Pine
At maturity, the cones usually open to release the seeds, but in some of the bird-dispersed species (e.g. whitebark pine), the seeds are only released by the bird breaking the cones open. In others, the seeds are stored in closed ("serotinous") cones for many years until a forest fire triggers the cones to open, releasing the seeds. The resin on the cones holds the scales closed until it melts in the fire.