Anisotropic spread of hemlock woolly adelgid in the eastern United States

Morin, Randall S.; Liebhold, Andrew M.; Gottschalk, Kurt W.

doi:10.1007/s10530-008-9420-1

Cited by 80 publications

(75 citation statements)

References 20 publications

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“…Morin et al (2009) estimates that HWA is spreading to the north at a rate of between 9 and 10.6 miles per year. However, cold winter temperatures can cause considerable adelgid mortality and trigger dramatic population declines (Skinner et al 2003).…”

Section: What This Meansmentioning

confidence: 99%

Forests of Vermont and New Hampshire 2012

Morin¹,

Barnett²,

Butler³

et al. 2015

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The first full remeasurement of the annual inventory of the forests of Vermont and New Hampshire was completed in 2012 and covers nearly 9.5 million acres of forest land, with an average volume of nearly 2,300 cubic feet per acre. The data in this report are based on visits to 1,100 plots located across Vermont and 1,091 plots located across New Hampshire. Forest land is dominated by the maple/beech/birch forest-type group, which occupies 60 percent of total forest land area. Of the forest land, 64 percent consists of large diameter trees, 27 percent contains medium diameter trees, and 9 percent contains small diameter trees. The volume of growing stock on timberland has continued to increase since the 1980s and currently totals nearly 19 billion cubic feet. The average annual net growth of growing stock on timberland from 2007 to 2012 is approximately 380 million cubic feet per year. Important species compositional changes include increases in the number of red maple trees and American beech saplings which coincide with decreases in the number of eastern white pine and sugar maple trees as well as eastern white pine and northern red oak saplings. Additional information is presented on forest attributes, land use change, carbon, timber products, species composition, regeneration, and forest health. Detailed information on forest inventory methods and data quality estimates is included on the DVD accompanying this report. Tables of population estimates and a glossary are also included. AcknowledgmentsThe authors would like to thank inventory crew members from Vermont and New Hampshire for their help:

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Section: What This Meansmentioning

confidence: 99%

Forests of Vermont and New Hampshire 2012

Morin¹,

Barnett²,

Butler³

et al. 2015

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“…Morin et al (2009) estimated that HWA is spreading at a rate of between 6.0 and 9.0 miles/year in the northwest and north directions. However, cold winter temperatures can cause considerable mortality and trigger dramatic population declines (Skinner et al 2003).…”

Section: What This Meansmentioning

confidence: 99%

New York Forests, 2012

Widmann¹,

Crawford²,

Kurtz³

et al. 2015

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This report summarizes the second annual inventory of New York's forests, conducted in 2008-2012. New York's forests cover 19.0 million acres; 15.9 million acres are classified as timberland and 3.1 million acres as reserved and other forest land. Forest land is dominated by the maple/beech/ birch forest-type group that occupies more than half of the forest land. The sound wood volume on timberland has been rising and is currently 37.4 billion cubic feet, enough to produce saw logs equivalent to 93.7 billion board feet. On timberland, the average annual growth in volume of live trees outpaced removals by a ratio of 2.1:1. The net change in volume averaged 1.1 percent per year. This report includes additional information on forest attributes, land use, forest fragmentation, forest ownership, forest health indicators, timber products, statistics, and quality assurance of data collection. Detailed information on forest inventory methods and data quality are available online at http://dx

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“…Better knowledge of the regional, landscape, and site factors that control the impact of HWA and the subsequent response of forest ecosystems to its damage across a range of spatial and temporal scales is necessary to forecast future dynamics of forest change associated with this pest. Since it entered Richmond, VA in the early 1950s (Souto et al 1996), HWA has spread via wind, birds, deer and humans rapidly to the north and recently to the more scattered stands in the south (McClure 1990, Morin et al 2009). Current rates of HWA dispersal are estimated to be between 8 and 13 km yr À1 (Evans and Gregoire 2007).…”

Section: Introductionmentioning

confidence: 99%

A foundation tree at the precipice:Tsuga canadensishealth after the arrival ofAdelges tsugaein central New England

et al. 2012

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Abstract. Hemlock (Tsuga canadensis) plays a unique role in Eastern forests, producing distinctive biogeochemical, habitat, and microclimatic conditions and yet has begun a potentially irreversible decline due to the invasive hemlock woolly adelgid (Adelges tsugae; HWA) that causes foliar damage, crown loss, and mortality of host trees. Understanding the regional, landscape, site, and stand factors influencing HWA spread and impact is critical for predicting future landscape dynamics and directing effective management. Using aerial photographs, we documented hemlock distribution throughout central Massachusetts and subsampled 123 stands to examine the spatial pattern of HWA and its impact on tree vigor and mortality since its arrival in 1989. In the study region, over 86,000 ha of hemlock forest were mapped in 5,127 stands. White pine (Pinus strobus), red oak (Quercus rubra), red maple (Acer rubrum), and black birch (Betula lenta) were common overstory associates. Hemlock abundance increased from south to north, commonly on western and northwestern slopes. Average stand size was 55 ha, overstory basal area ranged from 23 to 55 m 2 ha À1 and overstory stem densities averaged 993 ha À1 .By 2004, 40% of sampled stands were infested, but most stands remained in good health overall; only 8 stands contained high HWA densities and only two had lost .50% overstory hemlock. Out of fifteen stand and landscape predictor variables examined, only latitude and winter climate variables were related to HWA density. Cold temperatures appear to be slowing the spread and impact of HWA at its northern extent as HWA infestation intensity and hemlock mortality and vigor were significantly correlated with average minimum winter temperature. Contrary to predictions, there was no regional increase in hemlock harvesting. The results suggest that regional HWA-hemlock dynamics are currently being shaped more by climate than by a combination of landscape and social factors. The persistence and migration of HWA continues to pose a significant threat regionally, especially in the northern portion of the study area, where hemlock dominates many forests.

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Anisotropic spread of hemlock woolly adelgid in the eastern United States

Cited by 80 publications

References 20 publications

Forests of Vermont and New Hampshire 2012

Forests of Vermont and New Hampshire 2012

New York Forests, 2012

A foundation tree at the precipice:Tsuga canadensishealth after the arrival ofAdelges tsugaein central New England

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