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Plant Focus

Update on the Valonia Oak Restoration Project

An article published on the IOS website in December 2014 told of the sorry state of an old plantation of Quercus macrolepis subsp. ithaburensis in Castlemaine, Victoria, Australia (click here to read the original article). Recently we received an update on the project from Peter Marshall, a forest mycologist who was able to determine the reason the trees were dying and to advise on what steps to take to save the trees. Here is an article from the Castlemaine Mail telling the story (click on the image to enlarge), and below, Peter's comments.


Castlemaine Mail Article

Peter Marshall's comments:

"I am a forest mycologist running a thousand acres of native forest, plantations, restored wetlands, and an arboretum in Southern Highlands, New South Wales, Australia. Some years ago I was on a seed hunting trip in 2013 and discovered the skeletons of Cunnack’s Valonia Oaks. Of 14 originals 11 had recently died, two were very sick, and one near dead.

The authorities, including the local council, Heritage Vic, and IDS had no idea what was wrong and had not been able to save the trees. The situation was grave, so I enlisted the help of teacher Terry Willis and the great little kids of Winters Flat Primary School.

Students from Winters Flat Primary School and garden specialist Terry Willis plant a seedling
Students from Winters Flat Primary School and garden specialist Terry Willis plant a Quercus macrolepis subsp. ithaburensis seedling as part of the Valonia Oak Restoration Project. Photo © Castlemaine Mail

The problem was soil compaction, which had asphyxiated the mycorrhizal fungi. Trees were starving of O2 and nutrients. The solution was to decompact the root plates, reinoculate with mycorrhiza in a biochar substrate and put down a thick mulch of rice hulls to reduce soil temperature on summer afternoons.

The trees have come back to life and are fruiting again.

We had a fun day replanting, with talks about the heritage, planting, and pruning techniques. Terry and the kids have a brilliant kitchen garden and provided morning tea. The Q. macrolepis acorn-cup-shaped chocolate cake was a highlight.

The site has been deep ripped, mulched, and is now off limits to hundreds of little compacting school shoes."