0.005454 DBH2, where DBH is located at 4.5 feet above the ground surface calculated in inches and is the diameter of the tree. When you are calculating the basal area you may need to have more calculations for stands that are larger whereas if you have a stand that is smaller it will require fewer basal area measurements to be taken. The base number for the number of measurements that should be taken in a stand is 20 – 25 and this should give you a good estimate for most stands. When calculating basal area foresters use a special prism or gauge that can help get precise estimates. Not every stand is a uniform stand and so numerous measurements will need to be taken at the same spot so that you can have precise measurements in the stand. Trees per acre When looking at stocking it is also important to account for the trees per acre in your stand. This follows the same principle of basal area. When looking at the trees per acre make several estimates in the stand and take the average so that you have the most reliable source of information. See also Stand level modelling References Stocking