Windthrow and salvage logging in an old-growth hemlock-northern hardwoods forest

Abstract

Although the initial response to salvage (also known as, post-disturbance or sanitary) logging is known to vary among system components, little is known about longer term forest recovery. We examine forest overstory, understory, soil, and microtopographic response 25 years after a 1977 severe wind disturbance on the Flambeau River State Forest in Wisconsin, USA, a portion of which was salvage logged. Within this former old-growth hemlock-northern hardwoods forest, tree dominance has shifted from Eastern hemlock (Tsuga canadensis) to broad-leaf deciduous species (Ulmus americana, Acer saccharum, Tilia americana,Populus tremuloides, and Betula alleghaniensis) in both the salvaged and unsalvaged areas. While the biological legacies of pre-disturbance seedlings, saplings, and mature trees were initially more abundant in the unsalvaged area, regeneration through root suckers and stump sprouts was common in both areas. After 25 years, tree basal area, sapling density, shrub layer density, and seedling cover had converged between unsalvaged and salvaged areas. In contrast, understory herb communities differed between salvaged and unsalvaged forest, with salvaged forest containing significantly higher understory herb richness and cover, and greater dominance of species benefiting from disturbance, especially Solidago species. Soil bulk density, pH, organic carbon content, and organic nitrogen content were also significantly higher in the salvaged area. The structural legacy of tip-up microtopography remains more pronounced in the unsalvaged area, with significantly taller tip-up mounds and deeper pits. Mosses and some forest herbs, includingAthyrium filix-femina and Hydrophyllum virginianum, showed strong positive responses to this tip-up microrelief, highlighting the importance of these structural legacies for understory biodiversity. In sum, although the pathways of recovery differed, this forest appeared to be as resilient to the compound disturbances of windthrow plus salvage logging as to wind disturbance alone, by most vegetative measures.

Soil microbial characteristics at the monitoring plots on windthrow areas of the Tatra National Park (Slovakia): their assessment as environmental indicators

“…Windthrow areas are usually cleared; harvesting of disturbed stands is practiced for the economic (recouping of the financial losses before wood-quality deterioration) and sanitary reasons (damaged trees can attract insects and consequently insects can attack undisturbed trees in their neighbourhood). Recently, there appeared studies discussing the impact of the post-disturbance logging as a combination of natural disturbance and subsequent harvesting on one side, and the impact of natural disturbance or clear-cutting alone on the other side (Lindenmeyer and Noss 2006;Lang et al 2009). As the authors emphasised, the main question is whether different management alters forest recovery, biodiversity, etc.…”

Influence of salvage logging on forest recovery following intermediate severity canopy disturbances in mixed beech dominated forests of Slovenia

“…While there is clear evidence of the negative effects of salvaging on regeneration in some circumstances (e.g., large-scale high severity disturbance and salvaging - Donato et al 2006, Jonasova et al 2010), the evidence is less clear following a combination of intermediate severity disturbance and salvage logging (Peterson & Leach 2008a, Lang et al 2009, D'Amato et al 2011, Kramer et al 2014. It is important to note that we focused on the influence of salvage logging on vegetation in this study.…”

“…Peterson & Leach (2008a, 2008b they found clear differences in microsite diversity and abundance between the two treatments, the density and diversity of herbs and tree seedlings did not show a detrimental response to salvaging. Lang et al (2009) followed the long-term vegetation response to non-salvage and salvage treatments in a mixed forest damaged by severe wind in Wisconsin, USA. They found that the structure and composition of tree species on both treatments largely converged after 25 years, despite substantial damage to advance regeneration during salvage operations.…”

A Demographic Approach to Evaluating Tree Population Sustainability

“…Wind disturbance usually does not facilitate the establishment of pioneer species, and late-successional species largely remain dominant [30][31][32]. Long-distance colonization by species of relatively low shade tolerance (e.g., Betula papyrifera Marsh., Populus tremuloides Michx., Pinus strobus L.) occurs primarily after fire.…”