Periodical effects of automobile pollution on the growth of some roadside trees

The automobile exhaust significantly reduced the branch length and yield of Guaiacum offoconale, Azadirachta indica and Eucalyptus sp. The yield of Az adirachta indica, Eucalyptus sp. and Guaiacum officinale was lessened at th e polluted sites of the city. The increase in branch length of all the spec ies was found mainly in control as compared to polluted sites. The branch l ength and seed weight of G. officinale and Eucalyptus sp. reduced significa ntly (p <0.05) at highly polluted sites of the city i.e. M.A. Jinnah Road a s compared to control. Eucalyptus sp. showed maximum branch length (2.36 cm ) at campus (Control) as compared to Shaheed-c-Millat Road (2.04 cm) Liaqua tabad (1.97 cm) and M.A.Jinnah Road (1.82 cm), respectively in the month of July. However the lowest increase in branch length of Eucalyptus sp. (1.7 cm) was found at the highly polluted site on the forth week of observation in the month of June at M.A. Jinnah Road followed by Shaheed-c-Millat Road (2.0 cm) Liaquatabad (2.03 cm) and Campus (2.24 cm), respectively Azadirach ta indica showed maximum reduction in branch length at M.A. Jinnah Road (0. 94 cm) followed by Shaheed-c-Millat Road (1.18 cm), Liaquatabad (1.30 cm) a nd Campus (2.02 cm) on the forth week of observation in June. Guaiacum offi cinale showed the minimum branch length at M. A. Jinnah Road (1.94 cm) on e ight weeks of observation in the month of July.