Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
A pressure chamber is used to record how much pressure is required to squeeze water out of a small sequoia branch – a measure of the drought stress experienced by the sequoia. (Photo credit: A. Ambrose, UC Berkeley)
