简介：Woodpropertiesfrom28trees(Populuseuramericana)selectedfromhealthyandacidraindamagedforestweremeasuredtoevaluatethepossibleimpactsonwoodqualityandutilization.Ontheheavilydamagedlocation,thepHvalueofprecipitationrangedfrom3.7-5.0,andsulfateloadingrangedfrom20-40kg·ha-2.y-1.Quantitativeandqualitativestudiesonringwidth,physicalpropertiesandmechanicalpropertiesindicatedthatchangesofwoodpropertiesbetweendiseasedandhealthypoplaroccurred.Aci...

简介：Theeffectsofsimulatedacidrainretainedinsoilonthepropertiesofacidsoilanditsdiminishingbyapplicationofgroundphosphaterockwereinvestigatedbyusingthesorptionmethod.Resultsshowasfollows:(1)Foryellowbrownsoil,theeffectofsimulatedacidrainonthepropertiesofsoilwithapHvalueof5.9wasrelativelysmall,exceptagreatquantityofacidraindepositedonit.(2)forredsoil,theeffectofsimulatedacidrainonthepropertiesofsoilwassignificant.Withtheincreaseoftheamountofaciddeposition,thepHvalueofsoilwasdeclined,butthecontentsofexchangeableH^+,Al^3+andMn^2+andtheamountofSO4^1-retentionwereincreased.(3)Manypropertiesofacidsoilscouldbeimprovedbyapplyinggroundphosphaterock.Forexample,pHvalueofsoilsandtheamountsofavailablePandexchangeableCa^2+andMg^2+wereincreased,andtheamountsofexchangeableH^+andAl^3+andSO4^2-retainedwasreduced.Theapplicationofgroundposphaterockcouldeffctivelydiminishthepollutionofacidraintosoil.

简介：Basedoninvestigationof53gapsand25quadrats(15m×15meach)ofnon-gapclosedstandinanold-growthtropicalmontanerainforestofHainanIsland,China,canopydisturbanceregimesandgapregenerationwerestudied.Gapswereellipticalinhorizontalform,theratiooflongaxis/shortaxiswasabout1.4.Percentageofexpandedgaps(EG)andcanopygaps(CG)areainthelandscapewere53.5%and25.2%respectively.EGrangedfrom31.4m2to488.2m2andCG/rom14.9m2to354.2m2,theiraveragesizes...