Bark Beetles kill Canary Pine trees
Tenerife's pines under threat from Bark Beetles
Tenerife in the Canary Islands has many beautiful pine woods that cover large areas of its mountain ranges but sadly some trees are dying. Although the Canary Pine (Pinus canariensis) is able to withstand and recover from forest fires it is no match for bark beetles.
These tiny beetles from the insect family known as the Scolytinae live, as their name suggests, under the bark of the trees they infest, where their tunnelling does such serious harm to the tree that it can weaken badly and eventually die. The first signs are for the normally dark green pine needles to go brown.
All about Bark Beetles
According to Wikipedia there are as many as 6,000 species of bark beetles in the subfamily Scolytinae and 200 genera. These tiny beetles are considered as highly specialised relatives of the true weevils in the family Curculionidae.
The Mountain Pine Beetle (Dendroctonus ponderosae) is a serious threat to conifer forest trees in North America.
In the UK and Europe the European Elm Bark Beetle (Scolytus multistriatus) is a danger to Elm trees because it carries the Dutch Elm Disease fungus (Ophiostoma) which has destroyed countless specimens of these trees. Britain lost very many majestic old Elms due to this little insect and the fungus it transmits, and this once commonly seen trees has become scarce in many parts of the countryside and parkland.
Some types of bark beetle have formed a symbiotic relationship with fungi of the Ophiostomatales family and these insects are known collectively as "Ambrosia Beetles." This is because they farm the fungi for food and are one of only three classes of insect that practice farming with ants and termites being the other types.
These Ambrosia Beetles infect other trees with the spores they carry of the fungi they have a symbiotic relationship with in order to create fungal gardens they can utilise as food sources. Unfortunately in doing this they can often end up killing previously healthy trees, s happened with the outbreak's of Dutch Elm Disease that devastated the UK's countryside by destroying so many trees there.
Bark beetles feed on both dead and living trees and many species attack weakened trees and then contribute to their decline, resulting ultimately in the death of their hosts. In Tenerife many of the pines that have been attacked were already weak after recovering from forest fires which swept across much of the land in 2007.
The beetles and their larvae feed just under the bark of infected trees where they make tiny tunnels through the wood. These can easily be spotted if the unhealthy bark is broken off and examined.
Bark beetles are attracted to already infected trees and congregate in great numbers which will result in the death of a tree like this.
Sometimes very big and old trees get killed by bark beetles but young trees come under attack too.
A visible warning sign that all is not well is when you can see the clumps of normally green needles turning brown in colour. On trees that are on their way out this is what happens to all of their needles. They fall off and the tree has no way of absorbing the food any longer that is produced by the action of sunlight on the green chlorophyll in its leaves.
It is very worrying to know that bark beetles are attacking and killing Canary Pines on the island of Tenerife and it is to be hoped that the Forestry department here can do something about stopping this.
Bark Beetle Documentary
Mountain Pine Beetle: A Climate Change Catastrophe
Norfolk Island Pines under threat too
The Norfolk Island Pine or Norfolk Pine (Araucaria heterophylla) is also in danger from the attacks of bark beetles. This attractive evergreen tree is commonly planted in parks and gardens around the island.
It produces an almost Christmas-tree shape and is very eye-catching, hence its popularity. Again though, like the Canary Pines, many specimens have sickened and died after turning brown and dropping their foliage. Sadly some fine specimens of this very ornamental tree have died and had to be cut down and removed.
It is to be hoped that an answer is found to stop the deaths of so many Tenerife pine trees in time.
Pine Bark Beetle larvae
Bark beetle links
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