Thinning strategies and their impact on growth dynamics, allocation patterns and water use efficiency in Scots pine stands

Sammanfattning

Scots pine (Pinus sylvestris L.) is one of the most important tree species in Europe. The first thinning fills the purpose of shaping the stand for future growth through the selection of which trees to retain. This thesis aimed to explore the mechanistic basis of thinning responses in the short-term, through the establishment of thinning experiments in central Sweden, which included biomass harvests and continuous monitoring of sap flow and stem radial change. Long-term thinning strategies were evaluated using a series of thinning experiments across Sweden. The results show that Scots pine trees were able to swiftly adjust biomass allocation strategies. Although thinning, by design, reduces leaf area index (LAI) and standing biomass, an increased growth for individual trees, on average, and for dominant trees, was immediate. After thinning, the stands presented higher water use efficiency. Indirect measurements were not able to detect substantial changes in LAI and root distribution between years. In the long-term evaluations of selective and schematic thinnings, it was observed that the amount of retained basal area is more important for tree growth and stand development than the spatial distribution of trees. With imminent changes in the climate and the possibility of increased frequency and intensity of droughts and other extreme events, it becomes important to adapt management alternatives to mitigate the negative effects of such changes. This thesis demonstrates that thinning has the potential to contribute to greater resilience of Scots pine forests in the boreal zone.

Nyckelord

forest management; ecophysiology; scots pine; growth; transpiration; water use efficiency; biomass quantification; skogsskötsel; ekofysiologi; tall; tillväxt; transpiration; vattenanvändningseffektivitet; biomassa

Publicerad i

Acta Universitatis Agriculturae Sueciae
2025, nummer: 2025:34
Utgivare: Swedish University of Agricultural Sciences

SLU författare

• de Castro Segtowich, Amanda

  • Institutionen för sydsvensk skogsvetenskap, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Skogsvetenskap

Publikationens identifierare

• DOI: https://doi.org/10.54612/a.4c0s1fpl24
• ISBN: 978-91-8046-469-7
• eISBN: 978-91-8046-519-9

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/132974