These include quadratic mean diameter QMD mean tree height basal area BA etc. Used in forestry is not the arithmetic mean of diameters but the quadratic mean quadratic mean diameter E d. The application of 8080 kg P and K per hectare significantly increased the quadratic mean diameter at breast height DBH from 200 to 230 cm.
When the quadratic mean diameter equals 10 inches 250 mm the log of N equals the log of the stand density index.
Quadratic equations are equations whose highest power in the variables is 2. The mean circumference MC is also the cutting length. BUT we want D q in inches therefore we need to include a conversion from feet for BA to inches for D q. The historical and practical reasons for this convention are.