In article , Setsuna
writes
Hi all,

I thought this might be the best place to ask...

I'd like to figure out the size of root systems of two trees on my
property, one is an apple tree and the other is an old ash tree that's
taller than my 2 storey house!

Obviously, I'm not looking for exact measurements here :-) but I'd
like to figure out a ballpark figure.

Is there a way of estimating that?

Rule of gardener's thumb suggests that there is about as much root as
there is branch in total. Roots tend to spread more outward than
downward though, where branches take the shape of the tree species, or
according to how they are pruned.
--
Alan & Joan Gould - North Lincs.