Differences in fine root productivity between mixed‐ and single‐species stands

Abstract

Summary1. The diversity-productivity debate has so far been focused above-ground, despite that belowground production can account for approximately half of total annual net primary production, mostly from fine roots. 2. Here, we investigate the fine root productivity of mature, fire-origin stands of Populus tremuloides -Picea spp. -Abies balsamea (mixed-species stands) and relatively pure P. tremuloides (single-species stands) in two regions of North American boreal forest to better understand the link between plant diversity and below-ground productivity in forest ecosystems. We hypothesized that: (i) mixed-species stands have higher fine root productivity compared with single-species stands and (ii) this difference may be the result of greater soil space filling by the fine roots due to the contrasting rooting traits of the component species in the mixed-species stands. 3. We found that fine root productivity, measured by annual production and total biomass, was higher in mixed-than single-species stands. We also found that mixed-species stands had lower and higher horizontal and vertical fine root biomass heterogeneity, respectively, indicating that soil space is more fully occupied by fine roots in the mixed-than single-species stands. 4. In all, our study supports that below-ground niche differentiation may be a key driver of higher fine root productivity in mixed stands of species with contrasting rooting traits than single-species stands by facilitating greater soil space filling of fine roots and soil resource exploitation.

European Mixed Forests: definition and research perspectives

“…However, few studies have examined belowground productivity in mixtures and even fewer have compared above-and belowground productivity (Forrester et al, 2006;Epron et al, 2013). Belowground overyielding has not been demonstrated to occur in mature temperate forests (Meinen et al, 2009a(Meinen et al, , 2009bJacob et al, 2013) although root differentiation led to higher fine root productivity in young stands (Lei et al 2012) whereas in boreal forests fine root overyielding was observed in mature stands originated after fire (Brassard et al, 2011). Interspecific competition can also have a strong impact on crown structure (Bayer et al, 2013) and crown allometry .…”

Estimating fine-root production by tree species and understorey functional groups in two contrasting peatland forests

“…Conventionally, when ingrowth cores with short incubation times (1 or < 2 yr. ) are used, FRP is estimated as the mass of the fine roots extracted from the ingrowth core (Idol et al 2000;Valverde-Barrantes et al 2007;Aragão et al 2009;Brassard et al 2011;Laiho et al 2014). But using such short incubation times (< 2 yr) may result in underestimation (Steele et al 1997;Vogt et al 1998;Finér and Laine 2000).…”

A Review of Processes Behind Diversity—Productivity Relationships in Forests

“…[ 16,[80][81][82][83][84][85] Nutrient mineralization P F Changes in nitrogen mineralization and nitrification rates can influence nitrogen availability. Lack of mycorrhizal colonization of tree roots in non-native species may be overcome through admixture of native species and increase uptake.…”