ALTITUDINALLY COORDINATED PATTERNS OF SOILS AND VEGETATION IN-THE SAN JACINTO MOUNTAINS, CALIFORNIA

Publisher Website
Google Scholar
Abstract
Soils and vegetation were sampled in eleven ecosystem types along the elevation gradient of 3000 m on the inland slope of the mountains, from subalpine and montane pine forest through woodlands and chaparral to desert. All soils were on granite or granite-derived materials, so that soil differences reflected effects of climate directly or by way of vegetation. Gradients of soils characteristics were observed: (1) Soil organic content increased with elevation, but soil litter cover was maximal at upper-middle elevations where plant cover and productivity were highest. (2) Other characteristics related to organic matter—water-holding capacity, and cation exchange capacity—increased with elevation; bulk density and particle density decreased with elevation. (3) Water movement shifted from moderate leaching at higher elevations, through relative balance, to the evaporative climate of the deserts and surface salinization in the lowest-elevation soil sampled, a solonchak. (4) Soil pH and percent base saturation decreased with increasing elevation. (5) Clay production was maximal in the combination of temperature and precipitation conditions of middle elevations. Although these are relatively young soils of mountain slopes, they suggest a geographic sequence from a cool (and relatively dry) northern woodland to a warm desert climate. Soils and vegetation were sampled in eleven ecosystem types along the elevation gradient of 3000 m on the inland slope of the mountains, from subalpine and montane pine forest through woodlands and chaparral to desert. All soils were on granite or granite-derived materials, so that soil differences reflected effects of climate directly or by way of vegetation. Gradients of soils characteristics were observed: (1) Soil organic content increased with elevation, but soil litter cover was maximal at upper-middle elevations where plant cover and productivity were highest. (2) Other characteristics related to organic matter—water-holding capacity, and cation exchange capacity—increased with elevation; bulk density and particle density decreased with elevation. (3) Water movement shifted from moderate leaching at higher elevations, through relative balance, to the evaporative climate of the deserts and surface salinization in the lowest-elevation soil sampled, a solonchak. (4) Soil pH and percent base saturation decreased with increasing elevation. (5) Clay production was maximal in the combination of temperature and precipitation conditions of middle elevations. Although these are relatively young soils of mountain slopes, they suggest a geographic sequence from a cool (and relatively dry) northern woodland to a warm desert climate. © Williams & Wilkins 1976. All Rights Reserved.

This publication has 0 references indexed in Scilit: