With trees that are closely-spaced then perhaps the original mapper should have used natural=wood for the area but didn’t know of that tag. If there are large gaps between tress (so you can easily make out individual trees in aerial imagery) then individual trees is a better representation of what is there.
Did the original mapper specify the height of at least some of the trees? In which case they may have deliberately been mapped that way in order to allow pilots to figure out in advance what areas were safe and what were risky. Yes, you should be lined up with the runway to land (with allowances for cross-winds) but if you have to pull up and go around it may be that your only option is (for example) to turn left because ahead and to the right are very tall trees. Depending on where the trees are in relation to the runway, knowing the heights of at least some of them could be vital.
As n76 pointed out:
I would add that n76’s advice is especially true if you don’t need to add anything in the area that has the trees, because if you’re not doing anything in between the trees the clutter isn’t affecting anything (except your sense of propriety). but it’s also true even if you do have to add things (say picnic tables or benches). Unless it’s an actual wood with closely-spaced trees and you’re sure that none of them have been given heights for the benefit of pilots then leave well alone. Even if they haven’t been given heights it’s possible that there are clear gaps between them that might be useful in the event of an aborted landing and that those paths would not be visible if they were replaced by natural=wood.
Even if you think there is good reason to change it, it’s probably a good idea to try to contact the original mapper first.