The study looked at how well a mix of different poplar and willow trees grown close together (short rotation coppice) did. They checked how much the trees grew above ground and their measurements over several years. By looking at this info, they found out how much the trees grew overall and how stable the growth was. Their results show that mixed poplar and willow short rotation coppice can give a good amount of biomass. They used statistics to make sense of the data and see the differences between the trees.