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
The European MOTTLES project set-up a newgeneration network for ozone(O 3)monitoring in 17 plots in France,Italy and Romania.These monitoring stations allowed:(1)estimating the accumulated exposure AOT40 and stomatal ...The European MOTTLES project set-up a newgeneration network for ozone(O 3)monitoring in 17 plots in France,Italy and Romania.These monitoring stations allowed:(1)estimating the accumulated exposure AOT40 and stomatal O 3 fl uxes(PODY)with an hourly threshold of uptake(Y)to represent the detoxifi cation capacity of trees(POD1,with Y=1 nmol O 3 m^−2 s^−1 per leaf area);and(2)collecting data of forest-response indicators,i.e.crown defoliation and visible foliar O 3-like injury over the time period 2017–2019.The soil water content was the most important parameter aff ecting crown defoliation and was a key factor aff ecting the severity of visible foliar O 3-like injury on the dominant tree species in a plot.The soil water content is thus an essential parameter in the PODY estimation,particularly for water-limited environments.An assessment based on stomatal fl ux-based standard and on real plant symptoms is more appropriated than the exposure-based method for protecting vegetation.From fl ux-eff ect relationships,we derived fl ux-based critical levels(CLef)for forest protection against visible foliar O 3-like injury.We recommend CLef of 5 and 12 mmol m^−2 POD1 for broadleaved species and conifers,respectively.Before using PODY as legislative standard in Europe,we recommend using the CLec for≥25%of crown defoliation in a plot:17,000 and 19,000 nmol mol^−1 h AOT40 for conifers and broadleaved species,respectively.展开更多
Correction to:J.For.Res.https://doi.org/10.1007/s11676-020-01191-x In the Original publication of the article,the authors found an error in the text“We recommend CLef of 5 and 12 mmol m−2 POD1 for broadleaved species...Correction to:J.For.Res.https://doi.org/10.1007/s11676-020-01191-x In the Original publication of the article,the authors found an error in the text“We recommend CLef of 5 and 12 mmol m−2 POD1 for broadleaved species and conifers,respectively”under the section abstract and conclusion.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
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This work was supported by the LIFE fi nancial instrument of the European Union in the framework of the MOTTLES project“Monitoring ozone injury for setting new critical levels”(LIFE15 ENV/IT/000183).
文摘The European MOTTLES project set-up a newgeneration network for ozone(O 3)monitoring in 17 plots in France,Italy and Romania.These monitoring stations allowed:(1)estimating the accumulated exposure AOT40 and stomatal O 3 fl uxes(PODY)with an hourly threshold of uptake(Y)to represent the detoxifi cation capacity of trees(POD1,with Y=1 nmol O 3 m^−2 s^−1 per leaf area);and(2)collecting data of forest-response indicators,i.e.crown defoliation and visible foliar O 3-like injury over the time period 2017–2019.The soil water content was the most important parameter aff ecting crown defoliation and was a key factor aff ecting the severity of visible foliar O 3-like injury on the dominant tree species in a plot.The soil water content is thus an essential parameter in the PODY estimation,particularly for water-limited environments.An assessment based on stomatal fl ux-based standard and on real plant symptoms is more appropriated than the exposure-based method for protecting vegetation.From fl ux-eff ect relationships,we derived fl ux-based critical levels(CLef)for forest protection against visible foliar O 3-like injury.We recommend CLef of 5 and 12 mmol m^−2 POD1 for broadleaved species and conifers,respectively.Before using PODY as legislative standard in Europe,we recommend using the CLec for≥25%of crown defoliation in a plot:17,000 and 19,000 nmol mol^−1 h AOT40 for conifers and broadleaved species,respectively.
文摘Correction to:J.For.Res.https://doi.org/10.1007/s11676-020-01191-x In the Original publication of the article,the authors found an error in the text“We recommend CLef of 5 and 12 mmol m−2 POD1 for broadleaved species and conifers,respectively”under the section abstract and conclusion.
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.
