At what age do commercial oak trees get cut?

JoeS · 11 Jul 2022

I'm planning this year to take down a couple of trees on a property i part own in France - there are lots of hardwood trees of about 20-30 years old which are well overdue being thinned out. I'm thinking of taking an Alaskan style mill out with me and having a go at milling with no particular goal (no laughing at the back). But it made me think...many of the trees look like they wouldn't yield that much quality timber at the moment...

There are a huge variety of trees on the land, some hundreds of years old (i won't be cutting these down) but it got me curious - what is the typical age/diameter of a slow growing tree like an Oak, which is then used for commercial use in construction etc. At what point does the tree become commercially viable?

I'm sure some of the timber wizards will be along to explain things to me.

Adam W. · 11 Jul 2022

Not much smaller than 2' ø at breast height for milling.

Sgian Dubh · 11 Jul 2022

To expand a little on Adam W's post, 2ft diameter at breast height equates to very approximately 70 - 75 years growth in a relatively mild temperate climate, e.g., the UK, France, Germany, etc. A very rough way to estimate a tree's age is to wrap a measuring tape, piece of rope, or similar around a tree's bole at about chest height to find the circumference. Each 1" of circumferential length fairly typically equates to one year's growth. A 2ft diameter circle has a circumference of about 75" via the sum πd (pi * diameter), so a 2ft diameter equates to roughly 70 - 75 year's growth. This rough and ready methodology for estimating a tree's age assumes that each year's growth adds ~3/8" (~9 mm) to the girth of a tree's trunk and limbs.

Clearly there are really too many assumptions about how much a tree will grow in the above ready reckoner and there are many exceptions and variations. On the other hand I have used the methodology outlined to estimate the age of trees where their initial germination is reckoned to be known within a reasonably small timeframe and in a fair number of cases estimated age correlates quite well with those 'known' germination dates. For example, arboretum owners are frequently able to identify when a particular tree either germinated from seed or was planted as a small sapling. Similarly, known dates of land enclosure or hedge planting for farming purposes are quite often identifiable via old maps, historical family knowledge, where it's known or assumed that pre-existing trees may have been incorporated into the new hedge or trees self-seeded some time after the new hedge was laid. Slainte.

Adam W. · 11 Jul 2022

If you're doing oak framing and are happy with bark and waney edges with one good side and halve the log down the pith, then you can get away with a much smaller tree than 2' ø.

custard · 13 Jul 2022

This is why it's common to have some Chestnut included amongst Oak. Chestnut has similar working characteristics to Oak and thrives under similar conditions, but it's ready for felling twenty years earlier. Not so much because it's all that much faster growing, more because there's a lower ratio of sap to heartwood.