Yew Growth Rate

[Rod]

I guess it is always a gamble without knowing the moisture content and specific gravity, even then you won't know for sure until you get the bow tillered.
ring count alone is not much of a guide and in the mediaeval illustrations we do see some very fat bows, so what does that tell us?

Rod.

[Phil Rees]

I recently had the opportunity to speak to a Botanical Taxonomist from Kew. I was able to ask him if there was a correlation between tree size and tree age in the same species of tree at differing geographical locations. His answer was that the growth rate depended on the availability of nutrients, water and of course sun light so no direct size/age relationship will exist. I then asked if there was a correlation between growth rings per inch and the mechanical characteristics of the wood in terms of modulus of elasticity. His answer was quite surprising. He said that there can be small variations in the chemical cellular structure of the wood that could make some wood with low growth ring counts as stiff if not stiffer than the same species with a much higher growth ring per inch depending on the environmental conditions in which the tree was grown. But, he concluded that, generally, it's safe to assume that the higher ring count woods are a little stiffer than lower ring count examples.

[DarkSoul]

Quite on old topic here, but I think my reply could my of use here. I haven't been on PA for a long time

I've made about seven yew bows to date. Still have a few more yew staves in stock, and I've seen and handled more staves from friends as well. So I know a thing or two about Dutch yew. Yes, Dutch yew only, because I live in the Netherlands. Dutch yew comes in two 'varieties': the good and the bad. Holland is low altitude by definition: my yew comes from about 10 to 50 feet above sea level... So the (what I consider) good yew also comes from low alitude. That means to me that the altitude ALONE says very little. However, I have found a very clear correlation between growth ring density (rings per inch, rpi) and the mechanical wood characteristics.
The 'bad' Dutch yew primarily comes from gardens. Newbie Dutch bowyers can get really excited about the yew log they've found. But I rarely get excited about that garden yew, knowing that it is the 'bad' yew. Those yew trees have an rpi of like 10 to 20 (occasionally 5 to 8 ). The trees look very healthy, with a big canopy and a lot of leaves/branches. A lot of light reaches the often solitary trees, and they are cherished with plety of water in our already moist country. The wood looks as follows. The demarcation between the sapwood and the heartwood is very faint. The heartwood is very dull colored; not a very bright or dark shade of brown/orange. The wood is soft, brittle. Slivers of wood from a dry stave simply snap in half with a clean break.
The 'good' yew really is completely different in every aspect. It typically does not come from a garden, but grows 'in the wild', so in a forrest or alongside a road, sometimes in graveyards. The ring count of typical Dutch 'good' yew ranges from 20 to 50 (even 60) rpi. This is also reflected in the living tree: it just looks poor and aged. It leans to a side, may lack a real canopy, or does not have a single trunk but multiple smaller trunks. The smaller the canopy, the less leaves to catch sunlight. So I think you can actually make an educated guess on the ring count when you only take a look at the canopy, and compare that to the trunk size. The 'good' Dutch yew often grows on very poor (sandy) soils, with little water and nutrients. It may grow under large beech or oak trees, so very little sunlight actually reaches the canopy. The wood is usually very dark salmon/orange, even approaching brown. A very clear demarcation between the sapwood and heartwood can be seen. The wood is very hard (SG up to 0.90 of the heartwood is really possible, but 0.75/0.80 is typical). The wood is not brittle at all: a sliver of dry wood just bends: it's elastic as hell. From a stave you could pull off small strips of wood, instead of breaking off splinters.

The 'bad' yew will make a bow. I've made two bows of such a piece of 'bad' garden yew. You need to design the bow a bit bigger: the wood is not as dense, so you need more volume to reach the same mass. For a light weight bow (up to 50# or so), little set can be expected. It's just a much softer wood, so you need to be more careful handling the wood/bow, and the wood is more difficult to work with because it tends to shatter under you tools. Planing and scraping tends to leave it rough.
Don't get me wrong: 'bad' yew with a very low ring count can make a great bow. So it's not so 'bad' as I initially thought I recently made a 35# ELB from a 15 rpi piece of garden yew. Tiller was not perfect, cross section was a very deep D-shape at least 3:4 (thickness:width) ratio I guess. The bow hasn't been shot much, yet, but it has been shot about 100 shots or so. Set is very low, and with its low physical mass and thus lightweight tips, it's a pleasure to shoot and pretty fast!

The 'good' Dutch yew is simply a great wood. It's really beautifully grained and coloured. I've never had a bow break with good yew, and rarely heard stories about a bow failure with it from my friends. The wood is very hard, but works very good. Scraping the wood will leave it very smooth. It's pretty stiff, and I wouldn't be surprised if it were better than the "high altitude Oregon Pacific yew" in many aspects, but quite frankly I don't know, because I have never worked with Pacific yew. I do think the 'good' Dutch yew is not well known, simply because most bowyers in my country use the 'bad' yew, and have never seen the 'good' yew. It's quite rare, and since we cannot just go into the woods to cut a tree outselves, we are doomed to the garden yew, which is 'bad' yew by definition.

[PatM]

"Garden" yew will tend to be a Yew cultivar rather than simply a "Wild" Yew planted in a garden. This means it may even be a hybrid of two species or a type selected for a tendency to be much leafier and dense of foliage. This likely explains the less desirable characteristics.
 Here in Canada there are both types commonly found planted next to houses or in gardens. The Wild type is very distinct in that it has quite sparse foliage and it is always a tree. Quite often I see stave quality trees of 6-10 inches in diameter that I would assume were planted around the time the house was completed. That would put them in the range of 80-100 years of age.
 I have never managed to obtain a stave but branch and trunk samples of this wood are excellent in characteristics.
 I would think that the relatively severe climate but optimum healthy growing conditions are probably close to ideal for producing quality wood. This despite the fact that we're not high up here at all.
 Oddly the native Canadian Yew (East of the Rockies) is a stunted ground shrub. It must still be recovering from the last Ice Age.
It would be a miracle to even find two "trunks" that could be spliced into a sapling bow. Too bad that it does seem to be high quality but it doesn't even get more than an inch in diameter.

[71flh]

This interests me as well. I Have several yews on my property ranging from 10" or so up to over 20" in diameter. Was planning on harvesting some of them this year for staves.  I live in the  hills and small mountains of the Umpqua valley area of Oregon at about 1200 to 1300 foot elevation .

I know a little about Pacific Yew, which is what you have. I grew up in Oregon and now live outside Seattle. All of the trees that you have (over 10") are at least 80 years old. Take care in harvesting them for you will not replace them in your life time, and watch who you tell you have them or someone else may help themself. I was in your area over the 4th visiting friends, watched the elk outside Reedsport. I have 3 Pacific Yew bows now, 2 long bows and a recurve. By the end of the month I will have 2 self bows.