I couldn't get the Wood Alpha Pack 1.0.0 to extract on my machine for reasons unbeknownst to me. So here is a pack that I created myself all alphas are 512 x 512 and there is a round and square edge version of each one..
Related Learning Tools
ZBrush Related DVDs
Detailing Characters: ZBrush Alpha Library
ZBrush Related Books
ZBrush Character Creation: Advanced Digital Sculpting