Can predicted mountain pine beetle net production be used to improve stand prioritization for management?

Stand-level planning of lodgepole pine management can benefit from the use of mountain pine beetle susceptibility-risk model analyses to assign treatment priority. Priority is currently assigned based solely on relative levels of expected volume loss in the event of a mountain pine beetle outbreak. We evaluated the possibility to predict the relative contribution of brood beetles, by infested stands, to the next beetle generation. Existing data were used to develop generalized parameters for inclusion in predictive models of stand-level mortality and brood production. Model output for independent stands achieved a highly significant relationship with measured outcomes of brood productivity, indicating that relative levels of brood production can be predicted and incorporated into decision-models.     

Effects of mountain pine beetle (Dendroctonus ponderosae Hopkins) infestations on forest stand structure in the southern Canadian Rocky Mountains

Forests in the montane and lower subalpine ecoregions of the southern Canadian Rocky Mountains may have been more open and structurally diverse at the beginning of the 20th Century than today. Today, the area of mature Pinus contorta subsp. latifolia Dougl. forest that is conducive to mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins) infestations, infrequent high severity fires, and herbivory appears to have increased in Banff and Kootenay National Parks. Based on a review of the literature, we hypothesised that MPB infestations increase forest stand structural diversity and tree species diversity. Stand structure parameters were investigated in mesic montane and lower subalpine stands approximately 15, 25, and 65 years after MPB outbreaks. Parameters measured were stand density (number of trees per ha), diameter at breast height, height class, species, age class distribution, and coarse woody debris mass. Influences of fire frequency, time since fire, and fire severity on these parameters were assessed to determine whether fire history had a confounding influence on stand structure. The Shannon–Wiener index indicated higher stand structural diversity 15 years but not 25 and 65 years after MPB infestations. MPB infestations led to general decreases within stands in the number of living trees, small diameter snags, and Pinus tree species and an increase within stands in the number of large diameter snags. Management that allows the occurrence of the natural fire regime of variable severity fires, in addition to some MPB infestations, would provide for more open and diverse stands. MPB infestations have some effects on stand structure that are similar to those of fire. Changes in stand structure resulting from recent declines in burning rates within Banff and Kootenay National Parks can be reversed to some extent by MPB infestations.     

Pathogens and parasites of adults of the great spruce bark beetle, Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae, Scolytinae) from Turkey

In this study, the pathogen and parasite spectra of Turkish populations of the great spruce bark beetle Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae, Scolytinae) are analysed. In addition to the previously studied infective green alga Helicosporidium, three more pathogens and parasites, i.e. the yeast Metschnikowia sp., the neogregarine Mattesia sp. and a nematode, were recorded here for the first time. The pathogens and parasites occur in different quantities and combinations in outbreaks of the beetle at five Turkish localities.     

神农架林区华山松大小蠹扩散规律研究

为摸清神农架林区华山松大小蠹扩散规律。查阅了华山松大小蠹侵害的本底资料,分析了华山松大小蠹的发生趋势,研究了华山松大小蠹危害和海拔、年均高、低温的关系。结果表明:神农架林林区中西部,特别是高海拔地区危险性高,海拔1 822 m以上区域华山松大小蠹发生严重,海拔高度和疫情受害面积呈现正相关,拟合方程为Y=657.571 43+374.119 05 X-30.238 1 X~2,相关系数R~2为0.927 04,但不显著;年均高、低温和华山松大小蠹危害面积表现出相同的线性关系,年均低温在7~9℃,年均高温在16~20℃呈现正相关,多项式拟合方程Y=4.656 18E9-4.626 45E6 X+1 149.22685 X~2,相关系数为0.871 89。     

诱捕器的空间位置对红脂大小蠹防治效果的比较研究

针对辽宁省区域内出现的红脂大小蠹,研究了诱捕器不同挂置高度、放置坡位和颜色等3个因素对诱捕效果的影响。结果表明:挂置高度方面,2m的高度处理平均诱捕量最高;放置坡位方面,山腰处放置处理平均诱捕量最高;诱捕器颜色方面,红色的诱捕器处理平均诱捕量最高。     

芦芽山保护区红脂大小蠹生物学特性及防治研究

红脂大小蠹(Dendroctonus valens)于1999年首次在芦芽山地区发现危害油松林,1999年9月至2004年12月对本区红脂大小蠹的生物学特性及防治技术进行了研究。结果表明:红脂大小蠹在本区主要以老熟幼虫、二龄以上幼虫及成虫在主、侧根的虫道内或土层中的干基部分越冬。成虫于5月上中旬开始出孔扬飞,6月初开始产卵,初孵幼虫始见于6月中旬,8月上旬为化蛹始期,8月中旬成虫开始羽化,10月上中旬以各种虫态进入越冬状态。卵历期11 d~15 d,幼虫历期45 d~55 d,蛹期11 d~13 d。综合防治方法主要分越冬期防治、危害期防治、利用天敌防治和采取营林措施。     

华山松大小蠹的一种高效引诱剂

华山松大小蠹Dendroctonus armandi Tsai et Li是危害我国华山松Pinus armandii的主要蛀干害虫。收集和测定华山松树皮和华山松大小蠹的挥发物,根据挥发物组分设计配制8种诱芯,采用漏斗诱捕器进行林间诱捕筛选试验;应用诱芯Ⅱ进行多点诱捕验证和有效诱捕距离试验。结果表明:诱捕期内,诱芯Ⅱ平均诱捕华山松大小蠹1 070头/诱捕器,显著高于其它7种诱芯;单个诱捕器一天最多诱捕1 652头。诱芯Ⅱ在3个地点的平均诱捕量差异不显著,分别为83,114,101头/诱捕器,诱捕效果不存在地理差异;距离林缘50 m处诱捕量为43.5头/诱捕器,为最佳有效诱捕距离。该华山松大小蠹高效引诱剂可为我国华山松大小蠹的治理提供新技术。     

神农架林区华山松大小蠹危害风险分析

利用景观生态学的研究方法,以神农架林区华山松大小蠹Dendroctonus armandi为研究对象,从华山松Pinus armandii景观空间格局分析林区华山松大小蠹发生情况,并对林区各林场乡镇的风险程度进行分析.结果表明:华山松大小蠹发生与寄主华山松的面积分布占比、斑块密度呈正相关,相关系数R值分别为0.504和...     

华山松集体人工林抚育间伐探索

为探索华山松集体林抚育间伐的强度、组织形式和管理办法。通海县林业局1995年开始在九街镇香箐头对1988年栽植的华山松幼林进行抚育间伐试验。在试验中引入市场竞争机制，实行招投标制，辅以科学规划，现场培训。加强监督，达标验收，收支结算等措施，取得了工效提高8倍的效果，并进行了讨论。     

华山松种子园针叶养分状况的研究

通过对华山松种子园内无性系针叶养分状况的分析,结果表明,无性系之间的营养元素含量差异极显著,尤其表现在Ｃａ,Ｋ营养上,而针叶的元素含量顺序为Ｎ,Ｃａ,Ｋ,Ｍｇ,Ｐ,Ｍｎ,Ｆｅ,Ｚｎ,Ｂ;不同月龄针叶养分含量差异极大,未完全抽长针叶养分含量顺序为Ｎ,Ｋ,Ｃａ,Ｍｇ,Ｐ。针叶内微量元素含量与无性系有较大相关性,而不同土壤上华山松针叶微量元素的含量差异更大,尤其是针叶Ｂ的含量,因此土壤施Ｂ可在针叶的含量