I've been thinking on this quite a bit this week. There's been quite a bit of supposition and assumptions thrown out about ERC and no one has done more of it than myself. I have had no luck with trunkwood and yet many others have made fine bows from it. Heartwood showing on the back as always spelled disaster for a selfbow in my experience. However, someone mentions that another made selfbows using only heartwood. There are many, many contradictory reports of what works and what doesn't. I've decided to setup a little more controlled experimentation. I intend to cut samples of limbs and trunks from in the open Sun light, shelter belts and from under canopy. Cut 30 samples each and keep accurate records of growing condition, RPI and any other pertinent information. The plan is divide each sample group into thirds. One third will be untouched sapwood back, one third decrowned back, and the last bit heartwood backed. I'll cut them all the same day and store them the same way to season. When seasoned I'll start the testing procedures(sort of like the slat bending test) and record my findings. I've built quite a few ERC selfbows and blew up a lot of attempts, but it occurs to me that even at that, it's not enough experience to be telling others how to go about it. When I learn more I will share my findings. I apologize if I've led anyone a stray. Josh