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Index of Subjects
> Ron Neville, Plant Health Survey Biologist
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Hi Nick & All,
While there is no prospect of preventing tree death there may be=20
situations when intervention may be practical and desirable.
I also have a soft spot for Hemlock but have burned two as firewood=20
and, even when full of knots, it is easily split and burns well; good=20
for renewing fire from a few coals. The first was an ugly tree that was=20
damaged in youth about 20' up and had developed five or six upright but=20
spreading secondary trunks each about one foot across. Given this shape=20
it was even more of a ground hog than the typical hemlock. The second=20
was a wind throw with a trace of rot but it also burned well.
Where practical I would suggest converting dead Hemlock to firewood=20
because one gets heat along with the release of CO2. When a tree decays=20
in the woods (or elsewhere) all of the C is released as CO2. Compared to=20
climate change other wildlife/ecological problems are vanishingly=20
trivial so it makes sense to combat climate change where practical and=20
replacing petrochemical heat with wood heat is a way to do this.
Yt, DW Kentville
------ Original Message ------
From: "John and Nhung" <nhungjohn@eastlink.ca>
To: naturens@chebucto.ns.ca
Sent: 2/27/2018 1:57:19 PM
Subject: RE: [NatureNS] Notice of Meeting on Hemlock Woolly Adelgid
>Good points, and I=E2=80=99d be uncomfortable with some proposed intervent=
ions.=20
> Introduction of any exotic, for instance, has unpredictable=20
>consequences.
>
>
>
>I don=E2=80=99t think there=E2=80=99s any necessary conflict between attem=
pts to=20
>preserve hemlock and other sustainable forest management initiatives. =20
>For instance, I keep wondering about seed banks, which may or not be a=20
>good idea =E2=80=A6
>
>
>
>Hope you=E2=80=99re gonna catch some of the sessions, Nick. The MTRI-orga=
nized=20
>ones are probably more geographically conveniently-located. You could=20
>contribute substantively to the discussions!
>
>
>
>From:naturens-owner@chebucto.ns.ca=20
>[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=20
>is change and unwelcome.
>
>Let us first put it in a North American context with climate change and=20
>atmospheric N deposition.
>
>We can research the impact that has occurred where the pest has moved=20
>through from Virginia through New England.
>
>And then we can look at stand vulnerability factors. We stand to lose=20
>trees and some stands. The outbreaks will be heterogenous: stands=20
>receiving more N in SW Nova could be more affected. Cool ravines should=20
>be less affected. Stands near the coast may be less affected because=20
>there has been less temperature change over the past 30 y.
>
>
>
>From what I have read, things were not wholly disastrous. The trees in=20
>some infected stands were mainly killed whereas hemlocks in other=20
>stands were less affected and in some, most trees survived. The carbon=20
>stays in the ecosystem. This is habitat. A new forest takes shape and=20
>this normally includes in the US where hemlock trees have been killed, =20
>Betula lenta that we dont get here and Betula alleghaniensis (yellow=20
>birch) that we do.
>
>
>
>We should fight the things we can fight and influence such as=20
>clearcutting, unnecessary roads, poor land use and wetland loss.
>
>We can do all measure of things: fighting invasives broadly, spraying=20
>the budworm with bacteria and sprays, introducing organisms to fight=20
>adelgid or the sanitary removal of diseased hemlock. Or we can protect=20
>forest processes by reducing cutting frequency and intensity (this will=20
>mean less nutrient and organic matter, structure and carbon removal),=20
>using shelterwood management (maintains shade and moisture and=20
>structure), protecting by buffers ravines (shade and moisture) and=20
>wetland corridors, and setting up mature forest corridors (birds,=20
>mammals, herbs...and...?) throughout the forest. We cant stop this=20
>climate change but we can make our forests as healthy as we can. The=20
>forests will be dynamic and we can protect mature forest processes but=20
>not determine what the eventual forest will look like.
>
>
>
>Losing some hemlock stands does suck but any reactive response to=20
>adelgid can be seen in a larger perspective of processes.
>
>Let's fix unsound forestry practices and let the forest take care of=20
>itself. We would be pleasantly surprised on balance. Less hemlock, more=20
>yellow birch,white pine, red spruce and in 50 years, our forest may=20
>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=20
>Ohio State)
>
>Hemlock forests exhibit low species richness, and thus have low=20
>resiliency. In uninvaded forests of Ohio, hemlock dominates the=20
>vegetation, although other species are structured by environmental=20
>gradients. Structural equation modeling indicates hemlock has a=20
>negative influence on vegetation species richness, light availability=20
>and productivity. Thus, a likely future HWA arrival will result in a=20
>complete reorganization of these ecosystems, but impacts will differ=20
>across environmental gradients. Data from sites impacted by HWA 9-32=20
>years in West Virginia and Virginia indicate all hemlock forests will=20
>likely be impacted. Although mortality is initially slowed at higher=20
>elevations and on steeper slopes with northerly aspects, eventually,=20
>the duration of HWA invasion is the most important driver of mortality=20
>and ecosystem change. As decline progress, hemlock remains dominant in=20
>sites impacted for decades, although compositions are shifting and=20
>diverging across overstory hemlock decline classes. Some species,=20
>including the native evergreen shrub rhododendron (Rhododendron=20
>maximum) and other evergreen species including red spruce (Picea=20
>rubens), may be particularly influential during communit