A GROWING PROBLEM

The mountain pine beetle is just oversix millimetres long (about the size of agrain of rice).

But the tiny forest insect has infested huge areas of mature pine around the interior of British Columbia, causing colossal amounts of damage to B.C. forests.

The beetle likes mature pine and mild weather.

Because B.C. has more old pine than ever before, and has had several consecutive mild winters, mountain pine beetle populations have exploded to epidemic levels.

British Columbia’s beetle infestations doubled in size in 2003 over the previous year. About 4.2 million hectares were attacked in 2002 and mapped this year.

Varying degrees of mountain pine beetle attacks occur in all forest regions of the province, with the largest infested area extending from the south Cariboo region north to Fort St. James.

It has been described as the worst-ever insect infestation in a North American forest.

The beetles attack lodgepole pine, ponderosa pine and more rarely, white pine.

Lodgepole pine, the predominant commercial species in the province, accounts for more than half of the growing stock in B.C.’s interior.

About 160 million cubic metres of timber is now affected by the mountain pine beetle.

In October 2003 the province’s chief forester reported that the mountain pine beetle epidemic may significantly reduce interior B.C.’s timber supply in about 15 years or sooner.

It may not be possible to salvage all the beetle-killed trees for traditional uses, making it necessary for stakeholders to explore the potential for innovative and alternative uses.

The damage done by the mountain pine beetle may also add to the risk of wildfire.

Mature pine stands have been killed at such an unprecedented rate that not all the wood can be salvaged, posing a fuel-load threat on the forest floor.

EFFECTS OF THE BEETLE LIFECYCLE

Flights can begin in June, but are generally in July and August, when trees are most vulnerable to infestation due to water deficiency.

A mountain pine beetle infested-tree will go through three colour stages:

Green is the earliest stage. The beetles have infested the tree (from early summer to early fall), but this cannot be detected and mapped from the air.

The pine needles are their normal colour and appear healthy.

Red is the middle stage. The beetles have left the tree after mining the layer between the bark and the wood. This occurs in the year following the initial attack. The pine needles have turned red, an indicator that the tree is dying because the combined impact of the beetles and a fungus they carry has cut the tree off from its supply of water and nutrients.

COLD IS THE BEST CONTROL AGENT

There’s one thing that really stops the beetle dead – freezing temperatures. Sudden cold snaps (-25 degrees C) in the early fall or late spring, or sustained frigid weather (less than -40 degrees C) in the winter can kill populations of beetles, and help end serious outbreaks.

However Mother Nature has not been co-operative the last several years.

Successive hot, dry summers combined with mild winters in much of central B.C. have allowed the beetle to multiply, and even expand its range to areas that were once historically too cold for the insect to survive.

It is impossible for human intervention to halt the beetle epidemic in its tracks at this stage in the infestation. Until the epidemic ends, British Columbia must work together to slow and contain the

spread of the infestation, and lessen the associated threats to the province’s economic well-being.

Grey is the last stage. The beetles are long gone. The tree has

been dead for some time and the needles have fallen away,

leaving the tree looking grey and barren. This typically occurs in

the year following the red stage.

Healthy pine trees can often withstand light attacks by exuding resin to expel invading beetles.

Large, whitish pitch tubes may indicate the tree has repelled a beetle attack.

Smaller, reddish-brown pitch tubes and lots of dust from boring the bark mean the beetle attack has been

successful and the tree will soon die.

Adult beetles also carry a fungus that they deposit into the sapwood. This fungus causes dehydration while inhibiting a tree’s natural defences and stains the wood blue.

However, these bluestreaked logs are just as strong as other pine logs.

Research has proven that beetle-killed wood stained blue by the fungus remains structurally sound and safe for building.

(See Technical data)