Hurricane Recovery Plots

• Investigators: David Foster, David Hibbs, Toby Korsgren, Cathy Mabry, Steven Spurr
• Contact: David Foster
• Start date: 1937-01-01
• End date: ongoing
• Location: Harvard Forest
• Latitude: +42.45 to +42.55
• Longitude: -72.23 to -72.16
• Elevation: 205 to 420 meters
• Taxa:
• Keywords: forest dynamics, hurricane, regeneration
• Release date: 2000
• EML version: knb-lter-hfr.40.2
• Revisions:
• Abstract:

  The New England hurricane of 1938, by destroying many acres of mature and semi-mature forests, initiated new forest associations over a large area. Permanent plots were established across the Harvard Forest in severely damaged stands (many of which were logged subsequent to the hurricane) to assess forest succession. Most of the plots involved successions following the blowdown of white pine on glacial till or outwash soils. From 1940 - 1948, and in 1978 and 1991, tree density and presence/absence of herb and shrub species were tallied. Pioneer species regenerating from seed and advance regeneration of longer-lived species quickly established at the sites; hemlock was the only species successfully regenerating after year 10, and most tree species were present within 2-4 years of the hurricane. By 1978, pioneer species such as gray birch and pin cherry declined or disappeared and red maple, white pine, paper birch and red oak dominated the plots. By 1991, most understory species present before the hurricane had returned, although there was a small group of understory species that apparently were more sensitive to disturbance and did not recover.

• Methods:

  In 1940, Stephen Spurr established 14 plots, either 0.1 ha (10 of the plots) or 0.025 ha (4 of the plots), across the Prospect Hill, Tom Swamp and Slab City tracts of the Harvard Forest. All 14 plots were measured in the 1940s; 13 of the 14 plots were remeasured in 1978 and 1991, as plot A burned and could not be relocated.

  Plot characteristics by soil type and vegetation prior to the hurricane: Glacial till; old-field white pine: Plots A, F, G, H, I, J. Glacial till; immature white pine plantation: Plot B. Glacial till; hardwoods: Plot D. Outwash; white pine and hemlock (described as old-growth by Spurr): Plots C, E, K, L, M. Outwash; selectively cut white pine: Plot N.

  Tree density by species was measured in 1940, 1941, 1942, 1944, 1948, 1978, and 1991. Please note that different size criteria for minimum tree size were used in different years; therefore, stem density by species is not directly comparable between sample years. From 1940-1948, all trees were tallied by species and regeneration type (seedling or sprout). Diameters were not recorded and it is not clear if any minimum size criterion was used. In 1978, all tree stems taller than 1.3m were tallied by species, canopy class and diameter. In 1991, all tree stems with a diameter at 1.4m of greater than 1.0 inch were tallied by species and diameter. Trees in the 1937 forest inventory were tallied by species and 1" diameter classes for stems equaling or exceeding 2 inches dbh.

  Understory species (shrubs, herbs and ferns) were tallied by presence/absence in 1940, 1948, and 1991. To compare community composition between the pre-and post-hurricane forest, Mabry and Korsgren (1991) matched the permanent plots with their corresponding 1937 vegetation inventory stands by overlaying maps, then used the 1937 plot data as an estimate of the pre-hurricane presence of understory species (understory species were listed for each plot) and presence and abundance of overstory trees. Although the 1937 inventory plots and permanent post-hurricane plots measured the same sites, the plots do not correspond exactly and comparisons should be considered an estimate.

  Not all data collected have been transferred to electronic format, but all original paper data sheets are available in the Harvard Forest Archives. Data available electronically include tree density by species for 1937, 1940, 1948, 1978 and 1991 and understory plant presence/absence data by species for 1937, 1940, 1948 and 1991.

• Use:

  This dataset is released to the public and may be freely downloaded. Please keep the designated Contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement. For more information on LTER Network data access and use policies, please see: http://www.lternet.edu/data/netpolicy.html.

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