NON-DESTRUCTIVE SAMPLING FOR YIELD ESTIMATION

AIMThemostcommonmethodforas-sessingtotalbiomassisbydestructive1ysampling,i.e.cuttingdownrandomsam-ples,weighingthem,andextrapo1atingtheresultsfortheentirep1antation.Theesti-matewi1lgenerallybemoreaccuratewithalargersample,butenteringa3-5yearo1dplantationtocutdownshootsanddragthemouttobeweighed,isatime-con-sumingbusiness.Itisthereforenecessarytofindsomereliab1emeansofestimatingbiomassfromparameterswhichcanbeeas-ilymeasuredwhi1etheshootsarestillstanding.Amodelneedstobecreatedtoassessbiomassfirs…

Non-destructive sampling for yield estimation

A general model was sought to estimate the shoot biomass of short rotation coppice crops in the UK. Differen agrd shoots of willow and poplar cloncs were sampled from different sites to produce 19 data sets. Modcls wcrc created for each clone, scparatcly for 1 -, 2-and 4-year old willow, and general models for 1 to 4 year willows. and 3 year old poplars. The models were compared with regard to accuracy and correlation coefficient. The diameter at breast height was chosen as the best independent variable to estimate the shoot weight. A general multiplicative model without intercept was created for all the willows and poplars sampled. The model was evaluated and was found to have average accuracy of 92% when tested with new data from 1 -and 3-year old willow clones. The model requires further validation.