Mazur Birch is not a species of birch, but is rather a wood figure whose original cause is unknown but which is hereditary (and therefor not a burl and not caused by a fungus, insect infestation, etc.). The trees that contain this figure grow primarily in the area on the Easter border of Finland and the Eastern border of Russia formerly known as Karelia. Because of that the wood is also known as Karelian birch although the name mazur birch is much more common. The spelling is also (much less often) given as "masur".
The figure is found almost exclusively in Betula pubescens (European birch, Baltic birch, white birch, etc) and Betula pendula (curly birch, silver birch, dwarf birch, etc). I have it anecdotally that it can appear in other Betula species but I have never seen any examples.
The figure is a pock-mark slightly like birds-eye in maple. Sometimes it appears just as splotchy ovals. It is often mistakenly called a burl, but as mentioned above it definitely is not a burl.
my samples: NOTE: these pics were all taken in very bright incandescent lighting ("soft white" at 2700K) colors will vary under other lighting conditions
both sides of a sample plank of mazur birch / Betula spp. --- HUGE enlargements are present.
end grain and end grain closeup of the piece directly above
mazur birch end grain scales showing nicely how the weird growth looks inside the wood
mazur birch slabs, all from the same vendor and all with both levels of enlargement
both sides of a mazur birch slab
planks, all from the same vendor and all with both levels of enlargement
two sets of planks with a closeup of each set
turning stock listed as mazur birch / Betula alba. These samples and the ones directly below are the only ones I've ever seen of mazur birch that was not either Betula pendula or Betula pubescens so I'm not sure the species listed is correct.
turning stock listed as mazur birch / Betula alba and a closeup. These samples and the ones directly above are the only ones I've ever seen of mazur birch that was not either Betula pendula or Betula pubescens so I'm not sure the species listed is correct.
mazur birch scales, all from the same vendor and all with both levels of enlargement
scales listed as mazur birch / Betula pendula
mazur birch veneer
mazur birch veneer incorrectly listed as "European mazur burl" veneer
veneer of mazur birch / Betula pendula, which had been incorrectly listed as "European burl" veneer
rotary cut veneer of mazur birch / Betula pendula, which had been incorrectly listed as "European burl" veneer
veneer, all from the same vendor and all incorrectly listed as "Karelian burl" veneer, which should just be "Karelian veneer". I'm sure these pieces all look shinier in the pics than in reality.
veneer, all listed incorrectly as "Karelian birch burl" which should be just Karelian birch
guitar and the head from a different guitar
really nicely done turned boxes - both levels of enlargement are present
6" mazur birch vase by Steve Earis. Thanks to Steve's excellent photography, very large enlargements are present.