Document Type : Original Article


1 Department of Forest Science and Engineering, Faculty of Forest Science, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran

2 Technical Deputy, Department of Forestry and Afforestation, Alborz Natural Resources Office, Karaj, Iran


Considering the importance of forest roads and their positive and negative effects on the forest ecosystem, in this study, the effects of a forest road on species diversity indices related to trees and shrubs in forests of Pasargad city were investigated.
Material and methods:
After field surveys, 30 plots of 400 square meters (20×20 m) were placed on both sides of the road perpendicular along the third-grade forest road with a distance of 100 meters in 0 to 20, 40 to 60 and 80 to 100 m intervals and the species of trees and shrubs were investigated. Then, richness and uniformity indices were calculated and the mean of each index was measured at similar intervals. Then, in SPSS software, the data were normalized by the Kolmogorov-Smirnov test as well as homogeneity analysis of variance using Leven's test. The effect of distance from the road on diversity, richness, and uniformity was determined using a one-way ANOVA method, and Duncan's test was also used to compare the multiple means.
Results and discussion:
The results of the census of the trees in the study area showed that Amygdalus lycioides species had the highest and Ephedra foliate species had the least abundance in the plots. According to the results, the mean values of diversity, richness, and uniformity indices at different distances from the road showed no significant difference. Also, analysis of variance for values of diversity, richness, and evenness indices at specified intervals showed that there was no significant difference in the 95% confidence level between the values of these indices at different distances from the road.
Light competition is one of the factors affecting the establishment of trees and shrubs. There was no light competition in the study area due to the long distances between trees and, therefore, the presence of roads in these conditions wouldn’t affect the light competition. On the other hand, the results showed that with increasing distance from the road, there were no significant differences between the density of trees and shrubs and species diversity indices. Third-grade forest roads are used during limited seasons of the year due to limited infrastructure and pavement, and so the adverse effects of human presence would be limited. Therefore, increasing the distance from third-grade forest road in the study area did not affect the richness, diversity, and evenness of tree and shrubs species.


  1. Azizi, N., GhorbaniNahooji, M., Arman, M. and Sargazi, F., 2014. Biodiversity study of Bonab forest reservoirs in Arsanjan (Fars province). Biological Protection of Plants. 2(5),1-16. (In Persian with English abstract).
  2. Baziari, M., Jalilvand, H., Kooch, Y. and Hosseini, S.A.A., 2011. Ecological effects of forest roads on biodiversity and herbal composition (Case study: Lireh-Sare forestry Plan, Glendrood and Makarood). Journal of Plant Research. 27(1), 41-51. (In Persian with English abstract).
  3. BerenjiTehrani, F., Majnoonian, B., Abdi, A. and ZahediAmiri, Gh.A., 2014. Effects of forest roads on Plant, material, and organic carbon diversity (case study: Kheyrood forest of Noshahr). Forest Sustainability Development Journal. 1(1), 29-43. (In Persian with English abstract).
  4. Bhatt, D. and Sanjit, L., 2005. How relevant are the concepts of species diversity and species richness.
  5. Bioscience. 30(5), 101-104.
  6. Deljooii, A., Abdi, A., Hasanvand, M., Sadeghi, S.M.M. and Keybandi, S., 2016. Impact area of forest roads on flora, biological formation and geographic distribution of plants. Journal of Forest Research and Development. 3(1), 77-89. (In Persian with English abstract).
  7. FakhrAbadi, S., Jafarian, Z., Heidari, Gh.A. and Ghalichnia, H., 2015. Study of variability and species richness indices in different ways of rangeland management (case study: Pleur rangelands). Journal of Biological Protection of Plants. 3(6), 15-26. (In Persian with English abstract).
  8. GhasemiAghbash, F., Abdi, A.A. and Heidari, M., 2017. Effect of forest roads on Iranian oak forest ecosystems in terms of sub-species diversity and physicochemical properties of soil. Journal of Biological Protection of Plants. 6(12), 59-76. (In Persian with English abstract).
  9. Hossini, S. and Hossini, S.A.A., 2016. Investigation of the stabilized and unsterilized sliding zone of forest road excavation due to vegetation diversity. Natural Environment Journal, Natural Resources of Iran. 69(2), 361-375. (In Persian with English abstract).
  10. Hossinzadeh, R., Soosani, J. and Razmahang, S., 2016. Investigation of the effect of road on the variation of wood species of Khorramabad oak forests (case study: Saman-e-Parak forests in Qhalegol region). Journal of Plant Research. 31(3), 80-91. (In Persian with English abstract).
  11. Jafari, A. and Askari, Y., 2016. Comparison of different biodiversity indicators in different sampling plans (Case study: Quaternary forests of Chaharmahal and Bakhtiari province). Environmental Research. 7(14), 135-144. (In Persian with English abstract).
  12. KaramiRad, S. and Abdi, A., Majnoonian, B., Etemad, V. and Sohrabi, H., 2014. Effect of forest road on grassland species and establishment of tree reforestation (case study: Kheyrood forest). Forest and Wood Products, Natural Resources Journal of Iran. 69(1), 29-40. (In Persian with English abstract).
  13. Lee, M., Manning, P., Rist, J., Power, S.A. and Marsh, C., 2010. A global comparison of grassland biomass responses to CO2 and nitrogen enrichment. Philosophical Transactions of the Royal Society B-Biological Sciences. 365, 2047-2056.
  14. Lotfalian, M., Riahifar, N., Fallah, A. and Hodjati, S.A., 2012. Effects of roads on understory plant communities in a froadleaved forest in Hyrcanian zone. Journal of Forest Science. 58(10), 446–455. (In Persian with English abstract).
  15. Margalef, M., 1958. Information theory in ecology. General Systematics, 3, 36-71.
  16. Menhenic, E.F., 1964. A comparison of some species individuals diversity indices applied to sample of field insects. Ecology. 45, 859-861.
  17. Naghdipoor, R., Poorbabaee, H., Heidari, M. and Noori, M., 2014. Investigating the effects of forest road on vegetation and some physical and chemical properties of soils (case study: Shafarood Forests, Series 2). Ecology of Forests of Iran. 2(3), 49-64. (In Persian with English abstract).
  18. Najafi, A., Hossini, S.M., Ezzati, S., Torabiverki, M. and Fakhkhari, M.A., 2010. Comparison of regeneration and biodiversity of trees in excavation trenches and jet roads with increasing distance (case study: Chamestan and Lavij forest, Noor). Journal of Science and Technology of Wood and Forest. 17(4), 139-152. (In Persian with English abstract).
  19. Shannon, C.E. and Weaner, A., 1949. The Mathematical Theory of Communication. University of Illinois Press, USA.
  20. Simpson, E.H., 1949. Measurement of diversity. Nature. 12, 1-20.
  21. Zadsar, Z., Shataee, S., Habashi, H. and Lotfalian, M., 2011. The effect of age of forest roads and distance from roads on the diversity of trees and shrubs. M.Sc. Thesis. Forestry and wood technology, University of Agricultural Sciences and Natural Resources of Gorgan, Iran. (In Persian with English abstract).
  22. Zeng, S.L., Zhang, T.T., Gao, Y., Li, B., Fang, C.M., Flory, S.L. and Zhao, B., 2011. Road effects on vegetation composition in a saline environment. Journal of Plant Ecology. 5(2), 206-218.