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基于城市森林功能分类和斑块等级的思想框架,对高空间分辨率航片数据进行解译,以广州市中心区作为研究区,对其树冠覆盖景观进行分析。结果表明:1)研究区树冠覆盖率为19.5%,其中天河区最高达26.5%,芳村区最低仅6.6%。生态公益林在5个类型组(生态公益林、公共园林、居所林、生产林和防护林)的树冠覆盖斑块中面积最大,占55.4%,其次为生产林,占19.9%。各类型的平均面积以生态片林最大,行道树最小。2)树冠覆盖斑块以面积大于1hm2的特大型为主,占总斑块面积的78.8%,小斑块(<0.1hm2)、中斑块(0.1～0.5hm2)和大斑块(0.5～1hm2)分别占9.2%,7.9%和4.2%。生态片林在特大型斑块中所占比例最大,其次为生产林,其他面积等级斑块均以居所林所占比例最大。3)特大斑块主要位于中心区北部的白云山和城市发展东部拓展区的天河、黄埔的丘岗林地区域,以及海珠区南部,而荔湾区、越秀区和东山区均以小斑块数量占优。面积在0.5～1hm2的斑块多分布于特大型斑块周边,主要是由人为干扰引起的破碎化表现。树冠连续覆盖是实现生态过程与格局连续性的有效途径,行道树类型斑块数量最大,相对破碎,但最具形成连续覆盖的潜... 相似文献
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马鞍山城市森林景观镶嵌与其城郊分布梯度格局研究 总被引：1，自引：0，他引：1
运用景观生态学的原理与方法及3S技术,研究马鞍山市区63.8 km2城市森林景观特点及与其他景观的关系;并沿城市南北纵轴设立样带,采用移动窗口法对6个样区景观要素的景观特征进行计算,分析城市森林斑块在城市中心与城郊间的分布规律.结果表明:该城市的景观要素有各类硬质铺装表面、城市森林、农业用地、水面与一般绿地五大类,分别占67.25%、16.47%、11.9%、3.99%、0.39%;景观多样性指数1.071 28;主要景观要素的优势度排列顺序为硬质表面0.573,城市森林0.472,农田0.122,水面0.114,一般绿地0.029,城市森林已具有较高的环境控制能力.城市森林类型有风景林、庭院林、游憩林、道路林、苗圃及防护林;分别占城市森林面积的40.8%、23.9%、21.5%、7%、3.6%、3.2%;风景林面积最大,斑块数量最少;庭院林斑块数量最多,道路的绿化质量较高.城市森林斑块数达到2 464,最大面积185.1 hm2,平均面积0.43 hm2,大面积的风景林地主要集中在城市西侧;城市森林的景观密度及最小距离指数都反映其具有一定程度聚集分布的特征;而农田在城南与城北近郊具有较高的聚集性;城市森林在城市南北轴向的分布具有明显的变化,其面积比、斑块密度等城区高于近郊;城市北侧的城市森林要优于城市南侧. 相似文献
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塞罕坝国家级森林公园风景游憩林类型与特征研究 总被引：1，自引：0，他引：1
本研究基于多尺度、多因素植被类型分类法探讨了塞罕坝国家级森林公园风景游憩林资源的类型划分,通过典型风景游憩林林分样地调查、季相景观照片的获取、解析与视觉设计,对不同类型风景游憩林林分及景观特征进行了系统分析,得出以下结论和建议:(1)塞罕坝国家级森林公园风景游憩林资源丰富、类型多样,可从林分和景观两个尺度进行分类。(2)森林公园不同类型风景游憩林林分,其林相及林内景观特征各异。(3)塞罕坝森林公园处于森林和草原、山丘与高原的交接带,地理位置优势明显,景观类型丰富多样。(4)建议保护天然次生林景观,同时通过栽植乡土阔叶树种,合理营造针阔混交色彩层次丰富的风景游憩林。(5)对于大尺度的森林景观的人工采伐痕迹,应从视域角度予以调整,通过调节视域范围,适当遮挡屏蔽不良景观、展现优美景观。 相似文献
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湖南省林科院试验林场森林植被景观格局及破碎化分析 总被引：4，自引：0，他引：4
用1∶5500森林类型图为信息源,以ViewGIS软件为手段,对湖南省林科院试验林场森林植被景观类型斑块的大小、形状、空间特征以及破碎化程度进行了分析.结果表明：林场的森林景观分为15种森林类型,总面积约为3529841.093m2,共有斑块数90个,森林斑块平均面积较小,且以马尾松人工林、樟树人工林、次生常绿阔叶林等为优势类型;各森林景观类型的形状指数较小,说明各森林景观类型的形状偏向于圆形或正方形,其斑块的边界率都较低;不同森林景观类型分维数变化较小,整个林场森林景观斑块数破碎化指数为0.0322,其中樟树人工林、次生常绿阔叶林、马尾松人工林、油茶林的破碎化指数较大. 相似文献
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《林业资源管理》2013,(3):101-105
以冀北山区木兰林管局北沟林场的森林景观为研究对象,在森林景观分类的基础上,计算了森林景观斑块面积、斑块周长、分形维数、景观多样性等特征参数。结果表明:研究区森林景观类型为8类,共235个斑块,斑块总面积为1 634.12hm2,景观斑块分形维数人工华北落叶松林最大(1.990 3),人工针叶混交林最小(1.115 9);景观多样性指数人工针叶混交林最大(8.662 8),天然针叶混交林最小(2.143 2);景观优势度指数天然油松林最大,为0.646 7,人工华北落叶松林最小,为0.108 3;景观均匀度指数人工针叶混交林最大,为0.961 7,天然针叶混交林最小,为0.531 2;斑块密度天然阔叶混交林景观类型最大(0.312 5),天然柞树林最小(0.118 3)。研究结果可以为景观尺度的森林健康近自然经营提供数据支撑。 相似文献
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根据土地类型和植被特征划分景观类型,然后运用GIS软件进行数字化,并计算斑块指标。分析结果表明:南湾国家级森林公园森林景观共有松林、杉林、栎林、竹林、板栗林和茶园等6种类型。各类型的面积、周长及斑块数都不均衡;松、杉林景观处于主导地位;茶园形状最复杂,而松、杉林景观破碎化程度最高,受人为因素影响最大。 相似文献
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《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
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《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
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《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
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《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
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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
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《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
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《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
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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
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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