[NatureNS] Nova Scotian forest composition

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From: Donna Crossland <dcrossland@eastlink.ca>
Date: Thu, 21 Jun 2018 20:02:42 -0300
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Budworm mainly knocks out balsam fir, and only for a relatively short 
while.  Young fir will quickly spring up to replace the overstory 
trees.  That doesn't really alter the Acadian forest composition, at 
least not any more than it did 300-500 years ago and longer, but now we 
have more bF composition (according to my historical research) because 
we have caused so much disturbance. (In the late 1700s, much (perhaps 
two thirds of the province) of NS had burned from land clearance fires.  
Balsam fir and other early successional species filled the gap for a time.)

However, the exotics are hitting our long-lived, late-successional, 
characteristic species assemblages that are UNIQUE to the Acadian 
forest.  That is a sad fact.  Furthermore, many of those species were 
_temperate _species, with ranges that extend southward, and they should 
have remained well-suited for a warmer climate.  Most of them are also 
wind-firm, which is useful in windy NS.  They should hold up well, but 
we humans keep introducing pests that kill them off.   And so, a 'horse 
of a different colour' than budworm on many levels.  I cannot and do not 
predict the future, but note that our unique Acadian forest will be 
permanently altered, and replaced by other players (I have only some 
vague notions of what species they will be- perhaps many of them 
originating from the temperate climate of Asia, one of them will likely 
be Glossy Buckthorn, and seemingly favored species with David, though it 
is reducing biodiversity in fens and other sensitive sites).

I will not likely see a rise in Tennessee warblers in the monitoring 
plots that are located in mature hardwood and hemlock forests, but it 
will be hard to overlook them elsewhere if their population rise.  I 
remember seeing/hearing lots of them in NB in 1995.  It seems they were 
linked to more open and boreal-like situations, so maybe are not so 
well-suited to warmer southwestern NS, especially now that subsistence 
farmlands are growing up. Perhaps they might invade the hemlock plots as 
hemlock dies and early succession commences.  It will be interesting to 
note the suite of species that takes over for a short while.

All to say that forest disturbance dynamics in the Acadian forest is 
extremely complex and there is so little of the natural dynamic left 
intact, and it seems we are determined to meddle with it still.  Many of 
our assumptions come from boreal forest ecology (an amazing, but yet 
simpler system to our own), and so not entirely appropriate to NS.  Will 
the budworm return as it did some 40 years ago?  Perhaps not.  I am not 
quite certain what it would eat in some places.  A quick check of 
satellite images reveals that we have over-harvested our forests, so 
pickings may be meager for the bug this time around.  We have far less 
forest than 40 years ago, despite what industry/DNR informs us.  "Yes", 
there is regrowth on former farm lands, but that does not off-set the 
forests that have been stripped bare in many areas.  Older age classes 
have disappeared 'overnight'.  And now they are going back to remove the 
leave strips around swamps and going into the swamps are far as machines 
can go without disappearing.  Dreadful, short-sighted, increasingly 
desperate greed.

Must leave it here for another early morning survey tomorrow.  I am 
sleep-deprived from the longest day of the year that commenced at 3:35 
hr, and so much of this may not make sense.  The bird season is winding 
down quickly.

I truly appreciate hearing of bird populations' rises and falls, and you 
and others see headed our way.  It helps to make me aware of what to 
look for up ahead.

Happy solstice!

Donna


On 2018-06-20 5:19 PM, Laviolette, Lance wrote:
>
> Hi Donna,
>
> Budworm is a native insect however it, like non-native insects, will 
> change the composition of Nova Scotia forests and that was what my 
> original question was all about. As David has now pointed out, climate 
> change will also be a major ‘player’ in what the resulting forest will 
> look like in 20 years.
>
> Predictions of what things will be in the future are simply an 
> exercise in assumptions so will not be interesting to everyone. 
> Sticking with facts then, the budworm’s cyclical impact on Maritime 
> forests is as important as a non-native insect’s effect is. The impact 
> on bird populations is a well-studied phenomena. You mention that you 
> are seeing a few more Bay-breasted Warblers in the forest monitoring 
> plots. I can tell you that monitoring on Brier Island has shown that 
> the population of both Bay-breasted and Cape May Warblers have been 
> rising dramatically over the last 4-5 years. I expect they will 
> continue to increase, as they did 40 years ago as long as the Spruce 
> Budworm populations remain high in the Maritimes and the Gaspé. The 
> odd thing is that so far the expected rise in Tennessee Warbler 
> numbers hasn’t materialized in our observations. Let us know when you 
> start detecting more of that species on your plots and I’ll do the 
> same when numbers increase during migration on Brier Island.
>
> All the best,
>
> Lance
>
> Lance Laviolette
>
> Glen Robertson, Ontario
>
> *From:*naturens-owner@chebucto.ns.ca 
> [mailto:naturens-owner@chebucto.ns.ca] *On Behalf Of *Donna Crossland
> *Sent:* Tuesday, June 19, 2018 6:21 PM
> *To:* naturens@chebucto.ns.ca
> *Subject:* EXTERNAL: Re: [NatureNS] Nova Scotian forest composition
>
> It's best to avoid the 'company line' about "spruce budworm left 
> unchecked".  This is a topic that the forest industry uses to instill 
> panic to justify full scale harvesting of spruce and fir, complete 
> with a spray program, etc.  Budworm is a native pest and should not 
> enter the conversations over exotics.  It comes 'round every few 
> decades, as we know. Bay-breasted, Tennessee and other warbler species 
> can increase rapidly.  We can sit back and enjoy watching natures 
> responses to it. This year I observed a few more Bay-breasted warblers 
> in forest monitoring plots than previous years, and am questioning if 
> they are from an increased number resulting from the Qc population 
> that decided to settle in southwest NS this year instead of heading 
> farther north  after returning from the tropics.
>
> The forest industry and DNR would have us "tinker" with this this 
> natural disturbance agent.  But balsam fir was never "built to last".  
> Titus Smith referred to it as a nursery tree to shelter the growth of 
> other late successional tree species.  Early entry harvesting