For the first time, two new forms of harmful fungal attacks have been found on the contorta pine in Sweden. A damaging fungus that had previously never been found on the contorta has caused damage in a stock in Gävleborg, at the same time as another previously common fungus now suddenly seems to be causing damage. Source: Timberbiz
The contorta pine is found on 5% of the country’s forest area.
“With the help of careful investigations by SLU, we can now unfortunately state that we have new forms of fungal attack that attack and slow down growth on the contorta. We need more knowledge, but of course itis worrying because we need vital and healthy forests,” said Nils Frank, forest consultant at the Norwegian Forestry Agency’s district in Gävleborg where the attack was discovered.
Contorta pine (Pinus contorta) is a North American tree species that has been introduced to Sweden in recent decades, mainly because it grows faster than regular pine.
Earlier this year, the Forestry Agency received information about damage to an office stock north of Hudiksvall near Gnarp.
According to a recent report from SLU, which analyzed the attacks, it appears that the fungus Diplodia was present on some of the damaged trees.
These are the fi rst confirmed attacks of Diplodia in Sweden.
The disease affects the tree’s growth and causes damage that prevents the trees from developing high-quality timber.
Since 2012, Diplodia has been found in scattered places in the country.
In 2017, damage by Diplodia was found on young pine stands in several locations, and the fungal disease was then considered to be established in Sweden.
Now the disease is also present on the contorta.
How extensive this is and the consequences of the findings is something that needs to be studied more closely.
In addition, the examination of the damage to the stand outside Hudiksvall shows that the fungus Sydowia was also abundant on the trees.
It is a fungus that is common, but which is now also found to be able to cause damage to Contortan.
“It is serious that the trees seem to be damaged by Sydowian because it is so common in our forests. Whether it alone causes the damage or contributes, we don’t know yet,” Mr Frank said.
The Norwegian Forestry Agency is disseminating the information to forestry and other actors and urges forest owners to regularly review their forest but also to have as varied a forest with the right tree species on the right land as possible (adapted to location) to increase resilience.
