Several days ago there was a storm at the farm that my brother and I share, a large decaying white oak tree came down during the high winds, about half the tree was in the soybean field so we decided today was the day to cut it up. started with a small limbing saw to cut up smaller limbs. After cutting up the decayed limbs, started on the seasoned but not rotten limbs. Wow, this stuff was hard. Chain didnt last long on this. Then picked up an 026 Stihl with 18" bar and cut all limbs down to the logs. By this time this chain was shot too. Next saw was an Stihl 362 with 20" bar. while cutting up logs in lengths I could handle the logs were smoking from the sparks coming off the chain. We had to pour water on the log cuts to stop the smoldering . My brother tried to cut out the smoldering wood with a razor sharp hatchet and it just bounced off. Verified this was due to sparks coming from chain as i saw them visually during cut. Chain super sharp when started . Been around chainsaws for probably 50-55 years and never have I encountered wood so hard it would try to start burning just from a chainsaw making a cut. Any of you guys ever encountered this before?