Analysis of Vegetation Water Content in Temperate and Boreal Forests

Retrievals of soil moisture from space are limited when vegetation is present, as the vegetation water content (VWC) dominates the soil moisture signal. This interference by vegetation results in the exclusion of soil moisture data in forested regions when vegetation water content is greater than 5 kgm-2. This presentation will focus on how vegetation water content is calculated in temperate and boreal regions to understand the seasonality of this interference. Currently, VWC is calculated based on canopy water content and stem water content. Part of the stem water content is the stem factor, a pre-determined value that is applied to all vegetation of similar types. However, another method for calculating vegetation water content incorporates the average heights of trees, potentially providing a more accurate representation of VWC amounts. After comparing the two methods in a temperate and boreal forest, results show that the temperate forest was more sensitive to average tree heights and by accounting for tree heights of different regions, more accurate vegetation water content values could be calculated. Overall, this suggests that methods for calculating vegetation water content could be revised in order to better represent that amount of water that is in plants and trees.