There is widespread interest in estimating and forecasting individual tree and forest growth rates for restoration and carbon sequestration objectives. Outside intensively managed forests, past attempts have been limi...There is widespread interest in estimating and forecasting individual tree and forest growth rates for restoration and carbon sequestration objectives. Outside intensively managed forests, past attempts have been limited by the lack of accurate long-term monitoring in multi-age mixed native forests to provide estimates of both expected mean diameter increments and the statistical variation in those estimates. A dataset from Eucalyptus-dominated native forests in subtropical Queensland, Australia offers an opportunity to provide accurate estimates of tree and forest growth rates. Over 86,400 trees from 155 native species were identified and remeasured between 1936 and 2011 in 641 permanent sample plots across a 500-2000 mm mean annual rainfall gradient. Individual tree diameter at breast height （DBH） increments observed for all species ranged mainly from 0.01 to 0.5 cm yr-1 （94 % of values）, with consistentdifferences between rainfall zones （mean of 500- 2000 mm yr-1）, and varying differences between species （155） and stem diameter class （10-100 cm）. For some spe- cies, diameter increment increased progressively with rain- fall （e.g. Eucalyptus siderophloia, Eucalyptus propinqua, and Lophostemon confertus）, but in others （e.g. Corymbia citriodora subsp, variegata, Corymbia intermedia, and Eucalyptus biturbinata） the greatest diameter increments were recorded between 1200 and 1600 mm yr-1. Where there were sufficient data, most species exhibited a quadratic relationship between DBH increment and DBH class, but two species （ Callitris glaucophylla and Eucalyptus crebra） native to the 500-800 mm annual rainfall zone showed lin- ear increases in DBH increment with increasing DBH. Continued monitoring of these plots would add to their already great value.展开更多
Crop production models are highly developed to account for different nitrogen, light, temperature and water availability conditions and, in some species, disease or air pollutant effects. There is very limited knowled...Crop production models are highly developed to account for different nitrogen, light, temperature and water availability conditions and, in some species, disease or air pollutant effects. There is very limited knowledge on responses of many tropical crops, such as oil palm (Elaeis guineensis), to air pollutants although predictions of these effects are essential for industrial planning in several countries. In the absence of limitations due to water supply, the effects of leaf area loss due to necrosis and chlorosis are much more important to canopy photosynthesis than are changes in the physiological attributes that influence the efficiency of light use. Therefore, potential losses of crop production due to air pollutants such as fluoride can be inferred usefully from the extent of visible injury to foliage that may be associated with different levels of pollutant exposure.展开更多
The nature and extent of environmental disturbance associated with mining commonly entails completely new and challenging combinations of climate,lithology and landform.Consequently,the outcomes of ecological processe...The nature and extent of environmental disturbance associated with mining commonly entails completely new and challenging combinations of climate,lithology and landform.Consequently,the outcomes of ecological processes associated with the recovery or restoration of ecosystems cannot be predicted reliably from previously known associations between their physical and biological components.For radically disturbed sites,we propose that it is not practicable to aim for the restoration of historical ecosystems.However,hybrid(reversibly different)or novel(irreversibly different)ecosystems comprising new combinations of physical and biological components,including both native and non-native species,could provide levels of stability and functionality acceptable to all stakeholders and within feasible management regimes.We propose that limiting physical conditions of the landscape can be identified and managed,and that alternative species combinations for introduction to these new landscapes may be considered with cautious optimism.展开更多
文摘There is widespread interest in estimating and forecasting individual tree and forest growth rates for restoration and carbon sequestration objectives. Outside intensively managed forests, past attempts have been limited by the lack of accurate long-term monitoring in multi-age mixed native forests to provide estimates of both expected mean diameter increments and the statistical variation in those estimates. A dataset from Eucalyptus-dominated native forests in subtropical Queensland, Australia offers an opportunity to provide accurate estimates of tree and forest growth rates. Over 86,400 trees from 155 native species were identified and remeasured between 1936 and 2011 in 641 permanent sample plots across a 500-2000 mm mean annual rainfall gradient. Individual tree diameter at breast height （DBH） increments observed for all species ranged mainly from 0.01 to 0.5 cm yr-1 （94 % of values）, with consistentdifferences between rainfall zones （mean of 500- 2000 mm yr-1）, and varying differences between species （155） and stem diameter class （10-100 cm）. For some spe- cies, diameter increment increased progressively with rain- fall （e.g. Eucalyptus siderophloia, Eucalyptus propinqua, and Lophostemon confertus）, but in others （e.g. Corymbia citriodora subsp, variegata, Corymbia intermedia, and Eucalyptus biturbinata） the greatest diameter increments were recorded between 1200 and 1600 mm yr-1. Where there were sufficient data, most species exhibited a quadratic relationship between DBH increment and DBH class, but two species （ Callitris glaucophylla and Eucalyptus crebra） native to the 500-800 mm annual rainfall zone showed lin- ear increases in DBH increment with increasing DBH. Continued monitoring of these plots would add to their already great value.
文摘Crop production models are highly developed to account for different nitrogen, light, temperature and water availability conditions and, in some species, disease or air pollutant effects. There is very limited knowledge on responses of many tropical crops, such as oil palm (Elaeis guineensis), to air pollutants although predictions of these effects are essential for industrial planning in several countries. In the absence of limitations due to water supply, the effects of leaf area loss due to necrosis and chlorosis are much more important to canopy photosynthesis than are changes in the physiological attributes that influence the efficiency of light use. Therefore, potential losses of crop production due to air pollutants such as fluoride can be inferred usefully from the extent of visible injury to foliage that may be associated with different levels of pollutant exposure.
基金the two anonymous reviewers and vip-Editor(M Perring)for their beneficial commentary which contributed highly to improving this manuscript for publication.Special thanks are also extended to M Perring and RJ Hobbs for providing early access to the compilation book Novel ecosystems:Intervening in the new ecological world order by RJ Hobbs,ES Higgs and CM Hall(eds).This study was made possible by funding to P.Audet from The University of Queensland and the Natural Sciences and Engineering Research Council(NSERC)of Canada.
文摘The nature and extent of environmental disturbance associated with mining commonly entails completely new and challenging combinations of climate,lithology and landform.Consequently,the outcomes of ecological processes associated with the recovery or restoration of ecosystems cannot be predicted reliably from previously known associations between their physical and biological components.For radically disturbed sites,we propose that it is not practicable to aim for the restoration of historical ecosystems.However,hybrid(reversibly different)or novel(irreversibly different)ecosystems comprising new combinations of physical and biological components,including both native and non-native species,could provide levels of stability and functionality acceptable to all stakeholders and within feasible management regimes.We propose that limiting physical conditions of the landscape can be identified and managed,and that alternative species combinations for introduction to these new landscapes may be considered with cautious optimism.
