Hey Mitch:
Just wait until you try sinking a pallet!!! I quit using Christmas trees because they don't hold up very long compared to how much trouble they are (I don't use pallets anymore either).
Keep working at it and you'll come up with materials and a system that works for you. I've been putting cover in our lakes for 20 years and just started using bamboo a little over a year ago (although I have been fishing on bamboo that someone else put in for almost 3-years). I have been so impressed with how easy the bamboo is to work with, how easy it is to fish around, how well it attracts and holds crappie and how long it lasts that I don't think I'll be using much of anything else from now on.
Darryl and I put in a couple cedar trees recently because they were right near the water and needed to be cut down anyway. When we got done with the second one we agreed that for the same amount of time and trouble we could have put in 6 or 8 times as much cover using bamboo. I wish I would have thought about or someone would have told me about using bamboo 20-years ago!
I would think bamboo would be plentiful in your area. If it is folks will likely be more than happy to let you have all you want.