Your last point about hewing small diameter white ash is interesting. I have noted in the Bayeux tapestry that small logs were positioned leaning against a forked tree and then hewn downwards with a "T" profiled axe. I have of late been splitting cedar fence post and then flatening these up on one side using a hatchet. Without realising what I was doing I quickly mimicked the positioning of the Norman Hewers using a firewood sawhorse and this stoped "the bounce". I also found that it was easier to hew from the pith down to the outside edge to create the first rough pass flat surface i.e. removal of the high spots and then the post was flipped and this process repeated on the other side of the post pith. I then removed all the sap wood along the split edges forming an arris thereby leaving one semi round face and three flat faces. If I had needed to remove the semi round face then I would by default have created a rafter and so by process of experimentation it seems relatively easy to rediscover the old techniques for making components.
One February morning as the snow was melting on Royalston Common in Northern Massachussetts I gathered up some wind blown white ash seed and brought this home with me to see if they would germinate. They did indeed and these seeds soon turned into healthy saplings which I grew on in pots for 5 years or so before eventually planting them out in my woodland alongside their English cousins. I am hopeful that in due course and long after I am gone someone walking the woodland will hopefully chance upon these American White Ash trees and wonder ?