The Fire Department can tell you all the local rules (permits, days you can burn, when you can light the fire, any other restrictions). I burn when there is a light rain or we've had a light snow, sometimes have to wait a few months. The wait is OK, too many people try to burn when the pile is green. If you can't wait, don't burn if the relative humidity is under 40%. It will take the area under the pile a few seasons to get back to normal, mixing in some dirt from around the pile area 2 weeks or so later can help. Be sure there is a nice clear area (minimum 10-15 feet) around the pile. Trees should be 30' or more away so that they don't get damaged. This is another good reason to burn in the rain or drizzle and in no to low winds.
For starting, I find an area in the pile where the brush is dense. I pour used hydraulic fluid over the area, usually about half a gallon to a gallon. Watch it carefully to be sure it's not going on the ground too much. I go for about a 3' x 3' area. Most places require you to use a "clean" fuel such a diesel (i.e. used engine oil is not permitted). I like the hydraulic fluid because it soaks into the wood better than diesel. If you don't have hydraulic fluid than use diesel, and the next time you change your fluid your tractor, save two gallons. I do this pour the night before, then cover the area with a tarp. The day of the burn, I pour on another half gallon, put some news paper in there. Remove the tarp and light it. You might have to sling a few more cups in there, but usually if the wood is dry enough it has absorbed enough oil that it will burn just fine. The smaller area you have set on fire will then spread to the rest of the pile.
A leaf blower can help spread the fire in a specific direction. I'd have a few drywall buckets about half full available just in case. If you can get a hose to it, do it. Have a shovel and a rake too. If the pile is loosely packed, have a chain saw ready. The chain you use will become your "dirty" chain because cutting the charred wood is hard on the chain. I've used my loader to push a pile that's on fire together, but my rule is that the front tires never go on ground that has had burning fire on it. Most of the time it is for pushing in those handful of big pieces that were sticking out of the fire.
Be prepared to be there all day, and maybe into the night. If you've got debris around the place you've always wanted to clean up, while you're hanging around go get it and toss it in. Makes the day more productive and less boring. Tell adjacent land owners what you are up to. You'll need to check the area every day for a couple of days. You can probably push the ashes together with your FEL at 24 hours after the burn (and maybee even the next day too) so that any big chunks can burn down. Don't drive into the middle of it, just push the sides in by about 2-3' per day. It will take a week for everything to be truly out, so if weather changes you might put water on the pile and then spread the area out. Just think about the size of the pile, what's in there, the weather conditions, and the like. The more piles you burn the better your "common sense" will be. If you're unsure, start with a small 6' diameter pile.
Burning in the woods over an area you've just cleared is very tricky. If at all possible, burn in an established open area. The goal here is to not set roots on fire that can can cause problems 10 days later.
And do NOT use a tire to start a fire! Just about everywhere it's illegal, every time it's happened here there is a fine and you are labeled an idiot for life.
All the usual disclaimers, follow local laws, and did I mention to talk to your local fire department first :thumbsup:.
Pete