Douglas firs are relatively hardy evergreen trees. What makes them that way? How has the Douglas fir adapted to its environment? And what sort of environment does it live in in the first place? Keep reading to find out more!
What You'll Learn Today
What Environment Does the Douglas Fir Live In?
Douglas firs live in various environments. This evergreen species is found primarily in western parts of North America, where it has learned to adapt to various habitats.
There are six subspecies of Douglas fir, but those found in North America can be grouped into two broad categories: coastal and interior Douglas firs.
Let’s take a closer look at each and discuss the environments they live in.
Coastal Douglas Firs
Coastal Douglas firs get larger and live longer than interior Douglas firs. This is largely because of the coastal habitats they grow up in.
Coastal Douglas firs are found along the West Coast, particularly in the Pacific northwest region of the U.S. and western areas of Canada.
These trees tend to live at relatively lower elevations, from sea level to a couple thousand feet above sea level. The coastal environment provides for mild winters and wet summers, so the trees growing in this region are rarely exposed to extreme weather conditions.
These trees are primarily found in coastal forests, temperate rainforests, and mixed forests. They receive plenty of rain and snow each year, which is ideal for them.
Interior Douglas Firs
Interior Douglas firs have shorter lifespans and don’t grow as large as coastal Douglas firs. This is due at least in part to the fact that they live in more extreme environments.
These trees can be found in parts of Mexico, northward through the Rocky Mountains, into interior portions of western Canada, and as far north as southern Alaska. As you might imagine, they live in a variety of environments in these regions.
They tend to live at higher elevations, around 5,000 feet or more above sea level. In the southern part of their range, they experience hotter summers; further north, they must survive bitter cold winters.
These trees are found in evergreen taiga forests and mountain habitats.
How Has the Douglas Fir Adapted to its Environment?
Regardless of whether they are coastal or interior Douglas firs, these trees have had to adapt to their environment over time. Even those in seemingly ideal coastal climates face yearly threats of forest fires and high winds.
With this in mind, let’s take a look at some of the adaptations of Douglas fir trees.
Douglas firs have developed thick, fire-resistant bark which strengthens and grows thicker as they age. This bark plays a couple of different roles in protecting the trees.
First off, the bark provides a thick “armor” against fire, allowing mature trees to survive small to moderate forest fires. Though large fires or prolonged fire exposure will eventually win out, this layer of bark allows the tree to survive conditions that would kill other trees far more quickly.
What’s more, this layer of bark can have the opposite effect.
The thick bark can also act as a coat to protect the tree from cold temperatures and harsh weather conditions. This is especially helpful for those found at higher elevations and in more northern regions, where the trees are more likely to be subjected to harsh winters.
The roots of Douglas fir trees run deep, providing extra strength in the form of a firm foundation. But, in addition to their depth, it’s also the style of the root system that lends this strength.
Douglas firs have what is known as an adventitious root system. This means that all of the tree’s roots grow directly from the bottom of the trunk instead of branching off from a few main roots.
In other words, there are more large roots growing from the bottom of each Douglas fir tree, providing a greater hold in the ground and a more solid foundation than many other types of trees have.
These strong, adventitious roots allow each Douglas fir to stand tall against high winds and heavy snowfall.
Douglas firs have a slight waxy coating over each of their needles. While this may seem like a small detail, it is actually a crucial adaptation that helps them survive harsh taiga conditions.
For one thing, the wax helps the needles to retain water, which can be extremely important in the dry air of winter.
What’s more, the wax adds a protective barrier against freezing temperatures. By both insulating the needles and holding in their moisture content, it makes the tree more resistant to bitterly cold temperatures.
Douglas fir trees have a fairly rapid growth rate. What does this have to do with adapting to their environment?
Young trees are naturally more susceptible to environmental threats such as harsh weather, pests, fire, and wind. The sooner a tree can grow large and begin reproducing, the better its chances of surviving long enough to continue the species.
Douglas firs add an average of 24 inches of growth each year. This allows them to reach healthy sizes in a few short years, as well as continue growing and becoming more resilient with each passing season.
The branches of Douglas fir trees do not break easily. They are flexible, which allows them to bend and give beneath heavy snow.
In turn, this limits damage which could ultimately weaken the tree.
Check out this video to learn more about Douglas fir trees and the environments in which they are found:
Douglas firs can be found in a variety of environments, from mild coastal regions to temperate rainforests to harsh taiga landscapes. They have developed many adaptations to help them cope with the challenges they face in these diverse environments.