We have submitted our reply for the Forestry Department's query on deforestation and we got a positive reply (partially reproduced below).
The following conditions must be included literally in the permit conditions of the environmental permit:
The license is granted on the basis of Article 90bis, §5, third paragraph, of the Forest Decree and under the conditions as included in the attached compensation form with reference: XXXX.
The area to be wooded is XXX m². This area no longer falls under the scope of application of the Forest Decree.
The remaining forest area of XXX m² must be preserved AS FOREST. Additional logging in this zone can only be carried out if authorized by the Agency for Nature and Forest. It is also not permitted to erect structures in this zone or to make radical changes to the soil, the litter, herb or tree layer.
Deforestation can only be carried out in accordance with the plan added as an appendix, on which the areas to be preserved as forests are also indicated.
The forest conservation contribution of € XXXX must be paid within 4 months from the date on which this permit may be used. The transfer form for settling the forest conservation contribution will be sent directly by our Agency to the applicant as soon as the permit comes into effect
So, weeeeee! We can cut trees and build the house on the designated plot.
... Aaand we need to pay a lot of money for the environment to do that :( Frankly, I would have preferred to plant trees, but that's not so straight forward.
Oh, well :)