道路涎流冰防治浅议

通过在西藏4年多的公路勘察设计，认识了涎流冰的形成及对道路的危害，了解了一些对涎流冰的防治措施，现对涎流冰的防治提出一些粗浅的看法，供设计参考。     

浅谈林区公路涎流冰病害及处理

涎流冰是林区公路的常见病害，它的形成与很多因素有关，由于各种因素的不同而产生了不同类型、规模的涎流冰，该文探讨了涎流冰的形成条件、类型特征及几种常见的治理方法。     

涎流冰的形成与防治

涎流冰是我国三北(东北、西北、华北)地区道路的主要冻害之一。以东北地区尤为严重(特别是大小兴安岭地区)。本文根据作者多年对公路涎流冰的观测、调查、研究、找出了涎流水形成的主要原因。并总结了涎流冰的防治措施和治理办法。比较有效的解决了涎流冰对道路的危害问题。     

羌塘高原冻土区公路山坡涎流冰形成与对策分析

在羌塘高原冻土区特殊的地理、水文和气候因素条件下,形成的山坡涎流冰对穿过的公路有极大危害。从高寒地理气候区概况、影响因素和病害特征切入,综合冻结-压力理论和冻土物理学分析土中水的迁移机制,探讨涎流冰形成过程。通过土中水的分布特征预测涎流冰出现区域,归纳涎流冰病害整治措施。     

林区公路涎流冰的形成与防治

1989年冬我们林区公路病害调查组,在黑龙江省牡丹江、牙克石林区进行了公路涎流冰的实地调查,现将调查情况汇总如下,以供参考。一、涎流冰分布情况涎流冰是黑龙江省地方公路及林区公路的一种严重病害。全省冬季气候严寒:兴安山地最冷月平均气温-22℃以下,最低气温     

冰湖的产生和治理

１冰湖产生的条件及原因１．１条件水源：形成涎流冰的水源主要是浅层地下水，它是形成冰湖的内因，是必要条件。负温及寒冷的气候：当地下水在挖方边坡或地表薄弱处溢出涎流时，在负温下结冰就形成了涎流冰，涎流冰体逐渐增大就成为冰湖。地形地质条件：冰湖多产生在山坡...     

林区公路涎流冰治理技术的研究

公路涎流冰是冻土地区独特的工程地质现象-称为冰椎,我国北方统称冰湖,对公路运输危害十分严重。为取得多年冻土地区林区涎流冰的发生发育规律,大兴安岭林管局、黑龙江省木材采运研究所、哈尔滨建工学院、呼中林业局、西     

涎流冰防治工程及试验效果分析

涎流冰又称冰椎、冰湖,是多年冻土地区独特的工程地质现象。在我国大小兴安岭、长白山、新疆等地均有发育。青藏高原4200米以上地区也有出露。涎流冰对公路的危害十分严重,轻则降速、陷车,重则翻车伤人,严重影响线路的正常运营,同时养护耗资巨大,据83年调查,仅大兴安岭地区     

林区公路翻浆产生的原因和防治措施

论述了福建林区公路翻浆现象的危害性和形成原因,提出防治林区公路翻浆问题的主要措施。     

大兴安岭林区冰湖病害的防治

简要阐述了大兴安岭地区冰湖形成的原因,并提出了林区公路冰湖的具体防治技术,以保障林区公路畅通无阻.     

丽江老君山黎明谷露营地规划方法探讨

以丽江老君山黎明谷露营地为案例进行了研究,通过对黎明谷的现状分析,对露营地的选址、功能分区、交通规划、景观规划、给排水和电力规划以及相关旅游服务设施规划等方面进行了深入探讨,阐述了露营地规划设计方法。     

内蒙古桦木沟地区野生花卉资源开发利用研究

通过对桦木沟自然保护区植物资源的调查及其自然环境分析,结合其植物区系特点,介绍当地极具特色的野生花卉资源及其园林应用,这些野生花卉在花形、花色上具有鲜明的特征,同时赋有中国文化特色,是花卉育种的重要物质基础。另一方面,现在已经建立了金莲花保护基地、二色补血草生产基地,但总体开发缺少科学指导,数量质量都开发较少,通过调查研究分析,对开发现状、存在的问题和将来的引种工作等提出了建议,以便进一步合理开发利用。     

喜马拉雅山底雅段和札达段蚂蚁多样性

为揭示喜马拉雅山蚂蚁群落的生态学规律,采用样地调查法对喜马拉雅山底雅段和札达段的蚂蚁群落进行调查。共观察蚂蚁5355头,隶属于2亚科5属7种,其中底雅段7种,札达段3种。对该地区蚂蚁物种丰富度进行估计,结果表明底雅段和札达段的蚂蚁物种丰富度较低。底雅段南坡的蚂蚁物种数目、Shannon-Wiener多样性指数、Fisherα指数和优势度指数表现出"中域效应"现象,而个体密度则表现出"多域效应"现象;札达段南坡的蚂蚁物种数目、个体密度和Fisherα指数均表现出"多域效应"现象。蚂蚁群落相似性系数显示各样地间的蚂蚁群落处于极不相似至极相似水平,表明该地区不同海拔蚂蚁群落既有差异又存在一定共性。在底雅段和札达段,海拔对蚂蚁物种的分布和多样性有较大影响,坡向和植被对蚂蚁群落分化有重要作用。     

叶用银杏半同胞家系苗期性状生长动态及苗期选择

对银杏2年生苗苗高、地径生长过程运用Logistic方程进行模拟，相关系数均在0．97以上，银杏高生长在萌芽展叶后直接进入速生期，地径生长速生期开始与结束均要晚于苗高生长速生期，不同家系苗高、地径生长速生期的停止期差异较大。银杏苗期叶片的叶长、叶宽、单叶干重、单叶鲜重、平均单叶面积等形态指标的年生长节律呈S型曲线、内含物的年变化规律呈双峰型曲线。研究表明：苗高与地径生长的速生期终点、成熟健康叶片的叶面积、9月初的叶片总内酯含量、9月底的叶片总黄酮含量等性状可作为叶用银杏家系苗期选择的重要指标。     

Callose in root apices of European chestnut seedlings: a physiological indicator of aluminum stress

We determined if callose formation in 1-cm-long root apices of European chestnut (Castanea sativa Mill.) seedlings is affected by naturally occurring high concentrations of aluminum (Al) under laboratory conditions and by low base saturation (BS) of soils under forest field conditions. Under controlled conditions in the laboratory, seedlings were treated with simulated soil solutions in the presence or absence (control) of Al. One day after exposing seedlings to a simulated soil solution containing 168 microM Al, callose formation in the root apices had increased significantly. After 7 days, callose concentration in root apices was significantly correlated with the concentration of free Al3+ ions recovered in the simulated soil solution and with the concentration of Al in fine roots. At four field sites in southern Switzerland, seedlings were grown for five months in either A-horizon soil with a BS above 17% or in a B-horizon soil with a BS below 5%. Callose concentrations were significantly higher in root apices in the B horizon than in the A horizon. Callose concentrations in root apices were negatively correlated with Ca/Al molar ratio in fine roots. We conclude that callose in the root apices of European chestnut could be a useful physiological parameter for assessing Al toxicity under both laboratory and field conditions.     

Farm woodlots in rural Rwanda: purposes and determinants

The development of farm woodlots as an alternative source of livelihood for smallholder farmers in diverse biophysical and socio-economic conditions is a challenging issue in developing countries, such as Rwanda, where the majority of the population relies on subsistence farming. There is a need to understand why and when farmers decide to grow trees and woodlots on their farms. The objective of this study was to analyse the determinants and the purposes that enhance the propensity to grow woodlots in low, medium and high altitude regions of Rwanda. Necessary information for this study came from a survey of 480 households across these regions. The results showed regional variations in the determinants of woodlot farming, demonstrating the importance of not extrapolating the results between regions. Pooled data across regions indicated that age of the householder, number of salaried household members, farm size, travel distance to fuelwood sources and household location in medium forest cover region had positive significant effects on the propensity to grow farm woodlots. In contrast, household location in low forest cover region, ownership of livestock and monthly frequency of purchasing fuelwood were inversely related to the presence of farm woodlots. Many households planted eucalyptus woodlots for economic reasons, not for environmental purposes. Livestock and crop production were more attractive to rural households than woodlot farming. The findings of the study can be used by policymakers and extension services in order to promote sustainable land use practices by focusing on the challenges of competing land uses, farm size, unemployment, dependence on forests for fuelwood supply and subsistence farming.     

The Roles of Climate Variability and Habitat Heterogeneity in Structuring a Forested System: An Integrated Accumulation Function of Species Richness

As forested systems are impacted by both natural and anthropogenic factors such as climate change, the biodiversity supported by those forests is likely to change. Quantifying that change, however, remains a difficult task due to variations in the sizes and conditions of forested systems. Species accumulation curves are a commonly used tool to scale estimates of species richness and provide an avenue for comparing biodiversity among habitats through rarefaction. However, we found that the ranked biodiversity among forested systems depends on the sample unit used, and there is a need to integrate landscape heterogeneity in spatially scaleable estimates of biodiversity. Both of these biodiversity assessment issues can be addressed using a new approach we term the Integrated Accumulation Function (IAF), a method based on combining component species accumulation curves. Using this approach on communities of canopy arthropods found in pinyon pine forests in the southwestern United States, we found three major patterns. First, in small stands, trees growing under low environmental stress support the greatest species richness. Second, when stands are large, stands growing under higher environmental stress support greater species richness, and species richness is resilient to change over a broad range of the stress gradient. Third, there are threshold levels of stress at both ends of the stress spectrum beyond which species are rapidly lost. This analysis reveals unexpected patterns and suggests that conservation practices should consider the inclusion of forests growing under suboptimal conditions to maximize the preservation of biodiversity.     

3种竹笋夜蛾生态位及其种间竞争的研究

竹笋夜蛾是竹林笋期最主要的害虫之一,应用昆虫种群生物学理论对早园竹、红竹和淡竹笋上3种夜蛾种群动态及生态位进行了研究.结果表明:淡竹笋夜蛾和笋秀夜蛾在种群数量上明显占优,前者发生高峰期集中于4月底至5月初,约7 d,后者集中于5月中旬,约10 d,二者在发生时间上相互分离;竹笋禾夜蛾发生数量少,危害相对较轻.淡竹笋夜蛾的时间生态位宽度在3种夜蛾中最小,竹笋禾夜蛾和淡竹笋夜蛾的生态位相似比例较高(>0.7),种间竞争系数高达0.907 3,说明二者在利用时间资源上发生重叠,二者存在明显资源竞争,最终导致淡竹笋夜蛾种群密度和数量比例显著高于竹笋禾夜蛾.竹笋禾夜蛾的生态位宽度和笋秀夜蛾接近.3种竹笋夜蛾共存同一株竹笋的情况不存在,即使是2种夜蛾共存于同一竹笋的几率也很低,平均值也仅为0.97%.     

20个茶花品种遗传关系的ISSR分析

采用ISSR分子标记技术对茶花品种群中有代表性的20个国内外茶花品种进行了品种间遗传关系的分析.从60对随机扩增引物中筛选出了21对扩增带型清晰及重复性好的引物序列,共扩增出153条带,其中146条呈现多态性,多态性条带比例为95.4%;Nei's基因多样性指数介于0.40～0.48,Shannon信息指数在0.57～0.67,基因分化系数介于0.5～0.7,基因流值介于0.2～0.5,遗传相似系数介于0.50～0.74,平均为0.63.参试的20个茶花栽培品种间遗传差异相对比较窄;结合花型形态学特征与UPGMA聚类分析结果,可将20个茶花品种分为2个大类群.此外,结果显示:ISSR分子标记适用于分析山茶品种间遗传多样性和亲缘关系.     

杂种落叶松家系苗期高生长变异规律的研究

对林口县青山林场落叶松杂种苗与各优良种源苗(2年生)进行变异分析的结果表明,各种源间存在丰富变异,变异系数在26.8%～46.9%之间,平均为32.8%;各种源间苗高生长量差异极显著,青山种源杂种苗高生长最快,为49.21cm,小北湖优良种源苗高生长最慢,为22.6cm,青山种源高生长比小北湖种源高生长快117.7%;23个落叶松各家系间苗高差异极显著,生长最快的黑龙江青山Q6号家系(58.04cm)比生长最慢的小北湖家系(22.6cm)快156.8%.各家系内苗高存在丰富变异,变异系数在17.5%～46.9%之间,平均为26.3%.种源内家系间苗高差异极显著.