Records of fires from many fire-scarred trees can be compared to provide a history of the frequency, extent, and character of this process through time. Since the events can be dated to the exact calendar year, and in some cases to the season, records from one area can be compared to records from any other, as well as with independent historical records and reconstructions of past climate. The dominant tree species have elevated canopies and thick fire-resistant bark. They can easily survive low-intensity surface fires that were common in past centuries. These characteristics allow adults to survive all but the most intense fires, and their seedlings to colonize areas cleared of forest litter and potential competitors.
Sequoias are also excellent sources of information on the history of fires in their vicinity.
Surface fires often scar trees around the base, wounding small areas of tissue that are subsequently grown over, enclosing the wound within the new wood. With individuals able to live more than 3,000 years the trees can contain many centuries of environmental history within their rot-resistant wood. Wood sections cut from down sequoia logs and standing snags were used to reconstruct the fire history in five sequoia groves for the past 1,500 years. Due to the remarkable preservation of the wood a very detailed history was compiled with seasonal resolution and information on fire extent and severity for the groves. The detailed fire histories reconstructed for the groves show that fire was a frequent and pervasive influence in these forests for the entire length of the record.