Characterizing Canopy Openness Across Large Forested Landscapes Using Spherical Densiometer and Smartphone Hemispherical Photography

2021 ◽  
Author(s):  
Katie L Beeles ◽  
Jordon C Tourville ◽  
Martin Dovciak
Keyword(s):  
United States ◽  
Large Range ◽  
Forest Type ◽  
High Elevation ◽  
Canopy Openness ◽  
Hemispherical Photography ◽  
Forest Types ◽  
Northeastern United States ◽  
Closed Canopy ◽  
The Right

Abstract Canopy openness is an important forest characteristic related to understory light environment and productivity. Although many methods exist to estimate canopy openness, comparisons of their performance tend to focus on relatively narrow ranges of canopy conditions and forest types. To address this gap, we compared two popular approaches for estimating canopy openness, traditional spherical densiometer and modern smartphone hemispherical photography, across a large range of canopy conditions (from closed canopy to large gaps) and forest types (from low-elevation broadleaf to high-elevation conifer forests) across four states in the northeastern United States. We took 988 field canopy openness measurements (494 per instrument) and compared them across canopy conditions using linear regression and t-tests. The extensive replication allowed us to quantify differences between the methods that may otherwise go unnoticed. Relative to the densiometer, smartphone photography overestimated low canopy openness (<10%) but it underestimated higher canopy openness (>10%), regardless of forest type. Study Implications We compared two popular ways of measuring canopy openness (smartphone hemispherical photography and spherical densiometer) across a large range of forest structures encountered in the northeastern United States. We found that, when carefully applied, the traditional spherical densiometer can characterize canopy openness across diverse canopy conditions (including closed canopies) as effectively as modern smartphone canopy photography. Although smartphone photography reduced field measurement time and complexity, it was more susceptible to weather than the densiometer. Although selection of the right method depends on study objectives, we provide a calibration for these two popular methods across diverse canopies.

Habitat Use by Arboreal Mammals along an Environment Gradient in North-eastern Victoria

1991 ◽  
Vol 18 (2) ◽  
pp. 125 ◽  
Author(s):  
AF Bennett ◽  
LF Lumsden ◽  
JSA Alexander ◽  
PE Duncan ◽  
PG Johnson ◽  
...  
Keyword(s):  
Habitat Use ◽  
Environmental Gradient ◽  
Forest Type ◽  
High Elevation ◽  
Annual Rainfall ◽  
Distributional Pattern ◽  
Forest Types ◽  
Phascolarctos Cinereus ◽  
North Eastern ◽  
Arboreal Mammal

A total of 1487 observations of nine species of arboreal mammal, Acrobates pygmaeus, Phascolarctos cinereus, Petauroides volans, Petaurus australis, P. breviceps, P. norfolcensis, Pseudocheirusperegrinus, Trichosurus caninus and T. vulpecula, were made during surveys of the vertebrate fauna of northeastern Victoria. Habitat use by each species was examined in relation to eight forest types that occur along an environmental gradient ranging from sites at high elevation with a high annual rainfall, to sites on the dry inland and riverine plains. Arboreal mammals were not evenly distributed between forest types. Three species (P. australis, P. volans and T. caninus) were mainly associated with moist tall forests; two species (P. norfolcensis and T. vulpecula) were primarily associated with drier forests and woodlands of the foothills; the remaining three species (A. pygmaeus, P. breviceps and P. peregrinus) occurred widely throughout the forests. The composition of the arboreal mammal assemblage changed along the environmental gradient, but species displayed gradual changes in abundance with forest type rather than marked discontinuities in distributional pattern. The highest overall frequencies of occurrence of arboreal mammals were in forests typically dominated by a mixture of eucalypt species. The position at first sighting of an animal, and the relative height in the forest stratum, were used to describe the micro-habitats utilised. In general, the microhabitats occupied by each species are consistent with the distribution of their known food resources.

A novel ice storm manipulation experiment in a northern hardwood forest

2012 ◽  
Vol 42 (10) ◽  
pp. 1810-1818 ◽  
Author(s):  
Lindsey E. Rustad ◽  
John L. Campbell
Keyword(s):  
United States ◽  
Forest Canopy ◽  
Forest Ecosystems ◽  
Hardwood Forest ◽  
Canopy Openness ◽  
Northern Hardwood Forest ◽  
Ice Storm ◽  
Northeastern United States ◽  
Northern Hardwood ◽  
Ice Storms

Ice storms are an important natural disturbance within forest ecosystems of the northeastern United States. Current models suggest that the frequency and severity of ice storms may increase in the coming decades in response to changes in climate. Because of the stochastic nature of ice storms and difficulties in predicting their occurrence, most past investigations of the ecological effects of ice storms across this region have been based on case studies following major storms. Here we report on a novel alternative approach where a glaze ice event was created experimentally under controlled conditions at the Hubbard Brook Experimental Forest, New Hampshire, USA. Water was sprayed over a northern hardwood forest canopy during February 2011, resulting in 7–12 mm radial ice thickness. Although this is below the minimum cutoff for ice storm warnings (13 mm of ice) issued by the US National Weather Service for the northeastern United States, this glaze ice treatment resulted in significant canopy damage, with 142 and 218 g C·m–2 of fine and coarse woody debris (respectively) deposited on the forest floor, a significant increase in leaf-on canopy openness, and increases in qualitative damage assessments following the treatment. This study demonstrates the feasibility of a relatively simple approach to simulating an ice storm and underscores the potency of this type of extreme event in shaping the future structure and function of northern hardwood forest ecosystems.

scholarly journals Spatiotemporal Invasion Severity of Chinese Tallow (Triadica sebifera) and Invasibility of Forest Types in Southern US Forestlands

2021 ◽  
Author(s):  
Sunil Nepal ◽  
W Keith Moser ◽  
Zhaofei Fan
Keyword(s):  
United States ◽  
Forest Type ◽  
Coastal Region ◽  
Pinus Palustris ◽  
The United States ◽  
Slash Pine ◽  
Forest Types ◽  
Triadica Sebifera ◽  
Chinese Tallow ◽  
Severity Class

Abstract Quantifying invasion severity of nonnative invasive plant species is vital for the development of appropriate mitigation and control measures. We examined more than 23,250 Forest Inventory and Analysis (FIA) plots from the southern coastal states of the United States to develop an alternative method to classify and map the invasion severity of Chinese tallow (Triadica sebifera). Remeasured FIA plot-level data were used to examine the spatiotemporal changes in the presence probability and cover percentage of tallow. Four invasion severity classes were identified by using the product of presence probability and cover percentage. Chinese tallow invasion severity increased over time with 90 and 123 counties being classified into the highest severity class for the first and second measurement, respectively. Further, the invasibility of major forest-type groups by severity class was examined using the product of the county-level mean presence probability and mean cover percentage of Chinese tallow as a proxy of invasibility. Longleaf/slash pine (Pinus palustris/P. elliottii) forests were highly resilient to the Chinese tallow invasion. In contrast, elm/ash/cottonwood (Ulmus spp./Fraxinus spp./Populus deltoides) and oak/gum/cypress (Quercus spp./Nyssa spp./Taxodium spp.) forest-type groups were vulnerable to invasion. Study Implications: In the southern United States forestland, differences in invasion severity and vulnerability of forest types to Chinese tallow invasion have been observed across time and space. Our findings provide insight into spatial variations in the severity of Chinese tallow invasion and the relative susceptibility of different forest-type groups in the region to inform monitoring and management of this invasive species. High invasion severity occurs in the lower Gulf of Mexico coastal region of Texas, Louisiana, and Mississippi and the Atlantic coastal region of South Carolina and Georgia, with the longleaf/slash pine and oak/gum/cypress forest-type groups being most susceptible to Chinese tallow invasion. Based on these results, we recommend that management efforts be tailored to the different invasion severity classes. Forests in the high-severity class need a management program coordinated across different agencies and landowners to curb the increase of tallow populations to prevent stand replacing risks. The monitoring of Chinese tallow spread should focus on longleaf/slash pine, loblolly/shortleaf pine, and oak/gum/cypress groups, because the spread rate was higher in these forest-type groups. A better use of scarce resources could be to treat lands in the moderate- and low-severity classes to reduce the propagule pressure levels and post-invasion spread. For those counties with a minimal-severity condition, early detection and eradiction measures should be taken in a timely maner to prevent tallow from invading noninvaded neighboring counties. Managers may be able to treat a larger area of these lands for a given investment compared with lands already severely invaded.

Pleistocene refuge areas and postglacial dispersal of copepods of the northeastern United States

1995 ◽  
Vol 52 (10) ◽  
pp. 2197-2210 ◽  
Author(s):  
Richard S. Stemberger
Keyword(s):  
United States ◽  
Coastal Plain ◽  
Distribution Patterns ◽  
High Elevation ◽  
Atlantic Coastal Plain ◽  
Temporary Ponds ◽  
Mississippi Valley ◽  
Northeastern United States ◽  
Freshwater Copepods ◽  
Atlantic Coastal

The distribution of common freshwater copepods of the northeastern United States has a marked association with major meltwater drainage systems and coastal marine submergence zones formed during the retreat of the Wisconsinan ice sheet. Postglacial dispersal routes inferred from the deglaciation chronology indicate that zooplankton could have come from several major Pleistocene refuges in the Mississippi Valley, Appalachian Plateaus, and mid-Atlantic Coastal Plain, and from northern locations on the Atlantic Coastal Plain. Contemporary distribution patterns suggest that some species of copepods dispersed primarily in surface waters during advances and retreats of continental glaciers. These include species of the calanoid Skistodiaptomus and the cyclopoid Diacyclops thomasi that occur in coastal lowlands and in lower elevation lakes in mountainous areas that could be flooded by retreating ice-front lakes. There is little evidence, except for inadvertent introductions through human activities, that these species have expanded beyond their original postglacial dispersal boundaries. In contrast, other calanoid and cyclopoid species were widely distributed and are dominant in high-elevation lakes and lowland lakes behind mountain barriers unreachable by species dependent on water transport. These species commonly occur in permanent and temporary ponds and may produce dormant stages that are readily dispersed.

Assessment of Disturbances across Forest Inventory Plots in the Southeastern United States for the Period 1995–2018

2019 ◽  
Vol 66 (2) ◽  
pp. 242-255 ◽  
Author(s):  
Santosh K Ojha ◽  
Kozma Naka ◽  
Luben D Dimov
Keyword(s):  
United States ◽  
Coastal Plain ◽  
Forest Inventory ◽  
Stand Structure ◽  
Forest Type ◽  
Southeastern United States ◽  
Forest Types ◽  
Forest Inventory And Analysis ◽  
Silvicultural Treatments ◽  
Structure And Functions

Abstract Disturbances of varying frequency and intensity shape the species composition, stand structure, and functions of forests. This study assessed the frequency and distribution of disturbances caused by eight agents (insects, diseases, fire, animals, weather, other vegetation, human, and unknown) in the forests of the southeastern United States from 1995 to 2018. We used data from 88,722 inventory measurements of 33,531 plots from the USDA Forest Inventory and Analysis database to assess disturbance among different forest types and to different canopy strata. Disturbances were detected in approximately 14 percent of the plots, located mostly in pine-dominated forest types. Fire was the most frequent disturbance agent (occurring 6 percent of the time), followed by weather and animal agents. The agents that caused the highest mortality rate during the period for saplings were silvicultural treatments (8.6 percent), other vegetation (5.6 percent), and fire (4.4 percent), whereas for trees they were silvicultural treatments (9.8 percent), weather (1.9 percent) and insects (1.7 percent). The forest type that appeared to have been most affected by disturbances was longleaf–slash pine of the Coastal Plain. These results are useful for understanding the spatiotemporal distribution of disturbance events in different southeastern forest types and locations and for guiding forest management activities to mitigate potential impacts.

Spatial ecology and resource selection of a high-elevation American marten (Martes americana) population in the northeastern United States

2016 ◽  
Vol 94 (3) ◽  
pp. 169-180 ◽  
Author(s):  
A.P.K. Sirén ◽  
P.J. Pekins ◽  
M.J. Ducey ◽  
J.R. Kilborn
Keyword(s):  
United States ◽  
Home Range ◽  
Resource Selection ◽  
High Elevation ◽  
Home Range Size ◽  
Range Size ◽  
Martes Americana ◽  
Home Ranges ◽  
Northeastern United States ◽  
Rugged Terrain

High-elevation forests that contain mature, closed canopy stands are considered important habitat for American martens (Martes americana (Turton, 1806)) in the northeastern United States. To investigate this hypothesis, we monitored 15 radio-collared martens over a 2-year period and measured spatial use, as well as second- and third-order resource selection, from 33 seasonal home ranges and 889 telemetry locations. The population was composed primarily of adults that had small home-range size with average seasonal fidelity. During leaf-off seasons, martens selected against regenerating forest at both scales and selected for mixedwood and softwood forests and areas with rugged terrain within home ranges. Second-order selection was less pronounced during leaf-on seasons, yet martens exhibited greater selection for hardwood forest and areas with rugged terrain within home ranges. Home-range size was correlated positively with the amount of regenerating forest and body-condition index scores were lower during winter, indicating that these spatial and temporal attributes were influential. Although martens utilized low-elevation forest with extensive timber harvesting, contiguous, mature, and rugged high-elevation forest was used preferentially during winter. Land managers should minimize disturbance of montane ecosystems to ensure population viability for martens and other boreal forest species along distributional edges.

scholarly journals Development and Evaluation of High-Resolution Climate Simulations over the Mountainous Northeastern United States

2016 ◽  
Vol 17 (3) ◽  
pp. 881-896 ◽  
Author(s):  
Jonathan M. Winter ◽  
Brian Beckage ◽  
Gabriela Bucini ◽  
Radley M. Horton ◽  
Patrick J. Clemins
Keyword(s):  
United States ◽  
High Resolution ◽  
Air Temperature ◽  
Climate Models ◽  
Global Climate ◽  
Probability Distributions ◽  
New York State ◽  
High Elevation ◽  
Global Climate Models ◽  
Northeastern United States

Abstract The mountain regions of the northeastern United States are a critical socioeconomic resource for Vermont, New York State, New Hampshire, Maine, and southern Quebec. While global climate models (GCMs) are important tools for climate change risk assessment at regional scales, even the increased spatial resolution of statistically downscaled GCMs (commonly ~⅛°) is not sufficient for hydrologic, ecologic, and land-use modeling of small watersheds within the mountainous Northeast. To address this limitation, an ensemble of topographically downscaled, high-resolution (30″), daily 2-m maximum air temperature; 2-m minimum air temperature; and precipitation simulations are developed for the mountainous Northeast by applying an additional level of downscaling to intermediately downscaled (⅛°) data using high-resolution topography and station observations. First, observed relationships between 2-m air temperature and elevation and between precipitation and elevation are derived. Then, these relationships are combined with spatial interpolation to enhance the resolution of intermediately downscaled GCM simulations. The resulting topographically downscaled dataset is analyzed for its ability to reproduce station observations. Topographic downscaling adds value to intermediately downscaled maximum and minimum 2-m air temperature at high-elevation stations, as well as moderately improves domain-averaged maximum and minimum 2-m air temperature. Topographic downscaling also improves mean precipitation but not daily probability distributions of precipitation. Overall, the utility of topographic downscaling is dependent on the initial bias of the intermediately downscaled product and the magnitude of the elevation adjustment. As the initial bias or elevation adjustment increases, more value is added to the topographically downscaled product.

Termite assemblages in two distinct montane forest types at 1000 m elevation in the Maliau Basin, Sabah

2000 ◽  
Vol 16 (2) ◽  
pp. 271-286 ◽  
Author(s):  
David T. Jones
Keyword(s):  
Relative Abundance ◽  
Forest Type ◽  
Montane Forest ◽  
Primary Forest ◽  
Similar Species ◽  
Forest Types ◽  
Open Canopy ◽  
Closed Canopy ◽  
Lowland Forests ◽  
Belt Transect

Termites were surveyed at an altitude of 1000 m in Maliau Basin, Sabah (Borneo), in two primary forest habitats: lower montane forest and stunted facies of upper montane forest. Soil, wood, litter, termite nests, and arboreal microhabitats up to a height of 2 m above ground were sampled using a belt transect protocol. Two transects were run in each forest type. The upper montane forest transects collected 11 and 13 species, compared with 15 and 19 in the lower montane forest transects. With the addition of species records from casual sampling (conducted with roughly equal effort in each forest type), totals of 18 species were found in the upper montane forest, and 34 species in the lower montane forest. Similar species richness and relative abundance of wood-feeding termites were found in both forest types. However, the lower montane forest had greater richness and relative abundance of species that feed on soil and extremely decayed soil-like wood. This difference is attributed mainly to (i) the well developed, organic-rich soils of the lower montane forest being more suitable for soil-dwelling and mound-building termites compared with the upper montane forest which has sandy soils with a thick covering of peat, and (ii) the low-stature and open canopy of the upper montane forest creates microclimatic conditions which are adverse for soil-feeding termites compared with the high, closed canopy in the lower montane forest. As expected, comparisons with similar studies in lowland forests in Southeast Asia confirmed that the upland forests are relatively depauperate.

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