The environmental problems challenging most industrial economies concern the detritus of their industrial processes; i.e. pollution. Paradoxically, in Australia, one of the most urbanised societies in the world, the most serious environmental issues are those relating to non-urban land management. Pest plants, feral animals, inappropriate cultivation, and disruption of hydrological systems have wrought profound changes to our landscape.
However, whilst acknowledging the oversimplification, few people would take issue with the contention that excessive clearing of native vegetation has been the single most significant cause of land degradation and biodiversity loss in this country.
There is also broad agreement that revegetating a significant percentage of our landscape is urgently and vitally important for the maintenance of both economic and ecological productivity. The awareness of this need is not new, and efforts have been made in the past to encourage landholders to revegetate, but with very limited success. The task is enormous and the benefits too nebulous to entice financially stressed farmers to make such an investment, for the purpose of taking land out of production.
If farmers do revegetate some of their land, they then have to expend resources to manage and maintain that land, which increases fire risk and provides habitat for pests as well as native animals, some of which can be pests as well. The incentives to revegetate need to be more tangible.
The largely urban environmental movement finds it difficult to grasp these realities, but must finally understand that the most essential factor in maintaining and enhancing our landscape values is an economically viable rural population. That population is as endangered as many of our native creatures and if these communities die, who is going to do the actual work of caring for our country? It is easy being green when someone else is footing the bill.
Farm forestry is an obvious way of increasing those incentives, by providing landholders with a means of offsetting the costs of returning deep-rooted perennial native plants to the landscape. Of course, the ecological values of plantations are inferior to the diversity of restorative plantings, but the extent of that inferiority can be minimized with creative design and management. A substantial and growing body of research strongly indicates that proximity to remnant vegetation and water, breadth of plantings, extent of “edge” and connectivity between otherwise isolated remnant vegetation, can create dramatic increases in ecological value. * If this is combined with management regimes that approximate the structure, if not the species diversity, of natural woodland or forest, the plantation becomes even more congenial to wildlife.
The imperatives for carbon sequestration demanded by the current climatic crisis have added a whole new dimension to the arguments for promoting farm forestry.
Economically, if 10% of every farm is set aside for forestry, graziers in particular, could potentially offset their green house emissions. If they planted 30% as envisaged by NRM policy, there is the potential to be able to enhance their farm incomes from both the value of forest products and the earning of carbon credits.
From an environmental perspective, farm forestry has far greater potential for on- going carbon sequestration than permanent plantings, with less risk of fire negating everyone’s efforts. ** There can be little doubt that global heating poses the most serious threat to our biodiversity. If we decline to do what is necessary to reduce atmospheric carbon dioxide, all other efforts to preserve the remnants of our natural heritage will prove to be no more than sad platitudes.
The vision then, is for a mosaic of farm scale plantations, reflecting a diversity of species, design, products and management regimes that specifically embrace the goals of maximising ecological values, carbon sequestration, rural employment and farm incomes. These goals are intrinsically linked. The failure of one will fail them all.
Indigenous Biodiversity Conservation and Plantation Forestry: Options for the future.
David A Norton, School of Forestry, University of Canterbury NZ. 1998
Our goals in plantation forests should be to integrate production and protection in the same landscape (as advocated by the Resource Management Act 1991) rather than replacing one with the other. A review of indigenous biodiversity in New Zealand’s plantation forests shows that many indigenous plants and animals occur in exotic plantations, with the number of species being dependent on plantation age, proximity to indigenous remnants and a variety of site factors (slope, aspect, etc). Plantation forests contribute to the conservation of indigenous biodiversity through: (i) providing habitat for indigenous species; (ii) buffering indigenous forest remnants; and (iii) improving connectivity between remnants.
Options for enhancing indigenous biodiversity conservation in plantation forests include: (i) retention of indigenous forest; (ii) establishing a greater diversity of planted species; (iii) planting a diversity of tree species along streams and roads to provide additional habitat for indigenous animals; and (iv) modifying silvicultural practices within plantations. It is suggested that through the use of spatial modelling, optimisation of the arrangement of different aged compartments, and different plantation species, will maximise both timber production and indigenous biodiversity within a forest thus allowing full integration of these two activities without the loss of production values.
Faunal use of bluegum (Eucalyptus globulus) plantations in southwestern Australia
R. Hobbs1,*, P.C. Catling2, l.C. Wombey2, M. Clayton2, L. Atkins3 and A. Reid2 2003
We conclude that plantations provide some value in terms of habitat for some species, including some of conservation concern, but that this value is limited by the lack of habitat complexity in the intensively-managed plantations.
Eucalypt plantings on farms: Use by insectivorous bats in south-eastern Australia
Bradley s. Law*, Mark Chidel Science and Research, Department of Primary Industries. 2006
Bats were generally insensitive to the effects of patch size and shape as well as the amount of remnant vegetation in the landscape. A negative relationship with understorey cover (including eucalypts if <5 m high) was the most consistent predictor of total activity and species richness. The avoidance of clutter by many species of bats suggests that efforts to restore woodland communities should use lower stem densities.
Fauna conservation in Australian plantation forests
D.H. Lindenmayer R.J. Hobbs. Centre for Resource and Environmental Studies, The Australian National University 2003.
Our review showed that almost all research undertaken in Australian plantations, both in conifers and eucalypts, highlighted the importance of landscape heterogeneity and stand structural complexity for fauna conservation. At the landscape level, patches of retained native vegetation, strips of riparian vegetation, dams, open and clearing areas can significantly increase the number of native species that occur within plantations. Some species that occur in these areas can also use adjacent planted areas, a result common to conifer and eucalypt plantations. The spatial juxtaposition of stands of varying ages throughout plantation landscapes also can contribute to the maintenance of some populations of native taxa. At the stand level, structural complexity is also important for fauna with many species responding positively to the presence of native understorey plants, the presence of windrowed logs, and logging slash left on the forest floor.
The management of plantations to promote landscape heterogeneity and stand structural complexity will, in many cases, involve trade-offs that will influence wood and pulp production. The extent to which this occurs will be dependent on the objectives of plantation management and how far they extend toward the complex plantation forestry model to incorporate social and environmental values in addition to wood and pulp production.
Eucalypt plantations as habitat for birds on previously cleared farmland in south-eastern Australia
Richard H. Loyn*, Edward G. McNabb, Phoebe Macak, Philippa Noble 2007
Mean abundance of forest and woodland birds was higher in eucalypt plantations than cleared farmland, and marginally lower than in native forest. Patterns differed between bird guilds. For example, insectivores that forage in the canopy and tall shrub layers were at least as common in plantations as in native forest, with birds in the latter group using young eucalypts as if they were tall shrubs. Birds that forage from open ground among trees were more common in plantations than native forest, and may benefit substantially from the new habitat fortuitously provided for them. This group includes several species that have declined in natural woodland habitats. Nectarivores, carnivores and birds that forage among low shrubs were less common in plantations than in native forest. Insectivores that forage from eucalypt bark made little use of plantations. Different approaches to plantation design and management would be needed to cater for groups such as these. Specific measures include planting of rough-barked eucalypts in addition to smoothbarked species, and provision of artificial hollows. Retention of existing remnants of native forest (e.g. old trees and forest patches) is a priority, to supply habitat elements that would otherwise be missing for long periods.
**The “Kyoto Protocol” was deficient in several respects, one of which was the failure to recognise forestry products as a continuing mode of carbon sequestration. Furniture, buildings, bio-fuel and even paper dumped in landfill; continue to lock up carbon for decades or centuries. This reality is widely accepted and is expected to receive formal recognition in the near future.
Given that any form of mature vegetation is only carbon neutral and is constantly at risk of releasing its stored carbon if burnt, the rotation harvesting of plantation forests provides on-going sequestration. High growth rates, removal of timber, replanting, and reduced fire risk are factors that recommend commercial forestry as the most effective land use for sequestering carbon.