The Natural Capital of Irish Forests

Written by Owen Small

If we look back 10,000 years ago, we could follow the journey of a red squirrel scurrying the forest canopy in what is now Kerry.¹ The squirrel moves across ash and hazel in a beautiful woodland landscape that—less than two millennia prior—was buried beneath glacial ice. Remarkably, this adventurous rodent could feasibly travel all the way to the tip of what is now Co. Donegal without ever touching the ground.¹

Sessile Oak (Quercus petraea) in Killiney Hill woodlands

In stark contrast to a rich, sylvan heritage, as of 2022 the National Forest Inventory estimates only 11.6% of Ireland’s land area is forest.² A mere 808,848 hectares, this number is dwarfed by other European woodlands. In the rest of the European Union (EU), woodlands must span at least 0.5 hectares to be defined as “forested” in land cover data.³ For Ireland, our small percentage of woodland has resulted in an adjusted definition.⁵ Per the Forestry Act 2014, a minimum area of only 0.1 hectares is needed to define a “forest” in land area statistics.⁴

How could such a heavily forested island make such a drastic transition?

A few centuries following our squirrel’s journey, humans arrived, but these Mesolithic people relied on and revered their forests.¹ It wasn’t until about 6,000 years ago, when Neolithic farmers settled the island, that an era of deforestation and land transformation began.¹ Compounded by contemporary anthropogenic activity and colonialism, Ireland’s lush temperate rainforests and upland woodlands dwindled to the state we see today.

Understanding this history—and the gradual, yet severe, change this wonderful green island underwent—emphasises how essential the forests we have are. Our woodlands don’t simply provide timber. They provide a suite of ecosystem services—the various benefits, tangible and intangible, humans derive from these environments. With extreme loss of forests comes a loss of physical and societal benefits.

Beyond the cultural and ecological degradation, this lack of woodlands has also given Ireland a tremendous disadvantage in meeting EU goals under the Nature Restoration Law.⁸ Ireland’s own Forestry Strategy 2023-2030 aims to address this, explicitly highlighting key values of forests: forests for Climate, for Nature, for Wood, for People, and for Economy & Rural Development. As we move forward in this new era of legislative focus, forest owners and managers need methods to conduct valuations of their sites and forecast the benefits their woodlands provide. They’ll need tools to assist their management to not simply focus on timber productivity, but a holistic approach for optimising the value of a forest.

This is where ForES⁶, a joint research project with Trinity College Dublin and University College Dublin, enters the conversation. Leveraging natural capital accounting and statistical modelling, ForES assesses forest ecosystems and aims to provide resources to inform forest management that optimises ecosystem services centred on the values for wood, climate, nature, and people.

What is Natural Capital Accounting?

In the context of ForES, natural capital accounting (NCA) is the use of Ecosystem Accounting methods set forth by the United Nations (UN) statistical framework: System of Environmental Economic Accounting (SEEA).⁷ Despite what the second “E” in SEEA stands for, our project focuses on the intrinsic value of forests to humans, not the monetary. What are forests providing people physically, emotionally and environmentally? What ecosystem services can we derive from an environment?

In general, ecosystem accounting is applied at large scale, assessing countries or regions. The Irish Natural Capital Accounting for Sustainable Environments (INCASE) project sought to apply the framework at a catchment scale. Following suit, ForES employed a novel approach of using ecosystem accounting at site scale. Working with stakeholders in Irish forestry, ForES set out to track—at site-level—four prioritised ecosystem services: wood provisioning, climate regulation, recreation services, and nature provisioning.

Beard Lichen (Usnea subfloridana) growing in Ticknock native woodland and recreation area

On our 25 forest sites, we first developed Extent accounts, mapping what ecosystems are present, and then Condition accounts assessing the quality of those ecosystems. Both are what’s known as stock accounts. We’re now in the process of developing our Ecosystem Service accounts, or flow accounts, showing the supply of these services and their use. This stock and flow system is key to the SEEA Ecosystem Accounting framework. Determine the asset and its condition (stock) and track the use (flow) of services.

So, we have methodology to see what is present and what has been at a forest site. If accounts are robust enough, this information can forecast changes over time. But what if data is limited? What if a forester wants to adjust what services their site provides and see how different changes will impact different services? In the absence of strong, data-driven accounts, how can we look forward and inform management to optimise the ecosystem services a site provides?

Modelling for Ecosystem Services

Our ecosystem accounting methodology allows foresters to assess the history and the current status of woodlands, but data limitations and complicated technical methods limit this framework for widespread and effective use. To address this, ForES developed a predictive tool that not only overcomes the absence of reliable data but is widely applicable and usable for Irish foresters and forest managers. The tool uses a Bayesian Belief Network (BBN) model informed by expert opinion of forestry and forest ecology professionals.

In lieu of empirical data, Bayesian models can rely on probabilistic information provided by expert knowledge. When validated, these expert-informed probabilities feed a comprehensive, linear model that can return the likelihood of selected ecosystem services with the input of site characteristics and management decisions. Moreover, where the model may appear to have limitations is arguably where it can excel.

These linear BBN models lack dynamic interactions accounting for feedback loops. While this may reduce its ability to capture the complexity of forest ecosystems, it also offers greater applicability when there is less concrete information available. The idea is not to be exact, but to rather provide probabilities of potential outcomes to inform decisions—not to make the decisions, but rather support decision making. Like any tool, it requires the user to be knowledgeable; to be familiar with forestry and forest ecology in Ireland, so that it can be leveraged with site-level knowledge to assist decision-makers aiming to optimise a forest’s ecosystem services.

The ForES Decision Support Tool interface with an example input scenario and its returned output of probabilities

Applying ForES to Valuation of Irish Forests

The best practice of these tools and methods is simple: inform the user to support management decisions. Currently, our site-level ecosystem accounting methods are experimental and have only been applied to 25 selected sites. Ideally, with time, these methods will be replicated as data sources become more accessible and reliable. This could offer a robust framework for which foresters and forest managers could assess the changes to their sites over time. The ability to track a forest ecosystem, its condition, and the services it provides, can prove to be an essential tool for management as Ireland and the EU begin to incentivise nature restoration and forestry.

In conjunction with our BBN model-based decision support tool, stakeholders could then guide management to optimise the value of their forests—value beyond timber sales. The aim is a forester will see what site changes can impact say, nature provisioning services. Their ecosystem accounts show that their woodlands are largely providing timber and recreation areas, but they wish to optimise nature provisioning with minimal trade-off. ForES’s decision support tool will offer them guidance as to what management will draw the greatest optimisation for that service at a site.

Is there use beyond this? I believe so. I see ecosystem accounting as having amazing applications. With further development, these accounting methods and our model could help guide truly impactful nature restoration work, while continuing to support Irish forestry.

Just as well, I do see severe pitfalls. If inappropriately applied, natural capital accounting and the quantification of ecosystem services could lead to obscene levels of greenwashing and monetary exploitation. So often, when the word “capital” is spoken, everyone’s mind goes immediately to money. It’s understandable—it’s quite literally the definition—but this mindset overlooks what is truly important: the value of an ecosystem. It’s essential this idea isn’t lost with these tools, and that organisations are prevented from capitalising on disingenuous nature restoration focused on short-term profit over lasting changes.

Value does not start or end at the monetary worth of a person, place, or thing. It begins and ends at “worth”—innate and immaterial worth. Ecosystems, specifically forests, are worth much more than any monetary value ascribed to them. As these ecosystem services show, they provide an intangible wealth of benefits to society, and these tools—when used appropriately—can help quantify that worth for stakeholders and policymakers. That is the value of ForES: connecting human need to woodland ecosystem health for the mutual benefit of both.

If you’re interested in learning more about ForES or speaking with the project team, please feel free to reach out to us via email or social media. Our project website is here, and you can also find us on Instagram (@foresproject).

References

1. History of forestry in Ireland – Teagasc | Agriculture and Food Development Authority

2. Forestry – Ireland’s Forests – Statistics 2023 – Teagasc | Agriculture and Food Development Authority

3. Forests, forestry and logging – Statistics Explained – Eurostat

4. Forestry Act 2014

5. The European Union and forests | Fact Sheets on the European Union | European Parliament

6. Home | FOR-ES

7. Ecosystem Accounting | System of Environmental Economic Accounting

8. European Commission | Nature and biodiversity | Nature Restoration Regulation

9. Ireland’s Forest Strategy (2023 – 2030)

Author Biography

Owen Small is a research assistant and project manager with ForES at Trinity College Dublin. He comes from a background in both terrestrial ecology and water quality, holding a BSc in Biology from the University of Pittsburgh-Johnstown and an MSc in Environmental Science from University College Dublin. Throughout his career, he’s had a wealth of experience in environmental regulation, land stewardship, and habitat restoration, most notably with the U.S. National Park Service and the Pennsylvania Department of Environmental Protection. Education brought him to Ireland, but the landscape and opportunities in ecology and nature restoration have kept him here. Contact: smallo@tcd.ie.