Hybrid holds up within forestry trial

For the first time globally, a stand of hybrid P. radiata and P. attenuata pine trees has been milled – allowing scientists to compare its wood qualities against two purebred species.

The hybrid stand (a cross of P. radiata and P. attenuata) from the Ribbonwood Station trial was milled recently by Radiata Pine Breeding Company Limited (RPBC). RPBC contracted the project’s co-authors Marco Lausberg (Wood Quality Consulting) and Jonathan Harrington to complete the study.

The hybrid conversation has been in the production equation because of the trees’ potential tolerance of high-country climates – including their ability to handle snow loading – which is where P. radiata has historically faltered.

The trials were originally planted in 1998 and when the trial was harvested in 2025, it afforded RPBC the opportunity to undertake direct measurements of wood properties, and to verify earlier analysis.

In all, 92 butt logs, including examples of the three species – the hybrid, P. radiata, and P. attenuata trees – were processed at Niagara sawmill in Winton, Southland. The focus of the milling study was to compare the wood quality across all three species.

Volume and quality

Marco said the stand was well-sited – 485m (591 feet) above sea level – to definitively test the hybrid. When the farm manager wanted to clear the stand, RPBC moved quickly, taking the opportunity to validate its results in a sawmill for the first time.

“I think we had double the volume of logs in terms of acceptable sawlogs in the trial,” Marco said. “The hybrid tree was much, much better in terms of growth and form. We had trouble really getting nice, pure P. radiata and pure P. attenuata sawlogs from that site just because they had been so badly hammered by snow. I had to warn the sawmill that the logs coming from those trees were ugly, and for them not to expect normal log quality.”

The results revealed higher than average log velocity and board stiffness from the hybrid logs.

“The results give us confidence. If they are sited well, no-one is going to go backwards on the wood properties when they use the hybrids,” Marco said.

He also took the time to ask the mill staff what they thought of the logs.

“They couldn’t tell any difference between the hybrid and the pure P. radiata or P. attenuata in their appearance because visually it blended in with the normal radiata in-feed resource,” Marco said. “The only comment they had – and, this is more interesting than useful, they said the hybrid smelled different.”

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Source & image credit: Radiata Pine Breeding Company (RPBC)