The European Union aims to be carbon-neutral by 2050 as part of the comprehensive Green Deal that was agreed upon four years ago. However, an analysis of the policy documents outlining the practical measures of the Green Deal shows that it will decrease carbon emissions in Europe, but also increase carbon emissions outside the EU.
3billion trees sounds like a lot, but the area it takes to plant those trees is less the 1/1000 of the area of the EU. I highly doubt, that this would lead to a measurable decline in EU farm land and especially high quality farm land.