湖南四水流域适宜森林覆盖率指标研究

以湖南省湘江、资江、沅江和澧水四大流域为研究对象,探索在大尺度上森林覆盖率对水文效应的影响.通过编制水文特征值得分表和精度检验,确定了径流深(y1)、相对河况系数(y2)、河流含沙量(y3)、侵蚀模数(y4)4个水文因子和森林覆盖率(X1)、水利工程数量(X2)、流域形状系数(X3)、平均坡度(X4)、流域面积(X5)、年降雨量(X6)6个流域因子,并建立了它们之间的关系模型,并求出流域在其它因子一定时的该水文因子所要求的适宜森林覆盖率,综合考虑各水文因子在水文生态环境中的相对重要性并进行加权平均,确定流域内适宜森林覆盖率指标分别为:湘江49%,资江47%,沅江51%,澧水50%.     

国营林场抚育间伐伐区工艺设计诸问题研探

本文对抚育间伐伐区工艺设计中的采伐类型、伐区等级、间伐强度、作业定额、设计表的研究提出探讨意见。     

昌宁县华山松数量化立地指数表编制

林业生产中,不仅需要评定有林地的立地质量,也需要对无林地的立地质量进行评价,以便合理利用土地,为充分发挥宜林地的生产潜力和适地适树进行造林提供科学依据。为此利用标准地主要环境因子与其地位指数间的相关关系,编制此表,作为评价森林立地质量、预测林地生产力、造林规划设计、森林经营管理等重要依据。编表方法是利用地形、土壤等主要因子为自变量,按地位指数表查定各标准地的地位指数作为因变量,采用数量化理论(Ⅰ)求解,编出标准年龄时华山松立地指数得分表。     

马尾松古松叶蜂的研究

马尾松吉松叶蜂（ＧｉｌｐｉｎｉａｍａｓｓｏｎｉａｎａＸｉａｏ）属松叶蜂科Ｄｉｐｒｉｏｎｉｄａｅ，是危害马尾松的一种新害虫，近年来在安徽滁县沙河集林业总场发生相当严重。经研究，此虫一年发生２代，以预蛹越冬。该幼虫的空间分布型为聚集分布，我们编制了“马尾松吉松叶蜂地面茧数”查定表；制定了防治指标；其防治适期为２—３龄幼虫出现高峰期：第１代为５月１５－３０日；第２代为１０月１０—２５日。以２．５％溴氰菊酯乳油２０００—５０００倍液等进行喷雾防治，效果均在９４％以上；以２．５％溴氰菊酯乳油等加柴油配成油烟剂进行喷烟防治，效果在９６％以上。     

杨潜叶跳象生物学特性及防治方法的初步研究

杨潜叶跳象Rhynchaenus(Tachyerges)empopulifolis Chen属鞘翅目(Coleoptera)象甲科(Curculionidae)跳象亚科(Rhynchaeninae),是笔者近几年发现的为害杨树的一种新害虫。1983—1986年,我们在喀左县关大海乡和水泉乡对此中进行了较系统的研究,现将结果报道如下。     

食物对兹沃尔新小绥螨生长发育和繁殖的影响

为探究不同食物对兹沃尔新小绥螨Neoseiulus zwoelferi种群生长、发育和繁殖的影响,采用年龄-龄期两性生命表分析测定兹沃尔新小绥螨取食卢氏叶螨Tetranychus ludeni、甜果螨Carpoglyphus lactis和香蒲Typha orientalis花粉后的存活率、发育历期、寿命及繁殖情况。结果显示,3种食物均能满足兹沃尔新小绥螨生长发育和繁殖的需求。卢氏叶螨处理组的净增殖率和总繁殖率分别是28.99和36.99,均显著高于其他2个处理组;以甜果螨、卢氏叶螨和香蒲花粉为食的兹沃尔新小绥螨从卵发育至成螨所需时间分别为5.28、7.34和6.87 d,种群倍增时间分别3.35、4.22和11.77 d,前者显著短于其他2个处理;甜果螨处理组和卢氏叶螨处理组的雌成螨平均寿命分别比香蒲花粉处理组长2.75 d和4.92 d,但两者之间无显著差异;卢氏叶螨处理组雌成螨产卵天数最长,为17.84 d,产卵前期时间最短,为2.75 d,产卵量最大,为38.15粒/雌;香蒲花粉处理组雌成螨产卵天数最短,仅1.82 d,产卵前期时间最长,为5.89 d,产卵量最少,为3.36粒/雌。甜果螨处理组的内禀增长率、周限增长率分别为0.21 d-1和1.23 d-1,均显著高于其他处理组,但平均世代周期为14.65 d,显著低于其他处理组。表明3种食物均可使兹沃尔新小绥螨完成整个世代,其中甜果螨是室内饲养兹沃尔新小绥螨的最佳食物,香蒲花粉可以作为短期饲养的食物。     

Community Stability Was Maintained by Divergent Mechanisms in Arid Desert Ecosystem

More attention has been paid to the effects of diversity and dominance on community temporal stability rather than spatial stability in the main biome globally. Moreover, the maintenance mechanisms underlying the stability patterns of plant communities dominated by different plants in the Gobi Desert remain unknown. This article addresses the maintenance mechanism of plant community stability dominated by different plants in the Gobi Desert northwest of China. Four communities dominated by Sympegma regelii, Reaumuria songarica, Nitraria sphaerocarpa, and Gymnocarpos przewalskii, respectively, were selected in the national nature reserve, and a total of 240 quadrats, 20 × 20 m each, were established in the four communities. The correlations among species richness, species evenness, species diversity, community stability, and the biomass of dominant species were analyzed by linear regression model and structural equation model. The dominant species determined positively and directly the stability of the N. sphaerocarpa community, while diversity acted negatively in the maintenance of G. przewalskii community stability. However, species richness contributed mainly and positively to the maintenance of stability in the S. regelii community. Direct and negative effect of species richness and positive function of diversity were found in the maintenance of stability in the R. songarica community. Taken together, community stability is maintained by the divergent mechanisms in arid environment, which depends on the dominant species and diversity. The study could provide reference for the management of communities in the arid desert regions.     

RCB-20无级变速高效秸秆揉搓机研制

为了克服中小型秸秆揉搓机转子速度不能调整的问题,研究设计了RCB-20型无级变速揉搓机.该机锤片末端线速度能在45～70 m/s范围内任意调节,基本上涵盖各种揉搓机锤片末端的线速度,能够根据不同的物料,选用合理的速度,确保物料的加工品质,还能充分发挥机器效能、延长机器使用寿命.生产率可达3～6 t/h.     

Estimating the net carbon balance of boreal open woodland afforestation: A case-study in Québec’s closed-crown boreal forest

Black spruce (Picea mariana (Mill.) B.S.P.) is the dominant tree species in the Canadian province of Québec’s boreal ecosystem, particularly in the black spruce-feathermoss (BSFM) domain (between the 49th and the 52nd parallels). While black spruce is generally well adapted to regenerate after wildfires, regeneration failure can sometimes occur, resulting in the irreversible conversion of closed-crown BSFM to open black spruce-lichen woodlands (OW). With OWs representing approximately 7% (1.6 M ha) of Québec’s BSFM domain, the afforestation of OWs carries significant theoretical potential for carbon (C) sequestration, which has not yet been evaluated. The main objectives of the study were then: (i) to estimate the theoretical C balance of OW afforestation within the closed-crown BSFM domain in Québec’s boreal forest; (ii) to calculate, using the life cycle analysis (LCA) method, all the GHG emissions related to black spruce OW afforestation in the closed-crown BSFM domain of Québec. The CO2FIX v. 3.1 model was used to calculate the biological C balance between the baseline (natural OW of site index 9 at age 50) and afforestation (black spruce plantation of site index 6 at age 25) scenarios, using the best estimates available for all five recommended C compartments (aboveground biomass, belowground biomass, litter, deadwood, and soil). The simulation revealed a biological C balance of 77.0 t C ha⁻¹, 70 years following afforestation, for an average net sequestration rate of 1.1 t C ha⁻¹ year⁻¹. Biological C balance only turns positive after 27 years. When integrating the uncertainties related to both the plantation growth yield and the wildfire disturbance, the average sequestration rate varies between 0.2 and 1.9 t C ha⁻¹ year⁻¹. GHG emissions are 1.3 t CO₂ equiv. ha⁻¹ for all afforestation-related operations, which is less than 0.5% of the biological C balance after 70 years. Thus, GHG emissions do not significantly affect the net C balance of the afforestation project simulated. Several recommendations are made, mostly centered on the factors influencing the growth rate of carbon stocks and the impact of natural disturbances, to minimize the range of uncertainties associated to the sequestration potential and maximize the mitigation benefits of an OW afforestation project.     

转基因741杨林中靶标害虫实验种群生命表研究

通过在转基因741杨林中,对靶标害虫舞毒蛾实验种群生命表的比较研究,证明转基因741杨林中舞毒蛾世代存活率与对照相比显著降低,种群趋势指数降低了82%～92%,表明转基因杨可以减少靶标害虫的自然种群数量.经存活曲线分析得知舞毒蛾种群的个体死亡主要发生在幼龄幼虫期,特别是对1,2龄幼虫的致死能力更为明显.经过对转基因741杨林中舞毒蛾各死亡因子的致死力比较分析可知:由毒蛋白直接引起的食物和环境共同作用、病菌致死以及间接引起的化蛹死亡率升高的最为明显,转基因741杨林中舞毒蛾各龄期幼虫寄生性天敌的寄生率较之未转基因林下降.