In the late 1920s and early 1930s Albert Everett Wieslander and
several others, in a project of the newly formed California Forest
Experiment Station, explored much of California's wildland sampling
vegetation, taking photographs, collecting specimens, and drawing
exquisitely detailed maps of what they found. The marvelously preserved
collection is now known as the Wieslander Vegetation Type Mapping (VTM)
collection. The entire survey encompassed nearly seventy million acres of
the state, covering most of the wild areas excluding the deserts and the
larger agricultural areas. These data constitute an invaluable resource
for ecological studies. Our VTM Digitization Project is a collaborative
effort by teams at UC Berkeley and UC Davis and is funded by the US
Forest Service and USDA CSREES. The Project aims to digitize the entire
VTM collection for use in modern ecological and geospatial analysis and
to facilitate general data access and distribution.
The VTM collection consists of five main components:
1. Plot Data
About 13,000 sample plots were located in the central and southern
coastal ranges and in the Sierra across a gradient of vegetation types.
Records contain data on tree stand structure, percent cover of dominant
overstory, and understory vegetation by species, soil type, parent
material, leaf litter, and environmental elements for each site.
2. Plot Maps
The original plot locations were stamped in red ink on USGS topographic
maps that had been cut into sections, mounted on canvas, and folded to
facilitate use. The plot map collection comprises about 150 15-minute
(1:62500 scale) and 30-minute (1:125000 scale) U.S. Geological Survey
quadrangles (Figure 2 below). Unfortunately, the resulting maps were not
dimensionally stable and 80 years of use, temperature changes, and other
factors have warped many of the maps.
3. Vegetation Maps
Vegetation type maps showing hand drawn polygons of forest type and
associated species were drawn in the field by direct observation and by
"sketching from ridges, peaks, and other vantage points". Some areas have"zoomed-in" maps drawn on 6- and 7.5-minute USGS quads. The major
vegetation types were subdivided into pure and mixed stands with notation
on species composition and grouped by fire hazard characteristics, use,
or economic importance. There are about 350 of these detailed and
beautiful maps in the collection. Only some of these have previously been
published.
4. Photographs and Associated Data
There are approximately 3,100 black and white photographs taken during
1920-1941, with their photo points and floristic associates noted. In
addition there are approximately 100 topographic maps. The photographs
document the typical and atypical subtype, species, timber stand
conditions, range of variation, consequence of land use and cultivation,
grazing, logging, mining and fire. Wieslander was the main photographer
with a second series photographed by Richard C. Wilson (Class of 1934,
past Director, California Dept. Forestry and Fire Protection), C. Raymond
Clar (Class of 1927, past Chief Deputy State Forester), and others.
5. Herbarium Specimens
Herbarium specimens were collected for every species recorded on the
vegetation maps or in the sample plots. See Jepson Herbarium SMASCH Query Acquisistion Records
http://www.mip.berkeley.edu/www_apps/smasch/smasch_accession.html for more information. Many of the samples collected during the original VTM surveys now reside in the UC Berkeley Jepson Herbarium. This site allows you to search for them when you select 'Vegetation Type Map Project' from the 'Voucher' box.
See
vtm.berkeley.edu for more information