How Site Index facilitates growth-modelling in Iptim

When creating a growth model, Iptim allows stratifying it according to any classifier-type variable. Typical options include especies, altitude range, and terrain. Given that the site index (SI) indicates the growth potential of the stand, it is reasonable to want to stratify according to SI.

However, stratifying growth models according to SI is not necessary because the growth models in Iptim always consider the SI of each stand when generating the growth projections (each stand has a SI value which is calculated from the sample plot data using Iptim's inventory model tool). Therefore, stratifying growth models according to SI does not generate any added value to the projections used with that model.

And there's more...

As other variables are strongly correlated to SI, Iptim's logic already takes care of other types of stratification. Take altitude range as an example. As forests in different altitudes grow differently, at different altitudes the stands have different SI values. Therefore, even if you don't stratify according to altitude range, Iptim's SI consideration when constructing growth models will generate stand level projections which are adjusted to those altitude ranges.