Since the mid 1990s, there has been a growing community concern about the noticeable decline in the health of tuart trees south of Mandurah. The State Government's Tuart Response Group seeks to establish a partnership with local communities to plan and manage the conservation and protection of tuart trees and ecosystems, and to investigate the causes of their decline.

Tuart trees grow along a 400-kilometre band from Jurien Bay, on the northern margin of the Swan Coastal Plain, to the Sabina River, just east of Busselton.

They are generally confined to limy or limestone soils close to the coast. It is estimated that before Europeans arrived there were more than 111,600 hectares of tuart woodland. Most of these were subsequently cleared for agriculture and urban development and it is estimated that only 35 per cent remains.

Tuart conservation

Most tuart woodlands are now found at Ludlow, Yanchep and Yalgorup National Parks. Significant tuart woodlands are also conserved in Bold Park and Kings Park, in State Forest at Myalup and McLarty, and in unallocated Crown land and Bush Forever sites at Yanchep, Woodman Point, Port Kennedy and the Harvey Estuary. Smaller remnants of tuart are scattered across its natural range from Jurien to south of Busselton.

About 67 per cent of the existing tuarts are on freehold land.

Tuart's vegetation community occurrence has been reduced by more than 65 per cent due to urban, industrial and agricultural development. Remaining tuart woodlands have been disturbed by grazing, altered fire regimes and past timber harvesting. Some approved clearing of tuart woodlands continues for urban and industrial land uses, road construction and the development of public infrastructure.

The values of tuart woodlands include conserving biodiversity, protecting ecosystem function and providing connectivity between remnant vegetation. Tuart woodlands provide important landscape, cultural, social and economic values. Processes that threaten the integrity of tuart values include hobitat loss, fragmentation and alteration caused by changes in natural and human induced vegetation disturbance regimes.

Tuart health

In recent years, tuart woodlands between Mandurah and Preston Beach have suffered a severe decline, linked with heavy infestation by wood-boring and de-foliating insects. Research is underway in the areas of:

• root health;
• soil microbiol communities;
• soil and nutrient supply and uptake;
• water relations;
• and how these have been modified by:
  • forest management, especially the use of pine;
  • accumulation of litter; and
  • change in understorey structure.

Tuart Atlas

The production of the Tuart Atlas, an essential first stage in this ‘strategy' development, involved the digital capture of data on tuart occurrence, overstorey density and understorey condition, from high-resolution digital aerial colour photography. The mapping presented in the ‘atlas' represents the most up-to-date and accurate assessment of tuart woodlands over its natural range. It estimates the total area of tuart woodlands remaining to be 30,311 hectares.

Earlier mapping of tuart's dominant structural ecosystems estimated the current extent of tuart to be 38,829 hectares. Both estimates of tuart extent are valid. The variation occurs due to differences in mapping purpose, the level of detail of vegetation mapping, and the interpretation of remnant vegetation.

See Tuart Atlas Contents.