I've just about quit replying on threads like this, but there is a lot of anecdotal material presented above that just doesn't agree with extensive testing by the Forest Products Laboratories and others.
What I've been relaying here is not based on anecdotes but on wood science of the past 30 years or so. Sources like Timell (1986): Compression Wood in Gymnosperms; Hakkila (1989): Utilization of Residual Forest Biomass; and the latest: Barnett et al 2014: The Biology of Reaction Wood.
First, all wood is 2.5 to 4 times stronger in tension than in compression.
No. Applies only to normal-grown wood. Very low tension strength is a major characteristic of compression wood. Many softwoods are "only" about twice as strong in tension compared to compression. Compression wood's tension strength is as much as 50 % lower than normal-grown wood, so around 1: 1.
Second, all varieties of wood produce compression wood on the earth side of branches. It's just that softwood's difference in growth between sky and earth sides is more pronounced.
Arguably true, strictly-speaking, but quite misleading. Compression wood in hardwoods and tension wood in softwoods is a fringe-level, suggested phenomena, compared to the well-established fundamental difference in how hardwoods and softwoods deal with gravity.
Barnett et al 2014: p. 2: [What is reaction wood?] "It is divided into two types: tension wood in dicotyledons, and compression wood in conifers."
Or take the classic, Hoadley's Understanding Wood, pp. 30 -32: "In softwood species, reaction wood forms principally toward the underside of the leaning stem" [...] "In hardwood trees, reaction wood forms predominantly toward the upper side of the leaning stem."
Anyone who's cut into reaction wood in softwood trunks and reaction wood in hardwood trunks can tell this much, it is quite graphic under the eye as well as under the blade. Philosophical relativities have little real-world weight.
In all the pre-1960 writings about wooden bows, any reference to compression wood in trunks or limbs advised to never make a bow from compression wood.
For the past 1 000 years, from the Pacific all the way to the Atlantic, over the vast Boreal zone of Northern Eurasia, the predominant and highly sought-after bow material was none other than compression wood (pine or larch). Compression wood has superb characteristics, once it's lousy tension strength is dealt with, as I wrote earlier. A backed compression wood bow is the only natural-material or other bow in the world that gains in reflex and cast when relative humidity rises, a pretty huge deal when living in the wet Northern woods, bow in hand.
Tuukka
