The effect of seed size variation in Quercus pacifica on seedling establishment and growth

Abstract

Quercus pacifica, the island scrub-oak, is the dominant species in oak chaparral on the three largest California Channel Islands. While the population on Santa Cruz Island has experienced a strong recovery, the populations on Santa Rosa and Santa Catalina islands are of conservation concern, and managers are actively restoring oak habitat by planting acorns. Previous work shows that acorn size, a factor that is known to affect planting success, varies significantly across the range of the species. To determine whether acorn size in Q. pacifica affects early seedling growth, I planted over 600 acorns from Santa Cruz Island in a greenhouse. Our results show that larger acorns are more likely to germinate, and that acorn mass had strong effects on root mass, shoot mass, seedling height and leaf surface area. Assuming that acorn size may have a similar effect on Santa Rosa and Santa Catalina, I suggest that managers plant larger acorns to maximize the effect of restoration efforts.

Parent Publication

• Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world

Citation

Pesendorfer, Mario B. 2015. The effect of seed size variation in Quercus pacifica on seedling establishment and growth. In: Standiford, Richard B.; Purcell, Kathryn L., tech. cords. Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world. Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 407-412.