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NORTHEAST TEMPERATE NETWORK
FOREST HEALTH MONITORING REPORT
2006-2009
Natural Resource Report NPS/NETN/NRR—2010/206
Kate M. Miller
Northeast Temperate Network
Acadia National Park
Bar Harbor, ME 04609
Geri L. Tierney
Department of Environmental & Forest Biology
SUNY College of Environmental Science & Forestry
Syracuse, NY 13210
Brian R. Mitchell
Northeast Temperate Network
54 Elm Street
Woodstock, VT 05091
June 2010
U.S. Department of the Interior
National Park Service
Natural Resource Program Center
Fort Collins, Colorado
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Executive Summary
In 2006 the Northeast Temperate Network (NETN) Inventory and Monitoring Program began implementing a long-term forest monitoring program to assess status and trends in forest composition, structure and function within ten national park units: Acadia National Park (ACAD), Marsh-Billings-Rockefeller National Historical Park (MABI), Minute Man National Historical Park (MIMA), Morristown National Historical Park (MORR), Roosevelt-Vanderbilt National Historic Sites (ROVA), Saint-Gaudens National Historic Site (SAGA), Saratoga National Historical Park (SARA), and Weir Farm National Historic Site (WEFA). Roosevelt-Vanderbilt National Historic Sites includes Eleanor Roosevelt National Historic Site (ELRO), Home of Franklin D. Roosevelt National Historic Site (HOFR), and Vanderbilt Mansion National Historic Site (VAMA). To date, NETN has established and sampled 344 permanent forest plots. In 2010, NETN will begin resampling plots in ACAD, MABI, MIMA, SAGA and SARA.
This report summarizes metrics of ecological integrity for ACAD, ELRO/HOFR, MORR, VAMA, and WEFA, and examines forest composition and structure for all NETN parks sampled from 2006-2009. The ecological integrity metrics were calculated from data collected in 2007 and 2009 for ELRO/HOFR, MORR, VAMA, and WEFA and data collected from 2006-2009 for ACAD. Ecological integrity metrics include structural stage distribution, coarse woody debris (CWD) ratio, snag abundance, tree regeneration, tree condition and forest pests, invasive exotic plants and soil chemistry. Forest composition and structure summaries are based on density (stems/ha), and compare the composition of the forest canopy to the seedling and sapling strata.
Of the five parks rated herein, all except ACAD rated "Good" for forest structural stage distribution. A "Good" rating for this metric indicates that the distribution of forest successional stages is currently within the range of natural variation as we understand it. This range varies considerably across the network with much lower percentages of mature and late-successional forest expected in the oak-dominated forests of the more southern parks than in the northern hardwood and mixed forests of ACAD, MABI and SAGA. ACAD rated “Caution” overall for this metric. Given that the majority of ACAD's forests are second-growth and just beginning to reach maturity, it will be some time before ACAD can be rated "Good" for this metric.
The condition of canopy trees rated "Good" or "Caution" for all NETN parks. In most cases, "Caution" ratings were the result of higher than expected herbivory and/or chlorosis of the foliage. Hemlock woolly adelgid and elongate hemlock scale were detected on plots in ELRO/HOFR, VAMA, and WEFA, and while in route to a plot in MORR. Balsam woolly adelgid was detected in several plots in ACAD. Beech bark disease was most severe in ACAD.
Invasive species of concern were present in all the parks, though few were present in ACAD. All park subunits in ACAD were rated "Good" for this metric; indicator invasive species were only detected in one of 169 plots. Invasive species are most frequent in MORR and VAMA. Both MORR and VAMA were rated "Significant Concern," averaging over four indicator invasive species per plot. ELRO/HOFR and WEFA were not far behind, averaging roughly three indicator invasives per plot.
ROVA units rated fairly well for coarse woody debris (CWD) ratio and snag abundance. VAMA snag abundance and CWD ratio received "Good" ratings. ELRO/HOFR rated "Good" for CWD ratio and "Caution" for snag abundance. At the park level, ACAD rated "Caution" for CWD ratio and "Good" for snag abundance. MORR, WEFA and MABI were all rated "Caution" for CWD ratio, and "Significant Concern" for snag abundance.
Soil chemistry results differed between the two indicators (C:N and Ca:Al ratios), and all parks except WEFA had a "Good" rating for at least one of the ratios. Soil acidification is potentially a problem in ACAD and WEFA. Excess nitrogen may be an issue in MORR, ROVA and WEFA.Atmospheric deposition may be of greatest concern in WEFA, which rated "Significant Concern" for the C:N ratio and "Caution" for the Ca:Al ratio.
Both the ecological integrity regeneration metric and the composition and structure analyses indicate tree regeneration densities in MORR and WEFA are well below levels required to adequately restock the forest canopy, and low regeneration may also be a problem in ELRO/HOFR.
Compositional differences between the forest canopy (current forest) and seedling and sapling strata (future forest) were detected for several parks:
• Oak (Quercus spp.) regeneration is rare in ELRO/HOFR, MORR, SARA, VAMA, and WEFA
• Tulip poplar (Liriodendron tulipifera) regeneration is absent in ELRO/HOFR, MORR, VAMA, and WEFA
• Hickory (Carya spp.) regeneration is sparse in MORR, SARA, and WEFA
• Hemlock (Tsuga canadensis) regeneration is low in ELRO/HOFR and SAGA
• Beech (Fagus grandifolia), white ash (Fraxinus americana), and red maple
(Acer rubrum) were more abundant in the seedling and sapling layers than in the canopy of ELRO/HOFR, MORR, SARA, VAMA, and WEFA
The presence of Norway maple (Acer platanoides) seedlings, saplings and trees in ELRO/HOFR, MIMA and VAMA is an important management concern. Norway maple can outcompete native maple species, and has the potential to replace native maples in both the understory and canopy.
These results suggest that forest conditions in most NETN parks could benefit from management actions such as reduction of white-tailed deer populations (MORR and WEFA), eradication and/or control of invasive species (all parks), and early detection
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