Editing Proxy (climate) (section)

===Tree rings===
[[Image:Tree rings.jpg|thumb|left|Tree rings seen in a cross section of a trunk of a tree.]]
{{main|Dendroclimatology}}

Dendroclimatology is the science of determining past climates from trees, primarily from properties of the annual [[tree rings]]. Tree rings are wider when conditions favor growth, narrower when times are difficult. Two primary factors are temperature and humidity / water availability. Other properties of the annual rings, such as maximum latewood density (MXD) have been shown to be better proxies than simple ring width. Using tree rings, scientists have estimated many local climates for hundreds to thousands of years previous. By combining multiple tree-ring studies (sometimes with other climate proxy records), scientists have estimated past regional and global climates (see [[Temperature record of the past 1000 years]]).