Tree-ring analysis of red spruce timbers from the Moosilauke Ravine Lodge, White Mountains, New Hampshire

Abstract

Historic harvesting and mortality from air pollution drastically reduced the abundance of red spruce (Picea rubens), a late-successional dominant of cool-temperate forests of the northeastern U.S. and southeastern Canada, leaving few opportunities to understand the natural growth and disturbance responses of this species. Timbers salvaged from the Moosilauke Ravine Lodge, a structure built from trees harvested in the late 1930s, provided an opportunity to reconstruct radial growth patterns and dynamics of a former old-growth red spruce stand located in Jobildunc Ravine on Mount Moosilauke in the White Mountains of New Hampshire. Ravine Lodge tree-ring series were compared with data from a 255-year-old red spruce found living in Jobildunc Ravine, from the Nancy Brook site in the White Mountains, and from other dendroecological studies across the region. Ring counts provide minimum tree ages of 187–286 years for timbers from Jobildunc Ravine, suggesting they established between the mid-Seventeenth and mid-Eighteenth Centuries. Dendroecological analyses identified early decades of suppression in the understory followed by 2–5 growth releases and 2–4 growth declines for each sample, indicating occasional, small-scale disturbances of the canopy before the 1930s. A growth decline in 1834–1835 coincides with an outbreak of spruce budworm (Choristoneura fumiferana) in eastern Canada, perhaps reflecting a regional defoliation event that occurred as far south as Mount Moosilauke. This study illustrates the insights that can be gained from wood from historic structures on the dynamics of now-scarce old-growth red spruce forests.