An EIA is required for some planting schemes in the UK. The intention is to ensure there are not negative impacts from the planting of trees, such as loss of rare species, major landscape impact or damage to archaeological feature. These are mainly a requirement for larger scale forestry planting but are often required for farm woodland and agroforestry schemes too. Small proposals (under 0.5 ha) and projects on less sensitive land are presumed not need one, though this is not guaranteed. It is advisable to seek professional help if you are unsure.
More on the legislation on Agroforestry in Belgium, you can find here.
The owner's authorisation is required for an agroforestry project, especially if it is aimed at producing timber.
In all cases, it is essential to ensure that there are no underground services within the plot (fibre optics, pipeline, gas pipeline, drinking water pipe ....). If necessary, a tree-free buffer zone should be established, which may be 20 to 50 m wide depending on the type of network.
For more information on Agroforestry in the Netherlands, please visit the website of Agroforestry Netherlands (Dutch).