Document Type

Article

Publication Title

Maine Woodlands

Publisher

Maine Woodland Owners

Publication Date

Winter 2-2020

Publisher location

Augusta, Maine

Issue Number

2

Volume Number

45

Abstract/ Summary

Forest productivity in Maine is inextricably linked to post-glacial soil development and topographic positioning. Approximately 12,000 years ago, retreating glaciers deposited an unsorted mixture of minerals known as glacial till, which serves as the primary parent material for contemporary forest soils. The depth of the B horizon largely determines the functional quality of a site, the primary zone for root development; deep, well-drained soils support good tree growth compared to shallow or saturated ones.

Soil fertility is further influenced by texture and decomposition rates. While a thick organic (O) horizon might suggest high fertility, rapid decomposition in thinner layers more effectively releases nutrients, such as nitrogen, for tree uptake. Texture varies from fine lacustrine clays to coarse granite-based sands. Excessively drained outwash soils favor species with low nutrient requirements, such as pines, while fine-grained marine sediments are inherently fertile but often suffer from poor drainage.

Topographic position along a catena—a group of soils with shared parent material but different drainage classes—critically dictates species distribution. The most productive sites are typically found on lower slopes and enriched tills, where subsurface seepage enhances moisture and nutrients. On these high-quality sites, hardwoods such as sugar maple and ash maintain a competitive advantage. Effective silviculture requires aligning management goals with these natural site conditions, as attempting to shift a stand away from its ecologically adapted species necessitates intensive intervention to combat natural succession.

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