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Hello Fred, David P., Jamie, Nick & All, Dec 30, 2015-Jan 1,
2016
Having dealt with more urgent matters I can now get back to this thread.
For a start I will comment on a quote from http://pinicola.ca/limnutr.htm
"In tropical rainforests it was easy to understand that most nutrients were
held in the biomass, because these were among the lushest places on the
planet, but had some of the poorest soil, often only 2-4 cm deep. Through
the 1970's and 1980's the realization spread north that this was also true
of temperate and boreal forests, and that the deeper soils of northern
forests only meant that the processing of nutrients through the forest floor
was somewhat slower than it was in the tropics."
Unfortunately we too frequently have landscape with soil depth of 2-4
cm. On the basis of water limitations alone such soil depth can support only
stunted runts or, given an assured supply of seepage/stable high water
table, relatively large but slow growing trees with a disk of roots grafted
to or woven around the roots of nearby trees. Such sites are extremely
vulnerable to prolonged dry periods which are sufficient to stop seepage or
lower water tables (or highway ditches which cut seepage off).
Soils with fair or better water holding capacity and more than 1 metre
of rooting depth can be expected to support continued tree growth and
survival under conditions experienced to date. So thank heavens for such
sites.
Being born a tree hugger who knows that only sound ideas, well supported
by a fabric of objective observation, can lead to sound management
decisions; this thread is of great interest to me. My former professional
background (retired 21 years and details fade quickly but the take home
messages are still clear) also overlaps much of this topic: PhD in Plant
Physiology and hired to cover Tree Fruit fertilizers and nutrition with
emphasis on Apple. This implied, among other things, a knowledge of soil
chemistry and soil physics because I soon realized that by far the most
important factors limiting growth and productivity of tree fruits in NS were
physical in nature; especially those related to drainage, aeration and
rooting depth. And, most importantly, this involved soils which had been
converted to agricultural uses because they had better physical properties
than sites left in woodland. If some of the better are poor then the worse
must tend to be very poor.
This dovetails with prior undergraduate experience as a member of a
Forest Ecology team where we had opportunity to see a wide variety of
woodland; much of it never cut but unproductive in the extreme.
Experience on a small area of the home farm also feeds into this
interest. Dates, except recent ones, are approximate because it would take
much digging to unearth exact ones. To make a long story short, about 2
acres of woodland was selectively thinned in 1943 to extract White Pine logs
plus firewood and foster growth of the remainder. It was then heavily cut in
1953 leaving only scattered trees too small for lumber, pulp or firewood. In
2000 it was selectively horse logged for White Pine logs and pulp and was
ready for a further selective cut by 2009. The White Pine trees continue to
grow like weeds i.e. no indication that previous cuts have impaired
subsequent growth.
At this point I wish to pose some questions. Has the decrease in
productivity after cutting, as noted by David P., been observed/measured or
is this decrease just postulated ? If observed, is it seen exclusively or
predominantly on clear cut sites ? And is this decrease most evident where
subsequent development of plant cover is spotty or slow ?
There are a host of reasons why a harvest, if not well done, could
decrease subsequent productivity. But loss of soil Ca, due to removal of
biomass, is not even close to being included. Also Dave, I think it is a
mistake to assume that waterways (Salmon) and woodland soils will be
affected by acidic precipitation to the same degree. While it is true that
waterways will usually be spring fed to some degree, much precipitation
reaches waterways directly and by runoff from swamps, bogs and nearby slopes
without ever passing through a soil. And the buffering capacity of waterways
is much less that even sandy soils.
On the other hand application of limestone to woodland soils would do no
harm and could in time bring the pH of waterways up a bit. In that vein,
disposal of biosolids is a problem and spreading some on clear cuts, on an
experimental basis could kill two birds with one stone. N is I suspect
commonly deficient in woodland soils.
Acid rain generated much concern about 40 (?) years ago so I crunched
the numbers and concluded that potential effects on soil composition were
minute compared with other forces. Many considered the overall effect on
forests to be positive due to the N supplied.
Nick has not responded to my question yet; busy or away I suppose. Perhaps
someone else can answer the question I posed to Nick on Dec 27; it being; "A
key question in this discussion is what fraction of soil calcium is under
consideration ? Is this exchangeable Ca and soil was sampled to what depth ?
"
I can imagine that one harvest could remove 27% of exchangeable Ca in
the most bioactive layers of a Podsol (Spodosol), although I don't have
sources at hand to confirm this, because exchangeable Ca in the upper soil
layers is a minor fraction of total. Most will be in soil minerals, root
tissue and other organic matter. Weathering of soil minerals is too slow to
satisfy needs of an annual crop but within the lifetime of a tree it can be
substantial. And the CO2 released by respiring roots and soil organisms
generates H+ which speeds weathering of minerals. Annual crops must grow
roots rapidly, do the job and die. Tree feeder roots at depth function year
round Thus leaching of N from apple orchard soil is very low.
In a Podsol, substantial Ca is lost each year as leachate and most
eventually will go to deep percolation or waterways. [Going back a few
decades in memory; Na,Ca & Mg are the mobile cations, being proportionally
well represented in the soil solution and Cl, NO3 and SO4 are the mobile
anions; K & PO4 being relative immobile.] In the Kentville area I
estimate that roughly half of our precipitation is consumed as
evapotranspiration and the remainder goes to runoff or deep percolation. In
cooler/wetter parts of NS I expect the fraction used by evapotranspiration
is even less.
In a relatively heavy soil with good structure most of the drainage will
be between peds so only the interped spaces are exposed to large leaching
losses. In very light soils, with no ped development, leaching losses could
I expect deplete much of the exchangeable Ca until drainage stops and Ca
begins to build up again by soil organic matter decay and by weathering of
soil minerals. In soils of moderate texture, such a Kentville Sandy Loam,
most subsoil drainage is along faces of large hexagonal elements (10-15 cm
across as I recall). In short the intensity of leaching loss would I expect
be highly dependent upon soil texture and profile features.
Typically about half of tree dry weight is above ground and half below
so where, as is usually the case, only the above ground part is harvested
appreciable nutrients are left in the ground. In above ground parts much Ca
is deposited as Ca oxalate crystals in the phloem and soon isolated from the
living tree by bark formation. I don't recall having seen sections of root
phloem but likely the same applies. And unlike above ground bark, root bark
is quickly subject to decay during the life of the tree.
Enough for now.
Dave Webster, Kentville
----- Original Message -----
From: "Fred Schueler" <bckcdb@istar.ca>
To: <naturens@chebucto.ns.ca>
Sent: Thursday, December 24, 2015 12:28 PM
Subject: RE: [NatureNS] Red Herring & Forestry
> Quoting John and Nhung <nhungjohn@eastlink.ca>:
>
>> Yeah, I get the impression that the main problem with the Point Tupper
>> monster is its size. A smaller operation might have fit in quite nicely.
>> Of course, the NewPage surprise added to the mess, but mess it is, and I
>> hope the government ad the operators can ramp back its biomass
>> consumption
>> to a more sensible, sustainable scale.
>
> * I was crafting a more complex reply to this thread, but I'll just say
> that the problem with biomass harvesting from forests is to get the
> nutrients removed in the wood back into the forest so successive
> generation of trees can grow at a decent rate. We tried to deal with this
> in our county forest here but certain foresters reacted so negatively to
> the question of fertilization that the advisory committee was illegally
> terminated as a consequence - but here's our discussion of the nutrient
> question in forests that are having wood removed -
> http://pinicola.ca/limnutr.htm - on sand and limestone we've got very low
> intrinsic levels of nutrients, but the problem exists in all woods if
> they're intensively exploited.
>
> fred.
> ==========================================================
>>
>> Fingers crossed for a mild winter, with minimum demand for firewood! All
>> this tells me we still need to take solar heat and other renewable
>> sources
>> more seriously.
>>
>> -----Original Message-----
>> From: naturens-owner@chebucto.ns.ca
>> [mailto:naturens-owner@chebucto.ns.ca]
>> On Behalf Of Stephen Shaw
>> Sent: December 24, 2015 11:59 AM
>> To: naturens@chebucto.ns.ca
>> Subject: RE: [NatureNS] Red Herring & Forestry
>>
>> Ed Darby? Abraham Darby I around 1709 modified the blast furnace that
>> had
>> already been evolving for over a millenium, to consume coke instead of
>> charcoal as the source of carbon that formed the carbon monoxide used to
>> reduce raw iron oxide to pig iron, the starting point for other iron
>> products. Charcoal gave a purer iron product, but making coke from coal
>> proved much cheaper than making charcoal from harvested trees, by then a
>> scarce commodity. For both charcoal and coke, a main byproduct was/is
>> CO2
>> gas from the finally oxidised carbon, released into the atmosphere. The
>> cheaper Darby coke method, later improved, caught on rapidly: a gnomic
>> irony
>> of this is that while saving some of the CO2-consuming much diminished
>> forests from approaching extinction, it led rapidly to much greater iron
>> production via burning fossil carbon that underpinned the Industrial
>> Revolution in Britain, which in turn led to ever increasing CO2
>> emissions,
>> eventually worldwide.
>>
>> On a lesser point not covered by reporter Aaron Beswick's article in the
>> C-H
>> that Dave referred to, if you had tried to get a few cords of 16" cut
>> firewood for your wood stove in early 2015, as we did, you would have
>> found
>> that initially, none of the local suppliers around Halifax could get any
>> logs, because they believed that such wood that had been harvested was
>> nearly all going directly to Point Tupper biomass monster, because that
>> had
>> been built too large for the available supply of so-called 'waste' wood
>> and
>> bark. Central planning at its very best. Our supplier eventually got
>> some
>> logs from New Brunswick, but the price went up considerably.
>> Steve
>> ________________________________________
>> From: naturens-owner@chebucto.ns.ca [naturens-owner@chebucto.ns.ca] on
>> behalf of David & Alison Webster [dwebster@glinx.com]
>> Sent: Wednesday, December 23, 2015 7:12 PM
>> To: naturens@chebucto.ns.ca
>> Subject: Re: [NatureNS] Red Herring & Forestry
>>
>> Hi Nick & All, Dec 23, 2015
>> I have only few minutes so will deal with the "gnomic" question first
>> and return later to the rest.
>> It was a new word to me so I had to consult a dictionary which
>> referred
>> me to sententious= Aphoristic, pithy, given to the use of maxims; (of
>> persons) = fond of pompous moralizing; maxim= A general truth drawn from
>> science or experience.
>> I think we should both plead guilty to the "gnomic" charge and be
>> flattered. As for the "pompous moralizing"; I am frequently inclined to
>> quote the King James Bible but then remember: "Be not righteous over
>> much,
>> neither make thyself over wise: why shouldest thou destroy thyself ?";
>> Ecclesiastes 7:16; and decide not to.
>>
>> Merry Christmas All & A Happy New Year
>>
>> ----- Original Message -----
>> From: Nicholas Hill<mailto:fernhillns@gmail.com>
>> To: naturens@chebucto.ns.ca<mailto:naturens@chebucto.ns.ca>
>> Sent: Wednesday, December 23, 2015 4:32 PM
>> Subject: Re: [NatureNS] Red Herring & Forestry
>>
>> A friend recently accused me of being "gnomic", and ill-educated lout as
>> i
>> am, i took issue at being called a gnome, but moving into this here case
>> at
>> hand, I think the gnomes have it: "And warning that use of biomass is not
>> green is perhaps already an effective way to indirectly kill trees." Not
>> exactly gnomic but not entirely designed for clarity and explicitness.
>> Then
>> we have: "And if not now, then without doubt in the future." This non
>> sentence leaves us without a doubt in the future waiting with and like
>> Godot
>> for some Christmas clarety.
>>
>> Seriously, I see Dave's point and Jamie's. England found a way through
>> Edward Darby to stop using beech trees for coking to make steel; Darby
>> figured out how to substitute coal for wood and thank god because England
>> had run out of most decent sized trees and was charcoaling most of its
>> forests. David is right that the first quotation is an overstatement but
>> Jamie's point was most welcome in today's Herald. We not only are running
>> the risk of losing good forest but we are running down our forest soils
>> so
>> that tree regrowth is poor, forest composition is weedy, wildlife
>> suffers,
>> and the carbon balance (ie. that less carbon dioxide is being emitted
>> than
>> would be if we allowed forests to grow and used conventional fossil fuels
>> in
>> the most efficient manner) is questionable. We want to move away from
>> "Green" that is not sustainable for wildlife and I would put biomass and
>> large scale hydroelectric both in that unsustainable class.
>>
>> Good on David and Jamie, the environmental critic and the advocate.
>>
>> Merry Christmas guys
>>
>> Nick
>>
>> On Wed, Dec 23, 2015 at 2:56 PM, David & Alison Webster
>> <dwebster@glinx.com<mailto:dwebster@glinx.com>> wrote:
>> Dear All, Dec 23, 2015
>> There is an article on biomass in today's Chron. Hrld. page A3
>> "Biomass
>> may be less than green: report". I could not see how to extract a link to
>> this article.
>> The warning was issued some years ago to "Beware of false prophets"
>> and
>> if this article is at all accurate then Jamie Simpson and Aaron Ward may
>> qualify to some extent.
>> These biomass plants leave much to be desired and constructive
>> criticism
>> will hopefully lead to better context integration in future but saying
>> that
>> "...the province is not capable of proving that harvesting for biomass is
>> better for the environment than burning coal." is misleading in the
>> extreme.
>> First of all it is an example of deplorable prose because
>> superficially
>> it would appear to say that burning biomass for power is no better for
>> the
>> environment than burning coal. Unless huge amounts of CO2 are released in
>> the course of cutting, hauling and preparation for burning then the above
>> would be false.
>> But burning of biomass is not mentioned; only harvesting for biomass
>> is
>> mentioned in that quote. And true enough "harvesting for biomass" uses
>> energy for no purpose if the biomass is not subsequently burned and would
>> not help the environment in any way. And the province, being just an area
>> of
>> land would be unable to prove anything.
>>
>> Getting back to the heart of this question; when a tree which has
>> fixed
>> carbon for say 100 years is cut down, it is entirely correct that another
>> tree of equal size and carbon content does not spring up to replace it in
>> less than 100 years (unless a faster growing tree is planted). So yes
>> there
>> often is an apparent lag. But if done astutely, say by thinning
>> overstocked
>> trees sufficiently early, then this apparent lag will shrink nearly to
>> zero.
>> And this may be repeated on the same ground two or more times depending
>> upon
>> details.
>>
>> But what are the alternatives ? If a tree dies and rots in the forest
>> then all of the carbon is eventually released as CO2 after being recycled
>> through a host of fungi, insects , etc. In event of forest fire then huge
>> amounts of CO2 are released in one slug. And some may have noticed that
>> large areas of western forest were burned this year; (some carbon bank).
>>
>> Going back to that 100 year old tree which was cut, and standing back
>> a
>> bit, it can be seen that the perceived lag in carbon capture is an
>> illusion.
>> The carbon has already been captured. The tree, over the period of its
>> life
>> fixed carbon and atmospheric carbon was decreased accordingly. Even if
>> that
>> entire tree is burned; trunk, branches and all roots, the amount of CO2
>> released can not exceed the amount which that tree has fixed. So the true
>> lag is zero.
>>
>> There is more than one way to kill a tree. I became alarmed about
>> 1990
>> because Spruce trees, normally long lived, were starting to die
>> prematurely.
>> At first I suspected air pollution and this may be in play to some
>> extent.
>> But over time I have became convinced that moisture stress was the
>> dominant
>> cause. Trees evolved for loss of feeder roots. As moisture is
>> extracted
>> to the wilting point, at a given level, death of feeder roots will soon
>> follow and when moisture is replenished a new set of feeder roots will
>> eventually develop. And long periods without rainfall in NS go way back,
>> as
>> growth rings here record, but if repeated too frequently then trees
>> become
>> overwhelmed by fungi invading dead extension roots leading to invasion of
>> major roots.
>> I don't have the figures extracted to prove it, but I think climate
>> change has already led to more erratic precipitation during the growing
>> season here.
>> And warning that use of biomass is not green is perhaps already an
>> effective way to indirectly kill trees. And if not now, then without
>> doubt
>> in the future.
>>
>> Yt, Dave Webster, Kentville
>>
>>
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>
>
>
>
> ------------------------------------------------------------
> Frederick W. Schueler & Aleta Karstad
> Mudpuppy Night - http://pinicola.ca/mudpup1.htm
> Vulnerable Watersheds - http://vulnerablewaters.blogspot.ca/
> study our books - http://pinicola.ca/books/index.htm
> RR#2 Bishops Mills, Ontario, Canada K0G 1T0
> on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
> (613)258-3107 <bckcdb at istar.ca> http://pinicola.ca/
> "[The] two fundamental steps of scientific thought - the conjecture and
> refutation of Popper - have little place in the usual conception of
> intelligence. If something is to be dismissed as inadequate, it is surely
> not Darwin [, whose] works manifest the activity of a mind seeking for
> wisdom, a value which conventional philosophy has largely abandoned."
> Ghiselen, 1969. Triumph of the Darwinian Method, p 237.
> ------------------------------------------------------------
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