River Red Gum - Eucalyptus camuldulensis

The River Red Gum tree (species name: Eucalyptus camuldulensis) is a common "Gum" tree along river beds across inland Australia and is also a popular plantation tree in many other parts of the world. In Southern Europe and Northern Africa the River Red Gum can be found growing spontaneously along water ways downstream from where it has been planted in plantations. The term "Red" in its common name refers to the color of its wood when milled.
Like many other Eucalyptus trees the flowers of the River Red Gum have a cone shaped cap that protects the flower while it is forming and then pops off when the flower is ready to "unfold" as can be seen in the images below.

The individual flowers are arranged in small clusters that themselves are star shaped like the one above. The picture below shows some of the detached "caps" that pop off the end of the flower buds.
After the flowers have wilted and fallen off there remains on the tree a cluster of small "fruits" that have valve like openings on the end in a star like shape. As you can see in the image below these star-like openings can have 3-6 points. The seeds inside these small fruits are released through these openings. These woody, dried fruits can be easily found at the base of the River Red Gum trees and is a good way to help identify the tree and distinguish it from other Gums.

The large tree in the image below is a tree in the "Molino de Inca" botanical garden in Torremolinos, Spain (along the Southern "Sun Coast"). It is quite common to find large specimens of the Eucalyptus camuldulensis in botanical gardens in Spain.

The leaves of the River Red Gum are long and slender with a pronounced central vein. They measure about 4-7 inches in length and about 1 inch in width.


Some other Gum trees that I have blogged about are...
Coral Gum Tree - Eucaluptus Torquata
Tasmanian Blue Gum - Eucalyptus Globulus
What makes Eucalyptus fires dangerous

What makes Eucalyptus fires in Australia so dangerous?

With the recent news coming out of Southern Australia one is left asking the question "What makes the forest fires in Southern Australia so dangerous and deadly?"

Here are some answers that I have found while reading up on this...

1. Dry conditions - Australia has a lot of dry areas. Most of the Eucalyptus tree species have adapted to these dry conditions and some of them can grow in almost desert like conditions. Just this alone is a receipt for fires, trees and very dry conditions.
2. Peeling bark - Eucalyptus trees have smooth bark that peels off in long strips and falls to the ground. This gives any fire an abundance of material to burn on the ground as it spreads.
3. Flammable leaves - Eucalyptus leaves are very flammable adding to the material on the ground to keep the fire going.
4. Dependent on fires - Some species of Eucalyptus can form thickets and actually need fires to clear out the competition.
5. Flammable oils - ome Eucalyptus trees such as the "Blue Gum" produce flammable oils that make the trees either burn with incredible intensity or even explode. The Blue Gum has been called "Gasoline trees" for this reason.
   

a large Blue Gum tree

a quote from www.audubonmagazine.org...

Of the many eucalyptus species that evolved with fire, none is more incendiary than blue gum. "Gasoline trees," firefighters call them. Fire doesn't kill blue gums. Rather, they depend on fire to open their seedpods and clear out the competition. And they promote fire with their prolific combustible oil, copious litter, and long shreds of hanging bark designed to carry flames to the crowns. Blue gum eucalyptus doesn't just burn, it explodes, sending firebrands and seeds shooting hundreds of feet in all directions. Living next to one of these trees is like living next to a fireworks factory staffed by chain-smokers.

Blue Gum bark

Tasmanian Blue Gum - Eucalyptus globulus

The Tasmanian Blue Gum (Eucalyptus globulus Labil.) is a large tree species native to southern Australia. It also goes by the common names Southern Blue Gum and Blue Gum Eucalyptus. The tree in the image above is located in a botanical garden in Malaga, Spain. I measured the trunk of this tree at 1.6 meters wide at the base. This Eucalyptus tree species is one of the most common in Spain. The Tasmanian Blue Gum was "discovered" and introduced to the world by Citizen Labillardière in 1792. This was the tree species by which the Eucalyptus genus became known to the world.
The "fruits" of the Tasmanian Blue Gum are fairly large as far as Gum trees go. The tape measure in the image above is in centimeters and as you can see these woody, button shaped fruits measure about 2-3 cm across and 1-1.5 deep. The star shaped openings on the front are valves that release the seeds. In this picture you can see that the number of valves can vary (from three to six are possible). The "globulus" part of the Latin species name comes from the "small button" shape of the fruits.
One interesting aspect of this tree species is the pronounced difference between its juvenile, intermediate and adult leaves. The picture above shows a pair of new juvenile leaves that have formed on a new branch at the base of a large tree. In the image below you can see more juvenile leaves on another somewhat larger new stem.

In the next picture you can see how the secondary branches grow from the base of the juvenile leaves.
The picture below gives an idea of the difference in shape and size between the juvenile and adult leaves. you can also see that the adult leaves do not grow in pairs but rather are alternate.

The bark of the Tasmanian Blue Gum can be gray-blue or reddish and often has pronounced dimples on the larger trunks.

For more information on this tree species consult Eucalyptologics where you will find lots of information and resources on Eucalyptus cultivation around the world.