I recently spent some time in the company of a Hungarian forester, Bela Vaga, and we started talking about the difficulty of getting oak to regenerate under oak, and how to perpetuate an oak forest. He had some interesting ideas on the subject.
His ideas centred on “What is a natural oak forest?”
In much of Europe and definitely in Britain a “natural oak forest” is perceived to be a forest that is predominantly oak with perhaps a little ash and maybe some hazel understorey. In Britain we would call this ancient-semi natural. But how natural is it?
We started with some facts.
Oak trees and oak trees in forests have been around for thousands of years.
Oak trees can live for 600 to 800 years.
Oak as a species must be able to regenerate itself naturally or else it would no longer exist.
And then some conjecture.
Oak has always been important to man, as a naturally durable timber for building, for fuel, for tannin and for animal food.
From the time of stone axes man has harvested oak trees and manipulated the forests in which they grew.
With oak being the most valuable tree in the forest it is likely that even early man favoured it over other species. Manipulating the forest to increase its dominance and reducing the numbers of other species present. A trend that continues today.
Driven by the use that he put the timber to and limited by the capability of his tools the younger smaller oak trees were more valuable than the big old veterans. So as they died out they were not allowed to replace themselves and the oldest trees in the forest became 200 years old instead of 800 years.
Coppicing of both oak and hazel became important and for hundreds of years oak were grown to produce short stubby stems and big forked branches for boat building.
Now the drive is for long clean stems of white oak that can be machined to mass produce furniture.
So the oak forests we have today may be ancient but they are far from natural.
And we wonder why we can’t manage these forests with close-to-nature principles and get them to regenerate themselves naturally.
So what is a natural oak forest?
Well I now believe that a natural oak forest isn’t actually an oak forest at all, but a mixed forest with oak in it.
In a “natural oak forest” many of the oaks will live to be 600 to 800 years old and maybe even older.
Not having been selected for specific form types, the gene pool of the oaks would be much greater, allowing them to adapt more readily and regenerate in conditions where modern oaks cannot.
Many other species of tree and shrub will be present, but especially ash, alder, birch and some beech and they will probably outnumber the oak.
In the long life of these natural oak trees there will be many opportunities for successful regeneration. The oaks will see several generations of their shorter lived companions come and go, and as these trees die and decay then the conditions will be right for the oaks to colonize in their place. With the longer time scale afforded to the oaks then natural successions will have time to take place. So as in the colonization of bare land, where the pioneers of birch and Scots pine are followed by oak, then within the forest ash beech and alder would be followed by the oak.
So if this is what a real natural “oak” forest would have looked like.
Then when trying to grow oak following close-to-nature principles we must cast aside the model of our young over managed ancient semi-natural oak woods and look back in time to the real wild wood, when oak would have been one of many species growing in the rich and biodiverse forest and would have regenerated itself freely in conditions suited to its success.
Then we can work with nature instead of struggling against it.
What do you think?
Mike Seville, with thanks to Bela Varga (ProSilva Hungary).