Oak trees
Native to the UK there are two types of Oak tree, Pedunculate and Sessile, these legendary trees can reach 40 metres in height and have a girth of 9 metres (The Major Oak in Sherwood Forest has a girth of over 10 metres). The iconic Birnam Oak in Perthshire has a 7 metre girth and is thought to be around 600 years old.
Oak trees love an open growing situation and in these conditions will develop a wide spreading crown with very large branches which can be harvested without killing the tree. This process was common until coal took over 200 years ago (see articles on pollarding and coppicing). In Southern England, many of the Oaks planted during Elizabeth 1 reign survive today. She is said to have ordered mass replanting as she was concerned that ship building was causing a decline in their numbers.
Oak trees absorb the most CO2, act as host to more wildlife, and are more bound in UK history than any other tree species. Oaks have their threats but are coping well in the UK and are a very important part of our ecosystem. Britain has the most ancient Oaks of any European country.
When you hear them called English Oak, Scottish Oak etc that really only refers to the tree’s origin not to the type of timber or tree, although the term English Oak and Pedunculate Oak are interchangeable. The origin of a tree does play a major part in the timbers strength, character and stiffness properties. Where growing conditions are more difficult (generally the further North you go) the wood is harder, where more favourable conditions produce less density but more uniform growth. Here in Scotland we tend to get very dense Oak with lots of character.
There is a difference between an ancient Oak growing very old in an open environment and Oak trees grown close together to produce a sustainable high quality building product. France have an excellent Oak forest management system looking hundreds of years into the future. Done correctly, Oak can be harvested at the same time as maintaining and even expanding forest area, trees thrive in a well managed forest often more than if left completely wild. Unfortunately in the UK we have had a shorter term view since Victorian times and concentrate on faster growing softwood and clear felling as our main forestry activity. Fortunately the value of ancient Oaks to the environment is getting a lot more attention, with a gnarly old tree this far outweighs their timber value. Through groups such as private land owners and the National Trust, more steps are being taken to protect ancient Oaks and also create more broadleaf forests than ever before.
The timber
- Weight (cubic metre at 12% MC): Heavy 720kg
- Durability: Naturally durable, classified as Durable
- Treatability: Level 4, good.
- Cost: Expensive, and so it should be!
We try to get as many building components out of any Oak we get in as that is what it’s best use is and what will encourage its re-planting. There are 450 year old Oak beams still holding up St Pauls Cathedral, that's a sustainable building product! We cut posts, beams and cladding from green oak for framing and construction, we have stock sizes but mostly cut from lists sent in by our customers.
We turn the 'off cuts' from this process into furniture and craft blanks, we especially look out for burrs for wood turners. Once dry, Oak is difficult to work, being very hard on tools, and it is also probably the most difficult UK hardwood to dry successfully but pieces made from Oak are beautiful and will last forever. Green Oak will move and crack as it dries, this is character in a timber frame but a pain in the a**e if you are turning a bowl. We suggest rough turning air dried or green Oak then re-sealing the blank for further drying before finishing. Don't expect it to remain a perfect circle! We are working on a new method to improve drying Oak that is over 120mm in thickness, an age old problem, keep an eye out for updates via Facebook and the newsletter.
When quarter sawn (cut at 90 degrees to the growth rings) Oak displays its spectacular medullary rays. The image below is a live edge Oak bar top we made for a customer, the rays are the lighter flecks you see in the grain. Once it was planed and sanded it was even more spectacular.
Oak for firewood and fuel
The last cuts and small branches are processed into excellent firewood logs, Oak is the coal of firewoods and if mixed with Birch or another easy burning wood will keep your fire hot all night. Although too dense for kindling, we make the smaller firewood cuts into mini pizza oven logs, chips and smoking chunks for pizza ovens and smokers. Anything left that’s big enough goes in the charcoal kiln to make probably the best charcoal we do. Oak is one of the most widely used species for cooking and smoking, ideal for all BBQ meat and fish.
We also recycle Oak whisky casks. You need to be careful using whisky casks as they are normally around 35% moisture in the middle, even when they test ok on the edges. We kiln dry the staves then feed them into the system at the cooking log stage so they make excellent pizza oven logs, hot smoking chunks and cold smoking fine shavings. All these products smell amazing. If we spot a good solid stave we will clean it up and you will find these in the craft section of our shop as well.
Whole tree recovery
As with all our species, the slivers and bits go into the kiln as fuel for drying and pyrolisation into biochar, the leaves, bark and tiny branches into mulch and woodchip that we either give away or screen and sell in bags. Oak bark from a mature tree can be several inches thick and makes really really nice decorative chipped bark, when available you will find this in our shop.
The image below is a massive, almost 2m wide, Oak slab from a tree removal 247 Tree Surgery did in Colinton. The tree was towards the end of its life due to decay with multiple defects and was dropping large branches. It was also looming above several houses so Edinburgh council decided it should be removed. A shame it had to be felled of course, but we have made use of every part of this magnificent 350 year old tree. In fact we still have some of the slabs as they won't fit in the kiln!
