There has been understandable anger about the government’s handling of the Ash tree crisis in the UK, but I wonder if it is partly misdirected. Trying to pull up a biosecurity drawbridge by banning plant imports seems to be at best a Canute-like reaction. We should do what we can, of course, but what we need is a better longer term pre-emptive strategy of prevention. We can at least slow the spread of disease by changing perception about the importance of the provenance of plants and seed and labelling them properly for consumers. This would buy time to formulate a more effective response to a problem which may then never even reach us.
We are much better at blaming each other for environmental disasters than we are at containing them. The size and complexity of these problems dwarfs the resources which government can throw at them. The scale of the tragic story of the American chestnut (Castanea dentate), for example, almost confounds understanding. A blight, probably originating from chestnut trees imported from Asia, spread like wildfire down the East Coast in the first half of the last century and killed up to an estimated 4 billion trees.
Of course plant pathogens and parasites have always spread and over time plant populations often recover from them, but their consequences can be so severe we should do everything we can to lengthen the odds of accidentally importing them ourselves. The Ash tree disease might have been blown here from across the Channel rather than relying on human agency like the American chestnut blight, but it might not. Trees and their diseases travel all around the globe and have done since the Romans started planting reminders of home around their Empire and importing exotic fruit into Italy. Horse Chestnuts, introduced here in the late 16th century from the Balkans, are now quietly bleeding to death in leafy London suburbs from a combination of a canker from the Himalayas and a leaf mining moth from Macedonia. Many pathogens and parasites migrate between species; Ramorum disease, currently killing larch here, is also found in rhododendrons. Even for the Australians, with their natural advantages of geography and population, controlling plant imports is difficult.
Bizarrely for such a common tree, enormous numbers of our native ash are imported into Britain. We want them cheaply and instantly available. Much planting is grant aided, and usually comes with the expectation that trees must be bought immediately and at the lowest price available. This is in keeping with the general attitude consumers have towards buying plants or seed. Unfortunately, as a consequence, plants and seeds have to be sourced from abroard. We need bigger and more profitable nurseries here, producing native trees, wildflowers, fruit trees and hedge plants. How can they be nurtured? Consumers have to be encouraged to think about tree planting as something which gives slow pleasure rather than instant gratification. If they are ordering a large number of plants or volume of seed they could be encouraged to do so a year in advance to give smaller growers a better chance of bidding for the business.
No-one buying plants or seed online or at a garden centre currently knows where they’re from or even, if online, who they’re from. There is a “specialist” site I know selling fruit trees, run by a firm of web designers. Most countries have provenance certification schemes for trees and wildflower seed from local producers, but unless you were a professional you wouldn’t know – or know to ask for a certificate.
When a prospective buyer searches for “native wildflower seeds”, “woodland trees”, or “conservation hedging” they might reasonably expect that the plants and seeds that they find are actually native (like the ones we sell!). The question of what constitutes “native” vexes ecologists all over the world and its answer varies, but however you define it, the “native” plants or seed the online buyer stumbles across are probably not. “Wildflower” seed mixes often even include species from the other side of the world; around the corner from us is a lovely spot which the owner thinks is a traditional English meadow as it’s full of wildflowers. They’re North American wildflowers. Is that a problem? It is if there’s anything invasive or diseased there, or if you’re trying to encourage butterflies, for example, whose larvae typically only eat indigenous plants.
This is where we can usefully educate and regulate. Oblige online resellers and nurseries to label the origin of their plants, in the same way that supermarkets do with food. Educate consumers to value locally produced seeds or plants and pay a decent amount for them. The precarious and unrewarding lot of local growers might then be improved enough for them to earn a decent living.
Globalism and biodiversity are unhappy bedfellows, but consumerism and biodiversity could get along very well. People will always buy native trees or wildflower seeds rather than collect them themselves, so we should make sure they know how to buy the right stuff.