Image from the Biodiversity Heritage Library.
Contributed by Harvard University Botany Libraries.
| www.biodiversitylibrary.org
Transcription
Physiography = nature of the earth's crust.
Annuals reproducing entirely by seed, most
of necessity start in bare ground (level of)
competition.
The Pined - dries community seems to
be the culmination of the succession set
around 9 to 10 thousand feet in the W. Rockies.
North of Camp a secondary succession is
in progress.
On bare rocks lichen are the pioneer
community. They break up rocks in two
ways:
1. Dissolution with organic acids
2. Mechanically by contraction when wetted,