scholarly journals Testing the Ability of Airborne LiDAR to Measure Forage Resources for Wild Ungulates in Conifer Forests

2019 ◽  
Vol 117 (5) ◽  
pp. 492-503 ◽  
Author(s):  
Iver T Hull ◽  
Lisa A Shipley
Keyword(s):  
Food Resource ◽  
Canopy Cover ◽  
Laser Pulses ◽  
Understory Vegetation ◽  
Airborne Lidar ◽  
Forest Understory ◽  
Conifer Forests ◽  
Vegetation Density ◽  
Wild Ungulates ◽  
Vegetation Biomass

Abstract Vegetation in the forest understory is a key food resource for wild ungulates like deer (Odocoileus spp.) because the amount of nutritious forage influences animal productivity and density. Therefore, measuring the abundance of understory vegetation available to wildlife populations is often a key objective for wildlife managers. Field-based methods for measuring understory vegetation across remote landscapes are time- and resource-intensive, so we compared estimates of understory vegetation density derived from airborne light detection and ranging (LiDAR) returns with vegetation biomass sampled directly on 65 field plots across 4 years and >250,000 hectares of xeric conifer forests in northeastern Washington. We found that LiDAR-derived estimates of understory vegetation density were only able to predict field-sampled vegetation biomass when the two sampling methods occurred within 3 years of each other, and overstory canopy cover was <50 percent. Our results demonstrate limitations in the ability of LiDAR, at the intensity and frequency currently applied for multiuse purposes, to measure the quantity of forage. However, further testing with synchronous field sampling and higher-density laser pulses holds promise.

Improving Estimation of Forest Canopy Cover by Introducing Loss Ratio of Laser Pulses Using Airborne LiDAR

2020 ◽  
Vol 58 (1) ◽  
pp. 567-585 ◽  
Author(s):  
Qingwang Liu ◽  
Liyong Fu ◽  
Guangxing Wang ◽  
Shiming Li ◽  
Zengyuan Li ◽  
...  
Keyword(s):  
Forest Canopy ◽  
Canopy Cover ◽  
Laser Pulses ◽  
Airborne Lidar ◽  
Loss Ratio

Quantifying understory vegetation density using small-footprint airborne lidar

2018 ◽  
Vol 215 ◽  
pp. 330-342 ◽  
Author(s):  
Michael J. Campbell ◽  
Philip E. Dennison ◽  
Andrew T. Hudak ◽  
Lucy M. Parham ◽  
Bret W. Butler
Keyword(s):  
Understory Vegetation ◽  
Airborne Lidar ◽  
Vegetation Density ◽  
Small Footprint

scholarly journals Using Airborne Lidar to Discern Age Classes of Cottonwood Trees in a Riparian Area

2006 ◽  
Vol 21 (3) ◽  
pp. 149-158 ◽  
Author(s):  
A. Farid ◽  
D.C. Goodrich ◽  
S. Sorooshian
Keyword(s):  
Canopy Cover ◽  
Laser Pulses ◽  
Airborne Lidar ◽  
Lidar Data ◽  
Linear Regression Models ◽  
Age Classes ◽  
Forest Inventories ◽  
Cottonwood Trees ◽  
Airborne Lidar Data ◽  
Remote Sensing Methods

Abstract Airborne lidar (light detecting and ranging) is a useful tool for probing the structure of forest canopies. Such information is not readily available from other remote sensing methods and is essential for modern forest inventories. In this study, small-footprint lidar data were used to estimate biophysical properties of young, mature, and old cottonwood trees in the San Pedro River basin near Benson, Arizona. The lidar data were acquired in June 2004, using Optech’s 1233 ALTM during flyovers conducted at an altitude of 600 m. Canopy height, crown diameter, stem dbh, canopy cover, and mean intensity of return laser pulses from the canopy surface were estimated for the cottonwood trees from the data. Linear regression models were used to develop equations relating lidar-derived tree characteristics with corresponding field acquired data for each age class of cottonwoods. The lidar estimates show a good degree of correlation with ground-based measurements. This study also shows that other parameters of young, mature, and old cottonwood trees such as height and canopy cover, when derived from lidar, are significantly different (P < 0.05). Additionally, mean crown diameters of mature and young trees are not statistically different at the study site (P = 0.31). The results illustrate the potential of airborne lidar data to differentiate different age classes of cottonwood trees for riparian areas quickly and quantitatively. West. J. Appl. For. 21(3):149–158.

Development of canopy cover and woody vegetation biomass on reclaimed and unreclaimed post-mining sites

2015 ◽  
Vol 84 ◽  
pp. 233-239 ◽  
Author(s):  
Jan Frouz ◽  
Petr Dvorščík ◽  
Alena Vávrová ◽  
Olga Doušová ◽  
Štěpánka Kadochová ◽  
...  
Keyword(s):  
Canopy Cover ◽  
Woody Vegetation ◽  
Mining Sites ◽  
Vegetation Biomass

scholarly journals Processing and analysis of airborne full-waveform laser scanning data for the characterization of forest structure and fuel properties

2020 ◽  
pp. 95
Author(s):  
P. Crespo-Peremarch ◽  
L. A. Ruiz
Keyword(s):  
Forest Structure ◽  
Laser Scanning ◽  
Software Tool ◽  
Understory Vegetation ◽  
Airborne Laser Scanning ◽  
Vegetation Density ◽  
Regression Methods ◽  
Full Waveform ◽  
Airborne Laser ◽  
Pulse Density

<p class="Bodytext">This PhD thesis addresses the development of full-waveform airborne laser scanning (ALS<sub>FW</sub>) processing and analysis methods to characterize the vertical forest structure, in particular the understory vegetation. In this sense, the influence of several factors such as pulse density, voxel parameters (voxel size and assignation value), scan angle at acquisition, radiometric correction and regression methods is analyzed on the extraction of ALS<sub>FW</sub> metric values and on the estimate of forest attributes. Additionally, a new software tool to process ALS<sub>FW</sub> data is presented, which includes new metrics related to understory vegetation. On the other hand, occlusion caused by vegetation in the ALS<sub>FW</sub>, discrete airborne laser scanning (ALS<sub>D</sub>) and terrestrial laser scanning (TLS) signal is characterized along the vertical structure. Finally, understory vegetation density is detected and determined by ALS<sub>FW</sub> data, as well as characterized by using the new proposed metrics.</p>

scholarly journals Estimation of crown and canopy cover from airborne lidar data

2010 ◽  
Vol 52 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Mait Lang
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Stand Structure ◽  
Canopy Cover ◽  
Airborne Lidar ◽  
Silver Birch ◽  
Lidar Data ◽  
Crown Cover ◽  
Pine Trees ◽  
Airborne Lidar Data

Metsa katvuse ja liituse hindamine lennukilt laserskanneriga Tests were carried out in mature Scots pine, Norway spruce and Silver birch stands at Järvselja, Estonia, to estimate canopy cover (K) and crown cover (L) from airborne lidar data. Independent estimates Kc and Lc for K and L were calculated from the Cajanus tube readings made on the ground at 1.3 m height. Lidar data based cover estimates depended on the inclusion of different order returns significantly. In all the stands first order return based estimate K1 was biased positively (3-10%) at the reference height of 1.3 m compared to ground measurements. All lidar based estimates decreased with increasing the reference height. Single return (Ky) and all return (Kk) based canopy cover estimates depended more on the sand structure compared to K1. The ratio of all return count to the first return count D behaved like crown cover estimate in all stands. However, in spruce stand D understimated Lc significantly. In the Scots pine stand K1(1.3) = 0.7431 was most similar canopy cover estimate relative to the ground estimate Kc = 0,7362 whereas Ky(1.3) and Kk(1.3) gave significant underestimates (>15%) of K. Caused by the simple structure of Scots pine stand - only one layer pine trees, the Cajanus tube based canopy cover (Kc), crown cover (Lc) and lidar data based canopy density D(1.3) values were rather similar. In the Norway spruce stand and in the Silver birch stand second layer and regeneration trees were present. In the Silver birch stand Kk(1.3) and Ky(1.3) estimated Kc rather well. In the Norway spruce stand Ky(1.3) and K1(1.3) were the best estimators of Kc whereas Kk(1.3) underestimated canopy cover. Lidar data were found to be usable for canopy cover and crown cover assessment but the selection of the estimator is not trivial and depends on the stand structure.

scholarly journals Canopy cover and anurans: nutrients are the most important predictor of growth and development

2016 ◽  
Vol 94 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Freya E. Rowland ◽  
Sara K. Tuttle ◽  
María J. González ◽  
Michael J. Vanni
Keyword(s):  
Growth And Development ◽  
Large Scale ◽  
Food Resource ◽  
Canopy Cover ◽  
Resource Quality ◽  
Bottom Up ◽  
Growth And Survival ◽  
Primary Producer ◽  
Full Factorial ◽  
Potential Food

Bottom-up effects such as the availability of light and nutrients can have large impacts on primary producer quantity and quality, which is then translated into the growth and development of consumers. The use of “canopy cover” as a bottom-up predictive factor is a broad categorization, as canopy cover controls both the amount of light allowed into a pond and the nutrient load through leaf litter. To test how light and nutrients influence pond ecosystems, we manipulated inorganic nutrients and light in a 2 × 3 full-factorial, large-scale mesocosm experiment. Larval American Bullfrogs (Lithobates catesbeianus (Shaw, 1802)) were reared for 6 weeks at low densities and then assessed for development, growth, and survival at the end of the experiment. We also collected weekly samples of potential food resources (phytoplankton and periphyton) for the estimation of algal production and stoichiometric quality (carbon:nitrogen:phosphorus). Light had strong effects on food resource quality; however, resource quality did not significantly predict tadpole growth or development. Instead, nutrients seemed to be the most important factor as a stimulator of total algal primary production and some unknown pathway, which in turn affected tadpole development. Ours is the first study to investigate canopy cover using a comprehensive causal model, and our results suggest in regards to tadpole growth and development, canopy cover is important mainly as a source of nutrients to ponds.

The Use of the Land Survey Record to Assess Changes in Vegetation Structure. A Case Study From the Darling Downs, Queensland, Australia.

1998 ◽  
Vol 20 (1) ◽  
pp. 132 ◽  
Author(s):  
RJ Fensham ◽  
JE Holman
Keyword(s):  
Vegetation Structure ◽  
Canopy Cover ◽  
Vegetation Density ◽  
Crown Cover ◽  
Standard Application ◽  
Land Survey ◽  
Minor Vegetation ◽  
Structural Category ◽  
Historical Photographs

Fifteen references to vegetation structure from the historical land survey record for the eastern Darling Downs were calibrated with historical photographs to determine the use of the surveyors' structural terminology (Open: 'open', 'light': Dense: 'heavy', 'thick', 'dense'). Sites with less than 40% canopy cover were only described by terms included within the Open category, and sites with greater than 50% canopy cover were only described by terms included within the Dense category. These results provide calibrations of the surveyors' structural terminology indicating terms were unambiguously applied outside the 40-50% canopy cover range. The use of corner tree distances as an absolute measure of vegetation density is warned against because corner trees had to meet certain criteria and were not necessarily the nearest tree to any corner. However, the distance from allotment corners to "corner trees" provided a measure of the relative use of the surveyor's structural epithets and is consistent with standard application among their fraternity. Survey records dating from 1864-1910 were compared with the structure of existing remnants (projective crown cover measured from recent 1:25,000 aerial photography) to assess changes in vegetation structure. The analysis suggests that 88% of the 34 sites included in the analysis have not changed from the broad structural category that was assigned by the surveyors. Using the assumptions developed by this study, two sites were assessed as having thickened substantially. These results suggest that only minor vegetation thickening has occurred in the Darling Downs since the early land surveys. This conclusion is supported by direct comparison of the historical photographs with existing remnants. indicating that only one site out of 17 has thickened substantially.

scholarly journals Overstory–Understory Vegetation Cover and Soil Water Content Observations in Western Juniper Woodlands: A Paired Watershed Study in Central Oregon, USA

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 151 ◽  
Author(s):  
Grace Ray ◽  
Carlos G. Ochoa ◽  
Tim Deboodt ◽  
Ricardo Mata-Gonzalez
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Canopy Cover ◽  
Understory Vegetation ◽  
Watershed Scale ◽  
Shrub Cover ◽  
Western Juniper ◽  
Tree Canopy Cover

The effects of western juniper (Juniperus occidentalis) control on understory vegetation and soil water content were studied at the watershed-scale. Seasonal differences in topsoil (12 cm) water content, as affected by vegetation structure and soil texture, were evaluated in a 96-ha untreated watershed and in a 116-ha watershed where 90% juniper was removed in 2005. A watershed-scale characterization of vegetation canopy cover and soil texture was completed to determine some of the potential driving factors influencing topsoil water content fluctuations throughout dry and wet seasons for approximately one year (2014–2015). We found greater perennial grass, annual grass, and shrub cover in the treated watershed. Forb cover was no different between watersheds, and as expected, tree canopy cover was greater in the untreated watershed. Results also show that on average, topsoil water content was 1% to 3% greater in the treated watershed. The exception was during one of the wettest months (March) evaluated, when soil water content in the untreated watershed exceeded that of the treated by <2%. It was noted that soil water content levels that accumulated in areas near valley bottoms and streams were greater in the treated watershed than in the untreated toward the end of the study in late spring. This is consistent with results obtained from a more recent study where we documented an increase in subsurface flow residence time in the treated watershed. Overall, even though average soil water content differences between watersheds were not starkly different, the fact that more herbaceous vegetation and shrub cover were found in the treated watershed led us to conclude that the long-term effects of juniper removal on soil water content redistribution throughout the landscape may be beneficial towards restoring important ecohydrologic connections in these semiarid ecosystems of central Oregon.

scholarly journals How Surface Radiation on Forested Snowpack Changes across a Latitudinal Gradient

Hydrology ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 62 ◽  
Author(s):  
Bijan Seyednasrollah ◽  
Mukesh Kumar
Keyword(s):  
Picea Glauca ◽  
Forest Floor ◽  
Latitudinal Gradient ◽  
Geographical Location ◽  
Canopy Cover ◽  
Surface Radiation ◽  
Net Radiation ◽  
Vegetation Density ◽  
Clear Sky ◽  
Sky Conditions

Radiation is the major driver of snowmelt, and, hence, its estimation is critically important. Net radiation reaching the forest floor is influenced by vegetation density. Previous studies in mid-latitude conifer forests have confirmed that net radiation decreases and then subsequently increases with increasing vegetation density, for clear sky conditions. This leads to the existence of a net radiation minimum at an intermediate vegetation density. With increasing cloud cover, the minimum radiation shifts toward lower densities, sometimes resulting in a monotonically increasing radiation with vegetation density. The net radiation trend, however, is expected to change across sites, affecting the magnitude and timing of individual radiation components. This research explores the variability of net radiation on a snow-covered forest floor for different vegetation densities along a latitudinal gradient. We especially investigate how the magnitude of minimum/maximum radiation and the corresponding vegetation density change with the site geographical location. To evaluate these, the net radiation is evaluated using the Forest Radiation Model at six different locations in predominantly white spruce (Picea glauca) canopy cover across North America, ranging from 45 to 66° N latitudes. Results show that the variation of net radiation with vegetation density considerably varies with latitude. In higher latitude forests, the magnitude of net radiation is generally smaller, and the minimum radiation is exhibited at relatively sparser vegetation densities, under clear sky conditions. For interspersed cloudy sky conditions, net radiation non-monotonically varies with latitude across the sites, depending on the seasonal sky cloudiness and air temperature. The latitudinal sensitivity of net radiation is lower on north-facing hillslopes than on south-facing sites.

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