Pattern of Kirtland's warbler occurrence in relation to the landscape structure of its summer habitat in northern Lower Michigan

Studies of the endangered Kirtland's warbler in relation to landscape ecosystems were conducted from 1986–1988 on a large wildfire-burn surrounding Mack Lake in southeastern Oscoda County, Michigan. A landscape ecosystem approach was used to distinguish low- and high-elevation segments of the landscape, as well as 11 local ecosystem types. The ecosystems were distinguished by physiography, microclimate, soil, and vegetation. The early occurrence of the warblers was strongly related to landscape structure, i.e., to the broad low- and high-elevation areas and the local ecosystem types within them. Territories of male warblers were observed in 5 of the 11 ecosystems. The five ecosystem types where warblers were observed were characterized by (1) a physiography of level or rolling terrain; (2) soil series of Grayling, Graycalm, Montcalm, or Rubicon; (3) uplands with relatively warm temperature during the breeding season; (4) vegetation dominated by low sweet blueberry, bearberry, wintergreen, northern pin oak, blue stem grasses, and hair cap moss; and (5) canopy of relatively tall, dense, and patchy jack pine and oak. Landscape structure appears to be an important factor affecting the occurrence of the warbler in its summer habitat in northern Lower Michigan.     

经济林生产机械装备用户需求分析

基于浙江省8个城市的20个样本数据,对用户经济林生产机械装备种类、普及率、使用率、满意度、生产效率、生产风险以及机械装备需求等因素进行分析。结果表明,经济林机械装备有14种,用户对多种机械均有使用,在涉及林地面积上使用率较高,在涉及林业生产活动工序上使用率较低;用户对价格满意度一般,对生产效率和生产风险较满意,认为在使用机械设备过程中个人技术较重要;用户对高性能机械装备需要较高,认为加强社会化服务、规模化经营以及政府组织发挥作用是解决经济林生产装备机械化的途径。藉此,提出提升机械设备使用率,加大队伍培训力度,创新林业机械发展等策略。     

Factors influencing male mating success in bur oak,Quercus macrocarpa

Pollen donors of acorns and saplings in a stand of bur oak were identified by paternity exclusion using microsatellite genotype analysis. Here we examine the influence of several factors likely to affect reproductive success of males with wind-dispersed pollen, including distance of pollen donor from maternal tree, genetic relatedness of pollen donor to maternal tree, direction of pollen donor relative to maternal tree, and size of pollen donor (crown volume and trunk diameter). Surprisingly, none of these factors were strongly correlated with fertilization success, although weak but significant correlations with crown volume and distance were found. The slight influence of distance is actually overestimated here, because our analysis necessarily excluded a large proportion of pollinations that were effected by trees outside the stand. The pollen donors outside the stand were not identified, but were more than 150 meters away. Pollination patterns in this stand of bur oak are quite complicated. Seed parents were fertilized by multiple pollen donors within the stand from all directions and as far as 200 m away. These results caution against the use of models of pollination that are based on simple distance or directional parameters because they will not adequately predict gene flow or male reproductive success. Our results further emphasize the importance of genetically identifying successful pollen donors rather than relying on patterns of physical movement of pollen.     

美国城市林业概述

美国城市林业是在高度城市化与城市生态危机的困境中发展起来的,因此,美国城市及其城乡结合部的森林建设与保护一开始就受到美国政府及公众的广泛重视。文中回顾了美国城市林业的起源与发展历程;概述了美国城市林业的学科与法律地位、美国城市林业教育、市民与城市林业的关系,讨论了美国城市林业成功的奥秘及其对我国城市林业建设的启示。     

森林碳汇与区域环境保护

笔者以恩施州为例,运用生物量清单法估算森林碳汇量,运用数学模型估算CO2年排放量。计算出2015年恩施州森林碳汇量100.80万t,CO2年排放量237.61万t,净排放量136.41万t。得出按目前的经济发展速度和恩施州森林年增长量,在2015年CO2不会成为恩施州经济发展的制约因素。但从环境保护这方面出发,同时考虑发展以碳汇为目的的林业经济,恩施州应该加大对森林的管理力度,实行增汇减排措施,并对恩施州森林碳汇发展方向提出相关建议与措施。     

论天然林保护工程中森林工程学科的发展

本文论述了天然林保护工程中森林工程学科的任务。学科发展追求的目的,从学术研究角度探讨了众林工程学科将要遇到的新机遇和新课题。     

管涔林区在天保工程建设中存在的问题及对策

以管涔山森林经营局为对象,分析了在天保工程建设过程中存在的问题,提出了解决问题的对策和建议。     

姥山马尾松1代种子园良种选育

经过１０多年努力，姥山马尾松１代无性系种子园建成投产，经造林测定，６年生子代林的树高、胸径、村积生长量分别比对照提高１５．２％、１８．４％、５６．８％．良种效益显著，并经浙江省林木良种审定委员会审定通过。     

杭州市森检对象和补充森检对象调查

杭州市森林面积９６２６６７ｈｍ＾２，种苗花卉木材及林产品的调运十分频繁，经１９９５￣１９９７年调查，分布国内森检对象８种、外省补充森检对象８种，根据发生、危害情况分类施策，提出控制扑灭等措施。     

沿海沙岸防风固沙木麻黄试验示范林抗御台风分析

湛江市“９６１５”号台风给沿海防护林带来了巨大损失，对国营东海林场木麻黄试验示范林从７个方面进行风害调查分析，结果表明：林木侧根多，而且粗壮，平均胸径大的标准地受破坏轻，抗风能力强；林木平均树高、冠幅和高径比大的标准地受破坏重，抗风能力差。位于临海最前沿的第一试验区受破坏严重；被它保护下的第二至第四试验区受破坏程度逐渐减轻。