Tree Risk Assessment in the College of Forestry and Natural Resources, University of the Philippines Los Baños, Laguna
DOI:
https://doi.org/10.64807/2j4whz46Abstract
Trees are essential components of campus landscapes, providing ecological, aesthetic, and microclimatic benefits; however, when located near infrastructure and areas of high human activity, trees pose potential risks when structural defects are present. This study assessed tree-related risks within 10 meters of the academic buildings at the College of Forestry and Natural Resources, University of the Philippines, Los Baños. The study determined the species composition and structural characteristics of trees, evaluated their risk levels using the International Society of Arboriculture (ISA) Basic Tree Risk Assessment framework supported by sonic tree tomography, and mapped the spatial distribution of tree risks to guide mitigation strategies. A total of 116 trees representing 23 families were inventoried and assessed. The families Meliaceae, Fabaceae, and Moraceae were the most dominant across the study area. Diversity analysis indicated relatively high species diversity (H’ = 3.741) but moderate evenness, indicating the dominance of several species within the landscape. There were 66 trees classified as moderate risk, 27 as low risk, 22 as high risk, and one as extreme risk, with common defects included codominant stems, weak branch attachments, broken branches, hanging limbs, trunk decay, leaning stems, root plate lifting, and root cavities. Statistical analysis revealed weak but significant positive correlations between tree risk level and structural variables, including DBH (rs = 0.270, p = 0.003), TH (rs = 0.212, p = 0.022), and crown spread (rs = 0.264, p = 0.004). Sonic tree tomography of ten selected high-risk trees revealed varying levels of internal decay. Spatial mapping identified clusters of moderate to extreme-risk trees near areas of frequent human activity. Targeted mitigation strategies were proposed, ranging from routine monitoring to immediate interventions, such as tree removal, to enhance campus safety and support sustainable tree management.
Keywords:
tree failure, sonic tree tomography, mitigation, decay, defectsReferences
Aguiar, A.C., French, K., and Chisholm, L.A. (2014). A Comparison of The Ameliorating Effects of Native and Exotic Street Trees on Surface Heat Retention at Dusk. Urban Climate, 10, 56–62. https://doi.org/10.1016/j.uclim.2014.09.004
Allison, R. B., Wang, X., and Senalik, C. A. (2020). Methods for Nondestructive Testing of Urban Trees. Forests, 11(12), 1341. https://doi.org/10.3390/f11121341
Aloi, F., Riolo, M., Parlascino, R., Pane, A., and Santa Olga Cacciola. (2021). Bot Gummosis of Lemon (Citrus × limon) Caused by Neofusicoccum parvum. Journal of Fungi, 7(4), 294–294. https://doi.org/10.3390/jof7040294
American National Standard Institute (ANSI) (2016). A Revision Draft of A300 (Part 1)-2008. For Tree Care Operations (p-16). Tree Care Industry Association. https://cdn.ymaws.com/www.ascaconsultants.org/resource/resmgr/docs/at_work/A300Part1-Pruning-D3V1-PR-Co.pdf
Ata, J. P. (2025). Re-Examining Forest Health Amid Changing Environments: Fungal Diseases in Philippine Forests. Revista Chapingo Serie Ciencias Forestales Y Del Ambiente, 31. https://doi.org/10.5154/r.rchscfa.2024.08.026
Bakewell-Stone, P. (2022). Swietenia macrophylla (big leaved mahogany). CABI Compendium, CABI Compendium. https://doi.org/10.1079/cabicompendium.52155
Bakewell-Stone, P. (2023, December 11). Swietenia macrophylla (big leaved mahogany). CABI Digital Library. https://doi.org/10.1079/cabicompendium.52155
Brazee, N. J., Marra, R. E., Gocke, L., and Van Wassenaer, P. (2011, January). Non-destructive assessment of internal decay in three hardwood species of northeastern North America using sonic and electrical impedance tomography. Forestry, 84(1), 33–39. https://doi.org/10.1093/forestry/cpq040
Cantiani, P., and Chiavetta, U. (2015). Estimating The Mechanical Stability Of Pinus Nigra Arn. Using An Alternative Approach Across Several Plantations In Central Italy. IForest - Biogeosciences and Forestry, 8(6), 846–852. https://doi.org/10.3832/ifor1300-007
Castro-Medina, F., Mohali, S., Úrbez-Torres, J. R., and Gubler, W. D. (2014). First report of Lasiodiplodia pseudotheobromae causing trunk cankers in Acacia mangium in Venezuela. Plant Disease, 98(5), 686. https://doi.org/10.1094/PDIS-02-13-0160-PDN
Clatterbuck, W.K. (2000). Storm-Damaged Residential Trees - Assessment, Care and Prevention. The University of Tennessee Agricultural Extension. https://trace.tennessee.edu/utk_agexfores/70
Cox, D. (2009). Tree Risk Assessment and Hazard Abatement. Tree Solutions. https://www.seattle.gov/documents/Departments/UrbanForestryCommission/2019/2019docs/AdditionalResourcesSlides.pdf
Dahle, G., James, K., Kane, B., Grabosky, J., and Detter, A. (2017). A Review of Factors That Affect the Static Load-Bearing Capacity of Urban Trees. Arboriculture & Urban Forestry, 43(3). https://doi.org/10.48044/jauf.2017.009
Dunster, J., Smiley, E. T., Matheny, N., and Lilly, S. (2013). Tree risk assessment – Manual. International Society of Arboriculture.
Ellison, M. (2005). Quantified Tree Risk Assessment used in the Management of Amenity Trees. Arboriculture & Urban Forestry, 31(2), 57–65. https://doi.org/10.48044/jauf.2005.007
Fransen, B. (2023, July 22). Native Vs Non-Native Trees: All You Need to Know. EcoMatcher.https://www.ecomatcher.com/native-vs-non-native-trees-all-you-need-to-know
Fraver, S., Tajvidi, M., D’Amato, A.W., Lindner, D.L., Forrester, J.A., and Milo, A.M. (2018). Woody material structural degradation through decomposition on the forest floor. Canadian Journal of Forest Research, 48(1), 111–115. https://doi.org/10.1139/cjfr-2017-0175
Gauthier, N., Fountain, W.E., Missun, T. (2015, September). Tree Wounds-Invitations to Wood Decay Fungi. University of Kentucky Extension. https://plantpathology.mgcafe.uky.edu/files/ppfs-or-w-01.pdf
Gilman, E., and Grabosky, J. (2006). Branch Union Morphology Affects Decay Following Pruning. Arboriculture & Urban Forestry, 32(2), 74–79. https://doi.org/10.48044/jauf.2006.010
Gilman, E.F. (2012). An Illustrated Guide to Pruning. Andover Cengage Learning Clifton Park, Ny Delmar. ISBN 13: 978-1-111-30730-1.
Gilman, E.F. (2020). Cavities - Maintenance - Landscape plants. UF/IFAS. https://hort.ifas.ufl.edu/woody/cavity.shtml
Gilman, E.F., Watson, D.G., Klein, R.W., Koeser, A.K., Hilbert, D.R., and McLean, D.C. (2019, March 26). Ficus lyrata: Fiddle leaf. https://edis.ifas.ufl.edu/publication/ST254
Hassan, K., Mohamad, W.S.N.W., Hasan, R., and Alwi, N.M. (2023). Perceptual Differences Of Tree Removal In Development Areas Among Landscape Professionals. Planning Malaysia, 21. https://doi.org/10.21837/pm.v21i29.1363
He, K., Wei, L., and Wang, B. (2024). Construction Of Street Tree Risk Assessment System and Empirical Analysis Based on Non-Destructive Testing Technologies. Frontiers in Earth Science, 12. https://doi.org/10.3389/feart.2024.1338316
Helliwell, R. (2004). A discussion of the failure of weak forks. Arboricultural Journal, 27(3), 245–249. https://doi.org/10.1080/03071375.2004.9747382
Helmanto, H., Damayanti, F., and Rachmadiyanto, A. N. (2022). A safety factor of old trees, Pterocarpus indicus Willd. in Bogor Botanic Gardens. IOP Conference Series: Earth and Environmental Science, 950(1), 012009. https://doi.org/10.1088/1755-1315/950/1/012009
Hernandez, J. O., Maldia, L.S.J., and Park, B. B. (2020). Research Trends and Methodological Approaches of the Impacts of Windstorms on Forests in Tropical, Subtropical, and Temperate Zones: Where Are We Now and How Should Research Move Forward? Plants, 9(12), 1709. https://doi.org/10.3390/plants9121709
Ihsan, F. and Rosleine, D. (2020). Cooling effect to mitigate Urban Heat Island by Pterocarpus indicus, Swietenia macrophylla and Samanea saman In Bandung, West Java Indonesia. IOP Conference Series, 528(1), 012057–012057. https://doi.org/10.1088/1755-1315/528/1/012057
International Society of Arboriculture (2017). Using the ISA basic tree risk assessment form. https://wwv.isaarbor.com/education/resources/ISABasicTreeRiskAssessmentForm_Instructions.pdf
James, K., Dahle, G., Grabosky, J., Kane, B., and Detter, A. (2014). Tree Biomechanics Literature Review: Dynamics. Arboriculture & Urban Forestry, 40(1). https://doi.org/10.48044/jauf.2014.001
Klein, R., Koeser, A., Hauer, R., Hansen, G., and Escobedo, F. (2019). Risk assessment and risk perception of trees: A review of literature relating to arboriculture and urban forestry. Arboriculture & Urban Forestry, 45(1). https://doi.org/10.48044/jauf.2019.003
Konopiński, M.K. (2020). Shannon diversity index: a call to replace the original Shannon’s formula with unbiased estimator in the population genetics studies. PeerJ, 8. https://doi.org/10.7717/peerj.9391
Krisnawati, H., Kallio, M., and Kanninen, M. (2011). Swietenia macrophylla King Ecology, Silviculture and Productivity. https://www.cifor-icraf.org/publications/pdf_files/Books/BKrisnawati1104.pdf
Li, H., Zhang, X., Li, Z., Wen, J., and Tan, X. (2022). A review of research on tree risk assessment methods. Forests, 13, 1556. https://doi.org/10.3390/f13101556
Magcale-Macandog, D. B., Paller, G. V., Cervancia, C. R., Buot, I. E., Torreta, N. K., Amor, I., Manila-Fajardo, A. C., Fajardo, A. C., Marjorie, Marie, H., Alexis, C., Natuel, F. A., & Laruya, J. M. (2023). A Survey of Understory Vegetation in the Biocultural Landscape of Mount Makiling, Luzon Island, Philippines: Implications for Sustainable Management. 301–342. https://doi.org/10.1007/978-981-19-8649-9_15
Magurran, A.E. (2004). Measuring Biological Diversity. Blackwell Publishing. https://doi.org/10.1016/j.cub.2021.07.049
McHugh, M.L. (2013). The Chi-square Test of Independence. Biochemia Medica, 23(2), 143–149. National Library of Medicine. https://doi.org/10.11613/bm.2013.018
Moore, G.M. (2014). Wind-Thrown Trees: Storms or Management? Arboriculture & Urban Forestry, 40(2). https://doi.org/10.48044/jauf.2014.007
Muhammad H., Jiao X., Chunhua Y., Bowen X., Bei W., Longjun Q., Sajjad S., Altaf H., Zhendong Z., and Guo Yu Q. (2021, June 1). Environmental control on transpiration and its cooling effect of Ficus concinna in a subtropical city Shenzhen, southern China, Agricultural and Forest Meteorology. https://doi.org/10.1016/j.agrformet.2021.108715
Mulyani, Y.A, Kusrini, M.D., and Mardiastuti, A. (2021). Diversity of fig trees in a tropical urban residential area of Sentul City, Bogor, West Java. https://iopscience.iop.org/article/10.1088/1755-1315/918/1/012013
Murray, M. (2020). Identifying and Managing Cankers on Landscape Trees. ISA. https://wwv.isa-arbor.com/quizbank/resources/5614/CEU_042020.pdf
Negishi, T., and Kanno, H. (2022). Nondestructive decay diagnosis of war-damaged trees by sonic tomography. Randosukēpu Kenkyū, 85(5), 433–438. https://doi.org/10.5632/jila.85.433
Nelson, A. H., and Hudler, G. W. (2007). A Summary of North American Hardwood Tree Diseases with Bleeding Canker Symptoms. Arboriculture & Urban Forestry, 33(2), 122–131. https://doi.org/10.48044/jauf.2007.013
Noorliyana R., Zulhilmi Z., Hamid, A., Saiful, W., Syahidah A.M, Hasan, R., Nurul I.O, and Muhamad F.R. (2023). Identification of Tropical Planting Selection for Sustainable Campus Design. Bio Web of Conferences/BIO Web of Conferences, 73, 05030–05030. https://doi.org/10.1051/bioconf/20237305030
Ogle, C. (2021). Chapter 11: Structural Defects, Tree Failure, and Risk. The Virginia Cooperative Extension Master Gardener Tree Steward Manual. https://vtechworks.lib.vt.edu/server/api/core/bitstreams/de5adfab-ab6c-4b2c-939f-127af9c18803/content
Pradipta, E., Kholis, N., Lestari, F., and Bowolaksono, A. (2018). Tree risk identification, assessment, and mitigation in Universitas Indonesia’s urban forest. IOP Conference Series: Earth and Environmental Science, 203, 012026. https://doi.org/10.1088/1755-1315/203/1/012026
Purcell, L. (2012). Tree Risk Management. FNR-475-W. https://www.extension.purdue.edu/extmedia/FNR/FNR-475-W.pdf
Rinn, F. (2012). Rinntech Arbotom manual. Rinntech. https://rinntech.info/products/arbotom/
Roloff, A. (2016). Urban tree management: For the sustainable development of green cities. John Wiley & Sons.
Rust, S. (2016). Chapter 9: Tree Inventory, risk assessment and management. Urban Tree Management for Sustainable Development of Green Cities. John Wiley and Sons, Ltd.
Sarmiento, Roger and Mercado, Joel. (2019). Land use changes and their influence in the conservation of plant diversity within a small Binaba watershed. Journal of Biodiversity and Environmental Sciences. 14. 139-150.
Schneider, C., Rasband, W., and Eliceiri, K. (2012, June 28). NIH Image to ImageJ: 25 years of image analysis. Nature Methods, 9, 671–675. https://doi.org/10.1038/nmeth.2089
Shi, F., Meng, Q. L., Pan, L., and Wang, J. (2023). Root damage of street trees in urban environments: An overview of its hazards, causes, and prevention and control measures. Science of The Total Environment, 166728. https://doi.org/10.1016/j.scitotenv.2023.166728
Slik, F., Pinho, B.X., Griffith, D.M., Webb, E., Raghubanshi, A.S., Quaresma, A.C., Hemati, Z. (2024). Wind Dispersed Tree Species Have Greater Maximum Height. Global Ecology and Biogeography, 33(9). https://doi.org/10.1111/geb.13878
Smiley, E. T., Matheny, N. P., and Lilly, S. J. (2017). Tree risk assessment (pp. 478–488). Routledge. https://doi.org/10.4324/9781315627106-31
Smiley, E. T., Matheny, N., and Lilly, S. (2012, February). Tree risk assessment: A foundation. Arborist.https://www.researchgate.net/publication/302508127_Qualitative_Tree_Risk_Assessment
Stone, I. (2023). What To Do About “Hangers” In Your Tree? Gardening in the Panhandle. Ufl.edu. https://nwdistrict.ifas.ufl.edu/hort/2023/07/27/what-to-do-about-hangers-in-your-tree/
Suchocka, M., Wojnowska-Heciak, M., Jankowski, P., Mojski, J., Milanowska, A., Kubus, M., and Kalaji, H. M. (2022). Potential Hazard Characteristics of Trees with Hollows, Cavities and Fruiting Bodies Growing Along Pedestrian Routes. Scientific Reports, 12(1), 21417. https://doi.org/10.1038/s41598-022-25946-0
Sudrajat, D. J., Ayyasy, Y., Siregar, I. Z., and Karlinasari, L. (2021). Mahogany (Swietenia macrophylla King.) as urban tree: tree growth and wood quality variation in a progeny test. IOP Conference Series: Earth and Environmental Science, 918(1), 012042. https://doi.org/10.1088/1755-1315/918/1/012042
Susilowati, A., Rangkuti, A.B., Rachmat, H.H., Iswanto, A.H., Harahap, M.M., Elfiati, D., Slamet, B., and Ginting, I.M. (2021). Maintaining Tree Biodiversity in Urban Communities on The University Campus. Biodiversitas Journal of Biological Diversity, 22(5). https://doi.org/10.13057/biodiv/d220548
Threlfall, C.G., Ossola, A., Hahs, A.K., Williams, N.S.G., Wilson, L., and Livesley, S.J. (2016). Variation in Vegetation Structure and Composition across Urban Green Space Types. Frontiers in Ecology and Evolution, 4. https://doi.org/10.3389/fevo.2016.00066
Till, R. and Prager, T (2025, February 7). Tree Risk Assessment for the Davis-Meeker Oak. https://mccmeetingspublic.blob.core.usgovcloudapi.net/tumwater-meet-fbacb66a36e74fe2b903870fbf28e97d/ITEM-Attachment-001-4ee7b13143b146e5b0e0ce1777db7889.pdf
Tu, Mandy (2021, July 2). Ask an Expert: Fabulous Fabaceae! Hoyt Arboretum Blog. https://www.hoytarboretum.org/ask-an-expert-fabulous-fabaceae/
Watson, G., Hewitt, A., Custic, M., and Lo, M. (2014). The Management of Tree Root Systems in Urban and Suburban Settings II: A Review of Strategies to Mitigate Human Impacts. Arboriculture & Urban Forestry, 40(5). https://doi.org/10.48044/jauf.2014.025
Wilson, J. (2024). Repairing Storm-Damaged Shade, Ornamental, and Fruit Trees Broken and Torn Limbs. Mississippi State University Extension Service. https://extension.msstate.edu/sites/default/files/publications/publications/P3667_web.pdf
Wiseman, P.E., Orton, M., Hamersky, W., Maywalt, T., Little, A., Angle, B., Harris, C., Harold, J., White, B., Johnson, L., O’Liddy, M., McGlone, J., and Downing, A. K. (2020). A Training Manual for Virginia Tree Stewards, 4th Edition. Vt.edu; Virginia Urban Forest Council. https://vtechworks.lib.vt.edu/items/2e870966-1f7f-41bf-990d-05917cbe87b7
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Risha Ann Cortes (Author)
This work is licensed under a Creative Commons Attribution 4.0 International License.
All articles published in QCU Journals are made available under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
This license allows for:
- Sharing – copying and redistributing the material in any medium or format.
- Adapting – remixing, transforming, and building upon the material for any purpose, including commercial use.
