Effects of planting density on the performance of reforestation and afforestation plantings in temperate and boreal forests: a systematic review

Sammanfattning

IntroductionRising demand for forest products, climate mitigation, and ecosystem restoration has driven international pledges to expand forests, mostly on abandoned agricultural lands and areas of low conservation value. According to a recent survey among restoration practitioners across Europe, optimal planting designs and densities are key questions for reforestation efforts.ObjectivesWe aimed to determine how planting density affects the performance of reforestation/afforestation plantings, how these effects vary by climate, species types, and stand age, and whether there are planting density thresholds triggering significant performance shifts.MethodsUsing both descriptive statistics and meta-analyses, we systematically reviewed 120 studies from temperate and boreal forests to analyze planting density effects on the performance of tree plantings.ResultsHigher planting densities increase overall yield but also mortality. Negative effects on individual stem growth occur mainly at early ages, while negative impacts on individual stem growth and survival intensify over time. Benefits on stand yield are observed at both young and old ages, and there are no clear differences in the density response of shade-tolerant and shade-intolerant species. On average, an increase in planting density of 71 and 118% is needed to cause significant impacts on performance at stand-level and individual-tree level, respectively, though effects vary across studies and variables.ConclusionsObserved patterns aligned with expectations, as higher planting densities increased mortality and lowered individual growth while promoting overall yields. However, the timing and thresholds of positive and negative effects vary, presenting opportunities to optimize management through variable densities over time.

Nyckelord

planting design; restoration practices; silviculture; stand dynamics; tree growth; tree regeneration

Publicerad i

Restoration Ecology
2025
Utgivare: WILEY

SLU författare

• Jonsson, Bengt-Gunnar

  • Institutionen för vilt, fisk och miljö, Sveriges lantbruksuniversitet
    
  • Mittuniversitetet

UKÄ forskningsämne

Skogsvetenskap

Publikationens identifierare

• DOI: https://doi.org/10.1111/rec.70103

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/142719