Richard Preston said this quote

Doctors generally consider smallpox to be the worst human disease. It is thought to have killed more people than any other infectious pathogen, including the Black Death of the Middle Ages. Epidemiologists think that smallpox killed roughly one billion people during its last hundred years of activity onearth.

~ Richard Preston

In a sense, the Earth is mounting an immune response against the human species. It is beginning to react to the human parasite, the flooding infection of people, the dead spots of the concrete all over the planet, the cancerous rot-outs in Europe, Japan and the United States, thick with replicating primates, the colonies enlarging and spreading and threatening to shock the biosphere with mass extinctions. Perhaps the biosphere does not 'like' the idea of five billion humans.

~ Richard Preston

The coast redwood is the tallest species of tree on earth. The tallest redwoods today are between 350 and close to 380 feet in height--thirty-five to thirty-eight stories tall. The crown of a tree is its radiant array of limbs and branches, covered with leaves. The crowns of the tallest redwoods can sometimes look like the plume of exhaust from a rocket taking off.

~ Richard Preston

... tree has had a stroke, and its top dies. A redwood can deal with a stroke. It simply grows a new top in a few centuries.

~ Richard Preston