Wood ignites at temperatures in the hundreds of degrees. How are some wildfires supposedly started by sunlight without human action or lightning?

Question

Wood ignites at temperatures in the hundreds of degrees. How are some wildfires supposedly started by sunlight without human action or lightning?

In: 1508

Answer 1

Pitch pine in eastern Long Island NY exude a drop of sap that focuses the sun to ignite themselves. Fires have ignited on bright sunny days miles from nowhere.