不同海拔高度引种秃杉试验初报

在福建省德化葛坑国有林场不同海拔高度的山地引种栽培秃杉,并与杉木、柳杉、福建柏进行造林对比试验。结果表明:18年生秃杉在海拔550 m8、00 m9、80 m与1 650 m的生长差异达显著水平;在不同海拔高度,秃杉与杉木、柳杉、福建柏的生长差异显著,秃杉的单株材积增幅达19.3%~49.3%。说明秃杉宜在海拔500~1 000 m引种,其生长量最大,效益最好,是福建省中高海拔山区杉木采伐迹地的优良更新树种。     

浅谈科技论文中试验和实验的区别与联系

探讨了"试验"和"实验"两词含义的区别与联系,对"试验"和"实验"的异同点进行概念分析,提出使用的建议。     

浙江毛竹林分非空间结构特征及其动态变化

利用2004与2009年浙江省两期森林连续清查毛竹样地数据,应用因子分析、聚类分析、相关分析、多元方差分析及核密度估计方法,采用7个指标(样地生物量,样地株数,林分平均胸径,1,2,3和≥4度竹所占比例)描述毛竹林分非空间结构特征。结果表明:毛竹林分非空间结构特征的主导因素依次为年龄结构因子、样地生物量因子、林分平均胸径因子;浙江现有毛竹林老龄化问题较突出,林分中各龄级所占比极不合理,现有经营措施存在较大缺陷,从而使林分生产力衰退;样地株数较少时,林分平均胸径与样地株数几乎没有相关性,但随着样地毛竹株数的增加,表现出一定的负指数关系;影响毛竹林分生物量的主要因素依次是样地株数与林分平均胸径;7个指标中除3度竹所占比例没有显著差异外,其他指标都存在显著差异,使得毛竹林分非空间结构(由7个指标构成)在2004年与2009年存在显著性差异;平均胸径小于8.7 cm的林分随着毛竹的生长所占比重在减少,而平均胸径大于8.7 cm的林分在增加,这也说明2009年林分平均胸径比2004年显著增大,样地株数和林分生物量与林分平均胸径有类似的趋势。研究结果对毛竹林的可持续经营与固碳功能的提高有一定的参考价值。     

不同杨树品种冠径比的差异性分析

对32个杨树品种冠幅与胸径比例关系的差异性进行比较,结果表明:不同杨树品种冠径比存在极显著差异,107杨、鲁山杨、W46杨、95杨、895杨等5个品种具有生长快和冠径比小的优点。冠径比在品种选择和密度确定等方面具有一定参考价值。     

Evaluating the Impacts of Forest Management Policies and Community-Level Institutions in the Buffer Zone of Chitwan National Park,Nepal

A Master Plan for Nepal’s Forestry Sector (MPFS), enacted in 1989, and subsequent legislation laid the foundation for modern community-based forest management in Nepal. In 2014, the MPFS reached the end of its 25-yr lifespan, after successfully ushering in significant institutional changes that fundamentally transformed the management of Nepal’s forests, mostly through devolving management and benefits from the national level to local communities. Here, we use the 25-yr anniversary of the MPFS to explore forest cover trends in the buffer zone surrounding Chitwan National Park (CNP). Landsat imagery was used for the years 1989, 2005, and 2013 to compute a normalized difference vegetation index (NDVI) to analyze trends in forest cover for 36 buffer zone village development committees (VDCs). The analysis, covering approximately 1,267 km², found that since the MPFS was enacted, there was first a continued decrease in forest cover, followed by a significant recovery. These data offer insight into the success of modern community-based forest management policies and supporting institutions, and provide a model for other efforts to conserve forest resources in Nepal and elsewhere.     

利用试差法确定林业抽样调查中的样本容量

本文针对正态总体的情形,讨论了如何利用试差法确定样本容量,即利用 n=1+s~2/(Δ (?)~2)·t~2_(n-1)(a) 式反复迭代,直到求出的n值差异很小为止,这时的n值即为所求的样本容量。文中并给出了试差法在林业中的应用实例。     

笼养孟加拉成年虎与亚成虎白昼行为的差异研究

2005年12月至2006年8月,采用瞬时扫描取样法和全事件取样法,对云南野生动物园内7只孟加拉虎行为进行了初步观察。结果表明,在观察期内,笼养孟加拉虎白昼行为时间分配上成年虎与亚成年虎之间存在一定差异,即成年虎的睡眠多于亚成年虎的睡眠;成年虎的卧息、走动、摄食和其他行为少于亚成年虎的卧息、走动、摄食和其他行为。活动节律上有一定的相似性,但也存在差异,不同年龄之间卧息和走动出现两个高峰,睡眠出现一个高峰,但亚成年虎的睡眠较为集中。     

Site index models for Calabrian pine in the central Mediterranean region of Turkey

Stem analysis data of 432 trees were obtained from even-aged, pure natural stands of Calabrian pine in the central Mediterranean Region of Turkey. Eight dynamic site equations derived with the Generalized Algebraic Difference Approach (GADA) were compared, based on autoregressive analysis and a thorough evaluation of the goodness of fit. We used generalized nonlinear least squares methods for model fitting. The adjusted coefficients of determination (0.9825–0.9842), root-mean-square errors (0.8004–0.8435 m), and Akaike’s information criterion differences (0–145) indicated a good fit of the eight site index equations. The Hossfeld equation (M3) provided the best result. The Durbin-Watson test statistic did not reveal an autocorrelation issue while the Hossfeld equation provided a satisfactory solution to the serial correlation problem in stem analysis data as time series using autoregressive modeling. This study presents new site index models for Calabrian pine forests in the central Mediterranean region of Turkey where it is the most important commercial tree species. The site index equation, based on the Hossfeld model is recommended for height growth prediction and site classification of Calabrian pine stands in the central Mediterranean region of Turkey, providing a new basis for growth prediction and yield estimation in these important forest ecosystems.     

Anti-diabetic effects of emodin involved in the activation of PPARγ on high-fat diet-fed and low dose of streptozotocin-induced diabetic mice

Rheum palmatum Linn has been widely applied in the clinical treatment of diabetes mellitus. It has been found that emodin as the major bioactive component of R. palmatum L exhibits the competency to activate peroxisomal proliferator-activated receptor-γ (PPARγ) in vitro. So the aim of this study was to evaluate the anti-diabetic effects of emodin through the activation of PPARγ on high-fat diet-fed and low dose of streptozotocin (STZ)-induced diabetic mice. The diabetic mice were intraperitoneally injected with emodin for three weeks. No changes of food consumption and the body weight in emodin-treated mice were monitored daily during the entire experiment. At the end of experiment, the levels of blood glucose, triglyceride and total cholesterol in serum were significantly decreased after emodin treatment. However, serum high-density lipoprotein cholesterol (HDLc) concentration was significantly elevated. The glucose tolerance and insulin sensitivity in emodin-treated group were significantly improved. Furthermore, the results of quantitative RT-PCR analysis showed that emodin significantly elevated the mRNA expression level of PPARγ and regulated the mRNA expressions of LPL, FAT/CD36, resistin and FABPs (ap2) in liver and adipocyte tissues. No effects on the mRNA expressions of PPARα and PPARα-target genes were observed. Taken together, the results suggested that the activation of PPARγ and the modulation of metabolism-related genes were likely involved in the anti-diabetic effects of emodin.