Cone production may begin at an age of 20 to 30 years. Each cone can produce up to 400 seeds, but the percentage of viable seed ranges from 6.3 to 35 percent. Preferred methods of cone collecting include extension poles with appropriate pruners. Cones should be collected between mid and late August or just prior to disintegration. They should be stored in well-ventilated bags or sacks at temperatures between 70 and 80 degrees until the cones have disintegrated. Seeds can be extracted mechanically by using screens and then cold-stratified under dry conditions at temperatures between 10 and 30 degrees F for 4 to 6 months. Germination is best accomplished by placing them in a moist, well-aerated soil mix at temperatures between 35 and 40 degrees F. Light enhances germination and development of seedlings. Plant can be grown either individually in containers or in flats prior to transplantation. Under field conditions, seed should be sown in the spring at a density of 62.5 to 125 per acre and approximately 0.25 inches deep. During the first few years, growth ranges from 4 to 16 inches annually. Fertilizer combined with thinning enhances growth.