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为加强对九华山古树名木保护,更加有效地保护九华山森林景观资源,去年底,九华山农村工作处聘请树木病虫害、树木分类、土壤环境和园林规划专家对九华山风景区古树名木进行了实地调查和梳理,不仅查清了风景区古树名木资源状况,而且对所有古树名木进行了“体检”,建立了档案。 相似文献
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根据近年对淳安县的古树名木调查，该县古树名木资源丰富，百年以上的古树名木约4463株，地理成分复杂，古老残遗树种多，中国特有成分多。主要分布在低海拔的乡村旁，大多生长较好，也有部分濒临死亡或已经死亡，必须采取措施加强对古树名木的保护管理。 相似文献
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依据宝鸡市2008年古树名木普查建档调查成果,概述了宝鸡市古树名木的数量、种类、树龄、分布、生长等情况,分析了宝鸡市古树名木衰败死亡原因,提出了较为可行的保护对策. 相似文献
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对山西古树名木生长衰弱原因及其环境状况进行的调查发现,是人为活动导致古树名木生存条件恶化,引起古树名木衰弱和死亡。为保护现有古树名木资源,在借鉴其他地区古树名木保护复壮成功经验的基础上,文中提出应从土壤环境改良、地上树体保护、树体支撑加固、修补树洞等方面入手进行古树保护,定期进行理化性质营养成份的测定,以掌握和分析古树生长的各项环境指标。
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湘西古树名木为何剧减 总被引：1，自引：0，他引：1
湘西自治州位于湖南省的西北部,地处云贵高原的东缘武陵山区,森林资源丰富,林木种类繁多,有大量的古树名木。过去,大量的古树名木出现了衰亡和遭到毁损。最近,我们对湘西古树名木毁损的原因进行了调查,大致可分为三类:一是自然枯死,二是自然灾害袭击,三是人为的摧毁。 由于自然环境发生变化和生境的变迁,古树树龄不断增大,一部分古树由于适应不了变化的环境,出现自然死亡,其数量仅占所调查的古树名木数的1％。 相似文献
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采用逐株、逐片调查的方法,对淄博市的古树名木资源进行了首次全面系统的调查。在调查的基础上,对古树名木树种、数量、生长状况、分布情况、树龄与保护级别等进行了分析研究,建立了古树名木档案,并提出了保护管理措施。结果表明,现存古树名木497株,古树名木群4片,隶属24科、36属、43种,其中一级古树名木227株,二级古树名木270株。 相似文献
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宿迁市古树名木的调查 总被引：1，自引：0，他引：1
宿迁市古树名木的调查张用宪（宿迁市林果技术指导站，２２３８００）古树名木是有生命的活文物和重要的风景资源，是大自然留给人类的宝贵财富。进行古树名木的调查，既可丰富地方文史资料，又有利于未来的科学研究。为此，笔者对本市的古树名木进行了调查。１调查时间、... 相似文献
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泰山古树衰弱死亡原因及保护措施 总被引：1，自引：0，他引：1
据调查,泰山现有古树总数为18 198株。其中,正常古树占25.4%,轻衰和中衰古树占古树总数的63.7%,重衰和濒危古树所占比例为9%,死亡古树比例达到1.3%,急需保护古树935株。对187株死亡古树的死亡原因分析结果表明,古树自然死亡比例为2.7%,病虫害致使古树衰弱死亡比例为42.8%,工程建设破坏(建筑施工、修路、水泥硬化等)致死比例为25.7%,污水污物(厕所污染,建筑、生活垃圾)致死比例为8.6%,郁闭致死比例为6.4%。分析查找古树衰弱及死亡原因,采取相应的古树保护措施至关重要。
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Thinning treatments in second-growth forest may be a practical means of accelerating the development of certain old-growth structural features in regions where old stands are presently uncommon. We used CANOPY, an individual-tree model calibrated with data from thinned and unthinned stands, to simulate effects of thinning on growth rates and development of old-growth structural features in second-growth northern hardwoods. Three simulated, moderately heavy thinnings over a period of 45 years nearly doubled the predicted mean radial increment of canopy trees, percent of stand basal area in large trees, and area of canopy gaps. Compared to untreated stands, thinned stands had fewer dead trees per ha, but the dead trees were larger in size and the overall volume of snags and logs was little affected. In a 77-year old even-aged stand, moderately heavy thinning was predicted to reduce the time needed to attain the minimum structural features of an old-growth forest from 79 to 36 years. Simulated treatments in an older, uneven-aged stand gave mixed results; the moderately heavy treatment stimulated individual tree growth, but the removal of some medium-sized canopy trees in conjunction with natural mortality delayed the development of old-growth structure. Total volume of dead wood may still be deficient under the thinning regimes investigated in this study, but predicted live-tree structure 45 years after moderately heavy thinning was typical of stands in the advanced transition and steady-state stages of old-growth development. Results suggest that thinning can substantially accelerate the development of old-growth structure in pole and mature northern hardwoods, but response in older, uneven-aged stands is more modest, and treatments in these stands may need to be more conservative to achieve restoration goals. 相似文献
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《Journal of Sustainable Forestry》2013,32(2-3):11-43
Abstract We discuss die human impact on the forests of northwestern Europe, especially changes in disturbance regimes and changes in the density of important features for biodiversity preservation. In southern Sweden, human impacts have decreased densities of old (>150 years) living trees and large (DBH > 40 cm) dead trees to less than 1% of their original densities. In the same fashion, forest fires have decreased enormously in extent during the last 300 years, except in southwestern Sweden where the original fire frequency was presumably lower. These changes have had a tremendous impact on forest biodiversity. The number of extinctions in Sweden increases rapidly from the north to the south both for forest living species and other species. The number of threatened species shows a similar pattern and it is probable that many of these species belong to the extinction debt, especially those species that are dependent on sun-exposed old living and dead deciduous trees. Rapid restoration measures, such as increasing the number of old sun exposed oaks and large dead deciduous trees in the vicinity of existing hot-spots, may prevent some impending extinctions. Fire is important to use when managing forests for preserving biodiversity, especially in areas where fires more recently have been suppressed and where a relict fire-adapted fauna is Still present. 相似文献
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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。 相似文献
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Experiments were conducted to elucidate how the oviposition activities ofSirex nitobei Matsumura could be affected by different conditions of the host trees, using logs from felled healthy trees and the dead
and living trees ofPinus densiflora Sieb. et Zucc. According to days elapsed after tree-felling, the proportions of oviposition defined as the proportion of
eggs laid to the potential fecundity of a female during her lifetime, could be divided arbitrarily into three groups. The
proportions of oviposition on the logs within 0–3 days after felling,i.e fresh logs, varied greatly from log to log, and about half of female adults showed proportions of oviposition under 50% (mean
±SD: 39±32%). However, all the females that oviposited on the logs 4–24 days after felling,i.e. intermediate logs, invariably showed proportions of oviposition over 50% (88±1.5%). On the other hand, proportions of oviposition
in most of the females that oviposited on the logs over 25 days after felling,i.e. old logs, were less than 50% (26±17%). The proportions of oviposition were significantly different between intermediate logs
and old logs. The mean proportion of oviposition on living trees and that for dead trees were 45 and 58%, respectively. Thus,S. nitobei in the field would exhibit its preference for weakened trees ofP. densiflora as oviposition sites, as it did for the logs 4–24 days after felling in this study. 相似文献
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研究表明 :在松材线虫病发生区 ,其病害的扩展、流行与马尾松毛虫危害有着密切的关系。当年受马尾松毛虫危害的松林 ,枯死松树数量平均为 77 879株 /hm2 ,比未受松毛虫危害的松林 (对照 ) 17 2 73株 /hm2 ,多 35 1% ;次年 ,前者平均枯死松树达 2 0 4 8株 /hm2 ,为对照 2 89株 /hm2 的 6 0 8%。松毛虫危害加速松材线虫病流行的原因是 ,松毛虫危害松树 ,削弱树势 ;弱势的松树招引松墨天牛侵入并增殖加快松树死亡 ;次年大量天牛从“松毛虫危害松木”上羽化 ,侵染健康松林 ,导致松材线虫病进一步扩散和流行。由此认为松毛虫危害是促使松材线虫病流行的重要因子 ,防治松毛虫是控制松材线虫病流行的重要环节之一 相似文献
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[目的]了解沙地樟子松天然纯林中枯立木的数量及空间结构特征,探究枯立木形成的原因,为樟子松林的保护和经营提供依据。[方法]在沙地樟子松天然纯林中设置2块1 hm~2的大样地,用全站仪对样地中所有胸径大于5 cm的立木进行定位并进行全面调查;对调查样地的基本特征,枯立木的数量特征及径级分布进行了分析,提出了用于表达林分中枯立木微环境的活立木比的概念,并采用林分空间结构参数一元分布和二元分布分析方法,对枯立木与其最近4株相邻木的关系进行分析。[结果]2块不同密度的樟子松天然纯林下更新幼苗和枯立木数量相差较大,密度较小(样地1)的样地更新幼苗和枯立木较少,而密度较大的样地(样地2)中枯立木达到200棵,林下更新幼苗数量达到15 280株·hm~(-2);樟子松天然纯林样地内枯立木主要以小径级木为主,胸径集中在11 cm以下;样地1枯立木径级连续分布,幅度较窄;样地2中的枯立木径级幅度较宽,但在20 22 cm缺刻,有2株大于23 cm的枯立木;2块样地中枯立木的分布格局均为随机分布,样地1中枯立木周围的4株相邻立木大多为活立木,且胸径较枯立木大;样地2中,只有一半的枯立木周围的最近4株立木为活立木,且有三分之一以上的枯立木胸径不是最小的,枯立木有连续分布的现象。2块样地中枯立木的角尺度-大小比数二元分布特征的差异不明显,而角尺度-活立木比二元分布特征和大小比数-活立木比二元分布特征差异明显,样地1中枯立木的最近4株随机分布于其周围的相邻木为活立木且胸径大于枯立木的比例明显高于样地2,而枯立木最近4株随机分布于其周围的相邻木有枯立木的比例明显小于样地2。[结论]樟子松天然纯林枯立木以小径级林木为主,枯立木的数量与林分密度相关,林木竞争是林木死亡的主要原因,密度过大也会产生病虫害,因此,对天然樟子松纯林要进行适度经营,保持合理密度。 相似文献
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S. Kanetani T. Kikuchi M. Akiba K. Nakamura H. Ikegame K. Tetsuka 《Forest Pathology》2011,41(5):387-391
We examined the effectiveness of a new Bursaphelenchus xylophilus detection kit, based on loop‐mediated isothermal amplification (LAMP), in old discs taken from the stem base of B. xylophilus‐infested dead trees of Pinus armandii var. amamiana (PAAm) occurring in their natural habitats. LAMP products, representing a past B. xylophilus infection, were detected in two consecutive trials from 16 of 20 discs collected from PAAm trees that died between 2003 and 2006. Bursaphelenchus xylophilus were more frequently detected using LAMP in wood samples taken from sapwood than from heartwood. No significant differences in the detection of B. xylophilus using LAMP were observed in relation to the disc collection time (from 3 to 6 years before the analysis). Bursaphelenchus xylophilus were not detected using LAMP in four discs, although a B. xylophilus infection had been confirmed for the original PAAm trees at the time they were found dead. This may have resulted from the small amount of wood chips needed for the LAMP test or the reduced number and uneven distribution of the nematode in the old dead trees. The results indicate that the new B. xylophilus detection kit will be a very efficient tool for conducting retrospective analysis of PAAm mortality factors. 相似文献
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There has been little examination of the relationship between the stocking of live trees in forests and the associated attributes of dead tree resources which could inform large-scale efforts to estimate and manage deadwood resources. The goal of this study was to examine the relationships between the stocking of standing live trees and attributes of standing dead and downed dead trees using a national inventory of forests in the United States. Results indicated that from the lowest to the highest class of live tree relative stand density, the mean biomass/ha of live trees increased over 2000% while standing dead and downed dead trees biomass/ha increased 295 and 75%, respectively. Correlations between downed deadwood biomass and stand/site attributes increased as live tree stocking increased. The size/density attributes of standing and downed deadwood exhibited no relationship with standing live stocking possibly due to the confounding factors of decay and breakage. This study proposes a conceptual deadwood stocking model with standing live tree stocking as an axis along which deadwood accretion factors (e.g., disturbance, self-thinning, and senescence) and depletion factors (e.g., decay, harvest, and stagnation) ultimately determine deadwood stocking. 相似文献