Download or read book Effect of Vacuum Pumping on Lateral Movement of Sap in the Maple Tree Bole written by Barton M. Blum and published by . This book was released on 1968 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: S2Our recent studies of maple sap production have shown that invented tubing collection systems yield more sap than vented tubing systems, and that these increases are related to natural vacuum that develops in the unvented systems. Application of additional vacuum with a vacuum pump produced a further increase in sap yield. In these studies we used a paired-taphole type of experimental design. Two tapholes were drilled 6 inches apart on the same tree; one taphole of each pair received one treatment (vacuum) while the other was a control (no vacuum).S3.