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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.

Mountain Pine Beetle (Dendroctonus ponderosae)

Mountain Pine Beetle (Dendroctonus ponderosae)

Infested pines

Dying pine tree showing brown dead needles

Dying pine tree showing brown dead needles

Dead pine tree

Dead pine tree

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.

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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


Steve Andrews (author) from Tenerife on March 19, 2012:

JazzRoc, thanks for posting! The problem is the scale of it as can be seen in America and Canada where no solution has been found. Yes, woodpeckers and tree-creepers would eat the grubs I expect but how many of these birds have you seen here? This sort of infestation can only create its own demise when all the trees are gone. Imagine that: all the pines gone! Also think about how many wildlife depend on pine forests and what happens when the trees are cut down. Here on Tenerife there are acres of mostly bare soil above Aguamansa where pines have been felled, though I understand the trees there were killed and damaged by winds last year. If it rains it will wash away a lot of that topsoil and if it doesn't it will become dust and will be too dry for them to replant in. Or am I wrong?

JazzRoc on March 16, 2012:

Infestations have always ravaged forests, just as fires do. A successful infestation always creates its own demise, either by starvation or predation.

Maybe these larvae are tasty, and should be harvested?

Alternatively, predators of these beetles should be offered better facilities. Nest boxes for bark-creeping birds, for instance. Control of bird-eating hawks might help. You get the picture. It's Nature, and we should rationally garden it, I believe.

Earth Angel on July 29, 2011:

Thank you dearest TI,

My blessings to you for a wonderful day! Again, GREAT Hub!

Blessings always, Earth Angel

Steve Andrews (author) from Tenerife on July 28, 2011:

Very sorry to hear of your loss, Earth Angel! The fire here didn't affect me personally apart from the distress of seeing what it had done. One thing that inspires me about this island is how people and nature bounce on back despite disasters!

Earth Angel on July 28, 2011:

Dearest TI,

Those kind of destructive events at the hand of man and the resulting devastating losses can scar a soul forever. I lost three beloved dogs in an arson fire decades ago and it still aches beyond belief.

Thank you for sharing this fairly recent and heart-shattering event. I am so sorry you and others had to go through it.

Blessings, Earth Angel

Steve Andrews (author) from Tenerife on July 28, 2011:

They never caught the arsonist either here although the same thing happened on Gran Canaria and the man responsible was arrested. He was a former forest ranger who had lost his job and was seeking revenge so he set fire to the island's forests! Many pets and farm animals burned to death because they were left behind when people evacuated fast as the fires swept across the islands. Some families lost all their possessions and their homes.

Earth Angel on July 27, 2011:

Auuuuuuuugggggggghhhhhhhhhhh, TI,

That is human "intervention" at its worst! Soooooooo sorry that happened to everyone who did not deserve such fire! And to the innocent animals!

Blessings to you in TI! EarthAngel!

Steve Andrews (author) from Tenerife on July 27, 2011:

Human intervention here was some insane arsonist set fire to the forests in 2007 and lots of people had to be evacuated, many animals died, homes were destroyed and large areas of land ruined! This obviously weakened trees and killed some. The bark beetle problem seems to have happened since the fires.

Earth Angel on July 27, 2011:

Dearest Lady Guinevere,

You are so right! Mother Nature always has a better plan!

And some of the little critters come into areas they have not been before because as people we travel more! Look at what has happened with the bed bug epidemic because the little critters travel unsuspectingly on people's luggage!

Back when fruit flies were causing so much damage to California crops, no person/car etc. was allowed in or out of the state with any produce of any kind! All produce leaving and entering on big 18-wheelers has to be treated first with accompanying documentation!

Killer bees are moving from the South into the United States to places they have never been before as well!

You are so right, Lady Guinevere! Mother Nature always has a better plan than we humans do!

Blessings always, Earth Angel!

Debra Allen from West By God on July 27, 2011:

Earth Angel, there were some things about trying to prevent that natural cycle of fire and other things that nature does for herself running amuk on FB. I tried to squelch those fires because Mother Nature knows what she is doing to her planet. Now I don't know why we have all these short needled pines dying around here, but someone told me a couple of years ago that these Pine borers have only come here in the last 5 years.

Trees that have died also serves a purpose for the land, which we may not see or understand. Taking some of the dead trees out I would surmise would be a good thing--for humans, but is it good for the eco system there? Something to consider anf think about. Maybe Mother Nature has a plan.

Earth Angel on July 27, 2011:

Good Morning Mr. TI,

Usually, when Mother Nature gets out of alignment, there is a human element involved somewhere in the chain of events!

In Lake Tahoe there were mass studies of the mass devastation! The Tahoe Basin is like a large beautiful sapphire blue oval bowl; but what is poured into it has little way of getting out!

The original thought was that the beetle infestation/devastation was just a natural cycle! That turned out not to be true.

Then the thought was too much salt and later sand in winter road clearing of snow in winter! That had a bigger negative affect on water quality than the beetle!

Then the thought was with so much population expansion and building, there were too many chemicals (especially highly fertilized lawns) and the beetles were getting stronger, resistant to treatments! That turned out to be partially true.

As it turned out, the beetle devastation was caused in Lake Tahoe by "not enough fire" over the years! Due to increase in population, most fires were quickly extinguished!

Billions of dollars had poured into lake front and mountain homes! Plus shopping and tourism! Along with hotels and casinos on the Nevada side! A major fire was not in the financial game plan!

But major fire is part of Mother Nature's way and exactly what had helped keep Lake Tahoe so healthy for centuries! Before being so highly populated, lightening would strike, fires would rage killing off weak trees and underbrush making room for healthier trees to breathe!

Looking at photos of Lake Tahoe between 1900-1920 there are 90% fewer trees than there are today! It wasn't due to logging, it was due to the natural cycle of fire! And us "humans" in our infinite "wisdom" found ways to suppress the semi-annual wild fire! Ten times more trees, many unhealthy, became hosts to the beetle!

Lake Tahoe has a policy of "controlled burns" which Rangers set intentionally in 30-60 acre areas! It helps a little but the resources it takes with Rangers, Firefighters, Fire Fighting Equipment, being timed with high humidity and low tourist season, makes the process less than effective!

The sad thing about the beetle-ravaged trees is that they cannot even be harvested for wood! The trees are a complete loss and just rot! Causing of course, more fire danger! And each one must be cut up and hauled off! Millions of trees!

I don't know about Tenerife, but fire actually helps the trees in Lake Tahoe! Not the scathing-to-the-ground inferno-type, but Mother Nature's fire of cleansing! Park of the bark is burned away allowing the tree to breathe and drink in more natural rain water! The fire opens pine cones allowing seeds to scatter and propagate! Pests and fungi and dead wood become natural fertilizer!

Ask around! Are the trees infected with the beetle native to TI?? When was the last major wild fire for cleansing? I imagine "us humans" had our hand in the current problem somewhere along the line!

Sorry to be such a long-winded naturalist this morning!

Blessings to Mother Nature! And to you two! Earth Angel!

Steve Andrews (author) from Tenerife on July 27, 2011:

Thank you for your posts, Lady Guinevere and Earth Angel! I know it has given me a lot to think about! It is part of nature destroying another part of nature we think is beautiful but why is the problem getting so bad? Here it can be blamed on fire damage and drought that weakened the trees.

Earth Angel on July 25, 2011:

Blessings to you TI!

Same thing happened in Lake Tahoe; awful devastation!

Thank you for sharing this! Blessings always, Earth Angel!

Debra Allen from West By God on July 25, 2011:

Hmmm many of our short needle pines are dying right in front of us here in the Eastern Mid-Atlantic states. I have had to cut two very large pines down. They seem to die from the center out. It is a weird scene when one year one half of the tree turns brown and the next year the other half turns brown and dies. So far they have not bothered the long needled Whit Pine. I truly hope whatever it is doesn't. I was told it was some sort of Pine Borer, but it could be this beetle you wrote of. It's kind of sad to watch. Is there any natural (pesticide FREE) way to handle this that you know of?

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