Gum Trees

What are you referring to with the term "gum trees?"

There are several species that produce a rubbery sap like gum, two of which are eucalyptus and rubber trees.

Why do you ask? Are you an advisor for the forestry industry?

prikok's profile shows s/he comes from Melbourne (Aus).

I'd guess s/he'd be talking about what we know as gum trees - i.e., eucalyptus.

Can't answer the question, though.

1. timber, no matter what type of tree, is one of the most environmentally sustainable resources as long as old growth forest is not removed to make way for forestry plantations. remember that everything in terms of wood taken away from a site must be replaced usually by the use of fertiliser

2. Trees store carbon by converting sunlight, through photo synthesis, and water, as lignin. lignin is the primary cell stucture of wood.

3. Certain types of australian eucalypt are favored for forestry because of their fast growth, apical dominance (straightness) and density.

Eucalypts can use many litres of water per day, lowering water tables and greatly assisting in reducing salinty.
Eucalypts are evolutionally adapted to the Australian environment.
It costs a lot of money to grow trees
Fast growth means a farmer and/or investor can get a return on his investment in a reasonable time frame around 20 years for some types of timber, less for the fastest types.
Cattle and or sheep can be grazed within a well designed agroforestry plantation. thus increasing investment returns after a period of time.

A fantastic resource for you to learn more about agroforestry in Australia is
http://www.agroforestry.net.au/main.asp?_=Australian%20Agroforestry

Another excellent resource is The Department of Primary Industries. you can call them and they will snd material to you or have a look at some of the many resource papers available here.
http://www.dpi.vic.gov.au/dpi/nreninf.nsf/childdocs/-1C62D26CD3AF6FE44A2568B300051289-0A38C6F4DA19A236CA256BC80005ACBD?open

From Wikipedia, the free encyclopedia

"...Eucalyptus is a diverse genus of flowering trees (and a few shrubs) in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia. There are more than 700 species of Eucalyptus, mostly native to Australia, and a very small number are found in adjacent areas of New Guinea and Indonesia and one as far north as the Philippine archipelago and Taiwan. Only 15 species occur outside Australia, and only 9 do not occur in Australia. Species of Eucalyptus are cultivated throughout the tropics and subtropics including the Americas, Europe, Africa, the Mediterranean Basin, the Middle East, China and the Indian Subcontinent."

Evidently, in the fight against malaria, the use of eucalypts for swamp draining was recognised in the nineteenth century and they were planted all over the world for this purpose. I remember seeing groves in Greece and Kenya. Also, young saplings were used in Kenya to make scaffolding for buildings.

Kookaburra [Australian bird] sits in the old gum tree


a lttle background music for reading the posts on this thread

Gum trees can be found from North Africa and Spain to Papua New Guinea. Unfortunately, they will absorb as much moisture as they can get and are great for drying out the soil. In Florida, where they were introduced to dry out the swamps, people have since changed their minds. It is such a fast growing tree in its early stages that removing them will probably never happen unless vast sums are spent with no guarantee of success.

Previous attempts to use them as furniture have been unsuccessful as they are very hard on tools and this made them uneconomical. Recent developments (last 30 yrs) have changed this, and it is very surprising to see a chair leg as thin as steel but made out of wood.

Specially selected species are used for their wood, but most gum trees are unsuitable.

I just noticed this. Trees increase salinity in soil by using the water and leaving the salt. Without the trees, rain water absorbs the salts and carries it down to the water table. The whole greenie idea that cutting down the trees increases the salinity is exactly wrong.

Do you know a map of the worldwide distribution of eucalypts? I assume that Australia, with the largets number of species, is somehow the place of origin of the Angophorans and Eucalypts. I can see the distribution about the Asian and African Continents and The S and N Ameicas (at least the tropical and tropical tempereate zones). I could never figure out how they got to the Mediterranean climate of California (unless of course all these trees were imported by Spaniards or else they came North when Panama smacked back into North America.
SO either Eucalypts got to California by
1 human distribution

2nat distribution via Africa prior to the splitting of PAnga 130 milo years ago
or
3Distribution to the North from South AMerica when SOuth AMerica "Rejoined" North AMerica from 15 to 3 million years ago

From the same Wikipedia article:
California.
In the 1850s, Eucalyptus trees were introduced to California by Australians during the California Gold Rush. Much of California has a similar climate to parts of Australia. By the early 1900s, thousands of acres of eucalypts were planted with the encouragement of the state government. It was hoped that they would provide a renewable source of timber for construction, furniture making and railroad ties. It was soon found that for the latter purpose eucalyptus was particularly unsuitable, as the ties made from eucalyptus had a tendency to twist while drying, and the dried ties were so tough that it was nearly impossible to hammer rail spikes into them.

"They went on to note that the promise of eucalyptus in California was based on the old virgin forests of Australia. This was a mistake as the young trees being harvested in California could not compare in quality to the centuries-old eucalyptus timber of Australia. It reacted differently to harvest. The older trees didn't split or warp as the infant California crop did. There was a vast difference between the two, and this would doom the California eucalyptus industry."[23]

One way in which the eucalyptus, mainly the blue gum E. globulus, proved valuable in California was in providing windbreaks for highways, orange groves, and other farms in the mostly treeless central part of the state. They are also admired as shade and ornamental trees in many cities and gardens.

Eucalyptus forests in California have been criticised because they compete with native plants and do not support native animals. Fire is also a problem. The 1991 Oakland Hills firestorm which destroyed almost 3,000 homes and killed 25 people was partly fueled by large numbers of eucalypts close to the houses.[24]

In some parts of California, eucalypt forests are being removed and native trees and plants restored. Individuals have also illegally destroyed some trees and are suspected of introducing insect pests from Australia which attack the trees.[25]

Eucalyptus trees do exceptionally well in the Pacific Northwest: Washington, Oregon and parts of British Columbia.

Excellent. I really thank you for that information cause , if they were there by natural colonization it didnt make any sense unless it was via Mexico and the South.

I hate the damn things cause there are whole areas in California (like half moon bay) that smell like cat piss

That's interesting! The road between Nairobi town centre and my apartment went through a grove of eucalypts. After rain it gave off a most beautiful smell, nothing at all like cat's piss.