This distri- 
bland 
shrubs are 
eath the 
| there is 
| to three 
pronounced 
| shrubs 
Quercus 
hus sp. 
| the under- 
he grassland. 
a scrubby 
number of 
introduced 
result, the 
of native 
troduced 
ine grass- 
annuals. 
] 
| over 
The two 
uite differ- 
| brown, 
nd the oaks 
lands were 
growing, and 
dland as 
n-serpentine 
t is also 
e interior 
| form a 
etween the 
asslands 
At the 
| carpeted 
from the 
lowering 
were extracted 
pwise 
ata for the 
hat makes 
Table 2. 
infrared 
ating the 
    
  
  
two types. The classification accuracy was approximately 807%. In the April 
imagery a classification accuracy of 1007 was reached with the red channel. 
The red radiation was being strongly absorbed by chlorophyll pigments in the 
non-serpentine grassland, whereas the red radiation was strongly reflected 
by the carpet of yellow goldfield flowers on the serpentine. This phenomenon 
is short lived as the goldfields are only in bloom for a period of three weeks. 
SIERRA NEVADA FOOTHILLS STUDY AREA 
The Sierra Nevada foothills study area is located 160 km east of 
San Francisco in Calaveras and Tuolumne Counties. This area is physically 
similar to Jasper Ridge. Elevations range from 300 to 600 meters. Annual 
precipitation averages about 60 cm, coming mostly as winter rain. Winters 
are somewhat cooler than on Jasper Ridge and are similar in temperature to 
the southwest Oregon study area. The vegetation consists of a mosaic of 
grassland and oak-woodland of varying density, and chaparral. 
Image Analysis 
High altitude airborne scanner imagery was acquired over the Sierra 
Nevada foothills study area on April 23, 1982. The imagery is similar in 
configuration to the April imagery acquired over Jasper Ridge (Table 1). The 
vegetation in the foothills on this date was near its peak of green biomass, 
similar to the conditions on Jasper Ridge. 
The study area consists of Jurassic-Triassic metavolcanics, Upper 
Jurassic metasediments, undifferentiated Mesozoic ultramafic intrusives 
(primarily serpentinized), and the Pliocene Table Mountain andesite (Jenkins, 
1966; Clark and Lydon, 1962; Taliaferro and Solari, 1948). The metasediments 
and metavolcanics are covered by oak woodland and grassland. Figure 3 
illustrates the vegetation on a typical metavolcanic area. Serpentine areas 
are covered by an open Ceanothus sp. chaparral with scattered digger pine 
(P. sabiniana) (see Figure 4). The ground between the Ceanothus sp. individuals 
is sparsely covered by the same annual plants occurring on the serpentine 
grasslands on Jasper Ridge. Monkeyflower (Mimulus cutatus) is abundant along 
streams and moist drainages. The Table Mountain andesite is covered by a 
sparse grassland cover with widely scattered digger pine. The species present 
in the andesite grassland are similar to those located on the nearby serpentine. 
The scanner imagery was processed to form a false color composite 
for use in the field. On the false color composite (FCC), the non-serpentine 
grasslands and oak woodlands are represented by various shades of red. The 
serpentine areas, however, are brown. Although the andesite has a similar 
color, it is distinguishable from the serpentine. The major serpentine areas 
are represented on the imagery in a brown color, indicative of its scrubby. 
vegetation; an area mapped as serpentine (Jenkins, 1966; Taliaferro and Solari, 
1948) appeared to have a denser vegetation not characteristic of serpentine. 
When the area was field checked, it was found that this second area was covered 
with oak-woodland and grassland. Rock outcrops, sampled in the area, were 
found to be metavolcanic greestones with plagioclase phenocrysts. The area 
was apparently mismapped by Taliaferro and Solari (1948). Other maps continued 
the error. 
REFERENCES 
Brooks, R. R. 1972. Geobotany and Biogeochemistry in Mineral Exploration. 
New York, Harper and Row, 290p. 
Clark, W. B. and P, A. Lydon. 1962. Mines ‘and Mineral Resources of Calaveras 
County, Calif.: County Rept. 2, Calif. Div. of Mines and Geol., San Francisco. 
159