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Hi All, Oct 1, 2008
Contrary to rumors spread by professional Entomologists for
generations, and others who don't know much about trees, I doubt very
much that even one conifer tree has ever been killed by bark beetles.
They move in and finish the job when trees are under stress and these
beetles are able to do so because the resin ducts, normally filled and
under pressure in healthy trees, do not exude appreciable resin when
severed, provided the tree is stressed (higher water tensions, less
photosynthate, less root/soil contact...).
The Annapolis Valley, being the tailpipe of Eastern North America,
has experienced appreciable Spruce and Fir dieback for 15 (perhaps 20)
years. The initial stress here was likely low-level Ozone and acid-rain
(for want of any other likely culprits) but tree death became especially
widespread here during those dry years that also gave the BSLB inroads
in Point Pleasant park. The Task Force of course blamed the BSLB, duh
and we know how that turned out. Those BSLB, that 'attact apparently
healthy trees', didn't move much after the dry spell ended until Juan
gave them a swath of damaged trees along which they could readily spread.
Welcome to the future and I continue to pray for $7.00/ litre
gasoline (it used to be $5.00 but one must allow for inflation) or at
least more use of wind power, .hydrogen and battery-powered vehicles.
The connection between tree health and beetle activity is most
readily seen by cutting a healthy White Pine or Spruce tree during warm
weather (or vigorous Spruce branches 1-2" in diameter and trimming them
to reduce rate of water loss); tree severed from stump being the extreme
case of ill health. Sometimes within hours, and always within days, bark
beetles (Scolytinae) will arrive, soon to be followed by predaceous
Checkered Beetles (Cleridae). For example, on May 7, 2007 I cut a large
crooked White Pine that was good only for short planks, ashes and insect
fodder and ripped a few slabs off; crooked but entirely healthy and free
of insect borings or activity. When I was next out on May 9, there were
four species of Bark Beetle (2 Ips species, Dendroctonus valens and
Hylurgops rugipennis), two of these abundant, and numerous Thanasimus
dubius (Cleridae).
Yt, Dave Webster, Kentville
John Kearney wrote:
>On the Northumberland Shore, the many dead spruce trees seem to result from
>a combination of old age, salt spray, and bark beetles. I have found on my
>property that it is best not to cut down the dead trees. Even in death,
>they provide shelter from wind and salt spray to the living trees behind
>them. Although it may not be aesthetically pleasing visually, the standing
>dead trees help prolong the life of the mature trees while regeneration is
>taking place below.
>
>-----Original Message-----
>From: naturens-owner@chebucto.ns.ca [mailto:naturens-owner@chebucto.ns.ca]
>On Behalf Of Lynn Ellis
>Sent: September 30, 2008 13:39 PM
>To: naturens@chebucto.ns.ca
>Subject: Re: [NatureNS] Re: Dead spruce trees
>
>The dead trees are everywhere and they have been dying on my property
>for sometime. I have been told its a beetle that gets under the bark
>and eats the tree ultimately killing it. I have noticed that there
>are hundreds of dead or dying trees between here in Hfx.
>
>Lynn
>On 30-Sep-08, at 1:28 PM, Roland McCormick wrote:
>
>> Everywhere I go in the Barrington area these days I see
>>dead spruce trees. They are now coming in my own back yard. I had
>>one dead tree removed recently, and was told I would have a half
>>dozen more in a year or two. It seems that it is the old trees
>>that are dying - inspect them and you will find small brown lumps
>>on the bark caused by some kind of beetles. I am wondering how
>>widespread these are in NS, and how serious the problem will become..
>>
>>Roland
>>
>
>
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