Ash for stays St Clements Stays are glass fibre. The design was trialled at Great St Mary's and has yet to break and so far so good at St Clements. The ringing centre is being used to teach a lot of Ring for the King learners so the stays are getting a good test.
There is clearly no magical properties to ash its just a tradition, what matters are the mechanical properties of flexibility, fatigue and fracture resistance. However if you plot the variability of different types of wood (available from US variant of the forestry commission) you find ash is a pretty consistent wood and hence safe to use, other woods, such as some softwoods, have a lot more variability so they may work or they may not,