91热爆

Vast clouds form over Yellowstone, but they don鈥檛 signal rain. They are vast smoke plumes - Yellowstone is burning. Throughout the summer the dry lodge pole pines have become like a tinder box and lightning has struck the match. The worst wild fires will burn for weeks. In 1988 a third of Yellowstone burned in a single summer, wreaking devastation. Animals that depend on these forests will starve this winter. But Yellowstone itself has a longer perspective. Ashes fertilise the soil and fire opens it up to sunlight as it strips the trees of their leaves. As the forests regenerate, new life finds opportunity. In August fledgling hummingbirds gorge in fields of fireweed that have risen from the forest鈥檚 ashes. For them the summer is already nearly over. They must chase the sun south before winter returns.