Trees can tell stories about past climates. Scientists can decode the pattern of a tree’s growth rings to learn which years were warm or cool, and which were wet or dry. Scientists combine the ring patterns in living trees with wood from trees that lived long ago, such as the wood found in old logs, wooden furniture, buildings like log cabins, and wooden ships, in order to build a longer historical record of climate than the lifespan of a single tree can provide.
You can decode tree ring data to learn about past climates using the simulation below. Line up tree ring patterns to reveal temperatures in the past. The simulation has two versions. The standard version is the best place to start. The custom version for schools in the United Kingdom was created to go along with a specific curriculum. It has a longer timeline and includes information about some historical events.
The process scientists use to build a climate history timeline has an extra step that, for the sake of simplicity, is not represented in this simulation. When scientists decode long climate records from tree ring patterns, they don't physically line up the tree core samples next to each other. Instead, they make graphs called skeleton plots for each sample. They combine the skeleton plots from many samples to build a climate history timeline.
Data source for this simulation
The tree ring data in this simulation is from oak trees in southern England. The data, from the UK Oak Project, was collected from living trees, logs in bogs, beams and rafters in old buildings, old wooden furniture, and wall paintings in a farmhouse dating back to 1592. One sample came from the windlass - the wooden crank used to raise and lower a castle's gate - of the Byward Tower in the Tower of London.