Ganoderma applanatum Artist's Conk
Ganoderma has very tiny pores. Look at the diameter (right) and compare to the length of the tube (left). The spores have to be discharged from any point on the tube and must fall by gravity the entire length of the tube and 'escape' through the pore at the bottom of the tube to be carried off by the wind. Consider the logistics and technical requirements to align the tubes exactly vertically so that the spores do not touch the sides of the tube during this drop.