Higher resistance of the offspring of Scots pine trees resulting from natural regeneration in old foci of Heterobasidion annosum root rot

Abstract

Heterobasidion annosum (Fr.) Bref. is a fungal pathogen causing annosum root rot – one of the most economically important diseases in coniferous stands. The major aim of this study was to compare the resistance of the offspring of Scots pine trees (Pinus sylvestris L.) from seed orchards and the offspring of trees that were naturally reproduced in old foci of the disease. In experiments conducted in vitro, we used 960 seedlings which were grown from seeds collected from 60 trees in 6 old foci of the disease and 640 seedlings grown from seeds collected in 4 seed orchards. The offspring of trees from seed orchards after inoculation with H. annosum had nearly twofold higher mortality rate than the seedlings developed from the seeds collected in old foci of the disease. This suggests that the offspring of self-sown trees in old foci of the disease has a greater, genetically conditioned resistance to annosum root rot.     

Estimating risks for spruce bark beetle (Ips typographus (L.)) damage using pheromone‐baited traps and trees

The risk for damage associated with spruce bark beetle attacks on living trees was estimated in 12 forest districts in the Nordic countries during three years. Pheromone‐baited traps and trees were used. Five groups of three traps were deployed annually on fresh spruce clear‐fellings in each district. The mean catches within districts and years ranged from 950 to 46000 beetles per trap group. The standard error averaged 15 % of the mean catch. One tree was baited annually at each of five other sites in each district. The mean number of trees colonized by Ips typographus in each district and year ranged from 0 to 5 per site. The standard error was high, averaging 44% of the mean. Inventories of tree mortality within the districts yielded values ranging from 0 to 150 killed trees per km of spruce forest edge. There was a strong linear correlation between mean catches in traps and log‐transformed tree mortality (r=0.82). The correlation between colonization success at tree‐baiting sites and tree mortality was weaker (r=0.59), owing to one deviant observation. The results indicate that pheromone traps and baited trees may be used to assess the risk for damage caused by Ips typographus.     

闽楠人工林与天然林生长特点比较

选择福建省南平市延平区29年生的闽楠人工林和明溪县35年生的闽楠天然林平均木,采用树干解析法,进行闽楠人工林与天然林的生长差异比较。结果表明:29年生的闽楠人工林,其平均树高、胸径、材积生长量明显大于35年生的天然林,人工林的树高年平均生长量最大值出现在15年生,连年生长量最大值出现在10年生左右,连年生长量和年平均生长量在16～17 a左右相交;人工林、天然林胸径年平均生长量最大值同时出现在15年生;人工林材积连年生长量在15年生时达最高峰,天然林则在30年生时达最高峰,人工林与天然林材积连年生长量最大差值出现在15年生,随后差值缩小,到29年生时天然林的材积连年生长量反而略大于人工林,表明天然林具有较大的生长潜力。闽楠人工林经营应处理好立地和密度的关系,才能持续速生并取得良好效果。     

北京紫竹院公园早园竹叶螨及蚜虫综合治理技术研究

对北京市紫竹院公园早园竹林叶螨及蚜虫的综合防治技术进行了研究。结果显示,竹林密度和通风条件影响害虫的发生情况;施用低毒高效的生物药剂可有效控制害虫的蔓延;保护利用天敌可有效控制害虫的发生;竹林害虫的防治宜采取化学防治和生物防治相结合的综合防治措施。     

别墅建筑的几种空调设计方案

介绍了可用于别墅建筑的冷风式成套热泵空调机组系统、风冷热泵冷水机组系统、风冷式热泵分体空调系统等供暖制冷系统的方案，并指出应根据不同的能源和气候条件，选择合适的系统，以满足用户和房地产商的利益要求。     

西藏天然林资源保护工程现状及发展对策研究

1　天然林保护工程实施以来取得了明显的阶段性成果西藏是我国重要国有天然林区之一 ,现有有林地面积 75 1万hm2 ,约占国有林区天然林面积的 2 7 8% ,活立木蓄积量为 2 0 84亿m3 ,约占国有林区天然林蓄积量的 72 %。昌都地区的江达、贡觉、芒康 3县是我国长江流域的重要区域 ,     

珙桐种子散布、萌发及其种群龄级分配的关系研究

珙桐 (Davidiainvolucrata)为我国单属种的特有植物。珙桐起源古老 ,系第三纪古热带植物区系的孑遗种 ,在植物系统发育和地史变迁研究上有很高的学术地位 ,被列入国家一级保护珍稀濒危植物。此外 ,珙桐开花时其头状花序基部有 2枚白色的大苞片 ,随风飘动 ,如白鸽展翅 ,有“中国鸽子树”之称 ,有极高的观赏价值 ,是重要的园林绿化树种 (贺金生等 ,1 995 ;傅立国等 ,1 992 )。过去对珙桐的研究涉及到许多方面 ,如它的分类地位 (Li,1 95 4)、引种繁殖 (唐晓军 ,2 0 0 2 ;沈作奎等 ,1 998;张家勋等 ,1 995 )、解剖特征 (孙彬等 ,1 993 )、生殖…     

社区自然资源管理的五个基本要素

本文介绍了社区自然资源管理的5个基本要素:①当地人是自然资源管理的主体,充分赋权于当地人,包括项目决策权、实施参与权、知情监督权、管理维护权、监测评估权;②尊重乡土知识、乡土人才,重视能力建设;③关注农村妇女和弱势群体的参与和能力建设,倡导性别平等及公平的发展观;④在当地村规民约基础上建立社区管理制度和管理组织,促进当地村民的自我管理、自我发展;⑤有偿使用、有偿管理、有偿服务,增强当地村民对项目的拥有感,实现项目的可持续性.     

木工带锯条系统固有频率声学测量

采用声学测量法测试木工带锯条系统的固有频率,对带锯条研发与检测技术具有一定的应用价值,并为各类木工机械与刀具系统的固有频率测试提供借鉴的方法.     

天然膨润土吸附Cu2+的动力学、等温线及热力学研究

文章讨论了不同影响因素如接触时间、振荡速度、膨润土用量、初始离子浓度、初始pH、温度等对膨润土吸附性能的影响,研究了Cu2+在天然膨润土上吸附的动力学、等温线和热力学理论。动力学研究数据表明,吸附满足准二级动力学模型,吸附初始阶段受界面扩散控制,45 min后受粒子内扩散控制;吸附满足Freundlich等温线模型;吸附是一个自发的、吸热的过程,而且反应不可逆。