简介:研究了不同面积规模的全面皆伐(2.0hm2和3.33hm2)、带状皆伐(带长均为60m,带宽分别为3m、6m和9m)和块状皆伐(25m2、100m2和400m2)对毛竹林更新生长的影响。结果显示:3种皆伐方式对竹林更新生长影响不同,其中全面皆伐后的竹林长势较差,生物量较低,且皆伐面积越大,竹林更新生长越差;带状皆伐,皆伐带宽为3m和6m的竹林更新生长状况均较好,以带宽为6m时综合效果最好;在块状皆伐中,皆伐面积为25m2的竹林更新生长最好。此外,皆伐后对毛竹伐桩进行施肥,能够促进竹林的恢复生长;竹林的坡向也影响林分的更新生长,阴坡林分通常在皆伐后2年即能恢复到皆伐前状态,而阳坡林分的恢复则需要3年以上。
简介:棕榈藤作为热带、亚热带植物中重要的森林资源,优质的藤材是重要的加工利用材料,具有重要的经济价值。叶片光合能力对藤材的形成具有重要影响,利用叶绿素荧光仪测定黄藤(Daemonoropsjenkinsiana)、大白藤(Calamusfaberii)、小白藤(C.balansaeanus)的叶绿素荧光参数,为研究逆境条件下棕榈藤的光合能力和选择适宜的栽培条件提供参考。结果表明,在实验室条件下3种棕榈藤的光系统Ⅰ(PSⅠ)实际光量子效率Y(Ⅰ)为小白藤〉大白藤〉黄藤,光系统Ⅱ(PSⅡ)的Y(Ⅱ)为大白藤〉黄藤〉小白藤;非光化学猝灭系数qN由高到低依次为大白藤、黄藤和小白藤;而光化学猝灭系数q_P则是小白藤最高,黄藤次之,大白藤最低;PSⅠ的电子传递效率ETR(Ⅰ)是小白藤〉大白藤〉黄藤,而PSⅡ的ETR(Ⅱ)值则是小白藤〉黄藤〉大白藤;PSⅡ最大光量子产量F_v/F_m维持在0.78~0.8范围内,且大白藤显著高于黄藤和小白藤(P〈0.05)。由此可见,在实验室条件下小白藤的光合效率在这3种藤中最高,其次为黄藤,大白藤最低;且光保护能力为大白藤最高,黄藤次之,小白藤最低。
简介:Background:Monitoringforesthealthandbiomassforchangesovertimeintheglobalenvironmentrequirestheprovisionofcontinuoussatelliteimages.However,opticalimagesoflandsurfacesaregenerallycontaminatedwhencloudsarepresentorrainoccurs.Methods:Toestimatetheactualreflectanceoflandsurfacesmaskedbycloudsandpotentialrain,3DsimulationsbytheRAPIDradiativetransfermodelwereproposedandconductedonaforestfarmdominatedbybirchandlarchinGenheCity,DaXing’AnLingMountaininInnerMongolia,China.Thecanopyheightmodel(CHM)fromlidardatawereusedtoextractindividualtreestructures(location,height,crownwidth).Fieldmeasurementsrelatedtreeheighttodiameterofbreastheight(DBH),lowestbranchheightandleafareaindex(LAI).SeriesofLandsatimageswereusedtoclassifytreespeciesandlandcover.MODISLAIproductswereusedtoestimatetheLAIofindividualtrees.CombiningalltheseinputvariablestodriveRAPID,high-resolutionopticalremotesensingimagesweresimulatedandvalidatedwithavailablesatelliteimages.Results:Evaluationsonspatialtexture,spectralvaluesanddirectionalreflectancewereconductedtoshowcomparableresults.Conclusions:Thestudyprovidesaproof-of-conceptapproachtolinklidarandMODISdataintheparameterizationofRAPIDmodelsforhightemporalandspatialresolutionsofimagereconstructioninforestdominatedareas.
简介:TheapplicationofGeographicInformationSystem(GIS),RemoteSensing(RS)andGlobalPositionSystem(GPS)intheresearchofforestlandscapeisoutlinedinthispaper.Theintegrationofthe3Stechniqueisalsodescribed.Inthe3Ssystem,RSisusedtoobtainthevariousinformationofforestlandscape.GPSisusedtoobtainthegrounddataoforientationandguidethepeopletothedifferentplaces.AndGISisusedininformationmanagementandprocessing.