Leif Kullman 2021. Recently Enhanced Pine (Pinus sylvestris L.) Regeneration and Extensive Penetration towards the Head of the Handölan Valley: Reversal of a Long-Term Retrogressional Trend – Contrasting Responses to Climate Change of Tree- and Forest Line. Challenging Issues on Environment and Earth Science Vol. 3. (Apr. 2021), 44–58. DOI:https://doi.org/10.9734/bpi/ciees/v3/8096D.