Document Type

Review

Robert Seymour

Publication Title

Maine Woodlands

Publisher

Maine Woodland Owners

Publication Date

Winter 2-2026

Publisher location

Augusta, Maine

Issue Number

1, 2

Volume Number

51

Abstract/ Summary

Forest stand dynamics is the study of changes in stand structure over time and the behavioral responses of forests to disturbances. These natural trajectories are shaped by disturbance regimes, defined by parameters like frequency and return intervals, which range from infrequent stand-replacing events to frequent small-scale gaps. Following a major disturbance, stands typically progress through four developmental stages: initiation, where new recruitment occurs; stem exclusion, where the overstory prevents new growth; understory reinitiation, where crown abrasion creates space for shade-tolerant species; and old growth, where recruitment is continuous in canopy gaps. Throughout these stages, competitive interactions lead to differentiation in monocultures, forming distinct crown classes—dominant, codominant, intermediate, and overtopped—based on light access. In mixed-species stands, this process is known as stratification, resulting in vertical strata (A, B, and C) that reflect varying shade tolerances and growth potentials.

These structural changes are regulated by biological principles such as self-thinning, which follows a predictable -3/2 power law relating tree size to density, and light extinction, which triggers crown recession as lower branches die from shading. Mastery of these dynamics allows practitioners to apply targeted interventions, such as crown thinnings to enhance vigor or shelterwood sequences for regeneration, ensuring management aligns with ecological constraints and long-term goals.

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