DENDROLOGY

Detailed explanation-1: -Virgin or first-growth forests are old-growth forests that have never been logged. The concept of diverse tree structure includes multi-layered canopies and canopy gaps, greatly varying tree heights and diameters, and diverse tree species and classes and sizes of woody debris.

Detailed explanation-2: -Tongass National Forest, Alaska Tongass National Forest is home to some of the oldest trees on earth-many of them dating back more than 800 years. Spruce, cedar and western hemlock trees stretch more than 200 feet into the sky and reach nearly 12 feet in diameter at chest level.

Detailed explanation-3: -Old growth encompasses the later stages of stand development that typically differ from younger stages in a variety of characteristics that may include tree size, accumulations of large dead woody material, number of canopy layers, species composition and ecosystem function.”