|Old-growth forests do
at least three very important things.
1. They provide homes for plants and
2. They teach us what natural, old forests are like.
3. They inspire us with glimpses of majesty and age.
1. Homes: Many plants and animals need old-growth forests
to survive. You may have heard of the spotted owl in the Northwest,
which requires standing dead trees for nesting. Some eastern birds
also show preferences for old-growth forests. For example, Blackburnian
warblers were found to be 45 times more common in an old-growth stand in
Pennsylvania than in neighboring secondary growth (R.Leverett, pers.comm.).
Salamanders that require moist environments thrive in the deep layer of
leaves and dead wood that accumulates in old-growth forests. Many
salamanders are more abundant in old-growth forest (Meier et al. 1996).
|Certain lichens and mosses also require very moist environments with lots of rotting wood. 70 species of lichens were found to grow almost exclusively in old-growth (Selva, 1996). 24 species of bryophytes were only found growing in old-growth stands (Cooper-Ellis 1994). Picture:L.Orrell.||
|You may associate wildflowers with open meadows, but they also grow in the forest. Spring woodland flowers show a preference for old-growth forests (Duffy and Meier 1992). These flowers are known as spring ephemerals because they may wither away after a few weeks in the spring. They like old-growth because they do their growing and flowering before the trees leaf out, which gives them an edge in the deep shade of an old forest. The plant on the left is a baneberry (not a spring ephemeral), growing in old-growth. There are other species of animals, plants and fungi that need old-growth forests, too. More study is needed in this area. Picture:L.Orrell.|
Why do certain plants and animals need old-growth forests? Old
forests have several characteristics that young forests do not, including
snags, dead wood, deep litter, pits and mounds and different ages of trees.
|Snags: Trees get sick and die, or their tops are snapped off in a windstorm. This creates snags, standing dead trees that are great homes for many birds and other animals. They are also good sources of food for insects and their predators. For more on snags and to see some more, check out this site.||
|Pits and mounds: When trees fall over in a windstorm, their roots may be pulled from the ground, leaving a huge pit. As the roots decay, they merge with the soil attached to them, forming a mound. When forests are logged or cleared for agriculture, the forest floor tends to get leveled by heavy equipment, dragging, trampling, and plowing, erasing any pits and mounds. Pits and mounds differ in their soil types, moisture and temperature from the rest of the forest. Certain plants specialize on pits and mounds, which are much less common in younger forests. Picture:L.Orrell.|
2. Classrooms: Old-growth forests are unique classrooms. In New England, much of the forest was cleared for agriculture in the 1800s. This land has since grown back to forest (called secondary forest), but it has been changed forever by being farmed. The soils in these forests may be very different, lacking the diverse fungal community and rich nutrient store found in many old-growth forests. They may be missing plants and animals which will take many, many years to return to them. Some people think that secondary forests have lost some of the genetic diversity that is found in old-growth forests. They think that trees in and around old-growth forests may be growing faster and bigger than in secondary forests.
We will never know what long term impact we have had on our forests
unless we have a baseline for comparison. Studying old-growth forests
can teach us what forests are like when they have been less disturbed by
people. This knowledge will be valuable for its own sake. By
showing us the impact of logging and clearing, it will also help us decide
how to manage our secondary forests. It will help answer questions
like: How often should we log our forests? How big an area
should we log at once? Should we clear cut or log selectively? How
much should we leave untouched?
|3. Inspiration: Old-growth forests can take your breath away.
Sometimes, old trees are big and tall like the pine that is over 150 feet
tall in the town of Florida, Massachusetts. Sometimes they are withered
and gnarled like the weather-beaten oaks of Mount Wachusett. In both
cases, the feeling of being with another living thing that is hundreds
of years old is humbling and inspiring. Here is a big pine at an
old growth site in Northwestern Massachusetts.
Picture: F. SaintOurs
Some people get so excited about big trees that they search them out, protect and propagate them. To find out about the Champion Tree project, visit this site.
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