简介：以中文Ｗｉｎｄｏｗｓ３．１为系统运行环境，以ＷＩＮＧＩＳ为基础，用ＭｉｃｒｏｓｏｆｔＶｉｓｕａｌＢａｓｉｃ４０作为开发工具，建立了荒溪分类和危险区制图模型及其信息系统．该系统由文件管理子系统、属性数据管理子系统、图形数据管理子系统、应用模型子系统等构成．应用结果验证了系统模型的各项功能，表明系统设计合理，运行稳定、安全．

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简介：为木质的植物差异，结构和新生上的读经台州的福雷斯特里的这研究，70空铅，每25?在25的m?m，用一种系统的随机的采样技术和100的间隔被选择?沿着一根横断线的m。为估计幼苗和树苗，二2??楷桴？

简介：Background:Tropicaldryforestscoverlessthan13%oftheworld'stropicalforestsandtheirareaandbiodiversityaredeclining.InsouthernAfrica,themajorthreatisincreasingpopulationpressure,whiledroughtcausedbyclimatechangeisapotentialthreatinthedriertransitionzonestoshrubland.Monitoringclimatechangeimpactsinthesetransitionzonesisdifficultasthereisinadequateinformationonforestcompositiontoallowdisentanglementfromotherenvironmentaldrivers.Methods:Thisstudycombinedhistoricalandmodernforestinventoriescoveringanareaof21,000km~2inatransitionzoneinNamibiaandAngolatodistinguishlatesuccessiontreecommunities,tounderstandtheirdependenceonsitefactors,andtodetecttrendsintheforestcompositionoverthelast40years.Results:Thewoodlandsweredominatedbysixtreespeciesthatrepresented84%ofthetotalbasalareaandcanbereferredtoasBaikiaea-Pterocarpuswoodlands.Aboostedregressiontreeanalysisrevealedthatlatesuccessiontreecommunitiesareprimarilydeterminedbyclimateandtopography.TheSchinziophytonrautaneniiandBaikiaeaplurijugacommunitiesarecommononslightlyinclinedduneorvalleyslopesandhadthehighestbasalarea(5.5-6.2m~2ha~(-1)).TheBurkeaafricana-GuibourtiacoleospermaandPterocarpusangolensis-Dialiumenglerianumcommunitiesaretypicalforthesandyplateauxandhaveahigherproportionofsmallerstemscausedbyahigherfirefrequency.AdecreaseinoverallbasalareaoratrendofincreasingdominationbythemoredroughtandcoldresilientB.africanacommunitywasnotconfirmedbythehistoricaldata,butthereweresignificantdecreasesinbasalareaforOchnapulchraandthevaluablefruittreeD.englerianum.Conclusions:Theslopecommunitiesaremoreshelteredfromfire,frostanddroughtbutaremoresusceptibletohumanexpansion.ThecommunitywiththeimportanttimbertreeP.angolensiscanbestwithstandhighfirefrequencybutshowssignsofahighervulnerabilitytoclimatechange.Conse