We performed a biomass inventory using two-phase sampling to estimate biomass and carbon stocks for mecrusse woodlands and to quantify errors in the estimates. The first sampling phase involved measurement of auxiliar...We performed a biomass inventory using two-phase sampling to estimate biomass and carbon stocks for mecrusse woodlands and to quantify errors in the estimates. The first sampling phase involved measurement of auxiliary variables of living Androstachys johnsonii trees;in the second phase, we performed destructive biomass measurements on a randomly selected subset of trees from the first phase. The second-phase data were used to fit regression models to estimate below and aboveground biomass. These models were then applied to the first-phase data to estimate biomass stock. The estimated forest biomass and carbon stocks were 167.05 and 82.73 Mg·ha-1, respectively. The percent error resulting from plot selection and allometric equations for whole tree biomass stock was 4.55% and 1.53%, respectively, yielding a total error of 4.80%. Among individual variables in the first sampling phase, diameter at breast height (DBH) measurement was the largest source of error, and tree-height estimates contributed substantially to the error. Almost none of the error was attributable to plot variability. For the second sampling phase, DBH measurements were the largest source of error, followed by height measurements and stem-wood density estimates. Of the total error (as total variance) of the sampling process, 90% was attributed to plot selection and 10% to the allometric biomass model. The total error of our measurements was very low, which indicated that the two-phase sampling approach and sample size were effective for capturing and predicting biomass of this forest type.展开更多
In Daloa,the waters from wells and springs from shallow aquifers are used for drinking,given the low water coverage and organoleptic quality of water from the public network.However,the lack of an adequate sewage syst...In Daloa,the waters from wells and springs from shallow aquifers are used for drinking,given the low water coverage and organoleptic quality of water from the public network.However,the lack of an adequate sewage system and human activities could lead to a risk of chemical contamination of this water table.Yet,the vulnerability and contamination of groundwater in urban areas are a major concern that requires greater attention.It therefore seems necessary to map the specific vulnerability linked to chromium in order to identify the areas requiring special attention.To do this,we opted for Multi-Criteria Analysis,which takes many parameters into account and is suitable for porous media.This method is based on a numerical rating system,which takes into account hydrogeological,human and pollutant characteristics.Field data,laboratory data and maps were used.Using ArcGis software,the data was interpolated,reclassified and rated.The combination of maps indicates three classes of vulnerability:average(0.79%),high(97.53%)and very high(1.68%),with satisfactory validation criteria(coincidence rate:78.26%and margin of error 0.68%).Consequently,there is a potential risk of contamination of alterite aquifers throughout the city.The MCA has produced satisfactory results,but these can be supplemented by a numerical mass transport model to validate the degree of vulnerability.展开更多
文摘We performed a biomass inventory using two-phase sampling to estimate biomass and carbon stocks for mecrusse woodlands and to quantify errors in the estimates. The first sampling phase involved measurement of auxiliary variables of living Androstachys johnsonii trees;in the second phase, we performed destructive biomass measurements on a randomly selected subset of trees from the first phase. The second-phase data were used to fit regression models to estimate below and aboveground biomass. These models were then applied to the first-phase data to estimate biomass stock. The estimated forest biomass and carbon stocks were 167.05 and 82.73 Mg·ha-1, respectively. The percent error resulting from plot selection and allometric equations for whole tree biomass stock was 4.55% and 1.53%, respectively, yielding a total error of 4.80%. Among individual variables in the first sampling phase, diameter at breast height (DBH) measurement was the largest source of error, and tree-height estimates contributed substantially to the error. Almost none of the error was attributable to plot variability. For the second sampling phase, DBH measurements were the largest source of error, followed by height measurements and stem-wood density estimates. Of the total error (as total variance) of the sampling process, 90% was attributed to plot selection and 10% to the allometric biomass model. The total error of our measurements was very low, which indicated that the two-phase sampling approach and sample size were effective for capturing and predicting biomass of this forest type.
文摘In Daloa,the waters from wells and springs from shallow aquifers are used for drinking,given the low water coverage and organoleptic quality of water from the public network.However,the lack of an adequate sewage system and human activities could lead to a risk of chemical contamination of this water table.Yet,the vulnerability and contamination of groundwater in urban areas are a major concern that requires greater attention.It therefore seems necessary to map the specific vulnerability linked to chromium in order to identify the areas requiring special attention.To do this,we opted for Multi-Criteria Analysis,which takes many parameters into account and is suitable for porous media.This method is based on a numerical rating system,which takes into account hydrogeological,human and pollutant characteristics.Field data,laboratory data and maps were used.Using ArcGis software,the data was interpolated,reclassified and rated.The combination of maps indicates three classes of vulnerability:average(0.79%),high(97.53%)and very high(1.68%),with satisfactory validation criteria(coincidence rate:78.26%and margin of error 0.68%).Consequently,there is a potential risk of contamination of alterite aquifers throughout the city.The MCA has produced satisfactory results,but these can be supplemented by a numerical mass transport model to validate the degree of vulnerability.
