Blue Oak Restoration-2003

Principal Investigator : Jeremy James

Blue oak (Quercus douglasii) is one of the most widespread oak species in the lower elevation sierra foothill and coast range, providing critical habitat for numerous species and representing an important functional group in theses systems. Typical of many long lived, slow growing species, seed production (acorns) and seedling recruitment are episodic and sparse and extensive changes to how we manage these systems (e.g. introduction of non-native annual grasses, grazing, fire) have lead to wide spread concerns that recruitment and survival of new individuals may not be adequate to keep up with mortality of older trees.

The broad objective of this research project is to examine how plant stage (seedling, sapling, juvenile), soil moisture and management (competing native, non-native plants) influence growth and survival.

To do this we will plant large populations of acorns and seedlings (density of 150 individual per ha) and exposed these populations to different environmental conditions (soil moisture, presence/absence of competing neighbor plants) and management (with or without tree shelters). During key parts of the growing season we will make measures of plant growth, survival and predawn water potential) and will track these responses over the coming decade. Some of these questions have been examined on a short-term time scale.

The goal with this project is to establish long term plots that allow us to track theses population dynamics over multiple decades. If successful, this research will fill an important gap between detailed short-term research and long term observational work, providing important population level data for time periods especially important for Blue oak recruitment.