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Matt Ritter, Department of Biology, Cal Poly San Luis Obispo

Oaks are the most iconic and characteristic trees of California. Oak woodlands occur throughout much of the state, covering about ten percent of the land area. Most oak species native to the state occur primarily in the California Floristic Province and nowhere else. For millennia their acorns provided a primary food source for California’s Native Americans. There are 21 species native to California, 10 of which grow into stately trees, whereas the remaining 11 mature as multi-stemmed shrubs found in chaparral and arid woodlands of the southeastern deserts. California’s oaks range in size from small shrubs, barely knee high, to some of the most enormous oaks in the world: the canyon live oaks (Quercus chrysolepis) and valley oaks (Q. lobata). I will present the results of a recent California tree oak mapping project and define areas of unexpectedly high and low tree oak diversity in the state. I will also offer an update on the oak trees on the California Big Tree registry, some of which have been impacted by recent wildfires and climate change.