共查询到20条相似文献，搜索用时 78 毫秒
1.
平江幕阜山黄山松群落特征及其演替规律的探讨 总被引：1，自引：0，他引：1
湖南平江幕阜山海拔950m以上山地分布着大片的黄山松林，是当地主要的森林群落类型。通过对不同海拔、坡度、坡向的黄山松群落样地调查，统计出群落灌木层和草本层的重要值；绘制出黄山松种群胸径-株数关系图和树高-株数关系图。研究结果表明，群落中约有种子植物40科，66属，70种；群落的乔木层为纯林，灌木层树种的海拔分布差异明显，和草本层一起多数为耐荫植物；群落正向着稳定群落的方向发展，最后随着落叶阔叶树的发展，将会被落叶阔叶林取代。其演替规律为：裸地或瘠薄空旷地→黄山松林→黄山松 落叶阔叶树混交林→落叶阔叶林→常绿阔叶林。 相似文献
2.
在对天宝岩国家级自然保护区不同海拔天然猴头杜鹃林乔木种群全面调查基础上,对猴头杜鹃林进行立木分级,采用动态可比性林木分级法研究了猴头杜鹃林种群结构。研究结果表明：不同海拔天然猴头杜鹃林均以Ⅳ级木占绝对优势,该级林木株数远远大于其他级林木数量。此外,各海拔天然猴头杜鹃林Ⅳ级木数量呈现高〉低〉中,而其在相应海拔所占比例却与海拔呈正相关;低海拔天然猴头杜鹃种群处在A型种群的前中期,中海拔种群处在A型种群的后期,高海拔天然猴头杜鹃种群则处在A型种群的中后期。 相似文献
3.
基于浙江景宁草鱼塘亚热带针阔混交林动态监测样地(1 hm2)群落的调查数据,采用点格局分析方法等,以径级替代年龄层次,研究样地内优势树种黄山松与马褂木不同年龄段在样地的分布情况和空间关联性.结果显示:(1)黄山松和马褂木种群的径级分布均呈反"J"型.(2)样地中整个黄山松种群主要呈聚集分布,且聚集程度随着种群年龄的增加,表现出相应的减弱趋势.黄山松种群中树、小树在大尺度上显现出随机分布;样地中不同年龄段的马褂木种群均表现出随机分布的趋势.(3)小尺度上,黄山松种群大树对小树、大树对中树出现显著的空间负相关;小尺度上,马褂木种群中树对小树、大树对小树表现为空间正相关.(4)黄山松各径级个体在小尺度上均对马褂木个体呈显著负相关,随着尺度的增加,转变成无显著相关性.小尺度上,马褂木种群中树对黄山松种群小树、中树表现为空间负相关,马褂木大树对黄山松种群中树和大树在任何尺度上表现为无显著相关性.发现针阔混交林优势树种通过密度制约、化感作用和生态适应性对策来形成特定的空间分布格局,实现物种间的共存和竞争作用. 相似文献
4.
对黄山松地理种源种子播种品质和育苗试验的研究表明,种源间种子千粒重、室内发芽率、苗圃出苗率均存在显著差异。种源的经度、纬度与千粒重相关不紧密,海拔高与苗高生长量呈较紧密的负相关。各地理种源苗木生长量差异极显著,同一种源不同年份苗木生长量也有差异。浙江省的磐安、东阳、庆源、天台等种源苗期生长较好。 相似文献
5.
6.
7.
安徽黄山黄山松的初步观察 总被引：2，自引：0，他引：2
黄山松的形态黄山松是常绿乔木,高达30米,胸径达80厘米;在无风处树干端直;在郁闭林分内,立木干形通直少枝,干形良好,壮龄木树冠塔形,老树顶部平展。在悬崖峯脊,则因强风吹袭,常偏斜或平截。所谓:“绝巘危崖,尽皆怪松悬结,高者不盈丈,低仅数寸,平顶短鬣,盘根虬干,愈短愈老,愈老愈奇。”树皮暗棕色,鳞片状剥离。枝刚直,斜出。针叶二枚一束,硬直散立,长度则随立地条件有很大差异;在海拔高的峯顶,受风吹袭处,针叶短而密,长度仅4厘米;在海拔低的避风处则长达15厘米。球果长卵形到卵形,外侧稍稍突出,果鳞开裂后球果呈圆锥状卵形,长及径均为4—6厘米;果柄短,长成时向下扭转,可在树上保存2—4年,10月中下旬成熟,成熟后鳞片开裂,种子飞散。种子椭圆形或长圆形,端 相似文献
8.
《浙江林业科技》2019,(5)
森林优势树种对群落环境和结构形成具有重要的作用。文章分析了浙江省景宁县荒田湖林场针阔混交林3个50 m×50 m样地中黄山松Pinus taiwanensis和木荷Schima superba种群的径级结构与空间分布格局。结果表明,黄山松种群在3个样地中的径级结构均呈正态分布,而木荷种群的小径级个体相对较多;黄山松和木荷幼树以及大树在空间分布上具有隔离现象,木荷种群幼树阶段在小尺度上均为聚集性分布,在较大尺度上呈现随机分布的格局,而黄山松的幼树和大树的空间分布格局在不同样地间存在差异。本研究结果表明两个树种在生活史不同阶段的生态需求存在差异,进而引起空间分布格局的差异,在制定森林经营措施时应考虑优势种的径级结构及其空间分布情况。 相似文献
9.
10.
福建牛姆林自然保护区观光木群落特征的初步研究 总被引：5，自引：1，他引：5
通过野外调查和统计生态学原理统计分析,对牛姆林自然保护区观光木群落的物种组成、群落结构和物种多样性等特征进行初步研究,结果表明:该群落属常绿阔叶混交林,物种组成丰富,分层现象明显,结构复杂,生境资源利用率和物种多样性水平都较高;种群内观光木年龄结构总体趋于稳定,但Ⅰ级苗木较少,同时观光木开花结实受环境影响大,在演替过程中会出现“青黄不接”现象,易被淘汰,因此开展保护该种群工作具有紧迫性。 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.
《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
14.
《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
15.
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
16.
《Scandinavian Journal of Forest Research》2012,27(2):131-138
The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided. 相似文献
17.
18.
《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 相似文献
19.
Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic
or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts
(stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea
(Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content
as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest
N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized
to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea,
largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for
N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant
components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N
released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures
were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality
components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in
the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols.
Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest
age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its
components are mixed. 相似文献
20.
A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste
disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization,
(2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two
pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea
(Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect
on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage
sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but
affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献