Division II.7 Treatment before analysis

The determination of the mass of 100 leaves or 1 000 needles, as well as the shoot mass, shall be used for the intensive and continuous surveillance on the permanent observation plots and the current year shoot.

It is not necessary to cut the petioles of the leaves but in case of compound leaves it may be advisable to detach the small leaves from the axis if this has not been done in the forest. To avoid contamination, no powdered plastic gloves shall be used.

It is not necessary to systematically wash the samples, but it may be advisable in regions with a high level of air pollution or near the sea. The samples shall be washed with water without any additions.

Oven drying shall be done at no more than 80 °C for at least 24 hours. The needles shall be removed from the twigs with the same precautions as for detaching the small leaves from their axis.