Extended Data Fig. 3: Decision trees on the proportion of ring enlargement and thickening in European beech, silver birch, common aspen and pedunculate oak in temperate western Europe.
From: No winter halt in below-ground wood growth of four angiosperm deciduous tree species
The figure displays the proportion of ring enlargement (a) and thickening (b) across time and species for mature beech and birch trees from autumn 2020 to spring 2021 in Belgium. The proportion of ring enlargement (c) and thickening (d) across time and species for beech, birch, oak and aspen saplings from autumn 2017 to spring 2018 in Belgium. The proportion of ring enlargement (e) thickening (f) across time, species and country for saplings of beech and birch in autumn 2018 in Spain, Belgium and Norway. The table below each tree indicate the proportion of ring enlargement and thickening of the final branch determined by the regression tree (Tree) and with the GAM model prediction (GAM). DOY indicates day of year. DOYs larger than 325 indicate time periods expanding into the next spring.
