Effect of fertilizer on cone production of sugar pine

Abstract

Fertilizing seed trees may be one way to improve reforestation of cut-over and fire-destroyed timber stands in California. One of the chief difficulties in reforestation here is that most of the commercial conifers do not produce good crops of seed-bearing cones often enough. Heavy crops have been as much as 7 years apart. As a result an adequate supply of seed for natural regeneration seldom occurs at the right time on cut-over areas. If artificial regeneration is relied on for new timber crops, tree planters have to collect and store large quantities of seed during the few good years to tide them over the many poor ones. Heavier crops at shorter intervals would help solve a good many of these problems. That this objective may be reached through fertilization is shown by a preliminary test the Experiment Station recently completed with applications of ammonium phosphate around sugar pines.

Citation

Schubert, Gilbert H. 1956. Effect of fertilizer on cone production of sugar pine. Res. Note 116. Berkeley, CA: U.S. Department of Agriculture, Forest Service, California Forest and Range Experiment Station. 4 p.