Birch tree sap! (tapping)

[T-oddity]

I've done a fair bit of tapping birch trees, even on one occassion for a specialist confectionary maker. by all means have a go at this to learn how to do it, but please do not do it on a large scale, invariably the tree will continue to weep even if the hole is well plugged and many will become infected by fugal attack which will kill the tree. This was brought to my attention a year a so ago and as a consequence I checked out many of the trees I had previously tapped and found it to be the case, so have stopped tapping.