Background： The quantitative impact of forest management on forests＇ wood resource was evaluated for Picea and Fagus mixed forests. The effects on the productivity of tendering operations, thinnings and rotation len...Background： The quantitative impact of forest management on forests＇ wood resource was evaluated for Picea and Fagus mixed forests. The effects on the productivity of tendering operations, thinnings and rotation length have seldom been directly quantified on landscape scale. Methods： Two sites of similar fertility but subject to contrasted forest management were studied with detailed inventories： one in Germany, the other in Romania, and compared with the respective national forest inventories. In Romania, regulations impose very long rotations, low thinnings and a period of no-cut before harvest. In contrast, tending and thinnings are frequent and intense in Germany. Harvests start much earlier and must avoid clear cutting but maintain a permanent forest cover with natural regeneration. While Germany has an average annual wood increment representative for Central Europe, Romania represents the average for Eastern Europe. Results： The lack of tending and thinning in the Romanian site resulted in twice as many trees per hectare as in the German site for the same age. The productivity in Romanian production forests was 20 % lower than in Germany despite a similar fertility. The results were supported by the data from the national forest inventory of each country, which confirmed that the same differential exists at country scale. Furthermore, provided the difference in rotation length, two crops are harvested in Germany when only one is harvested in Romania. The losses of production due to a lower level of management in Romania where estimated to reach 12.8 million m3.y-1 in regular mountain production forests, and to 15 million m3.y-1 if managed protection forest is included. Conclusions： The productivity of Picea and Fagus mountain forests in Romania is severely depressed by the lack of tending and thinning, by overly long rotations and the existence of a 25-years no-cut period prior to harvest. The average standing volume in Germany was 50 % lower than in Romania, but the higher harvesting rate resulted in more than doubling wood production. Considering the mitigation effects of climate change by forests, it emerges that the increase in standing volume of forests in Romania is smaller than the additional harvest in Germany which serves fossil fuel substitution.展开更多
Anaerobic digestion(AD)has been considered as a promising technique for food waste(FW)recycling.However,the accumulation of volatile fatty acids(VFAs)restricts the stability of anaerobic reactors.The present study inv...Anaerobic digestion(AD)has been considered as a promising technique for food waste(FW)recycling.However,the accumulation of volatile fatty acids(VFAs)restricts the stability of anaerobic reactors.The present study investigated the use of biochar produced at different conditions(750℃-30 min,750℃-60 min,750℃-120 min,550℃-60 min,650℃-60 min,850℃-60 min,950℃-60 min)for enhancing the AD of FW.Batch experiments showed that all the biochar increased the methane production rates and biochar obtained at 750℃-60 min resulted in the highest enhance-ment by 21.5%.It was further showed surface oxygen-containing functional groups and graphitization degree of biochar were the critical factors for improving methane production.Microbial analysis showed that biochar addi-tion formed different microbial communities,and Methanosaeta,Romboutsia,and norank_f_Anaerolineaceae were enriched,which might be correlated with direct interspecies electron transfer(DIET).This research showed biochar could enhance the AD of FW and also revealed the main characteristics of biochar relating with the enhancement of AD.展开更多
基金support by a grant of the Romanian National Authority for Scientific Research,CNCS-UEFISCDI,project number PN-II-ID-PCE-2011-3-0781support by a grant of the Romanian National Authority for Scientific Research,CNCS-UEFISCDI,project number PN-II-RU-TE-2014-4-0017
文摘Background： The quantitative impact of forest management on forests＇ wood resource was evaluated for Picea and Fagus mixed forests. The effects on the productivity of tendering operations, thinnings and rotation length have seldom been directly quantified on landscape scale. Methods： Two sites of similar fertility but subject to contrasted forest management were studied with detailed inventories： one in Germany, the other in Romania, and compared with the respective national forest inventories. In Romania, regulations impose very long rotations, low thinnings and a period of no-cut before harvest. In contrast, tending and thinnings are frequent and intense in Germany. Harvests start much earlier and must avoid clear cutting but maintain a permanent forest cover with natural regeneration. While Germany has an average annual wood increment representative for Central Europe, Romania represents the average for Eastern Europe. Results： The lack of tending and thinning in the Romanian site resulted in twice as many trees per hectare as in the German site for the same age. The productivity in Romanian production forests was 20 % lower than in Germany despite a similar fertility. The results were supported by the data from the national forest inventory of each country, which confirmed that the same differential exists at country scale. Furthermore, provided the difference in rotation length, two crops are harvested in Germany when only one is harvested in Romania. The losses of production due to a lower level of management in Romania where estimated to reach 12.8 million m3.y-1 in regular mountain production forests, and to 15 million m3.y-1 if managed protection forest is included. Conclusions： The productivity of Picea and Fagus mountain forests in Romania is severely depressed by the lack of tending and thinning, by overly long rotations and the existence of a 25-years no-cut period prior to harvest. The average standing volume in Germany was 50 % lower than in Romania, but the higher harvesting rate resulted in more than doubling wood production. Considering the mitigation effects of climate change by forests, it emerges that the increase in standing volume of forests in Romania is smaller than the additional harvest in Germany which serves fossil fuel substitution.
基金Science and Technology Commission of Shanghai Municipality(19DZ1204704,22ZR1405900)National Natural Science Foundation of China(31970117)Hong Kong Environment and Conservation Fund(Project 101/2020).
文摘Anaerobic digestion(AD)has been considered as a promising technique for food waste(FW)recycling.However,the accumulation of volatile fatty acids(VFAs)restricts the stability of anaerobic reactors.The present study investigated the use of biochar produced at different conditions(750℃-30 min,750℃-60 min,750℃-120 min,550℃-60 min,650℃-60 min,850℃-60 min,950℃-60 min)for enhancing the AD of FW.Batch experiments showed that all the biochar increased the methane production rates and biochar obtained at 750℃-60 min resulted in the highest enhance-ment by 21.5%.It was further showed surface oxygen-containing functional groups and graphitization degree of biochar were the critical factors for improving methane production.Microbial analysis showed that biochar addi-tion formed different microbial communities,and Methanosaeta,Romboutsia,and norank_f_Anaerolineaceae were enriched,which might be correlated with direct interspecies electron transfer(DIET).This research showed biochar could enhance the AD of FW and also revealed the main characteristics of biochar relating with the enhancement of AD.
