Productive forestry deserves 'prominent role in climate policy' - new report

25 June 2021

A new academic report has concluded that productive forestry has a significant part to play in mitigating the impact of greenhouse gases - and deserves a “prominent role in climate policies”.’

Confor Chief Executive Stuart Goodall welcomed the report, Commercial afforestation can deliver effective climate change mitigation under multiple decarbonisation pathways, published in Nature magazine.

“We have said for a long time that productive forests that include a high proportion of conifers have a big part to play in our net zero journey and this shows that they need to be at the heart of the climate conversation,” Mr Goodall said.

The report was published this week, with two of the four researchers - Eilidh Forster and John Healey - from the School of Natural Sciences at Bangor University.

Speaking soon after the release of the report at the All Party Parliamentary Group on Forestry and Tree Planting, Eilidh Forster said: “Commercial forestry can deliver significantly more net carbon benefits than more natural broadleaf systems in the same time period, up to two and a half times more in some cases.”

The authors modelled 33 scenarios, looking at a range of different strategies - including ‘conservation forestry’ where trees aren’t harvested, and other strategies where harvested wood is prioritised for different uses.Its intention was to address “a gap in evidence determining the most effective type of temperate forestry for achieving Greenhouse Gas mitigation” – and it concluded that forest growth rate was “the most important determinant of cumulative mitigation by 2120”.

The report emphasises the efficacy of ‘commercial forestry’ for Greenhouse Gas (GHG) mitigation and concluded: “Commercial forestry therefore provides a robust strategy for GHG mitigation across a wide range of future contexts…and merits a prominent role in climate policies.”

It also says: “The study results highlight the effective and reliable contribution that commercial forestry could make towards the Paris Agreement even with projected decarbonisation of marginal materials and energy that are likely to be substituted by harvested wood products in the future. These results counter the conclusions of recent studies questioning the climate credentials of commercial forestry.”

The report also highlights the importance of starting to plant quickly – under the commercial forestry scenario, a forest planted today will achieve 20% more mitigation by 2050 than one planted in 5 years’ time and “only 15% of the 100-year mitigation will be achieved by 2050.”

Mr Goodall said: “This is a highly detailed report looking at a wide range of scenarios and it concludes what Confor - and the Climate Change Committee - have been saying for some time, that productive forestry is vital in the fight against climate change. It makes, as the report says, an ‘effective and reliable contribution’.

“At a time when productive forestry is facing criticism based on outdated assumptions, this is a report based on hard facts and thorough research.”

For the purposes of the report, ‘commercial forestry’ is defined as 100% Sitka spruce – an approach taken by the authors to allow a comparison with other species mix. Most modern productive forests include a maximum of around 50-60% spruce, under the UK Forestry Standard guidelines, alongside a mix of other conifer and broadleaved species.  

This means these forests won’t sequester quite as much carbon as the commercial forest scenario in the report. However, the data from the report confirms that the modern productive forests that are created in the UK today will deliver most for carbon sequestration.

The report notes that harvesting of “commercial forests” reduces long-term terrestrial carbon storage by 61%, but this is more than offset by carbon storage in harvested wood products, and concrete and energy substitution - even against the model used of near-total decarbonisation of the energy sector within the 100-year study horizon.

The report identifies that the substitution effect of harvested wood will reduce as other sectors become decarbonised, although it also makes the point that increased demand for wood for the ‘circular bio-economy’, including new products, could mitigate this reduction – consensus forecasts are that markets, and uses, for wood will increase significantly in the coming decades.

The report recognises that “fast-growing commercial forests managed for wood production have been unfavourably compared to restoration of natural forest” and then goes on to note: “There is some uncertainty about whether old forests may in fact continue to act as a significant carbon sink [when] unexpected losses from pests, pathogens, fires, windthrow and drought-caused mortality’ is considered – these risk factors are less likely in an actively managed forest with periodic harvesting.”  

Mr Goodall concluded: "Productive forests are designed to be managed."