Sunday 18 November 2012

What future for Brent's ash trees?

An ash plantation in Fryent Country park earlier today
It won't really be clear until next Spring and Summer how many of the ash trees in Brent have been affected by ash dieback disease. A considerable number have been planted in Fryent Country Park over the years and contribute greatly to the beauty of the woodlands. With their own open canopy they encourage rich growths of small trees, shrubs and plants beneath the trees.

Brent Parks Department told me:

The spread of the disease, knowledge and best practice are in a fast-changing situation.  Obviously we are vulnerable due to the large number of Ash trees in the Country Park and elsewhere in Brent.

There is very little that we can do protect trees if the disease does spread.  The movement of Ash trees is prohibited so we won't be planting any.  Dried timber is thought to not carry the disease and can continue to be used for timber or fuel; and on my reading of the government Order, felled greenwood can also still be moved for these purposes providing it is not from an area where Chalara is present.  The Government has accepted advice that diseased mature trees should not necessarily be removed in woodland.  Experience from continental Europe is that 10-20% of Ash trees are resistant. 

In practical terms the main protection is not to move Ash material from site to site; and certainly not infected material.  If the disease is also air-borne, then there is little that can be done to directly stop movement through the air.  Longer-term, the important of diversifying woodland would be a good policy, though there are some areas of Britain where Ash naturally dominates woodland, and also in secondary woodland.
Brent Parks will be monitoring the health of ash trees in the Country Park and elsewhere in the borough.

Caroline Lucas, Green MP, has expressed concern and called for changes in government policy to deal with the issue on the Guardian Environment website LINK

To stand a chance of safeguarding our trees and plants, the government must respond to calls from the scientific community for far more radical controls on biosecurity.

According to a growing number of tree disease specialists, this should mean using quarantine for other iconic trees such as oak, pine and plane, and banning imports if necessary.

If plants known to be carrying pathogens were quarantined, as they are in Australia for example, we might be able stop at least some diseases spreading and slow down others. If quarantine conditions are not met, then an import ban should be urgently considered.

Furthermore, as set out in an early day motion by Zac Goldsmith which I co-sponsored, we need guarantees from Defra that the forestry authorities will get the resources they need to ensure both a rapid response to other disease outbreaks and improved screening in future.

Finally, ministers should also look again at the forestry grants system, which perversely seems to encourage imports from overseas and perpetuates the great tree trade. In particular, late decisions by the government on the grant agreements mean that UK growers are often left with no time to grow the saplings here, forcing them to source from abroad.

The potential cost of inaction on these issues is incredibly high. With the Woodland Trust warning that ash dieback could wipe out between 70-90% of our ash trees, it's more urgent than ever that the government listens to the warnings and takes the long-term view – recognising that investment in resources now to safeguard our natural heritage is money well spent.

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