based on possible
reasons causing the deviation discussed in this study, corresponding management avenues that can assist in restoring natural
environment were recommended. 相似文献
542.
Release of PCDD and PCDF from biomass combustion such as forest and agricultural crop fires has been nominated as an important source for these chemicals despite minimal characterisation. Available emission factors that have been experimentally determined in laboratory and field experiments vary by several orders of magnitude from <0.5 μg TEQ (t fuel consumed)−1 to >100 μg TEQ (t fuel consumed)−1. The aim of this study was to evaluate the effect of experimental methods on the emission factor.A portable field sampler was used to measure PCDD/PCDF emissions from forest fires and the same fuel when burnt over a brick hearth to eliminate potential soil effects. A laboratory burn facility was used to sample emissions from the same fuels. There was very good agreement in emission factors to air (EFAir) for forest fuel (Duke Forest, NC) of 0.52 (range: 0.40-0.79), 0.59 (range: 0.18-1.2) and 0.75 (range: 0.27-1.2) μg TEQWHO2005 (t fuel consumed)−1 for the in-field, over a brick hearth, and burn facility experiments, respectively. Similarly, experiments with sugarcane showed very good agreement with EFAir of 1.1 (range: 0.40-2.2), 1.5 (range: 0.84-2.2) and 1.7 (range: 0.34-4.4) μg TEQ (t fuel consumed)−1 for in-field, over a brick hearth, open field and burn facility experiments respectively. Field sampling and laboratory simulations were in good agreement, and no significant changes in emissions of PCDD/PCDF could be attributed to fuel storage and transport to laboratory test facilities. 相似文献
543.
Acidification of soils and surface waters caused by acid deposition is still a major problem in southern Scandinavia, despite
clear signs of recovery. Besides emission control, liming of lakes, streams, and wetlands is currently used to ameliorate
acidification in Sweden. An alternative strategy is forest soil liming to restore the acidified upland soils from which much
acidified runoff originates. This cost–benefit analysis compared these liming strategies with a special emphasis on the time
perspective for expected benefits. Benefits transfer was used to estimate use values for sport ffishing and nonuse values in terms of existence values. The results show that large-scale forest soil liming is not socioeconomically profitable, while
lake liming is, if it is done efficiently—in other words, if only acidified surface waters are treated. The beguiling logic
of “solving” an environmental problem at its source (soils), rather than continuing to treat the symptoms (surface waters),
is thus misleading. 相似文献
544.
昆明“3·29”森林火灾对防控林区火灾的启示 总被引:2,自引:1,他引:1
李世友 《中国安全生产科学技术》2009,5(6):48-52
介绍昆明的“3·29”森林火灾基本情况。在对该火烧迹地进行3年跟踪调研的基础上,总结了该火灾对防控西南林区森林火灾的6点启示:(1)紫茎泽兰入侵区应慎修生土隔火带;(2)通过发挥山沟的阻火作用、营林防火、森林可燃物制炭等技术措施构建阻火林分;(3)重视森林火灾次生灾害;(4)开发新型森林灭火剂及施用技术;(5)适时运用以火灭火战术;(6)探索与集体林权制度改革相适应的森林消防对策。 相似文献
545.
Spatial Distribution and Temporal Change of Carbon Storage in Timber Biomass of Two Different Forest Management Units 总被引:2,自引:0,他引:2
Forests make up large ecosystems and can play an important role in mitigating the emissions of CO2, the most important greenhouse gas. However, they are sources of atmospheric carbon when they are disturbed by human or natural
causes. Storage of carbon through expansion and adaptive management of forest ecosystems can assist in reducing carbon concentrations
in atmosphere. This study proposes a methodology to produce spatially explicit estimates of the carbon storages (aboveground
plus belowground) depending on land use/cover changes in two different forest ecosystems during various periods. Carbon storages
for each forest ecosystem were projected according to inventory data, and carbon storages were mapped in a geographic information
system (GIS). Results showed that total carbon stored in above and belowground of both forest ecosystems increased from one
period to other because of especially increase of productive forest areas and decline of degraded forest areas as well as
protection of spruce forests subject to insect attacks. 相似文献
546.
The USDA Forest Service, Forest Inventory and Analysis program (FIA) recently produced a nationwide map of forest biomass
by modeling biomass collected on forest inventory plots as nonparametric functions of moderate resolution satellite data and
other environmental variables using Cubist software. Efforts are underway to develop methods to enhance this initial map.
We explored the possibility of modeling spatial structure to make such improvements. Spatial structure in the field biomass
data as well as in residuals from the map was investigated across 18 ecological zones in the Interior Western U.S. Exploratory
tools included directional graphs of summary statistics, three dimensional maps, Moran’s I correlograms, and variograms. Where
spatial pattern was present, field and residual biomass were kriged, and predictions made for an independent test set were
evaluated for improvement over predictions in the initial biomass map. While kriging has some potential benefit when analyzing
the field data and exploring spatial structure, kriging residuals resulted in little or no improvement in the initial biomass
map developed using Cubist software. Stationarity assumptions, variogram behavior, and appropriate model fitting strategies
are discussed. 相似文献
547.
Developing Alternative Forest Management Planning Strategies Incorporating Timber, Water and Carbon Values: An Examination of their Interactions 总被引:3,自引:0,他引:3
Currently, the integration of carbon and water values of forest ecosystems into forest management planning models has become
increasingly important in sustainable forest management. This study focuses on developing a multiple-use forest management
planning model to examine the interactions of timber and water production as well as net carbon sequestration in a forest
ecosystem. Each forest value is functionally linked to stand structure and quantified economically. A number of forest management
planning strategies varying in the amount of water, carbon, and timber targets and flows as constraints are developed and
implemented in a linear programming (LP) environment. The outputs of each strategy are evaluated with a number of performance
indicators such as standing timber volume, ending forest inventory, area harvested, and net present value (NPV) of water,
timber, and carbon over time. Results showed that the cycling time of forest stands for renewal has important implications
for timber, water, and carbon values. The management strategies indicated that net carbon sequestration can be attained at
a significant cost in terms of foregone timber harvest and financial returns. The standing timber volumes and ending forest
inventories were among the most important factors determining whether the forest constitutes a net carbon sink or source.
Finally, the interactions among the forest values were generally found to be complementary, yet sometimes contradictory (i.e.,
negatively affecting each other), depending on the assumed relationship between forest values and stand structure. 相似文献
548.
土地利用变化及林业(LUCF)活动是生态固碳最重要手段。研究确定LUCF温室气体排放核算制度和方法,对平衡碳排放、开展全国统一碳市场交易具有重要基础作用。在综述LUCF温室气体核算理论和方法基础上,借鉴IPCC指南和《省级温室气体清单编制指南(试行)》推荐的基本方法,构建了符合地域特色的LUCF温室气体排放核算制度和方法。采用2014年第九次国家森林资源清查数据,以全国低碳试点省陕西省为实证对象,初步核算了陕西省LUCF温室气体的净排放量,并从排放能力、排放结构和空间特征等角度揭示了陕西省LUCF温室气体的排放特征。结果显示:(1)2014年,陕西省LUCF温室气体净吸收量为1 698.42万t CO_2e,其中森林及其他木质生物质碳贮量净吸收1 852.67万t CO2e,森林转化净排放154.25万t CO_2e。(2)乔木林等优势树种,是陕西省LUCF温室气体排放中重要的固碳源(吸收源)。(3)陕南地区是重要固碳贡献区,陕北地区森林固碳能力较差。最后,针对LUCF温室气体排放核算制度和方法不够完善、森林固碳能力差异较大、区域固碳分化严重等问题,提出了健全温室气体核算制度、平衡森林资源空间分布、改善固碳树种结构等加强陕西省LUCF活动应对气候变化统计核算制度和能力建设的基本措施。 相似文献
549.
Małgorzata Mędyk Małgorzata Grembecka Jerzy Falandysz 《Journal of environmental science and health. Part. B》2017,52(8):577-583
Edible mushrooms (Albatrellus ovinus, Boletus edulis, Clitocybe odora, Gomphidius glutinosus, Leccinum scabrum, Leccinum versipelle, Lycoperdon perlatum, Suillus bovinus, Suillus luteus, and Xerocomus subtomentosus) collected from unpolluted areas of the city of Umeå and its outskirts in the northern part of Sweden were examined for contents of toxic metallic elements (Cd, Pb, and Ag) and essential macro- and microelements (K, Na, Ca, Mg, Cu, Fe, Mn, and Zn) using a validated method and a final measurement by flame atomic absorption spectroscopy (F-AAS). The median values of the toxic metallic element concentrations (in mg kg?1 dry biomass, db) ranged from: 0.12–3.9, 0.46–5.1, and 0.91–6.2 for Ag, Cd and Pb, respectively. For the essential metallic elements, the median values of concentrations ranged from: 24000–58000, 15–2000, 59–610, 520–1900, 2.0–97, 16–150, 15–120, and 4.3–26 mg kg?1 db for K, Na, Ca, Mg, Cu, Zn, Fe, and Mn, respectively. The baseline concentrations of the metallic elements determined in mushrooms were mainly affected by the fungal species. The assessed probable maximal dietary intake of Cd (0.002 mg kg?1 body mass) solely from a mushroom meal was only slightly below a revised value of the tolerable weekly intake for this element, while for Pb (0.003 mg kg?1 body mass) it was tenfold below the provisionally tolerable weekly intake. 相似文献
550.
Emission factors for PCDD/PCDF determined from open combustion are used to estimate national emission budgets; therefore, it is important to have confidence in their accuracy. It has been suspected that artefacts may form due to the presence of hot metal surfaces of sampling equipment, thus skewing emission factors. In this study, emissions of PCDD/PCDF from open burning of forest biomass over a brick hearth were sampled. Five experiments were carried out using a portable sampler. Experiments were designed where the key variable, sample hood and inlet temperatures were manipulated. Other variables such as fuel origin, type and density were consistent. The measured concentration of PCDD/PCDF in the smoke samples ranged from 0.01 μg TEQ (t fuel)−1 at the lowest maximum hood temperature (185 °C) to 15 μg TEQ (t fuel)−1 at the highest maximum hood temperature (598 °C). when hood inlet temperatures exceeded 400 °C emission factors were significantly elevated and this is attributed to the formation of artefacts that can cause the over estimation of emission factors. The increase in hood temperature also resulted in a change in the PCDD/PCDF congener and homologue profile of the emissions. For example at the lowest temperature (Fire 1) the PCDD/PCDF ratio measured was 50:1, whereas at the highest temperature (Fire 5) this ratio was about 0.53:1. When the sampler hood and inlet temperatures were kept in the normal operating range of <200 °C, emission factors were comparable to those observed in many previous studies in Australia with emissions dominated by PCDD. 相似文献