Nc. Vance et Ja. Entry, Soil properties important to the restoration of a Shasta red fir barrens in the Siskiyou Mountains, FOREST ECOL, 138(1-3), 2000, pp. 427-434
Because of past major disturbances, the highly erodible,granitic soil in a
Shasta red fir (Abies magnifica A. Murr. Var. shastensis) barrens located i
n McDonald basin on the north side of the Siskiyou Mountains crest is a maj
or contributor of sediment to the aquatic system. Soil erosion is accelerat
ed where vegetation is sparse and colonization slow, therefore, it is impor
tant that native plant cover be restored and the site rehabilitated. We exa
mined soil properties that may be associated with vegetation patterns in th
e barrens and adjacent Shasta red fir forest and would have application to
restoring native plant diversity and cover to the barrens. At a 40 ha study
area we investigated plant available nutrients, soil C, microbial biomass,
and enzymes involved in organic matter decomposition and nutrient cycling
in barrens and forest soils to determine if loss of the organic layer by er
osion affected soil chemistry and microbiology. Twelve samples each were co
llected from 0 to 10 cm soil depth in forest and barrens and analyzed for C
, N, P, K, Ca, Mg, Mn, Fe, Cu, B, Zn, Mo, and Al; microbial biomass, and de
hydrogenase, urease, and acid phosphatase activity. Soils supporting forest
vegetation contained higher concentrations of C, N, K, Ca, and Mg, indicat
ing differences between forest and barrens in important soil chemical prope
rties. Ca and Mg were extremely low in the barrens soil suggesting loss of
these nutrients by erosion where there is a lack of vegetation cover. Soil
organic matter was higher in forest than in barrens soil and was positively
correlated with soil N (r(2)=0.78), dehydrogenase (r(2)=0.65) and acid pho
sphatase activity (r(2)=0.50). Although microbial biomass was extremely low
, dehydrogenase and acid phosphatase activity were sensitive indicators of
differences in organic matter and microbial activity between forest and bar
rens soil. The study indicates that certain soil chemical and biological pr
operties may be useful in monitoring ecological change and helpful in under
standing vegetation patterns. Published by Elsevier Science B.V.