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1/Tree planting forms a prominent part of climate change mitigation strategies often including area-based targets. Recent @SGRESAS funded research shows that the amount of trees you plant doesn’t necessarily result in net carbon gains https://bit.ly/3iqPi1W THREAD
2/ First, congratulations to the project team who are made up of colleagues from @JamesHuttonInst @aberdeenuni and @Forest_Research. This is the result of sustained funding and collaboration over many years.
3/ The team produced a new way to quantify the potential carbon storage of 11 different forest management alternatives in Scottish locations. This forms the basis for a new a mapping tool https://woodlandexpansion.hutton.ac.uk/
4/ The maps show the
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ground C & where net C surpluses and deficits are likely to occur, how long they persist after afforestation and how they vary with pre-existing land use, soils, weather conditions and afforestation management strategies
& ground C & where net C surpluses and deficits are likely to occur, how long they persist after afforestation and how they vary with pre-existing land use, soils, weather conditions and afforestation management strategies
5/11 management regimes were used to assess the differences in carbon stored in trees. These characterise the broad range of afforestation types likely to occur in Scotland & defines combinations of tree species, anticipated yields and management (rotation periods & thinning)
6/ The range of possible outcomes are substantial but a key thing to note is that conversion from semi-natural land use across all the management regimes sees net losses for the first 20 yrs & even by 80 yrs, some are still on average net emitters or are only just breaking even
7/ In early years, even for some production-oriented woodlands, net losses occur especially on organo-mineral soils & this would mean that new plantings would not positively contribute to mitigation within the time frames of the commitments in the Climate Change (Scotland) Act.
8/Take away messages: The paper supports the statutory presumption against planting trees on deep peat areas (>50 cm of peat in top 100 cm of soil). Planting more trees on more productive classes of land will sequester more carbon sooner & help us meet our emissions targets
9/This doesn’t necessarily require afforesting on land already being used e.g. food production but farmers/landowners will need additional support to enable this integration & realise the multiple from their land. END
