Exploring the geographic variation in needle shoot architecture with 3D photogrammetry

Abstract

The study examined Norway spruce (Picea abies (L.) H.Karst.) shoot architecture from three northern European sites using high-precision blue light 3D photogrammetry. The main parameters analysed were the silhouette to total shoot area ratio (STARshoot), Silhouette to total needle area ratio (STARneedle), and silhouette contour length. The objectives were: creating accurate 3D models, calculating and comparing these parameters across a latitudinal gradient, and assessing the impact of different STAR definitions. The analysis revealed an average 11.8% difference between STARshoot and STARneedle, indicating the need for consistent definitions. No statistically significant geographic variation in shoot structure was found, suggesting potential architectural consistency across the study sites.