Building a tree observatory
The simple physical dimensions and slow temporal dynamics of trees present unique challenges for scientists studying their growth, behavior, health, reproduction, and management. The majority of a treeRSQUOs interaction with the biotic and abiotic environments take place either in the tree's canopy or underground, beyond easy access by researchers. The simple act of obtaining 1) physical collections of relevant biotically active samples, and 2) repeated and continuous observations of physiology, growth, and behavior remains a major hurdle. Most current research targeted at the individual tree has focused on obtaining physiological measures from the main stem, like diameter growth and general water dynamics, particularly sap flow. Sap flow is a fundamental aspect of tree physiology and a necessary physiological baseline, much like blood pressure in animals. Given the fundamental shift in global cycles presented by the Anthropocene, we strongly advocate a multi-faceted and holistic 'tree observatory' approach through the comprehensive and simultaneous collection of observations from many parts of individual trees and an integrated, organismal-level analysis. The tree observatory will require the adaptation and invention of efficient, autonomous, ideally self-propelled, tools and sensors through strong engagement with engineers and computer scientists, similarly to the tremendous achievements of NASA's planetary exploration programs. We would emphasize that the majority of technological innovation in tree science has been oriented towards the forest while relatively little has focused on the dynamics of individual trees. Ultimately, the tree observatory would provide 1) understanding of how the tree integrates whole organism responses to environmental change and biotic challenges and their time scales, 2) a resource to identify early warning signs of decline or disease, and 3) a testing ground for new tools for tree science that could be deployed widely and cheaply.
Cannon, C.H., Scher, C.L., Gao, A., Khan, T. and Kua, C.-S. (2018). Building a tree observatory. Acta Hortic. 1222, 85-92
sap flow, simultaneous observations, organismic biology, arboriculture, drones