Learn Russian: Дерево упало от сильного ветра, так что пожарные отступили. - The tree fell from the strong wind, so the firefighters stepped back.

While both express cause, от is naturally used for involuntary physical reactions or uncontrollable natural forces like wind (ветер). Из-за is often used for obstacles or human actions that cause a negative result.

Could I use поэтому instead of так что to mean 'so'?

Yes, but the grammar differs. Так что is a conjunction that smoothly connects a result clause in the same sentence. Поэтому is an adverb (therefore) that usually starts a new sentence or pairs with the word и to link clauses.

How would we apply this lesson's стоило ... как construction to this sentence?

You would put the tree in the Dative case and use the infinitive: Стоило дереву упасть от сильного ветра, как пожарные отступили. This adds the meaning of an immediate trigger: 'As soon as the tree fell, the firefighters stepped back.'

How does the prefix in отступили build its meaning?

The root relates to ступить (to step). The prefix от- shows movement away from something. Combined, отступить means to step back, withdraw, or retreat from danger.