Stromlo Plantation Forest

Category: Forest Biomes.

Geographic Location: Australia.

Summary: The nearly 100-year-old Stromlo plantation forest was heavily damaged in the widespread brushfires of 2003 and is not slated to be replanted.

The Stromlo Plantation Forest biome was an anthropogenic monocultural ecosystem consisting almost entirely of exotic Monterey pine (Pinus radiata) trees planted on degraded land on the outskirts of the new capital city of Canberra, Australia, in 1915. Canberra was established in a sparsely populated agricultural district—the Limestone Plains—in the first decade of the 20th century. Mount Stromlo, nearby, was the site of the earliest afforestation planting associated with the new capital.

The fortunes of Stromlo Forest waxed and waned in response to changing public policy and periodic bushfires for 90 years. In 2003, a fast-moving and intense bushfire driven by a convection column consumed nearly all of the forest. Today, the legacy of the Stromlo plantation is reflected in a large arboretum that has been established on part of the site; this now includes the National Arboretum Canberra and the Gardens-Mount Stromlo Forest Park. The rest of the property has been earmarked for urban development, recreation, and conservation.

The range of average temperatures in Mount Stromlo Forest Park is 76–79 degrees F (24–26 degrees C) during the summer months of December through February, and 51–54 degrees F (10–12 degrees C) during the winter. Annual rainfall is approximately 38 inches (973 millimeters).

History

Europeans first visited the Limestone Plains district in the 1820s, and pastoral development proceeded quickly. The rapid uptake of land for pasture was facilitated by the dominant pre-European ecosystem, yellow box-Blakely’s red gum (Eucalyptus melliodora-E. blakelyi) grassy woodland. When Europeans arrived in Australia, the ecosystem was dominated by large, widely spaced eucalypts with an understory of grasses and forbs that were palatable for sheep and cattle. Agricultural development largely consisted of displacing the indigenous inhabitants, building homesteads, and expanding the supply of water for the sheep flocks.

By 1911, when the Australian Capital Territory (ACT) was established, the nonindigenous human population was 1,714, while the sheep population was 224,764. The high stocking rates of sheep and feral rabbits, combined with the removal of the native trees for timber and firewood, resulted in a highly degraded landscape. Afforestation was an obvious tool for protecting soil, reducing the dust problems, suppressing the rabbits, and creating a supply of softwood timber for the projected increase in the human population.

To meet the land management issues that were affecting the site of the new capital, the Commonwealth Afforestation Branch was established in 1913 under an energetic officer-in-charge, Thomas Weston. One of Weston’s tasks was to find out which species would grow well in the Canberra region for the functions of timber production, ornament, climate amelioration, and food. Planting on Mount Stromlo proceeded rapidly, probably encouraged by the establishment of an astronomical observatory on the summit in 1911. The building housing the Oddie telescope (the first telescope to be installed at Mount Stromlo) was the first Commonwealth building in Canberra, and the need for night skies clear of dust probably provided the impetus to set the surrounding land aside for forestry.

Flora

The first trees were planted on Mount Stromlo in 1915, and over the following 10 years, more than 20 different species were trialed, including pines (Pinus spp.), poplars (Populus spp.), cedars (Cedrus spp.), cypress (Cupressus spp.), a Babylon willow (Salix babylonica), and a range of Australian natives such as eucalypts, wattles (Acacia spp.), and silky oak (Grevillea robusta). By 1924, more than half the plantation area, 1,307 acres (529 hectares), in the ACT was on Mount Stromlo; this became known as Stromlo Forest.

The trials showed that Monterey pine (Pinus radiata) was the most productive species on the site. Of the 982,200 trees planted there in 1915–25, 932,000 were of this species. At this time, the Pinus radiata seedlings were spaced in a 5.9-foot-by-5.9-foot (1.8-meter-by-1.8-meter) grid. All planting was preceded by rabbit control, site cleanup, and fencing.

Due to the lack of site-preparation machinery, explosives were sometimes used to prepare the ground, but even so, dry seasons in 1918, 1919, and 1921 caused heavy losses that had to be made up in the following years. Despite the setbacks, a 1925 report to Parliament recommended a total pine-forest estate of 20,016 acres (8,100 hectares), which established the broad objectives of forest policy in the ACT. These were commercial wood production, catchment protection, better water quality, prevention of soil erosion, and improvements to amenities.

When Weston retired in 1926, the Afforestation Branch became the Forestry Branch. The site for the Australian School of Forestry (now known as Westbourne Woods) had been selected near his arboretum.

The success of forestry operations at Mount Stromlo led to a gradual expansion of the program into other areas of the ACT. Canberra’s water-supply catchment in the Lower Cotter Valley was planted with pines in an effort to reduce soil erosion, and in the 1930s, worker relief programs planted eroded grazing land. A further large expansion occurred in the 1950s, when government policy called for a total pine-forest estate of 40,031 acres (16,200 hectares). Some of this was achieved by clearing native forest in the mountainous region on the western side of the ACT. In 1967, another government committee recommended that the area of pine forest be maintained at 40,031 acres (16,200 hectares) and that action to initiate a major forest industry be taken.

During the 1970s, silvicultural practices were modernized, with plantations pruned and thinned to produce both saw and peeler logs for plywood. Much of the unthinned plantation, including areas that had self-seeded following major bushfires in the 1950s, was harvested and replanted under the new regime.

Wood from ACT forests was known for its higher density and strength resulting from the relatively slow growth of trees in the dry conditions. The slow growth, however, produced a relatively low internal rate of return. This was partly compensated by the proximity of the wood processors; Stromlo Forest was 4 miles (6 kilometers) from the center of Canberra. It also was close to the area’s population center, and the community was pressing for recreation opportunities that required creative management of the forest. The 1970s ushered in a multiple-use policy for the forest estate and the end of converting native forest to pines to accommodate altered community perceptions of the practice.

Biodiversity

The Stromlo-Canberra region is home to a rich assortment of birds, animals and fish. Among the native bird species are red-rumped parrot, red-browed firetail, white-eared honeyeater, and red wattlebird; among those introduced are the common starling and common myna. The Australian painted snipe and Australasian bittern were added to the ACT endangered species list in 2019. Critically endangered species include the swift parrot and regent honeyeater.

Introduced fish species have pushed out the native ones from most of the ACT rivers; these exotics include carp, brown and rainbow trout, redfin perch, mosquitofish, and dojo loach. Native fish species include the Murray cod and golden perch, two-spined blackfish, trout cod, silver perch, Macquarie perch, and mountain galaxias. The Macquarie perch, silver perch, and trout cod were added to the ACT endangered species list in 2020.

Terrestrial animals native to the area include Gould’s wattled bat and little forest bat. The dingo, extensively persecuted for years, still survives in the ACT and is interbreeding with feral dogs, threatening the genome. The population of the eastern grey kangaroo is robust in the grasslands here, the swamp wallaby is common in the ranges, and common brushtail possum is common in bushland, as well as in urban areas. Koalas do not live naturally in the ACT any more, but likely did so prior to the 1939 bushfires that decimated their principal food source. The brush-tailed rock-wallaby, eastern quoll, smoky mouse, and southern brown bandicoot are endangered.

Environment

In 2003, a large, fast-moving bushfire that had ignited in the Brindabella Mountains to the west of Canberra consumed 24,711 acres (10,000 hectares) of ACT Forests pine plantations, including virtually all of Stromlo Forest, the historic Mount Stromlo Observatory, ACT Forests headquarters, and 500 homes in the nearby suburbs. Following the fire, a review of the forestry operations concluded that the Stromlo plantations should not be replanted, and ACT Forests was absorbed into the ACT Parks and Conservation Service.

A large mountain-bike facility was established on the slopes of Mount Stromlo, and replantings have been mostly of Australian native trees and shrubs. Another part of the former forest was set aside for the International Arboretum, featuring 100 forests composed of rare and significant tree species from Australia and around the world. Much of the rest of Stromlo Forest has been allocated for urban development, and the ACT Fire Management Unit headquarters at Stromlo Depot sits amid the new urban infrastructure. The original ecosystem, yellow box grassy woodland, is listed as nationally threatened, along with several of the species associated with it.

Climate change in the forests poses the threat of increased insect outbreaks and wildfires that could become more widespread and harder to manage. The warmer temperatures could increase the physiological stress on the trees that could augment die-off, made worse by increased drought conditions.

Bibliography

Bartlett, A. G. Community Participation in Restoring Australian Forest Landscapes. Canberra: Australia Department of Agriculture, Fisheries and Forestry, 2010.

McComb, Brenda C. Wildlife Habitat Management: Concepts and Applications in Forestry. Boca Raton, FL: CRC Press, 2007.

Richardson, D. M. The Ecology and Biogeography of Pinus. Cambridge, UK: Cambridge University Press, 2000.

Shea, Syd, Peter Kanowski, Diana Gibbs, Allan Gray, and Ross Smith. ACT Forests Reforestation Business Case. Vantaa, Finland: JP Management Consulting, 2003.

"Threatened Species and Ecological Communities." Environment, Planning and Sustainable Development Directorate, Australian Capital Territory Government, 29 Aug. 2022, www.environment.act.gov.au/nature-conservation/conservation-and-ecological-communities/threatened-species-and-ecological-communities. Accessed 2 Sept. 2022.