Thinning is a widely used tool in Australian forest management. By selectively removing trees, thinning can achieve a range of objectives – from enhancing forest health and biodiversity to improving timber production. Understanding the differences between ecological and commercial thinning is key to ensuring these objectives are met responsibly and effectively.
What is ecological thinning?
Ecological thinning is primarily used to restore or enhance ecological values. It involves reducing tree density in overcrowded areas to reduce competition for light, water, and nutrients. This process supports the growth of larger, more robust trees and encourages a diverse understorey, which in turn benefits wildlife and forest resilience.
The Biodiversity Conservation Trust of NSW notes that thinning can support understorey regeneration and the development of habitat trees¹. Trust for Nature highlights the importance of tailoring thinning to the unique characteristics of each site². According to Baker et al., reducing competition through thinning enables trees to grow more rapidly, develop habitat features such as hollows sooner, and better withstand fire stress³.
This approach contributes to a more structurally complex forest, helping it better withstand environmental pressures such as drought, disease, and fire⁴.
At the Healthy Forests Foundation, we’re particularly interested in restoring forests in areas with the highest potential habitat benefits. In many cases, this may require an initial phase of ecological thinning to create the right conditions for cultural management to resume and thrive.
What is commercial thinning?
Commercial thinning focuses on improving the quality and value of timber. Trees that are poorly formed or of lower commercial value are selectively removed to concentrate growth on those more suitable for harvesting.
Forestry Australia explains that thinning can contribute to economic, ecological, and cultural outcomes⁵. When well-planned, it helps reduce risks from fire, pests, and drought, while improving the growth rate and form of retained trees⁵. Private Forests Tasmania similarly outlines that thinning enhances timber yields by allowing more space for better-formed trees⁶. As with ecological thinning, research by Baker also supports the idea that larger trees created through thinning are more resilient to fire³.
Unlike ecological thinning, commercial thinning often results in more uniform stands, which may not support the same level of habitat diversity.
When conducted with care and over appropriate timescales, both ecological and commercial thinning can contribute to climate change mitigation. Thinning can support carbon sequestration by reducing stand-level mortality, enhancing forest structure, and enabling the growth of large, carbon-dense trees⁷. In commercial contexts, harvested wood can also displace emissions-intensive materials, contributing to net carbon benefits over time⁸.
Comparing ecological and commercial thinning
|
Feature |
Ecological Thinning |
Commercial Thinning |
| Main purpose | Enhance biodiversity and forest health |
Optimise timber quality and yield |
| Tree selection | Focus on improving ecosystem structure and function | Focus on retaining commercially valuable trees |
| Impact on structure | Promotes mixed-age, diverse forest stands | Often leads to uniform age and spacing |
| Ecological outcomes | Supports understorey growth and wildlife habitat | Varies; may reduce structural diversity |
| Environmental benefits | Improves fire resilience, habitat quality, and ecosystem function; promotes larger trees more quickly | Reduces fire risk and improves drought and pest resistance, depending on design |
| Carbon benefits | Enhances long-term carbon storage through healthy forest structure and resilience | Provides carbon benefits via wood product substitution and reduced fire emissions, if well-managed |
| Application context | Conservation and ecological restoration | Timber production and forest industry use |
Why it matters
Both ecological and commercial thinning can play a role in sustainable forest management. However, they serve different purposes and produce different outcomes. When the goal is to support biodiversity and climate resilience, ecological thinning is more appropriate. Where timber production is the priority, commercial thinning offers economic benefits – but must be carefully managed to minimise ecological impacts.
Forest management strategies should be tailored to the values and goals of each site. At the Healthy Forests Foundation, we support thinning practices that prioritise long-term forest health, respect ecological knowledge – including that of First Nations peoples – and deliver outcomes that benefit both people and nature.
References
¹ Biodiversity Conservation Trust of New South Wales 2020, Ecological thinning guidelines, NSW Government, https:
² Trust for Nature 2025, Can’t see the forest for the trees? Improving tree density for habitat, Trust for Nature, viewed 18 June 2025, https:
³ Baker, P, Fairman, T & Pascoe, J 2024, ‘Restoring logged forests doesn’t mean locking them up as “wilderness” – it means actively managing them’, The Conversation, viewed 18 June 2025, https:
⁴ Department of Biodiversity, Conservation and Attractions (DBCA) 2022, Forest management plan 2024–2033, Government of Western Australia, https:
⁵ Forestry Australia 2023, Thinning of native forest: Position statement, Forestry Australia, https:
⁶ Private Forests Tasmania 2020, Information series No. 12 – Thinning, Private Forests Tasmania, viewed 18 June 2025, https:
⁷ Keith, H et al. 2014, Managing temperate forests for carbon storage: impacts of logging versus forest protection on carbon stocks, Ecosphere, vol. 5, no. 6, pp. 1–34, viewed 20 June 2025, https:
⁸ Ximenes, F et al. 2022, A review of the impacts of sustainable harvesting, non-harvest management and wildfire on net carbon emissions from Australian native forests, Australian Forestry, vol. 85, no. 1, pp. 3–20, viewed 20 June 2025,
Active conservation