Vegetation in the Tundra: How do Plants Live in the Cold?
Today’s blog post is brought to you by Xander Kalna
Some of our students in the YCITYSCI Program asked about how plants survive in different climates. Today’s blog post is about the plants that grow in the tundra! Tundras are similar to deserts in that they receive very little rainfall during the year and most of the water is frozen year round. In fact, some tundras may actually be deserts!! Tundras are found in the extreme north (the Arctic Circle), Antarctica, and some very high mountain tops.
Just like in deserts, plants face a whole host of challenges to survive in the tundra. Plants must live with very little precipitation, freezing temperatures, high winds, frozen and poor soil, and very short growing seasons. There are several adaptations plants have found to survive despite these challenges.
While the stereotypical desert is hot, the tundra is cold! Ironically, in both environments, plants have devised a few similar traits such as hair! While cacti don’t really have hair, they have their spines and thorns which can help protect the plant from the sun and wind. In the tundra, many plants have hair on their stems and leaves for the same reason! The hair helps trap warmer, moist air that is given off by the plant and prevents the strong winds from taking it and replacing it with cold, dry air. Similarly to thorns and hair, tundra plants usually have small leaves with thick cuticles like desert plants do. This is since small leaves lose less water than big leaves and small leaves are quicker to grow and replace. Along with hair and small leaves, many plants of the tundra grow in small dense clumps. Just like penguins huddling together, the clumping of plants help them stay warmer together and protect each other from the wind.
In the tundra, the soil is often permanently frozen, this is called permafrost. Throughout the year, some portions may thaw like in the summer. Due to this, most tundra plants have very shallow root systems as they cannot grow through the frozen soil. Coinciding with the frozen soil, the growing season is usually only a month or two long as these environments are near the poles of the Earth. This means the winter months may have extremely short periods or no periods of sunshine at all! Meanwhile, the summer months may have entire 24-hour periods of sunlight! This is due to how the Earth is tilted, in the summer, the Arctic (Canada, Russia, Alaska) receives entire days of sun while in the winter, these areas receive very little or no sun at all. Due to this, nearly all the plants of the tundra are small and most trees that do grow are dwarf trees, only reaching a few feet tall. Since the growing season is so short, tundra plants have adapted to photosynthesizing with very little sun and in extremely cold temperatures. Once the growing season is upon them, these plants grow very quickly.
To take advantage of the growing season, many plants have dark leaves to better absorb the energy of the sun as well as cup shaped flowers. These flowers are cup shaped to better focus the warmth of the sun on them to aid their growth. Many flowers can actually rotate to always face the sun while it moves across the sky.
Feature image by dmitriy ostretsov from Unsplash.
Second photo: by Amanda Graham from Yukon White Light