Changes in composition, structure and aboveground biomass over seventy-six years (1930–2006) in the Black Rock Forest, Hudson
Highlands, southeastern New York State
W. S. F. Schuster (1, 2), K. L. Griffin (3), H. Roth (4), M. H. Turnbull (5), D. Whitehead (6) and D. T. Tissue (7)
1. Black Rock Forest Consortium, 129 Continental Road, Cornwall, NY 12518, USA / 2. Corresponding author () / 3. Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, 6 Biology, Palisades, NY 10964, USA / 4. Department of Environmental Science, Barnard College, 3009 Broadway, 404 Altschul Hall, New York, NY 10027, USA / 5. School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand / 6. Landcare Research, P.O. Box 40, Lincoln 7640, New Zealand / 7. Department of Biology, Texas Tech University, Lubbock, TX 79409-3131, USA / Received March 1, 2007; accepted June 9, 2007; published online February 1, 2008
Summary
We sought to quantify changes in tree species composition, forest structure and aboveground forest biomass (AGB) over 76 years
(1930–2006) in the deciduous Black Rock Forest in southeastern New York, USA. We used data from periodic forest inventories,
published floras and a set of eight long-term plots, along with species-specific allometric equations to estimate AGB and
carbon content. Between the early 1930s and 2000, three species were extirpated from the forest (American elm (Ulmus americana L.), paper birch (Betula papyrifera Marsh.) and black spruce (Picea mariana (nigra) (Mill.) BSP)) and seven species invaded the forest (non-natives tree-of-heaven (Ailanthus altissima (Mill.) Swingle) and white poplar (Populus alba L.) and native, generally southerly distributed, southern catalpa (Catalpa bignonioides Walt.), cockspur hawthorn (Crataegus crus-galli L.), red mulberry (Morus rubra L.), eastern cottonwood (Populus deltoides Bartr.) and slippery elm (Ulmus rubra Muhl.)). Forest canopy was dominated by red oak and chestnut oak, but the understory tree community changed substantially
from mixed oak–maple to red maple–black birch. Density decreased from an average of 1500 to 735 trees ha–1, whereas basal area doubled from less than 15 m2 ha–1 to almost 30 m2 ha–1 by 2000. Forest-wide mean AGB from inventory data increased from about 71 Mg ha–1 in 1930 to about 145 Mg ha–1 in 1985, and mean AGB on the long-term plots increased from 75 Mg ha–1 in 1936 to 218 Mg ha–1 in 1998. Over 76 years, red oak (Quercus rubra L.) canopy trees stored carbon at about twice the rate of similar-sized canopy trees of other species. However, there has
been a significant loss of live tree biomass as a result of canopy tree mortality since 1999. Important constraints on long-term
biomass increment have included insect outbreaks and droughts.
