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Effect of Vacuum Pumping on Lateral Movement of Sap in the Maple Tree Bole

出版	Northeastern Forest Experiment Station, Forest Service, U.S. Department of Agriculture, 1968
URL	http://books.google.com.hk/books?id=o-LLxaZpc2IC&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋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.