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.
Volcanoes result when magma rises to the Earth's surface. One process that results in magma being formed, is the melting of tectonic plates being subducted. Therefore, most volcanoes are likely to occur along convergent or divergent tectonic plate boundaries.here are three types of lithospheric plate boundaries: convergent plate boundary, divergent plate boundary and transform plate boundary. Earthquakes and volcanoes most frequently occur along tectonic plate boundaries.