How Old Is Our Forest?
forest of Maine has gone through many life cycles since becoming
established around 6,000 years ago. It still changes constantly. Trees
die and new ones sprout up all the time.
Natural disturbances such as wind, insects, or disease kill some trees. When natural disturbances happen on a small scale, fallen trees create a gap in the forest, allowing sun to reach the forest floor. Young trees sprout up in the sun. The result is a forest of many ages, or an uneven-aged forest.
Large-scale natural disturbances create a different picture. Wind, insects, disease and fire can affect vast areas, resulting in the death of many trees. The result looks messy; some say it looks devastated, but the forest itself does not die. While there are exceptions, typically populations of young trees sprout up in the wake of most large-scale disturbances. The result is a “Baby Boom”, or even-aged, forest composed of trees of the same age.
Natural disturbances and human intervention shaped the forest of today. Both will shape the forest of tomorrow.
White pine is the most common conifer, or cone-bearing tree, in the southern part of the state and grows abundantly in even-aged stands on old farmland.
Between 1890 and 1920, Maine’s conifer forests were heavily cut to supply a national building boom. At the same time, a spruce budworm outbreak, beginning in 1912 and lasting until 1920, created a
natural disturbance that reshaped the forest in northern and eastern
Maine. These natural and human events combined to set in motion the
cycle of natural regeneration, or sprouting up, of a young spruce
and fir forest.
This even-aged spruce and fir forest reached maturity in the 1970’s, making it susceptible to spruce budworm once again since this pest favors mature trees. Industry stepped in and harvested large tracts of budworm damaged trees during the 1980’s in a move that triggered a contentious debate about clearcutting that continues today.
Nature also shaped the forest with large-scale weather events, including the 1938 hurricane, the 1947 forest fires and the 1998 ice storms.
Settlement to the Present
After the Civil War, eastern
farmers migrated west looking for better farmland and for employment in
the city. Young trees sprouted up in abandoned farm fields, creating
even-aged forests. In fact, most of the forests we see today in southern
Maine were once fields.
Forest Today and Tomorrow
Maine is once again almost 90% forested, but it is a different forest than the one prior to European settlement. Today’s forest is mostly made up of trees less than 100 years old.
Older trees do exist. In Maine, there are 93 old growth stands. Of these, 11 sites are larger than 50 acres and 37 sites are smaller than 10 acres.
For the most part, old growth forests remain because the sites are too inaccessible to log. Some have never been cut. But trees die
over time even if
they are not cut down, so old growth forests are composed of young,
middle-aged, and old trees. Still, old growth stands have many trees 150
to over 200 years in age.
The forest continues to change. Large areas of spruce and fir clearcut in the 1980’s now support a young even-aged forest – thus potentially laying the groundwork for another budworm epidemic when the spruce and fir mature. And, as population growth in southern Maine fuels development, it is clear that some change is permanent.
SUCCESSION OF A FOREST
#40: Then and Now
#80: Nothing Succeeds Like Succession