The ever-popular leucaena pasture is being touted as the next big thing in forestry production for Queensland.
Already widely used in both irrigated and dryland grazing operations, leucaena is now promising itself as a rapid growing hardwood with good economic returns and notable environmental benefits.
Speaking at a Leucaena Network meeting in Rockhampton last week, executive office officer of the group, Keith McLaughlin, said leucaena could be the answer to replacing the locked up areas of hardwood forests in Queensland.
And considering the nitrogen-fixing ability of the tree and its grazing potential, he said timber production was an option to consider and was worthy of having a steering committee.
“Perhaps in the future we will, with data, be able to claim we have not just an environmentally friendly system but an environmentally enhancing system,” Mr McLaughlin said.
But there are hurdles to overcome.
Growing leucaena as timber requires different management to grazing, with many supporters believing the two to be exclusive of each other.
Meanwhile, many critics of leucaena have described it as little more than a weed.
The plant can be found on numerous roadsides and waterways, despite continued council efforts to eradicate it.
However, visiting US leucaena expert, James Brewbaker, told last week’s meeting that these challenges could be overcome.
He agreed that that it would not be ideal to graze leucaena and grow it for timber simultaneously, but said that sterile lines would overcome the concern of leucaena becoming a weed.
“Sterility is extremely important,” Dr Brewbaker said. “We have the reasonable concerns to consider of those who work in the invasive species study areas.
“We recognise that as plants and insects have gone around the world often they have become invasive when removed from their normal pests and integration.
“That is certainly true of the wild and common leucaena, but I emphasise that this is one variety of one species only.
“There is no evidence that any of the other 21 species of leucaena are invasive.”
Dr Brewbaker – who works at the University of Hawaii – added that sterile lines would also be more productive.
As graziers growing leucaena would know, energy the plant puts into seed pod production is energy that it could otherwise put into leaves or wood.
Thus, when leaves and wood are the objective, energy spent on producing seedpods is wasted energy.
“For Queensland we want highly sterile or completely sterile lines like banana trees, or lines that are self-sterile so that the seediness is minimised.
“My main reason for that is not the concern about the invasiveness, but when we produce seeds we waste energy. We want the growth in the timber.”
He also added that the success of such a project would also depend on marketing and labelling.
“It is a very hard wood of a very hard quality, but at the moment it doesn’t have a name.
“If it had a name like teak it wouldn’t be a problem. But in the future it is going to be more popular as the teaks and rosewoods of the tropics decline.”
Meanwhile, Mr McLaughlin said that while sterility was not important in current grazing situations, he acknowledged it would open doors for the plant to be grown more widely in the future.
“Sterility is not needed in grazing where best practice is followed. But it is definitely needed where there is limited grazing and high, inaccessible seeding growth.”
He said sterility would be of benefit particularly on floodplain areas; for use by mining companies; on Native Title lands; and overseas, including interest from Sudan and Mozambique.
A steering committee has now been established for the project, although visitors to last week’s meeting agreed that it remained uncertain exactly how profitable leucaena timber would be.
While it would likely require irrigation to establish a decent plantation, one benefit of the tree is that it can be ratooned to produce several crops after cutting.