Late 20th century warming has weakened the relationship between temperature and growth in northern forests. This loss of sensitivity to temperature, often attributed to drought stress in warmer regions of the boreal forest, has also been observed in cool, mesic environments, where warming‐related growth declines are poorly understood. We used annually resolved ring‐width and carbon stable isotope (δ 13 C) chronologies from whi...

Climate warming in recent decades has negatively impacted forest health in the western United States. Here, we report on potential early warning signals (EWS) for drought‐related mortality derived from measurements of tree‐ring growth (ring width index; RWI) and carbon isotope discrimination (∆ 13 C), primarily focused on ponderosa pine ( Pinus ponderosa ). Sampling was conducted in the southern Sierra Nevada Mountains, near t...

The negative growth response of North American boreal forest trees to warm summers is well documented and the constraint of competition on tree growth widely reported, but the potential interaction between climate and competition in the boreal forest is not well studied. Because competition may amplify or mute tree climate‐growth responses, understanding the role current forest structure plays in tree growth responses to clima...

Increment cores from the boreal forest have long been used to reconstruct past climates. However, in recent years, numerous studies have revealed a deterioration of the correlation between temperature and tree growth that is commonly referred to as divergence. In the Brooks Range of northern Alaska, USA , studies of white spruce ( Picea glauca ) revealed that trees in the west generally showed positive growth trends, while tre...

The Arctic has experienced rapid warming and, although there are uncertainties, increases in precipitation are projected to accompany future warming. Climate changes are expected to affect magnitudes of gross ecosystem photosynthesis ( GEP ), ecosystem respiration ( ER ) and the net ecosystem exchange of CO 2 ( NEE ). Furthermore, ecosystem responses to climate change are likely to be characterized by nonlinearities, threshold...