Canopy Cover

A Habitat Suitability Indicator

Scientists have found that forest carnivores need quality old-growth habitat to survive. The tool at right measures forest canopy cover. A researcher is counting squares on the mirror. How many quarter-squares do you see visible on the mirror's face? After they count, scientists apply a formula to estimate percent canopy cover and record their findings onto a data sheet. From your view, what percent canopy cover do you see? Here is the formula they use: a) count the number of quarter squares which are mostly sky (there are 24 squares and 96 quarter-squares), b) multiply by 1.04, and c) subtract your answer from 100 (%). What is your estimation?

Researchers have demonstrated that a dense forest canopy is an important characteristic of good fisher habitat.

Below are a couple of questions that relate to this chart:

 
What percent canopy closure best suits fishers?

0 to 50
75 to 100

Diameter breast height (DBH) is the width of a tree at about four and 1/2 feet above the forest floor. Would fishers likely be found in habitats with trees averaging less than 13 inches DBH?

Yes
No

Chart Comments:

• Mean Overstory (DBH) is the average diameter of the trees that reach into the upper levels of the forest canopy.
• Percent Tree Canopy Closure is the amount of canopy cover overhead.

Back to Forest Carnivores

Habitat Suitability Chart (modified from Allen, A. W. 1983. Habitat suitability index models: Fisher. U.S. Fish and Wildlife Service, FWS/OBS-82/10.45.)