Restoring the golf course to its original design is the execution of a Dept of the Interior project designed by landscape historians from University of Pennsylvania during the Obama administration, but lacking funding until now.
t.co/CPtQFZ0j2v
The study includes a detailed history of land management on the island over time. (I read it.) This includes documented design intentions by the original course designer, Walter Travis. Among those were creating vistas from the course that provide views of specific DC buildings and monuments.
Since that time, trees have grown taller and later plantings interfered with those views and the original vegetation layouts. The trees being removed have been identified by arborists and park personnel - not Trump, LOL! - because of a combination of their poor health, the presence of invasive species, and their location vs the historic plan restoration.
There are 3800 trees in the island area in and around the golf course. Removing these ~500 trees did not denude the area. I'm not a lawyer, so have no opinion on the legal aspects of the discussion.