Tree rings are a good place to start thinking about how climate researchers get information about past climates.
In certain cases, trees can live for many hundreds of years and in an extraordinary case, like the bristlecone pine, thousands of years!
A tree's growth rate changes in a predictable pattern throughout the year in response to seasonal climate changes, resulting in visible growth rings.
Dendrochronology is the study of climate change as recorded by tree growth rings.
Each year, trees add a layer of growth between the older wood and the bark.
This layer, or ring as seen in cross section, can be wide, recording a wet season, or narrow, recording a dry growing season.
Because the rings are basically recording a good growing season or a bad growing season, they are indirectly recording more than just moisture.
The phenomenon of tree rings and their relationship with wet and dry years had been noticed before Douglass.
There is a brief note in one of Leonardo da Vinci's notebooks, and Charles Babbage in 1837 came up with the same idea.
Dendrochronology has three main uses: , -logia) was developed during the first half of the 20th century originally by the astronomer A. Douglass, who founded the Laboratory of Tree-Ring Research at the University of Arizona. He expected changes in solar activity would affect climate patterns on Earth.
The climate would be recorded by tree-ring growth patterns.
In his Trattato della Pittura (Treatise on Painting), Leonardo da Vinci was the first person to mention that trees form rings annually and that their thickness is determined by the conditions under which they grew. S., Alexander Catlin Twining (1801–1884) suggested in 1833 that patterns among tree rings could be used to synchronize the dendrochronologies of various trees and thereby to reconstruct past climates across entire regions.
During the latter half of the nineteenth century, the scientific study of tree rings and the application of dendrochronology began.
The study of tree rings is called dendrochronology.