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Vacuum Pumping Increases Sap Yields from Sugar Maple Trees
Barton M. Blum
Melvin Ray Koelling
出版
Northeastern Forest Experiment Station, Forest Service, U.S. Department of Agriculture
, 1968
URL
http://books.google.com.hk/books?id=TSX-sL6F3yQC&hl=&source=gbs_api
EBook
FULL_PUBLIC_DOMAIN
註釋
S2In the spring of 1967, a vacuum pump was installed at a sugarbush located in Underhill, Vermont. This work proceeded in two phases: an individual-tree study designed to determine if sap could be drawn out of a tree in sufficient quantities to account for large yield differences; and a large-scale study of the effects of sustained levels of vacuum on yields from a nearly commercial-size network of tubing. S3.
