A line of massive elms (Ulmus sp.) exists quite nearby to my place of work, and I thought I’d take a look at them today during a break as some have, as they have hollowed-out over time, fallen. On top of hacking off quite a large bumblebee in a hollow stump, I came across a fine example of a Ganoderma (suspected G. australe) that had existed prior to its host elm falling, and following its change in orientation, re-grew in response to the new direction of gravity acting upon its structure. In short, this is known as geotropism (or gravitropism), and the pictures probably explain it easily enough.
Arboriculture 