Large burl on a paper birch (betula papyrifera). The crown gall disease is caused by agrobacterium tumefaciens. Spruce-fir-northern hardwood forest.

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Size: 2864px × 4474px
Location: Kettle Pond State Park, Groton, Vermont
Photo credit: © Rasvan ILIESCU / Alamy / Afripics
License: Licensed
Model Released: No

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