When it comes to wild-harvesting edible and medicinal plants, I've heard blanket rules regarding how much plant material can be ethically removed from a site. For example:

"Take no more than 30% of a stand of wild plants."

These rules may be a useful starting point. However, as we learn more about medicinal plants' behavior and native status in our ecosystem, harvesting practices should become more refined.

When I encounter spicebush (Lindera benzoin) growing under hardwoods, I feel a little thrill. I pluck a leaf, crunch it between my fingers, and inhale the aroma deeply. Spicebush possesses one of the most pleasantly intoxicating scents I have ever experienced. The fact that this shrub is native to my home region makes it particularly sweet.

Once upon a time, humans ate a diverse array of bitter leaves and roots from the wild plants surrounding us. We enjoyed the benefits of their vitamin and mineral content, fiber, antioxidants, prebiotics-- and also their bitter constituents. In fact, our gastrointestinal system (and other systems) developed a complex relationship with bitterness over time, and came to depend on this flavor for healthy functioning.