Forest Gaps

Trees compete for light. Some species are better at this than others. For example American beech and sugar maple can survive with very little light. They are said to be shade-tolerant. They can even reproduce under the shade of mature trees of their own species. However, shade-intolerant trees like walnut, butternut, and persimmon cannot grow under shade of other trees. In fact these trees need gaps in the forest to be able to get a foot hold. When wind or soils saturated with water cause a large tree to fall, this provides opportunity for species that need a lot of light. Without such disturbances, forests might march toward having mostly shade-tolerant trees. If a tornado flattened the forest, it would take a long time for it to recover. But an icestorm that topples many trees may be good for the forest. Intermediate disturbances, such as this, promote diversity in the forest by slowing ecological succession. Logging can either be an intermediate disturbance or a severe disturbance. Clearcutting is a severe disturbance that takes years to recover from. But selective cutting can often increase diversity. We used horse loggers because horses are limited to pulling shorter logs. Mechanized skidders pull out whole trees and do a great deal of damage to nearby sapling and seedling trees.                

  Published 30 May 2014 ;  last modified 27 March 2018          © Clay Hill Memorial Forest 2014