Stem biomass yields at different planting designs and spacings in willow coppice systems

Stem biomass yields and stand closure, with different numbers of Salix plants per hectare and different distances between single rows and double rows, were assessed during the first cutting cycle of 5 years and into the first 2 years of the second cutting cycle. Stand closure was fastest with single row systems with 100 cm between the rows, while stands with 150 cm between rows needed much longer to close. Planting designs tested did not influence the stem biomass yield per hectare, although stool weight was affected, mostly due to distance and competition within the row. Biomass yield during the first cutting cycle was positively correlated with number of plants per hectare up to 2 x 10(4), but not above that. The results of this investigation indicate that plant design within certain limits could be adjusted, without losing yield potential, to the requirements of tractors and machines used in managing the Salix stand. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.