Tuesday 9 November 2010

Small scale short rotation coppicing

Short Rotation Coppice (SRC) is trees or other plants  grown as an energy crop. This wood solid biomass can be used in our woodburners. SRC uses high yield varieties of poplar and willow. Poplar is generally planted for visual variation rather than being a commercial crop. However as Erik who runs the B&B with his wife Nikki grew up in the Dutch ‘Populierenlaan’ or ‘Polar Lane’ in an Amsterdam suburb, poplar is a choice of fire wood with an emotional connection. Species are selected for their acceptance of varying climate and soil conditions.   
SRC can be planted on a wide range of soil types from heavy clay to sand including land reclaimed from gravel extraction and colliery spoil. Saplings are left to grow for a year and then coppiced. The first three years are part of the establishment phase and do not yield much dry matter.
After four years the trees will be ready for harvest. Harvests take place on a two to five year cycle, shorter for willow and longer for poplar, and are carried out in winter after leaf fall when the soil is frozen. The established root system and the nutrients stored in the roots and stumps guarantee vigorous growth for the shoots. The trees can be harvested for up to thirty years before needing to be replanted.
SRC has a low greenhouse gas impact as any carbon dioxide released in power generation will have been sequestered by the plantation over just a few years.
Biomass crops such as SRC willow show higher levels of biodiversity in comparison with intensive arable and grassland crops. SRC has a higher water consumption than agricultural crops. As most of our willows and poplars are planted at the lower end of our garden, where it is very boggy, they help with soil conditioning and drainage as well.
To be fair we do not want to give the impression we have a massive plantation – all we grow is some 15 willow trees and 10 poplar trees. They will not produce sufficient wood to keep both our wood burners supplied – but it is a start! The remainder of our fire wood comes from other areas of our garden and we will buy in a quantity of cordwood from a local tree surgeon as well. This cordwood will be processed by ourselves, using a chainsaw and a splitting maul. And good old-fashioned hard labour.




The willows are taken as cuttings from our beautifull mature willow, and the poplars have been purchased from Bowhayes Trees, Ottery St. Mary, Devon. 

Friday 5 November 2010

Saving energy costs with a woodburner

We have had some independent energy advise from a local Charity, Vision21. The various suggestions made and questions raised made us look again at a planned investment in new technology (An Air Source Heat pump) - see the previous post.
It actually made a lot of sense to go back to basics and utilise our (free) supply of fire wood from our garden for space heating, replacing a fire place (80% of energy produced  lost through the chimney) with a woodburner (Only 20% of energy produced is lost through the chimney).
With other words: A woodburner is a very efficient space heater and adds atmosphere and a focal point to our living spaces. We choose a 'Westfire Unique 26' for our Family Room - it looks great and throws out a massive amount of heat. Later this year we will replace an open fire in a small sitting room with an inset woodburner.
In a next post we will go into more detail about producing fire wood, the ins and outs of logging at home, short rotation cropping, types of wood that are suitable, and what tools are required.