Bristlecone pine cones. View of male and female cones on a bristlecone pine tree Pinus aristata. The cones are the reproductive structures of the tree. The male cone (red, at lower right) produces large quantities of pollen in order to fertilize the ovules contained in the much larger female cone (dark brown). The female cone drips with the rich sap that enables some of these trees to live almost 5000 years. Studies of wood from these trees has provided much data on ancient climates. For example, it was discovered that climates more than 3600 years ago had a different carbon dioxide content, leading to a revision of the ages derived from carbon-14 dating.