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----- Original Message -----
From: "Donna Crossland" <dcrossland@eastlink.ca>
To: <naturens@chebucto.ns.ca>
Sent: Sunday, January 10, 2016 10:43 PM
Subject: RE: [NatureNS] re Red Herring & Forestry
<snip>
I would hazard a guess that the forests I've
> read that are dying all at once are white spruce (hit hard by spruce bark
> beetle). That situation does not speak for the rest.
<snip>
Dear All, Jan 12, 2016
I wish to advance a few words in honor of Roland. I never had the
pleasure of meeting him but based on his advocacy of a working "crap
detector" I felt that he was a genuine naturalist and, if one had to get
lost in the jungle, a desirable companion in such adversity.
So far as I am aware he was the first person on Naturens to use that
term and as you gain experience in the maintenance and use of a Crap
Detector you will be astonished at the pile of 'information' from
authoritative sources that is selected for rejection.
The gospel that White Spruce is "hit hard by spruce bark beetle" is a
good example. It is relevant to ask why they get hit one year and not
previous years or why these three trees are riddled and a nearby one is
fine. If you look at the weather pattern associated with a year of
'infestation' you will usually find an unusually dry period in the previous
or current year and if you consider the setting of the spared tree it will
usually have more elbow room.
And most importantly one should recognize that a tree, whether it be a
White Spruce, Red Spruce, Ash,... is not a constant but a variate which will
be a function of weather, soil... conditions past and present. In general
Foresters and Entomologists do not have a working and exercised knowledge of
Plant Physiology.
It likely helps to have a woodpile in the yard containing Spruce wood
but if you cut a live healthy branch from a healthy Spruce during the
growing season, and bring the branch home so it can be readily checked for
activity, you will usually see Scolytid and Clerid activity within two days
of warm weather.
The general conclusion which I have reached is that 'infestations' of
all insects which feed in bark or wood are triggered by water stress or
damage which leads to water stress. The exact mechanism is not clear but in
conifers it may be related to resin flow. It could be that no eggs are
deposited in healthy trees or that no eggs survive in healthy trees.
If conifer bark is cut with a sharp knife on a warm day when soil water
is ample then there will usually be a copious and rapid flow of thin resin.
If a similar cut is made after a long period of no rainfall then resin flow,
if any, will be very slow and viscous.
Similar consideration apply to Ash which of course lacks resin so in
non-coniferous trees the mechanism may involve turgor pressure when an
attempt is made to deposit an egg in live tissue, turgor pressure when a
larva first enter live tissue...or something more subtle. But cut a healthy
branch off of a healthy Ash in mid May and within a few days (sometimes
hours) there will be incoming flights of a small weevil (Hylesinus
aculeatus); best when warm & calm. Once again it likely helps to have aged
Ash firewood nearby.
In Memory of Roland and his Crap Detector,
Dave Webster, Kentville
> No virus found in this message.
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> Version: 2016.0.7294 / Virus Database: 4489/11377 - Release Date: 01/11/16
>
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