The Polly Hill Arboretum in Martha’s Vineyard currently hosts a traveling exhibit, Vanishing Acts: Trees Under Threat.  Fifteen species of trees highlight the various sources of threat and possible consequences of species loss for both humans and the ecosystems the trees inhabit.  Katherine Scott of the Vineyard Gazette says “Most threats are related, either directly or indirectly, to human activities: deforestation for timber, clearing for agriculture, climate change (affecting vulnerability to pests,) invasive plants competing with native species and exploitation of the tree as a resource.  The trees in the exhibit represent six of the seven continents.”  For more information call 508-693-9426. For the complete article visit http://vineyardgazette.com/news/2015/03/18/exhibit-highlighting-threatened-trees-comes-polly-hill?k=vg554251c965519&r=1.