A Karri forest near Pemberton in Western Australia, with an unsealed road running through it.

Plantation forests in streamside management zones: multiple benefits

This 101-page report reviews the water quality and biodiversity effects of using plantation forests in streamside management zones on cleared farmland.

  • 29 January 2012 | Updated 13 January 2012

Land cleared of native vegetation and used for agriculture generally has low biodiversity and poor stream water quality.  Where livestock have access to streams, serious degradation can occur. Improvements in water quality and biodiversity can be achieved by excluding stock access using fences, but any streamside management zone (SMZ) will still require management, e.g. for weeds.

One income-generating option for this zone is to use it for wood production and carbon sequestration. Being adjacent to a stream though requires careful plantation management to avoid adverse effects on soil and water. This practice is not yet adopted widely in Australia, partly because of reservations about managing plantations next to streams.

The report concludes that the plantation establishment and harvesting phases present a low risk to environmental values if appropriately managed.

Review results

This report shows that managers of agricultural landscapes can be reassured that forested and grassed SMZs can be successfully integrated into farming operations for multiple benefits.

Research indicates that establishing and harvesting plantation forests in SMZs is possible without risking water quality, where appropriately managed. In addition, water quality improved within a year of establishing an SMZ plantation.

Several examples from other countries are also provided where plantations are routinely harvested in these zones in accordance with codes of practice designed to protect environmental values.

Overall, this review furthers the understanding of the functions and benefits of SMZs and provides a guide for their incorporation into agricultural, forestry, and urban landscapes.

Remaining constraints and questions

Major constraints to the wider adoption of this practice are the initial cost of establishment (particularly fencing) and the lack of confidence among farmers in how to manage plantations for wood and carbon values.

Another potential concern is that water use by trees might reduce ground water levels and steam flows. Research is continuing to quantify the importance of this risk to water availability in different environments, but the size and management of SMZs can probably be adjusted to keep this risk well-within an acceptable level.

Find out more about research in the Sustainable Agriculture Flagship.

SMZs are also known as buffer strips, filter strips, riparian zones, riparian buffers, riparian management zones, wetlands, greenways,  and grassed waterways. A discussion of these definitions is provided in the report.