Whenever it rains hard during the summer, pine cones seem to rain down, the cones knocked from branches in the upper canopy of tall white pines before the cones are fully mature. On non-rainy days, squirrels and insects nibble at them, causing more to rain down. Sometimes woodland trails and our road are littered with cones. We've had some good, good rains this summer and there are lots of squirrels, so consequently there are a lot of fallen cones.
White pine cones are interesting. They are rather like green frogs and bullfrogs in that they take two full years to mature. During the first spring female flowers (which become the cones) are pollinated by the male flowers (which wither and die after releasing their pollen into the wind). You will recall all the yellow pine pollen that floats in the air and in puddles after a good spring rain. So, after pollination the female flower forms a small "cone," about the size of your thumb by fall.
My friend Karen Bennett, who knows all things about trees, provided great info for this blog post, including the tip about thumb-sized female cones. The female cones remain about the same size through winter. When the second summer comes around, the female cones start to grow and expand. They reach maturity at five inches or more by fall. Everyone can recognize a mature female pine cone -- brown and woody (see photo below). Once mature they open fully and drop their seeds, if the rain and the squirrels and the insects haven't gotten them first.
In summer, before the cones have matured, you might see these on the ground, again felled by rain, squirrels, or insects.
Both cones in the above photo are female second year cones, not yet mature. When the cone first starts to expand in spring it is green, then changes to a purplish color, before becoming woody and brown in fall. Squirrels are after the 2 seeds tucked into each papery scale.
Some years are great seed years for white pine. This does not seem to be one of them, despite the cones strewn on the ground. You know a good crop year when you look into the top of a big white pine and see the upper branches laden with female cones.