Effect of lightning on trees. 19th century artwork showing the effect of a lightning strike on a fir (Abies sp.) tree trunk. When a lightning bolt strikes a tree, very intense current flows through the sap making it boil instantly. The energy released blows strips of wood and bark from the tree and is often enough to split a tree along its length or even to destroy it. Illustration from 'Memoire sur les effets de la foudre sur les arbres et les plantes ligneuses et l'emploi des arbres comme paratonnerres' (Memoire on the effects of lightning on trees and woody plants and the use of trees as lightning conductors, 1868) by the Swiss physicist Daniel Colladon (1802-1893).