Why Do Pine Trees Have Cones?

Overview

Pine cones are more than a decorative holiday wreath or centerpiece insert. Cones are the essence of life for new forest growth. These protective seed pods are necessary to the production of future pine trees. The woody cones are food for birds and animals, which in turn help spread the fertile seeds throughout the forest.

Pollination and Fertilization

Male cones develop at the tips of the branches near the bottom of the tree. Each scale on the 1- to 2-cm cones produces pollen. Pollen grains that release from the male cone spread to the larger female cones, which grow nearer the top of the tree. Each scale of the female cone has two ovules. The female scales open to receive the pollen when it is released. Pollen sparks the slow-growing development of a pollination tube within the female cone. Male sperm that are released from within the pollination tube fertilize an ovule's eggs 15 months after pollination. The seeds develop inside the female cone as it grows to maturity.

Immature Cones

A pine cone takes up to three years to come to full maturity. The immature cone may be green or a light tan color. Cone size and colors vary according to the species of pine tree. The scales of the cone are thick and tight against the immature cone interior. The exterior immature scale or umbo of the cone may be armed with a rough spine.

Seeds

The third season of cone development brings the process to maturity. The fertilized ovule is maturing and developing embryo, food storage and a protective seed coat. At full maturity the female cone opens or ''blossoms'' fully to release the seeds. A thin, membranous layer of cone scale coats the seeds, giving them a set of wings that allow each tiny unit to lift and disperse on the wind.

Mature Cone

The mature cone has a stiff, woody texture. The cone scales may open when dry or stay sealed with resin that the particular species produce. The mature cone has a pleasant woody fragrance. The twig connection that holds the cone on the tree weakens as the cone matures. The cones begin to drop when movement from wind and feeding squirrels and birds dislodge them from a tree. Seeds that remain within the cone are borne to the ground. Feeding animals carry cones away to their nests, spreading more seeds as they travel.

Significance

The process of pollination, fertilization, seed growth and dispersal takes place within the pine cone. Cones that range from 2- to 20- inches or more in length hold the future of the forest within their protective scales.

Keywords: pine cones, tree pollination, pine tree seeds

About this Author

Suzie Faloon is a freelance writer who has written online content for Demand Studios and Associated Content. As a professional crafter and floral designer, Faloon owned a florist business for nearly 25 years. She completed the Institute of Children's Literature course in 1988.