Do natural disturbance regimes provide realistic guidelines for managing early-successional habitats in New England forests?

Major forest types in northern U.S. Lull (1968)

~ 1880

~ 1930 >50% of forest vertebrates utilize early-successional stands

Obligate users RELATIVE USE AGE OF STAND 0.5

Golden-winged warbler USGS

FOREST CLEARING FARM ABANDONMENT FOREST MATURATION Relative abundance of early-successional habitats RETURN TO PRE-COLUMBIAN CONDITIONS ?

How much was there?

source: Harvard Forest

Methods to Estimate Natural Disturbance Regimes Lorimer and White (2003) Sedimentary pollen and charcoal Presettlement land surveys Descriptions by early naturalists Reconstruction of disturbance history in old-growth stands Modern records and aerial photos Computer models

Large-scale fires infrequent in New England, ~800-1,200 years 1790 survey in NY found that 1% of landscape burned or open.

Small-scale wind storms: kill one to several trees. In eastern U. S., %/year of all forests are affected by wind throw. At any time, 5-50% of a forest may be affected.

Large-scale wind storms: hurricanes or tornadoes at irregular intervals (1635, 1788, 1815, 1938, and 1944) hurricane affected >240,000 ha in New England Boose et al. (2001)

85 yr 150 yr 380 yr >380 yr Approximate return interval of damaging (F2) hurricanes in New England. Boose et al. (2001)

Wilson 2005 Lumber Exports (Wilson 2005) vs Witness Trees Projections (Lorimer 1977): very different estimates of the prominence of white pine (>10x), indicating a large difference in the frequency and scale of disturbance in these forests.

Northern Hardwoods seedling/sapling (1-15 yrs): 1-3% young pole (15-30 yrs): 1-3% 2-6% Pitch Pine- Scrub Oak seedling/sapling: 10-30% young pole: 10-30% 20-60% (Lorimer and White 2003)

Trani et al. (2001) 9% 4% Early-successional forests in the eastern U.S.

What About Biotic Disturbances?

Contemporary Herbivores

flooded forest pond wet meadow shrubs forest

Open water areas created by beaver dams on the Kabetogama Peninsula, northern MN. 1940: 1% of area 1986: 13% of area Johnston and Naiman (1990) How large an area affected?

Northern Hardwoods seedling/sapling 1-3% young pole 1-3% beaver flowages ~3.5% (Gotie and Jenks 1982) 5-11% (Lorimer and White 2003)

Even if we can accurately estimate HRNV, are these values relevant in contemporary landscapes?

40/mi /mi 2 POPULATION DENSITY

Hoving (2001) Road Density in the Northeast

COMPOSITION (%) RACCOON/CANID TRACKS CANIDS RACCOONS LANDSCAPE FOR DEV AGR

2.5 ha 5 ha Winter mortality: 69%35% Patches

OCTNOVDECJANFEBMARAPRMAY FOOD QUALITY LARGE PATCHES SMALL PATCHES THRESHOLD? CONDITION-SENSITIVE PREDATION

9 JAN 16 JAN23 JAN 30 JAN 6 FEB 13 FEB20 FEB27 FEB 6 MAR 13 MAR 20 MAR27 MAR 3 APR 10 APR UN:C RATIO

New approaches needed to provide habitat

Parcelization or Fragmentation potential to mimic natural disturbances restoration of shrublands/ modified disturbance regime (sliding scale) modified disturbances (large and clustered/connected) limited extreme Forest Age young old

MANAGING INDUCED METAPOPULATIONS: may require deviating from HRNV ME NH VT NY MA CT RI

DESCRIBING HABITAT DISTURBANCES SizeFrequencyIntensity

Do natural disturbance regimes provide realistic guidelines for managing early-successional habitats in New England forests?

Human-generated disturbances

Pisgah Forest in southwestern New Hampshire three years after 1938 hurricane.