ABSTRACT

Dennis Baldocchi, Qi Chen, Xingyuan Chen, Siyan Ma, Gretchen Miller, Youngryel Ryu, Jingfeng Xiao, Rebecca Wenk, and John Battles

Oak trees and their savanna woodlands have played many important roles in the history, development, and ecology of California and the American West (Pavlik et al., 1991; Tyler et al., 2006). Starting with the Spanish Mission period till today, cattle have grazed the oak savanna, producing beef for our dinner, leather for our shoes, and tallow for our soap. In the mid-nineteenth century, 49’ers mined the oak savanna for gold and used its wood for cooking,

CONTENTS

Introduction ......................................................................................................... 135 Biogeography ....................................................................................................... 137 Structure and Function ....................................................................................... 138

Canopy Architecture ................................................................................. 138 Leaf and Tree Physiology .......................................................................... 138

Canopy Scale: Energy and Water Fluxes ......................................................... 141 Canopy Scale: Carbon Fluxes ............................................................................ 143 Discussion ............................................................................................................ 146 Acknowledgments .............................................................................................. 148 References ............................................................................................................. 148

heating, and building mine shafts. Today, the oak savanna provides many ecological services and benefits to the region. Oak savannas vegetate the watersheds of the many rivers stemming from the Sierra Nevada and Coastal mountain ranges. In doing so, they protect the soils of this hilly terrain and provide habitat for wildlife and acorns that have sustained the Native American population and wildlife for millennia. From a hydrologic perspective, runoff from these watersheds provides water for a large fraction of California’s multibillion dollar agricultural economy and its population of more than 35 million inhabitants.