Observational Study of Sycamore Regeneration at two sites in Santa Clara County after the 2016-2017 Water Year

This memo serves as an update to the Sycamore Alluvial Woodland Habitat Mapping and Regeneration Study (Beagle et al. 2017), and describes changes seen at the two study sites, Upper Coyote Creek and Pacheco Creek, between fall 2015 and fall 2017. We were tasked with augmenting tree core data as reported in 2017 by adding additional trees to further investigate the relationship between sycamore establishment and geomorphic position, which partially serves as a proxy for the role flood processes play in improving the suitability of conditions for sycamore seedling establishment and growth. Coincidentally, major flooding during water year 2016-2017 provided us with an exciting opportunity to observe sycamore regeneration at these two study sites. This memo reports on tree coring results; documents and maps sycamore seedlings and other observed regeneration strategies of sycamores during 2018 related to geomorphic change at the two study sites; proposes natural and anthropogenic drivers of sycamore regeneration; and outlines next steps for further investigation.