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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. 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 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. 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=22+Collins+Street,+Yarmouth&entry=gmail&source=g>. > All welcome. > > Questions? Contact John Sollows at 742-2802. > -- Dr. N.M.Hill Fern Hill Institute of Plant Conservation 424 Bentley Road, Berwick, NS, B0P 1E0 phone 902-698-0416 --f403045e32809b031f056633f320 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div class=3D"gmail_default">Hi John and John</div><div cl= ass=3D"gmail_default">I don't doubt that the woolly adelgid will kill h= emlock trees and that is change and unwelcome.</div><div class=3D"gmail_def= ault">Let us first put it in a North American context with climate change a= nd atmospheric N deposition.</div><div class=3D"gmail_default">We can resea= rch the impact that has occurred where the pest has moved through from Virg= inia through New England.</div><div class=3D"gmail_default">And then we can= look at stand vulnerability factors. We stand to lose trees and some stand= s. The outbreaks will be heterogenous: stands receiving more N in SW Nova c= ould be more affected. Cool ravines should be less affected. Stands near th= e coast may be less affected because there has been less temperature change= over the past 30 y.=C2=A0</div><div class=3D"gmail_default"><br></div><div= class=3D"gmail_default">From what I have read, things were not wholly disa= strous. The trees in some infected stands were mainly killed whereas hemloc= ks 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 a= nd this normally includes in the US where hemlock trees have been killed,= =C2=A0=C2=A0<i>Betula lenta</i> that we dont get here and <i>Betula allegha= niensis</i> (yellow birch) that we do.=C2=A0</div><div class=3D"gmail_defau= lt"><br></div><div class=3D"gmail_default">We should fight the things we ca= n fight and influence such as clearcutting, unnecessary roads, poor land us= e and wetland loss.</div><div class=3D"gmail_default">We can do all measure= of things: fighting invasives broadly, spraying the budworm with bacteria = and sprays,=C2=A0 introducing organisms to fight adelgid or the sanitary re= moval of diseased hemlock. Or we can protect forest processes by reducing c= utting frequency and intensity (this will mean less nutrient and organic ma= tter, structure and carbon removal), using shelterwood management (maintain= s shade and moisture and structure), protecting by buffers ravines (shade a= nd moisture)=C2=A0 and wetland corridors, and setting up mature forest corr= idors (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.</div><div class=3D"gmail= _default"><br></div><div class=3D"gmail_default">Losing some hemlock stands= does suck but any reactive response to adelgid can be seen in a larger per= spective of processes.=C2=A0</div><div class=3D"gmail_default">Let's fi= x unsound forestry practices and let the forest take care of itself. We wou= ld be pleasantly surprised on balance. Less hemlock, more yellow birch,whit= e pine, red spruce and in 50 years, our forest may have changed again.</div= ><div class=3D"gmail_default"><br></div><div class=3D"gmail_default">Nick</= div><div class=3D"gmail_default"><br></div><div class=3D"gmail_default"><br= ></div><div class=3D"gmail_default"><a href=3D"https://etd.ohiolink.edu/ap/= 10?0::NO:10:P10_ETD_SUBID:76019">https://etd.ohiolink.edu/ap/10?0::NO:10:P1= 0_ETD_SUBID:76019</a><br></div><div class=3D"gmail_default">a PhD thesis on= hemlock riparian forest in Va and WV (K Martin 2012 Ohio State)</div><div = class=3D"gmail_default"> <span style=3D"color:rgb(64,64,64);font-family:"Helvetica Neue",H= elvetica,Arial,sans-serif;font-size:12px;font-style:normal;font-variant-lig= atures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:norma= l;text-align:start;text-indent:0px;text-transform:none;white-space:normal;w= ord-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:ini= tial;text-decoration-color:initial;float:none;display:inline">Hemlock fores= ts 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 ind= icates hemlock has a negative influence on vegetation species richness, lig= ht availability and productivity. Thus, a likely future HWA arrival will re= sult in a complete reorganization of these ecosystems, but impacts will dif= fer across environmental gradients. Data from sites impacted by HWA 9-32 ye= ars in West Virginia and Virginia indicate all hemlock forests will likely = be impacted. Although mortality is initially slowed at higher elevations an= d on steeper slopes with northerly aspects, eventually, the duration of HWA= invasion is the most important driver of mortality and ecosystem change. A= s 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 rhodode= ndron (Rhododendron maximum) and other evergreen species including red spru= ce (Picea rubens), may be particularly influential during community reorgan= ization. Environmental gradients, including elevation and soil characterist= ics, are also important ecologial drivers. Among overstory hemlock decline = categories, resource availability and nutrient cycling are accelerating, bu= t this varies with environmental context.<span>=C2=A0</span></span> <br></div></div><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">O= n Tue, Feb 27, 2018 at 10:18 AM, John Kearney <span dir=3D"ltr"><<a href= =3D"mailto:john.kearney@ns.sympatico.ca" target=3D"_blank">john.kearney@ns.= sympatico.ca</a>></span> wrote:<br><blockquote class=3D"gmail_quote" sty= le=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div l= ang=3D"EN-CA" link=3D"blue" vlink=3D"purple"><div class=3D"m_-3361472583328= 459851WordSection1"><p class=3D"MsoNormal">Our hemlock trees are in serious= trouble.=C2=A0 The culprit is an aphid relative, the hemlock woolly adelgi= d, and currently, southwest Nova Scotia is the most at threat.<span style= =3D"font-family:"Calibri",sans-serif"><u></u><u></u></span></p><p= class=3D"MsoNormal">Find out more at 7:00 P.M. Tuesday, March 13.=C2=A0 Th= e Tusket River Environmental Protection Association (TREPA) will be sponsor= ing a talk by Ron Neville, Plant Health Survey Biologist of the Canadian Fo= od Inspection Agency, at the Yarmouth County Museum and Archives, <a href= =3D"https://maps.google.com/?q=3D22+Collins+Street,+Yarmouth&entry=3Dgm= ail&source=3Dg">22 Collins Street, Yarmouth</a>.=C2=A0 All welcome.<u><= /u><u></u></p><p class=3D"MsoNormal">Questions?=C2=A0 Contact John Sollows = at 742-2802.<span style=3D"font-size:11.0pt;font-family:"Calibri"= ,sans-serif"><u></u><u></u></span></p></div></div></blockquote></div><br><b= r clear=3D"all"><div><br></div>-- <br><div class=3D"gmail_signature" data-s= martmail=3D"gmail_signature">Dr. N.M.Hill<br>Fern Hill Institute of Plant C= onservation<br>424 Bentley Road, Berwick, NS, B0P 1E0<br><br>phone 902-698-= 0416</div> </div> --f403045e32809b031f056633f320--
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