Woodland Carbon Code verification on the Isle of Arran: a field visit to Sliddery Shore

Travelling to Arran felt like stepping into a different world. The ferry ride across the Firth of Clyde was a little bit rough, yet I couldn’t help but smile at the people braving the windy sea air outside, and before long I found myself joining them. By the time we reached the island, the first glimpses of the coastline and the rising Goatfell already promised a unique experience.

The purpose of the trip to Arran was for a Woodland Carbon Code year 5 Verification survey for the Sliddery Shore project. Verification is an important milestone in the lifetime of a Woodland Carbon Code project and forms part of the ongoing monitoring that ensures the woodland is establishing as planned. In practice, the Verification process involves walking the site, measuring tree density at specific sample plots, checking species health, and noting any natural regeneration, browsing impacts, or any other site observations that may influence how the woodland develops.

Conducting a survey that required a ferry crossing brought its own layer of unpredictability. Bad weather the day before reshuffled my original travel plans, forcing a change to both route and departure time. With these alterations meaning I had a tighter window to reach Sliddery Shore and conduct the survey, preparation became even more important. Before heading out to site we always complete a site-specific risk assessment, and in this case clear communication with the team and landowners became even more essential to keep everyone updated on arrival times. It also meant double-checking every piece of equipment was packed and ready to go so no time was lost once I arrived on site. As always, I was also carrying one of our GPS trackers - a small but reassuring safety measure that lets colleagues follow our progress from the warmth of the office, particularly useful on more remote sites. Fortunately, the time buffer I’d built into my original plan allowed the delays to be absorbed and ensured the Verification could go ahead smoothly.

If you’d like to see what a Woodland Carbon Code Verification visit looks like in practice, check out our verification video on the Quality Assurance page.

What makes this project particularly interesting is its scale. At 1.89 hectares, it is far smaller than the typical Woodland Carbon Code project – with average project sizes sitting at around 74 hectares in Scotland and 13 hectares in England(1). Previously, ‘small woods’ under the WCC were considered projects of up to 5 hectares, but under the latest version of the Code, version 3 released in August 2025, this threshold has been extended to 10 hectares. This change opens up options for smaller projects to use the Small Woods calculator to move through the certification process, though it is not a requirement. Smaller scale projects naturally generate fewer Pending Issuance Units than larger woodlands, which can make certification costs proportionally higher when compared with potential income which could be generated from the sale of units. The Small Woods provisions are designed to try and address this challenge. Find out more about the small woods process on the Woodland Carbon Code website.

Find out more about the process of selling carbon on our Selling Carbon page.

Visiting a smaller site gives a very different perspective compared with the larger projects I have surveyed. The smaller scale allows the site to be fully walked around, providing a complete picture of the woodland. This project, planted in 2021, has been designed to be managed on a non-intervention basis. That means nature is given space to lead: once established, the woodland will be left to develop naturally, allowing structural diversity, deadwood, and natural processes to shape its long-term character.

The site is a fully native broadleaf and Scots pine mix. This combination provides valuable diversity for the project - supporting a wide range of wildlife and creating a mix of habitat structures within the woodland. Walking the site, I could see this variety in action on a small scale. I wandered past rowan heavy with berries, oak galls tucked among the branches, and ladybirds settling into sheltered spaces between tree stems. It was also clear that the character of the island has shaped the way the woodland is developing. The sections closest to the sea show their resilience to stronger winds and salty air, adding to the uniqueness of the site and offering a visual reminder of the shelter these young trees are already beginning to provide. Even at this smaller scale, Sliddery Shore offers many benefits that come from planting native species suited to the landscape. The woodland sits on land previously used for grazing and improved grassland, meaning the shift from pasture to young native woodland already brings noticeable ecological change. This small pocket of woodland will expand local biodiversity and strengthen habitat networks across the island.

Even at just a couple of hectares, this woodland makes a tangible difference, not just for carbon capture but also for local biodiversity and enhancing the wider environment. It creates habitats, links existing woodland patches, and provides food and shelter for a range of species. There is a quiet satisfaction in seeing how a carefully planted woodland can contribute to both climate goals and the local ecosystem, especially in a place as unique as Arran. It’s a reminder that every tree planted, no matter the size of the site, plays a part in restoring landscapes, capturing carbon, and connecting people with nature.

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Sources

1. Gov.UK, Nature Markets Framework progress update 15 March 2024 https://www.gov.uk/government/publications/nature-markets-framework-progress-update-march-2024/nature-markets-framework-progress-update-march-2024