Roles of wood anatomical traits in the coexistence of Mexican oak species

Oaks (Quercus spp.) are a dominant tree genus of the northern hemisphere, occurring natively in North America, Europe, Asia, and northern Africa. Oak trees occupy a wide range of habitats, from Mediterranean semi-desert ecosystems to subtropical rainforests, and are highly ecologically diverse. In Mexico, oaks have undergone extraordinary diversification along the different mountain chains, resulting in the presence of several endemic species.

In their new Editor’s Choice study published in AoBP, Arenas-Navarro et al. analysed wood anatomical traits and the relative hydraulic conductivity of 21 oak species of the ‘El Tuito-El Cuale-Talpa de Allende’ Sierras mountains in west Mexico. The main vegetation types of this region are tropical deciduous forests at low elevations, oak, pine-oak and fir forests at high elevations and montane cloud forests in glens. In their study, Arenas-Navarro et al. aimed to identify how variation in wood anatomical traits was driven according to abiotic factors, leaf phenological patterns and phylogenetic restrictions by analysing interspecific variation along an environmental gradient.

The authors found that high temperatures combined with periodic water deficits lead to narrower vessels and high-density wood occupied by smaller fibres. On the contrary, at more humid sites, tall oaks invest in the widest vessels to conduct water with greater efficiency. The oak species in the study site showed an adaptive response of wood traits to climate, but there was also evidence of a low phylogenetic signal. Arenas-Navarro et al. conclude that the co-occurrence of oak species with different leaf habits and phylogenetic trajectories may promote complementary resource acquisition.

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Maribel Arenas-Navarro, Ken Oyama, Felipe García-Oliva, Andrés Torres-Miranda, Enrique G de la Riva, Teresa Terrazas, The role of wood anatomical traits in the coexistence of oak species along an environmental gradient, AoB PLANTS, Volume 13, Issue 6, December 2021, plab066, https://doi.org/10.1093/aobpla/plab066