豫北飞播油松林区生物防火工程措施探讨

通过对飞播油松林实话抚育间伐,清除林内可燃物,在疏林及林中空地补植补造阔叶树种,营造阔叶树种防火林带等生物工程措施,可降低林分的燃烧性,提高林分抗火阻火能力。     

豫北飞播油松林区的生物防火工程措施

通过对飞播油松林实施抚育间伐、清除林内可燃物、在疏林及林中空地补植阔叶树种、营造阔叶树种防火林带等生物工程措施 ,可降低林分的燃烧性 ,提高林分抗火阻火能力     

马尾松林分间伐套种质量提升研究

对马尾松(Pinus massoniana)林分在第12年、第20年进行人工间伐,并进行补植套种7个阔叶树种:灰木莲(Manglietia glauca)、枫香(Liquidambar formosana)、樟树(Cinnamomum camphora)、楝叶吴茱萸(Evodia meliaefolia)、木荷(Schima superba)、火力楠(Michelia macclurei)、红锥(Castanopsis hystrix)。12 a生马尾松间伐前林分平均树高9.22 m,平均胸径14.3 cm,平均材积99.9 m3/hm~2,第1次间伐后经过8年生长,林分平均树高比间伐后保留木增加5.53 m;平均胸径增加7.64 cm;平均材积增加149.55 m3/hm~2。阔叶树补植套种2.5 a后平均高3.2 m,平均地径4.47 cm。通过间伐套种,马尾松林分保留木生长质量得到提升,套种7个阔叶树前期生长良好。     

低丘马尾松林相改造中的阔叶树种选择

为改造低丘马尾松纯林,进行了14种阔叶树的补植试验。栽后4年调查高生长、成活率、抗病虫性三个因子,应用Fuzzy非线性规划原理进行综合评判,认为酸枣和美国木荷的效果较理想。     

浙江安吉退化毛竹林改为竹阔混交林模式初探

为提高退化毛竹纯林的生态价值，重建森林生态系统，结合安吉县培育珍贵树种、营造彩色森林建设目标，试点研究了将安吉退化毛竹纯林改造成彩色林分或竹阔混交林的具体模式。结果显示，退化毛竹林通过采用留养抚育、适度透光间伐、适当清理林下灌木、补植乡土珍贵树种等方法改造后，阔叶树种均生长良好。     

基于Voronoi图与Delaunay三角网的杉木人工纯林林木补植位置与空间配置

杉木人工纯林被划归为生态公益林,为了提高物种多样性,在杉木纯林内补植阔叶树种是多功能经营的一种有效手段。为了在杉木人工纯林林木补植时尽可能优化林分空间结构,本文提出基于Voronoi图与Delaunay三角网的补植位置与空间配置方法。以林木个体所在空间位置为平面相异点构建Voronoi图和Delaunay三角网,Voronoi图量化对象木的K-阶邻近关系,Delaunay三角网确定相邻木间的距离、角度和林木间的林隙。考虑林分的水平空间结构,选取基于Voronoi图的变异系数、混交度和竞争指数分别描述林木的分布格局、混交程度和竞争关系,建立林木和林分空间结构调控的均质性目标。林木补植前进行两株萌生木与枯死木的抚育间伐,补植分两次进行,第一次补植栾树,马褂木,第二次补植观光木,依据林木间Delaunay三角形面积大小确定林木补植位置,依据K阶邻近林木关系进行补植林木的空间配置,以达到林分空间结构优化的目的。因为研究对象为杉木人工纯林,补植前林分的树种混交度很低,介于0.011~0.063,由于属于杉木幼龄,还没有郁闭,竞争指数介于0.699~0.833,竞争强度较小,基于V图的林木分布变异系数介于1.662~2.354;林木补植后林分树种混交度得到提高,第二次补植后树种混交度(0.191±0.007)比第一次补植后的树种混交度(0.186±0.005)有所提高,均明显大于补植前树种混交度(0.042±0.020),补植后不仅物种多样性增强,树种混交程度增强;补植后竞争指数增大,第二次补植后林分竞争指数(4.67±0.32)比第一次补植后林分的竞争指数(4.41±0.24)有提高,均大于补植前林分的竞争指数(3.92±0.20),表明补植后竞争强度增强;第二次补植后基于Voronoi图的变异系数(0.48±0.07)比第一次补植后基于Voronoi图的变异系数(0.55±0.10)降低,均小于补植前基于Voronoi图的变异系数(2.04±0.31),表明补植后空间分布更均匀。基于Delaunay三角网进行林木补植能够调整林木的空间分布,基于K阶邻近的林木补植空间配置能够尽可能提高补植林木混交度与林分混交度,且补植树种越多,混交度越大,本文提出的林木补植方法可以实现林木补植在提高生物多样性同时优化林分空间结构。本研究为林分空间结构调整与优化林木补植提供理论依据,促使杉木人工纯林导向近自然林,实现多功能的森林经营。     

阔叶树容器苗造林

绿化造林,美化家园是我们永垣的主题。在绿化造林工作中,我们时常会遇到这样的问题,那就是由于种植时连续天晴或苗木调剂等诸多因素造成成活率达不到规定要求,特别是常绿阔叶树造林要达到很高的成活率本身存在一定的难度。如果成活率不足,想要当年再造林或补植,却又错过造林黄金季节,结果是错过一春贻误一年。以前我们采用湿地松容器苗春季造林、秋季造林或补植,取得了良好的效果。我们在2004年培育阔叶容器苗造林也取得了良好的成效。为延长造林季节和提高常绿阔叶树造林成活率提供了保障。1.常绿阔叶容器苗的培育(以香樟、山杜英为例)材料…     

马尾松纯林改造技术初探

结合近自然理论进行马尾松纯林改造，每667m2选定20～25株作为母树，采取择伐和疏伐相结合，适当补植阔叶树，促进林木生长和生物多样性。通过间伐强度采取20％、40％和对照试验，结果表明：通过间伐马尾松林分，均能促进林木生长，增强林分抗逆性，有利于土壤改良，其中40％的间伐强度更有利于林分形成混交复层林，提高生物多样性。     

开展雨季补植是提高造林成活率与保存率的有效措施

本文介绍了开展雨季补植的意义，雨季补植的具体做法，雨季补植成果调节及几点体会。     

杨树造林宜留补植苗

杨树造林宜留补植苗为使杨树林相整齐，补植苗生长迅速，应在造林前预留１５％—２０％的苗木作将来补植苗。方法：（１）贮存补植苗。冬春季造林后，按照造林总株数的１５％—２０％选留补植苗进行临时假植，单株排列，灌足水。待确定成活率后补植。（２）留床苗补植。造...     

Abundance and use of cavity trees at the tree- and stand-levels in natural and plantation forests in Hokkaido, Japan

The conservation of cavity trees in plantations is important for maintaining biodiversity because cavity trees are one of the forest attributes most strongly affected by forestry operations. We surveyed the occurrence of cavities at the tree-level and the abundance of cavity trees and the number of uses by secondary cavity users at the stand-level in natural and conifer plantation forests in Hokkaido, Japan. We classified cavities into two types by their formation processes: excavated and non-excavated. Excavated cavities were more common in dead trees than in live trees. Non-excavated cavities showed high occurrence in dead and live broad-leaved trees. The abundance of non-excavated cavity trees was two times greater than that of excavated cavity trees in natural forests, but, in plantations, excavated cavity trees were dominant. The abundance of non-excavated cavity trees was lower in thinned plantations than in not-thinned plantations. The number of cavity uses increased with the number of cavity trees, indicating the importance of maintaining cavity trees. Conifer plantations are established by removing native broad-leaved trees, which results in a lower abundance of non-excavated cavity trees in these locations. The conservation of broad-leaved trees is important for maintaining the current and future resource of non-excavated cavity trees in plantation forests, as is the conservation of dead trees, which showed a high occurrence of excavated cavities.     

兴安落叶松过伐林枯立木分布格局特征分析

以内蒙古根河林业局潮查林场境内的在20世纪80年代初主伐利用后形成的兴安落叶松过伐林为研究对象,利用兴安落叶松林8块标准地每木定位数据,分析林木分布格局和样方(5 m×5 m)林木株数对枯立木株数影响,探讨了林分大树和更新幼树位置与枯立木位置的关系,阐明了枯立木分布格局形成机制。结果表明:1)各树种枯立木比例,随树种组成成数增加而增大。枯立木主要在更新幼树阶段形成,径级分布集中在4径阶以下,其株数占总数的比例平均达82.2%。在更新幼树(含枯立木)中,生成枯立木的比例平均达8.8%。2)枯立木分布格局为聚集分布。林木分布格局、样方林木株数和更新株数与枯立木株数有显著正相关关系,林木分布格局对枯立木分布格局无显著影响。林木聚集度越大,形成枯立木的可能性越大,数量也就越多。3)枯立木位置与更新幼树和大树位置有显著相关关系。主要表现为落叶松和白桦相互关系。枯立木出现位置主要在大树和更新幼树集聚区域。大树对枯立木形成影响较更新幼树大,而且均以落叶松较白桦明显。白桦更新幼树对落叶松枯立木的形成,无显著影响。受影响的枯立木主要是枯立木株数中所占比例和树种组成成数较高的树种。影响枯立木位置的林木主要取决于其样方内位置和林木株数。     

酸雨对杨树生长和木材化学性质的影响

对受酸雨危害和未受酸雨危害杨树的年轮宽度和木材化学性质的对比研究表明：酸雨对杨树生长和木材化学性质产生了明显的影响。酸雨会导致树木生长减缓,年轮宽度变窄,受害材的年轮宽度较健康材相对降低１２．６７％。受害材与健康材的ｐＨ值无明显差异,酸、碱缓冲容量有显著差异。与健康材相比,受害材的戊聚糖和木质素含量相对升高１．４３％和３．７２％,而综纤维素的含量相对减少３．４５％,灰分的含量相对减少８．３４％。受     

南昌园林彩叶树种种类与应用

通过系统调查查明南昌彩叶树种共有114种,主要分为春色叶、秋色叶、常色叶、双面叶、斑色叶5类。探讨它们在南昌市区的主要应用形式。     

Growing situation of afforested trees and damage to lower-story trees caused by felling in multi-storied forest management in Peninsular Malaysia

The growing condition of afforestation trees and damage to lower-story trees caused by felling and hauling of upper-story trees in a multi-storied forest in Peninsular Malaysia was surveyed. Seventy months have passed since the planting ofAcacia mangium upperstory trees, which have grown 233 m³/ha in volume. The growth ofShorea leprosula thirty-five months after planting of lower-story trees have reached 5.54 m in height. However, as the ratio of height to basal diameter exceeds 100:1, trees are tapering to a considerable degree. A backhoe was installed in order to fell the upper-story trees. From the results of logging, the damage ratio estimation of the lower-story trees was simulated by using the Monte Carlo method. The damage ratio differed considerably depending on planting patterns, height of upper-story trees and felling skills. The results of this survey proved that the felling and hauling of upper-story trees would be technically feasible in the future, except when one row upper-story trees and one row lower-story trees method were employed.     

大兴安岭兴安落叶松林林隙更新研究

研究了大兴安岭地区不同林型林隙的更新密度、边缘木数量及形成原因,结果表明:1)林隙一般由11~24株落叶松、白桦所形成,平均为16.94株;形成方式主要有立枯、折干和拔根倒,11.8%为折干,35.3%为立枯,41.2%为拔根倒。2)林隙所在坡位中58.9%为中下和下坡位,41.1%为中上坡位。3)在杜香-落叶松林、草类-落叶松林和藓类-落叶松林更新密度所受到的制约因子不同,杜香-落叶松林的林隙更新主要受坡度的影响,草类-落叶松林的林隙更新主要受长短轴比的影响,藓类-落叶松林的林隙更新主要受边缘木数量的影响。     

昆明昙华寺公园园林植物群落结构分析

采用典型抽样的方法对昆明昙华寺公园中的前园与中园、后园的园林植物群落进行物种结构、水平结构、垂直结构和季相的调查与分析。前园共有植物73种,分属于40科、63属。中园共有植物73种,分属于38科、53属。前园树种丰富度为6.32,树种多样性指数为3.45。中园树种丰富度为5.56,树种多样性指数为3.39。后园树种丰富度为5.94,树种多样性指数为3.34。中园胸径超过3 cm,冠幅超过9 m所占总数的百分比远比其它园区多的多。前园与中园乔木树高主要集中在10.7 m以上,后园树高在4.6~10.7 m的最多。3个园区的园林植物群落季相变化都不是很明显。     

酸雨对杨树木材性质的影响

受酸雨危害和未受酸雨危害的杨树木材性质的对比表明：酸雨对杨树生长和木材性质产生显著的影响。与未受危害的健康材相比,危害材的木素和戊聚糖含量相对升高３．７２％和１．４３％,而综纤维素的含量相对减少３．４５％,热水抽出热,苯－醇抽出物和１％ＮａＯＨ抽出物含量明显高于健康材。     

长沙市古树名木资源及其保护对策

据调查,长沙市建档树龄100年以上的古树名木1265株,分属34科54属69种。其中一级古树23株,二级古树51株,三级古树1191株,属最多的科是蝶形花科,有4属。种最多的科是壳斗科,有6种。株数最多的树种是香樟,有438株,其次是枫香,有250株,两者累计占全市古树名木总株数的54.39%。资源最多的是岳麓区,有714株,占全市总株数长沙市古树名木资源及其保护对策的56.44%。利用MAPINFO PROFESSIONAL地理信息系统软件为平台,建立了长沙市古树名木资源动态管理系统,为古树名木的保护奠定了基础。针对存在的问题,提出了全市古树名木的保护对策。       

Development of tree hollows in pedunculate oak (Quercus robur)

Many invertebrates, birds and mammals are dependent on hollow trees. For landscape planning that aims at persistence of species inhabiting hollow trees it is crucial to understand the development of such trees. In this study we constructed an individual-based simulation model to predict diameter distribution and formation of hollows in oak tree populations. Based on tree ring data from individual trees, we estimated the ages when hollow formation commences for pedunculate oak (Quercus robur) in southeast Sweden. At ages of about 200–300 years, 50% of the trees had hollows. Among trees <100 years old, less than 1% had hollows, while all >400-year-old trees had hollows. Hollows formed at earlier ages in fast-growing trees than in slow-growing trees, which may be because hollows are formed when big branches shed, and branches are thicker on fast-growing trees in comparison to slow-growing trees of the same age. The simulation model was evaluated by predicting the frequency of presence of hollows in relation to tree size in seven oak stands in the study area. The evaluation suggested that future studies should focus on tree mortality at different conditions. Tree ring methods on individual trees are useful in studies on development of hollow trees as they allow analysis of the variability in time for hollow formation among trees.