Publication Details

The formation of dense understory layers in forests worldwide: consequences and implications for forest dynamics, biodiversity, and succession

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Royo, Alejandro A.; Carson, Walter P.

Year Published

2010

Publication

In: Pye, John M.; Rauscher, H. Michael; Sands, Yasmeen; Lee, Danny C.; Beatty, Jerome S., tech. eds. Advances in threat assessment and their application to forest and rangeland management. Gen. Tech. Rep. PNW-GTR-802. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 469-496.

Abstract

Alterations to natural herbivore and disturbance regimes often allow a select suite of forest understory plant species to dramatically spread and form persistent, mono-dominant thickets. Following their expansion, this newly established understory canopy can alter tree seedling recruitment rates and exert considerable control over the rate and direction of secondary forest succession. No matter where these native plant invasions occur, they are characterized by one or more of the following: (1) the understory layer typically has greater vegetation cover and lower diversity than was common in forest understories in the past; (2) this layer can delay stand renewal and alter species composition by inhibiting tree regeneration; and (3) once this layer is formed, it can resist displacement by other species and remain intact for decades. In this paper, we evaluate the processes that trigger the expansion of several plant species native to forests and review their ecological characteristics to provide general guidelines in assessing native invasion risk in forest stands.

Citation

Royo, Alejandro A.; Carson, Walter P. 2010. The formation of dense understory layers in forests worldwide: consequences and implications for forest dynamics, biodiversity, and succession. In: Pye, John M.; Rauscher, H. Michael; Sands, Yasmeen; Lee, Danny C.; Beatty, Jerome S., tech. eds. Advances in threat assessment and their application to forest and rangeland management. Gen. Tech. Rep. PNW-GTR-802. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 469-496.

Last updated on: November 23, 2010