Comparison of three temperate rainforest climate envelopes for Britain and Ireland: Where could our rainforest be?

<jats:title>Abstract</jats:title> <jats:p> <jats:list> <jats:list-item> <jats:p>Restoration of natural habitats is now recognised as a priority in both political and scientific circles. Temperate rainforests are internationally rare and endangered habitats, which are delineated from other woody biomes by high year‐round rainfall and moderate temperatures, and are restricted to mid‐latitude zones of the globe. With Britain and Ireland harbouring up to 40% of the potential range of European rainforest, this is a crucial region for their protection and restoration. Recent investment in tree planting and restoration initiatives in Ireland and Britain highlight the need for informed planning of native habitat and woodland creation to ensure long‐term stability under different climate change scenarios. While climate envelope modelling is widely used to map and delineate temperate rainforest zones, these models use a range of potential climatic thresholds, leading to uncertainty in defining the current temperate rainforest suitability zone.</jats:p> </jats:list-item> <jats:list-item> <jats:p>We compared three widely used climate envelopes for determining the temperate rainforest zones in Ireland and Britain: Amann's Index of Hygrothermy at over 100, Alaback's method and DellaSala's method.</jats:p> </jats:list-item> <jats:list-item> <jats:p>Significant differences were found between the models in the extent and distribution of the area climatically suitable for temperate rainforest, raising concern over the identification of the appropriate climate suitability envelope for targeting more localised restoration initiatives as well as indicating that speculation on past extent may be erroneous.</jats:p> </jats:list-item> <jats:list-item> <jats:p>The resulting areas of the potential temperate rainforest zone were often near the predicted limits of climatic suitability, creating a potential risk for long‐term suitability in a changing climate.</jats:p> </jats:list-item> <jats:list-item> <jats:p> <jats:italic>Practical implication</jats:italic> : Guidance on what constitutes necessary climatic conditions for temperate rainforest persistence is required for appropriate conservation, restoration and expansion of this habitat type in Ireland and Britain. A lack of agreement between approaches impedes confidence in modelling where suitable conditions for rainforest currently exist and how climate change might alter this distribution in the future. Going forward, improved collaboration between scientists and modellers with restoration practitioners and policymakers could help facilitate more regionally appropriate definitions, models and mapping tools for restoration and expansion of temperate rainforest. </jats:p> </jats:list-item> </jats:list> </jats:p>