共查询到19条相似文献，搜索用时 359 毫秒
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对京昆高速公路河北段服务区绿化模式及植物应用进行了研究。根据植物应用现状提出了3类模式:(1)广场休闲绿地型:此模式以井陉服务区为代表,用于车、人停留活动较多的服务区。(2)庭院绿地型:以涿州、定兴、顺平、曲阳、行唐、石家庄服务区为代表,园林绿化充分体现庭院休闲性质。(3)农业生态观光园绿地型:以唐县为模式,适合满城、灵寿,绿化充分结合当地农业特色。同时对京昆路段服务区绿化应用的树种进行综合评价,评出一类树种27种;二类树种20种;三类树种34种;四类树种14种。针对绿化提升改造进行了树种规划,确定了不同绿化模式的基调树种、骨干树种、一般树种、1a生植物、宿根花卉、蔬菜及农作物种类,为提升改造和其相类似地区其它高速公路服务区树种选择提供了依据。 相似文献
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以广东省惠州市惠阳区境内的生态景观林带作为研究对象,调查4个树种配置模式下的树木早期生长表现,并依据实地调查的立地条件,利用相关模型制作软件对4个不同树种配置模式下预期景观效果进行模拟。研究结果表明,惠阳区生态景观林带4个树种配置模式下的树木成活率均值为84.25%,树高、胸径和冠幅的均值分别为3.27 m、5.36 cm和1.64 m,早期生长情况较好。综合评价结果表明,4种树种配置模式中,树木早期生长综合表现较好的为模式GC1(夹竹桃、红花羊蹄甲、香樟、黄花风铃木等树种随机混交);惠阳区生态景观林带调查的9个树种树木早期生长综合表现排名靠前的为红花羊蹄甲、香樟树和美丽异木棉。总体而言,不同生态景观林带树种配置模式树木生长表现有所不同,并会产生不同的景观效果;同时,立地条件、树种选择和配置模式均会对生态景观林带公路景观效果产生明显影响。 相似文献
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用样方法,研究了小陇山林区5种典型灌木林地改造模式的乔木树种天然更新幼苗的密度和多样性。结果表明:5种灌木林地改造模式的乔木树种天然更新情况总体良好,小于50 cm高度级幼苗数量相对较少,大于50 cm高度级幼苗的存活率较高;5种改造模式天然更新树种以锐齿栎为主,其中,全面割灌改造日本落叶松(模式3)更新幼苗物种丰富度最高,全面割灌改造油松模式(模式2)天然更新树种丰富度最小;带状割灌改造模式(模式4和模式5)和全面割灌改造华山松模式(模式1)的更新树种多样性较高,各树种分配均匀,优势树种的集中性较低;改造树种华山松的天然更新能力较油松日本落叶松强,带状割灌改造模式更有利于华山松天然更新。 相似文献
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金叶榆是我国自主培育成功的彩叶植物新品种。为丰富高寒半干旱区生态城市建设树种资源,改变园林景观色彩单一、植物配置模式单调的局面,进一步提升城乡绿化景观的内涵层次,从宁夏林业科学研究所引进金叶榆,进行了区域栽培试验及示范推广,结果表明:该树种在高寒半干旱地区生长表现优良,抗寒耐旱,种苗繁殖容易,园林用途广泛,成活率在98%以上,景观效果极佳,是优良的黄色系彩叶树种;提出了该树种在城镇园林绿化中的5种配置模式,即模纹花坛配置模式、色篱配置模式、散植模式、列植模式、片植配置模式,以期增加高寒半干旱区彩叶树种资源,丰富园林景观色彩,为园林绿化建设带来更广阔的发展空间。 相似文献
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Érica Hasui Vinícius X. Silva Rogério G. T. Cunha Flavio N. Ramos Milton C. Ribeiro Mario Sacramento Marco T. P. Coelho Diego G. S. Pereira Bruno R. Ribeiro 《林业研究》2017,28(5):963-974
Species distribution models are used to aid our understanding of the processes driving the spatial patterns of species’ habitats. This approach has received criticism, however, largely because it neglects landscape metrics. We examined the relative impacts of landscape predictors on the accuracy of habitat models by constructing distribution models at regional scales incorporating environmental variables (climate, topography, vegetation, and soil types) and secondary species occurrence data, and using them to predict the occurrence of 36 species in 15 forest fragments where we conducted rapid surveys. We then selected six landscape predictors at the landscape scale and ran general linear models of species presence/absence with either a single scale predictor (the probabilities of occurrence of the distribution models or landscape variables) or multiple scale predictors (distribution models + one landscape variable). Our results indicated that distribution models alone had poor predictive abilities but were improved when landscape predictors were added; the species responses were not, however, similar to the multiple scale predictors. Our study thus highlights the importance of considering landscape metrics to generate more accurate habitat suitability models. 相似文献
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《Forest Ecology and Management》1997,97(1):25-37
Single tree volume estimation models are produced for four Julbernardia-Brachystegia woodlands in Malawi. The estimation models are based on the regression of volume on one or a number of independent variables derived from diameter and height. In total, 1282 trees from 46 species were felled and individually measured. Site-specific models were produced for the dominant species and important species groups, with separate models for canopy and under-storey species groups from three sites. Compared to diameter, height was a poor predictor of volume and only derivations of diameter were used wherever possible. The models may have wider applicability, particularly in woodlands with similar structure, climatic and edaphic conditions, but should be validated since their applicability outside of the four sample sites has not yet been tested. 相似文献
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Many boreal tree stands are neither clearly even-aged nor clearly uneven-aged. The stands may undergo a series of stages, during which an even-aged stand is transformed into two-storied mixed stand, and finally to multistoried or uneven-aged stand structure. The species composition often changes during the succession of stand stages. This study developed models for stand dynamics that can be used in different stand structures and species compositions. The model set consists of species-specific individual-tree diameter increment and survival models, and models for ingrowth. Separate models were developed for Scots pine, Norway spruce, and hardwood species. The models were used in a growth simulator, to give illustrative examples on species influences and stand dynamics. Methods to simulate residual variation around diameter increment and ingrowth models are also presented. The results suggest that mixed stands are more productive than one-species stands. Spruce in particular benefits from an admixture of other species. Mixed species improve diameter increment, decrease mortality, and increase ingrowth. Pine is a more beneficial admixture than birch. Simulations showed that uneven-aged management of spruce forests is sustainable and productive, and even-aged conifer stands growing on medium sites can be converted into uneven-aged mixed stands by a series of strong high thinnings. 相似文献
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海南岛尖峰岭树木园主要构筑类型热带树木名录 总被引：3，自引：0，他引：3
热带树木的构筑型是热带树木的遗传结构与热带环境因子长期相互作用的外在表现 ,它是热带生物结构多样性非常具体而直观的表达。热带林丰富多彩的形态和外貌特征 ,是组成热带林多种多样的树木的排列组合的整体表征。热带森林的外貌和总体特征是由每个树木的形态特征和整体结构所决定的。因此 ,研究热带树木的构筑型 ,对于认识热带森林的多样性组成和总体结构 ,阐明热带森林生态系统结构与功能的关系 ,合理保护和充分利用热带林生物多样性资源 ,都具有非常重要的意义。关于构筑型的研究历史及其进展 ,我们已作过综述 (臧润国等 ,1 998) ,国外… 相似文献
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云南松、华山松、川滇桤木、圆柏、蓝桉等5个树种在昆明寻甸羊街相同立地条件下生长适应性研究结果表明,各树种间生长均存在极显著差异,川滇桤木造林成活率和生长量明显优于其它4个树种,具有较强适应能力,其树高、地径、冠幅等3个生长性状具有较高的一致性,并超过了兰桉、云南松、华山松的各项指标低于川滇桤木,但其地径、冠幅生长性状均高于兰桉,表现出了良好适应性.运用非线性回归分析,建立5个树种的树高和地径的曲线模型,模型拟合性好,相关指数的平方(R2)均在0.98以上,反映出5个树种4 a生的生长规律,为当地造林树种的筛选提供依据和参考. 相似文献
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《Southern Forests》2013,75(4):221-237
The relationship between tree height (h) and tree diameter at breast height (dbh) is an important element describing forest stands. In addition, h often is a required variable in volume and biomass models. Measurements of h are, however, more time consuming compared to those of dbh, and visual obstructions, rounded crown forms, leaning trees and terrain slopes represent additional error sources for h measurements. The aim of this study was therefore to develop h–dbh relationship models for natural tropical forest in Tanzania. Both general forest type specific models and models for tree species groups were developed. A comprehensive data set with 2 623 trees from 410 different tree species collected from a total of 1 191 plots and 38 sites covering the four main forest types of miombo woodland, acacia savanna, montane forest and lowland forests was applied. Tree species groups were constructed by using a k-means clustering procedure based on the h–dbh allometry, and a number of different non-linear model forms were tested. When considering the complexity of natural tropical forests in general and in particular variations of h–dbh relationships due to high species diversity in such forests, the model fit and performance were considered to be appropriate. Results also indicate that tree species group models perform better than forest type models. Despite the fact that the residual errors level associated with the models were relatively high, the models are still considered to be applicable for large parts of Tanzanian forests with an appropriate level of reliability. 相似文献
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木材干燥基准数学模型的研究与应用 总被引：2，自引：0，他引：2
阐述在木材干燥计算机控制系统中使用干燥基准数学模型的方法，并介绍了如何正切利用相应软件回归干燥基准和建立干燥基准模型，文中列出了各种回归出的模型的图表以及五种常用木材的干燥基准模型。本方法已成功地应用在国家“八五”攻关项目“木废料能源联合干燥技术研究”的计算机控制系统中。 相似文献
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Basal area growth models for individual trees of Norway spruce, Scots pine, birch and other broadleaves in Norway 总被引：1，自引：0，他引：1
Distance-independent individual tree growth models based on about 30,000 observations from the National Forest Inventory and the Norwegian Forest Research Institute have been developed for the main tree species in Norway. The models predict 5-year basal area increment over bark for trees larger than 5 cm at breast height. Potential input variables were of four types: size of the tree, competition indices, site conditions, and stand variables including species, mixtures and layers. The squared correlation coefficient (R2) varied from 0.26 to 0.55. The accuracy of the models was tested by comparing the individual tree models with Norwegian diameter increment models. The accuracy is similar, but individual tree models forecast diameter distributions directly. The inclusion of species mixture and layer as variables increases the reliability of the models in mixed and in uneven-aged stands. 相似文献
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In order to study 5 cultivation models such as arbor-shrub, arbor-shrub-herb and their disposition for vegetation recovery, 10 arbor species, 7 shrub species and 5 herb species suitalde for locat sites were choiced at waste heap platform of Fushun Coal Mine. The experiment adopted the randomized block design, three replicates, with 0.067hm^2 at each thinned plot. The experiment results of 2-year vegetation recovery showed that the survival rate of woody plants was significantly different among species and there existed significant differences in ground diameter and height increments. The results of the initial stage of the experiment showed that the disposition of A and C were the optimal cultivation models, and Robinia pesudoacacia, Hippophae rhamnoides, Amorpha fruticosa, Caragana chamlagu,Ulmus pumila were the best tree species for arbor-shrub-herb disposition. 相似文献