How to Calculate Shade Factor of Trees


Trees of any variety are ideal additions to any landscape, providing natural beauty and oxygen, shade for energy efficiency and UV protection, tree houses, fruit, nuts and flowers. A tree's shade factor is a technical term that refers to the overall amount of sunlight blocked by the tree---and knowing this information can help you understand how much shade your tree will provide, and also help with measurements for tree spacing and planting. Keep in mind, though, key factors when calculating the shade factor of trees for your landscape.

Step 1

Figure out the crown spread of your tree, which refers to the tree branches' average area. Use the measuring tape to measure the most narrow and widest points of the spread, then average them out to get the tree's crown spread.

Step 2

Figure out the height of your tree, as accurately as possible with a clinometer, a tool used in forestry (available at your local hardware or gardening store, such as Lowe's or Home Depot). This device calculates distances and angles to estimate an item's height (in this case, the tree). Depending on the type of clinometer you choose, follow the directions exactly.

Step 3

Include variables such as tree health, leaf type and variety, seasons and region. For example, trees in the northern United States will always cast longer shadows then places that are far south, because of the sun's angle.

Step 4

Combine the estimated shade length of the tree with the crown spread to calculate the tree's overall shade factor.

Things You'll Need

  • Long measuring tape
  • Clinometer


  • American Forrests: Measuring Tree Shade Factor
  • California Tree Registry
Keywords: tree shade factor, about trees and shade, calculating tree shade

About this Author

Lauren Wise is a journalism major from Arizona State University with over forty published magazine and media articles and over 400 Web site articles. Wise owns Midnight Publishing with over eight years experience as a writer, editor, copywriter and columnist. She specializes in food and wine, music and pop culture. Her writing has appeared in magazines including Runway, A2Z, Scottsdale Luxury Living and True West.