dieback

dieback
 n.— «The team believes that the process, known as dieback, will begin when average global temperatures reach around 15C. Weather system changes will mean less rainfall on the jungle which will result in saplings failing to reach maturity while older trees die and wither away. Once the process begins it will feed on itself as less tree cover will mean less water evaporation to create more rain. Eventually it could have the effect of turning more than a million square miles of the jungle in Brazil into savannah.» —“Amazon rainforest at risk of ecological ‘catastrophe’” by Richard Alleyne Telegraph (United Kingdom) Mar. 12, 2009. (source: Double-Tongued Dictionary)