Abstract
Through the analysis of an urban tree inventory with the aid of machine learning, this study brought together different aspects of urban forestry. Urban tree monitoring is essential to successful urban forestry. Transport land use accommodates huge tree stock which requires substantial monitoring efforts. In Hong Kong, more research is needed to take into consideration how monitoring works can be improved in response to variations in tree stand characteristics. This case study aimed to illustrate the usefulness of a large-scale tree survey in mainstreaming future tree monitoring and management in transport land use. A total of 7209 trees were found in a large-scale tree survey conducted in 53 slopes and 52 verges along San Tin Highway in Hong Kong. Dominance by Corymbia citriodora (72%) was observed, especially for the highway verges. Using chi-square tests, significant associations were found between monospecific stands, habitat type, and tree risk rating. A logistic regression model was constructed to predict the occurrence of monoculture. Every metre increase in maximum tree height, the odds of a stand being monospecific would be 1.22 times greater. Stands on verges had 5.26 times greater odds of being monospecific against the slope. The associations and relationships were attributed to the dominance of C. citriodora. By boosting the logistic model, model reliability increased as kappa rose from 0.51 to 0.63, while balanced accuracy improved from 0.72 to 0.85. The occurrence of monospecific stands could be reliably predicted using maximum tree height and habitat type of tree stands. These quantitative findings monitoring can guide urban forest monitoring. Through a better understanding of urban forest structure and composition, future monitoring can aid the mainstreaming of urban forestry in transport planning.
Similar content being viewed by others
Data availability
The data that support the findings of this study are available from the Highways Department of the Hong Kong Special Administrative Region Government but restrictions apply to the availability of these data, which were used under licence for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of the Highways Department of the Hong Kong Special Administrative Region Government.
References
American National Standard. (2017). Tree, shrub, and other woody plant management Part 9, tree risk assessment a. Tree failure. American National Standards Institute. ANSI A300.9:2017.
Bandara, W. A. R. T. W., & Dissanayake, C. T. M. (2021). Most tolerant roadside tree species for urban settings in humid tropics based on air pollution tolerance index. Urban Climate, 37, 100848. https://doi.org/10.1016/j.uclim.2021.100848
Booze-Daniels, J. N., Daniels, W. L., Schmidt, R. E., Krouse, J. M., & Wright, D. L. (2000). Establishment of low maintenance vegetation in highway corridors. Reclamation of Drastically Disturbed Lands, 41, 887–920. https://doi.org/10.2134/agronmonogr41.c35
Bucsuházy, K., Zůvala, R., Valentová, V., & Ambros, J. (2022). Factors related to severe single-vehicle tree crashes: In-depth crash study. PLoS ONE, 17(1), e0248171. https://doi.org/10.1371/journal.pone.0248171
Casanelles-Abella, J., Chauvier, Y., Zellweger, F., Villiger, P., Frey, D., Ginzler, C., Moretti, M., & Pellissier, L. (2021). Applying predictive models to study the ecological properties of urban ecosystems: A case study in Zürich. Switzerland. Landscape and Urban Planning, 214, 104137. https://doi.org/10.1016/j.landurbplan.2021.104137
Divakara, B. N., Nikhitha, C. U., Mahmud, M. A., Nölke, N., & Tewari, V. P. (2021). Tree species diversity in the southern transect across the rural-urban interface of Bengaluru. In E. Hoffmann, A. Buerkert, S. von Cramon-Taubadel, K. B. Umesh, P. P. Shivaraj, & P. J. Vazhacharickal (Ed.), The rural-urban interface (pp. 151-162). Springer. https://doi.org/10.1007/978-3-030-79972-4_16
Dunster, J. A., Smiley, E. T., Matheny, N., & Lilly, S. (2017). Tree risk assessment manual (2nd ed.). International Society of Arboriculture.
Fassnacht, F. E., Hartig, F., Latifi, H., Berger, C., Hernández, J., Corvalán, P., & Koch, B. (2014). Importance of sample size, data type and prediction method for remote sensing-based estimations of aboveground forest biomass. Remote Sensing of Environment, 154, 102–114. https://doi.org/10.1016/j.rse.2014.07.028
Felton, A., Nilsson, U., Sonesson, J., Felton, A. M., Roberge, J. M., Ranius, T., Ahlström, M., Bergh, J., Björkman, C., Boberg, J., Drössler, L., Fahlvik, N., Gong, P., Holmström, E., Keskitalo, E. C. H., Klapwijk, M. J., Laudon, H., Lundmark, T., Niklasson, M., … Wallertz, K. (2016). Replacing monocultures with mixed-species stands: Ecosystem service implications of two production forest alternatives in Sweden. Ambio, 45(2), 124–139. https://doi.org/10.1007/s13280-015-0749-2
Hakkenberg, C. R., Song, C., Peet, R. K., & White, P. S. (2016). Forest structure as a predictor of tree species diversity in the North Carolina Piedmont. Journal of Vegetation Science, 27(6), 1151–1163. https://doi.org/10.1111/jvs.12451
Hale, D. C., & Morzillo, A. T. (2020). Landscape characteristics and social factors influencing attitudes toward roadside vegetation management. Landscape Ecology, 35(9), 2029–2044. https://doi.org/10.1007/s10980-020-01078-6
Harris, R. W., Clark, J. R., & Matheny, N. P. (2004). Arboriculture: Integrated management of landscape trees, shrubs, and vines (4th ed.). Prentice Hall.
HKSARG Census and Statistic Department. (2022). Population estimates. Retrieved April 8, 2022, from https://www.censtatd.gov.hk/en/scode150.html
HKSARG Development Bureau. (2012). Allocation of space for quality greening on roads. HKSARG Development Bureau. TC(W) No.2/2012.
HKSARG Development Bureau. (2018). Soft landscape provisions for highway structures. HKSARG Development Bureau. TC(W) No.1/2018.
HKSARG Highways Department. (2022). Road network. Retrieved April 8, 2022, from https://www.hyd.gov.hk/en/road_and_railway/road_network
HKSARG Planning Department. (2021). Land utilization in Hong Kong. Retrieved April 8, 2022, from https://www.pland.gov.hk/pland_en/info_serv/statistic
HKSARG Transport Department. (2020). Road users’ code. HKSARG Transport Department.
Hong Kong Herbarium. (2012). Check list of Hong Kong plants. HKSARG Agriculture, Fisheries and Conservation Department.
Hong Kong Herbarium & South China Botanical Garden. (2007). Flora of Hong Kong, Volume 1. HKSARG Agriculture, Fisheries and Conservation Department.
Hong Kong Herbarium & South China Botanical Garden. (2008). Flora of Hong Kong, Volume 2. HKSARG Agriculture, Fisheries and Conservation Department.
Hong Kong Herbarium & South China Botanical Garden. (2009). Flora of Hong Kong, Volume 3. HKSARG Agriculture, Fisheries and Conservation Department.
Hong Kong Herbarium & South China Botanical Garden. (2011). Flora of Hong Kong, Volume 4. HKSARG Agriculture, Fisheries and Conservation Department.
Huang, X., Teng, M., Zhou, Z., Wang, P., Dian, Y., & Wu, C. (2021). Linking naturalness and quality improvement of monoculture plantations in urban area: A case study in Wuhan city, China. Urban Forestry & Urban Greening, 59, 126911. https://doi.org/10.1016/j.ufug.2020.126911
Jim, C. Y. (1989). The distribution and configuration of tree cover in urban Hong Kong. GeoJournal, 18(2), 175–188.
Jim, C. Y. (1990)Hong Kong University Press. Trees in Hong Kong: Species for landscape planting.
Jim, C. Y. (2008). Multipurpose census methodology to assess urban forest structure in Hong Kong. Arboriculture and Urban Forestry, 34(6), 366–378. https://doi.org/10.1007/BF01207091
Juchheim, J., Ehbrecht, M., Schall, P., Ammer, C., & Seidel, D. (2020). Effect of tree species mixing on stand structural complexity. Forestry: An International Journal of Forest Research, 93(1), 75–83. https://doi.org/10.1093/forestry/cpz046
Kaighn, R. J., Jr., & Yu, S. L. (1996). Testing of roadside vegetation for highway runoff pollutant removal. Transportation Research Record, 1523(1), 116–123. https://doi.org/10.1177/0361198196152300114
Kassambara, A. (2020). ggpubr: ‘ggplot2’ based publication ready plots (Version 0.4–0) [Computer software]. CRAN. https://CRAN.R-project.org/package=ggpubr
Kendal, D., Dobbs, C., & Lohr, V. I. (2014). Global patterns of diversity in the urban forest: Is there evidence to support the 10/20/30 rule? Urban Forestry & Urban Greening, 13(3), 411–417. https://doi.org/10.1016/j.ufug.2014.04.004
Kuhn, M. (2008). Building predictive models in R using the caret package. Journal of Statistical Software, 28, 1–26. https://doi.org/10.18637/jss.v028.i05
Kuhn, M. (2016). caret: Classification and regression training (Version 6.0–71) [Computer software]. CRAN. https://CRAN.R-project.org/package=caret
Lee, L. S. (2022). Quantitative tools for the prediction of pavement damages associated with urban trees. Arboriculture & Urban Forestry, 48(4), 217–232. https://doi.org/10.48044/jauf.2022.016
Lee, L. S., Jim, C. Y., & Zhang, H. (2019). Tree density and diversity in Hong Kong’s public housing estates: From provision injustice to socio-ecological inclusiveness. Urban Forestry & Urban Greening, 46, 126468. https://doi.org/10.1016/j.ufug.2019.126468
Lee, L. S., Zhang, H., & Jim, C. Y. (2021). Serviceable tree volume: An alternative tool to assess ecosystem services provided by ornamental trees in urban forests. Urban Forestry & Urban Greening, 59, 127003. https://doi.org/10.1016/j.ufug.2021.127003
Liu, J., & Slik, F. (2022). Are street trees friendly to biodiversity. Landscape and Urban Planning, 218, 104304. https://doi.org/10.1016/j.landurbplan.2021.104304
Lugo-Pérez, J., & Sabat-Guérnica, A. M. (2011). Structure and composition of woody plants in urban forest remnants with different adjacent land-use and slope aspect. Urban Ecosystems, 14(1), 45–58. https://doi.org/10.1007/s11252-010-0139-2
Ma, B., Hauer, R. J., Wei, H., Koeser, A. K., Peterson, W., Simons, K., Timilsina, N., Werner, L. P., & Xu, C. (2020). An assessment of street tree diversity: Findings and implications in the United States. Urban Forestry & Urban Greening, 56, 126826. https://doi.org/10.1016/j.ufug.2020.126826
Marshall, A. J., Grose, M. J., & Williams, N. S. (2019). From little things: More than a third of public green space is road verge. Urban Forestry & Urban Greening, 44, 126423. https://doi.org/10.1016/j.ufug.2019.126423
Marshall, W. E. P. E., Coppola, N., & Golombek, Y. (2018). Urban clear zones, street trees, and road safety. Research in Transportation Business & Management, 29, 136–143. https://doi.org/10.1016/j.rtbm.2018.09.003
Modlingerová, V., Száková, J., Sysalová, J., & Tlustoš, P. (2012). The effect of intensive traffic on soil and vegetation risk element contents as affected by the distance from a highway. Plant, Soil and Environment, 58(8), 379–384.
Mu, Y., Lin, W., Diao, X., Zhang, Z., Wang, J., Lu, Z., Guo, W., Wang, Y., Hu, C., & Zhao, C. (2022). Implementation of the visual aesthetic quality of slope forest autumn color change into the configuration of tree species. Scientific Reports, 12(1), 1–19. https://doi.org/10.1038/s41598-021-04317-1
Mutlu, S. S., Selim, C., & Gülçin, Ü. N. (2017). Plant biodiversity of urban roadside trees in Antalya, Turkey. Kastamonu University Journal of Forestry Faculty, 17(1), 80–87. https://doi.org/10.17475/kastorman.296501
O’farrell, P. J., & Milton, S. J. (2006). Road verge and rangeland plant communities in the southern Karoo: Exploring what influences diversity, dominance and cover. Biodiversity & Conservation, 15(3), 921–938. https://doi.org/10.1007/s10531-004-3102-9
O’Sullivan, O. S., Holt, A. R., Warren, P. H., & Evans, K. L. (2017). Optimising UK urban road verge contributions to biodiversity and ecosystem services with cost-effective management. Journal of Environmental Management, 191, 162–171. https://doi.org/10.1016/j.jenvman.2016.12.062
Orlóci, L., & Stanek, W. (1980). Vegetation survey of the Alaska Highway, Yukon Territory: Types and gradients. Vegetatio, 41(1), 1–56. https://doi.org/10.1007/BF00055301
Pommerening, A., & Uria-Diez, J. (2017). Do large forest trees tend towards high species mingling? Ecological Informatics, 42, 139–147. https://doi.org/10.1016/j.ecoinf.2017.10.009
Pretzsch, H., Biber, P., Uhl, E., Dahlhausen, J., Rötzer, T., Caldentey, J., Koike, T., van Con, T., Chavanne, A., Seifert, T., du Toit, B., Farnden, C., & Pauleit, S. (2015). Crown size and growing space requirement of common tree species in urban centres, parks, and forests. Urban Forestry & Urban Greening, 14(3), 466–479. https://doi.org/10.1016/j.ufug.2015.04.006
RStudio Team. (2019). RStudio: Integrated Development for R. [Computer software] RStudio, Inc. http://www.rstudio.com
Shataee, S., Kalbi, S., Fallah, A., & Pelz, D. (2012). Forest attribute imputation using machine-learning methods and ASTER data: Comparison of k-NN, SVR and random forest regression algorithms. International Journal of Remote Sensing, 33(19), 6254–6280. https://doi.org/10.1080/01431161.2012.682661
Smiley, E. T., Matheny, N., & Lilly, S. (2011). Best management practices: Tree risk assessment. International Society of Arboriculture.
Soga, M., Yamaura, Y., Koike, S., & Gaston, K. J. (2014). Land sharing vs. land sparing: Does the compact city reconcile urban development and biodiversity conservation?. Journal of Applied Ecology, 51(5), 1378–1386. https://doi.org/10.1111/1365-2664.12280
Song, H., Jeon, G., Lee, S., Kim, N., Park, G., & Lee, B. (2005). Vegetation structure and succession of highway cutting-slope area. Journal of the Korean Society of Environmental Restoration Technology, 8(6), 69–79.
Torgo, L. (2010). Data mining using R: Learning with case studies. CRC Press.
Tuszynski, J. (2021). caTools: Moving window statistics, GIF, Base64, ROC, AUC, etc (Version 1.18.2) [Computer software]. CRAN. https://CRAN.R-project.org/package=caret
Volin, E., Ellis, A., Hirabayashi, S., Maco, S., Nowak, D. J., Parent, J., & Fahey, R. T. (2020). Assessing macro-scale patterns in urban tree canopy and inequality. Urban Forestry & Urban Greening, 55, 126818. https://doi.org/10.1016/j.ufug.2020.126818
Wickham, H., Averick, M., Bryan, J., Chang, W., McGowan, L. D. A., François, R., Grolemund, A. H., Henry, L., Hester, J., Kuhn, M., Pedersen, T. L., Miller, E., Bache, S. M., Müller, K., Ooms, J., Robinson, D., Seidel, D. P., Spinu, V., Takahashi, K., Vaughan, D., Wilke, C., Woo, K., & Yutani, H. (2019). Welcome to the Tidyverse. Journal of Open Source Software, 4(43):1686. https://doi.org/10.21105/joss.01686
Wolf, K. L. (2006). Assessing public response to freeway roadsides: Urban forestry and context-Sensitive solutions. Transportation Research Record, 1984(1), 102–111. https://doi.org/10.1177/0361198106198400110
Yang, J., Luo, X., Lu, S., Yang, Y., & Yang, J. (2022). Effects of compositional and configurational heterogeneity of the urban matrix on the species richness of woody plants in urban remnant forest patches. Landscape Ecology, 37(2), 619–632. https://doi.org/10.1007/s10980-021-01368-7
Yang, J., Yang, J., Xing, D., Luo, X., Lu, S., Huang, C., & Hahs, A. K. (2021). Impacts of the remnant sizes, forest types, and landscape patterns of surrounding areas on woody plant diversity of urban remnant forest patches. Urban Ecosystems, 24(2), 345–354. https://doi.org/10.1007/s11252-020-01040-z
Zeng, S. L., Zhang, T. T., Gao, Y., Ouyang, Z. T., Chen, J. K., Li, B., & Zhao, B. (2011). Effects of road age and distance on plant biodiversity: A case study in the Yellow River Delta of China. Plant Ecology, 212(7), 1213–1229. https://doi.org/10.1007/s11258-011-9899-x
Zheng, J., Zang, H., Yin, S., Sun, N., Zhu, P., Han, Y., Kang, H., & Liu, C. (2018). Modeling height-diameter relationship for artificial monoculture Metasequoia glyptostroboides in sub-tropic coastal megacity Shanghai, China. Urban Forestry & Urban Greening, 34, 226–232. https://doi.org/10.1016/j.ufug.2018.06.006
Źróbek-Sokolnik, A., Dynowski, P., & Źróbek, S. (2021). Preservation and restoration of roadside tree alleys in line with sustainable development principles—mission (Im) possible? Sustainability, 13(17), 9635. https://doi.org/10.3390/su13179635
Funding
This study was funded by the Highways Department of the Hong Kong Special Administrative Region Government.
Author information
Authors and Affiliations
Contributions
All authors contributed to the study conception and design. Data analysis was performed by the first author. The manuscript was written by the first author and all authors commented on, read, and approved the manuscript. We would like to express our gratitude to Gabriella Leung and Marcus Leung for their efforts in data collection.
Corresponding author
Ethics declarations
Competing interests
The third, fourth, and fifth authors were employed by the Highways Department of the Hong Kong Special Administrative Region Government, which funded this research.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Lee, L.S.H., Zhang, H., Ng, K.T.K. et al. Streamlining urban forest monitoring based on a large-scale tree survey: a case study of highway vegetation in Hong Kong. Environ Monit Assess 195, 198 (2023). https://doi.org/10.1007/s10661-022-10803-4
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10661-022-10803-4