Should foresters be 'beating up' trees to age them?

ASK foresters about ‘beating up’ and they will describe an age-old practice carried out towards the end of the growing season to count and replant trees which died shortly after planting. Not only does this replenish and shore up the stand but it also allows foresters to identify and address any issues that may have affected growth and seedling tree establishment. Despite the description strongly suggesting deliverance of damage, ‘beating up’ for the forestry fraternity is very much a restorative and constructive practice. 

However, the phrase has recently taken on a whole new meaning which sounds as violent as you can get against healthy, living trees. Arborists are trying to accelerate tree ageing, by the same token causing treated trees to die earlier than they normally would. It seems a strange thing to be doing at the very time when UK forestry is crying out for more planting and constantly crying about the predicted future shortage of home-grown timber. 

However, the perps (perpetrators) claim there is method in this madness, largely based on historical considerations. But not all tree species are subject to these novel ideas. English oak is the number-one target, although I am also aware of efforts elsewhere to age common beech, albeit by more subtle, biological means as opposed to the mechanical damage visited on oak trees. No mention yet of trying to age common ash. Perhaps Chalara ash dieback disease is considered to be enough of a natural ageing treatment for native Fraxinus excelsior.

Conservationists want to accelerate the ageing of oak trees so they will look like this within an unnaturally short period of time. Pictured is King Offa’s Oak at around 1,300 years old, located in Windsor Great Park. (Image: FJ)

I was aware of this new dimension to ‘beating up’ trees and woodland, but had paid little attention until reading a newspaper report describing in detail the punishment being dished out to English oak. According to Tom Whipple writing in The Times, relatively young oak trees with just 200–300 years on the clock are being cut, slashed, torn, ground down, gouged out, hammered and hollowed out to imitate the damage caused by natural events like lightning and ice storms, and subsequent ageing. This is all done in the name of nature, as article’s title (‘Cutting-edge plan to nurture nature’) suggests.

The site of the slaughter is Sherwood Forest, due to a perceived hiatus between the forest’s legendary ‘Major Oak’, estimated at 800 to 1,000-plus years old, and the next tier of ancient oaks which max out at 500 years old. The reasoning goes as follows.

The Major Oak is still standing as an ancient oak with at least 800 years on the clock because by the 17th century the tree was already too old and gnarled to be felled for timber to make ships. 

According to the article there exists a gap of some 300–400 years between the Major Oak and the next oldest trees because those missing were used to build ships like Nelson’s HMS Victory during the heyday of Britain’s maritime success. The next tier of veteran oaks with 400–500 years under the belt is fairly well represented because these trees were saved by the advent of ironclad ships in the early part of the 19th century. 

It’s clearly not as simple as this, because the Sherwood Forest website says its collection comprises around 1,000 native sessile and pedunculate oaks and their hybrids, many in excess of 500 years old – old enough by most people’s expectations and standards. But clearly not old enough for the conservation brains behind this project, who want more oaks with a canopy form and structural profile closer to the Major Oak with its 800–1,000-year history. They see new life in the near death of oak trees which tend to support a wider and rarer range of arthropods and microbes encouraged by the tree-ageing process. And in the absence of Doctor Who or Back to the Future, the only thing they can do to maintain this range of biodiversity is to try and speed up the ageing process by beating up the trees to make a 250-year-old oak look and behave like an 800-year-old oak in form, structure and physiology, thus plugging the perceived gap in the population of oak trees with more than half a millennium on the clock.

• READ MORE: I nearly died from diseased ash. Then the HSE inspectors came.

So what’s going on and who is doing what to oak trees in the leafy glades of Sherwood Forest? Urban Forestry (Bury St Edmunds), East Midlands Ecology Consultants and an RSPB contractor in charge of beating up the trees are actively involved in the project. The following is a selection of the treatments they’ve been dishing out to trees (clearly not for the faint-hearted).

• Winches used to tear the tops off of trees to simulate damage caused by an ice storm
• Chainsaws used to scar the bark right down the side of a tree to simulate lightning damage
• Hammering the trunks to imitate impact by the hooves of large mammalian herbivores
• Chainsaws used to gouge out hollows in the tree.

Depending how you view it, physical damage to otherwise intact and healthy trees to accelerate decay and rotting of the bark could be regarded as a positive thing, although others may regard the whole enterprise as ‘barking mad’. 

As a plant pathologist and applied entomologist who spent much of his time in the field urging workforces not to damage tropical tree crops like rubber, citrus, mango, cocoa, avocado and the rest, I clearly have my reservations. Unnecessary mechanical damage to trees increases susceptibility to infection by primary plant pathogens while offering entry points for invasion by secondary invading bark-boring beetles and other insect pests. This would subsequently cause immediate death and so defeat the whole object. I can’t help but be concerned for oak trees in the wider concept and arena. 

English oak is already suffering from major decline, with much thought to be environmentally inspired by new housing, road and industrial developments with accompanying disturbance of soil and water relations; and by a more recent biologically based phenomenon called acute oak decline, which features plant pathogenic bacteria and bark-boring beetles. 

Oak trees are dying at a frightening rate from these and other problems, not to mention the alarming number of veteran oaks succumbing to the chainsaw because they are in the way of projects like HS2. Then there are the oak trees accused of causing subsidence, with councils taking the cheap way out and removing the trees even if they are of ancient or veteran status. 

Significant numbers of mature English oak trees (including veteran and even ancient specimens) located in urban and suburban areas come under threat each year, having lost their advantage as far as local authorities and others are concerned. (Image: FJ)

It’s one thing to mechanically damage trees to simulate the ageing process and thereby foster a specific range of biodiversity associated with extremely old trees in their death throes, but can you alter the tree’s chemistry, which is clearly governed by the natural ageing process?

As far as I am aware, attempts to accelerate the ageing of 80–100-year-old beech trees by inoculating the trees with basidiomycete fungi normally associated with beech trees twice that age have not proved particularly successful. Could it be that the chemistry of these younger trees is incompatible with the support of these specialised old-wood fungi? And could the same restrictions apply to the oak trees being beaten up in order to simulate ageing, thereby supporting specialised insects and microbes?

Consider some of us sceptical.