Growing-season stemflow production within a deciduous forest of southern Ontario

Stemflow production within a red oak (Quercus rubra L.)-sugar maple (Acer saccharum Marsh.) -American beech (Fagus grandifolia Ehrh.) dominated stand in southern Ontario was evaluated during the growing season of 1995. For events that produced stemflow from all sampled tree boles (rainfall >= 4.3 mm), the geometric mean Herwitz (Earth Surf. Process. Landforms 11 (1986) 401) tunnelling ratios were 7.3, 20.6, and 26.3 for oak, maple, and beech, respectively. Geometric mean funnelling ratios for these three species increased in a linear fashion with increasing rainfall depth for events ranging from 4.3 to 17.4 mm. However, funnelling ratios for the two larger rainfall events measured during the study (27.4 and 40.1 mm) were relatively small, suggesting that after a certain rainfall depth threshold has been reached, trees become less efficient at diverting intercepted rainfall to their holes. Significant (alpha = 0. 10) positive linear relationships were found between stemflow production (1/tree) and beech basal area for all rainfall events >= 2.2 rum, while for oak and maple such relationships corresponded with only some relatively large rainfall events. Possible causes for the discrepancies in the funnelling efficiencies of the three tree species and between relatively small and large events are provided. Copyright (c) 2006 John Wiley & Sons, Ltd.