Strangler Vines
As the Verdant Growth spreads across the ground, Strangler Vines will sprout from the grass at the roots of trees. Despite the ominous name, Strangler Vines aren't directly harmful to players. They will, however, overgrow and choke out trees. Mature trees will grow Poison Ivy and Strangler Tendrils hanging from their leaves. These are used for a variety of purposes, and should be collected whenever convenient.
While it may take some time for Strangler Vines to overgrow trees, overgrown trees contain a lot more wood as well as other valuable resources. Also, Strangler Leaves can be used as sources of vines, poison ivy, and thorns.
Heads up!
Strangler Vine growth is random, so it's difficult to predict what shape a tree will produce! Sometimes, identical trees will be overgrown in entirely different ways.
The outer layer of an overgrown tree is composed of Strangler Vines; these can either be placed on logs to start a new Strangler Tree, or crafted into Strangler Logs. Leafy Strangler Vines act identically, and can substitute for Strangler Vines in the recipe. The only difference is that Leafy Strangler Vines have leaves.
Strangler Wood
The Strangler wood set has a rustic and splintered look.
Heartwood
Sometimes, an overgrown tree will only have a thin outer layer of Strangler Vines, and the wood underneath will survive. More frequently, however, an overgrown tree will be formed of several layers. Just beneath the Strangler Vines is a layer of Strangler Logs and Strangler Wood. Inside that - next to the original trunk of the tree - are valuable Heartwood Logs. These should always be collected; they can be crafted into useful equipment with the mining speed of iron, though with low durability.
Heads up!
You may rarely find Imbued Heartwood Logs inside overgrown trees; these are covered with many vivid green veins, and are key to crafting imbued heartwood equipment. Before you mine it, think about what might have caused the tree to secrete such an excess of energy!
Aside from their uses in crafting equipment, Heartwood has a complete wood set in bright green. It is an excellent decoration and a good way to display your wealth and lumbering skills.