I sawmilled for a customer yesterday that owns/operates a tree removal service. There are times when he has to remove trees from homes, etc. where the tree needs to be absolutely controlled to prevent damage or further damage. He designed, built, and has a patent on an attachment that will allow the grapple on a skidsteer, etc. to swivel to various positions including upright.
This attachment has it's own quick connect/disconnect and simply sandwiches between the skidsteer and the grapple. He has hydraulic extension hoses to allow for the extra length needed when the unit is swiveled to 90°