Tree density gives foresters an idea of how closely trees are growing in a given area. This value is always expressed as trees per hectare. The tree density is not an exact number of all of the trees in the region, but it serves as an estimate. This calculation method is called point-quarter and it divides the area into quadrants for taking a sampling of trees.

Stretch out a string along the length of the area you are measuring. Use the measuring tape to determine the length.

Mark five points along the line.

Lay another string at a perpendicular angle to the main string at each point to make four quarters at each point.

Stand at the point and look to the quarter in front and to the left of you. Find the tree closest to the point measuring 4 inches across at four feet from the ground. Use the calipers to determine the width of the tree. Measure the distance in meters from the starting point to this tree and write it down. Repeat this method with three other trees in the other quarters for that one point. Repeat the same procedure for the other points you created along the main line.

Add together the distances from the four trees to the point and divide the distances by four to find the average distance of the trees from the point. Repeat this for the remaining points. Add these average distances for all five points and divide by five to find the overall distance of the trees in meters.

Multiply the average distance in meters by itself to find the average area each tree takes.

Divide 10,000 meters squared by the average tree area to determine the tree density per hectare.