Background:There is an urgent need for quantifying the terrestrial carbon sink in the context of global carbon emissions.However,neither the flux measurements,nor the national wood balances fulfil this purpose.In this...Background:There is an urgent need for quantifying the terrestrial carbon sink in the context of global carbon emissions.However,neither the flux measurements,nor the national wood balances fulfil this purpose.In this discussion article we point at various shortcomings and necessary improvements of these approaches in order to achieve a true quantification of the carbon exchange of land surfaces.Results:We discuss the necessity of incorporating all lateral fluxes,but mainly the export of biomass by harvest,into the flux balance and to recognize feedbacks between management and fluxes to make flux measurements compatible with inventories.At the same time,we discuss the necessity that national reports of wood use need to fully recognize the use of wood for energy use.Both approaches of establishing an ecosystem carbon balance,fluxes and inventories,have shortcomings.Conclusions:Including harvest and feedbacks by management appears to be the main requirement for the flux approach.A better quantification of wood use for bioenergy seems a real need for integrating the national wood balances into the global carbon cycle.展开更多
Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on b...Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on biomass stocks has rarely been analysed on a large scale based on measurements. Two hypotheses prevail: management induces a reduction of wood stocks due to cuttings, versus no impact because of increased growth of the remaining trees. Using data collected for 2840 permanent plots across Romania from the National Forest Inventory representing^2.5 Mha, we have tested to what extent different management types and treatments can influence the biomass stock and productivity of beech forests, and attempt to quantify these effects both on the short and long terms. Three main types of beech forest management are implemented in Romania with specific objectives: intensive wood production in production forests, protection of ecosystem services (e.g. watersheds, avalanche protection) in protection forests, and protection of the forest and its biodiversity in protected forests. Production forests encompass two treatments differing according to the stand regeneration method: the age class rotation management and the group shelterwood management. Results: We show that forest management had little influence on the biomass stocks at a given stand age. The highest stocks at stand age 100 were observed in production forests (the most intensively managed forests). Consequences of early cuttings were very short-termed because the increase in tree growth rapidly compensated for tree cuttings. The cumulated biomass of production forests exceeded that of protected and protection forests. Regarding the treatment, the group shelterwood forests had a markedly higher production over a full rotation period. The total amount of deadwood was primarily driven by the amount of standing deadwood, and no management effect was detected. Conclusions: Given the relatively low-intensity management in Romania, forest management had no negative impact on wood stocks in beech forests biomass stocks at large scale. Stand productivity was very similar among management types or treatments. However cumulated biomass in production forests was higher than in protection or protected forests, and differed markedly according to treatments with a higher cumulated biomass in shelterwood forests.展开更多
Background： Two approaches mark the difference between the ＂ecological＂ and ＂agricultural＂ view of the biodiversity/ growth relation. In ecology the trend is averaged by taking monocultures of all species as base...Background： Two approaches mark the difference between the ＂ecological＂ and ＂agricultural＂ view of the biodiversity/ growth relation. In ecology the trend is averaged by taking monocultures of all species as baseline to evaluate mixtures. This contrasts the ＂agricultural＂ view focusing on the most productive species or species combination as baseline to evaluate mixtures. The present study investigates the change of highest rates （maximum） productivities in grasslands and forests with increasing plant （or tree） diversity, and compares these with the average response. Methods： We base our analysis on existing published datasets relating the growth of plant stands （growth rate per land area） to the diversity on the same plot. We use a global dataset （Ellis et al. 2012 and MODIS-data, see Fig. 1）, the grassland experiment in lena （Buchmann et al. 2017）, the regional study on forests in Romania and Germany by Bouriaud et al. （2016）, and data from the German National Forest inventory （BWl 3, see Fig. 3）. In all cases the average response of growth to changes in biodiversity as well as the boundary line of the maximum values was calculated. Results： in both vegetation types a decreasing trend of maximum productivity with any added species emerges, contrasting the average trend that was positive in grassland, but absent in forests. The trend of maximum values was non-significant in grasslands probably due to the fact that not all combinations of species mixtures were available. In temperate forests, maximum productivity decreases significantly by about 10% in regional studies and by 8% at national scale with each added species. Maximum biomass per area was the same for managed and unmanaged conditions. A global assessment of NPP and biodiversity could also not confirm a general positive biodiversity- productivity relationship. Conclusions： Managed grasslands and forests reach highest productivity and volumes at low diversity. Also globally we could not confirm a biodiversity effect on productivity. Despite this, for long-living organisms, such as trees, the incentive for land managers exists to reduce the risk of failure due to climate extremes and diseases by taking a loss in productivity into account and to actively maintain a mixture of species.展开更多
文摘Background:There is an urgent need for quantifying the terrestrial carbon sink in the context of global carbon emissions.However,neither the flux measurements,nor the national wood balances fulfil this purpose.In this discussion article we point at various shortcomings and necessary improvements of these approaches in order to achieve a true quantification of the carbon exchange of land surfaces.Results:We discuss the necessity of incorporating all lateral fluxes,but mainly the export of biomass by harvest,into the flux balance and to recognize feedbacks between management and fluxes to make flux measurements compatible with inventories.At the same time,we discuss the necessity that national reports of wood use need to fully recognize the use of wood for energy use.Both approaches of establishing an ecosystem carbon balance,fluxes and inventories,have shortcomings.Conclusions:Including harvest and feedbacks by management appears to be the main requirement for the flux approach.A better quantification of wood use for bioenergy seems a real need for integrating the national wood balances into the global carbon cycle.
基金funding from the European Union Seventh Framework Program(FP7/2007–2013)under grant agreement n°244122support by a grant of the Romanian National Authority for Scientific Research,CNCS-UEFISCDI,project number PN-II-IDPCE-2011-3-0781support of the University of Antwerp Research Council through its Methusalem program
文摘Background: Forest management aims at obtaining a sustainable production of wood to be harvested to generate products or energy. However, the quantitative influence of forest management and of removals by harvest on biomass stocks has rarely been analysed on a large scale based on measurements. Two hypotheses prevail: management induces a reduction of wood stocks due to cuttings, versus no impact because of increased growth of the remaining trees. Using data collected for 2840 permanent plots across Romania from the National Forest Inventory representing^2.5 Mha, we have tested to what extent different management types and treatments can influence the biomass stock and productivity of beech forests, and attempt to quantify these effects both on the short and long terms. Three main types of beech forest management are implemented in Romania with specific objectives: intensive wood production in production forests, protection of ecosystem services (e.g. watersheds, avalanche protection) in protection forests, and protection of the forest and its biodiversity in protected forests. Production forests encompass two treatments differing according to the stand regeneration method: the age class rotation management and the group shelterwood management. Results: We show that forest management had little influence on the biomass stocks at a given stand age. The highest stocks at stand age 100 were observed in production forests (the most intensively managed forests). Consequences of early cuttings were very short-termed because the increase in tree growth rapidly compensated for tree cuttings. The cumulated biomass of production forests exceeded that of protected and protection forests. Regarding the treatment, the group shelterwood forests had a markedly higher production over a full rotation period. The total amount of deadwood was primarily driven by the amount of standing deadwood, and no management effect was detected. Conclusions: Given the relatively low-intensity management in Romania, forest management had no negative impact on wood stocks in beech forests biomass stocks at large scale. Stand productivity was very similar among management types or treatments. However cumulated biomass in production forests was higher than in protection or protected forests, and differed markedly according to treatments with a higher cumulated biomass in shelterwood forests.
文摘Background： Two approaches mark the difference between the ＂ecological＂ and ＂agricultural＂ view of the biodiversity/ growth relation. In ecology the trend is averaged by taking monocultures of all species as baseline to evaluate mixtures. This contrasts the ＂agricultural＂ view focusing on the most productive species or species combination as baseline to evaluate mixtures. The present study investigates the change of highest rates （maximum） productivities in grasslands and forests with increasing plant （or tree） diversity, and compares these with the average response. Methods： We base our analysis on existing published datasets relating the growth of plant stands （growth rate per land area） to the diversity on the same plot. We use a global dataset （Ellis et al. 2012 and MODIS-data, see Fig. 1）, the grassland experiment in lena （Buchmann et al. 2017）, the regional study on forests in Romania and Germany by Bouriaud et al. （2016）, and data from the German National Forest inventory （BWl 3, see Fig. 3）. In all cases the average response of growth to changes in biodiversity as well as the boundary line of the maximum values was calculated. Results： in both vegetation types a decreasing trend of maximum productivity with any added species emerges, contrasting the average trend that was positive in grassland, but absent in forests. The trend of maximum values was non-significant in grasslands probably due to the fact that not all combinations of species mixtures were available. In temperate forests, maximum productivity decreases significantly by about 10% in regional studies and by 8% at national scale with each added species. Maximum biomass per area was the same for managed and unmanaged conditions. A global assessment of NPP and biodiversity could also not confirm a general positive biodiversity- productivity relationship. Conclusions： Managed grasslands and forests reach highest productivity and volumes at low diversity. Also globally we could not confirm a biodiversity effect on productivity. Despite this, for long-living organisms, such as trees, the incentive for land managers exists to reduce the risk of failure due to climate extremes and diseases by taking a loss in productivity into account and to actively maintain a mixture of species.
