I know I have said this before, but I will say it again – I love running around in the snow in the Rocky Mountains. It is just so much fun to jump up and down and land in the soft, fluffy white stuff.
Other than all of the snow blanketing the ground, the snow also blankets the bare branches on trees and drapes over the needles on evergreen trees after a new snow. The last time I went for a walk in the Rocky Mountains I began to wonder why all the trees higher up on the mountain were the conifer trees and not the broadleaf trees that lose their leaves in winter.
Well, I put my nose to work and did some research to find out the answer to that question.
Once again, as seems to be the answer to most questions about why the natural world is the way it is, the answer is survival. Conifer trees, such as pine trees and other common trees of the Rockies, are adapted to survive higher up on mountains where broadleaf or deciduous trees can’t live. You can learn all about the common trees of the Rockies and more with Jake’s Nature Guide: Rocky Mountains.
What are the challenges to surviving at higher elevations?
The higher up in elevation you go on a mountain the harsher the conditions are for survival. The areas higher up on mountains are windier, colder, and receive more snow than places lower on the mountains or in valleys. The weather also stays colder longer higher up in the mountains, which means there is a shorter growing season – the time when plants and trees can grow.
Conifer trees have the following advantages that help them survive in higher elevations on mountains:
NEEDLES NOT LEAVES
Conifer trees do not have leaves, but instead have needles. Similar to how you can tell what kind of tree it is by looking at the leaves, you can help identify an evergreen tree by the needles. Different kinds of trees have different lengths and even shapes of needles.
One reason needles help trees survive at higher elevations is because they keep the tree from losing too much water through its leaves (Needles and leaves lose water from their leaves through tiny openings that open for photosynthesis to occur). Needles are smaller than broad leaves so there is less surface area from which to lose water. Needles also have a waxy covering that keeps in water.
In the wintertime there may be a lot of snow around, but there is actually not a lot of water around in a liquid form, which is what trees need to survive. So, if a tree loses too much water it would die.
A second advantage of having needles at higher elevation is that trees do not have to grow new leaves in spring. Growing new leaves every year takes a lot of energy for a tree. In the mountains there is a much shorter growing season and all plants and trees need to take complete advantage of that small amount of time in order to survive.
One final advantage of needles is that they allow the tree to photosynthesize all year long. This means that even in the middle of winter on a sunny day, and if there is enough water, they are able to create their own energy. This gives them an extra advantage that helps them survive in the harsh mountain environment.
Have you ever noticed that Christmas Trees and all conifer trees have a nice conical shape? That shape is important because it keeps them from falling over in the winter from too much snow collecting on them.
Snow accumulates on branches and leaves or needles when it is snowing a lot. The conical shape of conifers prevents as much accumulation as there would be on a wider shaped tree. The conical shape of the tree also helps to get the snow to fall off the tree quickly.
Winter can damage trees with too much snow accumulation on a tree causing it to break off and fall down. In addition to the conical shape of conifers, some tree species, such as firs and spruces have another important feature that helps them survive – they are quite flexible. This allows them to bend as lots of snow accumulates and piles up on them. This flexibility keeps them from breaking under heavy loads of snow and then their conical shape helps them shed the snow and they then return to their normal upright position.
You can learn more about the different kinds of conifer trees in the Rocky Mountains in Jake’s Nature Guide: Rocky Mountains.