Division IV.2 Criteria for the selection of sample trees

Criteria for selecting trees are:

Trees should be selected from those on which crown condition assessments are carried out. Preference should be given to trees that are clearly visible when standing outside the plot, because the high frequency of the observation may affect the condition of the ground vegetation on the plot.

If there is an insufficient number of crown condition trees visible, it will be necessary to select additional trees from the plot or from the buffer zone. In this case:

• trees should be dominant or co-dominant,

• trees on which periodical measurement of DBH and height is (planned to be) made should be preferred,

• trees selected for leaf/needle sampling and analysis are not to be included.

Between 10 and 20 trees per species on a plot are selected for the sampling. All trees should be numbered. If they already have numbers (e.g. for crown condition or increment assessment) these numbers shall be kept and used.

If a selected tree dies or is removed it can be replaced. The newly selected tree should be given a new number and it shall be registered and reported to the Commission.