9 Amazing Differences Between Eucalyptus And Gum Trees

Canopy of native eucalyptus / gum tree

Some gum trees are eucalyptus trees, and some eucalyptus trees are gum trees, but not all gum trees are eucalyptus trees. Hah! Confused yet? Both eucalyptus and most gum trees are native to Australia, but nowadays they are also grown in the U.S. because of their valuable properties for fuel, pulp, paper, and oils. So, what’s the difference between the two?

Eucalyptus gum trees and non-eucalyptus gum trees can be distinguished apart based on their leaf shape, bark, growth cycle, native habitat, and height. The main difference between eucalyptus and gum trees is that eucalyptus is a genus while gum trees are species.

Read on to explore all the differences between eucalyptus trees and gum trees. We’ll go over differences, similarities, and also go over why they’re called gum trees (hint: it has to do with chewing gum!)

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Are Eucalyptus And Gum Trees The Same?

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Before we get started, we should probably establish if eucalyptus and gum trees are, in fact, different.

Eucalyptus is a broad umbrella that encompasses most of the gum trees out there. blue gum, manna gum, rainbow gum, red cap gum, and silver dollar gum are all part of the Eucalyptus group (genus). 

However, some trees fall outside that umbrella. black gum, sweetgum, and water gum are not eucalyptus trees. Instead, they are each in their category. 

Eucalyptus trees are a part of the myrtle family, which are evergreen trees. Water gum is also part of the myrtle family, but black gum and sweetgum are not. Black gum and sweetgum are both deciduous trees, meaning they lose their leaves in the winter.

So, what exactly does all this mean? It means that most gum trees are eucalyptus trees, but a few gum trees are not eucalyptus trees. 

For example, when talking about blue gum trees, yes, they are eucalyptus trees. But when talking about sweetgum trees, no, they are not eucalyptus trees.

9 Differences Between Eucalyptus And Gum Trees

For our purposes here, when we talk about eucalyptus trees, we’re referring to the most common ones like blue gum, rose gum, and red gum. When we refer to gum trees, we’re going to be talking about the non-eucalyptus gum trees like sweetgum and black gum.

How can you tell the difference between a eucalyptus tree and a gum tree? There are a few obvious differences, while some are more subtle. Let’s check it out!

If you’re interested learning more, take a look our piece on the different things gum trees are used for here.

Differences In Eucalyptus And Gum Tree Leaves

The leaves of an evergreen tree are easy to identify all year round. However, if you’re looking for sweetgum leaves, be sure to check before winter hits as this tree is deciduous and will lose them in the fall!

Sweetgum leaves have five deeply-lobed points that form a star shape, according to the Missouri Department of Conservation. The tips are pointed, with small serrations around the outside.

Eucalyptus trees like the blue gum do not have lobes. The leaves are rather oblong-shaped like a canoe and are tinged slightly blue. Redgum trees have leaves that are shaped more like a spear tip, are longer than a blue gum tree, and the leaves are simple green instead of tinged with blue.

Both water gum and black gum (non-eucalyptus) have oblong-shaped leaves as well. While a water gum’s leaves will remain green all year, the black gum is deciduous and will change to a brilliant red in the fall.

Bark Differences Between Gum And Eucalyptus Trees

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According to the University of Tasmania, Eucalyptus tree forests show a great tendency to start fires.

All in all, eucalyptus trees tend to be a pretty significant forest fire hazard as they’re quite dry. Their bark often peels off and litters the forest floors, or else hangs in strips. When caught, these strips readily transfer the fire to the crown of the trees where the highly volatile oil on the leaves, then catches fire.

The sweetgum tree has light gray bark with vertical and rounded ridges along the trunk. This is very distinctive from a eucalyptus tree, which has a smoother appearance and a light brown/tan color. Additionally, the bark of the eucalyptus tree often appears as if it’s peeling away from the trunk.

Differences In Height At Maturity Between Gum And Eucalyptus

Both eucalyptus trees and gum trees are fast growers. It is one of the main reasons why they are grown in North America despite being native to Australia. The fast growth rate and hardwood nature of the trees are great for manufacturing furniture, cabinets, and other timber products in a somewhat sustainable way.

When left to grow to their heart’s content, sweetgum and water gum trees will reach a height of up to 130 feet. Black gum trees are a little smaller, reaching a full height of only 30-50 feet, according to the University of Kentucky.

Eucalyptus gum trees are, in general, taller than non-eucalyptus gum trees. The blue gum, for example, can reach heights of up to 260 feet! That’s a big tree! Interestingly, up to 70% of a blue gum’s growth occurs in the first 10 years, according to the USDA Fire Effects Information System.

Native Range Of Eucalyptus And Gum Trees

We mentioned earlier that most eucalyptus and gum trees are native to Australia, but let’s dive down into the specifics.

Eucalyptus blue gum trees feel at home in Tasmania and southeast portions of Australia. Since the mid-1800’s they’ve also graced the U.S. in California and Hawaii, where they’ve since been able to thrive naturally. You can also find them in Arizona, but only as ornamental trees or windbreaks.

Sweetgum trees are native to the United States. They’re found mainly in the southeast from east Texas over to central Florida. They’re also found as far north as Connecticut and the southern regions of Illinois and Arkansas. Black gums are also native to the U.S.

The major difference here is that eucalyptus gum trees are native to Australia and its surrounding islands. Non-eucalyptus gum trees like sweetgums and black gums are native to the United States. 

Growth Cycle Of Eucalyptus And Gum Trees

Trees spend a whole lot of their time growing, gathering resources, and growing some more. They also spend quite a bit of time trying to conserve as much energy as possible so they can continue to grow and succeed.

Leaves help trees grow by doing their whole photosynthesis thing, but when fall and winter approach, the days grow shorter, and the photosynthesis party slows down.

It’s for this reason that deciduous trees like the sweetgum and black gum tree drop their leaves in the fall. It prevents moisture loss while the tree goes into a semi-dormant state.

Evergreen trees like eucalyptus trees lose their leaves a few at a time over the entire year, replacing them slowly. The leaves also have a glossy/waxy coating on them that helps prevent moisture loss, so there is no need for the tree to spend energy dropping the leaves.

Fruits Produced By Gum And Eucalyptus Trees

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Keeping with our eucalyptus blue gum and non-eucalyptus sweetgum comparisons, these two trees also produce very different fruits.

Bluegum trees produce fruit that resembles a spinning topIt is narrower at the bottom, wider at the top, and capped on top. Each fruit contains several seeds, but the chances of the seeds becoming trees are pretty low.

Sweetgum trees produce strange, alien-looking fruits that are round and spiky. When on the tree, these spiky fruits are typically green. They quickly turn brown once they fall off. Each fruit carries an average of two seeds.

The timing of the fruits is another variable between these two trees. Eucalyptus trees like blue gums will usually ripen their fruit between October and March. Sounds like a weird time to be growing fruit, right? That’s because, in Australia, October is around springtime and March is the end of summer and the beginning of fall.

Sweetgums typically ripen their fruit around the same season, but in North America that is from April through September. Early fall is when you can find these spiky fruits on the ground, so be sure to wear shoes around them!

Differences In Environmental Needs Between Eucalyptus And Gum Trees

Both sweetgums and eucalyptus trees love the sun. They prefer to be in full sun but can tolerate partial shade, especially sweetgums.

Eucalyptus trees prefer soils that are well-drained with low salt content, but they can thrive in a wide range of soils and climates. For example, in Hawaii, blue gums grow in soil that is highly acidic and formed from volcanic ash. In Portugal, they grow in sandstone- and limestone-derived soils.

Sweetgums are even more adaptable than eucalyptus trees when it comes to soil conditions. They’ll thrive in swampy areas, plateaus, clay soils, and near river bottoms. Sweetgums can withstand the heat and the cold, thriving through 100°F and -5°F, respectively.

Eucalyptus blue gums are a little less tolerant of cold temperatures. They start to shiver at 30°F and cannot survive anything lower than 20°F.

Hardwood Use Of Eucalyptus And Gum Trees

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Trees are used for a lot of things that many of us take for granted: furniture, cabinets, paper, wine corks, chewing gum, and medicine like aspirin.

The fast growth rate of both eucalyptus and sweetgum trees makes them an ideal candidate for a semi-sustainable resource. In tree plantations, they can be harvested in as little as 7 years. The plan was to use these trees for furniture, railroad ties, and firewood, among other things.

Things didn’t go according to plan in California…

Millions of blue gum trees were planted in the hopes that they could be harvested for their wood and made into useful stuff. 

What was quickly discovered was that the lumber would easily split, twist, and crack. In addition to this, the wood couldn’t be properly treated, so using it for lumber or furniture was out of the question.

Despite this, blue gums are still used for windbreaks, shade, and as ornamental trees in yards. They also provide medicinal benefits and can be used as firewood.

Sweetgums are more useful in the lumber industry than eucalyptus trees. The wood does not crack or twist, so it can be used for a variety of purposes such as railroad ties, pulpwood, plywood, trim, crates, boxes, general lumber, and veneer. 

Root Differences Between Eucalyptus And Gum Trees

Roots are an important aspect of a tree. In some cases, the tree is just the tip of the iceberg, while the majority of the organism lies beneath the soils.

Eucalyptus trees like blue gum typically do not have a taproot. This is the root that grows straight down from the trunk of the tree and is used to anchor it in place. Instead, blue gums will grow a wide network of more shallow roots spreading out beneath the trunk.

Despite the lack of a taproot, blue gums can affect water resources as deep as 45 feet below the surface and as far as 100 feet away from the tree. This can often create soil erosion and lower water levels around streambeds within the tree’s vicinity.

Sweetgums are highly adaptable and can survive both with and without a taproot. They change depending on the site conditions. If sweetgums grow on windy slopes, they’ll develop a deep, strong taproot that keeps them from being uprooted by the wind.

On the other hand, if sweetgums are growing in swampy, poorly drained soils, they rarely develop taproots. Instead, they’ll grow shallow root systems that spread out rather than down.

Why Are They Called Gum Trees?

Does it have to do with chewing gum? Yep! Gum trees produce a sticky sap when the tree is injured. The sap covers the wound similar to how our skin scabs over. This allows the bark to heal without having any nasty bugs or birds trying to move inside the wound.

When the sticky sap hardens, it forms a substance that can be used as chewing gum. Back in the day, it’s said that this sap helped the settlers and soldiers at Fort Smith, Arkansas, who used the sap as a kind of candy and a way to pass the time.

Are Eucalypt And Eucalyptus The Same Thing?

While perusing the internet to quench your thirst for eucalyptus knowledge, you may come across a familiar yet strange word: eucalypt. So, what the heck is it? Is it the same as eucalyptus?

Eucalypt is a word often used to describe a group of eucalyptus trees. For example, you might hear the phrase “a eucalypt forest” which refers to a forest of eucalyptus trees. It’s also used as the plural form of eucalyptus, similar to how ‘cacti’ is the plural of cactus.

That’s All For Now

Hopefully, this article has cleared up the confusion between eucalyptus and gum trees. While most gum trees are eucalyptus trees, some are in their categories like sweetgums, black gums, and water gums.

If you are interested to learn more about the uses of gum trees, click here!

Both eucalyptus gums and non-eucalyptus gums grow quickly, making them useful for manufacturing wood products and medicines. But there are several differences between the trees. 

To recap, the major differences between the two include:

  • Leaves
  • Bark
  • Height at maturity
  • Native range
  • Growth cycle
  • Fruits
  • Environmental needs
  • Uses
  • Roots

Both trees have their pros and cons, but all in all, they are both impressively tall and fast-growing trees that give the world a little more nature to enjoy.

References

Dickinson, K., & Kirkpatrick, J. (1985). The flammability and energy content of some important plant species and fuel components in the forests of southeastern Tasmania. Journal of Biogeography12(2), 121-134. https://eprints.utas.edu.au/2698/

Lindbeck, J. M., O’Bryan, C. A., Martin, E. M., Adams, J. P., & Crandall, P. G. (2015, Jan-Jun). Sweetgum: An ancient source of beneficial compounds with modern benefits. Pharmacognosy Review9(17), 1-11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4441155/

Luu, T. C., Binkley, D., & Stape, J. L. (2013, February 01). Neighborhood uniformity increases the growth of individual Eucalyptus Trees. Forest Ecology and Management289, 90-97. https://www.sciencedirect.com/science/article/abs/pii/S0378112712005841

Myburg, A. A., Grattapaglia, D., & Schmutz, J. (2014). The genome of Eucalyptus grandis. Nature510, 356-362. https://www.nature.com/articles/nature13308

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