In a natural state growing closed forest the amount of timber grows yearly. However, in the same time the timber volume also decreases when part of the trees die in the competition for light and other growth factors.
There are many interactive functions and characteristic that influence the growth and drain in a stand. These can be illustrated as mathematical models. The article discusses a set of models.
The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.