You've heard about the birds and the bees, but do you know about the pollen and the trees?
An elite selection of trees in South Australia have been hard at work during baby-making season to create better genetics for plantation timber.
The radiata pine trees have been chosen for Australia's only softwood breeding research and gene conservation site located in Mount Gambier and run by national forestry cooperative Tree Breeding Australia.
General manager Tony McRae said the aim of the site was selective breeding for plantation trees.
"They're not just any babies, they're coming from the very best parents that have very good characteristics," he said.
"Some of the babies will have even better genes than their parents, so that will enable us to identify those and increase the productivity in future generations of plantations."
However, these seeds will not make it to commercial plantations; instead, they will be planted in trials across the nation to track their genetic success.
Researchers study the trees over their life for attributes such as wood quality and growth rate, and the information will further develop genetics available for plantation companies.
"We plant up to 9,500 seeds [in each trial] which are genetically unique, coming from some 300 different families," Dr McRae said.
"We will combine that data with trials which have been planted in previous years or decades … we're generating new data on a daily basis."
He said that from there, the best genetics are brought back to the breeding site.
"Out of the hundreds of thousands that we have in the trials, we might bring in 30 to 50 new parents, so we know the good parents based on performance out in the trials."
When the pollen meets the trees
It takes roughly two years to get viable seeds, from first pollination until pinecones are harvested, and pollination can only happen in a narrow six-week window.
During this time, pine technicians such as David McKersie find opened flowers on the trees and place paper bags over them — protecting them from wild pollen.
When scales on the flower begin to open, specific pollen is injected into the bag via resealable holes.
"It's usually about six days [after bagging] until we do the first pollination, and then we do three pollinations in four-day intervals," Mr McKersie said.
The bag is removed around six weeks later after the flower has closed and a pinecone is left to form.
"Then we wait two years, we take the cones from the trees, dry them, extract the seed … and then it goes into next year's trials," he said.
Each cone averages 40 seeds but that does not guarantee a high yield.
"Around 40-45 per cent of initial flowers bagged actually survive through to extraction," Mr McKersie said.
"Even if they do, it's actually the viable seed you get out at the end [that matters], because you may have a cone full of seed or the seed may be rubbish.
"Whether that's due to the pollen, frost of any other condition is speculation."
Branching out
Dr McRae said growing conditions improve the chances of success.
"The very important thing is to choose a site where the environment is conducive to flowering and seed production; Mount Gambier is reasonably mild," he said.
While the genetics start in the Limestone Coast, the data is accessible for member forestry companies across the nation.
"We consolidate that data into an index which will represent the value of any particular genotype or tree for their particular situation when they grow them in a commercial setting," Dr McRae said.
"By growing better and using better genetics, you can produce more wood from the same unit area for the same resources that you input.
"Without questions, trees that we grow today would be around $3,000 per hectare [more efficient] compared to what would be in ground in the previous rotation."
