There are still some very mature trees on this lot so I've decided to use them as Surrogates for new trees being added so I let the Surrogate decide when it is time to add a new tree too its care. As the larger limbs fall they are collected and used to build a makeshift frame/nest along the drip line. The smaller limbs are collected from same and broken/cut into 2"-4" lengths and dropped into a kitchen trashcan until it is full. When the nest/frame is complete and the can is full of limb cuttings a new tree is planted within the frame. I dig a hole which leaves about 1/4 of the potted tree above ground, fill the hole with lake water, plant the tree and then fill the frame in with the whole can of clippings. Flowers and a nitrogen builder (beans, clovers, etc) are added within the frame to complete the family.