河南省雨雪冰冻灾害森林资源损失调查与分析

2008年1月至2月,我国特大雨雪冰冻灾害给林业造成了巨大损失。这场特大雨雪冰冻灾害也使我省森林资源遭受一定的损失。我省于2008年3月至5月对全省雨雪冰冻灾害森林资源损失情况进行了调查,本人参与了调查并对调查结果进行了分析。     

森林雨雪冰冻灾害原因分析及防范措施的探讨

通过对黄山区2008年雨雪冰冻灾害森林资源损失调查,分析了主要灾害类型、分布特征、灾害程度、灾害原因、发生次生灾害的隐患以及对林业产生的主要影响,提出了预防雨雪冰冻灾害的措施。     

浙江省竹林冰雪灾情分析与更新复壮措施

针对2008年特大雨雪冰冻灾害,分析了浙江省竹林雨雪冰冻灾害状况,经济损失、受灾原因,提出了受灾竹林更新复壮的原则和技术措施。     

雨雪冰冻灾害对竹林生态系统影响及病虫控制

主要探讨了雨雪冰冻灾害对竹林生态系统的影响,分析了灾害产生的主要原因及灾后病虫害发生的趋势分析,并提出了雨雪冰冻灾害后竹林生态系统调控及病虫害控制一些关键技术措施.     

江西省湿地松受雨雪冰冻灾害折断原因的调查与分析

湿地松是江西省的主要造林树种之一,在2008年初的雨雪冰冻灾害中受损尤为严重,突出表现为折断。笔者利用赴江西省指导雨雪冰冻灾害森林资源损失调查评估工作的机会,对江西省湿地松受雨雪冰冻灾害折断的原因进行了专题调研,总结了经验及教训,以期对林业灾后重建及恢复提供借鉴。     

雨雪冰冻灾害对毛竹林的影响及恢复技术研究综述

在总结毛竹林雨雪冰冻灾害特征的基础上,综述了海拔、坡度、坡向、坡位、土层厚度等环境因子对毛竹林灾害程度的影响,认为海拔、坡度是主要的环境影响因子。竹林经营类型(纯林、混交林)、立竹密度、立竹年龄结构、大小年等林分结构状况与灾害程度密切相关。指出了毛竹林混交经营,合理林分结构建立,科学施肥,立竹钩梢等毛竹林预防雨雪冰冻灾害和灾后恢复技术,总结提出了毛竹林雨雪冰冻灾害影响因子,增强抵御雨雪冰冻灾害能力的林分结构模式优化,灾后快速恢复及经济效益提高或稳定的竹林复合经营等需重点研究的方向。     

河南省信阳市雨雪冰冻灾害后茶叶恢复经营措施初探

2008年初的雨雪冰冻灾害给河南省信阳市的茶叶产业造成了巨大损失。为掌握该市茶叶具体受灾情况,笔者对该市的茶叶产业雨雪冰冻灾害损失进行了专题调研,分别对该市的新老茶园进行了实地调查,掌握了本次雨雪冰冻灾害对该市茶叶产量和品质的影响情况,提出了相应的经营措施,以期对下一步恢复重建,减少茶农经济损失,应对类似灾害极早采取相应有效措施提供一定依据。     

受雨雪冰冻灾害林木资源资产评估方法的探讨

以雨雪冰冻灾害的林木资源资产为研究对象,根据福建省地方标准《森林资源资产评估技术规范》和《福建省雨雪冰冻灾害森林资源损失调查评估操作细则》等有关规定,在深入调查受雨雪冰冻灾害的林木资源资产基础上,提出受灾林木的林木资源资产评估方法,为较准确地评估受灾林木的林木资源资产价值提供科学依据,以确保林木资源资产出让、作价出资合作等经济行为顺利开展。     

雨雪冰冻灾害对江西大岗山森林水文效应的影响

以江西大岗山地区的常绿阔叶林、杉木林(Cunninghamia Lanceolata)、毛竹林(Phyllostachys pubescens)等3种林型为研究对象,对比分析了其主要水文生态效应在雨雪冰冻灾害前(2006年)与灾害后(2010年)的变化。结果表明:雨雪冰冻灾害造成常绿阔叶林、杉木林、毛竹林3种林型林内降雨量增加,相比雨雪冰冻灾害前各林型的树干径流率、穿透雨率都有所增大,截留率变小,其中阔叶林的树干径流率、穿透雨率和树冠截留率变化幅度最大,毛竹林的变化幅度最小;3种林型地上枯落物增厚和蓄积量增多,枯落物持水量和截留能力也相应增大;雨雪冰冻灾害后3种林型土壤主要水分物理性质和主要水文效应变化较小,这可能与土壤在枯落物下层未直接受到雨雪冰冻灾害破坏有关。     

贵州省灾后重建及配套政策调研报告

一、贵州省及省级林改试点县遭受冰冻雨雪灾害情况 （一）全省林业受灾情况。2008年1月12日以来,贵州省遭遇了有气象记录以来最为严重的冰冻雨雪灾害,是贵州境内持续时间最长、影响范围最大、灾情最严重的一次自然灾害,给全省各行各业和人民群众的生产生活带来严重影响,造成巨大损失。尤其是林业在这次灾害中,受到影响的时间更长、范围更广,经济损失更为惨重。据统计,在这次特大冰冻雨雪灾害中,     

Stem damage in Swiss forests: incidence,causes and relations to crown transparency

In the annual assessments of forest damage in Switzerland, the nature of any stem damage is recorded on the target trees. As the inventory is undertaken on a representative basis, the extent of stem damage should accurately reflect the extent of stem damage on trees in Switzerland. This paper examines the occurrence of stem damage by species, region and forest type and determines whether any relationship exists between stem damage and crown transparency.     

沥青路面水损害及其防治

沥青路面水损害问题是公路工程质量通病之一。本文从水损害产生的原因入手 ,对沥青路面水损害的产生进行了较详细的机理分析 ,并针对性地提出了预防水损害出现的相应措施。     

A statistical algorithm for comparing mode shapes of vibration testing before and after damage in timbers

Instances of local damage in timber such as knots, decay, and cracks can be translated into a reduction of service life due to mechanical and environmental loadings. In wood construction, it is very important to evaluate the weakest location and to detect damage at the earliest possible stage to avoid future catastrophic failure. In this study, modal testing was used on wood beams to generate the first two mode shapes. A novel statistical algorithm was proposed to extract a damage indicator by computing mode shapes of vibration testing before and after damage in timbers. The different damage severities, damage locations, and damage counts were simulated by removing mass from intact beams to verify the algorithm. The results showed that the proposed statistical algorithm is effective and suitable for the designed damage scenarios. It is reliable for the detection and location of local damage of different severities, location, and number. The peak values of the damage indicators computed from the first two mode shapes were sensitive to different damage severities and locations. They were also reliable for the detection of multiple cases of damage.     

Wind and snow damage in a thinning and fertilization experiment in Picea abies in southern Sweden

Changes in susceptibility to wind and snow damage due to thinningand fertilization were examined in even aged Norway spruce (Piceaabies (L.) Karst.) stands in southern Sweden. The stands arepart of a nationwide experiment to investigate growth and yieldfollowing different thinning and fertilization regimes establishedbetween 1966 and 1983. The material used in this study included16 replications of seven treatments. The treatments were: threelevels of thinning from below (20–70 per cent); 20 percent thinning from above; thinning from below in combinationwith N and NP fertilization (thinning percentage 25–28per cent); and unthinned control. The stands have been censusedtwice for damage during an average period of 12 years. The degree of wind and snow induced damage varied between 9and 20 per cent of the basal area increment produced duringthe observation period. For treatments with high basal arearemoval, the highest relative number of trees damaged by windoccured during the first period after thinning. The denseststands (i.e. unthinned controls and stands thinned from above)showed a high proportion of snow damage throughout the observationperiod. The block effect was in general more significant thanthe effect of treatments on damage level. When analysing theinfluence of the block effect (i.e. of site and stand characteristics)on damage level, wind damage was best predicted by stand basalarea left after thinning and stand age, while snow damage wasbest predicted by latitude, altitude, site index, and standage. On average the tested site and stand characteristics explained17 per cent of the variation in wind damage and 36 per centin snow damage.     

木材损伤断裂与木材细观损伤基本构元

木材承载时细观结构上的损伤会在木材中扩展,并且损伤和缺陷在载荷下的演化行为决定着木材的宏观力学行为.木材的细观损伤基元可以归纳为4类:1)胞、壁层间界面损伤;2)细胞壁屈曲与局部塌溃损伤带;3)微孔洞损伤与汇合;4)微裂隙损伤(区).追踪分析木材从变形、损伤到断裂破坏的全过程,探明微结构演化与宏观行为关系,有助于揭示木材破坏的机制,并从中获得新的木材构造与其强韧功能相互关系的认识,对研发能够克服木材缺点、具有特殊强韧性能的新型木基复合材料具有重要指导意义.     

Feral swine damage and damage management in forested ecosystems

Invasive feral swine (Sus scrofa) cause deleterious impacts to ecosystem processes and functioning throughout their worldwide distribution, including forested ecosystems in the United States. Unfortunately, many feral swine damage management programs are conducted in a piecemeal fashion, are not adequately funded, and lack clearly stated or realistic objectives. This review paper identifies damage caused by feral swine to forest resources and presents techniques used to prevent and control feral swine damage. Concluding points related to planning a feral swine damage management program are: (1) the value of using a variety of techniques in an integrated fashion cannot be overstated; (2) there is value in using indices for both feral swine populations and their damage pre and post management activities; (3) innovative technologies will increasing be of value in the pursuit of feral swine damage reduction; and (4) though not appropriate in every situation, there is value in involving the public in feral swine damage management decisions and activities.     

Vegetation and weather explain variation in crown damage within a large mixed-severity wildfire

The 2002 Biscuit Fire burned through more than 200,000 ha of mixed-conifer/evergreen hardwood forests in southwestern Oregon and northwestern California. The size of the fire and the diversity of conditions through which it burned provided an opportunity to analyze relationships between crown damage and vegetation type, recent fire history, geology, topography, and regional weather conditions on the day of burning. We measured pre- and post-fire vegetation cover and crown damage on 761 digital aerial photo-plots (6.25 ha) within the unmanaged portion of the burn and used random forest and regression tree models to relate patterns of damage to a suite of 20 predictor variables. Ninety-eight percent of plots experienced some level of crown damage, but only 10% experienced complete crown damage. The median level of total crown damage was 74%; median damage to conifer crowns was 52%. The most important predictors of total crown damage were the percentage of pre-fire shrub-stratum vegetation cover and average daily temperature. The most important predictors of conifer damage were average daily temperature and “burn period,” an index of fire weather and fire suppression effort. The median level of damage was 32% within large conifer cover and 62% within small conifer cover. Open tree canopies with high levels of shrub-stratum cover were associated with the highest levels of tree crown damage, while closed canopy forests with high levels of large conifer cover were associated with the lowest levels of tree crown damage. Patterns of damage were similar within the area that burned previously in the 1987 Silver Fire and edaphically similar areas without a recent history of fire. Low-productivity sites on ultramafic soils had 92% median crown damage compared to 59% on non-ultramafic sites; the proportion of conifer cover damaged was also higher on ultramafic sites. We conclude that weather and vegetation conditions — not topography — were the primary determinants of Biscuit Fire crown damage.     

北美红杉种植点白蚁为害状况及其防治初报

经对北美红杉各种植点白蚁为害状况的调查分析结果表明,白蚁为害随着海拔高度的增加而减少,但不明显,以1200～2000m为害严重,2100m以上均无白蚁为害,北美红杉造林后,以当年受害为主,与造林苗大小无关,6月造林较1月造林受害严重。采用3%呋喃丹防治,用量每株10g,总体防效可达66 63%～95 25%,其中防效最好的是屏边县大凹腰3个试验点。另外,12月和1月造林防效较好,6月造林防效最差,仅为68 75%。     

海南省槟榔红脉穗螟危害情况调查

红脉穗螟Tirathaba rufivena Walker是槟榔花果期的主要害虫,对槟榔产量影响较大。对海南主要槟榔产区红脉穗螟危害情况的调查结果表明:槟榔平均单株受害率16.89%,在坡地的危害程度要大于平地和水田地;三亚、保亭和陵水地区的危害程度要大于北部的琼海、万宁和屯昌地区。     

Wind Damage to the Leaves of Sycamore (Acer pseudoplatanus L.) in Coastal and Non-coastal Stands

Wind damage to the leaves of sycamore (Acer pseudoplatanus L.)trees was examined at five sites in Northern Ireland duringJune and September, 1986 by estimating the percentage of leafarea showing lesions, discoloration or actual loss of laminasurface. Levels of damage on individual leaves ranged up to 46.6 percent of the leaf area but few leaves had damage greater than10 percent. Two sites showed relatively low levels of damage(about 2 per cent of lamina damaged); one site was inland, andthe other, although coastal, was well sheltered. The three othersites had damage in excess of 3.5 per cent of the lamina area—thesite with the highest levels of damage being the most exposedsite and the one probably experiencing the greatest amount ofturbulence. Most damage had occurred by June and there was littleincrease in damage levels between the June and September samples;there was however evidence of the premature loss of the mosthighly damaged leaves. Regression analysis indicated that at sites showing the highestlevels of damage, the most highly damaged leaves were the smallest.It is argued that in these cases the damage to the leaves issufficiently high to prevent full leaf expansion. At sites wherethe overall damage levels were lower, there was either a non-significantrelationship between percentage leaf damage and leaf area ora significant positive relationship. It is suggested here thatthe damage levels are not great enough to inhibit the expandingleaves reaching full size.