It is a common misconception that the bark of a tree will dull your chainsaw. While it is true that bark can be abrasive, it is not nearly as abrasive as dirt, sand, or other materials that can quickly wear down your chain. In fact, most people who use their chainsaws regularly will only need to sharpen their chain once or twice a year. Even if you do manage to dull your chain by cutting through bark, it is easy to sharpen it yourself with a sharpening stone or file.