Stand density index

The stand density index (SDI) is a measure of the degree of concentration in the forestry , which was developed by Reineke in 1933 in the US. He had observed that uncultivated and fully stocked forests of a certain tree species, regardless of age and yield class, achieve the same number of trees per unit area if they have the same mean diameter. Reineke used a 10 inch diameter as a reference  .

Daniel and Sterba translated the SDI into metric and used a mean diameter of 25 cm as a reference scale. The formula is:

${\displaystyle SDI=N\cdot \left({\frac {dg}{25}}\right)^{1,605}=N\cdot \left({\frac {25}{dg}}\right)^{-1,605}}$

in which

• N = stem number / ha
• dg = circular area center stem cm

Web links

• Information Switzerland. Forest inventory
• Shaw, JD 2006. Reineke's Stand Density Index: Where are we and where do we go from here? (PDF; 491 kB)