Rarely a serious problem. Look-alikes: Jumping oak gall, tubakia leaf spot, oak leaf blister, other fungal leaf spots. Jumping oak gall Brown leaves appear on trees in the white oak group in late spring. Severe infections may cause the leaves to turn black, curl up and fall. On the underside are brown galls with the larva of a small wasp inside.
Volcanoes form when magma reaches the Earth's surface, causing eruptions of lava and ash. They occur at destructive (compressional) and constructive (tensional) plate boundaries. The immediate effects of volcanic eruptions can be devastating, but they may be beneficial in the long term.
The volcanoes form on the continental side of a subduction zone. The melting oceanic crust forms pools of molten rock in a magma chamber. The magma, molten rock, in the magma chamber is lighter than the volcano rocks that surround it.The magma works its way to the summit where it erupts as tephra or in thick lava flows. Lava eruptions on stratovolcanoes.he melting oceanic crust forms pools of molten rock in a magma chamber. The magma, molten rock, in the magma chamber is lighter than the volcano rocks that surround it. The magma works its way to the summit where it erupts as tephra or in thick lava flows. Lava eruptions on stratovolcanoes.