Although trees, which generally have long lifespan, are exposed to many risks of occurring mutations due to DNA damages, they can live long time. We focused on the DNA repair as a mechanism to suppress the occurrence of mutations, and examined whether trees have high DNA repair ability. We compared copy number of DNA repair genes within 144 gene families across 55 plant species with different life forms using PLAZA database. We also analyzed seasonal expression patterns of 129 DNA repair genes among three Fagaceae species.
As a result of clustering based on the copy number of genes, there were two different clusters of high and low copy numbers. Tree species were contained in the cluster with high copy number, but not in the cluster with low copy number. Moreover, trees had higher copy number of repair genes of DNA double strand breaks and DNA damages due to oxidation than perennial and annual herbs. The expression of a repair gene of DNA double strand breaks was high in summer.  
Our results suggest that trees would have a high DNA repair ability, especially against DNA double strand break and DNA damages due to oxidation.