I have several large pig nut trees (like Hickory nut's). After the squirrel's are done they leave a mess. What would work for raking up the nut hull's. I considered a landscape rake but I don't think it would work. I'm open for suggestions.
If the ground under the trees is pretty flat, a boxblade should work well, especially if it has some short grass - the grass will help keep the boxblade from gouging the ground. Obviously you'll need to get the level right on your blades - I have a hydraulic toplink that makes that quick & easy. Your 3pt will let the boxblade float over small humps etc. and in the low spots it will leave some debris but overall it will gather up alot of it.
If you have a FEL, I would recommend tilting the bucket so the bottom edge is at about a 30 degree angle to the ground , pointing forward, floating the bucket, and back dragging.
I would try a pull-behind sweeper. I have an "Agrifab" bought at Lowe's. Sears sells a Craftsman that's similar. Think mine is 42" wide, and it does a pretty good job on such trash.