Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Michael F. Allen
    Date: 2015
    Source: Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 13-22
    Publication Series: General Technical Report (GTR)
    Station: Pacific Southwest Research Station
    PDF: Download Publication  (383.0 KB)

    Description

    Oaks are extremely resilient trees. They have persisted since the mid-Cretaceous, with life forms ranging from shrubs to large trees, from evergreen to deciduous. They have two distinct, but critical, adaptations to drought that make this "mesic" taxon adaptable to dry hot environments. First, they form both arbuscular and ectotrophic mycorrhizae, with a high diversity of fungi that independently evolved many times. This means that a single tree forms mycorrhizal symbioses with partners adapting to different conditions and accessing many different resources. Oaks also have deep roots. This allows access to water resources deep in the groundwater, and with hyphae that extend into the granite matrix. Thus, water can be accessed even during drought periods when surface soils are extremely dry. Fine roots and mycorrhizal hyphae persist utilizing hydraulically-lifted water, and can even take up nutrients during these extremely dry conditions. These mycorrhizal hyphae remain viable during drought periods allowing them to rapidly utilize surface precipitation from summer monsoonal events. Together, these adaptations should allow oaks to persist and even thrive under the projected climate change, unless conditions become too harsh. That remains a critical task of future research and monitoring.

    Publication Notes

    • You may send email to psw_communications@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Allen, Michael F. 2015. How oaks respond to water limitation. In: Standiford, Richard B.; Purcell, Kathryn L., tech. cords. Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world. Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 13-22.

    Keywords

    anthropocene, drought, mycorrhiza, nitrogen, nutrient, oak, root

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/49910