An Imperial mixing vat of wroshyr sap. Wroshyr sap, referred to by the inhabitants as "tree blood", was a vital substance found within the wroshyr trees of the planet Kashyyyk. The native Wookiees were able to distill this substance into sapwater, a mildly sweet beverage that they favored over rainwater. In addition to sapwater, distilled wroshyr sap, combined with wroshyr leaves, served as a base for the creation of various chemicals and oils.
Following the Galactic Empire's occupation of Kashyyyk, they also began the process of refining wroshyr sap at an Imperial Refinery to extract a reactive chemical element. However, their methods were ecologically damaging. Reports indicated that the refinement of each barrel of sap resulted in the disposal of over 200 metric tons of industrial byproducts into nearby waterways.