Biology ETDs
Publication Date
Spring 5-13-2023
Abstract
As wildfires increase in size and severity, large areas of forest are undergoing substantial increases in shrub cover. In forests where water is the limiting resource, the partitioning of soil water between shrubs and trees may determine how shrubs affect tree growth and water-stress. We analyzed the δ2H and δ18O values of xylem water for two conifer species (Abies concolor and Pinus jeffreyi) and two shrub species (Arctostaphylos patula and Ceanothus cordulatus) to assess how shrub cover affects the water-uptake patterns of conifers in the southern Sierra Nevada. We found that growing environment did not have a significant effect on the water source dynamics of either tree species, with similar source water contributions calculated for conifers growing in both the presence and absence of shrubs. Using a tree-ring analysis of growth and δ13C, we found a positive effect of shrub cover on tree growth and intrinsic water-use efficiency. Overall, our results demonstrate that shrub cover does not alter the water uptake patterns of nearby conifers and instead may have a positive effect on tree growth and water-use efficiency during both wet and dry years.
Project Sponsors
California Department of Forestry and Fire Protection as part of the California Climate Investments Program
Language
English
Keywords
Shrub Cover, Competition, Stable Isotopes, Water Source, Intrinsic Water-Use Efficiency, Sierra Nevada
Document Type
Thesis
Degree Name
Biology
Level of Degree
Masters
Department Name
UNM Biology Department
First Committee Member (Chair)
Matthew D. Hurteau
Second Committee Member
Seth D. Newsome
Third Committee Member
William T. Pockman
Recommended Citation
Goodwin, Marissa. "The effect of shrub cover on conifer water-use patterns, growth, and response to climate change in the southern Sierra Nevada." (2023). https://digitalrepository.unm.edu/biol_etds/458
