江苏省森林采伐限额的编制

根据《森林法》和《森林法实施细则》规定,对森林实行限额采伐,年森林采伐限额每5年调整1次。为了做好1991～1995年森林采伐限额的编制工作,根据林业部的要求,结合本省森林资源现状,将森林限额采伐编制方法和要求叙述如下: 1 采伐限额的范围 除社员房前屋后小四旁立木蓄积和自然保护区林木蓄积不在采伐限额范围内,其他林木蓄积(包括用材林、防护林、特用林、疏林、散生木、大四旁林木蓄积)都要编制采伐限额。     

“十二五”期间年森林采伐限额编制方法与技术

森林采伐是调整森林结构、改善森林质量、增加森林总量、提高森林整体功能的关键措施。实行森林限额采伐管理是《森林法》确立的一项重要法律制度。介绍了"十二五"期间年森林采伐限额编制的原则、方法与技术,以期为森林资源采伐管理工作提供借鉴。     

辽宁省“十二五”期间年森林采伐限额编制方法与技术

森林采伐是调整森林结构、改善森林质量、增加森林总量、提高森林整体功能的关键措施。本文介绍了辽宁省“十二五”期间年森林采伐限额编制的原则、范围、单位、方法与技术，以期为森林资源采伐管理工作提供借鉴。     

森林采伐限额编制中的分类经营思想

森林采伐限额制度是我国林业发展史上的一项重大改革,采伐限额管理是森林资源管理的关键和核心内容之一,科学编制采伐限额是严格执行采伐限额制度的基础和前提。本文对采伐限额的概念、内涵及其与年度木材生产计划、采伐许可证的关系进行了阐述;通过对限额编制历史的回顾,清晰地呈现了限额编制和管理的发展变化趋势;分析和总结了贯穿于采伐限额编制工作中的森林分类经营思想;简要介绍了未来5年限额的审编原则和特点。     

“九五”限额编制回顾与“十五”限额编制意见

论述了“九五”期间年森林采伐限额编制过程和特点,提出“十五”期间年森林采伐限额编制的意见和建议。     

论森林采伐限额制度的法律意义

森林采伐限额制度是国家控制森林资源过量消耗 ,实现林业可持续发展的重要举措。森林采伐限额制度已纳入我国法制化轨道。依法执行森林采伐限额制度是依法治林的重要内容。一、森林采伐限额的法律依据为了控制森林资源的过量消耗 ,实现森林资源的永续利用 ,１９９８年１月颁布实施的《森林法》明确规定了采伐森林必须实行森林采伐限额制度 ,同时规定了森林采伐限额编制的原则和程序等。森林采伐限额制度正式列入我国的《森林法》 ,以法律的形式在我国开始实施。１９９８年４月我国公布了重新修订的《中华人民共和国森林法》 ,修订后的《森林…     

曲靖市“十二五”期间年森林采伐限额编制方法与成果分析

指出了森林采伐限额是《森林法》确定的一项法律制度,是控制森林资源消耗的有效手段。以曲靖市“十二五”期间年度森林采伐限额编制为例,介绍了采伐限额编制的原则、方法及特点,并对编限结果进行了分析,以期为即将编制的“十三五”期间年森林采伐限额编制提供参考。     

辽宁省年森林采伐限额编制执行情况浅析

辽宁省"十四五"采伐限额编制工作已全面完成,"十四五"期间能否按要求、高标准、高质量执行年森林采伐限额,切实发挥森林采伐限额制度的作用,对森林资源保护发展具有十分重要的意义.该文通过深入分析辽宁省"十四五"采伐限额编制情况,结合"十三五"采伐限额执行情况,提出了在"十四五"采伐限额编制、"十三五"采伐限额执行以及目前采...     

森林采伐限额理论与实践若干技术问题的研究

通过系统总结我国10年来森林采伐限额理论和实践的经验,阐述了森林采伐限额与森林经理学的关系,并就采伐限额编制、调整和检查监督等若干关键技术问题以及福建省的实践展开探讨、研究,旨在抛砖引玉,共商实行森林采伐限额制度之大策。     

以科学发展观指导“十一五”期间年森林采伐限额编制工作

在充分认识实行森林采伐限额制度重要意义的基础上,论述了树立和落实科学发展观就是要在"十一五"期间年森林采伐限额编制中,坚持生态优先,注重森林资源的经济、社会、环境三大效益的协调发挥,立足于森林资源的实际,根据经济规律、林学规律和社会发展的客观规律,科学、合理地编制森林采伐限额。阐明了"十一五"期间年森林采伐限额编制在指导思想、编制原则、编制范围、编制方法等方面的新进展、新变化、新特点及其对具体编限工作的指导意义。分析了在涉及采伐限额数量、采伐类型和可采资源、出材率、保护区禁伐等具体问题时应如何正确理解、准确把握《"十一五"期间年森林采伐限额编制方案》中的有关要求,并详细讲解了具体操作方法。全文对正确理解、准确把握、认真落实《关于编制"十一五"期间年森林采伐限额工作的通知》精神,切实做好"十一五"期间年森林采伐限额编制工作具有参考价值。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.