Mike,
I've seen lots of building materials that are banded into bundles just dumped. I cringe. But it doesn't hurt them (much), and doesn't matter for rough framing. I personally wouldn't want all that expensive (and soft) redwood hitting the ground that hard, especially since the kids are going to be in direct contact with the playset.
One unloading trick that my Dad used to use because it was fast and relatively safe was old tires. The tires were usually handier to get than a big machine. Put the tires (no rims!) on the ground to cushion the impact. Make sure you take into account how far the load will slide before it tips. Keep everyone away.
I like tow straps (larger the better) over chains any day. The straps are very strong and absorb shock well. I avoid chains whenever possible. Properly sized and used chains are ok, but if you have ever been in the vicinity of a chain that broke under pressure you will know how scary it can be.
Anytime I pull (chain, strap, cable, etc.) I prefer something solid between my body and the chain and/or a short enough lenth that if broken it cannot physically reach me. I pretend that the chain is a huge rubber band. If I am looking down the length of it, or anywhere close, I stop and re-rig.
Hope this helps,
Patrick in Ohio
