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调整松林密度控制清源山松突圆蚧危害的试验 总被引:5,自引:0,他引:5
通过对发生区内松林进行间伐、修枝等营林措施将郁闭度调整至0 5左右,松林中松突圆蚧的虫口密度从调整松林密度前的每束2 61头下降至0 63头,虫口密度下降75 86%,表明调整松林密度能有效地控制松突圆蚧对松林的危害;同时发现,阳坡上松林的虫口密度较阴坡上松林的虫口密度大,从阳坡向阴坡逐步过渡,松突圆蚧的虫口密度也随之下降,表明松突圆蚧的虫口密度与坡向有关,在景区绿化规划设计上应针对不同的坡向营造不同的树种,以防止松突圆蚧的发生和危害。 相似文献
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采用样点调查法对不同程度马尾松毛虫危害松林的植被群落进行了调查。结果表明:不同程度马尾松毛虫危害对松林林分密度的影响不显著,但对松树生长量有着不同程度的影响,中、重度危害可降低松树的高度和胸径(重度危害三年后高度、胸径分别下降0.34 m和1.8 cm),轻度危害则可促进松林的生长;马尾松毛虫危害可适度改变松林的郁闭度和地表植被的盖度(中、重度危害后三年盖度分别上升15%和20%),对林下植被的恢复与生长有一定的促进作用;松林植被物种多样性分析表明,中、重度马尾松毛虫危害可有效增加林地植被物种的多样性,轻度危害则对林地植被物种多样性影响不大。 相似文献
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通过套种造林、封山育林、抚育改造等措施,将马尾松纯林改造成针阔混交林,以改变树种结构单一、地力日益衰退、病虫害逐年严重、林地灌木杂草丛生、火灾频繁发生、林分产量低下等状况。结果表明:在松林下套种阔叶树,可不同程度增加单位面积阔叶树数量,形成明显的层次结构,能充分利用林地中的营养空间,马尾松和阀叶树在各自不同层次生长范围... 相似文献
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According to a great deal of field investigation and detailed indoor analysis, the natural regeneration pattern and process
of Korean pine population under natural Poplar-birch forest has been uncovered. The results show that the regeneration quantity
and quality of Korean pine population under mountainous Poplar-birch forest and mountainous white birch forest are better
than those under valley moss-grass White Birch forest and virgin broad-leaved Korean pine forest. Korean pine population shows
aggregated distribution, the mass-occurrence period of Korean pine population is behind the mass-occurrence period of Poplar-birch
population. Various aged Korean pines growth is affected by different stand structure factors. Man-made lighting tending can
accelerate the regeneration process and increase the regeneration quality of Korean pine population. It is feasible to set
up regeneration recombination of upper layer White Birch and lower layer Korean pines. 相似文献
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光热和水分条件对石灰岩山地侧柏人工林更新的影响 总被引:1,自引:0,他引:1
侧柏(Platycladus orientalis)是我国荒山造林、水土保持和涵养水源的重要常绿树种之一。它适应环境的能力强,栽培范围广,常被栽植于我国的石灰岩山地上。耐干旱瘠薄是公认的侧柏生态学特性之一,但是,侧柏幼苗和幼树的更新和生长受山地环境影响较大。通过热红外成像法移动观测山体光热能量的分配特征,利用SketchUP软件三维阴影分析的功能进行林窗日照和遮阴分布的计算机模拟,以及在山东省侧柏主要栽培区对山地林窗幼苗进行实地调查研究,结果表明:侧柏苗适合栽培在湿润而光照充足的立地上。山地阴坡和阳坡、山谷和山脊的光照和湿度的差异导致侧柏幼苗更新的变化,以至于一边因密度过大而出现严重的种内竞争,另一边因幼苗更新不畅而常出现林窗和空地。因此,需要通过适度的人工抚育和管理来解决该问题,以便在我国北方地区建立起稳定和完善的侧柏森林生态系统。 相似文献
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Broad-lcafKorcanpi11cforcstbccol11csPoplar-bircl1forcstaftcrburntandfcllcdinbigarcas.Ca11tl1iskindofPopIar-bircl1forcstrccot'crtoclin1axco1nl11unity-trirginbroadlcafKorcanpincforcst9Whatistl1erclationsl1ipbctt`.ccnPoplar-birchforcstandKorcanpil1cforcst?Ho`"docsKorcanpincPOpu1ationrc-gencratcundcrnaturaIPoplar-birchforcst?AllthescprobICInsl1a\'caIrcad}'attractcdforcstcrsattcntionforaIOI1gtil11c.Tllccarh'studicsshox'cd:itt'asinct-ita-blcthatbirchforcstcouldfonnonbun1ingsitesx"ithil1t'irg… 相似文献
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Mountain pine beetle, Dendroctonus ponderosae Hopkins can cause extensive tree mortality in ponderosa pine, Pinus ponderosa Dougl. ex Laws., forests in the Black Hills of South Dakota and Wyoming. Most studies that have examined stand susceptibility to mountain pine beetle have been conducted in even-aged stands. Land managers increasingly practice uneven-aged management. We established 84 clusters of four plots, one where bark beetle-caused mortality was present and three uninfested plots. For all plot trees we recorded species, tree diameter, and crown position and for ponderosa pine whether they were killed or infested by mountain pine beetle. Elevation, slope, and aspect were also recorded. We used classification trees to model the likelihood of bark beetle attack based on plot and site variables. The probability of individual tree attack within the infested plots was estimated using logistic regression. Basal area of ponderosa pine in trees ≥25.4 cm in diameter at breast height (dbh) and ponderosa pine stand density index were correlated with mountain pine beetle attack. Regression trees and linear regression indicated that the amount of observed tree mortality was associated with initial ponderosa pine basal area and ponderosa pine stand density index. Infested stands had higher total and ponderosa pine basal area, total and ponderosa pine stand density index, and ponderosa pine basal area in trees ≥25.4 cm dbh. The probability of individual tree attack within infested plots was positively correlated with tree diameter with ponderosa pine stand density index modifying the relationship. A tree of a given size was more likely to be attacked in a denser stand. We conclude that stands with higher ponderosa pine basal area in trees >25.4 cm and ponderosa pine stand density index are correlated with an increased likelihood of mountain pine beetle bark beetle attack. Information form this study will help forest managers in the identification of uneven-aged stands with a higher likelihood of bark beetle attack and expected levels of tree mortality. 相似文献
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闽北山地坡相对湿地松人工林木材化学成分的影响 总被引:1,自引:0,他引:1
应用坡相四个因子在两个水平下的正交试验设计方法,系统分析了19年生湿地松人工林木材化学成分的变化规律,结果表明:影响湿地松人工林木材化学成分的最重要坡相因子是坡形,其次是坡位,再者是坡向,小于45°的坡度的影响可忽略不计。湿地松人工林木材作为纸浆原料和人造板原料,阴坡好于阳坡,凸坡好于凹坡,上坡好于下坡。 相似文献
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IntroductionAgestructureoftrees,whichreflcctsrcge11eratio11processandvelocity,meansquantityoftreesdividingbyage.Broad-leavedKoreanpineforestwastl1etypicalzol1alvegetationofChangbaiMountaininNortheastO1ina,anditwastheprimarygymnospermconununitysurvivedaftertheQuatemaryGlacierPeriod.Alotofcommunityinf`)r-mationaccumulatCdinthestr-uctllreofforeststandsa11dgrowingprocessofindividualtrees.So,athoroughstUdyonagestructureanditsdistributiol1ofbroad-leavedKore-anpine.forestwouldprovidetl1eoretical… 相似文献
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报道了黄山风景区松蛀虫种类、主要松蛀虫成虫活动期、种间种群数量比率和种内种群数量垂直分布比率 ,2 0 0 1年 5种松蛀虫成虫种群数量变动规律、不同监测期松墨天牛雌成虫孕卵量及比率。研究结果表明 ,黄山风景区繁衍着 14种松蛀虫 ,主要松蛀虫有 5种 :马尾松角胫象、松墨天牛、短角幽天牛、褐幽天牛、松树皮象。其种群数量比率分别为 6 1.6 %、2 7.0 %、5 .5 %、3.8%和 2 .2 %。松墨天牛成虫最高分布区为海拔 16 5 8m的天海景点 ,海拔 318m的白亭景点种群数量分布比率最高 ,达80 .9% ,诱获的松墨天牛雌成虫平均孕卵量为 2 5 .3粒 相似文献