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1.
广东省榕属Ficus古树数量大、种类多,占广东古树总数的29.1%,包括榕树F. microcarpa、雅榕F. concinna等21种。通过分析榕属古树的组成和分布特征,探究影响其保存和保护的历史文化成因。结果表明,在榕属古树中,三级古树占90.2%,粤北地区一级古树数量较多;榕树数量最多,占81.8%。榕属古树在珠三角核心区和粤东、粤西两翼分布密度较大,粤北地区分布密度较小,总体呈现沿海向内陆递减的趋势;村落和寺庙宗祠是集中分布点。榕属古树的分布除了受本属生物学特征和自然地理条件约束,更受到乡村民俗文化、儒释道文化和士大夫文化等文化要素的影响。这些要素既是区域生态文化的体现,也是古树保护与利用的价值所在。传承区域生态文化是保护古树资源的重要途径。 相似文献
2.
《林业与环境科学》2021,(4)
阳春市有着丰富的古树名木资源,通过调查统计,阳春市古树名木共有1675株,隶属于35科69属96种,其中,大戟科、豆科、樟科为优势科。分析了阳春市古树名木的种类与数量、分布特征、生长及环境特征和古树群落分布特征。结果表明:从分布特征看,生长在乡村的古树为1608株,其数量是生长在城区的24倍,占建档古树名木总株数的96.00%;从生长特征可知,生长势正常的古树有1 644株,占建档古树名木总株数的98.15%,衰弱级、濒危级和死亡级古树仅占建档古树名木总株数的1.85%;从生长环境状况来看,1675株古树中生长环境好的有1615株,整体古树生长环境较好;从古树群落分布现状来看,最具代表性的古树群落为古红锥Castanopsis hystrix群落和古荔枝Litchi chinensis群落。总体而言,阳春市古树名木生长环境较好,保存得较完整,可以更好地实施下一步保护措施。 相似文献
3.
基于广东省古树名木普查,对广东省一级古树的数量、区域分布、树龄结构、树种组成、生长环境特征以及生长状况和权属等进行统计分析。结果表明,广东省有一级古树754株,隶属35科63属82种;科属以桑科、无患子科和樟科占优势,树种以榕树、雅榕、荔枝、樟和银杏为主;空间分布以粤北山区多,东西沿海少,乡村多,城区少;权属以集体为主,树龄主要集中在500~799 a范围,对过半的一级古树采取了保护和复壮措施。古树组成与分布除受自然环境约束外,还受农业种植、植物个体、风水林、宗教与宗祠、开发与迁移等文化要素以及乡土风俗、村规民约和经济价值等因素影响。提出完善古树保护管理法规,实施古树资源动态管理,建立一级古树健康监测管理系统,探索古树生态补偿机制等建议。 相似文献
4.
古树名木作为城市和风景区的核心要素,具有自然遗产和文化遗产的双重价值。在收集资料的基础上,采用实地调查和访问群众等调查方法,对珠海市高新区的古树名木资源进行逐株调查。结果表明:珠海市高新区古树数量多且种类丰富,分布范围广,在种类数和株数上有较大差异,共有古树名木1027株,隶属于33科55属69种,区内名木资源较少,多为单属单种,包括古树1023株,名木4株;98.25%的古树生长表现良好,生长衰弱的古树占总株数的1.27%,而濒危的古树仅占总株数的0.48%;古树资源的科属分布类型具有明显的热带性质和由热带向亚热带和温带过渡的特点。珠海市高新区古树群具有树种丰富多样、多集中少零散、占地面积大和生长环境参差不齐等特征,古树群的数量共有20个,总株数达876株,面积约有39.79hm^2,多以成片群状出现。 相似文献
5.
为了摸清武汉市黄陂区内古树名木的资源特征情况，采用资料查询、知情人走访、现场考察的方法，对黄陂区内古树名木的种类、数量、胸径、树龄、海拔分布等22项特征因子进行调查。结果表明：黄陂区总计拥有古树名木867株，包括26科36属40种，古树群落3处，其中：Ⅰ级古树30株，Ⅱ级古树71株，Ⅲ级古树766株；朴树最多，为269株，其次为枫香树150株，柿139株。古树名木资源的分布主要集中在木兰乡、王家河街、六指街、蔡家榨街、蔡店街、姚集街，不同区域的生长情况差别明显，祁家湾街、罗汉寺街的古树生长环境较差，不同树种海拔分布差异较大。 相似文献
6.
经调查发现:武汉市城区古树后续资源有890株,分属30科47属61种,其优势种类与城区现有的古树优势种类相近,相同树种有樟树、珊瑚朴、朴树、桂花、女贞、银杏、枫杨、榔榆、三角枫、悬铃木等10个,但其乡土树种所占的数量比例下降明显;这些古树后续资源主要集中分布在武昌区,尤其是在东湖一带,在其它城区的古树后续资源分布十分零散。武汉市城区古树后续资源的生长状况总体上生长良好,但遭受白蚁的危害较为严重,占其数量比例的15·2%,有必要开展古树后续资源的白蚁防治工作。 相似文献
7.
在对湖南省永顺县现有古树资源及其特征调查的基础上进行了综合分析和评价，结论是：现保存有古树共3408株，其中三级古树3052株，占89．6％；二级古树286株，占8．4％；一级古树70株，占2．1％；现有古树分属38科、70属、106种，其中国家级保护珍稀树种15科、18属、20种。古树中珍稀保护树种现生长较好的有黄心夜合（珍稀树种）古树32株，其中有树龄超过1000年的古树3株；珙桐古树（Ⅰ级保护植物）42株，其中有树龄在500年以上的古树1株；青钱柳古树（省级保护植物）7株，大叶榉古树（Ⅱ级保护植物）7株，青檀古树（Ⅲ级保护植物）6株；黄杉（国家Ⅱ级保护树种）古树群落2处，共有古树426株。古树资源分布广泛，且多为零星分布，少量以小片状或群落形式分布；古树主要分布在海拔300—600m的地段，其中大部分生长良好；古树资源开发利用潜力大，但保护现状不容乐观。 相似文献
8.
9.
为探究河西地区古树名木资源特征及空间分布格局,以武威市为例,采用传统统计学与GIS空间分析相结合的方法,对武威市古树名木的结构组成特征、生长状况和空间分布格局等方面进行了系统分析。结果显示：(1)武威市共有古树名木797株,裸子植物占比35.51%,被子植物占比64.49%,隶属于14科20属28种,树种以乡土树种为主,西洋梨、胡桃、圆柏、侧柏和槐为优势种,约占古树名木总量的82.69%。(2)树龄结构呈金字塔型,一、二、三级古树名木占比分别为6.65%、11.54%和81.81%,武威市古树名木后续资源丰富,但古树名木正常株仅占63.99%,生长状况欠佳。(3)古树名木呈明显的空间聚集性分布,区域上具有显著差异。分布主趋势方向为“东北—西南”,中部多、南北少,集中分布在凉州区城区及附近,历史名胜古迹及植物园等地分布较多,古浪县、民勤县和天祝藏族自治县分布较少。(4)数量和种类分布最多的地方主要位于海拔2 000 m以下、坡度小于5°或25°～35°,坡向为北坡、东南坡、东坡的地区。研究结果可为河西地区开展古树名木保护和管理工作提供基础数据和理论依据。 相似文献
10.
河源市古树资源特征分析研究 总被引：1，自引：0，他引：1
为了加强对古树的科学保护与管理，通过访谈估测法、文献追踪法、树龄与胸径回归模型估测法等方法，对河源市的古树进行研究。结果表明：1）古树数量共计 1995 株，集中在红锥 Castanopsis hystrix、榕树 Ficus microcarpa、枫香 Liquidambar formosana、木荷 Schima superba、雅榕 Ficus concinna等观赏树种以及龙眼等经济树种；2）古树树龄相对集中，主要属于三级古树，平均年龄为 195.56 a； 3）古树分布特征差异明显，主要集中在丘陵与山区县域，尤以客家乡村最为密集；4）古树健康状况总体较好，受虫害及建设扰动使部分古树出现衰弱与濒死情况；5）古树生长状况较佳（P<0.01）。研究指出，古树保护即将进入一个科技与文化并重的时代，需要做到依照古树类型、古树年龄、文化区域、健康状况、生长系数等多要素兼顾的精细化管理。 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
13.
Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and
also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the
amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter
bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K
was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed
significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed
during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly
between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species
provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient
enrichment capacity and slower decomposition rates which would minimize leaching losses.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered. 相似文献
15.
《Scandinavian Journal of Forest Research》2012,27(2):118-130
The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions. 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
17.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
18.
本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献
19.
Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional
data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral
contents and B1 and B2 vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising
germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B1 88 mg 100 g−1, B2 187 mg 100 g−1, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal
diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties
to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations. 相似文献
20.
《Wood material science & engineering》2013,8(2):76-84
Abstract Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists. 相似文献