Coppicing...

Above: Stands of coppiced trees.

We have planted evergreen Alders along the length of the brook. These little foot tall sticks over the past 3 years have grown into 10m tall, bushy trees. Evergreen Alder - Alnus acuminate (aka jorullensis or Mexican / Andean Alder) is a quick growing tree. It grows 25 m tall in 10 years, then slows to grow to a maximum height of 30m. 

Above: One of the Alders along our brook.

We chose it as it is almost evergreen in milder climates such as Willowbrook's (being only deciduous for 3 months a year, loosing it’s leaves in very late autumn and gaining them again in very early spring, as opposed to European Alder (Alnus glutinosa), which is bare for 6 months of the year).

Alders grow to 30 metres under natural conditions, which would be far taller than we would want along our brook. We have a tall stand of trees on the adjacent estate, and so to have a tiered view we would like our trees to be shorter than those, but taller than the trees in front making up the backdrop for the bell lawn, which will be trimmed at about 10 feet tall (3 metres). Therefore we want our Alders to only grow to about 30 feet tall (9 metres). Trimming them perpetually at this height would be technically difficult and would require trimming twice yearly given how quickly they grow. It would also give them an unnatural hedged appearance, which is not the look we wish to achieve along the brook, which we would like to look like a natural waterway. Thus we have decided to coppice them. 

Coppicing is a fairly ancient technique for maintaining healthy forests as well as being able to harvest firewood and poles for use.

Usually it would take alders 3 years to  bounce back after being coppiced, but our soil is so fertile we have found 18 months to be the norm for most trees. We have had several trees struck down from winds, but have left the stumps in situ and they have grown back to be the same height and density as the other trees of the same species which were not blown down, and it has only taken them 12-18 months to do this! This is because their root structure is intact, so they have plenty of water and nutrients to draw from and they put all their energy into growing their canopies again. The stump left behind after coppicing is traditionally referred to as ‘the stool’

Above: A newly coppiced stool of Alder.

Below: The same stool 18 months later.

Alnus acuminata has a good root structure suitable for suring up slopes and eroded or deforested areas. Like most species of Alder, it is found near waterways and wet lands. The wood burns well - a good even burning firewood - which is good given we have 7 open hearth fires to fuel (our planting of thousands of trees on the estate over the last 7 years far out strips any negative effects of our carbon footprint). Its freshly harvested poles are also useful in gardening and agriculture as posts and stakes. In Costa Rica the wood, with its straight grain, fine texture and reddish brown colour, is considered too good for firewood and is used for boxes and furniture. It coppices well (better than Alnus glutinosa – European Alder). 

Although they are not legumes, they do have root nodules which are nitrogen fixing (convert nitrogen in the air into ammonium for storage, thus enhancing soil fertility and promoting good undergrowth of flora below their canopies.

I would not go as far as to say coppicing is a lost art, but it is certainly less common than it once was.

Coppicing was known in the Neolithic times – the coppiced shoots, being characteristically curved at the base where they grow out from the side of the stool, have been identified in pre-historic archaeological sites). In particular there was a good find of coppiced lime in Sweet Track Sommerset which dates back to about 3800 BC. The thin poles were used for fencing, walking sticks, thatching, hedge laying and faggots (bundles of brushwood for fires).

Coppicing was common practice with alders, willows, beech, hazel, poplar and ash. Typically a woodland would be harvested in coups – small areas - at a time, so that perhaps over a 3-5 year period (depending on the species being coppiced). This would provide sustainable forestry as well as allow light into the forest to promote growth of the forest floor flora.

Brambles often grow around the coppiced stools allowing insects and small mammals refuge, encouraging biodiversity. Creating glades in the middle of a wood by coppicing a group of trees provides the open space required for many animals such as butterflies to thrive. There are far fewer butterflies now than there were at the turn of last century, so I think we should do every little thing to promote their well being. Don't even get me started on the plight of the honey bee...

Coppicing also maintains the vigour of the tree (trees that are coppiced regularly will live longer than those which are not – virtually forever - as they have no old growth and when you coppice them the weakest part of the root system will usually die back naturally to balance the growth of the canopy above).

  

One can also use the practice of singling to allow one shoot to grow on. So after the first coppicing, where you leave behind essentially only one trunk, you then get several shoots coming out of it. You would harvest all of those shoots when they are ready, except one which you allow to grow on to be a proper tree again.

I think our trees will be due for their first coppicing next winter (16 months time). We will take some before, during and after photos to share I am sure.