Estimating forest canopy bulk density using six indirect methods

2005 ◽  
Vol 35 (3) ◽  
pp. 724-739 ◽  
Author(s):  
Robert E Keane ◽  
Elizabeth D Reinhardt ◽  
Joe Scott ◽  
Kathy Gray ◽  
James Reardon
Keyword(s):  
Bulk Density ◽  
Forest Canopy ◽  
Research Effort ◽  
Measurement Techniques ◽  
Horizontal Distribution ◽  
Regression Equations ◽  
Plant Canopy ◽  
Hemispherical Photography ◽  
Biomass Components ◽  
Canopy Bulk Density

Canopy bulk density (CBD) is an important crown characteristic needed to predict crown fire spread, yet it is difficult to measure in the field. Presented here is a comprehensive research effort to evaluate six indirect sampling techniques for estimating CBD. As reference data, detailed crown fuel biomass measurements were taken on each tree within fixed-area plots located in five important conifers types in the western United States, using destructive sampling following a series of four sampling stages to measure the vertical and horizontal distribution of canopy biomass. The six ground-based indirect measurement techniques used these instruments: LI-COR LAI-2000, AccuPAR ceptometer, CID digital plant canopy imager, hemispherical photography, spherical densiometer, and point sampling. These techniques were compared with four aggregations of crown biomass to compute CBD: foliage only, foliage and small branchwood, foliage and all branchwood (no stems), and all canopy biomass components. Most techniques had the best performance when all canopy biomass components except stems were used. Performance dropped only slightly when the foliage and small branchwood canopy biomass aggregation (best approximates fuels available for crown fires) was employed. The LAI-2000, hemispherical photography, and CID plant canopy imager performed best. Regression equations that predict CBD from gap fraction are presented for all six techniques.

Evaluating regression model estimates of canopy fuel stratum characteristics in four crown fire-prone fuel types in western North America

2012 ◽  
Vol 21 (2) ◽  
pp. 168 ◽  
Author(s):  
Miguel G. Cruz ◽  
Martin E. Alexander
Keyword(s):  
North America ◽  
Bulk Density ◽  
Ponderosa Pine ◽  
Stand Structure ◽  
Coniferous Forest ◽  
Fuel Load ◽  
Regression Equations ◽  
Western North America ◽  
Crown Fire ◽  
Canopy Bulk Density

Two evaluations were undertaken of the regression equations developed by M. Cruz, M. Alexander and R. Wakimoto (2003, International Journal of Wildland Fire 12, 39–50) for estimating canopy fuel stratum characteristics from stand structure variables for four broad coniferous forest fuel types found in western North America. The first evaluation involved a random selection of 10 stands each from the four datasets used in the original study. These were in turn subjected to two simulated thinning regimes (i.e. 25 and 50% basal area removal). The second evaluation involved a completely independent dataset for ponderosa pine consisting of 16 stands sampled by T. Keyser and F. Smith (2010, Forest Science 56, 156–165). Evaluation statistics were comparable for the thinning scenarios and independent evaluations. Mean absolute percentage errors varied between 13.8 and 41.3% for canopy base height, 5.3 and 67.9% for canopy fuel load, and 20.7 and 71% for canopy bulk density. Bias errors were negligible. The results of both evaluations clearly show that the stand-level models of Cruz et al. (2003) used for estimating canopy base height, canopy fuel load and canopy bulk density in the assessment of crown fire potential are, considering their simplicity, quite robust.

Deriving forest canopy fuel parameters for loblolly pine forests in eastern Texas

2011 ◽  
Vol 41 (8) ◽  
pp. 1618-1625 ◽  
Author(s):  
Muge Agca ◽  
Sorin C. Popescu ◽  
Clinton W. Harper
Keyword(s):  
Bulk Density ◽  
Loblolly Pine ◽  
Forest Fires ◽  
Forest Canopy ◽  
Forest Type ◽  
Practical Method ◽  
Allometric Equation ◽  
Average Height ◽  
Pinus Taeda L ◽  
Canopy Bulk Density

Crown fires, the fastest spreading of all forest fires, can occur in any forest type throughout the world. The overall aim of this study was to estimate forest canopy fuel parameters including canopy bulk density and canopy base height for loblolly pines ( Pinus taeda L.) at the plot level using both allometric equations and CrownMass/FMAPlus software. Allometric equation results were compared with the CrownMass outputs for validation. According to our results, the calculated average canopy bulk density values, across all 50 plots, were 0.18 and 0.07 kg/m3 for the allometric equation and the CrownMass program, respectively. Lorey’s mean height approach was used in this study to calculate canopy base height at the plot level. The average height values of canopy base height obtained from the Lorey height approach was 10.6 m and from the CrownMass program was 9.1 m. The results obtained for the two methods are relatively close to each other, with the estimate of canopy base height being 1.16 times larger than the CrownMass value. This study provides a practical method for quantifying these parameters and making them directly available to fire managers. The accuracy of these parameters is very important for realistic predictions of wildfire initiation and growth.

Differential Bone-Refuse Accumulation in Food-Preparation and Traffic Areas on an Early Ecuadorian House Floor

1990 ◽  
Vol 1 (2) ◽  
pp. 150-169 ◽  
Author(s):  
Peter W. Stahl ◽  
James A. Zeidler
Keyword(s):  
Bulk Density ◽  
Surface Area ◽  
Fish Bone ◽  
Horizontal Distribution ◽  
Total Weight ◽  
Food Preparation ◽  
Large Size ◽  
Traffic Area ◽  
High Concentrations ◽  
House Floor

Ethnographic observations of floor formation in an occupied and an abandoned Achuar jea dwelling structure are combined with contemporary taphonomic studies of swept and trampled surfaces. These studies suggest that refuse accumulation and incorporation are markedly different in food-preparation areas with ash deposits around fixed hearth features when compared to regularly trampled traffic areas of domestic earthen house floors. These points are examined in the horizontal and vertical analysis of highly fragmented bone remains in an Early Formative domestic house floor at the site of Real Alto, in the coastal lowlands of southwestern Ecuador. The food-preparation area of the Structure 1 house floor contained high concentrations of bone specimens characterized by their large size (over 25 mm), broad surface area, low bulk density, and greater total weight, vertically distributed throughout the ash matrix. The traffic area contained bone specimens characterized by their small size (under 25 mm), narrow surface area, high bulk density, and lower total weight, distributed unevenly in vertical profile. The horizontal distribution of fish bone only partially followed the observed pattern, as a proportionately greater amount of large fish bone was located in the traffic area. This analysis demonstrates the potential utility of bone refuse as a sensitive and reliable taphonomic indicator for inferential arguments regarding house-floor deposition.

scholarly journals Effect of Different Extrusion Processing Parameters on Physical Properties of Soy White Flakes and High Protein Distillers Dried Grains-Based Extruded Aquafeeds

2014 ◽  
Vol 3 (6) ◽  
pp. 107 ◽  
Author(s):  
Sushil K. Singh ◽  
K. Muthukumarappan
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Bulk Density ◽  
Water Solubility ◽  
Expansion Ratio ◽  
High Protein ◽  
Regression Equations ◽  
Process Variables ◽  
Distillers Dried Grains ◽  
Durability Index

<p>Nutritionally balanced ingredient blends for catla (<em>Catla catla</em>), belonging to the family Cyprinidae, were extruded using single screw extruder. The extrusion was carried out at five levels of soy white flakes content (21%, 29%, 40%, 52%, and 59% db), five levels of moisture content (15, 19, 25, 31, and 35% db) and five levels of barrel temperature (100, 110, 125, 140, and 150 ºC) using three different die nozzles (having L/D ratios 3.33, 5.83, and 7.25). Blends with net protein content of 32.5% contains soy white flakes, along with high protein distillers dried grains (HP-DDG), corn flour, corn gluten meal, fish meal, vitamin, and mineral mix. A central composite rotatable design (CCRD) and  response surface methodology (RSM) was used to investigate the significance of independent and interaction effects of the extrusion process variables on the extrudates physical properties namely pellet durability index, bulk density, water absorption and solubility indices and expansion ratio. Quadratic polynomial regression equations were developed to correlate the product responses and process variables as well as to obtain the response surfaces plots. The independent variables had significant (<em>P </em>&lt; 0.05) effects on physical properties of extrudates: (i) higher soy white flakes content increased the pellet durability index and water absorption index, but decreased the water solubility index, (ii) higher temperature decreased pellet durability index, bulk density and water solubility index, (iii) increased L/D ratio from 3.33 to 7.25 increased the pellet durability index, expansion ratio but decreased the bulk density of the extrudates.</p>

scholarly journals Optimizing smartphone-based canopy hemispherical photography

2021 ◽  
Author(s):  
Gastón Mauro Díaz
Keyword(s):  
Large Scale ◽  
Forest Canopy ◽  
Accuracy Assessment ◽  
Low Cost ◽  
R Package ◽  
Coefficient Of Determination ◽  
Native Forest ◽  
Hemispherical Photography ◽  
Area Index ◽  
Plant Area Index

1) Hemispherical photography (HP) is a long-standing tool for forest canopy characterization. Currently, there are low-cost fisheye lenses to convert smartphones into high-portable HP equipment; however, they cannot be used whenever since HP is sensitive to illumination conditions. To obtain sound results outside diffuse light conditions, a deep-learning-based system needs to be developed. A ready-to-use alternative is the multiscale color-based binarization algorithm, but it can provide moderate-quality results only for open forests. To overcome this limitation, I propose coupling it with the model-based local thresholding algorithm. I call this coupling the MBCB approach. 2) Methods presented here are part of the R package CAnopy IMage ANalysis (caiman), which I am developing. The accuracy assessment of the new MBCB approach was done with data from a pine plantation and a broadleaf native forest. 3) The coefficient of determination (R^2) was greater than 0.7, and the root mean square error (RMSE) lower than 20 %, both for plant area index calculation. 4) Results suggest that the new MBCB approach allows the calculation of unbiased canopy metrics from smartphone-based HP acquired in sunlight conditions, even for closed canopies. This facilitates large-scale and opportunistic sampling with hemispherical photography.

scholarly journals Estimation of forest canopy cover: a comparison of field measurement techniques

Silva Fennica ◽  
2006 ◽  
Vol 40 (4) ◽  
Author(s):  
Lauri Korhonen ◽  
Kari Korhonen ◽  
Miina Rautiainen ◽  
Pauline Stenberg
Keyword(s):  
Field Measurement ◽  
Forest Canopy ◽  
Measurement Techniques ◽  
Canopy Cover

scholarly journals Study of Subtropical Forestry Index Retrieval Using Terrestrial Laser Scanning and Hemispherical Photography

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Ting Yun ◽  
Weizheng Li ◽  
Yuan Sun ◽  
Lianfeng Xue
Keyword(s):  
Laser Scanning ◽  
Estimation Method ◽  
Terrestrial Laser Scanning ◽  
Tangent Plane ◽  
Transfer Model ◽  
Normal Vector ◽  
Plant Canopy ◽  
Hemispherical Photography ◽  
Area Index ◽  
Cloud Data

In order to retrieve gap fraction, leaf inclination angle, and leaf area index (LAI) of subtropical forestry canopy, here we acquired forestry detailed information by means of hemispherical photography, terrestrial laser scanning, and LAI-2200 plant canopy analyzer. Meanwhile, we presented a series of image processing and computer graphics algorithms that include image and point cloud data (PCD) segmentation methods for branch and leaf classification and PCD features, such as normal vector, tangent plane extraction, and hemispherical projection method for PCD coordinate transformation. In addition, various forestry mathematical models were proposed to deduce forestry canopy indexes based on the radiation transfer model of Beer-Lambert law. Through the comparison of the experimental results on many plot samples, the terrestrial laser scanner- (TLS-) based index estimation method obtains results similar to digital hemispherical photograph (HP) and LAI-2200 plant canopy analyzer taken of the same stands and used for validation. It indicates that the TLS-based algorithm is able to capture the variability in LAI of forest stands with a range of densities, and there is a high chance to enhance TLS as a calibration tool for other devices.

Properties of Dan Kwian, Sukhothai and Ratchaburi Pottery Clays Fired at 700 and 900 °C

2014 ◽  
Vol 608 ◽  
pp. 47-61
Author(s):  
Nonglak Meethong ◽  
Wanwisa Pattanasiriwisawa ◽  
Weenawan Somphon ◽  
Waraporn Tanthanuch ◽  
Sutham Srilomsak
Keyword(s):  
Specific Gravity ◽  
Comparative Study ◽  
Water Absorption ◽  
Bulk Density ◽  
Firing Temperature ◽  
Reflectance Spectra ◽  
Modulus Of Rupture ◽  
Regression Equations ◽  
Statistical Software

Dan Kwian, Sukhothai and Ratchaburi pottery clays are economically important pottery clays. They are well known in the Thai ceramic society for making Dan Kwian pottery, Sawankhalok pottery and Dragon jars, respectively. There have been several studies of these pottery clays. However, few of them used statistics to analyze their results. This work is a comparative study of the compositions and properties of these three pottery clays using statistical software to analyze the results. Results show that the major components of these pottery clays are SiO2 and Al2O3. The Modulus of Rupture (MOR) of each pottery clay fired at 700°C are not significantly different. Sukhothai pottery clay fired at 900°C has a higher MOR and bulk density while its porosity, water absorption and apparent specific gravity are less than those of the Dan Kwian and Ratchaburi pottery clays fired at the same temperature. Additionally, the current study developed regression equations for estimating the properties of all pottery clays under study. Finally, it was found that the L*, a*, b* and reflectance spectra of all pottery clays increased when firing temperature was increased from 700 to 900°C.

LABORATORY DETERMINATION OF FIELD BULK DENSITY FOR IMPROVING FERTILIZER RECOMMENDATIONS OF ORGANIC SOILS

1981 ◽  
Vol 61 (3) ◽  
pp. 475-482 ◽  
Author(s):  
W. VAN LIEROP
Keyword(s):  
Bulk Density ◽  
Accurate Method ◽  
Organic Soils ◽  
Soil Test ◽  
Regression Equations ◽  
Exponential Relationship ◽  
Fertilizer Recommendations ◽  
Regression Techniques ◽  
Soil Fertilizer

The objectives of this study were to find ways to improve the accuracy of soil fertilizer recommendations by taking into account the variation in bulk density (BD) of organic soils. To achieve this end, field BD values of 30 organic soils (0.100–0.504 g/mL) were used to evaluate methods of measuring the BD in the laboratory by means of correlation and regression techniques. A simple and rapid procedure using the reconstituted BD of field-moist soils was the most accurate means of determining the average field BD in the laboratory, as indicated by the correlation coefficient obtained between the BD values obtained by this method and those in the field (r = 0.975**). The second most accurate method relied upon the exponential relationship between the water content of soils and their BD (R2 = 91.1 %). The least exact method of correcting for BD variations was to scoop a volume of dried (65 °C) and sieved (2-mm) soils, as is done in some soil test laboratories. Although the values obtained by this method were related (r = 0.502**) to the field data, drying caused shrinkage of soils, thereby increasing their BD about twofold. Soil pH (r = 0.716**) and percentage ash contents (r = 0.851**) were also related to the field BD of soils. These tests could be used to estimate the BD of soils when the preferred method cannot be used. Regression equations are provided for relating appropriate test values to the BD of organic soils.

Estimating canopy fuel characteristics for predicting crown fire potential in common forest types of the Atlantic Coastal Plain, USA

2018 ◽  
Vol 27 (11) ◽  
pp. 742 ◽  
Author(s):  
Anne G. Andreu ◽  
John I. Blake ◽  
Stanley J. Zarnoch
Keyword(s):  
Bulk Density ◽  
Coastal Plain ◽  
Canopy Cover ◽  
Atlantic Coastal Plain ◽  
Theoretic Approach ◽  
Crown Fire ◽  
Prescribed Burns ◽  
Stand Height ◽  
Atlantic Coastal ◽  
Canopy Bulk Density

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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