Pine cones reproduce by releasing seeds, either with wing-like structures that help them be dispersed by the wind or without wings to be dispersed by animals. The cones themselves are made up of woody scales that protect the seeds until they are ready and the conditions are right.
What are commonly called pine cones are the female cones of conifers, but they grow male cones as well. Sometimes a single tree grows both types of cones, while in other species, each individual only grows one type. Male cones are relatively small and are soon dropped after they release their pollen into the wind. Female cones are much more conspicuous and are retained for longer periods.
During seed development, female cones are kept tightly closed, usually sealed by a resin. Once the seeds are ready, most conifers open up their cones and release them. Some conifers, however, require specific conditions to open their cones and release seeds. Pitch pines, for instance, require high heat from a forest fire to make their cones open up. Under these conditions, most twigs and leaf debris burns, and their seeds have the best chance of reaching open ground so their roots can emerge and begin growth.