For the inventory, we record all trees with a diameter of at least 12 cm at breast height (1.3 m above ground). Every 5 years, we document the stand structure, the stock (standing volume) as well as the wood increment (volume change) at all LWF sites. All trees are numbered and marked at 1.3 m.
We record the following main parameters:
- tree species
- diameter at breast height (DBH, derived from the stem circumference at 1.3 m height) with girth bands at the mark
- tree height, crown base height and maximum crown width with an ultrasonic instrument for measuring distance and angle (see Fig. 2)
- further parameters include: live/dead/decaying degree, tree damage, crown competition, forest type, etc.
In order to determine wood supply, we estimate the wood volume of each individual tree from its diameter at breast height and total height. We use specific empirical equations from the National Forest Inventory (NFI) for each tree species and region.