Growth and production of a short rotation coppice culture of poplar. III. Second rotation results

This study describes production and growth of the second rotation of 17 poplar (Populus spp.) clones in a short rotation coppice culture (SRC). In addition, the link with leaf characteristics was studied. In April 1996, an experimental field plantation with 10,000 cuttings ha−1 was established on a former waste disposal site. In December 1996, January 2001 and February 2004, all stools were coppiced. At the end of the second rotation (2001–2003), highest biomass production was found for P. nigra clone Wolterson with 9.7 Mg ha−1 y−1. The best performers of the first rotation, i.e. P. trichocarpa×P. deltoides clones Hoogvorst and Hazendans, performed poorly in the second rotation, due to heavy rust infections. Two growth strategies were evident: Wolterson had a slow elimination of smaller shoots and had lots of smaller leaves; Hazendans and Hoogvorst had a rapid elimination of smaller shoots and had fewer, larger leaves. We conclude that shoot growth dynamics and leaf size were not the primary production determinants in our poplar SRC. But Melampsora larici-populina remained an important external determinant of biomass production.