HikeArizona.COM

A new study from researchers at the University of North Carolina at Chapel Hill has revealed the key factors that determine where trees can grow at the highest elevations across the globe. By compiling the most comprehensive dataset of alpine treelines to date, more than 2,000 records worldwide, the research team uncovered a dual control system that explains why treelines form where they do, and which tree species dominate them.

https://phys.org/news/2025-08-global-tr ... c%2Fnature

@Pivo
Interesting, I myself like to track the saguaro "tree" line here in AZ.

TLDR: trees can only grow where there is enough water, and it's not too cold. Shocking study results!

What happened to the old rule of timberline typically being where the average temp during the two warmest months of the year drops below 55 F ? If a region gets warmer, timberline gets higher.

@LindaAnn you should ask Mr. Humboldt! —though I think he said 10 non-patriot units ;)