Platform users must acknowledge the ‘Principle of Additionality’,  as such only trees explicitly planted for the purpose of sequestering CO2 will qualify for Carbon Credits.  Consequently, you could not register a tree that has already been planted or plant trees intended to be used as a source of Biomass energy.  However, it would be acceptable to plant new saplings and delay registration for up to 2 years to ensure they are established before registering them on the platform.