Identifying Threshold Temperatures Associated with Bristlecone Pine Growth Signals in the Great Basin, USA
Abstract
The interpretation of ring-width patterns in high elevation Great Basin bristlecone pine is hampered by the presence of sharp ecophysiological gradients that can lead to mixed growth signals depending on topographic setting of individual trees. We have identified a temperature threshold near the upper forest border above which trees are limited more strongly by temperature, and below which trees tend to be moisture limited. We combined temperature loggers and GIS modeling at a scale of tens of meters to examine trees with different limiting factors. We found that the dual-signal patterns in radial growth can be partially explained by the topoclimate setting of individual trees, with trees in locations where growing season mean temperatures below about 7.4°C to 8°C were more strongly associated with temperature variability than with moisture availability. Using this threshold we show that it is possible to build both temperature and drought reconstructions over the common era from bristlecone pine near the alpine treeline. While our findings might allow for a better physiological understanding of bristlecone pine growth, they also raise questions about the interpretation of temperature reconstructions given the threshold nature of the growth response and the dynamic nature of the treeline ecotone over past millennia.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMPP41C2279W
- Keywords:
-
- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 1620 Climate dynamics;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGEDE: 4928 Global climate models;
- PALEOCEANOGRAPHY