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1.
基于Pleiades-1卫星数据薇甘菊信息提取 总被引：1，自引：0，他引：1
薇甘菊Mikania micrantha是一种极具危险性的外来物种,对侵入地生态系统的完整性构成了极大威胁,及时、准确掌握薇甘菊分布信息成为防控其入侵的关键技术。目前,薇甘菊的监测主要采用人工方法,耗时费力。随着遥感技术的发展,采用高分辨率遥感数据快速准确提取薇甘菊分布信息成为可能。以深圳市Pleiades-1影像为主要信息源,开展薇甘菊信息的快速提取研究。结果表明:(1)Pleiades-1影像分辨率较高,在开展薇甘菊识别时的最佳波段组合是R(B3)、G(B2+B4)/2、B(B1);(2)通过Brovey变换、Gram-Schmidt变换、Pansharpen变换的对比分析,Gram-Schmidt变换在信息量、最佳波段、清晰度等方面,均优于Brovey变换和Pansharpen变换,既保留了大量的原有信息,又增强目视解译效果,是影像融合时的最优变换;(3)基于光谱与纹理信息分析,提取薇甘菊信息范围更好;(4)薇甘菊信息提取的最佳分割尺度是30,综合识别精度达95.3%,说明采用高分辨率遥感影像能实现薇甘菊信息的精细识别。 相似文献
2.
采用Worldview-2八波段影像作为数据源,选取东洞庭湖湿地核心区域作为研究区,进行了Worldview-2八波段特征分析、构建改进遥感指数、采用改进遥感指数阈值分层分类的策略对湿地区域进行信息提取。研究结果表明,基于Worldview-2八波段影像改进指数的湿地类型分类总精度达到了92.24%,Kappa系数为0.902,比原始遥感指数的分类精度提高了8.18%,特别是对草滩地和泥滩地的区分有了较大的提高,是有效、准确提取湿地类型的技术方法。 相似文献
3.
分析遥感影像不同类型波段在树种分类中的表现,可为遥感数据光谱信息的深度挖掘提供基础信息。本研究以8波段Worldview-2影像为数据源,将光谱波段分为传统波段和新增波段两种类型,在室外调查的基础上利用最大似然法对树种进行分类,分析传统波段、新增波段及完整波段在树种识别中的精度差异。结果表明:传统波段对树种分类的总体精度(63.348 2%)不及新增波段的(67.669 6%)高,完整波段分类的总体精度最高(74.071 3%)。本研究表明,在树种识别中,Worldview-2新增波段比传统波段更具优势,两类波段的充分结合,更有利于树种的识别。 相似文献
4.
基于ETM+影像竹林信息提取的最佳波段组合研究 总被引：2，自引：0，他引：2
以竹林信息提取为研究目的,应用最佳指数法(OIF)法和典型地物影像光谱特征曲线分析,对福建省顺昌县ETM+多光谱数据的波段选组合进行了研究.研究结果表明:345波段是竹林信息提取的最佳波段组合;典型地物影像光谱特征曲线可以直观的看出地物在不同波段上的光谱差异,能为最佳波段选择提供可靠的参考依据;竹林在第5波段与其他地物光谱差异最大,分离效果最好,在第1波段的光谱影像特征曲线与阔叶林相近,在第2波段与针叶林相近,说明在第1波段和第2波段中竹林分别与阔叶林、针叶林容易混淆,不利于竹林信息提取. 相似文献
5.
2021年，在浙江省温州市瓯海区发现假泽兰属Mikania Willd.薇甘菊Mikania micrantha Kunth野外种群，此发现为浙江省菊科Asteraceae归化新记录属、种。在给出该植物的形态特征、实地拍摄图片和凭证标本（温州大学标本馆-WZU）的基础上，对薇甘菊在温州地区野外入侵现状和其生境植物多样性进行调查。结果表明，薇甘菊在湿地水岸边和山地路边均有较强的适应性，已形成了初步扩散的趋势。提出了加强生物检疫，外来入侵植物的巡查，做到早发现早清除的防控建议。本次发现为我国外来入侵植物的防控、生物多样性和生态环境的保护提供了重要信息，并且薇甘菊在浙江的发现更新了其在我国入侵分布的记录，浙江成为该种入侵分布的中国最北界。 相似文献
6.
《中南林业科技大学学报(自然科学版)》2015,(11)
以我国自主发射的第一颗高分辨率卫星(GF-1卫星)的影像为数据源,在东洞庭湖开展湿地信息提取。结合国家湿地遥感分类系统和高分影像数据的可解译性,建立了东洞庭湖湿地类型遥感分类系统,包括湖泊、河流、泥滩地、林地、芦苇、苔草、辣蓼+泥蒿7种湿地类型。利用最佳指数和联合熵2个指标确定最佳波段组合方式为4(R)3(G)2(B),并在遥感图像进行预处理的基础上,采用面向对象的决策树进行分类,结果表明:基于面向对象决策树遥感分类方法比最大似然法分类的精度高,总分类精度达85.41%,Kappa系数为0.822 5,并且各类信息的提取精度均有所提高,其中湖泊、芦苇、林地的精度较高。 相似文献
7.
8.
《中南林业科技大学学报(自然科学版)》2016,(10)
GF-1,ZY-3和ZY1 02C三种国产卫星数据为研究对象,在分析单波段信息熵的基础上,运用联合熵,最佳指数和相关系数矩阵确定3种影像数据的最佳波段组合,选择具代表性的PC、Brovey、GS、IHS和MT变换融合等五种基于像素的融合方法对影像进行融合,分析融合前后影像联合熵以及融合后各影像波段的梯度变化。研究结果表明:(1)GF-1的最佳组合为Band1、Band3及Band4,ZY-3的最佳组合为Band2、Band3及Band4,ZY-1 02C数据的最佳波段组合为Band1、Band2及Band3;(2)融合后影像中Brovey变换融合的联合熵小于融合前,其余4种融合方法联合熵均大于融合前联合熵值;(3)GF-1、ZY-3和ZY 1 02C影像数据最佳融合方法分别为GS融合、PC融合以及IHS变换融合。 相似文献
9.
为掌握云南薇甘菊危害核心区内薇甘菊发生危害的分布特征,2010年11月22日沿滇缅公路木康至畹町桥段路肩两侧200m进行薇甘菊发生危害情况调查。结果表明,滇缅公路薇甘菊分布不连续,呈板块、点状分布;纬度越低,距中缅边境越近,薇甘菊发生、分布点频度越高;薇甘菊发生点盖度变化大,厚薄不均,发生面积大小不等;危害植物高度由被侵害植物高度决定;覆盖能力强,危害植物种类多,表现极强的入侵、侵害性;薇甘菊分布点多在农业耕作区的田边、地角以及稀疏林地、河流、溪水、水沟边和农户院落四旁;林木郁闭度大的林地薇甘菊危害相对较轻,完全郁闭的林中尚未发生薇甘菊危害。 相似文献
10.
基于语义相关的面向对象林地信息提取 总被引：1，自引：0，他引：1
基于地物间的语义相关关系,结合面向对象的影像分析技术,提出了适用于高分辨率影像的林地信息提取方法,包括影像分割和林地信息提取2大步骤;并以福州市2003年6月成像的IKONOS卫星影像数据为例进行了林地信息提取实验。结果表明:①通过模糊和最近邻2种分类技术分别完成植被、林地信息的提取,提高了提取过程的合理性;②以面向对象的方式进行信息提取,不仅能避免细节信息的干扰,还能利用影像的纹理信息,这相当于对影像数据进行了优化,提取结果的精度和完整性均得到了提高。 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.
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
16.
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
17.
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
18.
《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
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