The first embodiment of the tool for girdling the trunk of a tree includes an elongated and horizontally disposed handle having first and second ends. The tool also includes a horizontally disposed cutting blade support having a first elongated arm portion and a curved arm portion. The first elongated arm portion is pivotally connected to the handle intermediate the lengths thereof. A linkage also pivotally connects the second end of the handle to the first end of the first elongated arm portion. A cutting blade carriage is selectively movably secured to the curved arm portion to compensate for various tree trunk diameters. A second embodiment of the tool includes an elongated handle which is adjustably secured to a cutting blade support which has a cutting blade secured thereto which is forced into engagement with the tree trunk by a spring arm.
