Part IV. The effects of the eruption of 1961 on the vegetation of Tristan da Cunha

Abstract Volcanic eruptions affect vegetation in various ways according to the nature and quantity of the material ejected. Lava, pyroclastics and gases all cause damage in different degrees, varying with the type of eruption. Lacroix (1908) recognized four types of volcanic activity, viz. Hawaiian, Strombolian, Vulcanian and Pelean. The Hawaiian type is characterized by the production of a great deal of lava but little pyroclastic material. At the other extreme, the Pelean type produces great explosions with copious pyroclastics but little lava. In Hawaii, the damage to the vegetation caused by eruptions is due largely to burial by the lava flows (MacCaughey 1917; Skottsberg 1941; Britten 1956). However, in volcanic areas such as the Lesser Antilles, Papua and the Philippines, where there have been paroxysmal eruptions, damage resulted principally from the force and heat of the blast and the great quantities of pyroclastics thrown out (Anderson & Flett 1902; Anderson 1908; Taylor 1958; Brown, Merrill & Yates 1917).