Adventitious root production and plastic resource allocation to biomass are adaptive traits of coastal dune woody plants in central Canada, and provide a basis for assessing burial tolerance in woody plants on coastal dunes throughout the world.

The zonation of coastal dune plant communities from the beach to their inland margin is recognized worldwide; however, the cause of this pattern remains controversial because of the covariance of several environmental factors, such as sand burial, salt spray, and microclimate, along a gradient perpendicular to the shoreline. To minimize the confounding influence of this complex shore–inland gradient and determine the direct effects of burial on plant community composition, we examined stands along a burial gradient that extended parallel to the Lake Huron coastline, produced by variable blowout activity amongst a series of parabolic dunes comprising the second ridge inland from the coast. We used the point-quarter method and 1 m × 1 m plots to quantify overstorey and understorey plant communities in each parabolic dune stand and determined species importance, here defined as the sum of density, frequency, and dominance for the overstorey and the sum of frequency and dominance only for the understorey. Correspondence analyses of the species importance – dune stand matrices elucidated a pattern of plant community composition on the primary ordination axis that was strongly related to an index of burial activity (r2 = 0.40 and 0.87 for the overstorey and understorey, respectively). Burial was associated with changes in species richness and diversity, shifts in dominant species, and species replacement based on burial tolerance across the gradient. These data support the hypothesis that burial in sand dunes is a major causative factor of zonation, which can extend beyond the foredunes and include communities of woody species.Key words: coastal dunes, vegetation, zonation, woody plants, burial.

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Enhanced forest resources inventory systems delineate and define polygons based on fundamental ecological units such as ecosites, which are standard combinations of vegetation and substrate types. Our study objective was to model wood quality characteristics of individual black spruce (Picea mariana (Mill.) B.S.P.) trees across a representative boreal forest landscape in northeastern Ontario, Canada, based on relationships to ecosite and other stand-level variables. A total of 127 large (12 mm) increment core samples were extracted at breast height from dominant or co-dominant black spruce trees in forest stands representing a gradient from dry sandy to wet mineral and organic ecosites. Sample cores were prepared, processed, and analyzed using standard SilviScan protocols. Hierarchical classification models were then fitted using Random Forests to predict density and latewood percentage for black spruce stems at a reference age of 50 years. These models each explained over 32% of variance, with estimated root mean squared errors of 40.4 kg·m−3 and 5.6% for density and latewood percentage, respectively. Among tree-, site-, and stand-level covariates, ecosite group was the most important predictive variable. Knowledge of ecosite – wood quality relationships could support efficient planning for black spruce management by including an indication of potential use as a modeled variable in a forest inventory system.