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  • Writer's pictureThomas Pinches

Laurel control at an ancient woodland in Dartmoor

Updated: Jan 19, 2023


Shaptor is one of Dartmoor’s woodland gems. Managed by Woodland Trust it contains an incredibly diverse mix of woodland habitats and ancient woodland ground flora. These habitats are threatened by cherry laurel: an evergreen invasive species that thrives under closed-canopy woodland. Woodland Trust acquired Shaptor with a heavy burden of cherry laurel. In many areas the laurel was so dense it had shaded-out the native ground flora, including carpets of bluebells, wood anemone, dog’s mercury and yellow archangel. We were asked to produce a map of the extent of the laurel in one of the more heavily affected compartments; then to produce a plan to eradicate it.


Mapping

The compartment in question was around 6.6 hectares and was dotted with large granite boulders, outcrops and tors, making navigating the terrain tricky. I recorded the laurel using a GPS device (Garmin GPS map 65).


Across a large proportion of the site there was a light smattering of small, sapling sized laurel plants, and it was impractical to map each one (it would have produced a useless map of thousands of dots!), so I used the ‘track’ feature to map zones of high, medium and low density; I also marked any large individual plant or clusters that I came across. The resulting map is shown below. This gave an overall impression of where the worst areas were and which areas were free from laurel.



Treatment

Next came the task of eradicating the laurel. This was done in winter to avoid damage to any ground flora. In hindsight, it would have been better to do this at the end of winter rather than the beginning, as the brambles would have died back making it easier to get around, not to mention fewer pesky ticks. Because of the very large size of the compartment and the shear number of individual plants (some being only a few inches tall), we had to be systematic in our approach or else it would have felt like finding needles in a haystack.

I produced a grid layer in QGIS (Vector>research tools>create grid), where each square was 20mx20m and overlaid it onto the map of the compartment. I then used the GarminCustomMap plugin to create a .KMZ file, which I uploaded to my GPS device. This allowed me to see the 20x20m grid on my device as I was moving around the woodland. I could thoroughly check a 20x20m area, treat any plants within it, and move to the next one. I also had ‘tracks’ activated on my device, which recorded everywhere I had walked, so I could see, at a glance, where I’d been and where I still needed to go.


We went about the treatment in 2 ways: small plants (less than 6 feet) were sprayed with a knapsack sprayer, containing 5% glyphosate solution. I am super cautious when using glyphosate and try to avoid any exposure, especially inhaling the fine mist that’s produced by a knapsack. So I use a full-face mask and 3M 6059 ABEK1 filters, along with disposable nitrile gloves and coveralls, which I can whip off and throw straight in the wash.

Larger plants were either ‘stem injected’ or cut and stump treated (depending on whether the diameter of the stem was large enough to stem inject). The traditional method of stem injection is to drill a hole and fill it with herbicide. This can be time-consuming when dealing with very large amounts, so we use a chainsaw to cut into the bark at the base of the plant and spray the wounds with herbicide (20% solution). With very large diameter plants you can bore with the chainsaw and fill the hole, but in many cases it’s more akin to stump treatment, but you’re leaving the plant standing.

I always include in my quote a few extra days for follow-up treatment, where I can return around 6 months later to finish off anything that survived the initial treatment.




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