Instead of a chainsaw, if you have a lot of small trees you want to
cut, and especially if they are in inhospitable places for your tractor, get a handheld brush cutter. I have an Echo and, it will
cut down trees 4 to 6 inches in diameter down to the ground. It is a beast. It is the biggest model they make with the bicycle handlebars. (if you get one, contact me on how to best position the handle bars. What you might think is not probably not the best way)
One other thing, I had an adapter made and use circular saw blades. I know they are not rated for the high RPMs of a brushcutter but, before I discovered that, I had already gone through about 10 to 15 blades. (I have done a lot of cleaning up on properties). Since then, I have gone through another 30 or so with no problems. However, I have had problems with pieces flying off of steel blades that are typically supplied with the brushcutters. Again, I have had no problems with circular saw blades but, if you go this route, use at your own risk.
When using a big handheld brushcutter the trick is learning how to position the blade so that you can
cut both sides of the tree from the same spot without kickback. Once you learn how to use this piece of equipment, you will be AMAZED at what you can do with it. As for me, my Echo brushcutter is indispensable for cleaning up a piece of property. Much, much easier, much better and much faster than using a chainsaw to
cut down small trees.
Dave in NC