森林火灾灾情快速预判模型

为在火灾发生时进行灾情的快速评估,为消防决策提供参考,提出一种简化的林火蔓延模型。通过遥感影像,获取火灾首日燃火点和火场边界,利用风向、风速和USDA蔓延模型数据库中对应植被类型的蔓延速度,进行林火蔓延计算,预判无干扰状态下的林火蔓延范围,以达到灾情快速预判的目的。通过2006年黑龙江省和2009年中蒙边境特大森林草原火灾案例的分析,结合运用卫星遥感图像对逐天火迹和火点解译的结果,验证该模型的可靠性及适用性。研究结果表明,基于实时遥感影像与气象预报信息,运用简化的林火蔓延模型,并结合林火宏观扩散的特征,能够对火灾灾情的发展进行快速研判。     

Decomposition of forest products buried in landfills

The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5 yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C + H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C + H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27 g OC g^?1 dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than previously reported.     

Spatial distribution of hexazinone and metabolites in a luvisolic soil

Abstract

The spatial distribution of hexazinone and two primary metabolites were measured in forest soil for two years following the aerial application of a granular formulation, PRONONE 10G, in northern Alberta. Residues were quantified using solid‐phase extraction and capillary gas chromatography. Initial deposition rates of two hexazinone treatments averaged 2.3 ± 0.5 and 4.1 ± 0.8 kg/ha for each triplicated plots. One year after application, residues of hexazinone averaged 0.25 ± 0.09 and 0.40 ± 0.02 kg/ha in 2.3 and 4.1 kg/ha treatment, respectively, in the 0–10 cm surface soil; and were distributed vertically in soil depths of 0–10, 10–20, and 20–30 cm at ratios of 10:11:2 and 10:5:2, respectively, in 2.3 and 4.1 kg/ha treatment. Metabolites A and B amounted to 15 and 30% of hexazinone, respectively. Two years after application, the vertical movement of hexazinone in soil was quantifiable to the 40‐cm depth in both 2.3‐ and 4.1‐kg/ha treatment plots. Trace amounts of hexazinone were detected at 130 cm only in the 2.3‐kg/ha plot, which is likely due to the more freely downward movement of hexazinone to deeper horizons along decayed root channels.     

LNG池火热辐射模型及安全距离影响因素研究

重点对LNG池火热辐射模型,模型应用方式,以及热辐射安全距离的影响因素做了详细研究,给出池火热辐射模型采用及安全距离计算的方法。对常用的热辐射计算模型(点源模型、LNGFire3和PoFM ISE模型)加以介绍,并对3种模型做了对比研究。PoFM ISE模型充分考虑大池火直径时不完全燃烧的因素以及风速对火焰高度的影响,建议当风速大于1.5 m/s,池火直径大于20 m时采用。同时,进一步研究影响LNG池火热辐射安全距离的各种因素,包括池火直径、风速、环境温度和湿度,从而得出不同条件下池火热辐射安全距离的要求。     

Characterization of municipal solid waste temporary storage sites: Risks posed to surrounding areas as a consequence of fire incidents

In this study temporary storage sites of municipal solid waste were characterized based on their potential social, health and environmental impacts as a consequence of spontaneous fires, by employing Boolean as well as weighted-linear-combination approaches in connection with various fuzzy set functions of population density around the storage sites. Sweden was used as the case study and data from 105 storage sites were analysed; of these, 38 were identified to be posing high risk for downwind residing population. Furthermore, during the past 10 years, the fire frequency and the average population residing within a radius of 1, 2, and 3 km were found to be comparatively higher for storage sites owned by private companies than for those owned by municipalities. The study provided first-cut information of poorly sited temporary storage sites and can help in formalizing the comprehensive risk analysis in the future.     

Ozone‐induced xeromorphism of beech leaves (Fagus sylvatica L.)

The influence of different concentrations of ozone under different light intensities on young trees of European beech (Fagus sylvatica L.) is studied. Young beeches were exposed continuously for 5 months in fumigation chambers, located outdoors, with 131±30/μg/m³O₃, and for 2 months in fumigation chambers, located in air‐conditioned greenhoouses, with 100±10, 200±20 and 300±30/μg/m³O₃, respectively. The observed symptoms point towards an increased xeromorphism in beech leaves, positively influenced by high light intensities. Ozone‐induced water stress may be the cause of xeromorphic tissue changes. On the ultrastructural level chloroplasts have become senescent.     

Radiocaesium accumulation in stemwood: integrated approach at the scale of forest stands for contaminated Scots pine in Belarus

Twenty years after the Chernobyl accident, root uptake from the surface layers of contaminated forest soils plays a major role in radiocaesium ((137)Cs) transfer to the trees and accumulation in perennial compartments, including stemwood. Trustworthy long-term predictions (modelling) of stemwood contamination with (137)Cs should accordingly be based on a reliable picture of this source-sink relationship. Considering the complexity of the processes involved in (137)Cs cycling in forest stands, elementary ratios like transfer factors (TF) were shown to be not very relevant for that purpose. At the tree level, alternatives like the wood immobilisation potential (WIP) have therefore been proposed in order to quantify the current net (137)Cs accumulation in stemwood. Our objective was here to compare WIP values determined for a series of contaminated forest stands in Belarus with the corresponding pools of (137)Cs available in the soil for root uptake. The comparison reveals that both indices are quite proportional, whatever the forest ecosystem features. This corroborates the relevancy of WIP as an indicator of the current (137)Cs root uptake by the trees, which could accordingly help to improve the existing models of (137)Cs cycling and the long-term management of contaminated forest ecosystems.     

An integrated approach to modeling resource utilization for rural communities in developing countries

Resource consumption in developing countries has been the focus of a considerable amount of research. What has been understudied however, has been the feedback affects of resource consumption on resource availability to both households and communities. Heavy reliance on natural resources and intensive smallholder agriculture common to many rural communities in developing countries has forced people to fulfill short-term needs to the detriment of long-term ecological and livelihood sustainability. This paper introduces a conceptual framework to examine how individuals and households fulfill daily caloric needs and the aggregate effects on resource availability and consumption. Data were collected from a large number of published case studies of rural land-use dynamics, growth and yield models, and human livelihoods were reviewed from scientific journals, reports published by NGOs, and government reports. Using inputs defined by the user, the model tracks annual fuelwood and agricultural land use based on meeting individual energy demands. A case-study-based analysis was patterned after smallholder agriculturalists at the family and community level. Three scenarios are presented in this paper using data from Uganda to illustrate the application of this model.     

Carbon sinks and sources in China's forests during 1901-2001

This paper reports the annual carbon (C) balance of China's forests during 1901-2001 estimated using the Integrated Terrestrial Ecosystem C-budget model (InTEC). Annual carbon source and sink distributions are simulated for the same period using various spatial datasets including land cover and leaf area index (LAI) obtained from remote sensing, soil texture, climate, forest age, and nitrogen deposition. During 1901-1949, China's forests were a source of 21.0+/-7.8 Tg C yr(-1) due to disturbances (human activities). Its size increased to 122.3+/-25.3 Tg C yr(-1) during 1950-1987 due to intensified human activities in the late 1950s, early 1960s, 1970s and early 1980s. The forests became large sinks of 176.7+/-44.8 Tg C yr(-1) during 1988-2001, owing to large-scale plantation and forest regrowth in previously disturbed areas as well as growth stimulation by nondisturbance factors such as climatic warming, atmospheric CO(2) fertilization, and N deposition. From 1901 to 2001, China's forests were a small carbon source of 3.32 Pg C, about 32.9+/-22.3 Tg C yr(-1). The overall C balance in biomass from InTEC generally agrees with previous results derived from forest inventories of China's forests. InTEC results also include C stock variation in soils and are therefore more comprehensive than previous results. The uncertainty in InTEC results is still large, but it can be reduced if a detailed forest age map becomes available.