Dendrovolcanology is the application to the study of effusive and explosive volcanic eruptions. The effects of the eruptions on plants may be destructive or favourable to growth (fig. 1) as in the eruption of Mount St Helen-Usa, 1982. In other cases the ashfall on treetops can induce growth reductions that last few years (fig. 2). In the case of dating of lava flows are examined the plants more or less damaged during their passage as in the case of the 2002 lava flow on the volcano Etna-Sicily, South Italy (fig. 3) and in the oldest lava flow of 1910 (fig. 4).