Species-specific and ontogeny-related stem allometry of European forest trees: Evidence from extensive stem analyses

Constant allometric scaling as postulated by the metabolic scaling theory (MST) and the geometric scaling theory (GST) provides a promising synthesis for the functioning and structure of plants from organ to ecosystem level. Built on rather simple assumptions on individual structure and metabolism, both theories predict growth and morphology of trees albeit with different results. By analyzing tree stem allometry and comparing the results with general scaling rules our aim is to test and further develop allometric scaling theory. We base our analyses on 176 stem analyses each with up to 21 stem slices of dominant and codominant trees of Norway spruce (Picea abies [L.] Karst.), Scots pine (Pinus sylvestris L.), and European beech (Fagus sylvatica L.), aged 33-275 years. The sampled trees come from several locations across the Southern German federal state of Bavaria. Analysis of the scaling relationships between trunk diameter, tree height, and tree volume shows a considerable intraspecific variability, an interspecies difference in tree allometry and prevailing deviation from theoretical scaling rules, and a size- and time-related change of allometry. We discuss the results with respect to scaling theory and draw conclusions about the relevance of our findings for theory development and application in practice.