The deadwood servants created by the hallow could be harvested for valuable materials, even while alive, and the pores from the hollow itself could be collected. Doing so required [Appraisal] to recognize the ingredients, understand their properties and harvest them. The entire process required at least one hour of strenuous activity, something a Deadwood Hollow rarely tolerated peacefully.
The pouch of [Rotting Spores] was mostly an ingredient for poisons and antidotes. At the same time, the sap from the Deadwood Servant was a valuable ingredient in relation to concoctions that affected sleepiness and charms.
Ren collected those materials while he could, but he did [Teleported] forward so he could escape Deadwood Hollow's tight grip while his [Touch of the Golden Sun] and [Gravity Zone] were still in effect.