1. photograph the event if possible;
2. Write a brief statement about the event and describe as precisely as possible how to arrive to the location (if there is a correct address, some visible object, distinctive sign and the like.).

Whom to contact:
If it is potentially illegal to cut trees on a public green area in the issue at hand, forward the statement along with photos to the municipal police in your city/town and/or the Green Phone service for your County (072 123 456)

NOTE: You can always call the service 112, especially if it is a matter of great urgency, and during the weekends, holidays or at night