Poplar wood - inside out: High-resolution spatial, cellular, and pseudotime projections from cambial transcriptomes

The lifestyle of trees may seem sedentary, but behind the scenes, various meristems are busy stacking layers of cells in different directions, which allows trees to soar to great heights and girths. Procambial cells are formed continuously during "primary growth" very close to the shoot apex, guaranteeing the continuity of the vascular system throughout the stem and vertical growth. Primary growth turns, by definition, into "secondary growth" with the advent of the vascular cambium. In tree species, like poplar, vascular cambium is formed within the first few internodes, initiating the "secondary growth" and expansion of the stem to generate "wood," one of the largest sources of biomass on our planet.