天然更新伯乐树的生长过程初步分析

解析1株天然林中148年生伯乐树倒木树干，表明其树高连年生长量在65年生时达到最大值，和树高年平均生长量曲线相交于80年生时；胸径连年生长量在70年生时达到最大值，与胸径年平均生长量相交于95-100年生时；而材积连年生长量的最大值出现在80年生时，与材积年平均生长量于135-140年间相交，此时可以认为是伯乐树的材积数量成熟年龄。     

PTDCA模式在黄土丘陵区防护林建设中的应用

笔者通过黄土丘陵区防护林综合配套技术构建的实践与探索,结合林业工程的生态公益性出发,以参与式PDCA项目周期管理方法为基础,创造性地引入培训(Train)这一环节,提出了增能扩效PTDCA项目周期管理模式。具体阐述了PTDCA的涵义,从制定计划、培训、项目实施、监测评估和完善改进5个方面介绍了PTDCA在防护林建设中的应用过程,指出了项目实施具有提高森林覆盖率、提高造林成活率与保存率、增加林木生长量和加强培训效果4个方面的成效,最后对PTDCA项目周期管理模式今后的发展进行了展望。     

用EL-5100计算器现地控制抚育强度

笔者采用EL-5100计算器进行抚育强度的计算,并对设计抚育强度和计算抚育强度进行了比较。通过建立回归方程,进行方差分析和几何解析,证实该计算方法的实用性和可行性。结果表明,该方法能够使外业调查在1 min~2 min的时间内现地控制抚育强度,为天然林保护工程快速确定抚育强度提供参考。     

海林市地方国有林区纳入国家天然林保护工程的思考

介绍了海林市地方国有林区的基本情况,分析了国有林场面临的困难和存在的问题,阐述了地方国有林区纳入国家天然林保护工程的重要意义,并提出了相关建议。     

移动通信基站在森林防火工作中的应用

移动通信基站基于卫星系统和通信系统的相关技术已相对成熟,在森林防火工作中已逐渐推广应用。本文根据工程实例,简要阐述了移动通信基站在森林防火工程项目中的应用。     

基于森林资源现状的加格达奇林业局林业发展对策探讨

在加格达奇林业局森林资源现状基础上,分析了该林业局森林资源的特点,探索了提高加格达奇林业局森林资源质量,发挥森林资源的多种功能的思路,并提出加格达奇林业局的森林经营方案和发展对策。     

滇西北退耕还林后续政策分析及发展对策

滇西北是云南省最为贫困的少数民族聚集地区之一,实行退耕还林政策10多年来取得了巨大的成效,随着退耕还林政策补助陆续到期,部分退耕农户生计将出现困难。对退耕还林后续政策进行分析,认为退耕还林补偿标准与现有物价水平不符,套种的规定过于保守,针对政策上的不足与实施过程中存在的作业设计不够规范、监管不力、档案管理不够规范等问题提出相关对策和建议。     

High clay content accelerates the decomposition of fresh organic matter in artificial soils

Clay is generally considered an important stabiliser that reduces the rate of decomposition of organic matter (OM) in soils. However, several recent studies have shown trends contradicting this widely held view, emphasising our poor understanding of the mechanisms underlying the clay effects on OM decomposition. Here, an incubation experiment was conducted using artificial soils differing in clay content (0, 5, and 50%) at different temperatures (5, 15, and 25 °C) to determine the effects of clay content, temperature and their interaction on fresh OM decomposition. CO₂ efflux was measured throughout the experiment. Phospholipid fatty acids (PLFAs), enzyme activities, microbial biomass carbon (MBC), and dissolved organic carbon (DOC) were also measured at the end of the pre-incubation and incubation periods in order to follow changes in microbial community structure, functioning, and substrate availability. The results showed that higher clay contents promoted OM decomposition probably by increasing substrate availability and by sustaining a greater microbial biomass, albeit with a different community structure and with higher activities of most of the extracellular enzymes assayed. Higher clay content induced increases in the PLFA contents of all bacterial functional groups relative to fungal PLFA content. However, clay content did not change the temperature sensitivity (Q₁₀) of OM decomposition. The higher substrate availability in the high clay artificial soils sustained more soil microbial biomass, resulting in a different community structure and different functioning. The higher microbial biomass, as well as the changed community structure and functions, accelerated OM decomposition. From these observations, an alternative pathway to understanding the effects of clay on OM decomposition is proposed, in which clay may not only accelerate the decomposition of organic materials in soils but also facilitate the SOM accumulation as microbial products in the long term. Our results highlight the importance of clay content as a control over OM decomposition and greater attention is required to elucidate the underlying mechanisms.     

江苏徐州市果树经济林的碳储量估算

采用生物量法和重铬酸钾-硫酸氧化法测定全碳含量,对徐州市果树经济林的碳贮量、分布格局进行初步研究。徐州市果树经济林碳储量为39.21×104 t,其中,银杏18.45×104 t、梨3.82×104 t、苹果16.63×104 t、桃2.67×104 t。碳密度为8.7 t/hm2,并分析其空间分布特点。     

大兴安岭北部林区森林防火基础设施建设成效及对策

大兴安岭北部林区森林防火基础设施建设项目是建国后国家一次性用于国有林区森林防火投资最大的基础设施建设工程。介绍了该项目建设的基本情况,总结了主要建设成效,分析了存在问题,提出了相关对策建议。