Sustained yield key to continuity in forest management

A forester’s ideal is a forest, or group of woodlands, in which an approximately equal volume, or value, of timber can be cut every year. This is the principle of sustained yield which is one of the fundamental conceptions of continuous forest management.

– WE Hiley, Woodland Management,1954

Although sustained yield forestry wasn’t practised widely in Europe until the mid-19th century, the term was first used in 1713 by Hanns Carl von Carlowitz.

Ironically, he began his career not as a forester but as an accountant with the Royal Mining Office in the Kingdom of Saxony. He adopted the concept of sustained yield to highlight the danger of over exploitation of forests from mining and shipbuilding.

Sustained yield management averted forest decline in much of Europe from the 1850s but didn’t arrive in Ireland for almost a further century.

Sustained yield forestry has been broadened to incorporate sustainable forest management (SFM), which was defined by the UN Forum on Forests in 2007 as a forest practice that “aims to maintain and enhance the economic, social and environmental value of all types of forests, for the benefit of present and future generations”.

While sustained yield emphasises timber production – and forest profitability – it is essentially about continuity and preserving the forest’s continuum.

It should be at the heart of SFM, not at the periphery, where it has been positioned, especially since the State decreed last year that productive coniferous areas cannot exceed 65% of any area planted.

Afforestation programme

Sustained yield played no part in this ruling nor in the State’s overall policy to achieve a 50% native tree annual afforestation programme.

These decisions have ignored the role of sustained yield forestry in achieving climate change mitigation targets as outlined for afforestation and wood production in Ireland’s Climate Action Plan.

SFM endeavours to give equal weight to the forest’s economic, ecological and societal services and goods.

Social aspects of SFM such as recreation have been practised for a half century since Ireland adopted an open forest policy in the 1970s.

This public good forestry is acknowledged by members of the public and tourists who make 38 million annual visits to Irish forests – north and south.

While recreation is the most visible elements of SFM, there are other non-wood and non-revenue generation aspects of SFM, that forest owners are being asked to supply.

Putting a monetary value on sustained yield forestry is a straightforward economic exercise, but the State now needs to put a value on all elements of SFM, including carbon and ecosystem services, especially if farmers are to be attracted to a long-term land use such as forestry.

These are issues that need addressing in the mid-term review of the Forestry Programme 2023-2027 if a sustainable afforestation programme is restored.

Sustained yield forestry has to be part of this review just as it is central to Ireland’s Climate Action Plan, whose twin goals for forestry are to displace carbon-based materials in construction and energy as well as realising the forest’s role as a carbon sink.

Sustained yield forest management maintains the equilibrium between timber removed and retained so, in principle, it ensures the forest continuum.

In practice, annual forest volume increment (the annual volume increase in forest growth after natural losses) needs to equal or preferably exceed the annual timber harvest.

This approach allows for future heavy demand for timber and forest damage caused by disease, fire and windblow.

Forest management in Ireland and Europe caters for this eventuality. For example, in Ireland, average net annual volume increment between 2017 and 2022 was 10million m3 according to Ireland’s National Forest Inventory 2022.

The estimated annual harvest during this period was 5million m3, which means Ireland could harvest a further 5million m3 of timber yearly.

While some of this volume would have little value for construction and other sawn products, it could be used as biomass for energy and wood-based panel products. In Europe, an estimated 70% of the net annual increment is harvested according to State of Europe’s Forest.

Dr Pablo van der Lugt, lecturer in bio-based building at Delft University, maintains that the annual increment in Europe’s forests is 800million m3 while only 500million m3 is harvested, leaving a 300million m3 surplus.

Researchers in the Partnership for European Environmental Research (PEER) are more conservative, maintaining that at most “an additional 90 million m3 of wood could be harvested annually”.

Even allowing for a reduced increment, Dr van der Lugt says Europe “could build a half million houses from the 70million m3 increment that is not being harvested at the moment.”

Despite major challenges to Irish forestry in recent years, a wide range of stakeholders in the sector continue to promote forestry in all its aspects, especially in a range of projects, supported by the Department of Agriculture’s Open Call for Proposals for Forestry Promotion Projects last year. The following is a snapshot of some recent projects.

The North East Forestry Group

(NEFG), a forest owners’ network representing growers in counties Louth, Meath, Cavan and Monaghan are leaders in forest certification, promotion and education.

NEFG recently launched a new Classrooms into Woodlands for secondary students, which “connects students with real-life forest environments, offering practical lessons that directly support their classroom learning with bespoke tours,” said Derek McCabe, NEFG chair.

“This is a great initiative that will help to inspire the next generation and educate them on the role of trees and forests in the wider environment,” said Minister of State, Pippa Hackett, who launched the initiative.

John Sherlock, a long-time supporter of NEFG and past chair, encouraged secondary school teachers to book their classes for a local forest tour by logging on to northeastforestrygroup.ie.

Forestry and social media

The Society of Irish Foresters announced a series of updates and new ways to stay connected with forestry during the year.

“As part of our commitment to enhancing member engagement and creating a more dynamic online presence, we launched a newly redesigned website and we are stepping up our presence on social media through X and LinkedIn,” said Pat O’Sullivan, the society technical director.

“The updated website design (www.soif.ie) offers a modern, user-friendly experience with easier access to resources, new updates, and industry insights,” he said.

“To connect, share, and grow with our forestry community the society is now on X ( @Irish_Foresters) for policy and strategy updates, industry news, and conversations on forestry matters,” he added. For more information click here.

The society’s ‘Glimpses of Irish Forestry’ booklet is available free to schools and other stakeholders (contact info@soif.ie). And the society’s news and updates can be followed on LinkedIn

The Irish Timber Growers Association (ITGA) has a new YouTube channel, Let’s Talk Forestry, a Forest Owner’s Journey.

“It takes viewers through the life cycle of sustainably managed forests in Ireland, in terms of economic, environmental and social sustainability, as told by private woodland owners themselves,” said Donal Whelan, technical director ITGA.

“A different forest owner discusses forestry option and a wide range of forest management issues over 12 episodes.”

“Topics range from making the decision to plant and forest establishment through to felling and timber uses in the final episodes,” said Whelan.

“Topics include broadleaves and ACRES, agroforestry, continuous cover forestry, mixed high forest thinning and forest road construction,” he said. The channel was created by Linda Coghlan and Ryan Conway in collaboration with ITGA. For more information click here