Wanted: healthy ashes

Help the SNS researchers save the ash, the tree of life in Nordic mythology and, above that, an important basis for at least 480 other species. Ash dieback has rapidly reduced the number of ashes in the Nordic countries and in Europe.


Green square with black text. Illustration.Researchers are now looking for healthy ashes in sick ash stands – because the key to rescue the ashes is in their genes. There are ashes more resistant to ash dieback than others. They are not many, but they exist.

A sick ash has a sparse crown where the dead leafs has been compensated by a lot of new sprouts in the end of the branches, which gives them a special look. Sometimes you can also find wounds on the branches and stems.

However, in some stands you can see one or a few healthy ashes among the sick ones. Those are the trees that the researchers are interested in, because they most probably has a genetic resistance that could be used to grow new, vital ashes.


So why save the ashes?

Trees and blu sky seen from below. Photo.

Photo: Michelle Cleary

The ash has been a well valued tree in urban environments and the forests of southern Sweden and elsewhere in the Nordic region where the beautiful ash wood has been used for example for furniture. But it is also important for about 480 other species of herbs, lichen, mosses and insects. As many as about 120 of those species are threatened! It is obviously important for the biodiversity to create a healthy ash population.


A European problem

The ashes got sick in Poland and Lithuania in the 1990’s and the fungi is now spread across Europe. The Nordic ashes were first infected in the early 2000’s. Research is going on all over Europe to save the tree species. It is a problem for the ash that the research has not previously been carried out over nation borders – the fungi itself does not care for borders a bit!

– The coordination of the research has not been good between countries, but in the newly funded SNS project (Conservation of resistant ash genotypes to maintain full range of ecosystem services) we get the possibility to exchange knowledge between the countries, coordinate research and share both research results and material, says Lars-Göran Stener at Skogforsk in Sweden.

– It would also be more economically efficient if we could coordinate the research better.


Seedlings in Denmark

Danish seedlings of resistant ash can be available within a few years. There, as in many other European countries, research is partly funded by the state. This is not the case for the ash research in Sweden, despite the fact that the ash is a highly threatened species. There, the research is dependent on private research funds.

In Sweden there are a few clones that are strong and healthy and constitutes a base for a future ash population. They are too few to be used in a seed orchard where improved seed to the forestry is produced. However, they could be vegetatively propagated (cloning) by for instance grafting. This is a too expensive alternative for forestry but a possible way to replace damaged ash trees in the cities.

By networking, meeting and exchanging experiences, knowledge and results, it is possible to take the research forward and advance faster. And for the ashes, it is urgent.

– We have got way too few clones to build a population on, says Lars-Göran Stener.


Emergency call

That is why he and other researchers call for healthy ashes. They hope for the public to report ashes that could be of interest for the researchers.

The researchers want reports of the location of healthy individual ash trees that are surrounded by diseased ashes. Genetic differences among the trees are likely the reason for why some trees in a stand appears to be healthy, while the majority of the trees are severely affected by the disease.

– If a single tree in a garden looks healthy it could as well be because the fungi isn’t present at that spot, says Lars-Göran Stener.



So, if you notice a healthy ash among other, sick looking ashes, please report it to Lars-Göran Stener at Skogforsk: lars-goran.stener@skogforsk.se.

Leave your name and phone number, where you have seen the trees and describe the stand. If possible, leave gps-coordinates for the tree. The researchers will get in touch with you as soon as they get your mail!


Do you know someone interested?

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