A 150 year old tree is a snapshot of the annual weather over its relatively short life.
It would be more relavant IF they did this with some of the Bristle Cone pine trees that are thousands of years old.
from the google:
“The oldest bristlecone pine tree in the world, Methuselah, is located in the White Mountains of Inyo National Forest in eastern California. The tree’s exact location is kept secret to protect it from vandalism.
Explanation
Age
Methuselah is estimated to be over 4,856 years old. Its age was determined by measuring core samples taken in 1957.
Location
Methuselah is located in a remote area between the Sierra Nevada range and the Nevada border.”
I know exactly where that tree is in the White Mountains, I first visited it over 50 years ago before it's location was withdrawn from the public.