Last updated: September 20, 2023
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Burnwood Trail Stop 2: Defining Old-Growth
Old-Growth Forest Hike Stop 2 - Defining Old-Growth
What determines old-growth? Generally, old-growth forests are considered primary forests, or forests that haven’t been cleared by humans and natural processes have been allowed to shape the ecosystem. A forest that has had major human clearing is referred to as a secondary forest, highlighting that the second forest has grown to replace the original that was cleared. However, some forests naturally don’t reach old-growth age due to frequent disturbances that naturally keep the ecosystem young.
In the New River Gorge, riverscour prairies naturally have frequent flooding that keeps vegetation from reaching old age. A riverscour prairie could theoretically be a primary ecosystem that humans haven’t disturbed, but it isn’t old-growth since flooding naturally keeps most of the species from achieving old age. A forest could also have been cleared by humans 200 years ago and enough time has passed to where old-growth features are coming back, but this wouldn’t be considered a primary forest due to the history of human clearing. A 200-year-old forest in the eastern United States could be considered old-growth, but a 200-year-old forest may not classify as old-growth in the Pacific Northwest where trees can live for over 1,000 years.
Despite all the subjectivity surrounding the definition of old-growth, there are many features that are unique to old-growth deciduous forests that can be scientifically measured and classified.