1STZ-25型上树采种(果)设备的研究与设计

介绍了一种研制开发的新型上树采种设备，该设备适用于我国广大林区不同树高和多种立地条件的采种、采果作业。     

高大树上树设备的研究

在积极吸收欧美林业发达国家采种先进技术的基础上，研究出来的１ＳＴＺ－２５型上树设备，是一种适用于我国广大林区不同树高和多种产地条件的采种上树设备。文章介绍了设备结构及设计参数。     

第一部分 营林机具

SZ—1型采种上树机具一、用途主要用于采种时帮助采种者上树,尚可用于架设架空索道或采集标本等需要上树的作业。本机具在山区、平原和疏林、密林内对针阔叶树都能使用,但使用时需要两人协作。图2为用 SZ—1型采种上树机具上树时的示意图。     

林区育苗用种问题

(一) 内蒙古大兴安岭林区近几年来兴安落叶松种子供不应求,从区外引进调购的树种不断增加,产地多,种籽混杂。由于近年来内蒙古大兴安岭林区气候变化大,常遭冻害,病虫害也较严重。加之历年来采种对母树的破坏,使种子产量降低,质量变差。同时,林区的良种基地始终没有建立起来,育苗用种主要靠天然林采种,有些人对于育苗用种存在一种偏见,忽视乡土树     

介绍一种简易采种工具

在全面大跃进和总路线的光辉照耀下,国家要求我们把所有的种子完至采集下来,这是一件艰巨而伟大的工作。怎样做到既要把树上的种子全部采下,又要保证人身和母树的安全,减少上树费时、费衣,提高采种效率,从而在采种工作中达到多快好省的要求,关键在于首先从改革工具着手。九年来各地用的采种剪、钩、刀等工具也发生了一定的效用,但由于果实(荚果和蒴果)在树干上生长的位置不     

杜仲栽培技术及开发利用

杜仲在甘肃省嘉陵江上游、白龙江下游的小陇山林区有天然分布，它适宜生长在土层深厚、肥沃湿润的微酸性土壤中，喜光、耐低温及干旱，在浅山及平原地区生长发育良好。１育苗技术１１播种育苗选择生长发育良好、无病虫害的母树采种。种子一般在１０～１１月采收，然后放...     

优质香椿实生苗的繁殖技术

以往香椿主要靠根蘖繁殖 ,其优点是生长迅速 ,并能保持母本的优良形状 ;缺点是产苗数量有限 ,难于满足大面积造林的需要。近年来推广了香椿实生苗的繁殖方法 ,为大面积造林提供了可能。1　采种母树的选择与管理1.1　采种母树的选择首先 ,应选择生长健壮、发育良好、无病虫害、15～ 3 0年生的壮年植株为采种母树。其次 ,采种树的选择还应根据造林目的而定。作为菜食用林 ,应选择树形低矮 ,分枝力强 ,枝条生长缓慢 ,芽体粗壮、肥嫩的品种。作为材用林 ,应选择生长迅速 ,树干高大、通直、材质好的品种。1.2　采种母树的管理首先 ,被选作采种母…     

油桐开花座果生物学特征的调查研究

经研究,油桐自然在果率较高,自交座果率随树龄增大而下降,采种母树年龄以12—15年为宜。雌花开放后,第1—10天均能授粉座果,其中前3天授粉效果最好。     

银杏育苗及造林技术

银杏育苗及造林技术山西省造林局许鹏１．苗木培育银杏苗木繁殖方法有种子繁殖、扦插、嫁接、压条和分株等。１．１．种子繁殖１．１．１．采种母树的造择：选择立地条件好，生长健壮，果大仁饱的成年树作为采种母树，进行采种。从外地引种时。应注意引进优良品种，如大梅...     

国槐采种与种子加工技术

国槐采种与种子加工技术刘新元国槐是我国栽培历史悠久的优良树种，它具有材质优、用途广、寿命长、适应性强等优点。其采种与种子加工技术如下：１、选择母树。要选择树龄在２０—３０年生的，材质优良，生长良好，树干通直，无病虫害，结果穗大荚多的树木作为母树。２、...     

采种技术及其微型动力采摘设备的研究

从我国山地林区采种特点出发,针对采种作业中存在的技术难题,首次提出了能适应多树种的林木种子高效采摘技术新方案,并完成了其微型动力采摘设备的研究。     

陡坡地采伐归堆机的研究设计

针对我国北方林区采伐机械的作业特点，研制出一种适合复杂林地条件下的陡坡地小径木采伐归堆机。该机装有带车轮、可液压调整的一对后支腿和带有底板的一对前稳定支腿，其可在陡坡山地和沼泽地环境下作业，尤其适用于陡坡山地的采伐集材作业，是一种比较理想的作业设备。     

海南霸王岭陆均松类热带山地雨林伐后林结构与物种多样性研究

霸王岭林区是海南岛最典型的热带山地雨林分布区.在该区,现存分布面积最广、资源数量最大的是热带山地雨林的各种伐后林.以霸王岭分布最广的以陆均松(Dacridium pierrii)为主的山地雨林的伐后林为对象,研究了其组成、径级、高度结构和物种多样性特征,对比分析了伐后林与原始林以及伐后林不同类型之间的异同.结果表明:原始热带山地雨林经采伐后中小乔木和灌木的优势度增大,而大乔木树种的优势度则明显下降.阳性树种的种类、数量和相对重要性随采伐破坏的程度而增加.伐后林中矮、小树木在林分中比例随采伐破坏的程度增加,而高、大树木,特别是进入主林层树木的比例则随采伐破坏的程度明显下降.从林分测树因子的变化来看,采育择伐和径级择伐的林分要优于大强度择伐和皆伐的林分.原始林的物种丰富度大于伐后林,但其多样性指数和均匀度指数大都小于伐后林.组成上与原始林相似性较大的伐后林是各种择伐后的林分,而皆伐后的林分与原始林在组成上已有很大差别.     

Ecological and economical sustainability assessment of community forest management in Nepal: A reality check

This study analyzes the sustainability of community forest management, representing four forest types of two physiographic region Hills and Terai of Nepal. We assess the sustainability based on species composition, stand density, growing stock volume, and growth-to-removal ratio using inventory data of 109 permanent forest plots from four consecutive intervals of three to five years. In addition, forest users, forest committee members, and forest officials were consulted. We observed increment on the representation of economically valuable tree species in all forest types of both regions. The pole-size tree dominates in all forest types with declining number of trees and regeneration. In case of Hills forests, they were over-harvested until 2013 but were under-harvested in the recent period. In contrary, forests were under-harvested in the Terai. We found that ecological objectives of sustainable management are fully achieved while economic benefits remained unharnessed where harvesting is far below the growth. We conclude that maintaining a large number of trees may contribute to ecological but not on economical sustainability. We argue to rationalize annual harvest in all categories of the forest to enhance resource conditions together with regular benefits to the local communities.     

Analytical model of carbon storage in the trees, soils, and wood products of managed forests

The carbon balance between managed forests and the atmosphere depends critically on the frequency and intensity of harvesting, and the lifetime of harvested products. To assess more quantitatively the nature of this dependence, a theoretical analysis, previously applied to carbon storage in trees and wood products only, is extended here to include the carbon in forest floor detritus and soil. A dimensionless combination of the parameters of the model, alpha, with critical value alpha(c), is identified such that for alpha < alpha(c), the conversion of old-growth forest to managed forest releases carbon to the atmosphere in the long term. Parameter alpha is given by the combination f(t)D/T(*), where f(t) is the fraction of old-growth forest carbon stored in trees, D is the residence time of harvested biomass (wood products and slash debris) within the system, and T(*) is the rotation period for maximum sustained yield (maximum mean annual increment). The critical value alpha(c), typically in the range 0.5-0.7, is derived for a variety of forest types. Parameter alpha determines the degree to which the carbon accumulated in harvested biomass offsets the loss of carbon in trees due to felling and in soils due to reduced litter input. When alpha > alpha(c), long-term carbon storage is optimized by harvesting for maximum sustained yield.     

哀牢山湿性常绿阔叶林木质藤本植物的物种多样性及其与支柱木的关系

分别在哀牢山湿性常绿阔叶林沟谷和坡面调查了10个20m×50m的样地,研究哀牢山湿性常绿阔叶林木质藤本植物的物种多样性及其与支柱木的关系。结果表明:研究区共记录到DBH≥1cm的木质藤本植物402株(隶属于23种21属16科)和DBH≥10cm的林木1522株(隶属于47种30属15科);与其他亚热带森林比较,该森林中木质藤本植物物种较为丰富但多度较低;藤本植物的物种丰富度、密度和基面积在沟谷显著高于坡面,而林木的差异性不显著;木质藤本植物在支柱木上呈集群分布,并且不同种支柱木被藤本植物攀援的百分比间存在显著的差异(P0.001),说明藤本植物的攀援对支柱木具有选择性;云南越桔、薄叶马银花和景东冬青等树种因其树皮光滑而不易被藤本植物攀援,而腾冲栲、七裂槭、山矾和多花山矾等则易于被藤本植物攀援;大径级支柱木被藤本植物攀援的比率高于小径级支柱木;茎缠绕和钩刺攀援藤本的胸径与支柱木胸径极显著相关(P0.001),根攀援和卷须攀援藤本的胸径与支柱木胸径相关性不显著(P0.05)。     

伐区调查设计对森林采伐量的影响

研究分析伐区调查设计对森林采伐量的影响,主要有三个方面：①伐区调查设计过程对森林采伐量精度的影响,树木胸高确认不同,森林采伐量误差值越大;调查人员测量胸径时所站位置不同,其森林采伐量也不一样;立木所处地形及不同测量工具和调查设计人员,其测量结果都有影响;②枯立木、风倒木对森林采伐量精度的影响;③伐区调查设计规程对森林采伐量精度的影响。总结目前伐区调查设计中存在的问题,寻找提高采伐量精度的方法,为今后伐区的合理的调查设计以及采伐作业提供理论依据。     

棕榈藤采收方法与新型采藤机械的研制

棕榈藤自身生长特性、形态特征使得采收工作十分困难。棕榈藤的采收分人工和机械采收。传统的藤采收方法采收工作效率低,劳动强度大,藤材采收损耗大,甚至对树木造成损毁。文章介绍了藤采收技术的最新研究成果,并对棕榈藤采收方法的改进提出了建议。     

A review of breeding drought resistant Casuarina for shelterbelt establishment in arid regions with special reference to Egypt

Drought resistant forest trees are essential for the establishment of protection plantations in arid and semi-arid regions. Some members of the family Casuarinaceae are considered as prime candidates for such a task. In spite of their superior qualities as shelterbelts, as a source of fuel wood and in soil rehabilitation, casuarinas are among the least exploited forest trees.This article reviews the recent developments in breeding for drought resistance in woody trees and the criteria generally used for screening tolerant taxa. The Casuarina breeding programme undertaken by Alexandria University is described and some of the early results are reviewed.     

Towards a DNA marker assisted seed source identification: a pilot study in European beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis> L.)

The widespread European forest tree Fagus sylvatica L. is of great importance for forest management. However, information about seed dispersal is still very rare, though important for harvesting strategies and later on seed source identification. We refined a DNA fingerprinting method for beech nut shells in order to directly assign dispersed seeds to their mother trees. A pilot study was conducted in two beech stands in Germany where leaves of the adult trees and the exocarp of dispersed seeds were fingerprinted at six nSSR loci. While one stand was randomly analysed for adults and dispersed seeds the other was systematically investigated following common harvesting procedures. Imitating the typical net harvesting strategy, seeds were collected beneath 19 adult trees. Exocarp genotyping revealed that on average three different mother trees contributed to a sample of five or six seeds collected beneath a single adult tree. Of the identified mother trees most were located within a radius of 15 m from the sampling point. The repeated pattern of seed dispersal within a short distance constitutes the basis for a straightforward strategy for the assignment of seed lots to a seed source stand. This strategy is based on the matching of individual genotypes without the necessity for a full inventory of the putative source stand. Additionally, we provide allelic ladders of five nSSR loci for standardization among laboratories.