Allometric models based on limited sub-samples are widely used for predicting forest-scale information. Here, we develop allometric models for the branch surface area of the widespread conifer species Picea abies [L.] Karst. Branch surface area is a proxy for the capacity of tree branches to intercept and store water and air pollutants. Based on “probability proportional to size” sampling, we measured the surface area for 285 branches and then calculated the branch surface area of 30 trees (and their 3298 branches). We developed allometric models to estimate the total surface area of branches, as well as their number and diameters, for trees across a range of diameters (DBH), heights, and crown ratios (CR). We show that DBH and CR play significant roles in branch characteristics. The branch surface area was linearly related to the stand basal area. Reducing stand density will proportionally reduce interception capacity. The approach outlined here may help stimulate further studies (more species, regions, and management practices) required to optimize stand density for ecosystem services related to crown characteristics, such as hydrology, forage quality, and quantity or capacity for air pollutants.
