The treeless landscape of the North American Great Plains prompted European explorers to call it the “Great American Desert”.
The Great Plains of North America are a vast, treeless expanse of grasslands that cover a significant portion of the continent. While the lack of trees may seem puzzling, there are several factors that contribute to the treeless landscape of the Great Plains.
Firstly, the Great Plains are characterized by a semi-arid to arid climate, with low annual precipitation and high evaporation rates. This means that the region experiences prolonged periods of drought, which makes it difficult for trees to establish and survive.
Secondly, the soil in the Great Plains is often shallow and nutrient-poor, which further limits the growth of trees. The grasses that dominate the landscape have adapted to these conditions and are better suited to thrive in this environment.
Finally, wildfires have historically played an important role in shaping the landscape of the Great Plains. Grasses are better adapted to withstand fires than trees, and the frequent burning of the grasslands has prevented the establishment of forests.
Which is the Great Plains climate?
The Great Plains are characterized by a semi-arid to arid climate due to several geographic and meteorological factors.
Firstly, the Great Plains are located in the interior of the North American continent, far from the moderating influence of the oceans. As a result, the region experiences a continental climate, with large temperature variations between summer and winter and limited moisture from the oceans.
Secondly, the Great Plains are located in the rain shadow of the Rocky Mountains, which causes a significant reduction in precipitation. Moist air from the Pacific Ocean is forced to rise over the Rockies, where it cools and releases precipitation on the western slopes. By the time the air reaches the Great Plains on the eastern side of the mountains, it is drier and has less moisture to produce precipitation.
Finally, the North American Monsoon, which brings moisture to much of the southwestern United States, does not extend far enough north to affect the Great Plains. The region is therefore largely dependent on precipitation from frontal systems and thunderstorms, which are often sporadic and unreliable.
The rain shadow of the Rocky Mountains and Great Plains
The rain shadow of the Rocky Mountains is a meteorological phenomenon that occurs when moist air from the Pacific Ocean is forced to rise over the mountains, which causes it to cool and release precipitation on the western side of the range. As the air descends on the eastern side of the mountains, it warms and dries out, which leads to a reduction in precipitation and a drier climate in the region known as the rain shadow.
The Great Plains are located east of the Rocky Mountains and are therefore in the rain shadow of the range. This means that much of the moisture in the air has already been released as precipitation on the western side of the mountains, and by the time the air reaches the Great Plains, it is relatively dry.
The Rocky Mountains act as a barrier to the prevailing westerly winds that carry moist air from the Pacific Ocean. As the air is forced to rise over the mountains, it cools and releases moisture, which leads to higher precipitation levels on the western side of the range. The mountains also provide a physical barrier to storms that might bring precipitation to the Great Plains, which contributes to the arid climate of the region.
Overall, the rain shadow of the Rocky Mountains is a significant factor in the semi-arid to arid climate of the Great Plains. The lack of moisture from the Pacific Ocean, combined with the reduced precipitation caused by the rain shadow effect, makes it difficult for trees and other vegetation to grow and thrive in the region.
Why don’t trees grow in the Great Plains of North America?
Why? There are several reasons. The Great Plains region of lower Canada and the midwestern U.S. doesn’t have enough of a natural supply of water to support trees easily – except near streams and rivers. Stream and riverbeds in the Great Plains are occasionally lush with cottonwoods and willows . . .
But for the most part wild grasses dominate the Great Plains. Grasses thrive on less water – and they survive wildfires better than trees. Grasses readily come back after a fire because they sprout from roots that reach much deeper beneath the soil than grass blades do above the soil. On the other hand, most trees grow from points that are close to the bark. Once these “growing points” are damaged, the tree has little chance of surviving.
In past centuries, the grazing of bison also limited the growth of trees in the North American Great Plain. But today – with the removal or control of large grazing animals and widespread fire suppression – trees such as junipers are becoming a more common part of the Great Plains landscape.
Not enough of a natural supply of water to support trees
The Great Plains region of lower Canada and the midwestern U.S. is characterized by a semi-arid to arid climate, with low annual precipitation and high evaporation rates. This means that the region experiences prolonged periods of drought, which makes it difficult for trees to establish and survive. However, trees can grow and thrive in areas near streams and rivers where there is a more abundant supply of water.
The reason for this is that trees require a consistent supply of water to survive, and streams and rivers provide a reliable source of water that is not dependent on precipitation. The water in streams and rivers is also often deeper and more nutrient-rich than the shallow, nutrient-poor soil found in much of the Great Plains, which can support the growth of trees.
Additionally, trees near streams and rivers can benefit from the cooler temperatures that result from the presence of water. The water helps to regulate temperature extremes and provides a more favorable microclimate for tree growth.
The amount of water that the Great Plains receive in one year
The amount of water that the Great Plains receive in one year can vary significantly depending on the specific location within the region and the prevailing weather patterns during that year. However, on average, the Great Plains receive between 10 and 20 inches (25-50 cm) of precipitation per year.
It’s worth noting that the Great Plains are a vast region that covers multiple states and provinces, and there can be significant variations in precipitation patterns within the region. For example, areas closer to the Rocky Mountains may receive more precipitation due to the effects of orographic lifting, while areas farther east may receive less precipitation due to the rain shadow effect.
Additionally, weather patterns such as droughts or El Niño/La Niña events can have a significant impact on precipitation levels in the Great Plains. For instance, the region experienced a severe drought in the 1930s known as the Dust Bowl, which had devastating effects on agriculture and the economy.
Trees plantation experiments in the Great Plains
There have been several tree plantation experiments in the Great Plains over the years, with varying degrees of success. The goal of these experiments is to determine which tree species are best suited for the region’s climate and soil conditions and to develop methods for establishing and maintaining tree plantations in the Great Plains.
One notable example is the Shelterbelt Project, which was initiated by the U.S. government in the 1930s in response to the Dust Bowl. The project involved planting a belt of trees across the Great Plains to provide a windbreak and prevent soil erosion. The trees planted in the Shelterbelt were primarily native species such as cottonwood, red cedar, and green ash, although some non-native species such as Siberian elm and Austrian pine were also used. While the Shelterbelt Project had mixed success, it did help to demonstrate the feasibility of establishing tree plantations in the Great Plains.
More recently, there have been efforts to establish agroforestry systems in the Great Plains, which involve integrating trees into agricultural landscapes. These systems can provide benefits such as improved soil health, increased biodiversity, and improved water quality, while also providing a source of timber and other products.
Conclusions about trees in Great Plains of North America
While it is true that trees do not naturally grow in many parts of the Great Plains of North America due to the region’s semi-arid to arid climate, there is ongoing research and experimentation aimed at developing methods for establishing and maintaining tree plantations in the region. Some of the reasons why trees are not abundant in the Great Plains include:
- Low precipitation levels: The Great Plains receive relatively low levels of precipitation, which can make it difficult for trees to establish and grow. However, there are certain tree species that are better adapted to the region’s dry conditions, such as cottonwood and bur oak.
- High evaporation rates: The region also experiences high evaporation rates due to its hot and dry climate, which can further limit the amount of water available to trees.
- Soil conditions: The soils in many parts of the Great Plains are shallow and nutrient-poor, which can make it difficult for trees to establish and thrive.
Despite these challenges, there is ongoing research and experimentation aimed at developing sustainable and productive tree-based systems for the Great Plains. For example, the Shelterbelt Project in the 1930s demonstrated the feasibility of establishing tree plantations in the region, while more recent efforts have focused on integrating trees into agricultural landscapes through agroforestry systems.
Furthermore, establishing and maintaining tree plantations in the Great Plains can provide numerous benefits, including improving soil health, enhancing biodiversity, and providing a source of timber and other products. As such, while trees may not be abundant in the Great Plains naturally, there is potential for developing productive and sustainable tree-based systems in the region with the right management practices and species selection.