Multiple changes - see details:

Rewrote how beech trees are replacing default trees so that they work
properly with old recipes.  Now we redefine the old wood nodes to force them
to use new textures and new descriptions, but retaining the old node names
so that they work with everything.  This means the former moretrees:beech_*
nodes have been discontinued and aliased back to the default nodes.

Added stairs/slabs for all trunks and wooden planks - this means that
moretrees now depends on moreblocks.

Use nodeupdate() instead of dig_node() for leafdecay lighting/falling updates.

Increase palm tree leaf decay radius from 8 to 12.