How old are big oaks?

Determination of the exact age of old trees is rarely possible due to hollow rot and decomposition of the tree rings close to the pith.

Reconstruction of age distribution for the largest oak trees in Scania suggested that 95% of this population is older than 200 years with the majority of the trees expected to be between 400 and 700 years old. However, the age distribution of 17 large old oaks (diameter > 1 m) with pith preserved indicated that oak does not commonly exceed an age threshold of 500 years (Figure).

Figure. Conversion of diameter and ring width distributions into age distribution of big oaks in Scania. Dots refer to the tree ring dated oak trees with pith present or pith being located within a few rings from the oldest sampled ring (Niklasson et al, unpublished; Drobyshev et al., unpublished). Solid line represents mode of ring width distribution. Dotted lines refer to the upper 95% and the lower 5% of the ring-width distributions and were obtained by calculating average 95 and 5% limits of ring width distributions for single big trees (n = 69).