This indicator provides information on the number and distribution of forest-associated species at risk of losing genetic variation across their population. This erosion in genetic variation makes species less able to adapt to environmental change and more vulnerable to extinction. Some local populations with unique gene pools may also risk being swamped by larger populations introduced intentionally, by accident, or by natural processes.
The dominance of a single exotic planted forest species, radiata pine, creates biotic risks, which are exacerbated when it is grown in large-scale monoculture. The risks take two main forms. The first is that pests or diseases that may or may not be present in the native environment become established and run rampant. The second occurs when species are grown outside the climatic or edaphic range of their native environment. For radiata pine, which comes from a winter-rainfall environment but which is grown on summer-moist sites in New Zealand, this increased risk is from fungal diseases such as the foliar pathogen Dothistroma septosporum, which first infected New Zealand planted forests in the early to mid-1960s.
The ability to counter these risks through breeding programmes relies on the preservation of genetic diversity. During the 1980s, forest industry and research organisations established the Radiata Pine Breeding Cooperative to manage the tree breeding and own the genetic resources of radiata pine. This was superseded in 2000 by the Radiata Pine Breeding Company, which now owns and manages the genetic resource, including that of the original landrace populations that underpin the main, elite and production populations used by today’s forest industry.
For researchers, the shift from bulk funding to a more contestable model, in which funding outcomes are heavily influenced by the forest industry, has constrained their ability to investigate issues that are not seen as immediate priorities by the industry. On the regulatory front, continued strengthening of biosecurity requirements is making it more difficult to import new or replacement genetic material. Despite these concerns, the general view in the forest industry is that, with radiata pine now entering its fourth generation of breeding, there remains more than enough genetic diversity for new selections against disease. Similar issues surround other planted forest species, notably Douglas-fir, the eucalypts and the cypresses. Most non-tree exotic forest-associated species are not at risk in this way.
The challenge for both government regulators and industry representatives is to balance the requirement for industry profitability against the need to maintain the genetic diversity of the key forestry species in order to maximise the ability of researchers to respond to future challenges.
Changes to forest ownership and institutional frameworks over recent decades may be placing some of the existing radiata pine gene pool at risk. Similar issues surround other planted forest species, notably Douglas-fir, the eucalypts and the cypresses. Most exotic non-tree forest-associated species are not at risk in this way.
The large-scale shift of planted forests from public to private ownership since the 1980s has resulted in a loss of institutional knowledge of stands covenanted to protect genetic resources. It has also created incentives to prioritise short-term financial returns over issues concerned with the longer-term security of the industry. The change from forestry to more profitable agricultural land uses, notably dairy farming, has also been responsible for the loss of some covenanted stands.