Researchers investigating pasture systems that grow in conjunction with commercial timber, find no loss of daily weight gain in cattle, running with the benefits of trees.
In a project title Steak n Wood, five years' worth of investigations are being co-funded by Meat and Livestock Australia with Queensland Department of Agriculture and Fisheries and findings point to profit from the more diverse enterprise.
Beyond shade for welfare there are carbon gains - sequestered in trees and soil - adding to the soil and environmental diversity.
Leading the research is Dr Nahuel Pachas, QDAF, who advocates for the integration of trees for timber production in grazing land without affecting the livestock productivity. "This practice is known as Silvopastoral systems, where trees, pasture and cattle can coexist in the same unit of land," he says. "Together they produce timber and beef and there are co-benefits, such as carbon sequestration, shade for animals, reducing erosion and increasing biodiversity.
At Dunrobin's Super Forest Plantation at Sextonville via Kyogle, a silvopastoral system is being evaluated for its co-production.
Species of durable hardwood include Gympie messmate, Spotted gum, Grey gum and Grey ironbark growing over a mixture of 60 per cent grasses (Gatton Panic, Brachiaria, Rhodes grass) with 40pc legumes including Caatinga stylo and Wynn cassia.
Prior work has shown success with broad-leafed paspalum at Sextonville, part of the Super Forest Plantations enterprise, where white Brahman cows put to Hereford and Angus bulls graze under canopies and between the rows.
Dr Pachas, working with Luke Danaher from the department, with input from University of the Sunshine Coast and the MLA, says trials highlight efficient grazing potential in alleyways between trees.
Tropical C4 grasses have a requirement for light, while C3 legumes tend to be shade tolerant.
"We are finding that a 20m alley gives a good balance of trees and grass," he says, highlighting a longer-term research project at Gayndah, Qld, where electric fences are used to graze the alleys when trees are young.
"We are finding there is no difference in daily weight gain between cattle grazed with trees compared to our control site - both about 0.6kg/day average during 295 days," he said.
"Of course you need to adjust the numbers of animals that are grazing, or spending your forests budget."
At the Gayndah plot cross-bred cattle are brought to feeder weight of 400kg on a combination of buffel grass and stylo.
At Sextonville, where trees were planted in blocks, rather than alleys, calves are sold as weaners, same as on neighbouring properties. New work is looking at thinning trees to allow more light into the understorey.
Dr Pachas says trials are showing that an ideal density of trees in a "silvopastoral" system is around 200 to 500 stems per hectare depending on the production aim and timber market, with the aim of encouraging pasture growth rather than setting areas of trees aside as a "woodlot".
"The alley configuration is more flexible," he says.
"It gives us a good balance of trees and grasses without compromising livestock production.
"We are aiming to show that producers can diversify their farm income, and sequester carbon on trees to help offsetting their carbon emission, with the forecast for the hardwood timber market set to increase," he says.
"This is a great opportunity to promote this system as Australia imports 60pc of its timber."
Dr Pachas points out the experiment covers 14 sites north to Rockhampton, Qld, with at least 750mm of annual rain on land deemed lower production value.
"We particularly want to highlight the opportunity to convert a use of degraded land to silvopastoral systems ," he said.
A trial plot at Mirianvale, Qld, with 11 species of grass and five different types of trees, using paired rows of trees (5m between rows and 3m within trees) and 20m alley at 267stems/ha, had proven to be a "good initial tree density" for beef producers who are willing to integrate trees on farm.
"With trees, a producer can mitigate their emissions while sequestering carbon.
"Trees help producers become carbon neutral while providing diversity of production and helping make farmers resilient to climate change.
"The shade also helps with animal welfare."
Other aspects of the trial will measure water quality within open pasture and under shade while biodiversity populations will be compared at Gayndah site.
Super Forests Plantations manager Mark Wright, who helped develop the enterprise, says cattle under trees are an important "silvicultural tool".
"We can maintain the under storey while reducing fire fuel loads," he says.
"It's an important part of our management."
On another local timber plantation managed by Super Forest Plantations the use of broad-leafed paspalum and Shaw Creeping Vigna allowed the bullock-only country to run breeders. Now, reports livestock manager Trevor McKenna, who has experimented with the dual system for a dozen years, stocking density has doubled.
"I am not in favour of blanketing country with trees," says Mr Wright.
"On the alluvial flood plain it is not appropriate. Trees fail in those environments. But they grow great grass."
