Journal articles on the topic 'Canopy cover'
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Aalto, Iris Johanna, Eduardo Eiji Maeda, Janne Heiskanen, Eljas Kullervo Aalto, and Petri Kauko Emil Pellikka. "Strong influence of trees outside forest in regulating microclimate of intensively modified Afromontane landscapes." Biogeosciences 19, no. 17 (September 8, 2022): 4227–47. http://dx.doi.org/10.5194/bg-19-4227-2022.
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Abstract. Climate change is expected to have detrimental consequences on fragile ecosystems, threatening biodiversity, as well as food security of millions of people. Trees are likely to play a central role in mitigating these impacts. The microclimatic conditions below tree canopies usually differ substantially from the ambient macroclimate as vegetation can buffer temperature changes and variability. Trees cool down their surroundings through several biophysical mechanisms, and the cooling benefits occur also with trees outside forest. The aim of this study was to examine the effect of canopy cover on microclimate in an intensively modified Afromontane landscape in Taita Taveta, Kenya. We studied temperatures recorded by 19 microclimate sensors under different canopy covers, as well as land surface temperature (LST) estimated by Landsat 8 thermal infrared sensor. We combined the temperature records with high-resolution airborne laser scanning data to untangle the combined effects of topography and canopy cover on microclimate. We developed four multivariate regression models to study the joint impacts of topography and canopy cover on LST. The results showed a negative linear relationship between canopy cover percentage and daytime mean (R2=0.65) and maximum (R2=0.75) temperatures. Any increase in canopy cover contributed to reducing temperatures. The average difference between 0 % and 100 % canopy cover sites was 5.2 ∘C in mean temperatures and 10.2 ∘C in maximum temperatures. Canopy cover (CC) reduced LST on average by 0.05 ∘C per percent CC. The influence of canopy cover on microclimate was shown to vary strongly with elevation and ambient temperatures. These results demonstrate that trees have a substantial effect on microclimate, but the effect is dependent on macroclimate, highlighting the importance of maintaining tree cover particularly in warmer conditions. Hence, we demonstrate that trees outside forests can increase climate change resilience in fragmented landscapes, having strong potential for regulating regional and local temperatures.
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Hilton Wolschick, Neuro, Fabrício Tondello Barbosa, Ildegardis Bertol, Kristiana Fiorentin dos Santos, Romeu de Souza Werner, and Bárbara Bagio. "Cobertura do solo, produção de biomassa e acúmulo de nutrientes por plantas de cobertura." Revista de Ciências Agroveterinárias 15, no. 2 (August 15, 2016): 134–43. http://dx.doi.org/10.5965/223811711522016134.
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Ashapure, Akash, Jinha Jung, Anjin Chang, Sungchan Oh, Murilo Maeda, and Juan Landivar. "A Comparative Study of RGB and Multispectral Sensor-Based Cotton Canopy Cover Modelling Using Multi-Temporal UAS Data." Remote Sensing 11, no. 23 (November 23, 2019): 2757. http://dx.doi.org/10.3390/rs11232757.
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This study presents a comparative study of multispectral and RGB (red, green, and blue) sensor-based cotton canopy cover modelling using multi-temporal unmanned aircraft systems (UAS) imagery. Additionally, a canopy cover model using an RGB sensor is proposed that combines an RGB-based vegetation index with morphological closing. The field experiment was established in 2017 and 2018, where the whole study area was divided into approximately 1 x 1 m size grids. Grid-wise percentage canopy cover was computed using both RGB and multispectral sensors over multiple flights during the growing season of the cotton crop. Initially, the normalized difference vegetation index (NDVI)-based canopy cover was estimated, and this was used as a reference for the comparison with RGB-based canopy cover estimations. To test the maximum achievable performance of RGB-based canopy cover estimation, a pixel-wise classification method was implemented. Later, four RGB-based canopy cover estimation methods were implemented using RGB images, namely Canopeo, the excessive greenness index, the modified red green vegetation index and the red green blue vegetation index. The performance of RGB-based canopy cover estimation was evaluated using NDVI-based canopy cover estimation. The multispectral sensor-based canopy cover model was considered to be a more stable and accurately estimating canopy cover model, whereas the RGB-based canopy cover model was very unstable and failed to identify canopy when cotton leaves changed color after canopy maturation. The application of a morphological closing operation after the thresholding significantly improved the RGB-based canopy cover modeling. The red green blue vegetation index turned out to be the most efficient vegetation index to extract canopy cover with very low average root mean square error (2.94% for the 2017 dataset and 2.82% for the 2018 dataset), with respect to multispectral sensor-based canopy cover estimation. The proposed canopy cover model provides an affordable alternate of the multispectral sensors which are more sensitive and expensive.
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Huffman, Ronald D., Mary Ann Fajvan, and Petra Bohall Wood. "Effects of residual overstory on aspen development in Minnesota." Canadian Journal of Forest Research 29, no. 2 (February 1, 1999): 284–89. http://dx.doi.org/10.1139/x98-202.
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The effects of different amounts of residual canopy on stand development of quaking aspen (Populus tremuloides Michx.) were examined in a chronosequence of 32 stands spanning 6-10 years since harvest. Residual canopy covers ranged from 0 to 65%, and residual basal areas ranged from 0 to 14.4 m2/ha. Aspen regeneration densities ranged from 7130 to 43 672 stems/ha. Regeneration stem density was affected primarily by residual canopy cover (R2 = 0.27, P = 0.0001) and secondarily by stand age (R2 = 0.09, P = 0.004). Aspen density decreased significantly with increasing residual canopy cover for 7-year-old and 8-year-old regeneration. Residual canopy cover did not significantly affect aspen density in 9-year-old regeneration (R2 = 0.02, P = 0.579) but was negatively related to total height of 9-year-old codominant aspens (R2 = 0.49, P = 0.002). Canopy cover was a more accurate representation of the amount of shade the regeneration received than the density or basal area of residual trees. However, the low value of the coefficient of determination from a multiple-regression model indicates that considerable variation in stem densities and height was unexplained by residual canopy cover, even though it was the best predictor of the variables measured.
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Arya*, Neeta, and Jeet Ram. "Influence of canopy cover on vegetation in P. roxburghii sarg (chir-pine) dominated forests in Uttarakhand Himalaya, India." International Journal of Bioassays 5, no. 06 (May 31, 2016): 4617. http://dx.doi.org/10.21746/ijbio.2016.06.006.
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Increasing anthropogenic pressure and dependence on plant products have led to widespread exploitation of natural forests in the Uttaranchal Himalaya. The present study was carried out to study the influence of canopy cover on tree, shrub and herb vegetation. For this three different canopy types, open canopy (<30%, cover), moderate canopy (30-60%, cover) and close canopy (>60%, cover) were identified in Pinus roxburghii (chir-pine) dominated forests. The study area is located between 290 20’and 290 30’ N latitude and 790 23’ and 790 42’ E longitude between 1350-2000m elevations in Uttarakhand a newly created hill state. Total tree density was high in close canopy sites basal area was greater in open canopy sites. Total shrub density varied from 26107 to 28560 shrub/ha. It was maximum for open canopy sites and minimum for moderate canopy sites. Total shrubs cover varied from 45.8 to 50.6%. Shrubs cover was maximum for moderate canopy sites and minimum for open canopy sites. Herbs density was greater in open canopy and total herbs cover was greater in close canopy. Tree and shrub diversity was high in close canopy sites and herbs diversity in open canopy sites.
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Aditya, Rendy Bayu, and Muhammad Ulul Lizamun Ningam. "Assessing City Greenness using Tree Canopy Cover: The Case of Yogyakarta, Indonesia." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 14, no. 1 (April 5, 2021): 71–80. http://dx.doi.org/10.24057/10.24057/2071-9388-2020-196.
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The study aims to measure the greenness of an Indonesia city using tree canopy cover data. Rapid physical development brings impacts to the loss of urban trees, which leads to the increase of flooding risk, local temperature and pollution level. To address the issues, a baseline assessment of urban tree canopy existence is necessary as inputs for effective urban environmental management policies. The methods used in this research include 1) remote sensing and spatial analysis, and 2) simple quantitative analysis. Furthermore, three indicators are used in assessing the greenness, including 1) size of the canopy, 2) canopy cover percentage, and 3) canopy per capita. The results found that the city of Yogyakarta has a low level of greenness based on the canopy size in which covers only 467.37 ha or 14.38% of the total area. The second finding is Yogyakarta has an unequal distribution of canopy cover percentage in each district (kecamatan). The third finding is Yogyakarta City has a canopy per capita rate of 10.93 sq m/person. This number is below the UN recommendation of 15sq m / person. It indicates that residents have poor access to urban greenery. Additionally, the article discusses that the three indicators used have strength and weakness in measuring the level of greenness. Therefore, the assessment objectives must be taken into account. We recommend the use of each indicator as follows: 1) the canopy size is used as an initial inventory of the existence and distribution of the canopy, 2) the canopy cover percentage canopy percentage for measuring and comparing the level of greenness spatially and visually between areas, 3) the canopy per capita is used to measure the possibility of access and interaction of residents with the presence of a tree canopy. Cities’ authority can use the information to measure the achievement of SDGs number 11, 13, or 15.
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Aditya, Rendy Bayu, and Muhammad Ulul Lizamun Ningam. "Assessing City Greenness using Tree Canopy Cover: The Case of Yogyakarta, Indonesia." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 14, no. 1 (April 5, 2021): 71–80. http://dx.doi.org/10.24057/2071-9388-2020-212.
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The study aims to measure the greenness of an Indonesia city using tree canopy cover data. Rapid physical development brings impacts to the loss of urban trees, which leads to the increase of flooding risk, local temperature and pollution level. To address the issues, a baseline assessment of urban tree canopy existence is necessary as inputs for effective urban environmental management policies. The methods used in this research include 1) remote sensing and spatial analysis, and 2) simple quantitative analysis. Furthermore, three indicators are used in assessing the greenness, including 1) size of the canopy, 2) canopy cover percentage, and 3) canopy per capita. The results found that the city of Yogyakarta has a low level of greenness based on the canopy size in which covers only 467.37 ha or 14.38% of the total area. The second finding is Yogyakarta has an unequal distribution of canopy cover percentage in each district (kecamatan). The third finding is Yogyakarta City has a canopy per capita rate of 10.93 sq m/person. This number is below the UN recommendation of 15sq m / person. It indicates that residents have poor access to urban greenery. Additionally, the article discusses that the three indicators used have strength and weakness in measuring the level of greenness. Therefore, the assessment objectives must be taken into account. We recommend the use of each indicator as follows: 1) the canopy size is used as an initial inventory of the existence and distribution of the canopy, 2) the canopy cover percentage canopy percentage for measuring and comparing the level of greenness spatially and visually between areas, 3) the canopy per capita is used to measure the possibility of access and interaction of residents with the presence of a tree canopy. Cities’ authority can use the information to measure the achievement of SDGs number 11, 13, or 15.
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Aditya, Rendy Bayu, and Muhammad Ulul Lizamun Ningam. "Assessing City Greenness using Tree Canopy Cover: The Case of Yogyakarta, Indonesia." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 14, no. 1 (April 5, 2021): 71–80. http://dx.doi.org/10.24057/2071-9388-2020-196.
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The study aims to measure the greenness of an Indonesia city using tree canopy cover data. Rapid physical development brings impacts to the loss of urban trees, which leads to the increase of flooding risk, local temperature and pollution level. To address the issues, a baseline assessment of urban tree canopy existence is necessary as inputs for effective urban environmental management policies. The methods used in this research include 1) remote sensing and spatial analysis, and 2) simple quantitative analysis. Furthermore, three indicators are used in assessing the greenness, including 1) size of the canopy, 2) canopy cover percentage, and 3) canopy per capita. The results found that the city of Yogyakarta has a low level of greenness based on the canopy size in which covers only 467.37 ha or 14.38% of the total area. The second finding is Yogyakarta has an unequal distribution of canopy cover percentage in each district (kecamatan). The third finding is Yogyakarta City has a canopy per capita rate of 10.93 sq m/person. This number is below the UN recommendation of 15sq m / person. It indicates that residents have poor access to urban greenery. Additionally, the article discusses that the three indicators used have strength and weakness in measuring the level of greenness. Therefore, the assessment objectives must be taken into account. We recommend the use of each indicator as follows: 1) the canopy size is used as an initial inventory of the existence and distribution of the canopy, 2) the canopy cover percentage canopy percentage for measuring and comparing the level of greenness spatially and visually between areas, 3) the canopy per capita is used to measure the possibility of access and interaction of residents with the presence of a tree canopy. Cities’ authority can use the information to measure the achievement of SDGs number 11, 13, or 15.
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Nur Syahida, A. M., and A. B. Azinoor Azida. "The effect of vegetation canopy on canopy storage capacity with different rainfall intensity." MATEC Web of Conferences 250 (2018): 04001. http://dx.doi.org/10.1051/matecconf/201825004001.
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Canopy Interception is one of the vital component in hydrological cycle and underestimating the interception process can significantly affect the water balance. A study of rainfall interception was conducted using rainfall simulator called hydrology apparatus. Three different rainfall intensities were used in this study; 90 mm/hr, 140 mm/hr and 180 mm/hr. These intensities were produced by 8 nozzles. The test were first carried out on the barren land without the existence of canopy cover. To study the effect of canopy cover on canopy storage capacity, broadleaf plant (Scindapsus Aureus) was used to cover the barren land. The differences between the amount of water discharge between these two different land covers were observed to determine the quantity of water stored in the canopy. Results indicated that Scindapsus Aureus intercepted more water at lower intensity than at higher intensity. The lowest intensity was 90 mm/hr stored 1.6mm of rainwater while 140 mm/hr retained 0.8 mm. 180 mm/hr was the highest rainfall intensity used in this study intercepted 0.3mm of total precipitation. Therefore, this study proved that rainfall intensity is one of the main factors that influence the rainfall interception process.
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Fidelibus, Matthew W., Stephen J. Vasquez, and S. Kaan Kurtural. "Late-season Plastic Canopy Covers Affect Canopy Microclimate and Fruit Quality of ‘Autumn King’ and ‘Redglobe’ Table Grapes." HortTechnology 26, no. 2 (April 2016): 141–47. http://dx.doi.org/10.21273/horttech.26.2.141.
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California table grape (Vitis vinifera) growers cover the canopies of late-season varieties with plastic (polyethylene) covers to shield the fruit from rain. Green- or white-colored covers are commonly used, but there is lack of information whether either cover might be preferable based on canopy microclimate or fruit quality. In late September, ‘Redglobe’ (in 2011) and ‘Autumn King’ (in 2012) table grapevines were covered with green or white plastic, or left uncovered, and canopy microclimate, fungal and bacterial rot incidence, and fruit yield and quality at harvest, and after postharvest storage, were evaluated. Green covers were more transparent and less reflective than white covers, and daily maximum temperature difference in the top center of the canopies of grapevine with green covers was consistently >5 °C than that of grapevine subjected to other treatments, but covers had little effect on temperatures in the fruit zones, which were not enveloped by covers. Effects on relative humidity (RH) depended on location within the canopy and time of day; RH peaked in early morning and was at a minimum in late afternoon. All cover treatments had relatively similar peak RH in south-facing fruit zones and the top center of the canopy. However, in the north-facing fruit zone, vines with green covers had higher RH at night than vines subjected to other treatments. Both covers consistently reduced evaporative potential in the top center of the canopy, but not in fruit zones. Treatment effects on condensation beneath the covers were inconsistent, possibly due to differences in canopy size, variety, or season, but south-facing cover surfaces generally had less condensation than the top or north-facing surfaces. About 0.5 inch of rain fell on 5 Oct. 2011, but no rain occurred during the 2012 experiment. In 2011, green covers delayed fruit maturation slightly, but not in 2012. Covers did not affect vineyard rot incidence, the number of boxes of fruit harvested, or postharvest fruit quality in 2011, but fruit from covered grapevine had less postharvest rot in 2012 than fruit from noncovered grapevines, even though a measurable rain event occurred in 2011 but not in 2012. In conclusion, our results suggest that white covers may be preferable to green since green covers were associated with higher temperatures in both seasons and higher RH in the ‘Autumn King’ trial of 2012, but otherwise performed similarly.
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Hannah, Peter R. "Regeneration of Northern Hardwoods in the Northeast with the Shelterwood Method." Northern Journal of Applied Forestry 8, no. 3 (September 1, 1991): 99–104. http://dx.doi.org/10.1093/njaf/8.3.99.
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Abstract Study plots (1/4 ac) were located in four northern hardwood stands in Vermont, and shelterwood canopy covers of 40, 60, 80, and 100%, and a control (no cutting) were established. Regeneration on small plots within the treated areas was sampled over a 3-year period and the composition of saplings determined after 6 years. While there were substantial increases in amount of regeneration under most canopy covers, there was no significant differences due to treatment. Some important trends, however, were evident. Sugar maple showed some increase in seedling density under most canopy densities with up to 68,000 new sugar maple seedlings per acre under 60% canopy cover. Yellow birch did best under 40 to 80% canopy cover and with good soil scarification. White ash increased under most densities but was best at about 80% canopy cover. Competitors, beech, striped maple, and hobblebush, increased under most densities. At about 60% canopy cover and less, raspberries and blackberries, pin cherry, and other shade-intolerant species increase in abundance. Among regeneration less than 3 ft all after 3 years, preferred species outnumbered less preferred species by 5 to 1. Among regeneration over 3 ft tall when examined 6 years after treatment, the less preferred species, on average, outnumber preferred species by 2 to 1 (sugar maple 0-3430/ac, yellow birch 0-1920/ac, beech 200-2220/ac and striped maple 0-3130/ac). Most beech regeneration seemed to arise as root suckers. Small striped maple grew rapidly and assumed dominance among the regeneration when released. Northern hardwoods have diverse composition in the overstory, and much of the regeneration tallied after 3 years was already in place when the shelterwood cuts were made. Advanced regeneration as well as new regeneration is the key to success, or failure, if it is predominantly undesirable species. In implementing a shelterwood in northern hardwoods, 60 to 80% canopy cover seems good for most species. All trees below the main canopy should be cut to create a high canopy shade. Undesirable species should be controlled by cutting or possibly herbicides before or when the stand is cut, with additional treatment as necessary to maintain desired composition. North. J. Appl. For. 8(3):99-104.
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Hamilton, Dale A., Kamden L. Brothers, Samuel D. Jones, Jason Colwell, and Jacob Winters. "Wildland Fire Tree Mortality Mapping from Hyperspatial Imagery Using Machine Learning." Remote Sensing 13, no. 2 (January 15, 2021): 290. http://dx.doi.org/10.3390/rs13020290.
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The use of imagery from small unmanned aircraft systems (sUAS) has enabled the production of more accurate data about the effects of wildland fire, enabling land managers to make more informed decisions. The ability to detect trees in hyperspatial imagery enables the calculation of canopy cover. A comparison of hyperspatial post-fire canopy cover and pre-fire canopy cover from sources such as the LANDFIRE project enables the calculation of tree mortality, which is a major indicator of burn severity. A mask region-based convolutional neural network was trained to classify trees as groups of pixels from a hyperspatial orthomosaic acquired with a small unmanned aircraft system. The tree classification is summarized at 30 m, resulting in a canopy cover raster. A post-fire canopy cover is then compared to LANDFIRE canopy cover preceding the fire, calculating how much the canopy was reduced due to the fire. Canopy reduction allows the mapping of burn severity while also identifying where surface, passive crown, and active crown fire occurred within the burn perimeter. Canopy cover mapped through this effort was lower than the LANDFIRE Canopy Cover product, which literature indicated is typically over reported. Assessment of canopy reduction mapping on a wildland fire reflects observations made both from ground truthing efforts as well as observations made of the associated hyperspatial sUAS orthomosaic.
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Coulston, John W., Gretchen G. Moisen, Barry T. Wilson, Mark V. Finco, Warren B. Cohen, and C. Kenneth Brewer. "Modeling Percent Tree Canopy Cover." Photogrammetric Engineering & Remote Sensing 78, no. 7 (July 1, 2012): 715–27. http://dx.doi.org/10.14358/pers.78.7.715.
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Zimba, Henry, Miriam Coenders-Gerrits, Banda Kawawa, Hubert Savenije, Imasiku Nyambe, and Hessel Winsemius. "Variations in Canopy Cover and Its Relationship with Canopy Water and Temperature in the Miombo Woodland Based on Satellite Data." Hydrology 7, no. 3 (August 16, 2020): 58. http://dx.doi.org/10.3390/hydrology7030058.
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Understanding the canopy cover relationship with canopy water content and canopy temperature in the Miombo ecosystem is important for studying the consequences of climate change. To better understand these relationships, we studied the satellite data-based land surface temperature (LST) as proxy for canopy temperature, leaf area index (LAI), and the normalized difference vegetation index (NDVI) as proxies for canopy cover. Meanwhile, the normalized difference infrared index (NDII) was used as a proxy for canopy water content. We used several statistical approaches including the correlated component regression linear model (CCR.LM) to understand the relationships. Our results showed that the most determinant factor of variations in the canopy cover was the interaction between canopy water content (i.e., NDII) and canopy temperature (i.e., LST) with coefficients of determination (R2) ranging between 0.67 and 0.96. However, the coefficients of estimates showed the canopy water content (i.e., NDII) to have had the largest percentage of the interactive effect on the variations in canopy cover regardless of the proxy used i.e., LAI or NDVI. From 2009–2018, the NDII (proxy for canopy water content) showed no significant (at alpha level 0.05) trend. However, there was a significant upward trend in LST (proxy for canopy temperature) with a magnitude of 0.17 °C/year. Yet, the upward trend in LST did not result in significant (at alpha level 0.05) downward changes in canopy cover (i.e., proxied by LAI and NDVI). This result augments the observed least determinant factor characterization of temperature (i.e., LST) on the variations in canopy cover as compared to the vegetation water content (i.e., NDII).
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Bailey, Amanda M., Holly K. Ober, Brian E. Reichert, and Robert A. McCleery. "Canopy Cover Shapes Bat Diversity across an Urban and Agricultural Landscape Mosaic." Environmental Conservation 46, no. 03 (June 13, 2019): 193–200. http://dx.doi.org/10.1017/s0376892919000109.
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SummaryHuman alteration of the planet’s terrestrial landscapes for agriculture, habitation and commerce is reshaping wildlife communities. The threat of land cover change to wildlife is pronounced in regions with rapidly growing human populations. We investigated how species richness and species-specific occurrence of bats changed as a function of land cover and canopy (tree) cover across a rapidly changing region of Florida, USA. Contrary to our predictions, we found negligible effects of agriculture and urban development on the occurrence of all species. In contrast, we found that a remotely sensed metric of canopy cover on a broad scale (25 km2) was a good predictor of the occurrence of eight out of ten species. The occurrence of all smaller bats (vespertilionids) in our study increased with 0–50% increases in canopy cover, while larger bats showed different patterns. Occurrence of Brazilian free-tailed bats (Tadarida brasiliensis) decreased with increasing canopy cover, and Florida bonneted bats (Eumops floridanus) were not influenced by canopy cover. We conclude that remotely sensed measures of canopy cover can provide a more reliable predictor of bat species richness than land-cover types, and efforts to prevent the loss of bat diversity should consider maintaining canopy cover across mosaic landscapes with diverse land-cover types.
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Bravo-Bello, Juan C., Tomas Martinez-Trinidad, J. Rene Valdez-Lazalde, Martin E. Romero-Sanchez, and Sergio Martinez-Trinidad. "Analyzing Potential Tree-Planting Sites and Tree Coverage in Mexico City Using Satellite Imagery." Forests 11, no. 4 (April 9, 2020): 423. http://dx.doi.org/10.3390/f11040423.
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Locating potential tree-planting sites and analyzing tree canopy cover is important in the planning and management of urban forests. This paper reports the quantification of potential planting sites as well as tree canopy cover in the urban area of Mexico City, estimated by means of SPOT (Satellite Pour l’Observation de la Terre) 6 satellite images and a supervised pixel-based classification approach. Results showed an estimated area of 3100.7 ha of potentially useful sites, including places with bare soil and grass-covered areas such as median strips, roundabouts and parks. An average tree canopy cover of 10.6% and an average impervious surface of 79.2% for the 15 boroughs were also analyzed. The area of potential planting sites would represent a 5% gain for the current tree canopy cover if it were to be planted. With an overall accuracy of 92.4%, the use of both images from the SPOT 6 sensor and the classification approach proved to be appropriate for obtaining thematic covers in the urban environment of Mexico City.
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Anderson, Benjamin D., Gary W. Knox, Ann R. Blount, Cheryl L. Mackowiak, and Edward F. Gilman. "Ornamental Groundcover Characteristics of Rhizoma Peanut (Arachis glabrata Benth.): Shade Affects Height but not Cover." HortScience 50, no. 7 (July 2015): 952–56. http://dx.doi.org/10.21273/hortsci.50.7.952.
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Rhizoma peanut has the potential for use as an ecologically friendly groundcover or turf alternative. Little is known about height and cover characteristics of this plant, which are important ornamental considerations. The objectives of this field study were to characterize maximum average canopy height, height variability, the time to reach full canopy cover, and the time at full canopy cover of seven released and nine experimental selections of rhizoma peanut grown in full sun or under 30% shade at two North Florida locations. Greater height and a less uniform canopy were observed for shaded plants. Establishment, as measured by full canopy cover, did not occur until the second year after planting. Shade treatment had little effect on the time to reach full canopy cover or the duration of full canopy cover, indicating that rhizoma peanut will perform equally in full sun or under 30% shade. Recommended selections for ornamental use based on these variables include ‘Brooksville 67’, ‘Brooksville 68’, EX3, and EX8.
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Paletto, Alessandro, and Vittorio Tosi. "Forest canopy cover and canopy closure: comparison of assessment techniques." European Journal of Forest Research 128, no. 3 (February 21, 2009): 265–72. http://dx.doi.org/10.1007/s10342-009-0262-x.
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Sulistiyono, N., R. Syafitri, and S. A. Hudjimartsu. "Application of sentinel 2A sattelite imagery for the estimation of canopy cover spatial distribution at mangrove vegetation." IOP Conference Series: Earth and Environmental Science 977, no. 1 (June 1, 2022): 012092. http://dx.doi.org/10.1088/1755-1315/977/1/012092.
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Abstract Mangrove canopy density is one of the important variables for monitoring the health of mangrove vegetation. The vegetation index in satellite imagery is one of the variables that can be used to estimate the distribution of mangrove forest canopy cover. This study aims to predict the distribution of canopy cover of mangrove planted in Lubuk Kertang. The method used is regression analysis by connecting the NDVI value in the Sentinel 2A satellite image with the canopy density value in the field. Measurement of canopy cover in the field using a fisheye camera. The use of GIS is used to determine the spatial distribution of canopy cover. This study indicates that the linear regression model can estimate the canopy density distribution of mangrove vegetation in Lubuk Kertang with an R square value of 53.6% (sig < 0.005).
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Walton, Jeffrey, David Nowak, and Eric Greenfield. "Assessing Urban Forest Canopy Cover Using Airborne or Satellite Imagery." Arboriculture & Urban Forestry 34, no. 6 (November 1, 2008): 334–40. http://dx.doi.org/10.48044/jauf.2008.046.
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With the availability of many sources of imagery and various digital classification techniques, assessing urban forest canopy cover is readily accessible to most urban forest managers. Understanding the capability and limitations of various types of imagery and classification methods is essential to interpreting canopy cover values. An overview of several remote sensing techniques used to assess urban forest canopy cover is presented. A case study comparing canopy cover percentages for Syracuse, New York, U.S. interprets the multiple values developed using different methods. Most methods produce relatively similar results, but the estimate based on the National Land Cover Database is much lower.
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Chojnacky, David, Emily Smith-McKenna, Laura Johnson, John McGee, and Cindy Chojnacky. "Evaluating Urban Canopy Cover Before and After Housing Redevelopment in Falls Church, Virginia, USA." Arboriculture & Urban Forestry 46, no. 1 (January 1, 2020): 12–26. http://dx.doi.org/10.48044/jauf.2020.002.
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Local governments have created regulations aimed to maintain and increase valuable urban tree cover. The City of Falls Church, Virginia, USA, requires each residential redevelopment to retain or plant enough trees for 20% canopy cover within ten years. To assess whether this goal is being met, we studied 21 Falls Church residential lots redeveloped between 1994 and 2011 where existing houses had been replaced with larger ones. Initial tree inventories and measurements prior to redevelopment were recorded in redevelopment plans. We remeasured preserved and planted trees in a ground survey and modeled tree canopy growth from a periodic tree diameter growth model linked to a model relating tree and crown diameters. Geospatial analysis was used to calculate nonoverlapping canopy cover within lots from crown diameter measurements and/or model predictions. We found that the City of Falls Church generally met its 20% canopy cover goal, but that the canopy cover metric alone is insufficient to fully describe urban forest recovery. Although canopy cover might recover rapidly from planting many small trees, recovery to the larger tree sizes that maximize ecosystem services can take much longer. Our modeling of lot-scale growth from field measurements showed the potential to manage forests using traditional diameter-based forest metrics that would relate results to canopy cover when needed. These forest stand metrics—based on basal area and trees per hectare—can account for tree size changes masked by the canopy cover metric.
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Christopher, Treg A., and John M. Goodburn. "The Effects of Spatial Patterns on the Accuracy of Forest Vegetation Simulator (FVS) Estimates of Forest Canopy Cover." Western Journal of Applied Forestry 23, no. 1 (January 1, 2008): 5–11. http://dx.doi.org/10.1093/wjaf/23.1.5.
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Abstract The Forest Vegetation Simulator (FVS) estimates percent canopy cover without spatially explicit information. Estimates of canopy cover in FVS can be corrected for crown overlap, based on the assumption that trees in a stand are randomly distributed. This research assessed the accuracy of FVS estimates of canopy cover in stands with nonrandom spatial patterns. A method for measuring canopy cover within a geographic information system was developed to compare with FVS estimates of cover for 19, stem-mapped plots across Idaho and Montana. The Ripley's K(d) statistic was used to describe natural and simulated spatial patterns, so that the accuracy of canopy cover estimated by FVS could be considered for groups of plots classified as regular, clustered, or random. Results from the analyses of the effects of spatial patterns indicated that the FVS may underestimate canopy cover by 11% for plots with highly regular spatial patterns and overestimate by 2% for plots with clustered patterns. Although the magnitude of this bias likely is insufficient to justify changing the model's algorithm for canopy cover, users of this model should be aware of the potential bias that can occur as a result of assuming that trees in a stand are randomly distributed. Information on the general spatial pattern of the stand (i.e., clumped, random, and even) could be used by managers to anticipate the expected degree and direction of the bias.
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Schwab, Francis E., and Michael D. Pitt. "Moose selection of canopy cover types related to operative temperature, forage, and snow depth." Canadian Journal of Zoology 69, no. 12 (December 1, 1991): 3071–77. http://dx.doi.org/10.1139/z91-431.
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Simple linear and muliple regressions were used to determine the contribution of operative temperature (Te), forage, and snow depth to moose (Alces alces) selection of canopy cover types. The number of degree-hours for which Te exceeded the thermal limit at which panting is required to dissipate metabolic heat contributed significantly to selection during summer (1 June – 15 September) and late winter (16 January – 15 April). Forage explained canopy cover selection in early winter (16 November – 15 January) and contributed significantly to the best equation describing habitat selection during late winter. Snow depth contributed to habitat selection in early winter but was not related to habitat selection during late winter. During summer, moose generally selected against sites where Te exceeded 30 °C, the thermal limit requiring panting to dissipate metabolic heat. During late winter, moose also generally avoided canopy covers where Te commonly exceeded 8 °C, the temperature at which panting is required to dissipate heat. During early winter, moose apparently suffered minimal heat stress, as Te remained below 0 °C; consequently, moose selected canopy cover types that provided comparatively high forage availability.
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Saleh, M. B., R. W. Dewi, L. B. Prasetyo, and N. A. Santi. "Canopy Cover Estimation in Lowland Forest in South Sumatera, Using LiDAR and Landsat 8 OLI imagery." Jurnal Manajemen Hutan Tropika (Journal of Tropical Forest Management) 27, no. 1 (April 4, 2021): 50–58. http://dx.doi.org/10.7226/jtfm.27.1.50.
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Canopy cover is one of the most important variables in ecology, hydrology, and forest management, and useful as a basis for defining forests. LiDAR is an active remote sensing method that provides the height information of an object in three-dimensional space. The method allows for the mapping of terrain, canopy height and cover. Its only setback is that it has to be integrated with Landsat to cover a large area. The main objective of this study is to generate the canopy cover estimation model using Landsat 8 OLI and LiDAR. Landsat 8 OLI vegetation indices and LiDAR-derived canopy cover estimation, through First Return Canopy Index (FRCI) method, were used to obtain a regression model. The performance of this model was then assessed using correlation, aggregate deviation, and raster display. Lastly, the best canopy cover estimation was obtained using equation, FRCI = 2.22 + 5.63Ln(NDVI), with R2 at 0.663, standard deviation at 0.161, correlation between actual and predicted value at 0.663, aggregate deviation at -0.182 and error at 56.10%.
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Yu, Tianyu, Wenjian Ni, Zhiyu Zhang, Qinhuo Liu, and Guoqing Sun. "Regional Sampling of Forest Canopy Covers Using UAV Visible Stereoscopic Imagery for Assessment of Satellite-Based Products in Northeast China." Journal of Remote Sensing 2022 (January 10, 2022): 1–14. http://dx.doi.org/10.34133/2022/9806802.
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Canopy cover is an important parameter affecting forest succession, carbon fluxes, and wildlife habitats. Several global maps with different spatial resolutions have been produced based on satellite images, but facing the deficiency of reliable references for accuracy assessments. The rapid development of unmanned aerial vehicle (UAV) equipped with consumer-grade camera enables the acquisition of high-resolution images at low cost, which provides the research community a promising tool to collect reference data. However, it is still a challenge to distinguish tree crowns and understory green vegetation based on the UAV-based true color images (RGB) due to the limited spectral information. In addition, the canopy height model (CHM) derived from photogrammetric point clouds has also been used to identify tree crowns but limited by the unavailability of understory terrain elevations. This study proposed a simple method to distinguish tree crowns and understories based on UAV visible images, which was referred to as BAMOS for convenience. The central idea of the BAMOS was the synergy of spectral information from digital orthophoto map (DOM) and structural information from digital surface model (DSM). Samples of canopy covers were produced by applying the BAMOS method on the UAV images collected at 77 sites with a size of about 1.0 km2 across Daxing’anling forested area in northeast of China. Results showed that canopy cover extracted by the BAMOS method was highly correlated to visually interpreted ones with correlation coefficient (r) of 0.96 and root mean square error (RMSE) of 5.7%. Then, the UAV-based canopy covers served as references for assessment of satellite-based maps, including MOD44B Version 6 Vegetation Continuous Fields (MODIS VCF), maps developed by the Global Land Cover Facility (GLCF) and by the Global Land Analysis and Discovery laboratory (GLAD). Results showed that both GLAD and GLCF canopy covers could capture the dominant spatial patterns, but GLAD canopy cover tended to miss scattered trees in highly heterogeneous areas, and GLCF failed to capture non-tree areas. Most important of all, obvious underestimations with RMSE about 20% were easily observed in all satellite-based maps, although the temporal inconsistency with references might have some contributions.
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Abu Bakar, Azinoor Azida, Zulkiflee Abd Latif, and Wei-Koon Lee. "COMPARISON OF CANOPY COVER EFFECTS ON RAINFALL INTERCEPTION LOSS IN TROPICAL FOREST WITH HOMOGENOUS AND MIXED TREE SPECIES." Jurnal Teknologi 85, no. 2 (February 23, 2023): 1–9. http://dx.doi.org/10.11113/jurnalteknologi.v85.17661.
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This study was designed to determine the canopy cover, c of the tropical forest and explore its effects on the interception loss amount. The study area was a reserved forest Lagong Hill Forest Reserve, Kepong, Selangor, Malaysia, where two plots with an area of 400 m2 (20 m x 20 m) each have been set up to collect the data. In order to determine the measured interception loss, rainfall, throughfall, and stemflow data have been measured on site. The tree with a diameter at breast height (dbh) of more than 10 cm was selected in collecting the stemflow data. Twenty-five (25) locations have been chosen for the digital hemispherical photographs to be taken. The forest standing of the study area has been visualised by Stand Visualization System (SVS) method, and WinSCanopy 2009a and RGBFisheye.exe application software has been used to obtain the canopy cover values. In this study, the correlation between canopy cover and interception loss were obtained for both plots. It is found that the Lagong Hill Forest Reserve varied has a compact canopy density with canopy cover up to 95%. This condition will affect the canopy interception loss value ranging from 24.83% up to 64.72%. The canopy cover and interception loss correlation denote that the interception loss amount reduces whilst the canopy cover increases.
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Vasconcelos, Vitor Vieira, and Helenice Maria Sacht. "Influence of Canopy Cover on Surface Temperature." Revista Brasileira de Geografia Física 13, no. 07 (December 11, 2020): 3275. http://dx.doi.org/10.26848/rbgf.v13.07.p3275-3286.
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Trees affect the microclimate, which influences thermal comfort and ecosystem processes. This study investigated the influence of the canopy cover on daily maximum and minimum temperatures. The data are from a collaborative database, and each measurement consists of the minimum and maximum temperatures under the canopy and in an open adjacent area over a 24-hour period. Paired sample t-tests indicated that the canopy decreased the maximum and minimum daily temperatures and narrowed the daily temperature range. Multiple regression showed that the canopy cover percentage decreased the maximum daily temperatures, and this effect was greater in rural areas than in urbanized areas. Another multiple regression indicated that the canopy cover percentage and the distance to the edge of the canopy decreased the daily temperature range. An independent sample t-test also indicated that the effect of the canopy on the daily temperature range was higher in rural areas when analysed by parametric and non-parametric tests but not when measured by a robust test. Other independent sample t-tests indicated that the distance from a light source also decreased the canopy effect on the minimum daily temperature and the daily temperature range. The main plausible underlying processes include the canopy shade and wind insulation, litter insulation of the ground surface, heat pumps through evapotranspiration and lateral heat fluxes from light bulbs and other anthropogenic sources, especially in urbanized areas. These results provide a greater understanding of the effects of arborization in rural and urban ecosystems, as well as their respective benefits to human communities.
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Rossi, Fernando, Andreas Fritz, and Gero Becker. "Combining Satellite and UAV Imagery to Delineate Forest Cover and Basal Area after Mixed-Severity Fires." Sustainability 10, no. 7 (June 28, 2018): 2227. http://dx.doi.org/10.3390/su10072227.
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In northern Argentina, the assessment of degraded forests is a big challenge for both science and practice, due to their heterogeneous structure. However, new technologies could contribute to mapping post-disturbance canopy cover and basal area in detail. Therefore, this research assesses whether or not the inclusion of partial cover unmanned aerial vehicle imagery could reduce the classification error of a SPOT6 image used in an area-based inventory. BA was calculated from 77 ground inventory plots over 3944 ha of a forest affected by mixed-severity fires in the Argentinian Yungas. In total, 74% of the area was covered with UAV flights, and canopy height models were calculated to estimate partial canopy cover at three tree height classes. Basal area and partial canopy cover were used to formulate the adjusted canopy cover index, and it was calculated for 70 ground plots and an additional 20 image plots. Four classes of fire severity were created based on basal area and adjusted canopy cover index, and were used to run two supervised classifications over a segmented (algorithm multiresolution) wall-to-wall SPOT6 image. The comparison of the Cohan’s Kappa coefficient of both classifications shows that they are not significantly different (p-value: 0.43). However, the approach based on the adjusted canopy cover index achieved more homogeneous strata (Welch t-test with 95% of confidence). Additionally, UAV-derived canopy height model estimates of tree height were compared with field measurements of 71 alive trees. The canopy height models underestimated tree height with an RMSE ranging from 2.8 to 8.3 m. The best accuracy of the canopy height model was achieved using a larger pixel size (10 m), and for lower stocked plots due to high fire severity.
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Mõistus, Marta, Mait Lang, and Allan Sims. "Puittaimestiku kaardistamine aerolidari andmete põhjal metsana lisanduvatel aladel/ Estimation of fractional forest cover from airborne laser scanning data in abandoned agricultural land." Forestry Studies 59, no. 1 (December 1, 2013): 45–58. http://dx.doi.org/10.2478/fsmu-2013-0010.
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Abstract The abandonment of agricultural land is an actual problem in Estonia due to significant impact on landscape ecology and structure. Abandoned agricultural fields are usually converting into forest. Mapping of agricultural land use is a strategic interest of each country. Airborne laser scanning (ALS) is used in many countries for topographical mapping and the laser pulse return positions are promising datasets for mapping the abandonment of agricultural land. We used ALS data based woody plant canopy cover estimates made at certain reference height unachievable for field crops to map abandoned agricultural land in nine test sites in Tartumaa, Estonia. The maximum height of trees in test sites ranged from 6.5 m to 13.4 m. The lidar pulse returns based canopy cover estimate was assessed 1) by using ortophoto based digitized maps of tree canopy, 2) repeated measurements made with plant canopy analyzer LAI-2000 and 3) by using allometric crown radius models and repeated tree measurements from sample plots. The interpretation of canopy boundaries and separation of small spaces between tree crowns from ortophotos is a challenging task for an operator. The relationship between ALS based canopy cover and ortophoto based canopy cover was linear in all test sites except when ALS data from beginning of June were used. It the beginning of June foliage is not fully developed on trees. An increase in the woody canopy cover was detected from repeated LAI-2000 measurements and also from repeated tree measurements-based simulated crowns. The impact of reference height change from 2.0 m to 1.3 m on canopy cover estimations was not significant and much smaller compared to the tree growth induced increase in canopy cover, indicating that similar errors originating from e.g. digital elevation model are not problematic for the proposed method in practical applications.
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Smith, Janice, Charles Raczkowski, and Marihelen Kamp-Glass. "A Simple Method for Measuring Crop Canopy." HortScience 30, no. 4 (July 1995): 862F—862. http://dx.doi.org/10.21273/hortsci.30.4.862f.
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Crop canopy cover data is used to study canopy structure and crop growth analysis. This study was conducted to determine the easiest and most reliable method of calculating crop canopy cover. Using Decagon Sunfleck Ceptometer was compared with the traditional method (tape measure) of retrieving crop canopy cover data. Data was collected on silage corn (Zea mays) and soybeans (Glycine max L.). The method of collecting data using the ceptometer was simple and quick compared to the traditional method. The ceptometer, even with human variability, was found to be ≈99% accurate. The traditional method was found to have >10% variability. The ceptometer is a much quicker and more reliable tool to use. It appears to decrease the variability in the collection of crop canopy cover data.
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Kong, Seong-Pil, Hyun-Seung Song, Yang-Dam Eo, Yong-Min Kim, and Chang-Jae Kim. "LOS Analysis Simulation considering Canopy Cover." Journal of Korean Society for Geospatial Information System 20, no. 2 (June 30, 2012): 55–61. http://dx.doi.org/10.7319/kogsis.2012.20.2.055.
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Heynen, Nikolas C., and Greg Lindsey. "Correlates of Urban Forest Canopy Cover." Public Works Management & Policy 8, no. 1 (July 2003): 33–47. http://dx.doi.org/10.1177/1087724x03008001004.
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Armbrust, D. V. "Rapid Measurement of Crop Canopy Cover." Agronomy Journal 82, no. 6 (November 1990): 1170–71. http://dx.doi.org/10.2134/agronj1990.00021962008200060030x.
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Stenberg, Pauline, Lauri Korhonen, and Miina Rautiainen. "A relascope for measuring canopy cover." Canadian Journal of Forest Research 38, no. 9 (September 2008): 2545–50. http://dx.doi.org/10.1139/x08-081.
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Angle count or relascope sampling has traditionally been used in forestry to estimate stand basal area. In this paper, we present an extension to the basal area relascope, the crown relascope, which differs from the normal relascope in that the relascope’s slot is very high and wide. We describe the theoretical basis of the instrument and present results from a field test in which a crown relascope with a basal area factor of 250 m2/ha (0.025) was used to estimate canopy cover of 73 sample plots in northern Finland. The crown relascope estimates had a root mean square difference of 9.3% and an average difference of –3.1% when compared with estimates obtained with the control method, line intersect sampling using the Cajanus tube. The results indicated that the crown relascope is a quick and fairly reliable instrument for canopy cover estimation, especially in relatively sparse forests where crown overlap is insignificant and visibility does not limit an efficient use of the instrument.
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Rankin, W. T., and Elliot J. Tramer. "Understory succession and the gap regeneration cycle in a Tsuga canadensis forest." Canadian Journal of Forest Research 32, no. 1 (January 1, 2002): 16–23. http://dx.doi.org/10.1139/x01-168.
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We examined understory succession in current and former canopy gaps in mature Tsuga canadensis (L.) Carrière forests in southeastern Ohio. First, we reconstructed understory succession in current gaps by sampling 28 gaps ranging from 0 to 9 years. Second, we reconstructed the gap history of a single Tsuga community by clustering release events evident in the growth rings of 156 trees. The two reconstructions formed an 80-year chronosequence, allowing us to examine both short-term effects of gaps as well as long-term effects of closed-canopy conditions on eight common understory species. Understory cover was highest in canopy gaps. All eight understory species in the study exhibited higher cover in canopy gaps than beneath the closed Tsuga canopy. In addition, one species increased percent biomass allocated towards shoots. Although most species increased cover in gaps, different species reached peak cover at different times during gap succession. Understory species reaching peak cover early in the life of the gap were also present beneath the closed canopy and invested primarily in lateral biomass. Understory species reaching peak cover late in the life of the gap, however, were confined to gaps and invested primarily in vertical biomass. Understory cover declined during gap closure; this decline was most pronounced 20 years following gap formation. Thereafter, total understory cover increased slightly, although never to gap levels.
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Wu, Xiangqian, Xin Shen, Lin Cao, Guibin Wang, and Fuliang Cao. "Assessment of Individual Tree Detection and Canopy Cover Estimation using Unmanned Aerial Vehicle based Light Detection and Ranging (UAV-LiDAR) Data in Planted Forests." Remote Sensing 11, no. 8 (April 14, 2019): 908. http://dx.doi.org/10.3390/rs11080908.
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Canopy cover is a key forest structural parameter that is commonly used in forest inventory, sustainable forest management and maintaining ecosystem services. Recently, much attention has been paid to the use of unmanned aerial vehicle (UAV)-based light detection and ranging (LiDAR) due to the flexibility, convenience, and high point density advantages of this method. In this study, we used UAV-based LiDAR data with individual tree segmentation-based method (ITSM), canopy height model-based method (CHMM), and a statistical model method (SMM) with LiDAR metrics to estimate the canopy cover of a pure ginkgo (Ginkgo biloba L.) planted forest in China. First, each individual tree within the plot was segmented using watershed, polynomial fitting, individual tree crown segmentation (ITCS) and point cloud segmentation (PCS) algorithms, and the canopy cover was calculated using the segmented individual tree crown (ITSM). Second, the CHM-based method, which was based on the CHM height threshold, was used to estimate the canopy cover in each plot. Third, the canopy cover was estimated using the multiple linear regression (MLR) model and assessed by leave-one-out cross validation. Finally, the performance of three canopy cover estimation methods was evaluated and compared by the canopy cover from the field data. The results demonstrated that, the PCS algorithm had the highest accuracy (F = 0.83), followed by the ITCS (F = 0.82) and watershed (F = 0.79) algorithms; the polynomial fitting algorithm had the lowest accuracy (F = 0.77). In the sensitivity analysis, the three CHM-based algorithms (i.e., watershed, polynomial fitting and ITCS) had the highest accuracy when the CHM resolution was 0.5 m, and the PCS algorithm had the highest accuracy when the distance threshold was 2 m. In addition, the ITSM had the highest accuracy in estimation of canopy cover (R2 = 0.92, rRMSE = 3.5%), followed by the CHMM (R2 = 0.94, rRMSE = 5.4%), and the SMM had a relative low accuracy (R2 = 0.80, rRMSE = 5.9%).The UAV-based LiDAR data can be effectively used in individual tree crown segmentation and canopy cover estimation at plot-level, and CC estimation methods can provide references for forest inventory, sustainable management and ecosystem assessment.
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Ziter, Carly D., Eric J. Pedersen, Christopher J. Kucharik, and Monica G. Turner. "Scale-dependent interactions between tree canopy cover and impervious surfaces reduce daytime urban heat during summer." Proceedings of the National Academy of Sciences 116, no. 15 (March 25, 2019): 7575–80. http://dx.doi.org/10.1073/pnas.1817561116.
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As cities warm and the need for climate adaptation strategies increases, a more detailed understanding of the cooling effects of land cover across a continuum of spatial scales will be necessary to guide management decisions. We asked how tree canopy cover and impervious surface cover interact to influence daytime and nighttime summer air temperature, and how effects vary with the spatial scale at which land-cover data are analyzed (10-, 30-, 60-, and 90-m radii). A bicycle-mounted measurement system was used to sample air temperature every 5 m along 10 transects (∼7 km length, sampled 3–12 times each) spanning a range of impervious and tree canopy cover (0–100%, each) in a midsized city in the Upper Midwest United States. Variability in daytime air temperature within the urban landscape averaged 3.5 °C (range, 1.1–5.7 °C). Temperature decreased nonlinearly with increasing canopy cover, with the greatest cooling when canopy cover exceeded 40%. The magnitude of daytime cooling also increased with spatial scale and was greatest at the size of a typical city block (60–90 m). Daytime air temperature increased linearly with increasing impervious cover, but the magnitude of warming was less than the cooling associated with increased canopy cover. Variation in nighttime air temperature averaged 2.1 °C (range, 1.2–3.0 °C), and temperature increased with impervious surface. Effects of canopy were limited at night; thus, reduction of impervious surfaces remains critical for reducing nighttime urban heat. Results suggest strategies for managing urban land-cover patterns to enhance resilience of cities to climate warming.
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Andreu, Anne G., John I. Blake, and Stanley J. Zarnoch. "Estimating canopy fuel characteristics for predicting crown fire potential in common forest types of the Atlantic Coastal Plain, USA." International Journal of Wildland Fire 27, no. 11 (2018): 742. http://dx.doi.org/10.1071/wf18025.
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We computed four stand-level canopy stratum variables important for crown fire modelling – canopy cover, stand height, canopy base height and canopy bulk density – from forest inventory data. We modelled the relationship between the canopy variables and a set of common inventory parameters – site index, stem density, basal area, stand age or stand height – and number of prescribed burns. We used a logistic model to estimate canopy cover, a linear model to estimate the other canopy variables, and the information theoretic approach for model selection. Coefficients of determination across five forest groups were 0.72–0.91 for stand height, 0.36–0.83 for canopy base height, 0.39–0.80 for canopy cover, and 0.63–0.78 for canopy bulk density. We assessed crown fire potential (1) for several sets of environmental conditions in all seasons, and (2) with increasing age, density and number of prescribed burns using our modelled canopy bulk density and canopy base height variables and local weather data to populate the Crown Fire Initiation and Spread model. Results indicated that passive crown fire is possible in any season in Atlantic coastal plain pine stands with heavy surface fuel loads and active crown fire is most probable in infrequently burned, dense stands at low fuel moistures.
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Wasserman, Tzeidle N., Andrew J. Sánchez Meador, and Amy E. M. Waltz. "Grain and Extent Considerations Are Integral for Monitoring Landscape-Scale Desired Conditions in Fire-Adapted Forests." Forests 10, no. 6 (May 29, 2019): 465. http://dx.doi.org/10.3390/f10060465.
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Remotely-sensed data are commonly used to evaluate forest metrics, such as canopy cover, to assess change detection, and to inform land management planning. Often, canopy cover is measured only at the scale of the spatial data product used in the analysis, and there is a mismatch between the management question and the scale of the data. We compared four readily available remotely sensed landscape data products— Light detection and ranging (LiDAR), Landsat-8, Sentinel-2, and National Agriculture Imagery Program (NAIP) imagery —at different spatial grains and multiple extents to assess their consistency and efficacy for quantifying key landscape characteristics of forest canopy patches and sensitivity to change. We examined landscape-scale patterns of forest canopy cover across three landscapes in northern Arizona and assessed their performance using six landscape metrics. Changes in grain and extent affect canopy cover patch metrics and the inferences that can be made from each data product. Overall data products performed differently across landscape metrics. When performing analyses and choosing data layers, it is essential to match the scale of the data product to the management question and understand the limitations inherent in using canopy cover as a stand-alone metric.
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Akumu, Clement, Raphael Smith, and Solomon Haile. "Mapping and Monitoring the Canopy Cover and Greenness of Southern Yellow Pines (Loblolly, Shortleaf, and Virginia Pines) in Central-Eastern Tennessee Using Multi-Temporal Landsat Satellite Data." Forests 12, no. 4 (April 16, 2021): 499. http://dx.doi.org/10.3390/f12040499.
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Southern yellow pines such as loblolly, Virginia and shortleaf pines constitute forest products and contribute significantly to the economy of the United States (U.S.). However, little is understood about the temporal change in canopy cover and greenness of southern yellow pines, especially in Tennessee where they are used for timber and pulpwood. This study aims to map and monitor the canopy cover and greenness of southern yellow pines i.e., loblolly (Pinus taeda), shortleaf (Pinus echinata), and Virginia (Pinus Virginiana) pines in the years 1988, 1999 and 2016 in central-eastern Tennessee. Landsat time-series satellite data acquired in December 1988, November 1999 and February 2016 were used to map and monitor the canopy cover and greenness of loblolly, shortleaf and Virginia pines. The classification and mapping of the canopy cover of southern yellow pines were performed using a machine-learning random forest classification algorithm. Normalized Difference Vegetation Index (NDVI) was used to monitor the temporal variation in canopy greenness. In total, the canopy cover of southern yellow pines decreased by about 35% between December 1988 and February 2016. This information could be used by foresters and forest managers to support forest inventory and management.
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Buckley, David S., J. G. Isebrands, and Terry L. Sharik. "Practical Field Methods of Estimating Canopy Cover, PAR, and LAI in Michigan Oak and Pine Stands." Northern Journal of Applied Forestry 16, no. 1 (March 1, 1999): 25–32. http://dx.doi.org/10.1093/njaf/16.1.25.
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Abstract With the increased use of variables such as canopy cover, photosynthetically active radiation (PAR) and overstory leaf area index (LAI) in forestry research, relationships between these variables and traditional forestry variables must be defined before recommended levels of these research variables can be achieved by forestry practitioners on the ground. We measured basal area, canopy cover, Ozalid percent full light, PAR, and overstory LAI in thinned and unthinned plots within oak and pine stands with the objectives of: (1) determining the relationships between these variables in two common forest types, (2) investigating the feasibility of using basal area to estimate and achieve recommended levels of canopy cover, PAR, and LAI in the field, and (3) examining the possibility of using direct canopy cover and Ozalid light measurements for estimating PAR and LAI. Very strong relationships (r² > 0.90 and P < 0.0001) were indicated between basal area and canopy cover, PAR, and LAI. Direct canopy cover and Ozalid light measurements were also strongly related to PAR and LAI. It is likely that the even-aged structure of the stands studied contributed to these results. The strength of the relationships between the measures examined suggest that practical variables such as basal area could potentially be used by forestry practitioners to estimate and achieve recommended levels of canopy cover, PAR, and LAI in similar oak and pine stands. The possibility also exists for strong relationships between these variables in other stand types that resemble those studied in terms of overstory structure. North. J. Appl. For. 16(1):25-32.
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Reid, D. J., P. S. Lake, G. P. Quinn, and P. Reich. "Association of reduced riparian vegetation cover in agricultural landscapes with coarse detritus dynamics in lowland streams." Marine and Freshwater Research 59, no. 11 (2008): 998. http://dx.doi.org/10.1071/mf08012.
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Studies were conducted on streams flowing through agricultural floodplains in south-eastern Australia to quantify whether reductions in riparian canopy cover were associated with alterations to the input and benthic standing stocks of coarse allochthonous detritus. Comparisons were made among three farmland reaches and three reaches within reserves with intact cover of remnant overstorey trees. Detritus inputs to these reaches were measured monthly over 2 years using litter traps. Direct inputs to streams within the reserves were relatively high (550–617 g ash free dry weight (AFDW) m–2 year–1), but were lower at farmland reaches with the lowest canopy covers (83–117 gAFDW m–2 year–1). Only a minor fraction of the total allochthonous input (<10%) entered any of the study reaches laterally. The mean amounts of benthic detritus were lowest in the most open farmland reaches. Standing stocks of benthic detritus were found to be highly patchy across a large number of agricultural streams, but were consistently very low where the streamside canopy cover was below ~35%. Canopy cover should be restored along cleared agricultural streams because allochthonous detritus is a major source of food and habitat for aquatic ecosystems. Given the absence of pristine lowland streams in south-eastern Australia, those reaches with the most intact remnant overstorey canopies should be used to guide restoration.
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Anderson, Randy L. "Considering canopy architecture when planning cover crop mixtures." Renewable Agriculture and Food Systems 32, no. 2 (January 12, 2016): 109–11. http://dx.doi.org/10.1017/s1742170515000538.
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AbstractProducers may be able to improve growth of cover crop mixtures by selecting species to occupy different levels (zones) in the cover crop canopy. This suggestion is based on a study where we compared four cover crop treatments, comprised of one, three, six and nine species, for biomass production. Oat, dry pea and oilseed radish were present in all multi-species mixtures. Treatments were established in August, following spring wheat harvest. Biomass was harvested 9 weeks later. The most productive treatment was the oat–dry pea–oilseed radish mixture. Species of this mixture occupied different zones in the canopy and minimized interspecies competition to improve production. Cover crop mixtures of six and nine species produced 24% less biomass, which we partially attribute to unequal distribution of species in zones of the canopy. This suggestion with canopy architecture could be tested further with other cover crop species to quantify its impact.
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Coultrap, D. E., K. O. Fulgham, D. L. Lancaster, J. Gustafson, D. F. Lile, and M. R. George. "Relationships Between Western Juniper (Juniperus occidentalis) and Understory Vegetation." Invasive Plant Science and Management 1, no. 1 (January 2008): 3–11. http://dx.doi.org/10.1614/ipsm-07-008.1.
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AbstractWestern juniper has been actively invading sagebrush plant communities for about 130 yr. Western juniper canopy cover generally increases as western juniper invades sagebrush steppe communities and succession progresses toward a western juniper woodland. Our goal was to estimate the impact of juniper invasion and canopy increase on understory vegetation structure and productivity on 101 sites in northeastern California. The primary objectives of this study were to: (1) examine the influence of increasing western juniper canopy cover on the composition and productivity of understory vegetation; and (2) assess the effects of western juniper removal on understory vegetation. Sites in early, mid-, and late successional stages and sites on the same soils that had not been invaded were selected. Sites where western juniper had been removed by prescribed fire, mechanical, or chemical methods were compared to adjacent untreated sites. Western juniper canopy cover, understory cover and species composition, productivity, and bare ground were determined at each site during May through July 2005 and 2006. Regression analysis was used to evaluate the relationship between western juniper canopy cover and understory vegetation parameters. Logistic regression was used to detect understory differences between treated (juniper removed) and untreated (juniper not removed) sites. A significant relationship was found between western juniper canopy cover and understory species richness, shrub cover, forb cover, total grass cover, cheatgrass cover, herbaceous productivity, and bare ground. Removal of western juniper increased total grass cover, cheatgrass cover, and productivity, and reduced bare ground. The results of this study support findings by researchers in other states that western juniper influences plant community structure and productivity, and removal of western juniper might reverse these changes in structure, but also might increase opportunities for invasion of cheatgrass.
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Murphy, S. R., and G. M. Lodge. "Ground cover in temperate native perennial grass pastures. I. A comparison of four estimation methods." Rangeland Journal 24, no. 2 (2002): 288. http://dx.doi.org/10.1071/rj02016.
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Studies were conducted to compare visual estimates of ground cover and canopy cover by both inexperienced and experienced observers and to compare those estimates with those from more objective methods in native pastures in the high rainfall, temperate rangelands of northern NSW. Ground cover and canopy cover of 60 quadrats was estimated using visual, mapped area, digital image analysis and photo point quadrat methods. Inexperienced observers were trained by estimating ground cover of reference quadrats. Differences between mean visual estimates of ground cover and canopy cover for experienced and inexperienced observers were not significant (P>0.05). Mean ground cover estimates by the mapped area, digital image analysis and point quadrat methods were also not different from each other. The overall relationship between mean visual estimate and mean objective estimate of ground cover was non-linear (second order polynomial, R2 = 0.93), observers tending to underestimate in the mid-range (20 to 80%) of cover compared with objective methods. Mean visual estimate of ground cover was 73.7% compared with the mean objective estimate of 83.7%. Visual estimates of canopy cover (mean 34.6%) were highly correlated (R2 = 0.90) with those of the mapped area method (mean 34.3%) and the relationship was linear. Measurement of ground cover is a standard technique used in many pasture ecology and management studies and is increasingly being used by land managers to monitor pasture production and sustainability. Inexperienced observers were trained quickly and easily to estimate ground cover and canopy cover with sufficient accuracy to identify ranges of cover using visual estimation, indicating that the visual estimation technique should be suitable for estimating ground cover in land management research.
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Mathews, Bill J., Eva K. Strand, Alistair M. S. Smith, Andrew T. Hudak, B. Dickinson, and Robert L. Kremens. "Laboratory experiments to estimate interception of infrared radiation by tree canopies." International Journal of Wildland Fire 25, no. 9 (2016): 1009. http://dx.doi.org/10.1071/wf16007.
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Estimates of biomass-burning in wildfires or prescribed fires are needed to account for the production of trace gases and aerosols that enter the atmosphere during combustion. Research has demonstrated that the biomass consumption rate is linearly related to fire radiative power (FRP), and that total biomass consumed is linearly related to fire radiative energy (FRE). Measurement of these is biased by certain characteristics of a forest canopy, such as foliar moisture content and tree canopy cover. Laboratory experiments were conducted to assess the influence of canopy cover on the FRP observed from an overhead sensor (e.g. an aircraft or satellite). A range of canopy cover from 0 to 90% and two classes of canopy (non-transpiring living and desiccated branches) were used in the experiments. Experiments suggest that in cases of complete or nearly complete canopy closure, fires obscured by the canopy may be below the detection threshold of above-canopy FRP sensors. Results from this research will reduce uncertainties in estimates of biomass consumption in surface fires burning under forest canopies.
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Lang, Mait. "Estimation of crown and canopy cover from airborne lidar data." Forestry Studies / Metsanduslikud Uurimused 52, no. 1 (January 1, 2010): 5–17. http://dx.doi.org/10.2478/v10132-011-0079-5.
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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.
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Leitão, Mário de Miranda Vilas Boas Ramos, Pedro Vieira de Azevedo, Paulo César da Silva Lima, Gertrudes Macário de Oliveira, and Carlos Antonio Costa dos Santos. "Influence of Plastic Covering on the Microclimate in Vineyards in the São Francisco River Valley Region." Revista Brasileira de Meteorologia 32, no. 3 (September 2017): 399–407. http://dx.doi.org/10.1590/0102-77863230007.
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Abstract Data from field experiments conducted in table grape vineyards variety of Festival in Petrolina-PE in the period from September 19 to October 12, 2010 were used to evaluate the influence of plastic cover on microclimate conditions of vineyards in São Francisco River Valley region. Three treatments were studied: canopies without plastic cover (WC); with plastic cover positioned at 50 cm (PC50), and at 100 cm (PC100) above canopy. The results indicate that the plastic cover prevented the passage of about 40% of the global and net radiation, retained the relative humidity inside the canopy, generated an increase of air temperature and marked reduction in wind speed over the canopy of treatment PC50. However, treatment PC100 had a higher incidence of short wavelength and net radiation under canopy (on the berries) than WC and PC50 treatments, resulting in more favorable weather conditions, providing about 40% greater productivity in this treatment. Therefore, the vineyard with plastic cover placed at 100 cm above canopy represents a more suitable alternative to the climatic conditions of the region of the São Francisco River Valley.
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Tinambunan, Shintani Asri, Nyoman Dati Pertami, and Ni Made Ernawati. "Percentage of Mangrove Canopy Cover and Mollusks Abundance in Benoa Bay Mangrove Ecosystem." Advances in Tropical Biodiversity and Environmental Sciences 5, no. 3 (October 31, 2021): 105. http://dx.doi.org/10.24843/atbes.2021.v05.i03.p05.
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This research was conducted to determine the condition of the mangrove ecosystem based on its canopy cover and to determine the types of mollusks (Bivalves and Gastropods) associated with the Benoa Bay mangrove ecosystem. Hemispherical photography is a method for observing mangrove canopy cover and line transect method for mollusks. The composition of mangrove species found in the research location were five species, namely Rhizophora stylosa, Rhizophora mucronata, Rhizophora apiculata, Bruguiera gymnorrhiza, and Avicennia marina. The percentage of mangrove canopy cover in the Benoa Bay mangrove ecosystem is in a good category (average = 76.59%). There are eight types of mollusks found in the research location. There are two types of bivalves (Polymesoda bengalensis and Gafrarium pectinatum) and six types of gastropods (Nerita balteata, Nerita picea, Neritina turrita, Pila ampullacea, Cassidula aurisfelis, and Littoraria melanostoma). The relationship between the percentage of mangrove canopy cover and abundance of mollusks in the Benoa Bay mangrove ecosystem is very strong (r) of 0.920. The higher the percentage value of mangrove canopy cover, the higher the mollusks abundance.
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Uieda, VS, and EM Carvalho. "Experimental manipulation of leaf litter colonization by aquatic invertebrates in a third order tropical stream." Brazilian Journal of Biology 75, no. 2 (May 2015): 405–13. http://dx.doi.org/10.1590/1519-6984.15013.
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Through a manipulative experiment, the colonization of leaf litter by invertebrates was investigated in two sections of a tropical stream (spatial scale) that differed in function of the canopy cover, one with the presence (closed area) and another without riparian vegetation (open area), during one month of the dry and one of the wet season (temporal scale). The work aimed to verify differences related to four variables: season, canopy cover, leaf type and leaf condition. Litter bags containing arboreal and herbaceous leaves (leaf type variable), non-conditioned and preconditioned (leaf condition variable) were placed at the bottom of the stream in each area (canopy cover variable) and season (dry and wet), and removed after 13-day colonization. The analysis of the remaining litter dry mass per leaf bag emphasizes differences related mainly to seasonality, canopy cover and leaf type, although leaf condition was also important when combined with those three factors. Comparing the abundance of invertebrates per treatment, there was a tendency of high predominance of Chironomidae during the dry season and greater taxa diversity and evenness during the wet season, when the water flow increase could alter the availability of microhabitats for local fauna. Even though canopy cover alone was not a significant source of variation in the abundance of invertebrates, the results showed a tendency of a combined effect of canopy cover with seasonality and leaf condition.