The age of monumental trees. A case study of Juniperus thurifera L. in Spain

• Main Authors: Mar Génova Fuster, Enrique Sadornil
• Format: Article
• Language: English
• Published: Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria 2020-11-01
• Series: Forest Systems
• Online Access: https://revistas.inia.es/index.php/fs/article/view/16172

Aim of the study: To provide tree-age estimation of monumental Juniperus thurifera trees based on dendrochronological methods. Area of study: “Sabinar de Calatañazor” Nature Reserve (Calatañazor, Soria, Spain), a monumental forest of Juniperus thurifera traditionally used for grazing. Material and methods: Tree-ring width analysis of increment cores and four different methods for estimating the age of each of the trees analysed. Main results: Our estimates suggest that most of the trees in this Nature Reserve with a radius greater than 30 cm are over 300 years old. Moreover, the discussion on the constraints and accuracy of each of the four tree-age estimation methods employed can be helpful in future studies of age in many monumental trees. A well-replicated local chronology, ranging from 1738 to 2012 (275 years), was also established for its use in reconstruction studies related to management, past events and climate change. Research highlights: This study involved analyzing many trees with high percentages of rings that had disappeared as a result of rot. In this case, the age estimation models based on the classical hypotheses of constant growth in radius or basal area, as well as a new estimation method based upon biological behavior and considering two growth stages (juvenile and mature), are the ones that provided the most reliable estimates. On the contrary, regression models are less recommendable, due to being less accurate. Keywords: Dendrochronology; tree-age estimate; rot, growth stages; management and conservation measures.