Coarse root architecture: Neighbourhood and abiotic environmental effects on five tropical tree species growing in mixtures and monocultures

Neighbourhood‐mediated shifts in tree biomass allocation drive overyielding in tropical species mixtures

“…fine roots; Brassard et al ., 2011; Germon et al ., 2018) and the spatial configuration of support organs (i.e. coarse roots; Madsen et al ., 2020) than on the fraction of biomass allocated belowground. We note, however, that our measurements of root biomass only included coarse roots, and thus did not account for changes in fine root biomass (≤ 2 mm in diameter).…”

“…The dry biomass of the root stump (belowground woody tissue within excavated 50‐cm radius circle centred on stem; n = 75) was regressed against tree basal area and subsequently used to estimate stump biomass for all target trees. For each target tree, the biomass of stump and coarse roots were summed to obtain an estimate of total tree root biomass (see details in Madsen et al ., 2020).…”

“…Spatial and temporal complementarity in species mixtures can mediate the availability of above‐ (light) and belowground (water, nutrient) resources for trees (Forrester & Bauhus, 2016), and may thus drive shifts in biomass allocation patterns. In turn, changes in within‐tree biomass allocation and branching patterns resulting from tree–tree interactions can affect crown and root architecture (Kunz et al ., 2019; Madsen et al ., 2020), and thus the amount of resources available for the trees.…”

Plasticity in branching and crown architecture helps explain how tree diversity increases tropical forest production

“…calculated the ratio of aboveground woody biomass to primary coarse root biomass (the ‘root‐to‐shoot ratio’) using the data published by Madsen et al . (2020), in which total tree root biomass was estimated by excavating the coarse roots around the tree stumps of a subsample (approximately half) of the trees that were harvested. Combining TLS and destructive harvest data, Guillemot et al .…”

“…Guillemot et al first measured these trees using terrestrial laser scanning (TLS) to precisely quantify wood volume and three-dimensional (3D) shape, and then destructively harvested and weighed trees to quantify total aboveground woody biomass. Guillemot et al calculated the ratio of aboveground woody biomass to primary coarse root biomass (the 'root-to-shoot ratio') using the data published by Madsen et al (2020), in which total tree root biomass was estimated by excavating the coarse roots around the tree stumps of a subsample (approximately half) of the trees that were harvested. Combining TLS and destructive harvest data, Guillemot et al quantified a suite of metrics describing tree woody biomass allocation (proportion of branch biomass allocated to primary, secondary, or tertiary branches) and crown architecture (total branch biomass, number, and specific length; crown metrics including volume, vertical irregularity, and projected area; tree slenderness).…”