Glaciers
You are following the tracks of glaciers.
Most of the land around you was
covered with ice as recently as
10,000 years ago. The ice rounded
the shoulders of the peaks, carved
today's lake basins, polished the
remaining bedrock, and left
rounded rocks called erratics across
the high country. Soils have not had
much time to form, so the work of
the glaciers can be clearly seen in
large areas of bare granite.
Mountain Ecosystems
In the alpine Zone, just a few people acting
thoughtlessly can destroy a hundred years of growth.
Life is tough more than 9,000 feet
above sea level. The growing season
is short, little rain falls, soils are thin,
and it is often cold and windy. Alpine
plants have a narrow margin of
survival in this conditions; they are
more vulnerable to human disturbance,
and are slower to recover from
impacts than at lower elevations.
Please do not build campfires and
take special care to avoid trampling.
Evolution of trails
Yosemite's trails are a legacy of many generations.
The Native American residents of the
Sierra followed deer and bear trails as
they traveled these mountains. Later,
cattle and sheep herders used many
of the same trails to reach meadows
where they grazed their
animals. The cavalry often chased
illegal herders while patrolling,
mapping and exploring the backcountry
in the earliest days of the national
park. Vistiors today use these
same routes, improved and
expanded into a trail
system of more the 750
miles.
