We expect to see Oaks and Maples lose thier leaves at this time of year, but why are conifers stripping down too this year?
Welcome to Something Wild. I'm Iain MacLeod from the Audubon Society of New Hampshire.
This time of year is like a sea of leaves when you walk in the woods. But this year I noticed that I was kicking up more pine needles, in addition to maple and oak leaves.
Pine trees do lose their leaves, as do most other conifers such as spruce and hemlock. Every year these trees lose some of their needles; how long they stay depends on the tree. Hemlocks, for instance, retain their needles for only a couple of years, while the famous bristlecone pines of the West can have needles that are 30 years old.
But why these trees don't lose all their leaves is interesting. As you travel around the state, and the world, you'll see that conifer trees are often more dominant in areas where conditions are harsh - like in the North, for instance. The stunted Krumholtz pines on mountaintops are usually spruce trees, and conifers do well in areas that have nutrient-poor soils.
Why is this? Well, it takes a lot of nutrients to regrow your leaves every spring. It is much more efficient to hold onto them for multiple years. So where nutrients such as nitrogen are scarce, conifers have a "leaf up" on deciduous trees, if you will.
In times of stress, conifers can lose more than their usual number of needles, so this year, when we've had a bad drought, it is conceivable that there are more needles on the ground. Not to worry, though - it's just another survival mechanism from trees that live under some of the most difficult conditions on Earth.
If you have a natural history question that you'd like answered on Something Wild, e-mail us at somethingwild@nhpr.org.
Something Wild is a joint production of NH Audubon, NHPR and the Society for the Protection of NH Forests. For Something Wild, I'm Iain MacLeod.
