Fig. 3

Illustration of translating the top height h_top(i) of a species in a stand at age i to the corresponding height h_top(100) at the reference age of 100 years, i.e., the SI; green points mark heights and ages of NFI spruce plots; the solid black curves show the fit of the Chapman-Richards function to the 5 and 95% quantiles; the black dot marks an example stand at age 60 with a top height of 28 m. The black cross marks its translation to h_top at age 100, resulting in a SI of about 32 m