Revisiting the relative growth rate hypothesis for gymnosperm and angiosperm species co‐occurrence

Premise of the Study It is unclear to what extent the co‐occurrence of angiosperm and gymnosperm species in some marginal ecosystems is explained by reduced growth in angiosperms due to carbon (C) limitation and by high stress tolerance in gymnosperms associated with lack of vessels and resource conservation. Methods We examined growth patterns and traits associated with C balance in four evergreen angiosperm species (including one vesselless species, Drimys winteri ) and three gymnosperm tree species of a cold‐temperate rainforest in southern Chile. We measured the mean basal area increment for the first 50 ( BAI 50 ) and the last 10 years ( BAI 10 ), wood density, leaf lifespan, and nonstructural carbohydrate ( NSC ) concentrations in different organs. Key Results BAI 50 was 6‐fold higher in angiosperms than in gymnosperms and ca. 4‐fold higher in Drimys than in the fastest‐growing gymnosperm. BAI 10 and aboveground NSC concentrations were significantly higher and leaf lifespan lower in angiosperms than in gymnosperms; these differences, however, were largely driven by the slow growth and low NSC concentrations of the Cupressaceae species ( Pilgerodendron uviferum ), while the two Podocarpaceae had BAI 10 and NSC concentrations similar to angiosperms. In angiosperms, NSC and starch concentrations were generally higher in species with lower BAI 10 , indicating no severe C limitation. Conclusions The co‐occurrence of angiosperms and gymnosperms in cold‐temperate rainforests of southern Chile is not explained by growth disadvantages and C limitation in angiosperms. Long leaf longevity, but not lack of vessels, appeared to favor resource conservation and C balance in some gymnosperms (Podocarpaceae).