Life in the time of Chalara

IT was June 2016 when we first saw a few blackened leaves on ash regen in a small area of the wood we were working in. I brought it to the attention of the estate’s head forester, who took photos and made notes. It was decided it was probably damage caused by deer, of which there are many in the estate’s valleys that are heavily stocked with ash, beech, oak and sycamore. We completed our thinning work and moved on to our winter felling on another estate off to the west, where we worked through large blocks of pine and larch.

In the spring of 2017, we returned to fell ash for the estate’s firewood business, as we had for the last decade or so. Just before we left our winter softwood work, the County skidder I have owned for more than 20 years decided it was going to strip the splines on a gearbox shaft, which required it to be towed back to the yard for repairs. It was while I was steering the stricken tractor that I saw the first evidence of ash dieback. During a break in the rescue mission, I took to the bushes at the side of the ride for a ‘comfort break’, when I found myself looking at a small ash sapling that was green until about halfway up, where it suddenly turned a dusty chocolate brown. This, I realised, was Chalara.

Ash dieback on annual growth.

I snipped out a piece of stem that included the change of colour, after taking some decent pictures with my phone. I spent the next couple of evenings researching Chalara and I had some long internet conversations with an old girlfriend who long ago settled in Denmark, owning a stud farm where they have seen Chalara decimate their ash trees. It confirmed to my own satisfaction that what I had seen was undoubtedly Chalara.

The first thing I did, on my return to the estate, was ask the head forester if he’d found any more evidence of Chalara in the woods where we’d worked the previous year. He had identified some ash saplings that he was suspicious of and so we took a brief ride to the wood where he had seen what he thought might be Chalara. It wasn’t. He asked me how I knew it wasn’t and I used the phrase that was to become widely used over the next couple of years: “Once you’ve seen Chalara you don’t mistake it for anything else.”

Clear illustration that the disease is still spreading aggressively.

We went back to the office and spent a couple of hours poring over felling licences, risk assessments, insurance documents and contracts before I left to start moving machines onto site for the summer.

I took a long, slow drive along the forest tracks with the windows of my pickup rolled down and was almost back to the forester’s house when I spotted it. On a piece of landslip above the road, at the opposite side of the valley, were hundreds of self-sown ash saplings standing together, almost like a field of corn. And there, right on the roadside, was one stem that turned from green to brown about four feet from the ground. I got out, climbed up the bank, and within ten minutes I had enough dead ash saplings to make a decent besom.

I walked into the forester’s office with a handful of sticks that would change the way we had worked the estate for over 20 years. The threat of P Ramorum in the larch woods had not really proved the major problem we’d been expecting, but Chalara looked to be a different animal. It hadn’t lurked threateningly on the edge of the Pennines for 10 years. It had knocked briefly on the door, then barged in. The way it has marched through the woods since those few dead leaves we spotted in the summer of 2016 has been hard to believe.

I’ve had a lifetime in forestry and I’ve become used to seeing things progress at a snail’s pace. I did the first thinning in Oscar Park back in 1987 and we’re going back in to give it a final thin in 2020. I wrote a series of articles many years ago in FJ that included one called ‘The Oscar Park Gang’. That wood has gone from first to final thin, and it would be clear-fell but for the conversion to a CCF plan put in place by the last forester. All this is in parallel with my career in contracting – that’s some timescale. Chalara is going to take the ash woods on Yorkshire estates from first thinning to clearfell in two, maybe three years. It really is that aggressive.

What we saw that summer, as time progressed, was lots of small saplings dying off from about halfway up, some larger regen losing one side of the growing crown, or maybe just a random branch.

Dead ash standing next to a perfectly healthy live neighbour.

In 2017, we thinned a large block of sycamore that had a few ash trees mixed in. We didn’t find much evidence of ash dieback, as it was being called by then. We had almost finished thinning the sycamore when the forester decided he didn’t have enough timber to fill the growing demands of the firewood business, so we would move along the valley and thin some more mixed woodland.

This next patch contained a mix of sycamore, birch, ash and a few alder. The ash looked fine and we felled quite a few without any signs of disease, but just as we were about to wrap the job up, we came across a large old ash in one of the medieval stone quarries that are abundant in the area. This ash was very cankered. It had already shed a few large branches and was hollow, so we were asked to take it down due to safety concerns.

It’s always interesting when these big spreading trees hit the ground. I’ve felled hundreds of them, but this one didn’t ring true when it went down. It shed every piece of branch that was thinner than my wrist. It looked as though someone had gone over it and removed all the small branches with a pair of secateurs. It was the strangest thing I’d seen in many years. When we walked over the site, it was clear that all the small branches had simply shattered when they hit the ground. This was despite the tree apparently being in full leaf. This brittleness in the small branches became something unremarkable by the time we came to felling the annual firewood harvest in 2018.

The Timberjack 1270 in diseased ash.

Humphry Repton had landscaped the estate a couple of centuries ago, but some of his plans were never completed. His basic theory of landscape woodland was that small, strategically planted woods could be carefully placed so they appeared to fill the landscape. They didn’t, they just looked as though they did, from a fixed vantage point. This was usually the ‘big house’, and so it was here. Some pieces of the puzzle had been missing, so the current lord had farmland planted with these strategically placed woods to finish what Repton started.

Unfortunately, much of what was planted in these enclosures was ash and once Chalara appeared it ran riot. In two growing seasons it has killed all the ash in these new plantings.

Back in the mid 1990s, around the time I started working on the estate, several extensive landscape plantings were completed. These were around 10 hectares, each mainly of Scots pine as a nurse crop, with a hardwood mix of ash and oak. The plan was to eventually have oak woodland with a smattering of ash and the occasional mature pine. This is real, long-term forestry planning. Now, the pine and oak are doing fine, but the ash is just about a total loss. A halo thinning around the oak and ash was quickly modified to just thinning around the oak. We will be going in with a harvester next year to line thin the pine and remove the dead ash.

This is the most advanced case we’ve yet seen, but we expect to see more like this next spring.

It is everywhere in North Yorkshire. Riding around the local roads, we have started a new family game. Gone is the annoying kid’s game of ‘spot the Mini’ (which involves being punched on the arm with a cry of “mini punch, no return”) and the ‘spot a yellow car game’ which isn’t difficult now yellow cars are back in fashion, or the old favourite ‘I spy’. The new game is called ‘spot the live ash tree’. Not much of a game, really, and I expect it to be even less so next summer.

There are various theories as to how Chalara entered the UK. It blew in on the wind, it was carried here by migrating birds, it’s always been here but the conditions weren’t right, or it’s a new mutation that suddenly became virulent.

I was given a very plausible explanation, which I felt was more of an admission, by someone who works for a large body involved in forestry.

Batches of seed from UK ash trees were sent abroad, to an EU country, where it was germinated and grown on in nurseries. The whips that were re-imported were distributed and planted throughout the UK and it was these new plantings where Chalara first appeared.

I don’t want to get into a debate on the mechanisms used here, but sending seed to a country where Chalara had been identified and then accepting the seedlings back for planting seems reckless in the extreme.

The tail end of that 2018 felling season was marked by the realisation that the brittle branch issue we’d seen the year before wasn’t only something to be noted. It quickly became obvious that felling trees from within a tight crop was fraught with dangers.

Live trees next to dead ones.

It wasn’t only when the trees hit the ground that branches were dislodged. There was a moment when each tree went down when even fairly big branches would snap off and fall to the ground or, even worse, hang up in the adjacent standing trees. It was obvious that we would have to look at using a different felling method. The use of hand cutting as the primary method of taking out diseased ash was no longer practical. The safety concerns were just too great.

The answer, then, was to take out everything that we could with the harvester. Felling all the smaller trees from within the crop had the effect of dislodging a good percentage of the dangerous branches from the larger trees we had to leave, as they were too big for the machine to handle. It wasn’t an ideal situation, but it at least made room to fell the remaining trees and it cut down on the time we spent on the ground with chainsaws.

One thing it did do, for sure, was to remove any hint of complacency. I’d had 30-plus years of felling, many of those years in hardwood, and the other guys cutting with me had more than 20 years, with one of them more than 40 years. Even so, we all recognised this was something new. We had all felled the occasional tree that had us spooked, but this was different. It was almost every tree that made us stop and think. I instructed everyone that we had to treat each tree as if it could be the one that left someone needing an ambulance. I’m still in no doubt that it was this attitude that saw us through the summer without anyone getting injured.

Chalara is like an extra-marital affair. Once it’s done, it can’t be undone. It might be forgiven, but it’ll never be forgotten. It might take many generations before ash recovers to again be a major landscape tree, but I for one don’t hold out much hope that I’ll see big roadside ash up and down the lanes here in my home county. I don’t hold out much hope that my kids will see it either, but maybe their children will.

I’m sure the blame for the demise of the ash tree as the queen of the woods will be firmly laid at the door of our generation, though. Whether it’ll go down in history as reckless management or just pure bad luck, we’ll have to wait and see.