Bark is a large reservoir for water storage in forest ecosystems. It is directly exposed to wetting during rainfall and reacts to changes in relative humidity via absorption or desorption of water vapor with the atmosphere. The proportion of rain water that can be absorbed and stored in bark compared to the amount that makes it to the forest floor and the tree's roots depends on the species. In this way, bark influences the water cycle of individual trees and entire forests. Differences in bark structural traits such as density, porosity, hydrophobicity (external water repellency), and hydroscopicity (internal water retention) vary among directly influence the water storage capacity of a tree. This research spans forest types across continents to understand:

1. How structural and physical differences of bark among species impact bark water storage.

2. How these differences are manifested under varying rainfall and drying regimes.

3. How these differences change along the tree trunk, across age classes, and across forest management regimes.