For those interested in climates past and present, trees do more than absorb carbon dioxide. With good reason: tree rings enable reliable climatic reconstruction for most parts of the world, especially in temperate regions where the contrast between seasons usually yields more discernible rings.

How are tree rings reliable?

Climate scientists compare the tree growth records to local weather records. For locations where a good statistical match exists between tree growth and temperature or precipitation during the period of overlap, the ring widths can be used to estimate past temperature or precipitation over the lifetime of the tree.

How are tree rings evidence of climate change?

The color and width of tree rings can provide snapshots of past climate conditions. For example, tree rings usually grow wider in warm, wet years and they are thinner in years when it is cold and dry. If the tree has experienced stressful conditions, such as a drought, the tree might hardly grow at all in those years.

Is it OK to put rock around trees?

Rock mulch protects roots and trunks, conserves water and decorates the area around trees. Landscaping with rocks around trees improves the yards appearance with a natural material. Almost half of a households water use goes for watering grass and landscaping; mulching with rock conserves water.

How far back can tree ring dating go?

Each ring marks a complete cycle of seasons, or one year, in the trees life. As of 2020, securely dated tree-ring data for the northern hemisphere are available going back 13,910 years.