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A friend of mine had a couple of huge old trees blow down on his property here in Alberta. White spruce a little over 32" near the base. I told him to save a few 30" long logs for me. There is about ten feet of branch free log at the bottom of each tree. It'll take a while to dry but I plan to split and quarter and then cut some 1" or so boards up and sticker them in my shop. Any reason I shouldn't do the work? Pitch pockets or other problems? It seems like it isn't a common top wood?

I’m in the middle of a build where the client requested white spruce. I sourced sets from 2 different trees from northern Quebec and processed them for physical testing by the method of Gore and Gillet (as I do with all my tops). I bought the material from a young luthier who does silviculture contracting up north during the summer. He knows how to split billets and saw to minimize runout. I still discarded the sets from one tree as too weak. The other was significantly stiffer, so I’m building with one of those.

It is similar to Engelmann, both in stiffness and density, as you might expect — the forest geneticist in me can assure you that they are very closely related, which is why they hybridize so frequently in Alberta and BC.

You can screw up the processing of otherwise perfectly usable top material, so think carefully before you run it through the bandsaw.


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Thanks Tim. I'll be careful although considering the price, I'll experiment as well!

If I recall LUTZ is a White & Sitka hybrid.
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Mike

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Mike Collins

Tim Mullin wrote:
"I still discarded the sets from one tree as too weak. "

As I understand it the limit in a top is stiffness: any top that is stiff enough will be strong enough. If the wood doesn't have 'wind shake' or some other defect you can leave a top with a low Young's modulus a bit thicker and it will work fine. Since Young's modulus usually tracks density pretty well in softwoods, the low density/low modulus top will generally end up lighter in weight, even though it's thicker. However, if the modulus is very low relative to the density, and there's no run out (which is a good reason to reject a top anyway), that can be a sign that there are problems with the wood akin to wind shake. This is usually linked with a much higher damping factor than normal; it taps like cardboard.

I've had very good results using low density/low modulus wood for tops, particularly if they're 'above the line'. It often happens that very low density softwood will actually have a higher modulus along the grain than you'd expect on the basis of the density, and those make particularly light and stiff tops.

A friend and I processed out a white spruce tree about 40 years ago. It had been cut because it was pushing somebody's porch off its foundation, and the tree guy called the first guitar maker in the 'phone book. We had him buck it into 2' lengths, and we split those into wedges that were about 4" wide on the outside as soon as possible. Once they were split we painted the ends with a couple of coats of cheap latex paint and removed the bark, to equalize the moisture loss through all surfaces. That took about a weekend in the spring. We square stacked the pieces on pallets in the shade to about 2' high, and covered the tops of the piles with tarps to keep the rain off, leaving the sides open. After about a week or ten days we sorted through the stacks. Any end checks were trimmed back an re-painted (only a few iirc). Blue spots from fungus were hit with 10% bleach. The pieces from the top wen on the bottom of new piles. We did this again a week or two later, and at least one more time after a month or so. We had very little drying degrade.

This was a yard tree, with some lean from being next to the house, so there was some fairly heavy latewood line in some parts. The density was on the high side for spruce in those areas. We used a lot of it for guitar bracing, made tops for guitars, and several bowed instruments as well. There were parts from higher up on the 'up' side of the tree with lower density and less pronounced late wood, and that made better instruments.

The bottom line: don't wait. Get that stuff split up ASAP or you could lose a lot of it. DAMHIKT

My forestry buddies with the Ministry of Forests rarely refer to white spruce, preferring to call it “interior spruce”, which includes the hybrid with Engelman. So, they would tend to call Lutz the hybrid between interior spruce and Sitka. Where the ranges and environments overlap, introgression among Sitka, white and Engelmann is the rule, rather than the exception.


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There's a guy in the northeast US that sells good quality White Spruce. It grows in an area that overlaps Red Spruce and visually they look the same. The stiffness is the same as well. The yield is lower (from what I hear) because White Spruce has a lot more knots than Red Spruce. I think I remember Mario uses a lot that he cut himself up in Northern Ontario.
As for Engelmann, I didn't like the tops I tried back in the late 70's or 80's, but I bought a bunch from a guy in BC Canada about fifteen years ago and it may be a hybrid because it's much harder and stiffer. The first tops I ordered were so good that I got a wholesale price and bought a total of fifty.

On spruce hybrids:
Harold J. Lutz did some field work on forest soils in the southern handle of Alaska after WWII and recognized a population of spruce there that seemed to show a blend of characteristics of the common Sitka spruce and (what was generally then called) white spruce. I understand his original specimens are in the Smithsonian.
The American tree taxonomist E.L. Little gave the hybrid formal taxonomic recognition in 1953 as Picea x lutzii.
A forest geneticist named L. Roche then studied spruces in western Canada in the 60s while doing his doctorate at UBC and documented the exceedingly common introgression among white and Engelmann spruce and pockets where Sitka was also involved. More recent studies using genomic markers have verified what Roche and Little both determined using morphological markers. Foresters in British Columbia are more likely to refer to “Roche spruce” rather than Lutz spruce, recognizing the more general introgression among Sitka, white and Engelmann. The idea that pure white exists anywhere in BC now seems unlikely, as pollen flies long distances and hybridization is so common, especially in the interior (hence, “interior spruce”).
When Roche returned to his native Quebec, there was much interest in the possible introgression between red and black spruce. Steve Manley in New Brunswick and Al Gordon in Ontario both developed data supporting this in the 70s, again confirmed more recently by genomic markers. It was a time when much research focused on the evolution and post-glacial migration of spruces around the northern hemisphere.
Meanwhile, Little identified in Minnesota what was thought to be a natural hybrid between black and white spruce, which became known as the Rosendahl spruce. Despite that some putative hybrid individuals have been found, natural hybrid populations have not, and the hybrid is quite difficult to make via controlled pollination (I’ve tried).
The hybrid between black and Sitka on the other hand is fairly easy to make by controlled pollination. Nevertheless, there is little overlap between natural populations of Sitka and black spruce, so not surprising that no introgression has been found.
Finding white spruce that are sufficiently large for production of soundboards is not easy, but they do exist (my friend here in Quebec has a room full of it, but few sets large enough for a Dreadnought). It would be reasonable to expect them to be similar to Englemann (the closest relative to white). The wood of white spruce is anatomically distinct from both black and red spruce.
Some of the red spruce that has been used for guitars has undoubtedly come from populations introgressed to some degree with black spruce. The wood from both species and their hybrid is very similar. Pure black spruce would likely make excellent guitars; the problem would be to find individual trees large enough (although I know there are some in northeastern New Brunswick).


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FWIW, if you measure the salient properties of the various spruces; Young's modulus along and across the grain, damping, and density, they don't differ much by species in any systematic way. I you control for density you can predict the Young's modulus along the grain (which determines stiffness along the grain at a given thickness) to within 10% in 60% or more of the samples, and all of the soft woods I've tested fall on the same line. Cross stiffness in most closely correlated with degree of quarter; nothing else even comes close to explaining the variation. Although a lot of folks claim to be able to tell Sitka from the other spruces by sound, I'm skeptical, and none of the others should be enough different to matter. Spruce is spruce. WRC and redwood follow the same long grain stiffness rule, but both normally have much lower damping than any of the spruces. The average density for any species tends to vary a bit, with Engelmann averaging a bit lower than the Euro I've tested, and Red and Sitka tending to be more dense on average, but there's a lot of variation and plenty of overlap. The densest piece of spruce I've tested so far was European, and 300-400 years old. I have some Red spruce that exactly matches a set of WRC for density, and stiffness both along and across the grain. You have to go by the piece, not the species.

Couldn’t agree more, Alan.


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Tim. Thanks for the description of what is going on with the spruce hybridisation. It is clearly only genomics which is going to be the tool to sort this stuff out properly.

I often wonder when buying top wood whether the species description is accurate since it is so difficult for an amateur to actually recognise a particular type of spruce. Not that I am saying that the suppliers are cheating, rather that they themselves may not really know what they are being sold to by the wholesalers.

It reinforces the point that Alan keeps making that you have to test the particular piece of wood in front of you to decide on how to treat it.

Dave

Well, yes and no. The guys I trained under had already sorted out the genecology of spruce quite thoroughly, based on nothing more than morphological markers, crossability and patterns of post-glacial migration. They were clever dudes. As a result, the role of introgressive hybridization in boreal conifers was pretty well described by the mid-70s. Later, access first to allozyme markers, then RAPDs, and on to dense mapping of SNPs only confirmed what had long been accepted and the taxonomic classification of spruce species hasn’t changed. We even now have draft whole-genome sequences for both white and Norway spruce — quite a feat, given the massive size of conifer genomes. Few tree genera have such a history of investigation into their evolution (although pines are up there). For these, genomic tools are providing a means to pose and test hypotheses of evolution much more easily.


That’s a valid point, but as Alan Carruth points out, from a building perspective, “spruce is spruce”. I often smile when I see discussions about the merits of Italian spruce versus German spruce, and the like. They’re all the same species, known to me and my colleagues as Norway spruce (Picea abies), where we’ve long known the proportion of total genetic variation found among trees in a stand is not much different from that among populations across the range (a typical finding for boreal conifers). No real point being pedantic about the nationality of the tree.


Exactly.


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The white spruce I have was sourced by Ted Davis from Labrador in 1986. It is quite dense, and correspondingly stiff. The grain is very tight, and it is light in color. I compare the physical characteristics to some of the denser red spruce I have cut, and a far cry from typical Engelmann (other than the color). I have also found that white spruce is more prone to defects than red. Expect to encounter pin knots, pitch pockets, checks, and fungal staining, particularly near the heart. This is primarily due to its growth habit, where it does not shed its limbs as readily as red spruce.

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John

Thanks Tim. Very interesting, Dave

Looks like I won't be trying it just yet. I've got enough firewood to last me for a while though!

Heart rot generally starts at the base, progressing up the trunk. You may find some solid, usable wood further up. If nothing else, at least some bracewood.

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John

Thanks John. I've asked my guys to keep anything that looks salvageable. It's about a five hour drive from here otherwise I would go and check it out. I'll be spending lots of time on that property this summer though. Should definitely be able to get a load of bracewood and maybe even some tops if I'm lucky.

https://www.youtube.com/results?search_ ... los+guitar

Perhaps check out some of these videos before you reject narrow boards for tops. One video on how to make better guitar tops explains why it may often be better to use multiple narrow pieces, for example four piece tops. I think it is based upon the impracticality of cutting proper runout and cross grain orientation on a wide enough board for typical two piece tops. Wouldn't we all use one piece tops if you could find perfect wood that wide? We cannot really, so we give up and use two piece.

True that. I made a four piece top and back for the one I built for a 2" x 4" competition a number of years back. Resawn slices from a pine 2" x 4". It sits on a stand in my kitchen and still sees regular play.

Other than the possible cosmetics, I would have no problem with multi piece tops. I believe Torres used three or four piece tops. I have even seen different species used. Just off hand, I recall seeing a three piece top made from two pieces of spruce and a piece of cedar in the middle.

Here is a photo of the Labrador white spruce cut in the 1980's. This is an 0 size guitar top, and the grain width ranges from 25 to 30 per inch. Stiffness rivals the best red spruce I have cut.
One of my early guitars (1977) has a four-piece Ponderosa pine top, and the paw-paw top L-00 inspired guitar (1980) is ten-piece. Around here, a big paw-paw is 4" in diameter.

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John

Ha! Awesome and inspiring John. Beautiful looking wood. I'm very glad there are pros like you still around and contributing and teaching. We've lost a few here over the years due to age and other things. I've seen history repeat itself too often on various forums around best glue etc. which I can identify with back in my earlier years as well. "Lessons learned" seem to get buried very quickly but I guess it keeps conversations and forums going and certainly helps up and comers. Newer ways of doing things happen from time to time IME but there really aren't too many compared to things learned a long time ago. History repeats itself often.

I wonder if..........some of us got use to associating a certain velocity of sound with a certain material ?? The difference between any spruce and cedar or redwood is obvious, but how about a difference between spruces ?? I have quite a bit of tops (but only a few sitka ) so perhaps I'll tap a bunch of tops later today and check it out.

Acoustic velocity is the standard surrogate used to evaluate MOE in standing trees. It is used by several tree breeding programs around the world.
We’ve used transducer equipment in the lab with standard samples to do the same thing. Ideas have also floated to use acoustic velocity rather than standard machine-stress grading in countries like New Zealand that require it for structural timber, but I don’t think it was ever adopted. I’ve often thought a clever lab tech could build a mini-version for guitar tops, but I already use Trevor Gore’s methods on my tops, which likely give more useful info.


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The velocity of sound of a compression wave (c) in a solid is a function of the density and Young's modulus (E). It makes a useful 'figure of merit' in the sense that a piece of soft wood with a high c will usually end up making a lighter weight top that's easier for the strings to push. However, the really important thing in a top is stiffness; it has to be stiff enough to withstand the static string load or it's useless. Stiffness at a given thickness is determined by the Young's modulus, and just knowing c by itself, without the density, won't tell you what the E value is.

The reason 'high c' wood works well is that the Young's modulus tracks density remarkably closely in soft woods, and the relationship is pretty close to linear in the range of densities we see. Since the stiffness of a plate goes as the Young's modulus and the cube of the thickness you can make a top with low density and low E a little thicker to get the stiffness up and end up with a lighter plate.

Violin bow makers have used the 'Lucci meter' to choose bow wood for decades. It basically gives a reading of the speed of sound of the wood, and an indication of how much the wave is dissipated as it travels along the stick, if I understand it correctly. This gives an indication of how much runout there is in the wood, which is important in a bow.