九寨沟华山松枯死原因的研究——枝枯病病原菌种类的研究

通过对九寨沟华山松1 a生和2 a生发病枝梢组织分离培养结果,1 a生发病枝梢优势茵株为拟菌点霉属(Phomopsis sp.),2 a生枝梢优势茵株为壳蕉孢属(Cytospore sp.).将两种优势菌株用刺伤法分别在室内、林间接种试验,两种菌株均能使华山松新梢发病枯死,出现的症状完全与自然发病相同.并将发病枝梢再分离,得到同样的接种茵株.初步确定引起华山松枝枯病优势病原茵为拟茵点霉属和壳蕉孢属,属于两种病原茵混合侵染性病害.     

岷江上游油松与华山松人工混交林对降雨的截留分配效应

人工油松与华山松混交林是岷江上游区域主要的群落类型，采用水量平衡的方法，研究了混交林林冠截留量、穿透量、树干茎流量等指标。通过混交林对24场降雨分配的定位观测，结果表明林冠截留量83．47mm、穿透量81．43mm、茎流量2．00mm，分别占同期降雨量的50．o％，48．8％，1．2％；幂函数方程能较好地拟合林冠截留量与林外降雨量之间的关系，而线性方程能较好地拟合穿透雨量、树干茎流量和林外降雨量之间的关系。结果表明恢复重建后的人工油松与华山松混交林生态系统在水源涵养、水土保持上效果明显。     

Southern pine beetle regional outbreaks modeled on landscape, climate and infestation history

The southern pine beetle (Dendroctonus frontalis, SPB) is the major insect pest of pine species in the southeastern United States. It attains outbreak population levels sufficient to mass attack host pines across the landscape at scales ranging from a single forest stand to interstate epidemics. This county level analysis selected and examined the best climatic and landscape variables for predicting infestations at regional scales. The analysis showed that, for a given county, the most important factor in predicting outbreaks was that the county was classified as in outbreak status in the previous year. Other important factors included minimum winter temperature and the greatest difference between the average of daily minimums and a subsequent low temperature point, precipitation history either seasonally in the previous year or difference from average over the previous 2 years, the synchronizing effect of seasonal temperatures on beetle populations and the relative percentage of total forest area composed of host species. The statistical models showed that climatic variables are stronger indicators of outbreak likelihood than landscape structure and cover variables. Average climatic conditions were more likely to lead to outbreaks than extreme conditions, supporting the notion of coupling between a native insect and its native host. Still, some extreme events (i.e., periods of very low temperature or very high precipitation) did precede beetle infestation. This analysis suggested that there are predisposing and inciting factors at the large scale but the driving factors leading to individual infestations operate at smaller scales.     

我国红脂大小蠹生物学与防治研究概况

红脂大小蠹(Dendroctonus valens)是近年严重危害我国北方油松林的森林害虫。本文总结了5a来我国红脂大小蠹的生物学和防治方法研究进展,建议在防治红脂大小蠹时,应加强检疫工作,防止扩散,加强天敌利用工作,大力发展信息素防治法,同时积极研究新的化学防治方法。     

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     

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。     

华山松大小蠹对华山松韧皮部营养和矿物元素的利用

对健康和蓝变真菌侵染的华山松韧皮部以及华山松大小蠹排泄物中粗蛋白、粗脂肪、粗纤维、淀粉、还原性糖、可溶性总糖、游离态氨基酸和Na,K,Ca,Mg,Fe,Cu,Mn,Zn等8种元素进行分析,结果表明:华山松大小蠹对寄主华山松营养物质的利用率依次为:还原性糖＞粗脂肪＞可溶性总糖＞粗纤维＞淀粉＞粗蛋白.华山松韧皮部的17种游离态氨基酸中含有华山松大小蠹必需的9种氨基酸;华山松大小蠹对寄主华山松韧皮部组织内的Na,K,Ca,Mg,Fe,Cu,Mn,Zn等8种矿物元素需求量存在明显差异,其中对K元素的需求量最大,而对Cu,Mn,Zn 3种元素的需求量较小.同时,华山松大小蠹共生真菌能够加速华山松木质部和韧皮部中营养的分解转化,为华山松大小蠹在被害华山松韧皮部和木质部间的生存和发育创造条件,并加速被害华山松树势的衰弱和死亡.     

川东华山松死亡原因探讨 Ⅰ.酸雨

本文就酸雨与四川东部华山松大面积枯死的关系进行了论证。华山松严重发病区巫山县梨子坪林场5-8月份大气降水的pH值分别为6.06、5.80、6.05、5.78;土壤pH值为5.20-6.65。用pH为3.5、4.5、5.5的稀硫酸模拟酸雨试验,喷雾200 h、400 h后对华山松的生长量、干重、叶绿素含量无不良影响,实验证明四川东部华山松大面积枯死与酸雨无关。     

Woodpeckers increase in abundance but maintain fecundity in response to an outbreak of mountain pine bark beetles

Many temperate woodpecker species are thought to be highly conservative in their fecundity with little response to fluctuations in availability of resources. In a 15-year field study in interior British Columbia, we evaluated responses in abundance and fecundity of six species of resident and migrant woodpeckers (downy woodpecker [Picoides pubescens], hairy woodpecker [Picoides villosus], American three-toed woodpecker [Picoides dorsalis], pileated woodpecker [Drycopus pileatus], northern flicker [Colaptes auratus], and red-naped sapsucker [Sphyrapicus nuchalis]) to a large-scale outbreak of mountain pine bark beetles that resulted in a strong positive pulse in food supply. Population densities of woodpecker species increased during outbreak years. Despite the year-round multi-annual increase in food resources, and in contrast to the strong increases in fecundity shown by nuthatches and chickadees, annual fecundity (as indicated by clutch size and number of nestlings that fledged) did not change for any woodpecker species over the study. Similarly, we found no changes in fecundity in response to selective forest harvesting despite numerical increases for woodpeckers at these sites. Our study confirms that these woodpecker species are conservative in their reproductive investment patterns even during strong multi-annual increases in food. Our findings indicate woodpecker populations are regulated numerically through variable survival and/or greater immigration rates, which can result in higher breeding densities temporarily during resource pulses.     

氧化乐果与敌敌畏乳油混剂防治华山松大小蠹试验报告

选择初侵染木作为防治对象,使用农药氧化乐果与敌敌畏乳油混剂(1),采取打孔注药法对华山松树体内大小蠹虫进行了防治试验.结果表明,施药浓度为30-35倍液,其杀虫率可达85%以上,防治效果较好.