How Pine Cones Predict Rain

If you’re not so happy with the accuracy of your local weather forecast, here’s  something new to try when you’re wondering if it’s going to rain: check out some pine cones! They close in response to moisture in the air. They do this for the same reason they do everything else, to disperse their seeds as widely and effectively as possible. Dry conditions are more conducive to a fast and far-reaching dispersal; dampness reduces the effectiveness.

Pine cone scales have several layers. If water drops make contact with the upper layer when the cone is open, the water slides into the inner layer and causes it to expand. Once the scales begin to bend upward, they eventually curl shut. Then when the air becomes drier and the water inside the cone evaporates, the scales open up again. Pine cone seeds are designed to travel on the wind and can reach a distance of several hundred feet from their parent tree.

Here are some more fun facts about pine cones:

• A pine cone can stay on a tree up to 30 years before falling off.

• Depending on the species, each cone contains dozens to over 100 seeds. with two winged seeds at the base of each scale.

• Cones of the sugar pine, the largest species, can be up to 24” long.