简介:ThispaperhighlightstheresearchanddevelopmentactivitiesbeingdoneonurbanforestryinthePhilippines.TherolethatR&Dplaysinurbanforestryislikewisediscussedintheintroduction.Recommendedtreespeciesforurbanplantingarepresentedincludingtheircharacteristicsanddistribution.Researchesrelatedtourbanforestrybeingconductedarelistedwithashortdescriptionofeachproject.Developmentactivitiesonurbanforestryarelikewisediscussed.Finally,recommendedR&DagendaandresearchableareasbasedonthePhilippineAgenda21andtheDepartmentofEnvironmentandNaturalResources(DENR)R&DFrameworkarepresented.
简介:ThehistoricaltransitionoftimberdistributionpatterninChinawaspresentedfirstlywithmainpartsoftimberflowsinChina,whichincludedtimbermarkets,timbertransportsystemandregulationsoftimbertransport.BasedontheoverviewontropicaltimberflowsinChina,thetradeflowsoftropicaltimberfromproductionandimportsoftropicaltimbertoexportoftropicaltimberproductswereanalyzedbyvividillustrations.Atthesametime,problemsintimbertradeflowsinChinawereanalysedintheend.
简介:20(R)—Rh2是一种次生甙,是红参的特有成分。日本学者研究发现,20(R)—Rhc是一种高活性的抗癌成分,具有独特的逆转作用,但由于红参中含量甚微,直接提取利用得不偿失,极大地限制了20(R)—Rh2的应用开发。吉林人参研究所陶丽华课题组的全体人员,经过八、九年的研究探索,又取得了新的成就。一九八七年他们采用人参地上部分以其中的二醇型人参皂甙为前体物质,利用化学转化方法进行化学结构的修饰改造,最终得到Rh2的纯品。经理化常数测定及13C谱检测,由沈阳药科大学徐绥绪教授确认为20(R)—Rh2。由此,为我国首次采用工业化方法生产人
简介:Inaviewofnaturalconditionsofestablishingnaturereserve,anindexsystemwaspreparedforquantitativeassessmentonstatusofendangeredspecies,andthusdegreeofendangeredspeciesinTibetwasevaluated.Takingasub-ecozoneasbasicunit,top5animalsand1plantwithhighEaswellasthenumberofspeciesineachunitwereenumerated;andthedegreeoflandutilizationwasfiguredout.Afterward,weselected6coefficients,assignedweight,andframedformulatoreckonproportionofnaturereserve,thusanareaofnaturereserveineachsub-ecozonewasobtained.In5schemesofweightassignment,aschemewithmediumareaofnaturereservewasselected.Allsub-ecozoneswereclassifiedinto4gradespriorconservation,1wasingradeA,2ingradeB,2ingradeC,and11ingradeD.Totalplannedareawasapproximately365135km2,about48834km2smallerthantheactualareaof413969km2,ratioofnaturereserveinTibetdiminishesfrom34.4%to30.38%.Basedon3factorsofhumandisturbance,ratioofbuffer-experimentalzoneinproposednaturereservewascalculated.Itwasdemonstratedthatexistingsizeofnaturereservesisexcessiveonthewhole,andtheirdistributionisnotreasonableentirely.Thesizeofnaturereservesin3sub-ecozonesofnorthernChangtangshoulddecrease,anddecrementofareaisapportionedamongother13sub-ecozoneswhichshouldincreasenaturereserve.HeterogeneityofregionaldistributionofrarespeciesinTibetisquiteobvious,soproposedareadistributionofnaturereservesismorescatteredthantheexisting.
简介:TheratesofsoilNmineralizationatsoildepthsof0-15,15-30,30-45and45-0cmandmoistureregimesweremeasuredatthreesand-fixationplantationsofPinussylve.strisvar.mongolicabylaboratoryaerobicincubationmethod.TheresultsshowedthataverageratesofsoilnetN-mineralizationacrosssoildepthvariedfrom1.06to7.52mg~kg1.monthqatsoildepthsfrom0to60cm.Statisticalanalysesindicatedthattheeffectsofdifferentsoildepths,moisturesandtheirinteractionsonnetN-mineralizationratesweresignificant(P<0.05).ThenetN-mineralizationratessignificantlydecreasedwithincreasingsoildepthsandatdepth0-15cmaccountedfor60.52%ofthatatdepthof0-50cm.TherewasnodifferenceinsoilnetN-mineralizationratesbetweenhalfandfully-saturatedwatertreatments,howevertheseratesweresubstantiallyhigherthanthatwithoutwatertreatment(P<0.05).ThefactorsinfluencingNmineralizationprocesshavetobestudiedfurtherinthesesemiaridpineecosystems.