Can You Plant a Pine Cone and Grow a Tree?

How Pine Cones Mature and Release Seed

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Genetically Superior Ripe Pine Cones. Gerald Crowell, Virginia DOF

Many people imagine that pine cones--or the individual scales within the pine cone--are the tree's seeds, and by planting the pine cone you can grow a new pine tree. 

That's not the way it works, though. 

What, Exactly, Is a Pine Cone?

In the biology of pine trees,  the cone is actually not the seed at all, but a "fruit" structure that nurtures two pine seeds between each pointed or prickly scale of the cone.

 What we normally think of as a pine cone is actually the female reproductive structure of the tree. Pine trees also have male cones that produce the pollen, but these are generally much less conspicuous on the tree, and you may overlook them entirely. 

On most coniferous trees, the familiar woody cone is actually a very special container full of seeds that is designed to open when the green cones ripen to maturity. Each species of conifer sports a different type of pine cone, and they can range from very small round cones with brittle hard scales, to long narrow cones with thin, prickly scales, and everything in between. Examining the shape and size of its cone is one way to identify which species of conifer you are looking at. 

How Pine Seeds Ripen and Distribute

In pines, two seeds are wedged in each scale of the female cone, and they will drop from the mature cone when conditions are right and the cone and seeds are fully mature.

More seeds will drop from large pine cones than from small cones, and hundreds of seeds per cone are common, depending on the species.

Look closely at a conifer, and you will likely see a number of green cones on the tree that have not yet ripened. Depending on the tree species, these can take anywhere from one year to several years to ripen into the brown, dry cones that are more readily apparent on the tree or on the ground around the tree.

At the point where the cones become fully brown, they are fully ripened and the seeds have likely already been dispersed or are in the process of dispersing. "Spent" cones are those littering the ground around the tree. The cone itself is only the protective covering for the seeds inside, and on most trees there will be several seasons worth of cones developing on the tree, each at different stages of ripening. It is usually in the fall of the year when pine cones drop to the ground. The typically dry condition of late summer and fall is the trigger that causes most cones to ripen, open and distribute their seeds to the wind.

Most new pine trees begin when the tiny seeds are blown about by the wind once released from the cone, although some are begun when birds and squirrels feed on the seeds and distribute them. You can identify animal feeding by looking for the remnants of pine cones on the ground around the tree. 

The term serotiny refers to a plant in which the maturation and release of seeds are dependent on certain environmental conditions. A prime example is found in several species of pines that are serotinous, using fire as the trigger to release seeds. The jack pine (Pinus banksiana) , for example, will hold its pine cone seeds until the heat of forest fire causes the cones to release their seeds.

This is an interesting form of evolutionary protection, as it ensures the tree will reproduce itself after a disaster. A huge number of new trees sprang up in Yellowstone National Park after terrible forest fires in 1988, thanks to pine trees that were serotinous to fire. 

How to Propagate Pine Trees

So if you can't simply plant a pine cone to grow a new tree, how do you do it?

Even if you plant a cone with mature seeds just about to drop, you will have planted the seeds too deep. The moisture of the ground and the woody cone material trapping the seeds will prevent them from germinating. A pine seed actually needs only light contact with the soil to germinate.

If you're intent on germinating your own pine tree seeds, you will need to collect the very small seeds from the cone and prepare them for planting.

These seeds have little "seed wings" that help scatter them to the ground surrounding the parent tree. Nurseries collect the maturing green cones, dry these cones to open the scales and manually extract the seeds for growing seedlings. Preparing those seeds for planting is an involved skill but one that can be learned.