It is crafted using two Figs and a Glommer's Goop. It can be used to enrich Knobbly Trees to eventually turn them into Above-Average Tree Trunks, and can also be used on any Tree to instantly grow it by one stage. It can also serve as Fertilizer, restoring 8 Growth Formula, 32 Compost, and 8 Manure to farm soil. Wormwood can fertilize himself with it to heal 2 + 32 (over 32 sec) health, and trigger his blooming. Additionally, it can seal the leak on a Boat without leaving any patch, doing so will also repair 20 for Boat.
Tips
Tree Jam is the only way to completely remove leaks on a boat, as Wavey Jones will attempt to remove Boat Patches and Trusty Tapes at 25% Sanity.
Knobbly Trees not fully grown after sprouting from a Knobbly Seed will advance their growth as well, rather than be enriched. To avoid the potential waste of a Tree Jam, make sure that the Knobbly Tree is at its final stage before attempting to enrich it.
Gallery
Tree Jam Dropped Sack
Used
Tree Jam concept art from Rhymes With Play #282.[1]