[Note: “How does one recognize an old-growth forest in the Adirondacks?” was written by Robert “Bob” Leverett of Native Tree Society, and appears on this blog with permission. Thanks to the Old-Growth Forest Network for sharing this fact sheet. Thanks also to Rob Leverett for sharing his illustrations. If you want to learn more about local old-growth read next: “Finding Original Forest” by John Davis.]

a. Old-growth forests have larger, older trees on the average than their regrowth counterparts. This is a no-brainer, but inexperienced woods walkers may not recognize the signs of advanced age, and size is relative. Nonetheless, areas in the Dacks with noticeably larger trees may be old growth.

b. Despite their name, old-growth forests are multi-aged, especially when encompassing larger tracts of woodlands. Natural processes are always causing tree falls. New trees sprout in the gaps. With gaps of varying size, different species may exploit the openings. The result is a mosaic of age classes that is not easy for a non-ecologist to recognize.

c. The structure of old growth from forest floor to the top of the canopy is more complex than that of younger forests. New forests are usually fairly uniform in age and size. One tree of a species looks pretty much like the next. As time goes on and individual trees die, new ones sprout, and old ones keeping getting older, the appearance of the forest from floor to canopy gets increasingly more complex. From this structural complexity, we get many more specialized habitats for plants and animals. The disheveled appearance is not always satisfying to the eye that seeks order, regularity. But survivability grows out of the greater complexity.

d. The floor of an Adirondack old-growth forest is uneven because of the pits and mounds left by falling trees. This is called pit and mound micro-topography. Species like yellow birch, sugar maple, American beech, and eastern hemlock have strong root systems. When large trees of those species blown down, the hole they leave can be huge. The upturned root mass eventually decays into a lump and the hole partially fills with sediment, but not entirely. The result is an undulating forest floor.

e. There are noticeable gaps in the canopy where trees have fallen. It is in these gaps that light-demanding species regenerate. In places where fires, derechos, tornados, or hurricanes level large areas of forest, regeneration can be even-aged, but the norm in the Dacks is many smaller events – single and multiple tree falls leaving gaps of varying size. The 1995 derecho was a notable exception.

f. In intact old-growth areas, there is a lack of invasive species that often colonize logged areas. Old growth areas are more resistant to invasion by alien plants because the native species have a firm hold. When an area is cleared and the ground layer of native plants and the underground network of supporting fungi greatly disturbed, the scene is set for invasives to replace native plants. It is common to see vine invasives choking trees along road corridors in urban areas.

g. Old growth forests exhibit an absence of signs of past human land use. Obviously, if one encounters old rock walls, apple trees, cellar holes, etc., humans changed the natural order. It can’t be old growth in such places.

h. The soils in an old-growth forest will be deeper and richer than those of younger forests that have regrown from logging, farming, or pasturing. This is an area of scientific investigation that is still in its infancy, but one can readily see the difference in soils and plant cover in areas that were heavily disturbed by human activity.

i. There will be many more moss, lichens, liverworts, and fungi in old growth. As a consequence, old growth soils hold more water. The abundance of plants that grow on logs, stumps, etc. increases dramatically in the old growth and the result is a greater amount of moisture retained at ground level. This helps to make old growth areas resistant to fire in the Adirondacks, a fact that is seldom understood by interests looking for reasons to harvest after blow-downs.

j. Old-growth forests usually exhibit downed logs randomly distributed and in all stages of decay. Old stumps and logs leave their remains as mounds. Since the continuation of small disturbances results in tree falls where the direction of fall is random, we see the result as a chaotic pattern of logs in all stages of decay.

k. As mentioned in a. above, old growth exhibits larger trees. However, the older trees are not just expanded versions of their younger selves. The young trees tend to be symmetrical in shape. But with age and external pressures, the form becomes asymmetrical and proportions change. Limbs thicken and contort. The amount of wood in the canopy becomes visibly greater. As a consequence, one can often look up on a ridge and quickly spot the older trees just by the shapes of crowns and thickness of the upper limbs.

If you think you know the location of an old-growth forest…

On public land…

Make sure it has been recognized as such (by contacting the ownership entity). Also stay alert to threats to the forest and make them known to the Old-Growth Forest Network and other local organizations such as the Adirondack Council. If the forest is not protected in perpetuity work toward making that happen.

On private land…

If it is your property do not be encouraged to log for any reason (“health of the forest”, 480a, $, etc). Consider selling or gifting the property to the state or a conservation organization (like Northeast Wilderness Trust or the Eddy Foundation or the Nature Conservancy or CATS with stipulations for its protection.) If this is not possible consider selling or donating a “forever wild” easement to one of the organizations above. You will still own the land and reap tax benefits.

If it is not your property make sure the owners know that they are caretakers to a very, very special place. Consider buying the land if they are willing to sell. Or try to broker a deal for a sale to the state or conservation organization.

Contacts:

• Old-Growth Forest Network, www.oldgrowthforest.net; 410-251-1800
• Northeast Wilderness Trust, www.newildernesstrust.org; 802-224-1000
• Eddy Foundation, www.theeddy.org; 518-962-4762
• Champlain Area Trails, www.ChamplainAreaTrails.com; 518-962-2287
• Adirondack Council, www.adirondackcouncil.org; 877-873-2240
• Native Tree Society, www.NativeTreeSociety.org