[NatureNS] Notice of Meeting on Hemlock Woolly Adelgid

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From: David Simpson <david.sonsimp@gmail.com>
Date: Thu, 1 Mar 2018 08:13:13 -0400
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Pardon my ignorance, but, briefly, what was the red spruce saga?

Thanks,
Dave in Halifax
On 28 Feb 2018 08:10, "John and Nhung" <nhungjohn@eastlink.ca> wrote:

> There=E2=80=99s another point worth discussing:  if and possibly how less=
ons from
> the red spruce saga could/ should be applied (or not!).
>
>
>
> *From:* naturens-owner@chebucto.ns.ca [mailto:naturens-owner@
> chebucto.ns.ca] *On Behalf Of *Nick Hill
> *Sent:* February 27, 2018 3:14 PM
> *To:* naturens@chebucto.ns.ca
> *Subject:* RE: [NatureNS] Notice of Meeting on Hemlock Woolly Adelgid
>
>
>
> I agree, John.
>
> I too am leery about introducing yet another exotic to combat an exotic.
>
> The sanitary approach is also worrisome as that approach leaves no organi=
c
> no food for woodpeckers and doesn't let the tree determine its fate. I ju=
st
> got back from a walk where I showed my sister from UK healthy beech and
> then we found a large slightly chancred beech that had overgrown a
> miserable chancred individual that had died. I had to think about the
> possibility of differential susceptibility and evolution of resistance. W=
e
> need to give the hemlock that chance.
>
> And then there was the American Chestnut and its loss and replacement by
> chestnut oak.
>
>
>
> Yes. We can do more than one thing and that's good. But I may be averse t=
o
> any agency that has the authority because of its name to come and cut out
> my hemlock. They did this with the red spruce with not much ecological
> understanding.
>
> Nick
>
>
>
> On Feb 27, 2018 2:26 PM, "John and Nhung" <nhungjohn@eastlink.ca> wrote:
>
> Good points, and I=E2=80=99d be uncomfortable with some proposed interven=
tions.
> Introduction of any exotic, for instance, has unpredictable consequences.
>
>
>
> I don=E2=80=99t think there=E2=80=99s any necessary conflict between atte=
mpts to preserve
> hemlock and other sustainable forest management initiatives.  For instanc=
e,
> I keep wondering about seed banks, which may or not be a good idea =E2=80=
=A6
>
>
>
> Hope you=E2=80=99re gonna catch some of the sessions, Nick.  The MTRI-org=
anized
> ones are probably more geographically conveniently-located.  You could
> contribute substantively to the discussions!
>
>
>
> *From:* naturens-owner@chebucto.ns.ca [mailto:naturens-owner@
> chebucto.ns.ca] *On Behalf Of *Nick Hill
> *Sent:* February 27, 2018 12:17 PM
> *To:* naturens@chebucto.ns.ca
> *Subject:* Re: [NatureNS] Notice of Meeting on Hemlock Woolly Adelgid
>
>
>
> Hi John and John
>
> I don't doubt that the woolly adelgid will kill hemlock trees and that is
> change and unwelcome.
>
> Let us first put it in a North American context with climate change and
> atmospheric N deposition.
>
> We can research the impact that has occurred where the pest has moved
> through from Virginia through New England.
>
> And then we can look at stand vulnerability factors. We stand to lose
> trees and some stands. The outbreaks will be heterogenous: stands receivi=
ng
> more N in SW Nova could be more affected. Cool ravines should be less
> affected. Stands near the coast may be less affected because there has be=
en
> less temperature change over the past 30 y.
>
>
>
> From what I have read, things were not wholly disastrous. The trees in
> some infected stands were mainly killed whereas hemlocks in other stands
> were less affected and in some, most trees survived. The carbon stays in
> the ecosystem. This is habitat. A new forest takes shape and this normall=
y
> includes in the US where hemlock trees have been killed,  *Betula lenta*
> that we dont get here and *Betula alleghaniensis* (yellow birch) that we
> do.
>
>
>
> We should fight the things we can fight and influence such as
> clearcutting, unnecessary roads, poor land use and wetland loss.
>
> We can do all measure of things: fighting invasives broadly, spraying the
> budworm with bacteria and sprays,  introducing organisms to fight adelgid
> or the sanitary removal of diseased hemlock. Or we can protect forest
> processes by reducing cutting frequency and intensity (this will mean les=
s
> nutrient and organic matter, structure and carbon removal), using
> shelterwood management (maintains shade and moisture and structure),
> protecting by buffers ravines (shade and moisture)  and wetland corridors=
,
> and setting up mature forest corridors (birds, mammals, herbs...and...?)
> throughout the forest. We cant stop this climate change but we can make o=
ur
> forests as healthy as we can. The forests will be dynamic and we can
> protect mature forest processes but not determine what the eventual fores=
t
> will look like.
>
>
>
> Losing some hemlock stands does suck but any reactive response to adelgid
> can be seen in a larger perspective of processes.
>
> Let's fix unsound forestry practices and let the forest take care of
> itself. We would be pleasantly surprised on balance. Less hemlock, more
> yellow birch,white pine, red spruce and in 50 years, our forest may have
> changed again.
>
>
>
> Nick
>
>
>
>
>
> https://etd.ohiolink.edu/ap/10?0::NO:10:P10_ETD_SUBID:76019
>
> a PhD thesis on hemlock riparian forest in Va and WV (K Martin 2012 Ohio
> State)
>
> Hemlock forests exhibit low species richness, and thus have low
> resiliency. In uninvaded forests of Ohio, hemlock dominates the vegetatio=
n,
> although other species are structured by environmental gradients.
> Structural equation modeling indicates hemlock has a negative influence o=
n
> vegetation species richness, light availability and productivity. Thus, a
> likely future HWA arrival will result in a complete reorganization of the=
se
> ecosystems, but impacts will differ across environmental gradients. Data
> from sites impacted by HWA 9-32 years in West Virginia and Virginia
> indicate all hemlock forests will likely be impacted. Although mortality =
is
> initially slowed at higher elevations and on steeper slopes with northerl=
y
> aspects, eventually, the duration of HWA invasion is the most important
> driver of mortality and ecosystem change. As decline progress, hemlock
> remains dominant in sites impacted for decades, although compositions are
> shifting and diverging across overstory hemlock decline classes. Some
> species, including the native evergreen shrub rhododendron (Rhododendron
> maximum) and other evergreen species including red spruce (Picea rubens),
> may be particularly influential during community reorganization.
> Environmental gra