I've never used alder, period. It's not available here in Arkansas to the best of my knowledge. I did a Google search and found many references to white alder and smoking meat. Here's both a link and a quote:
http://www.ideadobe.tehama.k12.ca.us/page24.html "The flavor of the finished products depends on the ingredients added to the brine and the type of wood used. Our brine is a combination of salt, brown sugar and water. We use white alder for the smoke due to its distinctive flavor. The recipe for our jerky and other foods prepared during our programs is available in the book..."
Here's the link to my Google search:
http://www.google.com/search?hl=en&lr=&q=smoking+%22white+alder%22 Hope this helps!