Summary: J. Range Manage.
47:151-154, March 1994
The effect of Quercus douglasii
understory yield and composition
J.W. BARTOLOME, B.H. ALLEN-DIAZ, AND W.D. TIETJE
Authors are professor, associate professor, and specialist, Department of Environmental Science, Policy, and
Management, University of California, Berkeley 94720.
The canopy of Quercus douglasii I-I.& A. (blue oak) has been
variously reported to enhance or suppress understory production.
The effects of canopy removal have been reported only for the
northern portion of blue oak's range. We removed all blue oaks
from 6 plots in the central coast of California and found no
significant change in understory biomass over 3 years. Understory
herb cover averaged 32.6% on cleared plots, compared to 24.3% on
uncut plots, but composition changed little with the exception of
an increase in Erodium cicufarium (L.) L'Her. Clearing did not
produce the distinctive species composition and forage enhance-
ment under Q. doughsiicanopy reported in other studies, all based