Mixed_deciduous_forest_Catalonia (IMAGE) Aarhus University Caption The composition of tree species, as here in Catalonia, is linked to climate changes over the past 21,000 years. Credit Photo: Auró, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons Usage Restrictions Credit must be given to the creator. Adaptations must be shared under the same terms. License CC BY-SA Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.