Content Area: Natural Resources
Lesson Heading: Forestry
Activity Description: Wood Scaling
Using trees near the school, students can practice determining height, diameter
and cord wood in trees. After gathering measurements they can calculate board feet per
tree knowing:
- Area of a circle is A=r2 x pi. (Area = radius squared times 3.14). Once you have
determined the area at DBH (diameter at breast height) use it to calculate cubic feet.
- Cubic Feet = Area (ft) X Height (ft) / 4 (note: 4 is used to account for the taper of the
tree)
- There are 12 board feet of lumber for every one cubic foot, so multiply cubic feet by
12. You have calculated how many board feet of lumber your tree has.
Design a worksheet for them to calculate with, such as:
Calculations (show the math used to calculate answers)
Tree # 1
Height:
feet
Diameter:
inches
Radius:
inches / 12 =
feet
Area of tree at DBH:
Volume of tree in cubic feet:
Volume of tree in board feet:
Materials Needed:
Worksheet or piece of paper
Ruler
Biltmore Sticks or Tangent Height Gauges
Clipboards
Activity Length: 40 minutes for 10 trees, 35-45 minutes for calculations; gather
materials
Other Comments/Hints/Suggestions: Get students into groups according to the supplies
they have, have them gather for a variety of sizes of trees to see difference in amount of
board feet per tree depending on size.