A history of varying methods for determining tree age in Estonia with emphasis on oak

This paper explores the history of age detection of trees, especially the age history of oak trees, throughout two centuries in Estonia. It was already in the beginning of the 19th century when relations between the size and age of oaks in northern Latvia (previous Livonian province) were described. The paper explains how the species concept of Quercus robur developed over time in the past and points out discussions on the existence of two varieties Q. robur L. var. tardiflora Czern and Q. robur L. var. praecox Czern. It also states that thanks to the use of the increment borer, the first dendrochronological studies were carried out in Estonia in the 1920s. Dendrochronological research in the Soviet Union began in the 1950s with Lithuania being the leading country in the field headed by Teodaras Bitvinskas. In Estonia, research was continued in the 1960s until now. The paper takes a look at the life of Mart Rohtla who introduced the method of determining tree age according to tree bark, presents his standpoints on oaks and critically assesses these. A comparative assessment is given on the ages of oak and lime trees found according to the tree-ring method and bark increment method. The great ages of the oaks and limes found by applying the bark increments method are doubted and considered unreliable. However, the age of the surface layers of the bark of oaks and limes needs clarification in the future.