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One of the simplest examples of how plants adapt to ensure that their species survives is found in pine cones.
Evergreen trees that produce cones are called conifers. There are more than 600 species of conifers — which include pines, firs and spruce — each with its own type and size of cones.
Species survive by reproducing. Conifers reproduce as their seeds spread, usually by wind.
According to the American Conifer Society, pines represent the largest group of conifers, so let's take a closer look at pine cones, which serve as seed protectors.
You might wonder why pine trees' seeds need protecting and how the cone helps.
Pine seeds are very small and attached to the end of wing-shaped membranes. The pine cone's protection mechanism is triggered by temperature and water.
After the seeds are pollinated in the spring, the woodlike brown scales that make up the pine cone's exterior close, curving upward and inward to make a tight seal around their seeds — often so tight that squirrels and birds have trouble reaching the seeds to eat them. This protects the seeds as they mature, which could take several years.
The scales open when conditions are just right — warm and dry so the seeds' winglike attachments can help them disperse in the wind. (Heavy, wet pine seeds won't travel far from their parent tree, so the evergreen needles above could block the light and water needed for them to grow.)
Such a clever adaptation!
You can watch the pine cone protection cycle happen in your own kitchen. Late fall is a good time to take a walk where there are pine trees and look for cones on the ground. (Don't go on private property without the owner's permission.) Select two that are about the same size.
Are they open or closed?
If closed, that means they were in wet conditions, so pat them with a towel and put them in a dry, warm place for a few days. Or, for quicker results — with an adult's help — put them on an ovenproof pan lined with aluminum foil, preheat the oven to 200 degrees, then place the pan in the oven for about 45 minutes. Check them periodically to see if the scales have opened. When they have, remove the pan from the oven and let the cones cool. Look between the scales for any seeds that might still be there. Tapping the cones firmly on a counter may help release any seeds. Study them.
Next, take one of the open cones and measure the height and circumference (around the widest part of the cone), then put that cone in a bowl of ice water. Write down what time it is. Soon you should see the scales closing. Once they are completely closed, make a note of how long that process took, then compare the sizes of the open and closed cones. How do they differ?
For fun, place another open pine cone in warm water and compare closing times with the cold-water cone.
The hard seed-producing cones you most often see are female. There are two seeds attached to each scale on those pine cones.
Male cones are smaller and yellowish, with long clusters of pollen needed to fertilize the seeds.
Pine cones can live in a tree for 10 years without falling, so each tree can have cones of different ages in different stages of development.
Easy pine cone craft
Owls love to nest in conifers such as juniper, pine and spruce trees. After experimenting with your pine cones, make some cute owls.
Materials: Several open pine cones, cotton balls, felt or construction paper, scissors, glue and large googly eyes.
Steps: Set a pine cone upright. Push cotton balls between the scales. Cut a face, beak, two wings and two feet from felt or construction paper and glue each in place. Glue on large googly eyes. Give your owl a name!