Year 2021,
Volume: 8 Issue: 1, 58 - 80, 29.03.2021
Yusuf Abba Kyari
,
James Agajo
References
- Adegoke, A. S., & Siddle, D. (2012, May). Investigation into vegetation effects on propagating radio waves. Conference on Applied Radio System Research (ARSR-SWICOM), University of Manchester, United Kingdom.
- Al-Basheir, M. S., Shubair, R. M., & Sharif, S. M. (2006). Measurements and analysis for signal attenuation through date palm trees at 2.1 GHz frequency. Sudan Engineering Society Journal, 52(45), 17-22.
- Al-Naimi, M. O., & Hammoudeh, A. M. (1993). Influence of Vegetation on Attenuation of Radio wave Signals in the X-Band Frequency Region. COST 235 TD, CP 149.
- Arzai, A., & Aliyu, B. (2010). The relationship between canopy width, height and trunk size in some tree species growing in the Savana zone of Nigeria. Bayero Journal of Pure and Applied Sciences, 3(1), 260-263. doi:10.4314/bajopas.v3i1.58808
- BBC & ITC (1998). The Effect of Trees on Television Reception. Arboricultural Advisory & Information Service, Arboriculture Research Note: 146/98/TV. (Accessed: 06/07/2015) www.users.globalnet.co.uk/~skellern/download/tv_reception.pdf
- Bragg, D. C. (2001). A local basal area adjustment for crown width prediction. Northern Journal of Applied Forestry, 18(1), 22-28.
- Burgin, M., Clewley, D., Lucas, R. M., & Moghaddam, M. (2011). A Generalized Radar Backscattering Model Based on Wave Theory for Multilayer Multispecies Vegetation. IEEE Transactions on Geoscience and Remote Sensing, 49(12), 4832-4845. doi:10.1109/TGRS.2011.2172949
- Corral-Rivas, S., Álvarez-González, J., Crecente-Campo, F., & Corral-Rivas, J. (2014). Local and generalized height-diameter models with random parameters for mixed, uneven-aged forests in Northwestern Durango, Mexico. Forest Ecosystems, 1(1), 6. doi:10.1186/2197-5620-1-6
- COST (1996). COST 235 – Radiowave propagation effects on next-generation fixed-services terrestrial telecommunications systems. European Commission, Luxembourg. ISBN:92-827-8023-6
- El-Shaarawi, A. H., & Piegorsch, W. W. (2002). Encyclopaedia of Environmetrics. John Wiley & Sons, Ltd. doi:10.1002/9780470057339
- Eloy, C. (2011). Leonardo’s Rule, Self-Similarity, and Wind-Induced Stresses in Trees. Physıcal Review Letters,107(25), 258101. doi:10.1103/PhysRevLett.107.258101
- Eng, H. (2012). Tree Height Estimation in Redwood/Douglas-fir Stands in Mendocino County. In: Proceedings of Coast Redwood Forests in a Changing California: A Symposium for Scientists and Managers (pp. 649-654), Pacific Southwest Research Station, Forest Service, US Department of Agriculture: Albany, CA, USA.
- Ghasemi, A., Abedi, A., & Ghasemi, F. (2013). Propagation Engineering in Radio Links Design. New York, Springer. doi:10.1007/978-1-4614-5314-7
- Ghoraishi, M., Takada, J., & Imai, T., (2013). Radio Wave Propagation Through Vegetation. In: Y. Zheng (Eds.), Wave Propagation Theories and Applications (pp. 155-174). doi:10.5772/52571
- Gilman, E. F. (2003). Branch-to-stem diameter ratio affects strength of attachment. Journal of Arboriculture, 29(5), 291-294.
- Goldhirsh, J., & Vogel, W. J. (1998). Handbook of propagation effects for vehicular and personal mobile satellite systems: overview of experimental and modelling results. Report jointly authored by The Johns Hopkins University Applied Physics Laboratory (APL: A2A-98-U-0-021) and The University of Texas at Austin Electrical Engineering Research Laboratory (EERL: EERL-98-12A).
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- Groot, A., & Schneider, R. (2011). Predicting maximum branch diameter from crown dimensions, stand characteristics and tree species. The Forestry Chronicle, 87(04), 542-551. doi:10.5558/tfc2011-053
- Helhel, S., Özen, Ş., & Göksu, H. (2008). Investigation of GSM signal variation depending weather conditions. Progress In Electromagnetics Research B, 1, 147-157. doi:10.2528/PIERB07101503
- Hemery, G. E., Savill, P. S., & Pryor, S. N. (2005). Applications of the crown diameter-stem diameter relationship for different species of broadleaved trees. Forest Ecology and Management, 215(1-3), 285-294. doi:10.1016/j.foreco.2005.05.016
- Hong, B. (2015). Predicting the Growth in Tree Height for Building Sunshine in Residential District. Open Journal of Forestry, 5(1), 57-65. doi:10.4236/ojf.2015.51007
- Ibrahim, E. M., Osman, E. H. & Idris, E. A. (2014). Modelling the Relationship between Crown width and Diameter at Breast Height for Naturally grown Terminalia tree species. J. Nat. Resour. Environ. Stud., 2(2), 42-49.
- ITU (2013). Attenuation in vegetation. Series of ITU-R Recommendations P.833-8. International Telecommunication Union, Geneva. (Accessed: 23/10/2019) https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.833-8-201309-S!!PDF-E.pdf
- Jessen, R. J. (1955). Determining the Fruit Count on a Tree by Randomized Branch Sampling. Biometrics, 11(1), 99-109. doi:10.2307/3001484
- Kirtley, P. (2013). How To Identify An Ash Tree. (Accessed: 23/10/2019) http://paulkirtley.co.uk/2013/how-to-identify-an-ash-tree/
- Koh, I. S., Wang, F., & Sarabandi, K. (2003). Estimation of coherent field attenuation through dense foliage including multiple scattering. IEEE Transactions on Geoscience and Remote Sensing, 41(5), 1132-1135. doi:10.1109/TGRS.2003.813552
- Lin, Y-C., & Sarabandi, K. (1999). A Monte Carlo coherent scattering model for forest canopies using fractal-generated trees. IEEE Transactions on Geoscience and Remote Sensing, 37(1), 440-451. doi:10.1109/36.739083
- Lockhart, B. R., Weih, R. C., & Smith, K. M. (2005). Crown radius and diameter at breast height relationship for six bottomland hardwood species. Journal of the Arkansas Academy of Science, 59, 110-115.
- Loubère, M., Saint-André, L., Hervé J-C., & Vestøl, G. I. (2004). Relationships between stem size and branch basal diameter variability in Norway spruce (Picea abies (L.) Karsten) from two regions of France. Annals of Forest Science, 61(6), 525-535. doi:10.1051/forest:2004047
- Martínez-Vilalta, J., Vanderklein, D., & Mencuccini, M. (2006). Tree height and age-related decline in growth in Scots pine (Pinus sylvestris L). Oecologia, 150(4), 529-544. doi:10.1007/s00442-006-0552-7
- McLarnon, B. (1997). HF/UHF/Microwave Radio Propagation: A Primer for Digital Experimenters. Proceedings of the American Relay Radio League (ARRL) Conference.
- Meng, Y. S., & Lee, Y. H. (2010). Investigations of foliage effect on modern wireless communication systems: A review. Progress In Electromagnetics Research, 105, 313-332. doi:10.2528/PIER10042605
- Ndzi, D., Savage, N., & Stuart, K. (2005, Oct). Wideband Signal propagation through Vegetation. XVII GA of URSI.
- Ndzi, D. L., Kamarudin, L. M., Mohammad, E. A. A., Zakaria, A., Ahmad, R. B., Fareq, M. M. A., Shakaff, A. Y. M., & Jafaar, M. N. (2012). Vegetation attenuation measurements and modelling in plantations for wireless sensor network planning. Progress In Electromagnetics Research B, 36, 283-301. doi:10.2528/PIERB11091908
- Oyebade, B. A., Popo-ola, F. S., & Alex, A. (2012). Height–Diameter Equations for Eight Midwestern Rainforest Species in Nigeria using Monserud’s Model. ARPN Journal of Science and Technology, 2(5), 480-486.
- Peper, P. J., McPherson, E. G., & Mori, S. M. (2001). Equations for predicting diameter, height, crown width, and leaf area of San Joaquin Valley street trees. Journal of Arboriculture, 27, 306-317.
- Petrauskas, E., & Rupšys, P., (2010) Age-Varying Bivariate Distribution Models for Growth Prediction. In: V. Mladenov, K. Psarris, N. Mastorakis, A. Caballero, & G. Vachtsevanos (Eds.), Mathematical Models for Engineering Science (pp. 250-255). International Conference on Mathematical Models for Engineering Science (MMES '10), November 30-December 2, Puerto De La Cruz, Tenerife, Spain. ISBN: 978-960-474-252-3
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- Rupšys, P., & Petrauskas, E. (2010). The bivariate Gompertz diffusion model for tree diameter and height distribution. Forest Science, 56(3), 271-280.
- Sabri, N., Mohammed, S. S., Fouad, S., Syed, A. A., Al-Dhief, F. T., & Raheemah, A. (2018). Investigation of Empirical Wave Propagation Models in Precision Agriculture. MATEC Web of Conferences, 150, 06020. doi:10.1051/matecconf/201815006020
- Sánchez-González, M., Cañellas, I., & Montero, G. (2007). Generalized height-diameter and crown diameter prediction models for cork oak forests in Spain. Investigación Agraria: Sistemas y Recursos Forestales, 16(1), 76-88.
- Savage, N., Ndzi, D., Seville, A., Vilar, E., & Austin, J. (2003). Radio wave propagation through vegetation: Factors influencing signal attenuation. Radio Science, 38(5), 1088. doi:10.1029/2002RS002758
- Schlecht, R. (2011). Application of Randomized Branch Sampling to Conifer Trees: Estimating Crown Biomass. MSc Thesis, University of Montana.
- Schreuder, H. T., & Hafley, W. L. (1977). A Useful Bivariate Distribution for Describing Stand Structure of Tree Heights and Diameters. Biometrics, 33(3), 471-478. doi:10.2307/2529361
- Seville, A., & Craig, K. H. (1995). Semi-empirical model for millimetre-wave vegetation attenuation rates. Electronics Letters, 31(17), 1507-1508. doi:10.1049/el:19951000
- Shinozaki, K., Yoda, K., Hozumi, K., & Kira, T. (1964). A Quantitative Analysis of Plant Form - The Pipe Model Theory: I. Basic Analyses. Japanese Journal of Ecology, 14(3), 97-105. doi:10.18960/seitai.14.3_97
- Shrestha, R., & Wynne, R. (2012). Estimating Biophysical Parameters of Individual Trees in an Urban Environment Using Small Footprint Discrete-Return Imaging Lidar. Remote Sensing, 4(2), 484-508. doi:10.3390/rs4020484
- Stephens, R. B. L., & Al-Nuaimi, M. O. (1995). Attenuation measurements and modelling in vegetation media at 11.2 and 20 GHz. Electronics Letters, 31(20), 1783-1785. doi:10.1049/el:19951215
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- Vanclay, J. K. (2009). Tree diameter, height and stocking in even-aged forests. Annals of Forest Science, 66(7), 702. doi:10.1051/forest/2009063
- Wang, C-H., & Hann, D. W. (1988). Height-diameter equations for sixteen tree species in the central western Willamette Valley of Oregon. Forest Research Laboratory, Oregon State University, Corvallis. Research Paper: 51.
- Wang, F., & Sarabandi, K. (2005). An enhanced millimeter-wave foliage propagation model. IEEE Transactions on Antennas and Propagation, 53(7), 2138-2145.
- Wang, F., & Sarabandi, K. (2007). A physics-based statistical model for wave propagation through foliage. IEEE Transactions on Antennas and Propagation, 55(3), 958-968. doi:10.1109/TAP.2007.891841
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Wireless Signal Attenuation by Vegetation: Relationship Between Tree Characteristics and Signal Attenuation
Year 2021,
Volume: 8 Issue: 1, 58 - 80, 29.03.2021
Yusuf Abba Kyari
,
James Agajo
Abstract
Vegetation is a significant factor that affects the Quality of Service of radio waves. Several measurement campaigns have been conducted to predict the effect of trees on a radio wave at the micro and millimetre wavelengths. The experiments show that depth of vegetation is a major factor that contribute to signal attenuation. Furthermore, different components of the vegetation cause different behaviours of the radio wave. The empirical models did not put into to consideration the characteristics of the trees in the vegetation. The analytical approaches using wave theory have considered the vegetation characteristics, density and the geometry. This paper focuses on using existing models to characterise a vegetation based on measured parameters of a tree stand with a view to estimating the density of the foliage within a vegetation accurately. The foliage density will be used as the vegetation parameter in the wave theory model. Simulation of the signal attenuation will be conducted based on the density of the vegetation that will be estimated. The tree species selected for simulation are Pinus, Ash and Silver Birch tree species.
References
- Adegoke, A. S., & Siddle, D. (2012, May). Investigation into vegetation effects on propagating radio waves. Conference on Applied Radio System Research (ARSR-SWICOM), University of Manchester, United Kingdom.
- Al-Basheir, M. S., Shubair, R. M., & Sharif, S. M. (2006). Measurements and analysis for signal attenuation through date palm trees at 2.1 GHz frequency. Sudan Engineering Society Journal, 52(45), 17-22.
- Al-Naimi, M. O., & Hammoudeh, A. M. (1993). Influence of Vegetation on Attenuation of Radio wave Signals in the X-Band Frequency Region. COST 235 TD, CP 149.
- Arzai, A., & Aliyu, B. (2010). The relationship between canopy width, height and trunk size in some tree species growing in the Savana zone of Nigeria. Bayero Journal of Pure and Applied Sciences, 3(1), 260-263. doi:10.4314/bajopas.v3i1.58808
- BBC & ITC (1998). The Effect of Trees on Television Reception. Arboricultural Advisory & Information Service, Arboriculture Research Note: 146/98/TV. (Accessed: 06/07/2015) www.users.globalnet.co.uk/~skellern/download/tv_reception.pdf
- Bragg, D. C. (2001). A local basal area adjustment for crown width prediction. Northern Journal of Applied Forestry, 18(1), 22-28.
- Burgin, M., Clewley, D., Lucas, R. M., & Moghaddam, M. (2011). A Generalized Radar Backscattering Model Based on Wave Theory for Multilayer Multispecies Vegetation. IEEE Transactions on Geoscience and Remote Sensing, 49(12), 4832-4845. doi:10.1109/TGRS.2011.2172949
- Corral-Rivas, S., Álvarez-González, J., Crecente-Campo, F., & Corral-Rivas, J. (2014). Local and generalized height-diameter models with random parameters for mixed, uneven-aged forests in Northwestern Durango, Mexico. Forest Ecosystems, 1(1), 6. doi:10.1186/2197-5620-1-6
- COST (1996). COST 235 – Radiowave propagation effects on next-generation fixed-services terrestrial telecommunications systems. European Commission, Luxembourg. ISBN:92-827-8023-6
- El-Shaarawi, A. H., & Piegorsch, W. W. (2002). Encyclopaedia of Environmetrics. John Wiley & Sons, Ltd. doi:10.1002/9780470057339
- Eloy, C. (2011). Leonardo’s Rule, Self-Similarity, and Wind-Induced Stresses in Trees. Physıcal Review Letters,107(25), 258101. doi:10.1103/PhysRevLett.107.258101
- Eng, H. (2012). Tree Height Estimation in Redwood/Douglas-fir Stands in Mendocino County. In: Proceedings of Coast Redwood Forests in a Changing California: A Symposium for Scientists and Managers (pp. 649-654), Pacific Southwest Research Station, Forest Service, US Department of Agriculture: Albany, CA, USA.
- Ghasemi, A., Abedi, A., & Ghasemi, F. (2013). Propagation Engineering in Radio Links Design. New York, Springer. doi:10.1007/978-1-4614-5314-7
- Ghoraishi, M., Takada, J., & Imai, T., (2013). Radio Wave Propagation Through Vegetation. In: Y. Zheng (Eds.), Wave Propagation Theories and Applications (pp. 155-174). doi:10.5772/52571
- Gilman, E. F. (2003). Branch-to-stem diameter ratio affects strength of attachment. Journal of Arboriculture, 29(5), 291-294.
- Goldhirsh, J., & Vogel, W. J. (1998). Handbook of propagation effects for vehicular and personal mobile satellite systems: overview of experimental and modelling results. Report jointly authored by The Johns Hopkins University Applied Physics Laboratory (APL: A2A-98-U-0-021) and The University of Texas at Austin Electrical Engineering Research Laboratory (EERL: EERL-98-12A).
- Gregoire, T. G., Valentine, H. T., & Furnival, G. M. (1995). Sampling Methods to Estimate Foliage and Other Characteristics of Individual Trees. Ecological Society of America, 76(4), 1181-1194. doi:10.2307/1940925
- Groot, A., & Schneider, R. (2011). Predicting maximum branch diameter from crown dimensions, stand characteristics and tree species. The Forestry Chronicle, 87(04), 542-551. doi:10.5558/tfc2011-053
- Helhel, S., Özen, Ş., & Göksu, H. (2008). Investigation of GSM signal variation depending weather conditions. Progress In Electromagnetics Research B, 1, 147-157. doi:10.2528/PIERB07101503
- Hemery, G. E., Savill, P. S., & Pryor, S. N. (2005). Applications of the crown diameter-stem diameter relationship for different species of broadleaved trees. Forest Ecology and Management, 215(1-3), 285-294. doi:10.1016/j.foreco.2005.05.016
- Hong, B. (2015). Predicting the Growth in Tree Height for Building Sunshine in Residential District. Open Journal of Forestry, 5(1), 57-65. doi:10.4236/ojf.2015.51007
- Ibrahim, E. M., Osman, E. H. & Idris, E. A. (2014). Modelling the Relationship between Crown width and Diameter at Breast Height for Naturally grown Terminalia tree species. J. Nat. Resour. Environ. Stud., 2(2), 42-49.
- ITU (2013). Attenuation in vegetation. Series of ITU-R Recommendations P.833-8. International Telecommunication Union, Geneva. (Accessed: 23/10/2019) https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.833-8-201309-S!!PDF-E.pdf
- Jessen, R. J. (1955). Determining the Fruit Count on a Tree by Randomized Branch Sampling. Biometrics, 11(1), 99-109. doi:10.2307/3001484
- Kirtley, P. (2013). How To Identify An Ash Tree. (Accessed: 23/10/2019) http://paulkirtley.co.uk/2013/how-to-identify-an-ash-tree/
- Koh, I. S., Wang, F., & Sarabandi, K. (2003). Estimation of coherent field attenuation through dense foliage including multiple scattering. IEEE Transactions on Geoscience and Remote Sensing, 41(5), 1132-1135. doi:10.1109/TGRS.2003.813552
- Lin, Y-C., & Sarabandi, K. (1999). A Monte Carlo coherent scattering model for forest canopies using fractal-generated trees. IEEE Transactions on Geoscience and Remote Sensing, 37(1), 440-451. doi:10.1109/36.739083
- Lockhart, B. R., Weih, R. C., & Smith, K. M. (2005). Crown radius and diameter at breast height relationship for six bottomland hardwood species. Journal of the Arkansas Academy of Science, 59, 110-115.
- Loubère, M., Saint-André, L., Hervé J-C., & Vestøl, G. I. (2004). Relationships between stem size and branch basal diameter variability in Norway spruce (Picea abies (L.) Karsten) from two regions of France. Annals of Forest Science, 61(6), 525-535. doi:10.1051/forest:2004047
- Martínez-Vilalta, J., Vanderklein, D., & Mencuccini, M. (2006). Tree height and age-related decline in growth in Scots pine (Pinus sylvestris L). Oecologia, 150(4), 529-544. doi:10.1007/s00442-006-0552-7
- McLarnon, B. (1997). HF/UHF/Microwave Radio Propagation: A Primer for Digital Experimenters. Proceedings of the American Relay Radio League (ARRL) Conference.
- Meng, Y. S., & Lee, Y. H. (2010). Investigations of foliage effect on modern wireless communication systems: A review. Progress In Electromagnetics Research, 105, 313-332. doi:10.2528/PIER10042605
- Ndzi, D., Savage, N., & Stuart, K. (2005, Oct). Wideband Signal propagation through Vegetation. XVII GA of URSI.
- Ndzi, D. L., Kamarudin, L. M., Mohammad, E. A. A., Zakaria, A., Ahmad, R. B., Fareq, M. M. A., Shakaff, A. Y. M., & Jafaar, M. N. (2012). Vegetation attenuation measurements and modelling in plantations for wireless sensor network planning. Progress In Electromagnetics Research B, 36, 283-301. doi:10.2528/PIERB11091908
- Oyebade, B. A., Popo-ola, F. S., & Alex, A. (2012). Height–Diameter Equations for Eight Midwestern Rainforest Species in Nigeria using Monserud’s Model. ARPN Journal of Science and Technology, 2(5), 480-486.
- Peper, P. J., McPherson, E. G., & Mori, S. M. (2001). Equations for predicting diameter, height, crown width, and leaf area of San Joaquin Valley street trees. Journal of Arboriculture, 27, 306-317.
- Petrauskas, E., & Rupšys, P., (2010) Age-Varying Bivariate Distribution Models for Growth Prediction. In: V. Mladenov, K. Psarris, N. Mastorakis, A. Caballero, & G. Vachtsevanos (Eds.), Mathematical Models for Engineering Science (pp. 250-255). International Conference on Mathematical Models for Engineering Science (MMES '10), November 30-December 2, Puerto De La Cruz, Tenerife, Spain. ISBN: 978-960-474-252-3
- Rogers, N. C., Seville, A., Richter, J., Ndzi, D., Savage, N., Caldeirinha, R. F. S., Shukla, A. K., Al-Nuaimi, M. O., Craig, K., Vilar, E., & Austin, J. (2002). A generic model of 1-60 GHz radio propagation through vegetation-Final report (QinetiQ Report No: QINETIQ/KI/COM/CR020196/1.0), UK Radiocommunications Agency (Contract Number: AY3880/510005719).
- Rupšys, P., & Petrauskas, E. (2010). The bivariate Gompertz diffusion model for tree diameter and height distribution. Forest Science, 56(3), 271-280.
- Sabri, N., Mohammed, S. S., Fouad, S., Syed, A. A., Al-Dhief, F. T., & Raheemah, A. (2018). Investigation of Empirical Wave Propagation Models in Precision Agriculture. MATEC Web of Conferences, 150, 06020. doi:10.1051/matecconf/201815006020
- Sánchez-González, M., Cañellas, I., & Montero, G. (2007). Generalized height-diameter and crown diameter prediction models for cork oak forests in Spain. Investigación Agraria: Sistemas y Recursos Forestales, 16(1), 76-88.
- Savage, N., Ndzi, D., Seville, A., Vilar, E., & Austin, J. (2003). Radio wave propagation through vegetation: Factors influencing signal attenuation. Radio Science, 38(5), 1088. doi:10.1029/2002RS002758
- Schlecht, R. (2011). Application of Randomized Branch Sampling to Conifer Trees: Estimating Crown Biomass. MSc Thesis, University of Montana.
- Schreuder, H. T., & Hafley, W. L. (1977). A Useful Bivariate Distribution for Describing Stand Structure of Tree Heights and Diameters. Biometrics, 33(3), 471-478. doi:10.2307/2529361
- Seville, A., & Craig, K. H. (1995). Semi-empirical model for millimetre-wave vegetation attenuation rates. Electronics Letters, 31(17), 1507-1508. doi:10.1049/el:19951000
- Shinozaki, K., Yoda, K., Hozumi, K., & Kira, T. (1964). A Quantitative Analysis of Plant Form - The Pipe Model Theory: I. Basic Analyses. Japanese Journal of Ecology, 14(3), 97-105. doi:10.18960/seitai.14.3_97
- Shrestha, R., & Wynne, R. (2012). Estimating Biophysical Parameters of Individual Trees in an Urban Environment Using Small Footprint Discrete-Return Imaging Lidar. Remote Sensing, 4(2), 484-508. doi:10.3390/rs4020484
- Stephens, R. B. L., & Al-Nuaimi, M. O. (1995). Attenuation measurements and modelling in vegetation media at 11.2 and 20 GHz. Electronics Letters, 31(20), 1783-1785. doi:10.1049/el:19951215
- Strickland, R. K., & Goddard, R. E. (1965). Inheritance of branching and crown characteristics in slash pine. Proceedings of the 8th Southern Conference on Forest Tree Improvement (pp. 57-63), Savannah, Georgia. June 16-17.
- Sumida, A., Miyaura, T., & Torii, H. (2013). Relationships of tree height and diameter at breast height revisited: analyses of stem growth using 20-year data of an even-aged Chamaecyparis obtusa stand. Tree Physiology, 33(1), 106-118. doi:10.1093/treephys/tps127
- Vanclay, J. K. (1994). Modelling forest growth and yield: applications to mixed tropical forests. CAB International, Wallingford, UK. ISBN: 0-85198-913-6
- Vanclay, J. K. (2009). Tree diameter, height and stocking in even-aged forests. Annals of Forest Science, 66(7), 702. doi:10.1051/forest/2009063
- Wang, C-H., & Hann, D. W. (1988). Height-diameter equations for sixteen tree species in the central western Willamette Valley of Oregon. Forest Research Laboratory, Oregon State University, Corvallis. Research Paper: 51.
- Wang, F., & Sarabandi, K. (2005). An enhanced millimeter-wave foliage propagation model. IEEE Transactions on Antennas and Propagation, 53(7), 2138-2145.
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