The biodiversity quality of ground-layer invertebrates within the cropped area of a plantation of the biomass crop willow short-rotation coppice (SRC) grown within a floodplain was compared to the biodiversity quality...The biodiversity quality of ground-layer invertebrates within the cropped area of a plantation of the biomass crop willow short-rotation coppice (SRC) grown within a floodplain was compared to the biodiversity quality of the neighbouring plots of floodplain grassland and a mixed deciduous woodland plantation. Pitfall traps were used to collect ground beetles (Carabidae) and arachnids (Araneae and Opiliones) in the plots over a period of two years. A range of biodiversity indices was used to assess the biodiversity quality of each of the three plots, and the willow SRC was compared to each of the controls using Mann-Whitney tests. The willow SRC transitioned from almost bare ground to young woodland during the two years of the study, which affected comparisons with alternative land uses as the habitat during the second year was very different from the habitat at the start of the study. Compared to plantation woodland, in the first year, the effect was mostly positive, but this declined in the second year. Compared to grassland there was a largely negative effect in both years. However, when in combination with other habitats, willow SRC cultivation on floodplain land may have an overall positive effect on invertebrate biodiversity quality.展开更多
To meet the need for effective management of poplar(Populus spp.)plantations in Sweden regarding different assortments,two equations were developed to estimate commercial stem volume for either any given top diameter ...To meet the need for effective management of poplar(Populus spp.)plantations in Sweden regarding different assortments,two equations were developed to estimate commercial stem volume for either any given top diameter or any stem fraction length.Data for fitting the equations came from 112 trees in 42 stands on farmland.Mean stand age,density and diameter at breast height(DBH)was 15.5 years,980 stems/ha,and 24.2 cm,respectively.Independent variables are for Eq.(1):DBH,total stem height(H)and given stem length fraction(h).For Eq.(2);DBH,H and given top diameter(d).Eq.(2)based on top diameter performed better than Eq.(1)based on stem length fraction with R2 of 0.994 and 0.991 respectively,and with Absolute Bias(AB)of 0.041 and 0.047(m3)respectively.The presented equations can be used to optimise the efficiency and profitability of poplar plantations when harvesting trees with larger diameters,for additional timber assortments other than bioenergy.展开更多
文摘The biodiversity quality of ground-layer invertebrates within the cropped area of a plantation of the biomass crop willow short-rotation coppice (SRC) grown within a floodplain was compared to the biodiversity quality of the neighbouring plots of floodplain grassland and a mixed deciduous woodland plantation. Pitfall traps were used to collect ground beetles (Carabidae) and arachnids (Araneae and Opiliones) in the plots over a period of two years. A range of biodiversity indices was used to assess the biodiversity quality of each of the three plots, and the willow SRC was compared to each of the controls using Mann-Whitney tests. The willow SRC transitioned from almost bare ground to young woodland during the two years of the study, which affected comparisons with alternative land uses as the habitat during the second year was very different from the habitat at the start of the study. Compared to plantation woodland, in the first year, the effect was mostly positive, but this declined in the second year. Compared to grassland there was a largely negative effect in both years. However, when in combination with other habitats, willow SRC cultivation on floodplain land may have an overall positive effect on invertebrate biodiversity quality.
文摘To meet the need for effective management of poplar(Populus spp.)plantations in Sweden regarding different assortments,two equations were developed to estimate commercial stem volume for either any given top diameter or any stem fraction length.Data for fitting the equations came from 112 trees in 42 stands on farmland.Mean stand age,density and diameter at breast height(DBH)was 15.5 years,980 stems/ha,and 24.2 cm,respectively.Independent variables are for Eq.(1):DBH,total stem height(H)and given stem length fraction(h).For Eq.(2);DBH,H and given top diameter(d).Eq.(2)based on top diameter performed better than Eq.(1)based on stem length fraction with R2 of 0.994 and 0.991 respectively,and with Absolute Bias(AB)of 0.041 and 0.047(m3)respectively.The presented equations can be used to optimise the efficiency and profitability of poplar plantations when harvesting trees with larger diameters,for additional timber assortments other than bioenergy.
