1、Study on Benefit ofEnvironmental friendlyRubber PlantationPOLICY BRIEFDisclaimer:this version is a direct translation of the original Chinese versionBulletin on Lancang-Mekong Environmental Cooperation2The Renaissance of Natural RubberAs a kind of rubber yielding tree planted in alargescalearoundthe

2、world,theheveabrasiliensis has the advantages such as highyield,good quality,long economic life,easylatex exploitation,and fast latex regeneration.Originating in the tropical rainforest in AmazonBasin in South America,during the process ofevolution for thousands of years,the heveabrasiliensisformsth

3、euniquehabitofadaptation to high-temperature,high-humidityand calm wind environment gradually,has thephysiological characteristics of rapid growth,sensitivereactiontolowtemperature,undeveloped wood and mechanical tissue,fragiletrunkvulnerabletowinddamageattacks,and has higher requirement for organic

4、mattercontentofthesoil.Duetosuchcharacteristics,the rubber trees are planted in alimitedareaaroundtheworld.Atpresent,underthe constraints of the planting conditions,90%of the rubber trees in the world are mainlyplantedinThailand,Indonesia,Malaysia,Vietnam and other Southeast Asian countries,as well

5、as a few African countries such asNigeria,indicating that the natural rubber is atypical environmental constraint resource.Byplantingofthenaturalrubber,itispossibletonotonlymeetthedemandsforrelevantproductsinproductionandlife,butalsoenhance the income of farmers,increase theemploymentopportunities,a

6、ndimprovelivelihoods to a great extent.However,it is anindisputable fact that the planting of the naturalrubber leads to the problems in land occupationandfoodsecurity;furthermore,ithasoutstanding negative impact on the ecologicalenvironment,such as loss of tropical rainforest,reduction in biodivers

7、ity,soil erosion,anddecrease in soil fertility.Rubberplantationhasapreferentiallynegativeneteffectonecosystem functions when compared to adjacent tropicalforest(Singh et al.,2021)Bulletin on Lancang-Mekong Environmental Cooperation3Background of construction of environmental friendly rubber forestDe

8、creased soil fertilityThere are few undergrowth vegetation layersand few litter species in the rubber forest.Compared with the tropical rainforest,therubber forest has poor soil fertility.From theperspective of nutrient retention benefit,that ofthe tropical rainforest is 2.11 times as much asthat of

9、 the rubber forest.The soil quality will bedegradedtocertainextentifthenaturalforestisconvertedintotherubberforest.Themonoculture and tapping of the rubber forestwill also cause the loss of soil nutrients easily.Reduced biodiversityDue to the obvious vegetation stratification andthe rich species,the

10、 biodiversity and thegermplasm gene bank are established in thetropical rainforest;however,due to the simplestructure of the community,the diversity andthe stability of species in the rubber forest aredestroyed.Thelarge-scaleplantingoftheheveabrasiliensis leads to the significant decline inthe cover

11、age rate of the tropical rainforest,thedestructionofthehabitatenvironmentofanimalsandplants,thedegradationofecological environment,and the reduction inbiodiversity.Compared with natural forest,thenumber of birds in the pure artificial rubberforest decreases by at least 70%,and thenumber of mammals d

12、ecreases by at least80%.Sharp decline intropical rainforest,lossof biodiversity,andfrequent occurrence ofplant diseases andinsect pests(Li et al.,2007;GuanZhibin et al.,2005;LiJiazhi et al.,2008).Severe soil erosion,change in physical andchemical properties ofsoil,and decrease insoil fertility(Wang

13、Huihai et al.,2003;Pang Jiaping,2009;Yang et al.,2004).Poor waterconservation capacityof rubber forest,andshortage of water inrubber planting area(Tan et al.2011;ZhouWai et al.,2011;ZhouZong and Hu Shaoyun,2008)Changes in localclimate:Decrease innumber of foggy days,reduction in duration ofthick fog

14、,and decline inthe relative humidity(Yu Yan et al.,2007;Dai Bo,2008;Liu et al.,2007).The monoculture of rubber trees in large area leads to a series of problemsin ecological environment,such as:Bulletin on Lancang-Mekong Environmental Cooperation4Decreased water conservation capacityAfter the tropic

15、al rainforest is converted intorubber forest by cutting down,under theinfluence of aggravated soil erosion,the soillayer becomes thinner,the water retentioncapacity and water storage capacity of the soilare degraded,the permeability of the soil isreduced to certain extent,and the waterconservation f

16、unction of the soil is decreased.At the annual scale,the evapotranspiration ofthe rubber forest is larger than that of thetropical rainforest,and the water stored in therubberforestintherainyseasonisnotsufficientto sustain vigorous evapotranspiration in thedry season,resulting in the runoff of the r

17、ubberforest less than that of the tropical rainforest inthe dry season.If a large number of tropicalrainforest is replaced by the single rubberforest,the actual repellency of soil in the rubberforest is higher than that in the tropicalrainforest,resulting in serious soil erosion in therubber forest,

18、while the tropical rainforest withgood vegetation and complex structure haslittle impact on soil erosion.Aggravated plant diseases and insect pestsThe rapid increase in planting area and toosimple planting structure of the rubber forestprovide sufficient space for pests to survive anddevelop,but the

19、re is no suitable habitat fornatural enemies of pests,so it is easy for pestpopulations to“avoid natural enemies,anddevelop and grow stronger”.In addition,the excessive use of ethephon(which can stimulate the yield of rubber)by therubber farmers,even exceeding the safetythreshold,results in the redu

20、ction in resistanceoftherubberforestinthelargearea,thedeclinein the yield of rubber,and the early occurrenceof decline ofrubber trees,which are thedominant factors for serious damage caused bycambium beetle.Fragmentation of tropical rainforestlandscapeMore and more rubber patches are graduallyreplac

21、ing other types of patches,leading to theconvergent development of land utilization inthe rubber planting area.For example,inXishuangbanna,the steep slope and low-grassshrub land at a high altitude of about 1,200 mare evolving into the rubber forest quickly,andthesporadicdistributionofthepatchesincr

22、eases the fragmentation degree of thelandscape.Basedontheanalysisoftheecologicalquantitativeindicators,itcanbeseenthatrubberhasformedtheregionalcharacteristics such as high contrast,segmen-tation and fragmentation.The segmentationand fragmentation of the tropical rainforestlandscape ecosystem will a

23、ffect the materialcycle,energy flow,and species flow in theecosystem.The decline in landscape domi-nance index and the increase in fragmentationmean that the original landscape dominance oftropical rainforest in this region is no longerprominent,theserioussegmentationandfragmentation have occurred,t

24、he hierarchicalstructureofthetropicalrainforesthasundergone the qualitative change,and thesuccession and restoration cycle of the naturalvegetation no longer exists.Bulletin on Lancang-Mekong Environmental Cooperation5Intensified human-animal conflictWith the rapid growth of population,the spaceof p

25、opulation mobility in the rubber plantingarea is increasing gradually,and the areacovered by crops and the construction area ofthe infrastructure are also increasing gradually,exerting certain impact on the wild naturalresource areas.Most wild species,such as theAsian elephant,tend to be found in th

26、e tropicalrainforest that is suitable for rubber cultivation,but due to the gradual decrease in the area ofthe tropical rainforest,the living space of theIn addition to the environmental impact,the rubber industryitself cannot be“immune”.The environmental problems causedby the large-scale planting o

27、f the single rubber will in turn affectthe sustainable development of the rubber industry.wild Asian elephant is reduced to a great extent.Especially in recent years,as the planting areaof the rubber as an economic crop increasesgradually,andthemaximumaltitudeforplanting of the rubber also increases

28、,resultinginmoreoverlappingbetweentherubberplanting area and the living area of the wildspecies area.This not only leads to damage ofthe economic crops,also ruduces living area ofthe wild species,resulting in the human-animalconflict.Bulletin on Lancang-Mekong Environmental Cooperation6Exploration o

29、n planting model and benefit ofenvironmental friendly rubber forestAccording to the principles of ecology andeconomics,by certain biological,ecological andengineering techniques and approaches,it ispossibletoestablishthemultilayerandmultiple-speciescompoundecosystemofrubber forest,which is a kind of

30、 high-efficientartificial ecosystem with the structure andfunctions achieving a stable state of dynamicbalance,and with the impact on environmentfalling within the resource supply capacity andthe environmental self-purification capacity ofits system.This composite ecosystem canachieve the economic y

31、ield of rubber withoutobvious adverse impact on the environment.Schematic diagram illustrating the effect of rubber-based agroforestry on soil physico-chemical properties of rubber planting(Chen et al.,2019)Bulletin on Lancang-Mekong Environmental Cooperation7Jungle-type rubber foresttransformation

32、modeThe jungle-type rubber forest,as a kind ofcompound rubber planting mode constructedby imitating the structure of tropical rainforest,is a balanced and diversified planting mode,meaning the planting of the artificial forestdominated by hevea brasiliensis on the fallowland.The annual yield of rubb

33、er in the jungle-type rubber forest is approximately 640 kghm-2,and the income from rubber yield accountsfor approximately 60%of the total income fromthe forest.In the jungle-type rubber forest,theincomebeforetherubbertappingperiod(approximately 7 years)can be gained by theother grains and crops,and

34、 the main incomegained by the rubber farmers in the later stagecomesfromrubber.Otherplantsgrowingnaturally in the rubber forest can provide fruits,fuelwood,wood and other resources,which aremainly used by farmers for self-sufficiency andalmost require no labor input.This plantingpattern is friendly

35、to small-scale farmers,because it can not only meet the needs of thegrowing population for economic growth,butalso protect the precious forest environment.The commonly used environmental friendly rubber forest transformationmodels include the jungle-type rubber forest transformation mode and theagro

36、forestry rubber forest transformation mode.Agroforestry rubber foresttransformation modeAs an important measure to increase thebenefit of the rubber plantation rapidly andeffectively,the intercropping of rubberplantation can increase the yield of the rubberplantation to a great extent.At present,the

37、intercropping of rubber plantation is carried outmainly in the young rubber plantation.Duringthe sapling period,most crops can beintercropped,while only a few shade-tolerantcrops can be intercropped after growing up,sothe intercropping cycle is short.The rubberyield of the rubber plantation in which

38、 theplanting mode is adjusted and the wide-narrowrow planting is adopted is similar to that of thetraditional rubber plantation.After growing up,more crops can be intercropped,so theintercropping production is allowed during thewhole production cycle.More and more rubberplantations with the whole-cy

39、cle intercroppingmode are used.Bulletin on Lancang-Mekong Environmental Cooperation8To improve the microclimate characteristicsof the compound systemThe suitable intercropping compound eco-system can improve the microclimate in theeco-environment of the rubber plantation.Insummer and autumn at the h

40、igh temperature,itcan reduce the temperature of near-ground airandsurfacesoilsignificantly,reducetheevaporation of soil moisture,and increase theair humidity,so as to mitigate the damage ofhightemperatureanddroughttoheveabrasiliensis.Due to the improved micro-growingenvironment of hevea brasiliensis

41、,and theincreased photosynthetic efficiency and thelightenergyutilizationrateofheveabrasiliensis,thestemdiameterofheveabrasiliensis,especially young hevea brasiliensis,also growbetter.To conserve water and soil,and improve soilefficiencyThe effect of intercropping system of rubberplantation on soil

42、and water conservation andsoil improvement has been verified by a greatnumber of researches.In case of the downslope planting and the cross slope planting forintercropping of pineapple in the young rubberforest,the total runoff is reduced by 1403.23m3/hm2 and 2580.47 m3/hm2,and the totalerosion amou

43、nt is reduced by 560 kg/hm2 and769 kg/hm2,respectively compared with thoseof the rubber forest without planting of thepineapple.The total runoff and the totalerosion amount in the cross slope planting arelower than those in the down slope planting toIn addition to economic benefits,the environmental

44、-friendly rubber forestcan also produce the following ecological benefits:a great extent.By intercropping cinnamon inthe rubber plantation,it is possible to avoid thedirect impact and scouring of rainwater againstthe topsoil,slow down surface runoff,andpromote the infiltration of rainwater into thes

45、oil layer,so as to prevent the soil erosion inthe rubber plantation and increase the waterstorage in the soil layer.Furthermore,it isfound that the intercropping can increase thesoil available nutrients,improve the soilstructure,and improve the soil fertility to agreat extent.To improve the biodiver

46、sity and stability ofthe systemWith multiple components,complex systemstructure,and good ecological environment,itis possible to improve the biodiversity of theintercropping compound system in the rubberplantation.The number of birds recorded in theenvironmental-friendly ecological rubberplantation

47、is much more than that recorded inthe pure rubber forest,and the habitat selectedby birds shows the characteristics of forestthicket nearshore water area environmental-friendly ecological rubberplantation pure forest.In the soil layer withthe depth of 0-10 cm,the amount of roots inthe sole cropping

48、rubber plantation is lesscompared with that in the intercropping rubberplantation,so as to provide enough space forthe survival and reproduction of soil animals.However,within the scope of in the rubber-teacommunity forest,most of the roots occupiesthe soil space,leading to the decrease in thenumber

49、 of soil animals.The termite richness inBulletin on Lancang-Mekong Environmental Cooperation9the agroforestry planting mode dominated byrubber is higher than that of the sole croppingrubber plantation,playing a positive role in theconservation of termite diversity.The soil in the rubber plantation w

50、ithintercropping has a higher microbial biomassand a shorter microbial transformation cyclethan that in the sole cropping rubberplantation,resulting in more forest-substituteland per year.By intercropping in the youngLancang-Mekong Environmental Cooperation CenterForeign Cooperation and Exchange Cen

51、terof Ecological Environment Department No.5,Houyingfang Lane,Xicheng District,BeijingZip Code:100035Tel:+86-10-82268256/8221Fax:+86-10-82200579Email:Website:http:/WeChat Official Account:lancang-mekongecThis knowledge product was prepared underthe context of the project“Improving Eco-system Managem

52、ent for Sustainable Liveli-hoodswithintheFrameworkofLancang-Mekong Cooperation”,funded by the Ministry ofEcologyandEnvironmentofthePeoplesRepublic of China,through the China Trust Fundto UNEP.This project is implemented jointly bythe United Nations Environment Programme(UNEP)Regional Office for Asia

53、 and the Pacific,in partnership with UNEP International Eco-systemManagementPartnershipandtheLancang-Mekong Environmental CooperationCentre,as well as the Biodiversity,People andLandscapes Unit of UNEP Ecosystems Division.Find out more about the project hereContact Usrubber plantation,it is possible

54、 to improve theurease and phosphatase activity of the soil inthe rubber plantation.By intercropping ofkudzu in the young rubber plantation,it ispossible to improve catalase and polyphenoloxidase activity of the soil in the young rubberplantation.In addition,the communitystructure constructed by compound planting ofrubber and dictyophora can improve thefunctional diversity of the soil microbialcommunity.