This time of the year we cook on the fire pit most evenings. I'm assuming you're talkin' 'bout open grilling, which should be approached differently than "smoking". When "smoking" food, the choice of wood species can be very important.
I don't have all the different species that's been mentioned in this thread available, but I've never found any wood that will produce a bed of coals to be actually "bad" for grilling over. Some would think elm should leave a bad taste... but it is my "go to" when I need a long, hot burning coal bed for things like chicken. Something that cooks relatively quick, such as beef steak, can be cooked over near any short-lived coal bed... but because it is a "sliced" meat it will pick up more flavor. "Sliced" meats are best over hard maples and oaks IMHO... but I've done them over most anything 'round here except Box Elder, and I don't remember any of them being "bad".
The trick is to build the right type of fire for cooking (grilling), and one the will heat long enough for what it is you're cooking. If the coal bed cools before you're done cooking it's near impossible to add more "fuel" to the fire without creating flame and excessive smoke... flame that will burn and scorch food, and excessive smoke that will soot-blacken it (not to mention it gets in your eyes). Some woods coal-up better than others, some coal-up faster, some create "hotter" coals, some create longer burning coals, etc. I like to use split firewood, small splits (like 2-3 inches), because they burn and coal-up fast and evenly... learning how many to use is a trial 'n' error thing depending on the type of wood and what you're cooking.
I can tell you that...
I don't have all the different species that's been mentioned in this thread available, but I've never found any wood that will produce a bed of coals to be actually "bad" for grilling over. Some would think elm should leave a bad taste... but it is my "go to" when I need a long, hot burning coal bed for things like chicken. Something that cooks relatively quick, such as beef steak, can be cooked over near any short-lived coal bed... but because it is a "sliced" meat it will pick up more flavor. "Sliced" meats are best over hard maples and oaks IMHO... but I've done them over most anything 'round here except Box Elder, and I don't remember any of them being "bad".
The trick is to build the right type of fire for cooking (grilling), and one the will heat long enough for what it is you're cooking. If the coal bed cools before you're done cooking it's near impossible to add more "fuel" to the fire without creating flame and excessive smoke... flame that will burn and scorch food, and excessive smoke that will soot-blacken it (not to mention it gets in your eyes). Some woods coal-up better than others, some coal-up faster, some create "hotter" coals, some create longer burning coals, etc. I like to use split firewood, small splits (like 2-3 inches), because they burn and coal-up fast and evenly... learning how many to use is a trial 'n' error thing depending on the type of wood and what you're cooking.
I can tell you that...
- Ash doesn't coal-up worth cold owl squat, and what coals you do get burn cool and fast... I won't use it for cooking.
- Walnut coals-up OK, but tends to ash-over rapidly causing a cool burning coal bed, stirring them to get the heat back sends piles of ash floating up into the food... it's hot-dog cooking fuel.
- Most pines and firs will make a bed of coals real fast (handy if you're in a hurry), I would rate both the heat and available cooking time as moderate... great hamburger cooking, fine for most vegetables and "sliced" meats, but there are better choices if time ain't a factor.
- Oaks and hard maples make wonderful coal beds with plenty of heat and time for most cooking... you can cook your potatoes and whatnot, and still have plenty of heat left for your "sliced" meats.
- I ain't found any wood that will produce a bed of coals that burns longer and hotter than elm, perfect for chicken (whole or cut), whole ham, whole turkey breasts, and the like... plus, there's still enough heat after the meal so kids can roast marshmallows and such.
- Cherry ain't the best "grilling" wood, but if you "knock-down" the fire just before it turns to coals you can get a pretty good "smoke" going that will add some unique flavor to sliced meats... I often use cherry for grilling pork chops, sliced ham, ribs that have been pre-baked, and the like.
- Soft maples and such are fine for burgers, hot-dogs, bratwurst, cheaper cuts of beef such as round steak, cheaper cuts of pork such as those "steak" things... for the most part I use soft maples for late evening "sit-around-the-fire" fuel.
- Willow, Basswood, and the like just refuse to make a usable coal bed... trying to cook over a flaming and/or excessively smoking fire sucks sour owl crap.