An animation explaining dendrochronology in six steps: (1) reading a tree's hidden diary; (2) an increment borer takes a slender wood core without cutting the tree down; (3) proper technique — position square to the trunk, hold steady, turn slowly; (4) extract the core and keep its order, bark end to centre; (5) each growth ring equals one year, so counting rings counts years; (6) wide rings mean fast growth and narrow rings mean slow growth, and matching ring patterns across many trees (cross-dating) builds a calendar record spanning centuries.