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=20
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 less 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 our forests as healthy as we can. The =
forests will be dynamic and we can protect mature forest processes but =
not determine what the eventual forest will look like.
=20
Losing some hemlock stands does suck but any reactive response to =
adelgid can be seen in a larger perspective of processes.=20
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.
=20
Nick
=20
=20
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 =
vegetation, although other species are structured by environmental =
gradients. Structural equation modeling indicates hemlock has a negative =
influence on vegetation species richness, light availability and =
productivity. Thus, a likely future HWA arrival will result in a =
complete reorganization of these 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 northerly 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 =
gradients, including elevation and soil characteristics, are also =
important ecologial drivers. Among overstory hemlock decline categories, =
resource availability and nutrient cycling are accelerating, but this =
varies with environmental context. =20
=20
On Tue, Feb 27, 2018 at 10:18 AM, John Kearney =
<john.kearney@ns.sympatico.ca> wrote:
Our hemlock trees are in serious trouble. The culprit is an aphid =
relative, the hemlock woolly adelgid, and currently, southwest Nova =
Scotia is the most at threat.
Find out more at 7:00 P.M. Tuesday, March 13. The Tusket River =
Environmental Protection Association (TREPA) will be sponsoring a talk =
by Ron Neville, Plant Health Survey Biologist of the Canadian Food =
Inspection Agency, at the Yarmouth County Museum and Archives, 22 =
Collins Street, Yarmouth =
<https://maps.google.com/?q=3D22+Collins+Street,+Yarmouth&entry=3Dgmail&s=
ource=3Dg> . All welcome.
Questions? Contact John Sollows at 742-2802.
=20
--=20
Dr. N.M.Hill
Fern Hill Institute of Plant Conservation
424 Bentley Road, Berwick, NS, B0P 1E0
phone 902-698-0416
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vlink=3Dpurple><div class=3DWordSection1><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Good points, and I=E2=80=99d be uncomfortable with some proposed =
interventions.=C2=A0 Introduction of any exotic, for instance, has =
unpredictable consequences.<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>I don=E2=80=99t think there=E2=80=99s any necessary conflict between =
attempts to preserve hemlock and other sustainable forest management =
initiatives.=C2=A0 For instance, I keep wondering about seed banks, =
which may or not be a good idea =E2=80=A6<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Hope you=E2=80=99re gonna catch some of the sessions, Nick.=C2=A0 The =
MTRI-organized ones are probably more geographically =
conveniently-located.=C2=A0 You could contribute substantively to the =
discussions!<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><b><span =
lang=3DEN-US =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span>=
</b><span lang=3DEN-US =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'> =
naturens-owner@chebucto.ns.ca [mailto:naturens-owner@chebucto.ns.ca] =
<b>On Behalf Of </b>Nick Hill<br><b>Sent:</b> February 27, 2018 12:17 =
PM<br><b>To:</b> naturens@chebucto.ns.ca<br><b>Subject:</b> Re: =
[NatureNS] Notice of Meeting on Hemlock Woolly =
Adelgid<o:p></o:p></span></p><p =
class=3DMsoNormal><o:p> </o:p></p><div><div><p class=3DMsoNormal>Hi =
John and John<o:p></o:p></p></div><div><p class=3DMsoNormal>I don't =
doubt that the woolly adelgid will kill hemlock trees and that is change =
and unwelcome.<o:p></o:p></p></div><div><p class=3DMsoNormal>Let us =
first put it in a North American context with climate change and =
atmospheric N deposition.<o:p></o:p></p></div><div><p =
class=3DMsoNormal>We can research the impact that has occurred where the =
pest has moved through from Virginia through New =
England.<o:p></o:p></p></div><div><p class=3DMsoNormal>And then we can =
look at stand vulnerability factors. We stand to lose trees and some =
stands. The outbreaks will be heterogenous: stands receiving 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 been less =
temperature change over the past 30 y. <o:p></o:p></p></div><div><p =
class=3DMsoNormal><o:p> </o:p></p></div><div><p =
class=3DMsoNormal>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 normally includes in the US where hemlock =
trees have been killed, <i>Betula lenta</i> that we dont get =
here and <i>Betula alleghaniensis</i> (yellow birch) that we =
do. <o:p></o:p></p></div><div><p =
class=3DMsoNormal><o:p> </o:p></p></div><div><p =
class=3DMsoNormal>We should fight the things we can fight and influence =
such as clearcutting, unnecessary roads, poor land use and wetland =
loss.<o:p></o:p></p></div><div><p class=3DMsoNormal>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 less =
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 our forests as healthy as we can. The forests will be =
dynamic and we can protect mature forest processes but not determine =
what the eventual forest will look like.<o:p></o:p></p></div><div><p =
class=3DMsoNormal><o:p> </o:p></p></div><div><p =
class=3DMsoNormal>Losing some hemlock stands does suck but any reactive =
response to adelgid can be seen in a larger perspective of =
processes. <o:p></o:p></p></div><div><p class=3DMsoNormal>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.<o:p></o:p></p></div><div><p =
class=3DMsoNormal><o:p> </o:p></p></div><div><p =
class=3DMsoNormal>Nick<o:p></o:p></p></div><div><p =
class=3DMsoNormal><o:p> </o:p></p></div><div><p =
class=3DMsoNormal><o:p> </o:p></p></div><div><p =
class=3DMsoNormal><a =
href=3D"https://etd.ohiolink.edu/ap/10?0::NO:10:P10_ETD_SUBID:76019">http=
s://etd.ohiolink.edu/ap/10?0::NO:10:P10_ETD_SUBID:76019</a><o:p></o:p></p=
></div><div><p class=3DMsoNormal>a PhD thesis on hemlock riparian forest =
in Va and WV (K Martin 2012 Ohio State)<o:p></o:p></p></div><div><p =
class=3DMsoNormal><span =
style=3D'font-size:9.0pt;font-family:"Helvetica","sans-serif";color:#4040=
40;background:white'>Hemlock forests exhibit low species richness, and =
thus have low resiliency. In uninvaded forests of Ohio, hemlock =
dominates the vegetation, although other species are structured by =
environmental gradients. Structural equation modeling indicates hemlock =
has a negative influence on vegetation species richness, light =
availability and productivity. Thus, a likely future HWA arrival will =
result in a complete reorganization of these 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 northerly 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 gradients, including elevation and soil =
characteristics, are also important ecologial drivers. Among overstory =
hemlock decline categories, resource availability and nutrient cycling =
are accelerating, but this varies with environmental =
context. </span> <o:p></o:p></p></div></div><div><p =
class=3DMsoNormal><o:p> </o:p></p><div><p class=3DMsoNormal>On Tue, =
Feb 27, 2018 at 10:18 AM, John Kearney <<a =
href=3D"mailto:john.kearney@ns.sympatico.ca" =
target=3D"_blank">john.kearney@ns.sympatico.ca</a>> =
wrote:<o:p></o:p></p><div><div><p class=3DMsoNormal =
style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Our hemlock =
trees are in serious trouble. The culprit is an aphid relative, =
the hemlock woolly adelgid, and currently, southwest Nova Scotia is the =
most at threat.<o:p></o:p></p><p class=3DMsoNormal =
style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Find out =
more at 7:00 P.M. Tuesday, March 13. The Tusket River =
Environmental Protection Association (TREPA) will be sponsoring a talk =
by Ron Neville, Plant Health Survey Biologist of the Canadian Food =
Inspection Agency, at the Yarmouth County Museum and Archives, <a =
href=3D"https://maps.google.com/?q=3D22+Collins+Street,+Yarmouth&entr=
y=3Dgmail&source=3Dg">22 Collins Street, Yarmouth</a>. All =
welcome.<o:p></o:p></p><p class=3DMsoNormal =
style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Questions?&n=
bsp; Contact John Sollows at =
742-2802.<o:p></o:p></p></div></div></div><p class=3DMsoNormal><br><br =
clear=3Dall><o:p></o:p></p><div><p =
class=3DMsoNormal><o:p> </o:p></p></div><p class=3DMsoNormal>-- =
<o:p></o:p></p><div><p class=3DMsoNormal>Dr. N.M.Hill<br>Fern Hill =
Institute of Plant Conservation<br>424 Bentley Road, Berwick, NS, B0P =
1E0<br><br>phone =
902-698-0416<o:p></o:p></p></div></div></div></body></html>
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