I've posted about the association between hackberry and mesquite I've observed before (specifically, individuals of each species growing right next to each other, to the point they'd probably form a natural graft if they were the same species), but this is an extreme example. The green leaves at the top of the first picture are the hackberry's; you can see the straight edge where it's been chopped short, but losing their top is only a temporary setback for these trees. This hackberry is actually growing inside the mesquite! It's the the smoother gray wood visible in the second picture, contrasting with the heavily textured mesquite bark. Other than this central hollow, the mesquite was intact, which makes me suspect the hackberry germinated in there. Unfortunately, we were pressed for time and I couldn't examine it more closely, but we'll definitely come back to take a better look at some point.
