转换参数改变对GPS定位值的影响及西安80坐标系转换参数求算

通过对单个转换参数改变对GPS定位值的影响分析,得出水平方向上的两个定位值(x,y)之间为线性关系,再通过对两个转换参数变化的分析得到一组平行的线性曲线。这些特性的存在为求算WGS84到西安80坐标系间的转换参数提供了可能。笔者利用这些特性求算出一套转换参数,并通过外业定位试验说明它们可以满足林业外业工作的需要。     

谈应用CoreldrawX3软件绘制林业工程作业设计图方法

新形势下林业制图既要图面整洁、美观大方,又要高效、简单,手工制图已不符合现代林业发展要求,正逐渐被淘汰。笔者对应用CorelDrawX3绘制林业工程作业设计图的方法和技巧,包括图框绘制、小班勾绘、着色、求积以及绘图成果打印等进行了详细介绍,容易掌握、色彩丰富、制图效率高。CorelDrawX3是绘制林业工程设计图的实用...     

福建省林木良种繁育概况及今后工作设想

本文介绍了福建省林木种质资源的收集保存、研究利用，优良家系选育，树种内种源研究，高世代种子园研究，乡土树种栽培驯化，外来树种引种，提高种子园种子产量所采取的措施，无性繁殖技术等林木良种繁育概况；并就林木育种工作存在的问题及今后工作设想提出建设性意见。     

A biomechanical analysis of industrial forest plantation workers in East Kalimantan

The objectives of this study are to clarify physiological work loads and physical loads acting on the lumbar region of workers and to propose a safe work environment in tropical forestry operations. The research was conducted in the industrial forest plantations of East Kalimantan, Indonesia, in 1996. In this study, heart rates and the physical lumbar burden of industrial forest plantation workers were measured for three types of work, that is, weeding, planting and path clearing. In addition, the load moment at the L₅/S₁ and the disc compression force were calculated using low-back biomechanical models. As a result, compression forces at the L₅/S₁ disc during weeding, planting and path clearing were estimated and found to be below the Action Limit (AL) by National Institute for Occupational Safety and Health (NIOSH). However, it was also found that some work posture types during path clearing by chain saw were sometimes above the AL. A part of this paper was orally presented at the 108th Annual Meeting of the Japanese Forestry Society (1997).     

Protection of Metasequoia glyptostroboides Hu et Cheng in China

Metasequoia (Metasequoia glyptostroboides Hu et Cheng) is an important but endangered tree species. In a sense, the course of protection of the metasequoia can be considered a miniature of the history of the protection of rare Chinese plants over the past 50 years. The approval and establishment of the National Class Nature Reserve for metasequoia is a milestone in this course. A thorough understanding of this course is beneficial to design the correct future protection plans and for taking effective measures. In this paper the entire protection course of metasequoia is reviewed, three detailed measures are proposed according to the present situation and existing problems and discussed as follows. 1) We should reinforce unceasingly the establishment of National Nature Reserves of metasequoia, put emphasis on the protection of the original natural mother trees (ONMTs) of metasequoia, design farsighted projects to protect the ONMTs and strictly implement and enforce the regulations or laws regarding the protection of metasequoia. The establishment and functions of the organization should meet the demands of protecting the ONMTs and developing metasequoias. The budget should support and the quality of the personnel assigned to this task should satisfy the protection and development of the ONMTs. We should also promote the complete protection of the ONMTs at the same time and strengthen the protection and restoration of the ONMTs and their ecosystem in the Xiaohe valley, Lichuan County, Hubei Province, one of the natural concentration areas of ONMTs in the world. 2) A gene bank should be established for comprehensive protection of the genes of ex-isting original mother trees of metasequoia. 3) The key is to study the theoretical fundamentals of restoration and re-establishment of natural vegetation of metasequoia in the Xiaohe valley to harmonize the relation among environmental departments, forestry sectors, academies of sciences and other educational or research units, to carry out scientific research and strengthen academic exchanges to promote jointly the protection and utilization of metasequoia and other natural resources in China.     

《测量学》试卷库设计与实践

从南京林业大学《测量学》课程教学现状及存在的问题出发,阐述设计《测量学》试卷库的必要性,指出高素质的命题队伍、科学合理的命题准则是试卷库建设的前提条件。修订教学大纲和考试大纲、试题的遴选及试卷的组配是试卷库建设过程中的关键环节,其中,遴选试题包括：题型的选择;试题难度系数的确定;试题区分度系数的确定;试题覆盖面的确定等几个步骤。最后,从试题的科学性和合理性、评阅试卷标准统一、成绩可靠性、不同角度、不同侧面全面考核考生掌握知识的情况等方面对所建设试卷库的特点进行总结。     

“林海雪原·谧静青松”森林旅游开发项目前期工作实践

本文以舒兰“林海雪原·谧静青松”森林旅游开发项目为例,从工作框架、项目区基本情况整理、相关调查工作的组织开展、编制规划的运作、预热及宣传等5个方面介绍了前期需做工作及注意要点。     

杉木中龄林不同部位和叶龄针叶光合特性的日变化和季节变化

在不同季节光合最适温度、适宜空气湿度 (70± 5 % )和正常大气CO2 条件下测定了杉木(Cunninghamialanceolata (Lamb .)Hook .)中龄林不同部位和叶龄针叶光合特性及典型天气下净光合速率的日变化。结果表明 ,当年生针叶最大净光合速率 (Pmax)在生长中期 >盛期 >后期 ,1年生和 2年生针叶则从盛期经中期到后期呈下降趋势。从生长盛期至后期 ,光饱和点 (LSP)和暗呼吸速率 (Rd)降低而表观量子利用效率 (α)增加 ,其中尤以盛期与中后期的差别较明显。光补偿点 (LCP)除生长盛期当年生针叶明显高于生长中、后期以外 ,其它差异不明显。Pmax除生长盛期当年生针叶与 1年生接近外 ,均为当年生 >1年生 >2年生。随着叶龄的增长 ,针叶LSP、LCP和Rd 均降低 ,α提高。从上部至中部到下部针叶Pmax、LSP、LCP和Rd 均降低而α增加 ,尤其是上部和中部针叶与下部差异较大。不同季节针叶光合特性的差异与针叶光合生理活性有关 ;不同部位之间的差异则是长时间适应所处光环境的结果 ;而不同叶龄针叶之间的差异除了生理原因外 ,还可能与所处光环境有关。针叶净光合速率 (Pn)的日变化在阴天为单峰型 ,Pn 主要受光合有效辐射通量密度 (PPFD)的影响 ,同时受温度、湿度和CO2 浓度变化的微调。晴天Pn 日变化为双峰型 ,受温度和湿度的强     

不同强度人为干扰对马尾松生长的影响

不同强度人为干扰15a后,经解析木分析表明,轻度干扰林分中马尾松的胸径、树高、材积均保持良好的生长趋势,总生长量比中度干扰和重度干扰林分高,连年生长量和平均生长量在幼龄期也高于后二者,重度干扰林分的各要素生长量均增长缓慢。这些结果表明超过一定限度的人为干扰阻碍了林木的生长发育。