Soil is critical to forest productivity, providing the resources that support the growth of trees in nurseries and forests. Scion’s soil scientists are using genetic, molecular, and chemical analyses to directly link soil processes to the productivity and sustainability of New Zealand’s planted forests. This work is proving that we can use our understanding of soil processes to minimise the use of expensive chemical fertilisers and maximise forest growth.

Research funded by industry through the Forest Growers Levy Trust and Growing Confidence in Forestry’s Future programme has resulted in some key findings in soil science. We can now show the importance of nursery conditions in growing trees and how the influence of soil properties in the nursery can effect tree growth and performance for up to six years in the forest. This has created potential for significant improvement in forest volume by management of soil in the nursery.

Dr Simeon Smaill, microbiologist and project leader, says, “The team has developed new treatments that can enhance the activity of soil microbes and benefit tree performance and forest sustainability. For example, continued positive results from a new soil nitrogen treatment has shown that it is possible to reduce chemical inputs without compromising seedling growth and survival.”

The work being carried out by the team at Scion is opening up opportunities we haven’t been able to explore in the past. We see real opportunity in the soil management area and with the help of Simeon and others we are now moving quickly from science based trials to large operational trials with the expectation that enhanced soil management will become a key part of our productivity tool box.  - Ian Hinton, Technical Manager, Timberlands Limited

Scientists at Scion have also continued to develop and improve our Nutrient Balance Model (NuBalM) to predict how nutrients affect growth at the stand level, the effect that management decisions could have, and how to ensure soil quality is maintained to support future rotations. This work has been ongoing for 25 years and data from our long-term site productivity trials has enabled Scion and the forestry sector to improve NuBalM and test its accuracy over multiple locations across the country. It has also been used to prove the value of retaining harvest residue on site for long-term soil fertility.

Major forestry companies are increasingly using Scion’s soil-based knowledge and expertise to better manage their forest estates.

Ian Hinton, Technical Manager at Timberlands Limited, says, “The work being carried out by the team at Scion is opening up opportunities we haven’t been able to explore in the past. We see real opportunity in the soil management area and with the help of Simeon and others we are now moving quickly from science based trials to large operational trials with the expectation that enhanced soil management will become a key part of our productivity tool box.”

The deeper we dig, the more we reveal the untapped potential for managing soil, as an integral and living part of the forest ecosystem, to increase both the productivity and sustainability of New Zealand’s forestry estate.

Collaborators: Timberlands, Rayonier

Investment: Ministry of Business, Innovation and Employment, Forest Growers Levy Trust