Needle-retention and density patterns in <i>Pinus sylvestris</i> in the Rhone Valley of Switzerland: comparing results of the needle-trace method with visual defoliation assessments

Abstract

We used the needle-trace method (NTM) to reveal the needle-retention patterns of Scots pine (Pinus sylvestris L.) over the past 100 years. The average annual needle retention (ANR) on main stems ha...