Dunrossil Drive includes a significant landscape of heritage value that marks the approach to Government House. Charles Weston devised and planted the grand avenue with a row of elm trees either side of the roadway with pine trees beyond. The elm trees were planted as early as 1918, and the pine trees were planted in 1927-28. Eighty years later, the majority of the pine trees were dead or dying, resulting in weakened or falling trees and branches. This area is popular with local residents and the condition of the pines was creating a public safety risk.
The pine trees were removed in two stages in 2013 and 2015/16, followed by replanting 12-18 months after each removal stage. The central avenue of elm trees has been strengthened with evergreen oaks (Quercus englemannii) to enhance the year-round avenue effect, and the dense planting of Pinus radiata has been replaced with a more open planting of Pinus canariensis. The new planting creates a more open parkland setting, better meeting the needs of local residents, improving maintenance standards and better accommodating nearby events.
Anzac Parade was reconfigured and replanted as a memorial avenue in 1965. The Parade was included on the National Heritage List in 2006, along with the Australian War Memorial. It is also a prominent landscape feature of the Parliament House Vista that extends from behind Old Parliament House to the Australian War Memorial, and lined on both sides by Eucalyptus bicostata. Commonly known as blue gum, this species occurs naturally near Canberra at Burrinjuck. According to Pryor and Banks (1991), it prefers more rain than what is usual for Canberra, and suffers severely from drought on sites that are dry or where the soil is shallow. The tree has a life span of approximately 80-100 years in Canberra.
The NCA is currently maintaining the mature treescape by removing individual trees as they fail and replanting in accordance with the original 3-row design. The long-term effect is that while the overall treescape and canopy will be maintained, the tree groupings will consist of plantings of different ages.
The NCA is proposing to replace the Lombardy Poplars (Populus nigra ‘Italica’) in the National Library of Australia (NLA) Forecourt due to their declining condition. The Heritage Assessment of the NLA Forecourt, including the trees, recommended the replacement of the poplars with the same species. The NCA, however, has been unable to obtain ACT Government permission to propagate or import Lombardy Poplars for this project as they are now a prohibited species under the Pest Plants and Animals Act 2005 (ACT). The NCA is considering alternative replacement species and heritage advice. This project highlights changing attitudes to plant species and environmental conditions, and the need for the NCA to consider alternative species while retaining the cultural significance and aesthetic qualities of particular areas.
The 1.2 hectare stand of pine trees at Stirling Park (approximately 40 years old), is in decline and the NCA has already felled 48 dead trees that posed a risk to the public to make them safe. The Stirling Ridge woodland is managed to protect the ecological values of the site. The long-term safety of the site and ecological integrity of the adjacent Stirling Ridge requires the removal of all the pines. As with the approach to Dunrossil Drive, it is proposed to remove all of the pine trees, process the material on-site and reuse it on the National Estate to enhance the health and presentation of areas requiring improvement. It is proposed that the pine trees be replaced with indigenous tree and shrub, forb and grass species to extend the Box Gum Grassland of Stirling Ridge.