Everything You Need to Know About Acacia Trees

Everything You Need to Know About Acacia Trees

by | Dec 10, 2018

First things first, what is an acacia tree?

When you hear the word Acacia, do you think of umbrella-shaped trees in the African Savanna? Or maybe shrubs in the dry American Southwest? Or even the Australian outback? Acacias are a group of trees and shrubs with over 1,000 species and a wide range! Let’s take a quick tour of the most interesting facts about these trees!

 

Drawings of various parts of differnt Acacia species.

Drawings of various parts of different Acacia species.

 

Where do they grow?

Acacias are well adapted to deserts and tropical areas. Therefore, they have a wide distribution and are native to Australia, South Africa, the Southwestern United States, and South and Central America. Some people plant species of these trees for their attractive yellow blooms.  Because they are so diverse and fast-growing, some of these species have become invasive.

 

What do they look like?

 

Acacia seed pods

Acacia seed pods

 

Though acacias are quite diverse, they share some common characteristics. The genus Acacia is a member of the pea family (Fabaceae). This family shares the distinctive seed pods that peas, acacias and other legumes grow.

They often have many small oval leaves (called pinnate leaves) along their “leaflets.” This gives them the appearance of a double-sided comb. These leaflets attach to the main stem by a leaf stalk called a leaf petiole.

Sharp, threatening thorns protect acacias precious leaves from herbivorous (plant-eating) animals. They need these thorns in the dry environments where they grow. When it rarely rains, losing the water in your leaves can be a death sentence. This is a common strategy for desert plants.

Acacias can be shrubs or trees of all sizes. However, the large, umbrella-shaped acacias of the African Savanna are an easily recognizable image. Other acacias can be low growing groundcover or small shrubs.

Do you think you have spotted a species of acacia in your yard or on a hike? Use the PlantSnap app to identify it!

 

What are some examples of types of acacia tree?

 

Silhouette of an acacia tree with a sunset as a backdrop.

Acacia at sunset

 

Acacia senegal – Gum Arabic, Senegal Gum, Sudan Gum Arabic

This plant produces gum arabic. This resinous substance has many applications in pharmaceuticals, food science, and traditional medicine.

 

Acacia pycnantha – Golden wattle

This species of acacia is Australia’s national flower! The yellow globes of its bloom are actually many small flowers.

 

Acacia genistifolia – Spreading wattle

This low growing acacia grows white flowers in beautiful orbs.

 

What are acacia trees used for?

 

Gum arabic

 

Pile of gum arabic on blue fabric

Gum Arabic

 

A wide variety of products use gum arabic. It comes from multiple species of acacia tree and has a wide variety of applications. These include pharmaceuticals, soda, newspaper ink and even as food. The most common sources of this product is the species Acacia senegal. Many species of acacia including Acacia richardsii produce this product. Gum arabic has historically been an important part of the Sudanese economy. Currently, climate change is threatening this industry by decreasing acacias sap productions.

 

Catechu and Tannin dyes

Acacia trees including Acacia catechu can dye fabrics a dark color. This is due to extracts containing tannins and catechins. These dyes both color and preserve cloths. It is also used much like gum arabic as an emulsifier.

Hardwood

One of the most common uses of acacia is for its wood. This is because it is an extremely durable wood. It also resists water damage and scratching. Because these trees are so fast growing, harvesting acacia wood is sustainable. These features make acacia very popular for woodworking.

 

Thorny homes for ants

 

Acacia Thorns

Acacia thorns

 

Acacias have a surprising tenant on their branches! Many species of acacia have symbiotic (mutually beneficial) relationships with species of ants. The plants provide ants with food and a home in their thorns. In exchange, the ants kill bacteria, leaf-eating insects, and competing plants.

Some species of acacia form a tasty treat on their seeds. Therefore, they convince ants to carry the seeds deep into their colony. Consequently, planting the next generation of acacias! The ploy may go deeper than just a good ant snack. Research shows the plants may use oleic acid to stimulate corpse carrying behavior by the ants. As a result, the ants carry the bulky seeds home with them.

Read more about how ants and plants ended up working so closely together.

 

Food

The tall acacia trees of Africa provide an important food source to Giraffes. The silhouette of a giraffe eating the leaves of an umbrella-shaped acacia is a classic image. However, Giraffes are now facing the threat of extinction. This essential food source is becoming increasingly important to the ecology of the African savanna.

Humans have also begun using acacia trees as food. There are claims of numerous health benefits of this high fiber food. Eating too much acacia has the potential to make some people sick. So be sure to consult with your doctor before introducing acacia products into your diet!

 

Invasive acacias

Acacias provide many benefits to natural ecosystems. However, many species of acacia have begun to invade new ecosystems. This is due to their fast growth, spines, and attractive flowers.

Many species become invasive after introduction as attractive landscaping plants. For example, Acacia confusa is an example that was introduced to Hawaii for its pretty yellow flowers.

Other species have introduced for their economic value. For instance, Acacia maernsii, or black wattle, is an example that was introduced from Australia to Africa. It was introduced for commercial production of resins, timber, and medicine. Since then, the fast-growing plant has quickly become a weed. It replaces native grasses and decreases water availability.

 

Conclusion

Acacias are a diverse genus with many interesting and useful species. Whether you are a human, ant, or a giraffe, you will have no trouble falling in love with these beautiful trees.

 

23 Comments

  1. kenneth summersgill

    I keep tropical freshwater fish can acacia wood be used in the fish tank

    Reply
  2. Tania

    Is acacia harmful sor asmathic people?

    Reply
  3. K Franckeiss

    I have grown a small acasia tree from seed ,could you tell me what time of year
    does it come into leaf.

    Reply
  4. Zarina Jeena

    can tyres be use for protecting acacia in park from getting damage

    Reply
  5. TeeningaPalmen

    We truly liked this article, its really awesome. I might have a few suggestions though, but dont want to cause an argument 😀 Anyway, keep up the great work, and until next time! Regards

    Reply
  6. Mike

    I am concerned about the massive loss of leaves however there are new leaves growing
    So will.keep monitor closely
    The tree is about 18 years old. Can anyone give me advice. Is the tree dying? It has been a healthy tree other wise.

    Reply
  7. Robin Sunbeam

    This article leaves out a lot. For example, the hinges on the locks of the Erie Canal were made of Ironwood, an acacia grown in the Florida Keys. They served well as hinges due to the hardness of the greasy acacia wood.

    I learned a lot about acacia trees at a botanical garden in Florida with an entire wing dedicated to acacia trees. It was probably the botanical garden in Key West.

    Another example omitted is that some species of acacia tree are salt tolerant. They have been used successfully to reclaim farmland from the desert. The deciduous acacia trees planted at the edge of the desert drop their leaves each autumn adding humus to the soil.

    Another very important example omitted from this article is that acacias, like legumes, have nitrogen-fixing bacteria in nodules on their roots. So, the leaves take nitrogen from the air and turn it into a soluble solid, which enriches the soil.

    As a farmer, my farm animals need greens every day. When all the grasses and weeds are dried up here in sunny California, I provide acacia branches. I did learn from this article that the seeds are also edible.

    Reply
  8. Mehreen Malik

    The people of Pakistan use branches of acacia tree for cleansing of their teeth by believing that it has many medical benefits moreover, chewing of its leaves particularly in the month of March has many benefits for stomach and mouth wash. Please specify those medicines if appropriate research have carried out, if so please communicate.

    Reply
    • Afubwa Musumi

      I am interested in any research done on acacia flower extraction that a tendency aromatic scent especially during dry season flowering in eastern part of Kenya.

      Reply
  9. Dave Venables

    The ultimate fiber for humans with so many health benefits google cholesterade

    Reply
  10. Zsuinegue

    Where can I buy Acacia purpureapetala in San Diego? I see it planted everywhere but have not seen it for sale.

    Reply
  11. Joe

    Do acacia trees get their unique / iconic umbrella look solely as a result of Giraffe’s eating the leaves below?

    Reply
    • joe goshey

      I would assume that would be one of the many reasons. Plants do have a tendency to change to their environment over time, especially and repeated action that is negative to them.

      Reply
    • Casey Hofford

      Hi Joe, herbivory by giraffes definitely contributes to the shape of the African acacia trees. This happens both through evolutionary mechanisms and the pruning by hungry giraffes!

      Reply
  12. Linda Smith

    Hi – we have an Australian Acacia tree in our back yard. It was here when we moved into our home last year and we believe it is about 13-14 years old. We have noticed a sap like substance running down the tree this winter and also it’s developed several several inverted V notches up and down its trunk. Is the tree distressed or is this normal? We live in AZ.

    Reply
    • Sheila

      To Linda in AZ. I too live in AZ and saw your comment. I saw a special on the acacia tree back in the later 90’s. I believe it was on the Discovery channel. I have NEVER forgotten it. I wish I could see it again. I don’t remember if it was all about Africa, or just about the tree, but they talked about this to for about an hour. This tree, (over many, many, many years) actually made subtle changes to ITSELF, to protect itself from animals eating on it and from it. This is how it ended up with the iconic umbrella shape of today. This, in addition to, all the AMAZING characteristics this tree possesses. It’s almost as if this tree, “thinks” for itself. That show, that evening about this tree made quite an impact on me.I wish I could find it again. I just wanted tell Linda from AZ how blessed they are to have one. I don’t have an answer for your question, however wanted to share my story with you. I found this site trying to tell my boyfriend all about this tree. AMAZING! JUST AMAZING! I hope you get any info needed to protect and save it, however, it may just save itself.

      Reply
      • RICK BOYD

        “It’s almost as if this tree, “thinks” for itself.”

        Read a book titled “The Secret Life of Plants” years ago. One of my all time favorite books. Should be required reading for everyone!

        Well worth your time to locate and read for yourself…

        Reply
    • Sanele

      It a different story for me with acacia trees, I am so allergic to then unbearable n I need help

      Reply
  13. Zachry Fisher

    what effect do we have on acacia trees (global warming pollution ect.)

    Reply
  14. Luol Nyok

    Are acacias trees protected and what is the best way to protect them?

    Reply
  15. Grant

    Are acacias trees protected

    Reply
    • Robin Sunbeam

      Depends on the species and the local jurisdiction. In Northern California, the Black Locust is an invasive species and local governments don’t require permits to cut them down.

      Reply

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