A rules-based approach for predicting the eastern hemlock component of forests in the northeastern United States

2009 ◽  
Vol 39 (8) ◽  
pp. 1453-1464 ◽  
Author(s):  
Jarrod S. Doucette ◽  
William M. Stiteler ◽  
Lindi J. Quackenbush ◽  
Jeffrey T. Walton
Keyword(s):  
New York ◽  
Forest Cover ◽  
Reference Model ◽  
Basal Area ◽  
Field Measurements ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Slope Aspect ◽  
Landsat Images ◽  
Environmental Indices

The expanding threat of hemlock woolly adelgid (Adelges tsugae Annand) infestation has generated interest in locating eastern hemlock ( Tsuga canadensis (L.) Carr.). Prior studies have incorporated remotely sensed imagery to detect eastern hemlock presence or absence. The goal of this study was to develop methodology to quantify hemlock abundance using software and data accessible to forest managers. Three seasons of Landsat ETM+ scenes served as the imagery basis, whereas simple (slope, aspect, and curvature) and detailed (heat and wetness) environmental indices were extracted from a digital elevation model. Three hundred and forty-nine forest plots representing the typical forest cover found in the Catskill Mountain Region, New York, served as ground reference; model input used the percentage of hemlock basal area for each plot. The models generally underpredicted in plots with substantial hemlock composition, whereas overpredictions mainly occurred in mixed forests that lacked hemlock. Underpredictions negated overpredictions in mixed hemlock deciduous forests resulting in a neutral model. Correlation coefficients ranged from a high of 0.67 for the model created from three Landsat images to a low of 0.01 for the heat and wetness indices model. Although the models were typically within 10% of field measurements, there was no overall benefit in including topographic indices for mapping hemlock abundance.

Feeding by Leucopis argenticollis and Leucopis piniperda (Diptera: Chamaemyiidae) from the western USA on Adelges tsugae (Hemiptera: Adelgidae) in the eastern USA

2017 ◽  
Vol 107 (5) ◽  
pp. 699-704 ◽  
Author(s):  
K. Motley ◽  
N.P. Havill ◽  
A.L. Arsenault-Benoit ◽  
A.E. Mayfield ◽  
D.S. Ott ◽  
...  
Keyword(s):  
New York ◽  
Pacific Northwest ◽  
Adult Stage ◽  
Adelges Tsugae ◽  
Early Summer ◽  
Eastern Hemlock ◽  
Western North America ◽  
The Pacific ◽  
Eastern Usa ◽  
F1 Generation

AbstractLeucopis argenticollis (Zetterstedt) and Leucopis piniperda (Malloch) are known to feed on the lineage of Adelges tsugae Annand that is native to western North America, but it is not known if they will survive on the lineage that was introduced from Japan to the eastern USA. In 2014, western Leucopis spp. larvae were brought to the laboratory and placed on A. tsugae collected in either Washington (North American A. tsugae lineage) or Connecticut (Japanese lineage). There were no significant differences in survival or developmental times between flies reared on the two different adelgid lineages. In 2015 and 2016, western Leucopis spp. adults were released at two different densities onto enclosed branches of A. tsugae infested eastern hemlock (Tsuga canadensis (L.) Carr.) in Tennessee and New York. Cages were recovered and their contents examined 4 weeks after release at each location. Leucopis spp. larvae and puparia of the F1 generation were recovered at both release locations and adults of the F1 generation were collected at the Tennessee location. The number of Leucopis spp. offspring collected increased with increasing adelgid density, but did not differ by the number of adult flies released. Flies recovered from cages and flies collected from the source colony were identified as L.argenticollis and L. piniperda using DNA barcoding. These results demonstrate that Leucopis spp. from the Pacific Northwest are capable of feeding and developing to the adult stage on A. tsugae in the eastern USA and they are able to tolerate environmental conditions during late spring and early summer at the southern and northern extent of the area invaded by A. tsugae in the eastern USA.

scholarly journals When a foundation crumbles: forecasting forest community dynamics following the decline of the foundation speciesTsuga canadensis

2017 ◽  
Author(s):  
Bradley S. Case ◽  
Hannah L. Buckley ◽  
Audrey A. Barker-Plotkin ◽  
David A. Orwig ◽  
Aaron M. Ellison
Keyword(s):  
Tree Species ◽  
Community Dynamics ◽  
Initial Conditions ◽  
Basal Area ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Forest Community ◽  
Forest Communities ◽  
Salvage Logging ◽  
Hemlock Decline

AbstractIn the forests of northeastern North America, invasive insects and pathogens are causing major declines in some tree species and a subsequent reorganization of associated forest communities. Using observations and experiments to investigate the consequences of such declines are hampered because trees are long-lived. Simulation models can provide a means to forecast possible futures based on different scenarios of tree species decline, death, and removal. Such modeling is particularly urgent for species such as eastern hemlock (Tsuga canadensis), a foundation species in many northeast forest regions that is declining due to the hemlock woolly adelgid (Adelges tsugae). Here, we used an individual-based forest simulator, SORTIE-ND, to forecast changes in forest communities in central Massachusetts over the next 200 years under a range of scenarios: a no-adelgid, status-quo scenario; partial resistance of hemlock to the adelgid; adelgid irruption and total hemlock decline over 25 years, adelgid irruption and salvage logging of hemlock trees; and two scenarios of preemptive logging of hemlock and hemlock/white pine.We applied the model to six study plots comprising a range of initial species mixtures, abundances, and levels of hemlock dominance. Simulations indicated that eastern white pine, and to a lesser extent black birch and American beech, would gain most in relative abundance and basal area following hemlock decline. The relative dominance of these species depended on initial conditions and the amount of hemlock mortality, and their combined effect on neighborhood-scale community dynamics. Simulated outcomes were little different whether hemlock died out gradually due to the adelgid or disappeared rapidly following logging. However, if eastern hemlock were to become partially resistant to the adelgid, hemlock would be able to retain its dominance despite substantial losses of basal area. Our modeling highlights the complexities associated with secondary forest succession due to ongoing hemlock decline and loss. We emphasize the need both for a precautionary approach in deciding between management intervention or simply doing nothing in these declining hemlock forests, and for clear aims and understanding regarding desired community- and ecosystem-level outcomes.

scholarly journals Potential of Alternative Tsuga spp. as Landscape Replacements for T. canadensis: Longer-Term Evaluation and Propagation of T. chinensis.

2016 ◽  
Vol 42 (5) ◽  
Author(s):  
Richard Harper ◽  
Paul Weston
Keyword(s):  
United States ◽  
New York ◽  
North America ◽  
Tsuga Canadensis ◽  
Hemlock Woolly Adelgid ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Eastern United States ◽  
Term Evaluation ◽  
Plant Hardiness

Seven species of hemlock (Tsuga spp.)—four from North America and three from Asia—were evaluated in replicated plots in Katonah, New York, United States (USDA Plant Hardiness Zone 6b) as potential replacements for eastern hemlock (Tsuga canadensis), which is gradually being extirpated from landscapes in the eastern United States. by the invasive hemlock woolly adelgid (Adelges tsugae). Trends reported in an earlier study (Weston and Harper 2009) continued but were exaggerated after an additional three years of observation. For example, Chinese hemlock (T. chinensis) continued to show the greatest potential as a replacement for T. canadensis as mortality was very low, overall plant health was exceptional, and tolerance to A. tsugae was robust. Early indicators suggest that T. chinensis may also be readily propagated from hardwood cuttings under appropriate greenhouse conditions. These characteristics suggest that T. chinensis may indeed become a viable replacement for T. canadensis, and a valuable addition to landscapes in the eastern U.S.

scholarly journals India’s Commitments to Increase Tree and Forest Cover: Consequences for Water Supply and Agriculture Production within the Central Indian Highlands

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 959
Author(s):  
Benjamin Clark ◽  
Ruth DeFries ◽  
Jagdish Krishnaswamy
Keyword(s):  
Groundwater Recharge ◽  
Forest Cover ◽  
Hydrological Modeling ◽  
Monsoon Season ◽  
Forest Policy ◽  
Central India ◽  
Field Measurements ◽  
Tree Cover ◽  
Policy Goals ◽  
The Impact

As part of its nationally determined contributions as well as national forest policy goals, India plans to boost tree cover to 33% of its land area. Land currently under other uses will require tree-plantations or reforestation to achieve this goal. This paper examines the effects of converting cropland to tree or forest cover in the Central India Highlands (CIH). The paper examines the impact of increased forest cover on groundwater infiltration and recharge, which are essential for sustainable Rabi (winter, non-monsoon) season irrigation and agricultural production. Field measurements of saturated hydraulic conductivity (Kfs) linked to hydrological modeling estimate increased forest cover impact on the CIH hydrology. Kfs tests in 118 sites demonstrate a significant land cover effect, with forest cover having a higher Kfs of 20.2 mm hr−1 than croplands (6.7mm hr−1). The spatial processes in hydrology (SPHY) model simulated forest cover from 2% to 75% and showed that each basin reacts differently, depending on the amount of agriculture under paddy. Paddy agriculture can compensate for low infiltration through increased depression storage, allowing for continuous infiltration and groundwater recharge. Expanding forest cover to 33% in the CIH would reduce groundwater recharge by 7.94 mm (−1%) when converting the average cropland and increase it by 15.38 mm (3%) if reforestation is conducted on non-paddy agriculture. Intermediate forest cover shows however shows potential for increase in net benefits.

Vegetation dynamics in declining eastern hemlock stands: 9 years of forest response to hemlock woolly adelgid infestation

2006 ◽  
Vol 36 (6) ◽  
pp. 1435-1450 ◽  
Author(s):  
Anne K Eschtruth ◽  
Natalie L Cleavitt ◽  
John J Battles ◽  
Richard A Evans ◽  
Timothy J Fahey
Keyword(s):  
Invasive Plants ◽  
Light Availability ◽  
Hemlock Woolly Adelgid ◽  
Adelges Tsugae ◽  
Eastern Hemlock ◽  
Percent Cover ◽  
Eastern United States ◽  
Transmitted Radiation ◽  
Exotic Invasive ◽  
Exotic Invasive Plants

Hemlock woolly adelgid (HWA; Adelges tsugae Annand) infestations have resulted in the continuing decline of eastern hemlock (Tsuga canadensis (L.) Carrière) throughout much of the eastern United States. In 1994 and 2003, we quantified the vegetation composition and structure of two hemlock ravines in the Delaware Water Gap National Recreation Area. This is the first study to use pre-adelgid disturbance data, annual monitoring of infestation severity, and annual records of hemlock health to assess forest response to HWA infestation. In 2003, 25% of monitored hemlock trees were either dead or in severe decline. Measures of hemlock decline (crown vigor, transparency, density, and dieback) were correlated with HWA infestation severity and changes in light availability over the study period. Average percent total transmitted radiation more than doubled at these sites from 5.0% in 1994 to 11.7% in 2003. The total percent cover of vascular plants increased from 3.1% in 1994 to 11.3% in 2003. Species richness increased significantly, and more species were gained (53) than lost (19) from both ravine floras over the 9-year study period. Though exotic invasive plants were absent from these ravines in 1994, our 2003 resurvey found invasive plants in 35% of the permanent vegetation plots.

scholarly journals State and evolution of the African rainforests between 1990 and 2010

2013 ◽  
Vol 368 (1625) ◽  
pp. 20120300 ◽  
Author(s):  
Philippe Mayaux ◽  
Jean-François Pekel ◽  
Baudouin Desclée ◽  
François Donnay ◽  
Andrea Lupi ◽  
...  
Keyword(s):  
West Africa ◽  
Forest Cover ◽  
Central Africa ◽  
Congo Basin ◽  
Landsat Images ◽  
Deforestation Rate ◽  
Rural And Urban ◽  
Moderate Resolution ◽  
Underlying Causes ◽  
Moderate Resolution Imaging Spectroradiometer

This paper presents a map of Africa's rainforests for 2005. Derived from moderate resolution imaging spectroradiometer data at a spatial resolution of 250 m and with an overall accuracy of 84%, this map provides new levels of spatial and thematic detail. The map is accompanied by measurements of deforestation between 1990, 2000 and 2010 for West Africa, Central Africa and Madagascar derived from a systematic sample of Landsat images—imagery from equivalent platforms is used to fill gaps in the Landsat record. Net deforestation is estimated at 0.28% yr −1 for the period 1990–2000 and 0.14% yr −1 for the period 2000–2010. West Africa and Madagascar exhibit a much higher deforestation rate than the Congo Basin, for example, three times higher for West Africa and nine times higher for Madagascar. Analysis of variance over the Congo Basin is then used to show that expanding agriculture and increasing fuelwood demands are key drivers of deforestation in the region, whereas well-controlled timber exploitation programmes have little or no direct influence on forest-cover reduction at present. Rural and urban population concentrations and fluxes are also identified as strong underlying causes of deforestation in this study.

A comparison of vegetative cover and tree community structure in three forested Adirondack watersheds

1985 ◽  
Vol 15 (5) ◽  
pp. 881-889 ◽  
Author(s):  
Christopher S. Cronan ◽  
Marc R. DesMeules
Keyword(s):  
New York ◽  
Sugar Maple ◽  
New York State ◽  
Basal Area ◽  
Red Maple ◽  
Vegetative Cover ◽  
Cover Type ◽  
Tree Community ◽  
Standing Dead ◽  
Annual Biomass

The Integrated Lake–Watershed Acidification Study (ILWAS) was conducted using three forested watersheds (Panther, Sagamore, and Woods) in the central Adirondack Park of New York State. By comparing the biogeochemical behavior of these watersheds, the ILWAS investigators hoped to elucidate the major ecosystem parameters controlling the fate of strong acids introduced from the atmosphere to lake–watershed systems. The ILWAS vegetation research program was designed to compare the quantitative patterns of forest structure in these midelevation watersheds. Results showed that the ILWAS catchments contain closely related variants of the northern hardwood – spruce – fir complex of the Adirondack region. The dominant tree species in these watersheds are beech (Fagusgrandifolia Ehrh.), red spruce (Picearubens Sarg.), sugar maple (Acersaccharum Marsh.), red maple (Acerrubrum L.), and yellow birch (Betulaalleghaniensis Britt.). On an areal basis, the watersheds contain 57–88% hardwood cover type and 5–29% spruce–fir cover type. Mean live basal area values range from 22 to 30 m2 ha−1 between catchments, while standing dead basal area values range from 4 to 8 m2 ha−1. Mean live stem densities range from 1400 to 1700 stems ha−1. Mean aboveground biomass projections for the tree stratum in the three watersheds range from 143 to 199 Mt ha−1, while estimated aboveground annual biomass increments range from 4.1 to 5.3% of standing biomass.

scholarly journals The Past, Present, and Future of the Hemlock Woolly Adelgid (Adelges tsugae) and Its Ecological Interactions with Eastern Hemlock (Tsuga canadensis) Forests

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 172 ◽  
Author(s):  
Aaron Ellison ◽  
David Orwig ◽  
Matthew Fitzpatrick ◽  
Evan Preisser
Keyword(s):  
Biological Diversity ◽  
Carbon Sources ◽  
Hemlock Woolly Adelgid ◽  
Adelges Tsugae ◽  
Ecosystem Dynamics ◽  
Eastern Hemlock ◽  
Carbon Sinks ◽  
The North ◽  
Spread Dynamics ◽  
Landscape Scales

The nonnative hemlock woolly adelgid is steadily killing eastern hemlock trees in many parts of eastern North America. We summarize impacts of the adelgid on these forest foundation species; review previous models and analyses of adelgid spread dynamics; and examine how previous forecasts of adelgid spread and ecosystem dynamics compare with current conditions. The adelgid has reset successional sequences, homogenized biological diversity at landscape scales, altered hydrological dynamics, and changed forest stands from carbon sinks into carbon sources. A new model better predicts spread of the adelgid in the south and west of the range of hemlock, but still under-predicts its spread in the north and east. Whether these underpredictions result from inadequately modeling accelerating climate change or accounting for people inadvertently moving the adelgid into new locales needs further study. Ecosystem models of adelgid-driven hemlock dynamics have consistently forecast that forest carbon stocks will be little affected by the shift from hemlock to early-successional mixed hardwood stands, but these forecasts have assumed that the intermediate stages will remain carbon sinks. New forecasting models of adelgid-driven hemlock decline should account for observed abrupt changes in carbon flux and ongoing and accelerating human-driven land-use and climatic changes.

scholarly journals LAND COVER DYNAMICS AND LANDSCAPE STRUCTURE IN THE AREA SURROUNDING WATER RESERVOIRS, MOUNTAINOUS REGION OF RIO DE JANEIRO

FLORESTA ◽  
2020 ◽  
Vol 50 (4) ◽  
pp. 1808
Author(s):  
Lucas De Siqueira Cardinelli ◽  
José Marinaldo Gleriani ◽  
Sebastião Venâncio Martins
Keyword(s):  
Land Cover ◽  
Landscape Structure ◽  
Rio De Janeiro ◽  
Forest Cover ◽  
Water Area ◽  
Mountainous Region ◽  
Water Reservoirs ◽  
Landsat Images ◽  
Surrounding Water ◽  
Land Cover Dynamics

The aim of this study is to evaluate land cover dynamics and landscape structure in the area surrounding two water reservoirs built-in 2009 for energy production, in the mountainous region of the State of Rio de Janeiro (Serra Fluminense). The analysis was developed through the interpretation of Landsat images from 2003, 2009, and 2013, considering the following land cover classes: early successional forest, mid successional forest, pasture, pasture with shrubs and trees, geological outcrop, urban area, and water area. We used thematic maps to determine landscape metrics of size and proximity in the reservoirs catchment area and the Permanent Preservation Area (PPA). At catchment level, pasture was predominant, a consequence of the extensive livestock production carried out in the whole watershed. During the evaluated period, the forest area remained consistent, however, fragmented in many small patches of mid successional forest. The average patch area of mid successional forest is three times the size of the early successional forest patches. For neither forest land cover classes, no significant variations through time in area or isolation were identified. On the PPA, an overall reduction of the forest cover was registered before the construction of the reservoir. However, from 2009 to 2013, after the enclosure of PPA areas, the forest cover increased 35% via assisted natural regeneration, suggesting a high potential for cost-effective restoration in the region.

scholarly journals Forests in Flux: The Effects of Demographic Change on Forest Cover in New England and New York

2016 ◽  
Author(s):  
Mark Ducey ◽  
Kenneth Johnson ◽  
Ethan Belair ◽  
Miranda Mockrin
Keyword(s):  
New York ◽  
New England ◽  
Demographic Change ◽  
Forest Cover
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