We have been clearing some old growth pine that has grown slowly on bedrock around our cabin/cottage. It is on top of a bedrock ridge with no nutrients other than it's own needles and the water it can get when it rains. The technic we use was to winch the whole tree over to expose the clean rock. The near root system is cut out of the extended root system. Which leaves you with a tree together with the near root system to remove. It is hard work but the result is granite bedrock to walk on...
- Use a decent high pressure hose with at "turbo-nozzle" to cut thru the root mat and/or clean the wood before using your saw. We would cut wheelbarrow-size chunk off the root system by "cutting" the dirt with the turbo-nozzle, 2-3" lopping shears for the smaller roots, and a chainsaw for the larger roots. I would have loved to have had a small "bobcat" to help, but all around are wild blueberry bushes that need to be undisturbed.
- The roots on these very old, very dense, slow growing trees are extremely tough and sinewy. I tried a sawsall with wood blades, demolition blades, everything without efficient results. The Stihl Duro (carbide) chains are very good, but very brittle. If there is any contact with a stone fragment in the root area, the teeth just chip off the chain (the carbide cutting teeth are welded onto the chain). I now have 2 carbide chains, one with 1/4 of the teeth, and one with 7/8 of the teeth. They work very well while they last, but they are expensive.
- The current solution is an old bar, and 2 old safety chains that get sharpened commercially that I keep just for root-work. To hand-file these chains after use is not worth the time IMO.