Reexamination of Effects of Paraformaldehyde on Tissues Around Tapholes in SugarMaple Trees

摘要

Pellets containing paraformaldehyde (PFA) are sometimes placed behind spouts intapped sugar maples to prolong sapflow and increase the yield of sap used to make maple syrup. The practice is controversial because the chemical has been shown to promote decay and is reported to cause cambial dieback around tapholes. This study reexamined the effects of EPA on tapped sugar maple and determined how these effects also are influenced by time of tapping and spout removal, and by taphole flushing. A survey of sugarbushes in Wisconsin revealed no relationship between PFA use and cambial dieback and rate of taphole closure. Other factors including poor tapping techniques and practices, drought, and old age affected these taphole attributes more than PFA.