What limits how tall a tree can grow?

Water. A tree drinks by evaporation from its leaves pulling on unbroken columns of water held together by the molecules' attraction to each other - there is no pump anywhere. Above roughly 120 metres, the tension needed to lift water that far would exceed what those columns can bear, and they cavitate: an air bubble forms and the chain breaks.

The tallest known trees sit just under that. Coast redwoods pass 115 metres, and measurements on the topmost foliage of the tallest specimens show leaves that are already water-stressed and physically different in shape from those lower down - shorter, stiffer, less efficient. The tree is arguing with physics near the top rather than with its neighbours.

Everything else that might limit height turns out not to bind first. Structural strength is not the constraint; nor is getting sugars down; nor wind, mostly. It is the plumbing, and the limit is roughly the same for any tree anywhere - which is why the tallest species on very different continents converge on a similar ceiling. Coast redwoods also cheat slightly by absorbing fog directly through their needles, which is why they only grow in a narrow coastal belt.