Legacy forests retain functional, biological, structural, and genetic "legacies" of indigenous or native forests.
Legacy forests are natural forests that retain biological, structural, functional, and/or genetic legacies of natural and old growth forests. Most legacy forests were selectively logged during the first half of the 20th Century. Prior to World War II, there were no chainsaws, and logging operations were very labor intensive. There were also a lot of big trees, so loggers would often leave behind the smaller trees, defective trees, standing dead trees, and trees that were difficult to access or out-of-reach of their yarding systems. In other cases, trees were left behind as seed trees.
Many of these forests closely resemble old growth. Because these forests were not re-planted, but instead allowed to grow back on their own, they exhibit much of the species diversity, genetic diversity, and structural complexity of the natural forests they replaced.
Because almost all of the old growth forests in Western Washington were logged long ago, legacy forests play a critical role in preserving the biological, genetic, and ecological legacies of the natural, lowland forests that once dominated the Pacific Northwest.