Any ordinary thunderstorm produces lightning, which certainly can be dangerous. However, lightning has a beneficial side-effect that few people recognize. However, the nitrogen in the air is in a form that plants cannot use directly. Furthermore, lightning-caused forest and prairie fires are increasingly being recognized as important components of a healthy ecosystem. Strong winds from thunderstorms can do terrible damage to buildings and other artificial structures.
Winds tend to seek out the weak and old parts of a forest, breaking limbs and uprooting some trees.
Within these gaps in the forest, new plants can prosper that would otherwise be shut out by the impenetrable forest canopy. The most extreme thunderstorm winds, of course, are tornadoes. It has been found that in drought years, hurricanes are often the process that breaks the drought along their path. Although at landfall, hurricanes do their worst damage, they often survive inland for great distances as producers of heavy rains. As with thunderstorms, it's possible that the drought-breaking rainfall brought by dissipating hurricanes can offset most of the damage they do.