Competitive drivers of interspecific deviations of crown morphology from theoretical predictions measured with Terrestrial Laser Scanning

Tree crown morphology is a key driver of forest dynamics, determining not only the competitiveness an individual but also competitive effect exerted on neighbouring trees. Multiple ecological theories, including metabolic scaling theory (MST), predict from first principles, typically lack consideration competition. The accurate quantification to test theoretical predictions, and canopy interactions that could alter them, has historically been limited by simplicity associated error traditional measurements. In this study, we calculate high-resolution two- three-dimensional metrics Terrestrial Laser Scanning data for 1,441 Pinus sylvestris, P. nigra, Quercus faginea Q. ilex trees water-limited community in central Spain height-crown metric relationships. We demonstrate new TLS methods define symmetric asymmetric neighbourhood based tree height, size neighbour projected area, importance genus diversity separating competition congeneric heterogeneric neighbours. Competition negatively impacted all except depth where nigra showed sensitivity. Asymmetric was strongest pine morphology, oaks were more sensitive competition, line with shade tolerance expectations. Congeneric reduced changed its shape, found no significant effects Most species dimensions had exponents below those predicted MST, which may be due water limitation effects. Pines large differences height scaling, former shallower latter deeper, contrast predictions. Synthesis. Our study ability characterise leaf-wood separated clouds community, use theory. scaled larger neighbours crowding neighbours, same having consistent negative effect.