Does it make a sound?
Or - as I was cycling home last night looking nervously% at the trees as I passed*, I was wondering - if one falls does it crack and fall slowly as it tears apart giving a vulnerable cyclist time to take evasive action - or does it just thud down like 10 tons of bricks?
Does anyone know?
*one section being particularly nervous under 1/2 mile of tree tunnel.
%I know - an irrational fear of falling trees compared to the (probably) much higher risk of bad drivers that I no longer worry about.
Speaking as an Arborist, I would say that it depends. Both on the condition of the tree, and the species of the tree.
Beech trees (Fagus sylvatica), have a documented predisposition for throwing limbs. Infact among some woodspeople there is a superstition not to say nasty things or swear under a beech tree lest it may here you and throw a branch at you. The conditions under which the limbs tend to fall off are due to rain levels and related conditions, which for the life of me I can't remember right now. If one falls, chances are you will hear the crack and then notice the large lump of wood landing shortly after.
However, where this gets blurry is that the branch may have gone crack long ago, fallen a bit, and had it's fall broken by a lower limb. Here it then sits until such time as the movement of the tree in the wind puts it in a position where that final gentle shove pushes it off the side and *splat*. This will be silent, apart from any small branches it hits on the way past.
As for if a tree falling makes a sound. Oh yes. for a tree to fall typically the ground needs to be saturated such that the roots are loosed, even so there's likely to be tearing of smaller roots and creeking noises as the root plate tilts up. It makes a horrible noise that you don't want to hear.
For a tree to break and not lift up with it's root plate is very rare, and usually implies that there has been some structural weakness (such as included bark at a fork), but this is going to require substantial inputs of energy (read wind) to make it go split.
So to summaries, parts of tree (tho large in scope) can fall relatively silently. But a whole tree is likely to make a horrendous noise giving you just enough time to turn and face your doom before it squashes you.
HTH.
J