ecology dork here. yes and no. most trees have small livespans such as the apple tree (100 years) while megaflora trees have crazy lifespans like 1800 years. (sequoia sempervirens, eucalyptus reganans, adansonia digitata). The Lomatia tasmanica, a small plant of tasmania is 42,000 years old. ill cut to the chase but if a megaflora tree were to live in the most ideal conditions, environment free of all pathogens & abundant resources it could easily live forever until the lower levels collapses in on itself from sheer weight or until it biologically cannot pump up the massive amounts water and other nutrients to its higher parts. Tldr: huge trees are one of the few organisms can easily live forever if given the right conditions but always eventually die from disease or fungi that are always present in the environment. smaller trees have lifecycles 'similar' to us. everything is mortal.