Long Term Project - Oak woodland deadwood

Deadwood terminology 

I live in an area of Britain that has a relatively high coverage of woodland and the Forest of Dean is renowned for its historic production of oak timber. I was curious to know what happens to oak deadwood, something happens otherwise the woods would be choked with deadwood. So back in 2006 I compiled a list of 5 desirable oak deadwood subjects each one underpinned by a compelling narrative. In hindsight it looks very much like a wish list compiled by someone completely ignorant of reality. Which is why this post is more of an update than anything approaching a coherent body of work.

A wind blown oak readjusting growth to its horizontal position

No 1 of the Oak Woodland Deadwood list was a photogenic native mature tree snapped by a storm that would provide a pollarded trunk to regenerate from and a wind thrown crown to decay.  Mature oak trees, at least in the woodlands I visit, appear to require winds associated with a major significant storm event to snap a mature tree. That major significant storm event has yet to happen, so what actually happens is that the trees are blown over and more often than not, enough root system remains in the ground to keep the tree alive.

A storm damaged native tree ~ Ballochbuie Forest, May 2014

A mere 8 years after writing that I finally chanced upon a group of storm snapped mature native trees: Scot's pines in Ballochbuie forest in Scotland after a particularly stormy winter 2013/2014. One damaged tree trunk had a single remaining trunk branch that may be enough to sustain the the tree, in which case it might grow into a pollard or it may die, a future visit will confirm its fate

Harvested oak, Forest of Dean ~ March 2007

No 2 on the wishlist were the stumps and brashwood left from a harvesting operation. Fortune played its part as in March 2007 oak timber was harvested from one area of the Forest of Dean and the branches left for biodiversity, a decade on the twigs and smaller diameter branches have decayed, the larger diameter branches are still 'firm' to touch. Browsing herbivores eventually killed off any regrowth from the tree stumps and aside from colonisation by bryophytes there's no dramatic evidence of decomposition of the oak stumps. I subsequently learnt that oak stumps take up to a century to rot down and wild boar will expend no little energy in uprooting a sizeable oak stump in the quest for an as yet unknown desirable foodstuff, that I am guessing might be truffles. Making a photographing record of an oak tree stump decomposing has been abandoned.

Oak branches from March 2007 harvesting operation showing Class 2 and 3 decomposition stages ~ October 2016

Hopes of photographing a branch in situ in open access woodland have been dashed by the fallen wood being moved to build shelters, bike jumps, disappeared (perhaps sawn up for firewood?) or moved by some unknown agency for some unknown purpose (wild boar rooting around?).  So instead there has been a record made of fungi that have appeared on the 2007 harvesting debris.

Pluteaceae fungi on March 2007 felled oak branch~ December 2016

No 3 A snag or standing dead tree with a narrative. That narrative has proved elusive mostly due to my ignorance of pathogens or able to confidently assign a cause of death.  Nonetheless the 2006 heatwave might be a contributory factor for the oak mortality on the heavy clay soils. I have also discovered that a dead tree anywhere near power lines, telephone lines, public road, forestry track, cycle track, footpath path or in any location with a conceivable chance of falling on someone would be cut down for health and safety reasons. The snag really needs to be in a remote location or a nature reserve.

Stage 4 decay - loose bark on an oak snag.  

I can say with some confidence that an oak snag can stand for a surprising number of years before falling.

Decay Class 5 oak snag October 2007 it finally fell winter 2013/14

No 4 was for a naturally shed branch. Having learnt the lessons of well managed open access woodland, suitable subjects were searched for in less visited woodlands and nature reserves. Tŷ Canol National Nature Reserve provided the desired subject matter.  I have no idea when the branch fell, but when I first photographed it was class 3 decomposition and in 7 years it doesn't appear to have changed much.

April 2010 

October 2011

March 2015

May 2017

No 5 on the wish list was a dead branch still attached to a living tree. If an oak branch takes a long time to decompose on the ground then a dead branch takes a much longer time to decay away from the ground. One section of branch that died in 2010 there was still some bark attached in Nov 2014. The dead branch was still attached in autumn 2017.

Dead branch ~ November 2014 

At the time it seemed like a good idea, photograph some fallen oak trees, tree stumps and branches then return every so often to record the stages of decay as they unfolded. It's been an interesting journey so far and the oak deadwood project is probably 2/3 way through after 12 years. The management regime of woodland is soon determined by the presence of standing and lying deadwood.

Deadwood in oak woodland ~ December 2013

The importance of deadwood as a habitat resource continues to surprise:

Brussels, 5 March 2018 (IUCN) – Almost a fifth (18%) of European saproxylic beetles assessed so far are at risk of extinction due to ongoing decline in large veteran trees across Europe, a new IUCN report has found.

Due to their dependence on dead or decaying wood, the loss of trees across Europe is the main driver of decline in saproxylic beetle populations. Loss of ancient and veteran trees, tree age structure gaps, degraded landscapes that are unfriendly to tree growth, and indiscriminate felling for spurious health and safety reasons all contribute to the loss and degradation of suitable saproxylic beetle habitat. 

Saproxylic beetles depend on dead and decaying wood for at least part of their lifecycle, and are involved in decomposition processes and the recycling of nutrients in natural ecosystems. They also provide an important food source for birds and mammals, and some species are even involved in pollination.