The latest annual update in our trial of a number of species planted specifically for firewood. All species are on the same soil type so whilst not particularly scientific the findings are sufficient to judge which performs best for us.
Storming ahead in both rate of growth and quality of logs is the Eucalyptus Omeo. A very hardy variety which has incredible growth leaving everything else well behind. It is incredible to think this was a tiny seed in a packet four years ago.
The Eucalyptus Gunnii is not far behind. Gunnii is a popular UK garden tree, not as hardy as the Omeo but easily and cheaply sourced.
The hybrid willow would be next in rate of growth. This would be commercially harvested every 3 years as chip for biomass boilers but we wanted to see, if left, would it make decent logs. What we have found is that as the regrowth gets bigger, the stool struggles to support the weight and splits. For more detail please see the August update on the 2017 post
The same hybrid willow in its third year is perfect for making wood chunks and so it is likely that this will be the optimum time to harvest. Willow wood chunks really do make a for good biomass when dry. Fantastic for use in log boilers, good for the first load in a wood burner and the perfect fuel for pizza ovens where the gases flare off quickly and leave a wall of very hot charcoal that can be moved around easily.
We have some older Alder plants that we grew from seed but to keep up with demand for our Alder wood chunks (used primarily by local Polish and Latvian migrants for smoking meats and cheeses) we planted an acre of Alder in spring 2014 as 40cm bare rooted saplings.
Lastly and for reference the sycamore which was planted out from pots in the same year that the Eucalyptus seed arrived is doing will but just shows how far behind it is in terms of growth rate.
Our annual update on the progress of our firewood growing trials. All have made very good progress but the Eucalyptus seems to be doing the best at the year 3 point. The hybrid willow would normally be harvested now and it is a perfect size for making wood chunks.
I’m beginning to notice quite a few of the ‘year 4’ hybrid willow starting to fail at the stool union with branches starting to ‘lie down’ in just the same way as mature willow trees often do. This was not anticipated (there haven’t been any storms or strong winds) but it does perhaps explain why ‘year 3’ is the target for harvesting commercial hybrid willow plantations for biomass woodchip. The purpose of this trial plot was to extend the cycle to six years to see if firewood logs could be produced.
The fallen branches have been harvested and the stools have been tidied up; all with a very old and dull Silky. It was noted that some of the remaining branches are now getting beyond tackling with a handsaw and will require the chainsaw.
Not a bad haul from just half of one stool but I am beginning to think that the ideal point may well be at the the three year point when everything can be cut with a silky and sent straight through the branch logger for wood chunks. (Once thoroughly dried out, willow wood chunks make exceptional ‘charcoal’ fuel for wood fired pizza ovens).
The pollarded ash is looking good with the regrowth just 1.5 years old. These trees were pollarded rather than coppiced as they are there to provide a canopy over where free range hens roam, giving them some shelter and protection from aerial predators.
Many years ago we abandoned the idea of being able to own our own woodland as there is so little of it in West Lancashire in the first place and, of that, it is very rare that it comes up for sale.
But, rather than admit defeat, we bought some arable land and field by field planted our own energy crop; species that thrived on rotational coppicing. In the first instance this was predominantly ash which we grew on from seeds collected from some fine local specimens. As the dreaded ‘ash dieback’ or Chalara dieback of ash (Hymenoscyphus fraxineus) to give it it’s proper title, gained a foothold in the UK we thought it pretty pointless in planting any more ash and started growing a wider mix of species such as willow, alder and sycamore. We also trialled a few eucalyptus varieties (from seed) to see how they compared to the vigorous growth of the hybrid willows.
Many claims about the fast growth of hybrid willow exist on the internet and we really wanted to test them out for ourselves. Having grown some willow stools as breeding stock for new cuttings we knocked them back and vowed to document the progress each year up until they made useable logs.
I will keep this post updated annually with progress.
We have quite a few young ash trees which we grew from seed gathered from local trees and planted out around 8 years ago. Whilst the vast majority of our ash trees are being grown to coppice, we have some that are under grazed by free range chickens.
Pollarding trees is a bit out of vogue but we decided to give it a go with these trees to allow us free access between the stems but still provide a good canopy for the benefit of the hens.
Research suggested that we were now at the optimum diameter to initiate a pollard and create a ‘knuckle’ from which future growth will occur.
From BS 3998:
If pollarding is to be carried out, it should preferably start soon after the tree has become established and is between 25 mm to 50 mm in diameter at the selected height of pollarding (often 2 m to 3 m). The initial pollarding cut should be made at a height which reflects site usage but which, if possible, allows some of the pre-existing foliage to be retained, in order to maintain physiological function and thus reduce the probability of dieback or death. If the tree divides into a number of stems or branches below a height of 3 m, these should be individually cut so as to initiate a “candelabra” framework.
If the stem has attained a diameter of more than 50 mm, but less than about 200 mm at 2 m to 3 m height, pollarding may still be initiated. The tree should be cut at or near the same height as a younger tree, but extra care should be taken to retain some existing branches. Larger trees should not normally be treated in this way (see Annex C for severe cutting for special purposes).
Once initiated, a pollard should be maintained by cutting the new branches on a cyclical basis. The frequency of the cycle should be decided according to site management objectives, species, age, condition and/or any product that might be required. Selective cutting, whereby some of the pollard branches are retained within each cycle, should be chosen if this would help to prevent dieback and decay in the stem.
Branches that grow after pollarding should normally be cut at their bases in order to encourage the formation of a knuckle after a number of cycles. If, however, the pollard cycle has been allowed to lapse over many years, the crown should instead be reduced (see 7.7) to the minimum necessary to fulfil current objectives. These could include the relief of any mechanical stress that would otherwise be likely to cause the stem to split apart. Even if the stress on an old pollard branch is severe, it should not be cut back to the knuckle, since the removal of all its attached foliage would probably lead to physiological dysfunction and decay. It should instead be shortened by cutting just above a suitable lateral branch [see Figure 2, R(c)], or failing that, by retaining a live stub from which new shoots could grow.
If crown reduction would be insufficient to safeguard those branches that are most likely to fail, they may be reduced to stubs in one operation (a “pole thin”), while the remaining branches are shortened so as to retain enough of the leaf-bearing twig structure to sustain the tree.
NOTE Retention of live stubs on lapsed pollards will often help to reduce the risk of serious dysfunction and hence decay and weakness developing below the knuckles.
Using just a trusty Silky Zubat hand saw it didn’t take long to do the deed. We still have no signs of the inevitable Ash Dieback disease so hopefully we will see the new growth get established over the next few years.
All material recovered from the hen pen will be utilised. The brash will be chipped for use in log boilers and the larger logs used for craft projects, replacement tool handles or sawn up and sold as firewood for log burners.
For some years now we have been growing a variety of traditional basket making willow for use as wreath bases, twig wreaths and wreath decorations with any leftovers and offcuts being used as fuel for use in wood boilers. Nothing at all goes to waste.
We spotted a number of websites proclaiming hybrid willow and poplar to be a rapid source of wood fuel with some astounding claims on the potential harvest so we decided to conduct our own trial.
We to try a commercial hybrid willow which is planted as Short Rotation Coppice (SRC) for biomass production. It has taken about 6 years to get enough plants propagated to establish a meaningful crop on the different soil types around the place and whilst there will be a another couple of years needed to complete the planting plan, the initial plants are now in production phase. The first patch is now into its third year of growth so if it was to be used for biomass it would be harvested this coming winter.
The stems are long and straight with the average diameter being around 50mm at 1m height. If harvested this winter and left to season, the crop would already be ideal for use as wood boiler and wood fired pizza oven fuel but we intend to leave this until at least 6 years to see if the firewood logs claimed by the sellers of the hybrid plants are attained and produced in any quantity.
The photo below is of a row of established SRC willow which was harvested in February 2015. The 5 months of growth is now at a height of around 2.5 meters (8ft),
Our processed willow is sold through a variety of channels depending on what it is made into: