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Harvard Forest Symposium Abstract 2018

• Title: Ecological Investigations of Forest History in the Old-growth Forest above Gill Brook in the Ausable Club’s Adirondack Mountain Reserve
• Primary Author: Neil Pederson (Harvard Forest)
• Additional Authors: David Orwig (Harvard Forest)
• Abstract:

  As part of a larger effort to build a database of forest disturbance from a network of old-growth forests across the Northeastern U.S., we sampled trees in the Adirondack Mountain Reserve on Ausable Club land in 2015 and 2016. We established 3 plots and cored over 250 trees to examine composition, structure, tree age, and recruitment dynamics. The forests were a mix of hardwood and softwood species including sugar maple, American beech, red spruce, eastern hemlock, yellow birch, and striped maple. Age structure analysis across all three plots suggest eastern hemlock and yellow birch were consistently the oldest trees we sampled (Fig. 1). The oldest trees we cored in our three plots were eastern hemlock that dated back to 1575, or 442 years old. This makes them the oldest known hemlock in the Adirondacks to date. In addition 2 white ash trees were 291 and 304 years old, respectively, making them the oldest known white ash anywhere in the US. Sugar maple became more important during the 1800s, and beech in the 1900s. Recruitment peaked between the 1900 and 1925. Smaller peaks appear in the late 1700s and 1950s. Upon examination of individual tree growth patterns (Fig. 2), we found evidence for both asynchronous events that indicate small, low-intensity disturbances that cause small canopy gaps randomly in space and time (the increase in radial growth seen only in ash during the 1840s) and synchronous events that influenced several species (the significant increase in radial growth of sugar maple, beech and hemlock in the 1970s. Additional work will synthesize these results across plots and add them to the growing tree-ring network being developed to more fully describe the past disturbance dynamics at large spatial and temporal scales in the eastern U.S.

• Research Category: Historical and Retrospective Studies
  Regional Studies


• Figures:
Fig 1 gill brook ages.docx
Fig 2 disturbance history.docx