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): Richard P. Pharis
    Date: 1966
    Source: Ecology. 47(2): 211-221
    Publication Series: Scientific Journal (JRNL)
    PDF: View PDF  (2.4 MB)

    Description

    Whole plant lethal points of foliage moisture content (FMC) for ponderosa pine, sugar pine, Douglas-fir, grand fir, and incense-cedar were established from foliage tissue of various ages. Exact lethal level depended upon the age of the tissue, but there was a general plateau between the ages 6 and 13 months for sugar pine and Douglas-fir and 3 and 13 months for incense-cedar. Whole plant relative turgidity (RT) lethal points were set for the pines and firs using 13-month-old needles. Dry-weight loss upon soaking the needles was found to increase with the severity of the drought, especially for the firs. Soil moisture content (SMC) lethal points were established for all five species on builders' sand (death began at an SMC probably equivalent to tension above 24 atm) and on pumice soil (death points equivalent to tensions from 15 to 19 atm). Foliage moisture content declined with decreasing soil moisture stress in a straight-line relationship; FMC may be used as an index of soil moisture stress within a rather narrow range of SMC and may also be calibrated with leaf tissue diffusion pressure deficits developing under soil moisture stress to give an index of the water balance of the plant.
    Based on the SMC at the death point and also upon some species' ability to outlive others under competitive conditions, ponderosa pine, incense-cedar, and Douglas-fir were the most drought resistant, sugar pine the least, and grand fir intermediate. Ways are suggested in which the mixed conifer forests could become established and retain their mixed composition through maturity. The findings suggest that if planting is used to regenerate clearcuts, ponderosa pine and incense-cedar would be first choice, but that sugar pine would also be a preferred species if seeding is used.

    Publication Notes

    • You may send email to pnw_pnwpubs@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

    Pharis, Richard P. 1966. Comparative drought resistance of five conifers and foliage moisture content as a viability index. Ecology. 47(2): 211-221

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/27047