hi i have recently brought a farm in Costa Rica on it are a lot of orange trees, all these have crowded branches shooting straight up. they no longer produce very many fruit as they are old and unlooked after. every where i look it says grafting is done with old scions to new root stock, as these are old trees and well established could i take old scions from the top of these trees and graft on to the trunks farther down , then cut out all the over crowding. all is it better to take out all trees and start again. these trees only produce a little but it is very sweet and tasty.

please help as im new to citrus farming and normally only deal with livestock.

thankyou mark.