Optimum germination temperature for pinyon seed is about 21° C (70° F). Germination is epigeal (68). Preliminary studies indicate that germination can be significantly improved by washing seeds for 48 hours in running tap water. Cold stratification for 30 or 60 days increases speed of germination but not the percentage. Treatment with hydrogen peroxide to suppress mold and enhance germination generally is not effective. Seeds germinate in spring and summer following dispersal, depending on soil moisture and temperature, with summer germination coinciding with the onset of the rainy season. Also, seedling establishment probably depends on an adequate moisture supply during the first summer (29,30,54,66,68). Growth throughout the seedling stage is extremely slow, often with only primary needles developing the first year, and subsequent height growth averaging 2.5 to 5.0 cm (1 to 2 in) per year (67).
- Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965). U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp. http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm
No one has provided updates yet.