Abundant rain and mild winters create the perfect environment for trees such as Douglas firs and cedar to grow very large and very old. These trees were so big that after loggers carved the first undercut wedge out of one of the old giants, a dozen or more timber workers could crowd into the gaping cut and pose for a picture. Early settlers would sometimes build roofs over hollow stumps to make homes out of them. Old-growth forests are characterized by a mixture of old and new, large and small, living and dead all part of a dynamic ecosystem that is growing, evolving and continually changing. Even after a tree dies from old age or disease it is still a vital part of the ancient forest ecosystem.
Snags provide homes for dozens of birds and mammals.
When the snag falls over, the log becomes a haven for insects and many other animals. The downed log slowly decomposes and returns nutrients to the soil. However, old-growth forests are not defined solely by trees. Complex symbiotic relationships develop over centuries between all of the organisms present in the old-growth ecosystem. When ancient forests are cut, it takes many years to rebuild all of the severed connections.