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Abstract
Unlike trees, shrubs (i.e., multiple-stemmed woody plants) do not need evenly spaced large diameter structural roots and therefore should be more responsive to heterogeneous distributions of soil resources and spread further per unit belowground biomass. We therefore hypothesized that compared to trees, shrubs respond more to asymmetric distributions of nutrients, reach nutrient-rich patches of soil faster, and do so with less below-ground biomass. To test these three hypotheses, we planted individual seedlings of shrubs (Cornus racemosa, Rhus glabra, and Viburnum dentatum) and trees (Acer rubrum, Betula populifolia, and Fraxinus americana) in the centers of sand-filled rectangular boxes. In one direction we created a stepwise gradient of increasing nutrients with slow-release fertilizer in the other direction, no fertilizer was added. Seedlings were harvested when their first root reached the plexiglass-covered fertilized end of their box time taken, above-ground biomass, and below-ground biomass per nutrient segment were determined. Shrubs and trees did not consistently differ in precision of root foraging (i.e., the ratio of biomass in the fertilized and unfertilized soil) or in rates (g/day) and efficiencies (cm/day) of lateral root growth. Interspecific variation appeared more related to species’ habitats than to growth form. The fastest and most efficient roots were produced by the shrub (R. glabra) and the tree (B. populifolia), both characteristic of poor and heterogeneous soils. Root foraging by R. glabra was also facilitated by rapid rhizomatous expansion.
Department
Earth Systems Research Center
Publication Date
4-3-2024
Journal Title
Plant Ecology
Publisher
Springer Science and Business Media LLC
Digital Object Identifier (DOI)
Document Type
Article
Recommended Citation
Putz, F.E., Canham, C.D. & Ollinger, S.V. Belowground exploration by trees and shrubs. Plant Ecol 225, 605–610 (2024). https://doi.org/10.1007/s11258-024-01416-7
Comments
This is an open access article published by Springer Science and Business Media LLC in Plant Ecology in 2024, available online: https://dx.doi.org/10.1007/s11258-024-01416-7