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An index of ripeness for sugar pine seed

Informally Refereed
Download (PDF 585 KB): https://research.fs.usda.gov/download/treesearch/40996.pdf

Abstract

Immature or unripe seed may be one cause of the poor germination of sugar pine occasionally experienced in nursery practice or direct seeding projects. Ripeness of pine seed, or the time to harvest cones, is usually judged by a change from green to brown in the color of cones or by the development of a firm consistency in the endosperm. However accurately these criteria may be applied, they are subjective and cannot be described well enough to permit consistency in their use. This paper describes an index of ripeness for sugar pine seed.

Citation

Fowells, H.A. 1949. An index of ripeness for sugar pine seed. Res. Note 64. Berkeley, CA: U.S. Department of Agriculture, Forest Service, California Forest and Range Experiment Station. 5 p.