Another newbie

[Boating Bill]

Hi, I'm Bill, a maker of sorts, always interested in building new tools for use around my home and out at the ranch. I'm a whitewater boater by heart and I'm thinking about modifying a small cargo trailer with rollers and a simple winch so I can load my 14' inflatable raft already rigged with frame, dry box, and cooler. Broke my back a couple years ago so I'm not supposed to lift much heavy stuff anymore.
I also have a Cat D3 that I use for logging on a steep 5-acre parcel I own. The drought here in CA and beetle infestation have killed about 200 large Ponderosa, sugar pine, and white fir so I'm looking for ideas of how to make a tree spike to fit on the ROPS to either push them over or push them in the direction I want them to fall when cut. Many will be difficult to access, even with a small Cat so I will need to figure out a snach block/winch system to pull them where I want them to fall.
Then what do I do with all that lumber? Build a mill?