Ripples 12/28/16

photo of pine conesPinecones are used to make wreaths, ornaments and other crafty projects. They are also be used as a bird feeder and even a firestarter. These cones are more than just a festive holiday decoration; they are part of an ancient form of reproduction for some of the largest and oldest organisms on the planet.

Cones are the reproductive structures of gymnosperms, the science term used for the group of plants that reproduce without flowers or fruit. Gymnosperm means “naked seeds” and refers to the unenclosed seeds. There are more than 1,000 gymnosperms in the world and this group includes spruces, pines, ginkgos and other conifers (cone bearing trees). Plants that produce flowers, have seeds that are contained in an ovary or fruit. These plants are called angiosperms and there are more than 300,000 in the world. Most angiosperms rely on help from pollinators such as bees, flies, butterflies and other animals to make seeds.

Most cone producing plants have male and female cones on the same tree. The female cones are what one pictures as a typical cone. They are woody and scaly and hold the seeds that will later form. The male cones appear for a short time as smaller, almost spongy looking cones and contain pollen. The scales on the female cones are tightly closed, except early in development. During this time, the scales open slightly to allow pollen to enter. The wind carries the pollen away from the male cones, which fall off shortly after the pollen is gone. After pollen enters, the scales of the female cone close to allow the seeds time to develop. For most species, seeds mature in about 6-8 months. However it can take 12 months for some cedars and 18-24 months for certain of species of pine. Once the seed is fully developed, the scales of the female cones flex open, allowing the winged seeds to escape and be carried by the wind. Some conifers require birds to break the cones open in order for the seeds to be released. For others, such as cedars and firs, the cones actually disintegrate and the seed scales fall off. Some trees, such as jack pines, require fire for seed dispersal. The heat of the fire opens the scales of the cone, releasing the seeds onto the ground that the fire just cleared of existing vegetation. The fire prepares the soil, reduces competition from other seeds and releases the jack pine seed.

It’s amazing to think the world’s largest living tree (by volume) started its life as a small seed from a cone. This tree is named “General Sherman” and is a whopping 275 feet tall and has a diameter of more than 36 feet at its base. The famous tree is located in Sequoia National Park in California and is believed to be about 2,500 years old! Cones may be a primitive and old method of reproduction, but they are highly successful.

In our area, there are many cone-bearing trees, including eastern hemlock, white cedar, balsam fir, and a number of native and non-native spruces and pines.  Because their cones can take a long time to mature, they differ in abundance from year to year.  They provide important food sources for wildlife, in addition to the interest and materials they provide for us.


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