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Home → Publications → Tree Planters' Notes → Tree Planters' Notes Issue 17 (1954) → Specific Gravity as a Test for Cone Ripeness with Red Pine

Specific Gravity as a Test for Cone Ripeness with Red Pine

The use of the specific gravity test for determining the ripeness of pine cones has been described in forestry literature for several years. In order to make a local test with red pine, which is commonly collected in New York State, a test was made in 1952, using S. A. E. #20 Lubricating oil as a test liquid. The specific gravity of S.A.E. #20 is quoted with a value of .88. Using this as a test liquid when cones float they have a specific gravity of less than .88; and when they sink, the specific gravity is more than this amount. Cone collections were made at intervals on seven different occasions from July 30 to September 25, 1952. The specific dates are shown in the tables below.


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Author(s): E. J. Eliason, Joseph A. Hill

Publication: Tree Planters' Notes - Issue 17 (1954)