Planted conifer seedling growth under two soil thermal regimes in high-elevation forest openings in interior British Columbia

A field trial was conducted investigating the single season growth response of 1+0 313 PSB Engelmann spruce (Picea engelmannii Parry ex Engelm.) and lodgepole pine (Pinus contorta Dougl. ex Loud.) seedlings planted into two different soil thermal regimes at three high-elevation locations spanning 200 km in the Engelmann Spruce-Subalpine Fir (ESSF) biogeoclimatic zone in the Cariboo Mountains of central British Columbia. Temperature treatments represented the extremes of soil temperature commonly found in high-elevation clear-cuts. A warm soil treatment (clear day, mid-afternoon soil temperature in mid-summer of 18 to 25 °C at –10 cm) consisting of a bare mineral soil hummock (average dimensions of 100 cm × 100 cm × 40 cm) was contrasted with a cool soil treatment (clear day, mid-afternoon soil temperature in mid-summer of 10 to 13 °C at –10 cm) comprised of organic forest floor overlying mineral soil. By the end of the growing season, seedlings of both species planted into the warm treatment generally exhibited greater root, stem, foliage, and total seedling biomass than cool treatment seedlings. Measurements of root growth at 30, 60, and 90 days after planting showed that total root number and total root length were consistently greater for warm treatment seedlings than for cool treatment seedlings. Root growth was greater from the bottom rather than from the side of the root plug for all seedlings. These results suggest that the effect of low soil temperatures on outplanted styroblock conifer seedlings is pronounced and may be limiting growth performance in high-elevation plantations in British Columbia. We recommend silvicultural treatments that secure natural regeneration, ensure that warmer microsites are always planted, and utilize seedling stocktypes able to make rapid lateral root growth into warmer surface organic horizons.     

The implications of various silvicultural funding arrangements for privately managed public forest land in Canada

When devising policies for financing private silvicultural operations on public forest land, government agencies should consider carefully the benefits and costs of alternative arrangements and how they arc likely to affect tenure holders' behavior. Three general methods of achieving silvicultural objectives arc discussed — the creation of incentives for private voluntary expenditures, reimbursement by governments of expenditures on approved or required silvicultural operations, and required silvicultural operations at the tenure holder's expense.Private firms will only invest voluntarily in silviculture on public lands if they have adequate security of tenure and hold sufficient equity in the timber values resulting from their activities. If firms' silvicultural costs arc reimbursed, their behavior will depend on the extent of reimbursement and whether they have a financial interest in the outcomes of their reimbursed activities. Generally, reimbursement of expenditures must be supported by minimum performance standards and costly monitoring and enforcement procedures. If silvicultural operations are required at the tenure holder's expense, firms will only undertake silviculture to avoid penalties and have a strong incentive to achieve required standards at minimum cost. More stringent monitoring and enforcement procedures may be necessary than if costs arc reimbursed.The impact of policy alternatives is illustrated by means of a survey of silvicultural expenditures on two forest tenure types in British Columbia.     

集水区内森林生态系统的养分分析

在湖南省会同县森林生态系统定位站小集水区杉木人工林生态系统中,对植被、土壤和水分的营养元素(N,P,K,ca,Mg)进行分析测定,结果表明:系统中植被的养分含量,因器官类型、生长季节和年龄的不同而不相同;土壤养分含量,因立地条件类型的差别而有明显的差异;水分中的营养元素,随天气状况、降水性质和时间的变化而发生变化,并阐述了进行此类研究的方法及应予引起注意的问题。可供进行类似研究时参考。     

国有林场树种结构调整及稳定性分析--以湖南省国有武冈林场为例

运用目标规划模型对湖南省国有武冈林场的森林树种结构进行优化,得到其理想的树种结构,然后计算出理想树种结构的信息熵和信息熵相对值,用于评价该场的树种结构稳定性.评价结果表明:该场1990～1999年的树种结构信息熵变化不大,稍有增势,比理想的树种结构信息熵偏小,这说明该场现有的树种结构处于过于有序状态,即,人工干扰过大,会损失某些利用功能.该评价结果可为其森林经营结构的调整提拱科学的参考依据.     

我国与森林植被和水资源有关的环境问题及研究趋势

我国存在水资源数量不足和时空分布不均、水质下降、水环境恶化、旱涝灾害频繁、水土流失严重等生态环境问题;增加森林植被是解决水资源水环境问题的重要途径,我国正在进行空前大规模的林业生态环境建设,非常需要生态水文学的科学理论和技术支持。已有的森林水文学研究结果存在内容完整性和系统性差、尺度偏小、过程单一、缺乏对森林植被的水分稳定性认识、不能预测森林植被的区域水文影响等不足,还没有形成能有效指导调控林水关系和进行流域水资源管理的成熟理论和技术;未来需要加强的研究重点,包括鼓励跨部门和跨学科的交叉、森林植被的耗水特性和水分稳定性、森林水文作用的形成机理及其尺度效应和尺度转换、森林植被对区域水文影响的预测和评价、森林对水质的影响及作为重要水源保护区和流域水资源管理途径的森林植被建设技术等。     

植物近等基因系培育及在林木遗传改良上的应用探讨

近等基因系是分子遗传图谱构建、数量性状基因定位及分子标记辅助育种的重要基础。近等基因系选育主要有连续多次回交选育法、从突变体中分离获得、结合分子标记技术检测连续回交选育法、杂交高世代群体材料中分离选育等方法。本文介绍了主要农作物近等基因系构建及应用的研究进展,并结合林木植物的特点,提出了选择生长周期较短的木本植物柳树为材料,构建近等基因系,在此基础上形成林木遗传学研究模式树种的观点。     

我国实施森林分类经营中存在的问题

森林分类经营是当前林业界的热点问题之一，国家林业局已将其作为总体推进林业发展的龙头工作和全面推进林业政策的“牛鼻子”工程，但在实施森林分类经营中还存在着一些问题。诸如：林业观念问题、两类林的划分问题、公益林生态效益补偿机制等问题，本文就以上这些问题予以初步探讨。     

Problems and relevant strategies on natural forest protection in Changbai Mountain forest area

Changbai Mountain forest area is not only is a national timber base but also a green ecological defense for Songliao Plain of NE China. The Natural Forest Protection Project of this area has an important bearing on the social and economic sustainable development of Jilin Province or even the whole forest area in NE China. This paper summarized general conditions of natural forest in Changbai Mountain state-owned forest area and put forward six problems need to be urgently solved and five strategic suggestions on natural forest protection and sustainable management.     

森林生态效益计量评价的理论方法概述

森林生态效益计量评价是对一定时期森林所提供的生态效益大小的计量。文章论述了森林生态效益计量评价的理论和方法。为了使评价结果更真实客观,从而能为社会承认和接受,提出应从森林生态效益划分标准问题、综合效益定量问题、林龄动态分析等方面进行深入的研究。