Root System Differences Among Species: Implications for Early Successional Changes in Forest of Western Oregon

Abstract

-Differences in root systems among species may contribute to compositional changes during succession. We excavated all belowground parts of species in an early successional community 2-3 yr after logging and burning of an old Pseudotsuga menziesii forest. Annual species had a similar overall root system morphology, but varied in characteristics such as rooting depth and root/shoot ratio. Seedlings of perennial species generally had higher root/shoot ratios than did annuals. Mature perennials had extensive root systems with high root/shoot ratios and most species were clonal. Species typical of later successional stages had more extensive and deeper root systems than did species of earlier stages, a factor that may influence compositional change. Some species that persist throughout succession may do so because their root systems are flexible, changing in origin and distribution. Differences in root systems among species are consistent with their successional roles and habitat affinities, and thus, are important in understanding species replacement during secondary