Trade-off And Synergy Analysis Of Ecosystem Services Of Subtropical Secondary Forests In Southern China

Forest ecosystems can hold as many ecosystem services(ESs),such as carbon sequestration,preventing soil erosion and keeping fertility,providing products and holding biodiversity,it also play an important role for global ecosystem and human well-being.With the developing of society economic and increasing of population,forest ecosystem structure have been destroyed.Our paper selected three secondary forests,including Pinus massoniana-Lithocarpus glaber coniferous broadleaved forest,Choerospondias axillaris deciduous broadleaved forest and Cyclobalanopsis glauca-Lithocarpus glaber evergreen broadleaved forest to quantify the ESs in subtropical forests.Three kinds of ESs,biodiversity ESs,regulating ESs(including climate regulating,air quality regulating,soil carbon and nitrogen storage regulating)and providing ESs(including energy and timber providing),were chosen.In this study,we firstly compared the differences of indicators of ESs between three secondary forests,and then quantified those indicators.We used the root mean square deviation method(RMSD)to quantify the trade-off and synergy relationship between ESs and explored the impact factors(i.e.terrain and species composition).The results were as follows:(1)Forest can affect the ESs indicators in this study.For biodiversity,C.axillaris deciduous broadleaved forest was significantly higher than P.massoniana-L.glaber coniferous broadleaved forest and C.glauca-L.glaber evergreen broadleaved forest(p<0.05),but those two forests have no significant difference.Although C.axillaris deciduous broadleaved forest and C.glauca-L.glaber evergreen broadleaved forest were not significantly different,they were significantly higher than P.massoniana-L.glaber coniferous broadleaved forest(P<0.05).In the pairwise comparision,it was found that CO2.equ.,biomass and basal area(BA)were significantly higher in P.massoniana-L.glaber coniferous broadleaved forest,followed by C.glauca-L.glaber evergreen broadleaved forest and upland C.axillaris deciduous broadleaved forest(P<0.05).Furthermore,lead area index(LAI)as being significantly higher in C glauca-L.glaber evergreen broadleaved forest than in C.axillaris deciduous broadleaved forest,however,those two secondary forests showed consistent result that had no significant difference compared to P.massoniana-L.glaber coniferous broadleaved forest.(2)Forest type had different effects on ESs trade-off and synergy relationship.Among three forest types,the highest trade-off occurred with biodiversity-related ESs pairs,and biodiversity had a relatively higher benefit.On the whole,soil organic carbon storage(SOCS)regulating and soil total nitrogen storage(TNS)fell mostly on the 1:1 line in the scatter plot for three secondary forests,suggesting a very low trade-off between SOCS and TNS.For the pairs of climate regulating and energy regulating,they all completely fell on the 1:1 line,indicating a synergy relationship between those two ESs.Timber providing showed a consistently relatively higher benefit when trade-off with climate regulating and energy providing.In addition,other trade-off relationships between ESs pairs showed different relatively higher benefit or had no fixed team with relatively higher benefit.(3)The relationship between ESs may be influenced by terrain(including elevation and convex concave)and species composition.The trade-off between TNS regulating and timber providing in P.massoniana-L.glaber coniferous broadleaved forest was influenced by elevation,but not convex concave.Trade-off relationship between air quality regulating and biodiversity in C.axillaris deciduous broadleaved forest was influenced by both elevation and convex concave,but this relationship in C.glauca-L.glaber evergreen broadleaved forest was effected by overall species composition.In summary,this study compared the differences in ESs indicators and explored the trade-off or synergy relationship between ESs pairs in three secondary forests.Finally,we have found the impossible impact factors on affecting trade-off or synergy relationship between ESs pairs.The results of this study may afford science support for forest management and utilizing,it can also help to formulate relevant policy based on the relationship between ESs.