Spalted

Patterns in felled trees caused by fungal infestation that penetrates the heart wood. The black lines demarcate zones created by different species of fungi erecting barriers around their territories. The primary colonizers arrive first and establish themselves and then have to defend against secondary colonizers, producing this map-like patchwork effect. Spalted wood is much in demand by woodworkers to give a patterned effect to the finished product, for example guitars and bowls.

I found these patterns in the trunks of felled sycamores that are being replaced by a mixture of trees.