Please add to this as you cook with new woods so maybe we can come up with a good list of opinions to help all of us get a handle on it.
I apologize for some of my terminology but I grew up with them and this aint an exact science...
General Observations:
Don't waste your money on lumber i.e. oak boards from an old household project - it's been kiln-dried and will usually only yield heat - almost no flavor compared to the tree before the saw mill. You can get heat from charcoal for a lot less money.
Bark should be limited to the natural level.
i.e.: just the outside surface of a 3 inch round - don't haul home a bunch of the "bark cuts" from the local saw mill cause you'll end up with over 50% bark - not good flavor. and assort as you throw in your wood throughout the cook
Only fruit-bearing trees should be used - never burn pine or fir, etc. you'll ruin the meat and possibly the cake in the smoker - have to strip it and start over.
To my knowledge, Hickory is the only wood you can cut in the morning and cook on it that night. Everything else should be blocked, split, ricked and let dry/season for at least 6 weeks if not 4 to 6 months. After about 2 years, most woods will get "doty" and won't yield much heat and start to smell "dusty" so I never hold mine longer than a year so I can burn it before it reaches that age.
For blending purposes I group woods in three categories: Strong, Fruit and Mild.
Strong: Hickory, Mesquite, Ash
Fruit: Apple, pear, peach, plum, grapevine, pecan, cherry, etc. (ornamental varieties not included - example: Bradford pear)
Mild: oak, alder, mulberry
My favorite technique (partly because I live in Nebraska where we don't have much for fruit woods) is to blend Hickory (my favorite) with one of the fruits. Maybe 1 part Hickory to 2 or 3 parts apple. Just throwing in 1 split of Hickory with 2-3 splits of apple is close enough. If you're using a pellet drive then just count paint cans of each into a big trash bag - you get the idea. Same with making chips with a sawzall so you can burn them over charcoal. OH! and keep and bag and label your sawdust - great for cold smoking - for that cold smoker you're going to build someday.
A couple observations:
Not sure about Walnut but I've heard bad things so I've never tried it.
I've heard pecan shells are great to cook on. You can buy pecan shells perty reasonable (50 cents/pound) from places that sell the pecans. Or you could use them like wood chips on a charcoal fire...
Mulberry doesn't seem to put out the heat like the others so you may have to help it out...
Hope this helps.
