Retention of leaf litter in streams from riparian plantings in southern Ontario, Canada

This study examines the short-term leaf litter retention from three tree species used in rehabilitative streamside plantings at Washington Creek, southern Ontario, Canada. The number of leaves retained under different riparian conditions (wide tree buffer, meandering; narrow tree buffer, meandering; narrow tree buffer, channelized) differed significantly (P < 0.05). This indicates that buffer width may not play a major role in organic matter retention and that stream morphology may be of greater importance. The largest proportion of leaves were retained within the first 10 m in meandering riparian conditions, whereas leaves were transported for 30 m before becoming retained under channelized riparian conditions. A greater number of silver maple (Acer saccharinum L.) leaves were retained compared to poplar (Populus spp.). However, no significant difference in the number of leaves retained was found between Populus spp. and Alnus spp., likely a function of leaf morphology. The relative proportion of leaves retained on various physical structures within the stream was found to be: rocks > streambank > debris dams > roots > wood. Results from this study may aid in the design of riparian plantings within the scope of agroforestry systems.