pixie...they are loaded with what we call "old mans beard".it's almost like in the swamps where you see the moss hanging off the trees.it burns hot and fast.the trees themselves have almost half dead limbs on them.if you have ever seen a pic of a christmas tree that has dried out that catches fire,these are the same way.then you pack all those trees together and it is a fast-running,hot fire.there are homes within 1/4 mile,and the military has their ammo storage within a mile on the other side.the state of alaska learned the hard way about these trees in 04 when a small fire that started by a lightning strike on blm land(which they don't fight)(and they are in control of ALL the parks)anyways...that small 60 acre blaze grew to 7 million acres before the state of alaska got it put out.we leave as many pockets of birch and aspen as possible as they will seed a very large area.the black spruce just chokes out any other trees.the div of forestry has determined it is much easier to control the direction and fightability of a fire before it even starts.besides,it creates a very nice moose habitat,they don't eat black spruce,but love the grasses and small birch saplings that will appear.we had moose every morning in the new field eating the tops off the small birch that actually did get cleared.we couldn't save them all.i hope this anwered your question and enlightened you as to why we must do this.add in the fact that we have a massive amount of beetle killed spruce,which is throughout alaska,and we can't log it......and it is a potential disaster waiting to happen....bill w