Trunk layers
Exclusively classical!
One major difference between trees from the classical definition (conifers and hardwoods) and from the ones added to the Hallé definition (Plant, usually high (at least 5 meters), which has a single trunk and branches which appear at a certain height above the ground.) (palms, tree ferns, bamboos, etc.), is their trunk. Trees from the classical definition all produce secondary growth in their trunk, and present similar tissue layers.
Trees exclusive to the Hallé definition have very varied trunks. To describe them would be too complicated, almost having to explain them individually: bamboo culms (Hollow stem of bamboo.), palm stipes (False trunk of palm trees.), tree fern rooted trunks (The section of root nearest the crown from which multiple roots emerge.)... So, the trunks presented here exclusively represent trees from the classical definition, conifers and hardwoods.