Station 14: Tree Growth

Red pine grows rapidly but requires lots of sunlight to survive, while the Norway spruce, although severely suppressed, was able to survive and grow slowly in the shade. Shade tolerance is an important factor separating early-successional, or pioneer, species such as aspen, paper birch and red pine from late-successional species such as beech, sugar maple, hemlock, and spruce.

The two disks above were cut from two of the former plantation trees in 1990. The large one is a red pine; the smaller one a Norway spruce. They were both 64 years old when they were cut. Each concentric ring in the stem represents one year of growth. Notice how small the rings are in the spruce and how much the growth varies from year to year on both disks.

Events that affected Growth:

Many things affect growth rates including natural events and human activity. The color -coded pins identify the years of some events that influenced the growth of these trees. For example, the white (inner most) pin denoted the 1938 hurricane in both disks.

Click on the pins below (or color) and see what happened that year

• White
• Green
• Yellow
• Purple
• Blue

The split in the red pine has formed as the disk has dried out and the outer rings have shrunk more than the center ones.