By gum! It’s Australia’s rarest and (perhaps) loneliest gum tree

The Eucalypts, sometimes known as gum trees, are the icons of Australia.

The gum tree dominates almost every terrestrial ecosystem in Australia to a greater extent than any other genus on any other continent.

With over 800 species throughout Australia’s forests, woodlands, and shrublands, they are a common sight across the country.

Do you know that they even have their own national appreciation day? On March 23, people celebrate National Eucalypt Day to celebrate the importance of eucalyptus trees.

Despite the widespread distribution of its relatives across Australia, one species of gum tree has been singled out as the loneliest in its family tree, with only six members remaining. 

Get to know the unique Mongarlowe mallee

The Mongarlowe mallee (Eucalyptus recurva) was discovered in 1985, and after the first finding, numerous searches have been done to locate any other members of the Mongarlowe mallee family.

After extensive efforts, researchers have found only six remaining Mongarlowe mallee at four sites in New South Wales, making them one of Australia’s rarest eucalyptus species.

Apart from its popular name, “Mongarlowe mallee,” this rare gum tree is also known by a more exciting name, “ice age gum.”

And here’s why.

Like other Eucalypts species, the Mongarlowe mallee can easily re-sprout from lignotubers or dormant buds.

In fact, knowing how much its lignotuber grows through time might give us a sense of how old the tree is.

Assuming that the lignotuber grows no more than 2mm each year, then the largest E. recurva gum tree is estimated to be at least 3,000 years old.

Even so, two of the other Mongarlowe mallees, if shown to be genetically similar and to have branches of the same original parent tree, might be as ancient as 13,000 years.

This seems so amazing and almost unbelievable. These trees may date back to Ancient Egypt, the pre-Roman Empire, or perhaps even earlier. That’s where they get their name, ‘ice age gum.’ 

Sadly, they are on the brink of extinction

Sounds pretty sad right?

Six of the rare Mongarlowe mallee gum trees are all that is left to ensure the species’ continued existence in the wild.

What’s more, their pollination habits and production of viable seeds have been a concerning problem for many years.

The true Mongarlowe mallee gum trees can only be produced when the tree itself is pollinated by members of its own species.

To complicate things even more, the six remaining trees are spaced far apart. Even the two closest Mongarlowe mallees are at least 40 meters apart.

Because of the immense distance between them, no pollinator is willing to make the trip, making it impossible for these gum trees to produce viable seeds.

Furthermore, the seeds fertilized with pollen from other nearby gum trees would not develop into pure Mongarlowe mallee trees but rather hybrid mixes of two species.

Only a few seedlings that seemed to be true Mongarlowe Mallee actually germinated. But sadly, none of them are strong enough to make it.

Then, because of the small number of surviving individuals and their isolated distribution in a few sites, this gum tree is very vulnerable to unexpected occurrences.

In other words, the species may have little potential to adapt to future environmental changes.

As a result, they must be closely safeguarded against wildfire, human interference, disease, extreme weather, and severe drought. The difficulty of their reproduction in the wild implies that any unfortunate plants lost via natural causes or accidents are unlikely to be replaced.

Hence, the future of this gum tree species is not so promising.

But there is hope!

While this tree might be lonely, it does get plenty of company from the humans who care about it.

Different organizations have made many efforts to protect these critically endangered plants. Volunteers and scientists attempted to cross-pollinate the two plants at Mongarlowe in 1992 to propagate the species using grafting and tissue culture techniques.

Though the first attempt was unsuccessful, they were very determined to give it another try in 2001 and 2002. Subsequently, the first viable seed was successfully made in large quantities.

Around half of the seeds germinated into what seemed to be pure Mongarlowe Mallee plants, while the other half were hybrids.

This study demonstrated that the species is not hopelessly infertile. The Australian Plant Bank has been carefully preserving the seeds for the past few years. 

This is very promising news for the recovery of this ice age gum. Like the recovery of the nearly endangered Wollemi Pine, let’s keep our fingers crossed that we’ll see this rare and unique gum tree in our gardens one day.

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