Measuring tree volume

How much wood is in that tree?How much is that tree worth?

Tools Needed

• Clinometer – used to measure the height of the tree

• Tape measure – used to measure the diameter and distance from the tree

• Calculator – used to calculate the board footage in a tree

• Log Sheet – used to log in all the measurments we take in the field

Using the Clinometer

• A Clinometer is a tool used to measure angle and will be used to figure out the height of the tree. It has degrees to measure the angle

Tape Measure

• When measuring the diameter, measure in total inches and then divide by 12 to give your dimension in feet.

37 inches in diameter will be = 3.08 ft 37/12 or 3.08 ft

Calculator

• A simple calculator will work fine for this exercise. We will be using a table of information for you to make simple calculations.

Log Sheet

• The only way to keep track of the trees we measure is to log all the information.

• Board Footage Data Sheet • Tree # _____

Tree species: ___________________ • Height _____ feet • Diameter _____ inches • Diameter in feet / 2 = ________ radius in inches / 12 = _____ feet • Area of tree cross-section = above number squared x 3.14 =______ sq.ft. • Volume of tree in cubic feet = above number x tree height / 4 = ______ • Volume of tree in board feet = above number x 12 = _________• What the tree is worth in material= above number x BF cost ____________

Measuring the Height of the TreeBy using the formula ab x Tangent A = X, we can determine the height of the tree, where:

ab = the distance from the treeA = the angle of elevationX = the height of the tree

Tangents are determined by using tangent charts (See the chart )

Tree height samples• Example 1:• if A = 35 feet, and B = 34°, then the tangent of B = 0.6745• 35 x 0.6745 = X• 23.61 = X (the height is approximately 24 feet, or 7.3 m)

Tree height samples• Example 2:• if a = 35 feet and b = 60°, then the tangent of A = 1.7321• 35 x 1.7321 = X• 60.6235 = X (the height is approximately 61 feet, or 18.6 m)

Measuring the tree

• To measure volume of the tree, 5’ above the ground measure the diameter of tree.

• To get the volume– Diameter is equal to Circumference / 3.14Example : Circumference = 28”

that is 28/12 = 2.33 feet2.33’/3.14 = .75’

Getting the volume

• After we get the diameter we need to find the area of the tree

• Diameter/2 to get your radius• Area = 3.14 x r2

• Our area in the previous example was .75• .75/2 = .375• .3752 x 3.14 = .44

Almost there!!Cubic Area of the tree

• Cubic Feet = Area (ft) X Height (ft) / 4

• We found the area in the previous example= .44Now we multiply .44 x 61’ and divide by 4

WHY divide by 4? It accounts for the taper of the tree

Our total cubic feet in our tree is 6.71

Final total

• 1 cubic foot has 12 board feet of material in it.

• That makes our tree have 6.71 x 12 =

•81 board feet of material in it•It is an oak $3.25 per BF•Our tree is worth •3.25 x 81 = $263.25