The science of soil

Published in our 2023 Annual Review

Sustainable forestry requires a careful balance of environmental responsibility and productivity.

OneFortyOne employs a range of methods to monitor the impact and effectiveness and sustainability of soil treatments.

The Natural Landscape and Soil Management

The natural landscapes of the Green Triangle are a series of limestone crests interspersed with flat vales. The soils in which we grow our pine trees are mostly neutral pH, grey and brown sands on lower slopes and flats, with alkaline red loams on the limestone outcrops.

The clay flats in between were once occupied by cropping and grazing.

Lessons learned

Forest growers in the past learned hard lessons about the importance of organic matter in the surface layer of the sands. Burning post-harvest slash was discovered to release nutrients to the atmosphere and cause organic matter to be lost, resulting in lower second rotation growth rates. This realisation led to current silvicultural practices that retain harvesting slash on site and add nutrients as necessary to maintain or enhance carbon and nutrient levels in soil.

Weed Control

Weed competition also slowed the rate of early tree growth until canopy closure, which cost a great deal of wood growth over the rotation. To combat this, intensive methods of weed control were developed; some were cultural and management based, but weeds were primarily controlled by using chemical herbicides.

Continuous Monitoring and Future Focus

Monitoring is crucial to the way we work and OneFortyOne’s philosophy of continuous improvement. Soil carbon, nutrients, chemistry and water tables are monitored throughout the growing cycle. We monitor surface water runoff from new plantations to ensure that herbicides used in the establishment process don’t escape into the surrounding environment.

Up to four times each year, we conduct soil analysis in the nursery and plantations, and foliar analysis to assess nutrient uptake and guide fertiliser planning. Out in the field, we keep a close eye on the quality of our field water sources, particularly the pH, and monitor the water table at POW Lane daily.

In 2022, platinum plots were installed to regularly measure the nutrition and water cycle in 10 Permanent Sample Plots (PSP), with positive results already observed at the Springs Cave PSP.

Looking ahead, OneFortyOne will focus on the stability of native forest inliers. In addition to our biodiversity monitoring study an additional study will investigate the effects of the past century of forestry on soil chemistry and structure through paired plots in plantations and adjacent native forests.

Research and Development

Desmond Stackpole, Research Manager, Green Triangle, has a particular interest in the deployment of our best genotypes to plantations.

“We will also conduct fertiliser trials and test herbicides to try to decrease the rates of chemicals we use, and monitor the survival rates of the trees.

In the 2022 season, the Estate Team set up survival monitoring plots for regular inspection to see when mortality events occur.

Our aim is always to improve the productivity of the forests.”