To me, one of my favorite places to get a bonsai, is from the wild. They often have more character, with more twists, bends and more mature bark, then some of the nursery trees. This is because they have struggled to survive in the wild. Also, its a bit like hunting, you have to find them, which can be the biggest challenge, because suitable trees can be well hidden in spots that can be hard to access.
Yamadori means collecting trees in the mountains, in Japanese. This has been taken to the extreme in some areas, such as the mountains of Japan, where wild trees can be hard to find. You need to collect responsibly. Part of that responsibility, is to only collect what will survive the process. Don’t take any trees that don’t have a good root system, or one that goes deep under some rocks, making its removal a death sentence. Another concept of responsible tree collecting should be replanting.
I believe all Yamadori collectors should replant at least 2 trees for each one they take. It can be as simple as getting some seeds or cones from that same species you are taking, and planting those in the same area you just harvested from. I call this concept Yama modoshi.
this means replanting the wild. If we are going to continue to have a future of finding trees in the wild, and the bonsai artist of the future have the same chance as well, we need to adopt this concept.