The New Jersey Forest Service Community Forestry Program uses the following formula to determine the potential Big Tree Champions:
Circumference of trunk (in inches)
+ tree height (in feet)
+ 1/4 average crown spread (in feet)
= total points.
How to Measure a Trees Circumference
Measure the circumference of the tree at 4 1/2 feet off the ground in inches, or if the tree sits on a slope, 4 1/2 feet from the uphill side. If the tree has a branch or abnormal swelling at 4 1/2 feet, take the measurement where the trunk returns to normal size. If you measure below 4 1/2 feet, make sure to include the actual height where the measurement was taken.
For example: 182"circumference at 3 feet.
How to Measure a Trees Height
There are many ways to measure the height of a tree. You can purchase a clinometer, which will mechanically do the math for you or you can use the stick method that is described below.
1. Hold the stick or ruler at its base vertically, making certain that the length of the stick above your hand equals the distance from your hand to your eye.
2. Move away from the tree while sighting the trunk base above your hand while staying on ground level (or on the same contour as the base of the tree).
3. Stop when the top of the stick is level with the top of the tree.
4. You should be looking over your hand at the base of the tree and, moving only your eyes, looking over the top of your stick at the top of your tree.
5. Measure how far you are from the tree and that measurement - in feet - is the tree's height.
How to Measure a Trees Average Crown Spread
Measure the crown at its widest and narrowest widths. Find the average crown spread: add the two measurements and divide by two.