STRUCTURE ANALYSIS AND BIOMASS MODELS FOR PLUM TREE (PRUNUS DOMESTICA L.) IN ECUADOR

The development of dendrometric methodologies could allow accurate estimation of variables associated with the crown, such as primary production (fruit and timber) and tree vigor. The aim of this work was to develop a suitable method to estimate woody biomass in plum trees (Prunus domestica L.) in Imbabura, Ecuador by using an adapted dendrometry. Form factors and regression models were defined for branch volume calculation. From this, the distribution of woody biomass in the crown tree was characterized in every stratum. Occupation Factor and regression models were obtained in order to calculate the biomass in the crown tree, which can be used to estimate the CO2 captured in its structure during its development. Regression models for calculation of whole volume of the tree and pruned biomass were directly obtained from crown diameter and crown height with Rajustated 2 of 0.74 and 0.81. The average moisture content of green material was 51%, and the average density of dry material was 0.66 ± 0.07 g cm−3. Proximate analysis of plum wood showed at 79.8 ± 9.2% volatiles and 2.1 ± 0.3% ash. Elemental analysis of the wood pointed to 46.5 ± 1.2% C, 6.1 ± 0.5% H, 46.3 ± 1.2% O, 0.6 ± 0.3% N, 0.06 ± 0.02% S and 0.02 ± 0.01% Cl. Cl, S and N contents are lower than the limits established by the standard EN 14691-part 4.With 46% of C, considering the relation 3.67 (44/12) between CO2 and C content, the CO2 sequestrated in the materials is 1.11 Mg m−3 wood material. Such method represents a tool to manage orchard resources and for assessing other parameters, such as raw materials for cultivation, fruit production, CO2 sink and waste materials (residual wood) used for energy or industry.The authors appreciate the financial support provided by the ECUMASA, Red ecuatoriana para la investigacion del aprovechamiento energetico de la biomasa.Velázquez Martí, B.; Cazco-Logroño, C. (2017). STRUCTURE ANALYSIS AND BIOMASS MODELS FOR PLUM TREE (PRUNUS DOMESTICA L.) IN ECUADOR. Experimental Agriculture. 54(1):133-141. https://doi.org/10.1017/S001447971600079XS133141541Velázquez-Martí, B., Estornell, J., López-Cortés, I., & Martí-Gavilá, J. (2012). Calculation of biomass volume of citrus trees from an adapted dendrometry. Biosystems Engineering, 112(4), 285-292. doi:10.1016/j.biosystemseng.2012.04.011Velázquez-Martí, B., Fernández-González, E., López-Cortés, I., & Salazar-Hernández, D. M. (2011). Quantification of the residual biomass obtained from pruning of vineyards in Mediterranean area. Biomass and Bioenergy, 35(8), 3453-3464. doi:10.1016/j.biombioe.2011.04.009Velázquez-Martí, B., Fernández-González, E., López-Cortés, I., & Salazar-Hernández, D. M. (2011). Quantification of the residual biomass obtained from pruning of trees in Mediterranean olive groves. Biomass and Bioenergy, 35(7), 3208-3217. doi:10.1016/j.biombioe.2011.04.042B. Velazquez-Marti, & E. Annevelink. (2009). GIS Application to Define Biomass Collection Points as Sources for Linear Programming of Delivery Networks. Transactions of the ASABE, 52(4), 1069-1078. doi:10.13031/2013.27776Sajdak, M., & Velazquez-Marti, B. (2012). Estimation of pruned biomass form dendrometric parameters on urban forests: Case study of Sophora japonica. Renewable Energy, 47, 188-193. doi:10.1016/j.renene.2012.04.002Pérez-Arévalo, J. J., Callejón-Ferre, A. J., Velázquez-Martí, B., & Suárez-Medina, M. D. (2015). Prediction models based on higher heating value from the elemental analysis of neem, mango, avocado, banana, and carob trees in Guayas (Ecuador). Journal of Renewable and Sustainable Energy, 7(5), 053122. doi:10.1063/1.4934593Maltamo, M. (2004). Estimation of timber volume and stem density based on scanning laser altimetry and expected tree size distribution functions. Remote Sensing of Environment, 90(3), 319-330. doi:10.1016/j.rse.2004.01.006García-Tejero, I. F., Durán-Zuazo, V. H., Arriaga, J., & Muriel-Fernández, J. L. (2012). Relationships between trunk- and fruit-diameter growths under deficit-irrigation programmes in orange trees. Scientia Horticulturae, 133, 64-71. doi:10.1016/j.scienta.2011.10.022Estornell, J., Velázquez-Martí, B., López-Cortés, I., Salazar, D., & Fernández-Sarría, A. (2014). Estimation of wood volume and height of olive tree plantations using airborne discrete-return LiDAR data. GIScience & Remote Sensing, 51(1), 17-29. doi:10.1080/15481603.2014.883209EN 14691-part 4 (2009). Solid biofuels – Fuel Specifications and classes – Wood chips for non-industrial use. 10p.Doruska, P. F., & Burkhart, H. E. (1994). Modeling the diameter and locational distribution of branches within the crowns of loblolly pine trees in unthinned plantations. Canadian Journal of Forest Research, 24(12), 2362-2376. doi:10.1139/x94-305Deckmyn, G., Evans, S. P., & Randle, T. J. (2006). Refined pipe theory for mechanistic modeling of wood development. Tree Physiology, 26(6), 703-717. doi:10.1093/treephys/26.6.703Bessou, C., Basset-Mens, C., Tran, T., & Benoist, A. (2012). LCA applied to perennial cropping systems: a review focused on the farm stage. The International Journal of Life Cycle Assessment, 18(2), 340-361. doi:10.1007/s11367-012-0502-zAndersen, H.-E., Reutebuch, S. E., & McGaughey, R. J. (2006). A rigorous assessment of tree height measurements obtained using airborne lidar and conventional field methods. Canadian Journal of Remote Sensing, 32(5), 355-366. doi:10.5589/m06-030Olson, M. E., & Rosell, J. A. (2012). Vessel diameter-stem diameter scaling across woody angiosperms and the ecological causes of xylem vessel diameter variation. New Phytologist, 197(4), 1204-1213. doi:10.1111/nph.12097Gracia, C., Velázquez-Martí, B., & Estornell, J. (2014). An application of the vehicle routing problem to biomass transportation. Biosystems Engineering, 124, 40-52. doi:10.1016/j.biosystemseng.2014.06.00

Methane Production from Slaughterhouse Waste and Wheat Straw: Influence of Concentration

The indiscriminate generation of slaughterhouse waste and agricultural waste can present pollution problems in the environment. An alternative to counteract these problems is the anaerobic digestion of waste through the production of biogas and methane as clean and renewable energy. In this sense, this study aimed to optimize methane production from anaerobic codigestion of slaughterhouse waste from cattle and wheat straw. The treatments were evaluated using anaerobic sludge as inoculum from the wastewater treatment plant of the city of Ibarra. The tests were carried out under mesophilic conditions (38°C) in digesters with a useful volume of 186 ml. The influence of the substrate concentration was evaluated by anaerobically digesting 45 samples at different concentrations (5, 10 and 15 g VS/l) with a substrate/inoculum ratio of 1:2. The highest accumulated methane yield occurred in the digesters composed of 15 g VS/l. The maximum methane production was 320.48 Nml/g VS. The kinetics of the tests were adjusted with the cone model, where there were correlations greater than 99%. Keywords: biogas, methane, codigestion, synergy, inoculum, kinetics. Resumen La generación indiscriminada de residuos de matadero y desechos agrícolas pueden presentar problemas de contaminación en el medio ambiente. Una alternativa para contrarrestar estos problemas es la digestión anaeróbica de los desechos mediante la produción de biogás y metano como energía limpia y renovable. En este sentido el objetivo de este estudio es la optimización de la producción de metano a partir de la codigestión anaeróbica de residuos de matadero de ganado vacuno y paja de trigo. Los tratamientos se evaluaron empleando como inóculo lodo anaerobio de la planta de tratamiento de aguas residuales de la ciudad de Ibarra. Los ensayos se realizaron en condiciones mesofílicas (38°C) en digestores de 186 ml de volumen útil. La influencia de la concentración del sustrato se evaluó digiriendo anaeróbicamente 45 muestras a diferentes concentraciones (5, 10 y 15 g SV/l) con una relación sustrato/inóculo de 1:2. El mayor rendimiento acumulado de metano se produjo en los digestores compuestos por 15 g SV/l. La producción máxima de metano fue de 320,48 Nml/g SV. La cinética de los ensayos se ajustó con el modelo del cono, donde se tuvo correlaciones superiores al 99%. Palabras Clave: biogás, metano, codigestión, sinergia, inóculo, cinética

Estimating residual biomass of olive tree crops using terrestrial laser scanning

[EN] Agricultural residues have gained increasing interest as a source of renewable energy. The development of methods and techniques that allow to inventory residual biomass needs to be explored further. In this study, the residual biomass of olive trees was estimated based on parameters derived from using a Terrestrial Laser Scanning System (TLS). To this end, 32 olive trees in 2 orchards in the municipality of Viver, Central Eastern Spain, were selected and measured using a TLS system. The residual biomass of these trees was pruned and weighed. Several algorithms were applied to the TLS data to compute the main parameters of the trees: total height, crown height, crown diameter and crown volume. Regarding the last parameter, 4 methods were tested: the global convex hull volume, the convex hull by slice volume, the section volume, and the volume measured by voxels. In addition, several statistics were computed from the crown points for each tree. Regression models were calculated to predict residual biomass using 3 sets of potential explicative variables: firstly, the height statistics retrieved from 3D cloud data for each crown tree, secondly, the parameters of the trees derived from TLS data and finally, the combination of both sets of variables. Strong relationships between residual biomass and TLS parameters (crown volume parameters) were found (R2 = 0.86, RMSE = 2.78 kg). The pruning biomass pre- diction fraction was improved by 6%, in terms of R2, when the variance of the crown-point elevations was selected (R2 = 0.92, RMSE = 2.01 kg). The study offers some important insights into the quantification of residual biomass, which is essential information for the production of biofuel.Fernández-Sarría, A.; López- Cortés, I.; Estornell Cremades, J.; Velázquez Martí, B.; Salazar Hernández, DM. (2019). Estimating residual biomass of olive tree crops using terrestrial laser scanning. International Journal of Applied Earth Observation and Geoinformation. 75:163-170. https://doi.org/https://doi.org/10.1016/j.jag.2018.10.019S1631707

Calculation of biomass volume of citrus trees from an adapted dendrometry

A methodology and computational algorithms, to calculate volumes and the total biomass contained in citrus trees from an adapted dendrometry were developed. The methodology could be used as a tool to manage resources from the orchards, establishing adequate predictive models for assessing parameters such as income from raw materials for the cultivation, fruit production, CO2 sink, and waste materials (i.e. residual wood) used for energy or industry. Dendrometry has been traditionally applied to forest trees. However, little research has been conducted on fruit trees due to their heterogeneous structure. To develop the process of biomass quantification it was necessary to perform systems of measurement, enabling to determine volumes of the analysed trees. Firstly, form factors and volume functions for the branches were calculated. These volume functions gave 0.97 coefficient of determination from base diameter and length. The relationships between apparent crown volume and actual volume in the crown (i.e. no hollows) of the trees were established, with 0.80 coefficient of determination. Occupation factor and the distribution of biomass in the crown strata were evaluated. These results could be correlated with production and quality of the fruit, with the amount of residual biomass coming from pruning, and with LIDAR data what may produce a simple, quick and accurate way to predict biomass.This research were developed by the project AGL2010-15334 funded by the Ministry of Science and Innovation of Spain funds.Velázquez Martí, B.; Estornell Cremades, J.; López Cortés, I.; Marti Gavila, J. (2012). Calculation of biomass volume of citrus trees from an adapted dendrometry. Biosystems Engineering. 112(4):285-292. https://doi.org/10.1016/j.biosystemseng.2012.04.011S285292112

Different methodologies for calculating crown volume of Platanus hispanica trees by terrestial laser scanner and comparison with classical dendrometric measurements

Terrestrial laser scanners (TLSs) are used in forestry and fruit culture applications to perform a threedimensional geometrical characterization of trees and so make it easier to develop management systems based on that information. In addition, this data can improve the accuracy of dendrometric variable estimations, such as crown volume, obtained by standard methods. The main objective of this paper is to compare classical methods for crown volume estimation with the volumes obtained from the processing of point clouds obtained using a terrestrial laser scanner (TLS) on urban Platanus hispanica trees. This will allow faster quantification of residual biomass from pruning and therefore an improved management in future. The methods applied using TLS data were also evaluated in terms of processing speed. A set of 30 specimens were selected and their main dendrometric parameters (such as diameter breast height, crown diameter, total height, and distance from the crown base to the soil) were manually measured using classical methods. From these dendrometric parameters, the apparent crown volumes were calculated using three geometric models: cone, hemisphere, and paraboloid. Simultaneously, these trees were scanned with a Leica ScanStation2. A laser point cloud was registered for each tree and processed to obtain the crown volumes. Four processing methods were analyzed: (a) convex hull (an irregular polyhedral surface formed by triangles that surround the crown) applied to the whole point cloud that forms the crown; (b) convex hull using slices of 10 cm in height from the top to the base of the crown; (c) XY triangulation in horizontal sections; and (d) voxel discretization. All the obtained volumes (derived from classical methods and TLS) were assessed and compared. The regression equations that compare the volumes obtained by dendrometry and those derived from TLS data showed coefficients of determination (R2) greater than 0.78. The highest R2 (0.89) was obtained in the comparison between the volume calculated using a paraboloid and flat sections, which was also the fastest method. These results show the potential of TLS for predicting the crown volumes of urban trees, such as P. hispanica, to help improve their management, especially the quantification of residual biomass.The authors appreciate the financial support provided by the Spanish Ministry of Science and Innovation in the framework of the Project AGL2010-15334 and by the Generalitat Valenciana in the framework of the Project GV/2012/003.Fernández-Sarría, A.; Martínez, L.; Velázquez Martí, B.; Sajdak, M.; Estornell Cremades, J.; Recio Recio, JA. (2013). Different methodologies for calculating crown volume of Platanus hispanica trees by terrestial laser scanner and comparison with classical dendrometric measurements. Computers and Electronics in Agriculture. 90(1):176-185. https://doi.org/10.1016/j.compag.2012.09.017S17618590

Estimation of wood volume and height of olive tree plantations using airborne discrete-return LiDAR data

The aim of this study is to analyze methodologies based on airborne LiDAR (light detection and ranging) technology of low pulse density points (0.5m(-2)) for height and volume quantification of olive trees in Viver (Spain). A total of 29 circular plots, each with a radius of 20m, were sampled and their volumes and heights were obtained by dendrometric methods. For these estimations, several statistics derived from LiDAR data were calculated in each plot. Regression models were used to predict volume and height. The results showed good performance for estimating volume (R-2=0.70) and total height (R-2=0.67).The authors appreciate the financial support provided by the Spanish Ministerio de Ciencia e Innovacion (Ministry for Science & Innovation) within the framework of the project AGL2010-15334 and by the Vice-Rectorate for Research of the Universitat Politecnica de Valencia [Grant PAID-06-12-3297; SP20120534].Estornell Cremades, J.; Velázquez Martí, B.; López Cortés, I.; Salazar Hernández, DM.; Fernández-Sarría, A. (2014). Estimation of wood volume and height of olive tree plantations using airborne discrete-return LiDAR data. GIScience and Remote Sensing. 51(1):17-29. https://doi.org/10.1080/15481603.2014.883209S1729511Estornell, J., Ruiz, L. A., Velázquez-Martí, B., & Fernández-Sarría, A. (2011). Estimation of shrub biomass by airborne LiDAR data in small forest stands. Forest Ecology and Management, 262(9), 1697-1703. doi:10.1016/j.foreco.2011.07.026García, M., Riaño, D., Chuvieco, E., & Danson, F. M. (2010). Estimating biomass carbon stocks for a Mediterranean forest in central Spain using LiDAR height and intensity data. Remote Sensing of Environment, 114(4), 816-830. doi:10.1016/j.rse.2009.11.021Hyyppa, J., Kelle, O., Lehikoinen, M., & Inkinen, M. (2001). A segmentation-based method to retrieve stem volume estimates from 3-D tree height models produced by laser scanners. IEEE Transactions on Geoscience and Remote Sensing, 39(5), 969-975. doi:10.1109/36.921414Kim, Y., Yang, Z., Cohen, W. B., Pflugmacher, D., Lauver, C. L., & Vankat, J. L. (2009). Distinguishing between live and dead standing tree biomass on the North Rim of Grand Canyon National Park, USA using small-footprint lidar data. Remote Sensing of Environment, 113(11), 2499-2510. doi:10.1016/j.rse.2009.07.010Moorthy, I., Miller, J. R., Berni, J. A. J., Zarco-Tejada, P., Hu, B., & Chen, J. (2011). Field characterization of olive (Olea europaea L.) tree crown architecture using terrestrial laser scanning data. Agricultural and Forest Meteorology, 151(2), 204-214. doi:10.1016/j.agrformet.2010.10.005Næsset, E. (2004). Accuracy of forest inventory using airborne laser scanning: evaluating the first nordic full-scale operational project. Scandinavian Journal of Forest Research, 19(6), 554-557. doi:10.1080/02827580410019544Popescu, S. C. (2007). Estimating biomass of individual pine trees using airborne lidar. Biomass and Bioenergy, 31(9), 646-655. doi:10.1016/j.biombioe.2007.06.022Popescu, S. C., Wynne, R. H., & Nelson, R. F. (2002). Estimating plot-level tree heights with lidar: local filtering with a canopy-height based variable window size. Computers and Electronics in Agriculture, 37(1-3), 71-95. doi:10.1016/s0168-1699(02)00121-7Velázquez-Martí, B., Estornell, J., López-Cortés, I., & Martí-Gavilá, J. (2012). Calculation of biomass volume of citrus trees from an adapted dendrometry. Biosystems Engineering, 112(4), 285-292. doi:10.1016/j.biosystemseng.2012.04.011Velázquez-Martí, B., Fernández-González, E., Estornell, J., & Ruiz, L. A. (2010). Dendrometric and dasometric analysis of the bushy biomass in Mediterranean forests. Forest Ecology and Management, 259(5), 875-882. doi:10.1016/j.foreco.2009.11.027Velázquez-Martí, B., Fernández-González, E., López-Cortés, I., & Salazar-Hernández, D. M. (2011). Quantification of the residual biomass obtained from pruning of trees in Mediterranean olive groves. Biomass and Bioenergy, 35(7), 3208-3217. doi:10.1016/j.biombioe.2011.04.042Yu, X., Hyyppä, J., Kaartinen, H., & Maltamo, M. (2004). Automatic detection of harvested trees and determination of forest growth using airborne laser scanning. Remote Sensing of Environment, 90(4), 451-462. doi:10.1016/j.rse.2004.02.00

Chemical characterization of traditional varietal olive oils in East of Spain

The aim of this work has been to characterize the chemical composition of the eight most emblematic varietal olive oils from the West of the Mediterranean Sea. These were classified into two groups according to the International Olive Council (IOC norms): Sweet oils (Farga, Morruda and Serrana) which were compared with Arbequina as standard of the Spanish sweet oils; and bitter¿spicy oils (Alfafara, Blanqueta, and Villalonga) that were compared with Picual, considered as the standard of the bitter¿spicy olive oils. For the study, sampled trees were chosen in their geographically separated originating areas. They were cultivated in the traditional conditions. The variety of each sampled tree was previously identified by the International Union for the Protection of new Varieties for Plants (UPOV TG/99/4). We have attempted to find differences between these varieties based on their fatty acid and sterol components. Although our results of only the sterols in olive oils suggested that stigmasterol could allow the segregation of the varieties, our experience indicates that analysis of the main fatty acids (palmitic, oleic and linoleic), together with a PCA applied to all fatty acids and sterols, can be used to validate the varietal determinations with enough precision. In addition, α-tocopherol can be used as differentiator in bitter¿spicy oils

Application of Bordeaux mixture for Botrytis control in passion fruit (Passiflora ligularis Juss) cultivated under organic farming in the Andean region

[EN] The aim of this research was the determination of the best conditions for applying Bordeaux mixture for the control of gray mold or rot (Botrytis cinerea) in passion fruit (Passiflora ligularis Juss) grown in organic farming in the Andes. This disease is responsible for nearly 30% loss of production in the province of Tungurahua (Ecuador). To do this, three doses and four frequencies of application in two locations were evaluated. The locations were in the sectors El Galpón and Runtun which are cantons of Patate and Baños, respectively, in Ecuador. Therefore, each experimental unit was composed of 12 blocks (3 doses x 4 frequencies) together a control test with three plants each. In total, 78 plants were evaluated. The doses used were 5 g CuSO4/litre of water (D1), 10 g CuSO4/litre of water (D2), and 15 g CuSO4/litre of water (D3). The studied application frequencies were every 7 days (F1), every 14 days (F2), every 21 days (F3) and every 28 days (F4). From the first application of the treatment, the efficacy was evaluated every 15 days up to 90 days, also performing an economic analysis of the treatments. The evaluation of the effectiveness of each treatment was performed using an affection index, defined as the ratio number of affected organs (branches, leaves, flowers or fruits) and the number of total organs. It has been demonstrated that treatment with 0.5 kg of CuSO4 in 100 litres of water applied every 21 days gives good results for the control of gray mold. Complete removal of the Botrytis was achieved at 75 days after starting treatment. Treatments with higher dose level and the same frequency of application did not improve the results.The participation of Dr. Borja Velázquez Martí in this work was made possible by funding from the Ecuadorian Government by means of PROMETEO program leaded by the Secretaría Nacional de Educación Superior, Ciencia y Tecnología (SENESCYT).Vega, J.; Escobar, B.; Velázquez Martí, B. (2013). Application of Bordeaux mixture for Botrytis control in passion fruit (Passiflora ligularis Juss) cultivated under organic farming in the Andean region. Journal of Food Agriculture and Environment. 11(3 & 4):904-907. http://hdl.handle.net/10251/66297S904907113 &

Wood characterization for energy application proceeding from pruning Morus alba L., Platanus hispanica Münchh. and Sophora japonica L. in urban areas

Pruning urban forests generates significant amounts of lignocellulosic biomass every year. The energy potential of this biomass is unclear. The aim of this research was direct analysis of the gross calorific value (GO!), elemental composition and moisture content of Morus alba L., Platanus hispanica Munchh. and Sophora japonica L by means of laboratory equipment. This analysis allowed for further development of indirect GCV prediction models which are economically attractive and less time consuming to direct analysis. These models presented high coefficients of determination (R-2 0.66-0.96). It has been determined that the species with highest mean GCV is S. japonica L. (19615.68 kJ/kg-dry sample) whereas the one with the lowest is the M. alba L (18192.87 kJ/kg-dry sample). Elemental analysis showed highest carbon (48.22%), hydrogen (6.17%) and nitrogen (1.16%) content in S. japonica L in dry samples. Sulfur was constant at the level 0.05% for all analyzed species. Also percentage of bark and wood density were determined. Mean percentage of bark was highest for P. hispanica Miinchh. (13.05%) while wood density was highest for S. japonica L. (0.86 g cm(-3)). This way the research has proven that the biomass produced by pruning urban forests appears to be an interesting source of renewable energy. (C) 2013 Elsevier Ltd. All rights reserved.Velázquez Martí, B.; Sajdak, M.; López Cortés, I.; Callejón-Ferre, AJ. (2014). Wood characterization for energy application proceeding from pruning Morus alba L., Platanus hispanica Münchh. and Sophora japonica L. in urban areas. Renewable Energy. (62):478-483. doi:10.1016/j.renene.2013.08.010S4784836

Residual biomass calculation from individual tree architecture using terrestrial laser scanner and ground-level measurements

Large quantity of residual biomass with possible energy and industrial end can be obtained from management operations of urban forests. The profitability of exploiting this resource is conditioned by the amount of existing biomass within urban community ecosystems. Prior research pointed out that residual biomass from Platanus hispanica and other tree species can be calculated from dendrometric parameters. In this study, two approaches have been analyzed: First, applicability of TLS was tested for residual biomass calculation from crown volume. In addition, traditional models for residual biomass prediction were developed from dendrometric parameters (tree height, crown diameter, and diameter at breast height). Next, a comparison between parameters obtained with both methodologies (standard methodologies vs TLS) was carried out. The results indicate a strong relationship (R2 = 0.906) between crown diameters and between total tree heights (R2 = 0.868). The crown volumes extracted from the TLS point cloud were calculated by 4 different methods: convex hull; convex hull by slices of 5 cm height in the XY plane; triangulation by XY flat sections, and voxel modeling. The highest accuracy was found when the voxel method was used for pruned biomass prediction (R2 = 0.731). The results revealed the potential of TLS data to determine dendrometric parameters and biomass yielded from pruning quitar of urban forestsFernández-Sarría, A.; Velázquez Martí, B.; Sajdak, M.; Martinez, L.; Estornell Cremades, J. (2013). Residual biomass calculation from individual tree architecture using terrestrial laser scanner and ground-level measurements. Computers and Electronics in Agriculture. 93:90-97. doi:10.1016/j.compag.2013.01.012S90979