Love them or hate them; squirrels can be pests. But they also play an essential role in the ecosystem. These furry rodents bury and hide nuts in various places, only to forget about them, which helps trees and other plants grow. So how many trees are planted by squirrels, and why is this good for our environment?
Studies show that a single squirrel can bury as many as 10,000 nuts annually, but no one really knows how many trees they plant annually. That said, they play a massive role in the ecological role of the forest ecosystem through forest regeneration and seed dispersal. Squirrels are caching animals, meaning they bury acorns and other seeds in caches underground to save them for the winter months when food is scarce. Some squirrels will forget where they buried the nuts or die, giving the seeds a chance to grow into a new tree.
This means that they play a vital role in the growth of forests. In fact, without them, many of our forests would not exist. Maybe that’s stretching it too far, but tree regeneration is vital for the growth of new trees when others die off from sickness, fires, etc.
So why do squirrels bury nuts? What type of nuts do they bury, and how does it help our environment?
Well, let’s take a look at how these furry little creatures help our planet.
How Are Squirrels Responsible for Planting Thousands of Trees Worldwide?
Squirrels can be found everywhere from deserts, tropical rainforests, and in woods across America. There are over 200 species of squirrels throughout the world. The United States is home to five types, ground, fox, flying, gray, and red squirrels.
These rodents love nuts and trees. Unlike other animals, they don’t hibernate during the winter, so they are continually caching nuts to help them survive. Squirrels can bury and cache between 40 to 100 pounds of nuts yearly. This includes acorns, hickory nuts, hazelnuts, beechnuts, chestnuts, etc.
Once they find the perfect nut, they hide the nuts over a seven-acre area in preparation for winter. Caching happens year-round but is predominant in the autumn months.
All these nuts spread throughout the woods help new trees to sprout and grow.
Squirrels are critical to the regeneration of our forests, which helps to ensure a continuous supply of oxygen and fresh water. A scientific study has shown that the grey squirrel (Sciurus carolinensis) is the leader in seed dispersion.
These squirrels store 96.9% of the seeds and nuts, and 30% of the buried seeds are never recovered.
In addition, squirrels only bury the healthy goods seeds that have a chance of growing. They eat the damaged ones by doing a nut test.
When a squirrel sees a nut, it will do a quality control test to ensure it’s a worthy nut. The test consists of a quick sniff to see if it’s rotten and a close-up inspection. They are looking for cracks or holes. If they notice any, they won’t cache it because they know it will rot in the ground.
The last step is the shake test. They put the nut in its mouth and shake their head to see if there is a seed inside. The shake test also helps them determine the weight and quality of the seed inside.
Once they find the perfect nut, they look for a place to hide it.
How Many Seeds Do Each Squirrel Bury?
To better understand the importance of each squirrel, the table below will show you how much each type of squirrel buries and plays a part in tree regeneration.
Type of Squirrel percentage of seeds consumed, buried, and forgotten.
Red Squirrel 95% seeds buried
Grey Squirrel 96.9% seeds stored
Flying Squirrels: N/A (I couldn’t find the percentage online)
That said, the average squirrel buries 50-100 nuts daily, which amounts to many seeds and nuts planted worldwide without the assistance of humans.
What’s also interesting is that each type of squirrel has a different way of storing its food. For example, the red squirrels store large piles of nuts called “middens” at the base of trees. The red squirrel is not a scatter hoarder like fox and gray squirrels.
Flying squirrels cache seeds and nuts in tree cavities, crotches of limbs, their nests, and tree cracks. They even bury seeds in the ground. These squirrels have a preference for oak, acorns, and hickory nuts.
The Importance of Tree Regeneration
Trees are crucial to our environment and help to keep our planet healthy. They produce oxygen, which we need to breathe, and they help to filter the air we breathe. Trees also help to regulate the climate by providing shade and cooling the air in hot weather. In addition, trees help to prevent soil erosion and provide homes for many animals.
Squirrels, birds, mice, and other animals play a huge part in tree regeneration. Each year, these animals spread millions of seeds that help to grow new trees. That said, squirrels are one of the most important animals that play a considerable role in planting new trees.
Why Do Squirrels Bury Nuts and Seeds?
Many people believe that squirrels store their nuts in preparation for the winter months when food is scarce. While that may be true, that’s not the only reason. A 2017 study from the University of California Berkeley shows that tree squirrels are scatter-hoarding animals.
It’s in their DNA to cache nuts, so even if you have a pet squirrel, you will see them trying to cache a nut. For example, here’s a pet squirrel that tries hiding a nut in a Bernese Mountain Dog’s fur.
These animals use a mnemonics technique called “spatial chunking” to sort and bury nuts based on size, nutritional value, taste, and type. This technique helps them remember where they buried the nut, making it easier to find.
Squirrels Are Manipulated By The Trees
We all know that squirrels love nuts, that’s why you’ll find them in your backyard trees. However, some trees such as oak trees manipulate them by producing more nuts to help encourage the spread of their seeds.
How Do Squirrels Remember Where They Buried Their Nuts?
Even though squirrels have a good sense of smell like dogs, they don’t rely on their senses. Scatter hoarding animals can remember where they cached food.
The chunking method used to bury the seed makes it easier for them to recall caching locations.
A squirrel’s cache consists of food foraged from a single location. For example, if they cached acorns in one area, the cache consists of acorns only.
The study also showed that compared to other nuts, a squirrel’s caching behavior changes when exposed to almonds, walnuts, and hazelnuts.
How Deep Do Squirrels Bury Nuts?
Squirrels bury their nuts one inch (2.5 centimeters) under the soil. This ensures that the nut is safe from both predators and the elements. What they don’t realize is they may be accidentally planting a tree.
Although, up to 25% of their buried nuts are lost to thieves. They use false stashes or hide their nuts in hard-to-find places.
Once planted in the soil, the seed needs water, the right temperature, and light to start growing. When the squirrel plants the seed in the soil, the embryo or seed gets the signal to start growing, also known as the germination process.
This lengthy process can take weeks, months, or even years.
The time it takes for a tree to germinate and grow depends on the type of tree. For example, an oak tree can take up to 4-6 weeks to germinate, whereas a maple tree can take up to 90-120 days.
Squirrels are amazing animals that significantly affect forest regeneration and seed dispersal, which benefits us in many ways. While all squirrel species play a part in the process, the grey squirrel is the leader in the ecological role in the forest ecosystem.
These animals are essential for new tree growth and maintaining a healthy forest. If you have ever wondered how many trees are planted by squirrels, the answer is a lot!
With the help of these furry little animals, we can ensure that our forests remain healthy and continue to provide us with the many benefits trees offer.
So the next time you see a squirrel running around with a nut, take a moment to appreciate all the hard work they do for our environment.