Cross section of oak wood, showing every reason that made an oak tall and strong. The large pores are vessels that are responsible for transporting (more accurately, pumping/pushing) water from the root system to the tip of the tree. The densely packed purple dots are stained lignin in the cells walls. During early wood development, once lignin is deposited in the cell wall, these cells (called “fiber cells”) will die, but the hardened cell walls remain there to support the weight of the tree for years and decades. And time, is marked by the growth ring boundaries – the thin horizontal lines adjacent to the large vessels.

Contributed by Min Ya, a second year graduate student in the Organismal and Evolutionary Biology program at Harvard University, and our Featured Artist for April 2017. To meet Min Ya and see more of her art, click here.