More systematic efforts started in the early 20th century. Prime Minister Chandra Shumsher Rana (1901-1929) expanded Kathmandu’s road network and planted trees, introducing new species like Monkey puzzle (Araucaria araucana). Juddha Shumsher Rana (1932-1945) continued planting trees to beautify the roads like Putali Sadak, particularly after the devastation of the 1934 earthquake.
Modern urban environmental planning began during the Panchayat in the 1960s and 1970s. The government renovated roads, mandating the planting of either a single line or double line of roadside trees. Part of the newly constructed Arniko Highway (Kathmandu to Kodari) and the Ring Road encircling the capital, had rows of trees on either side.
In the 1980s, urban planners suggested three lines of green belt alongside the roads instead of previously mandated one-line roadside trees. As a result, more than a hundred thousand fast-growing trees were planted around the Ring Road.
Rana and Panchayat planners were wrong to pick roadside trees such as poplars and eucalyptus based primarily on aesthetics and their fast-growing nature. In recent decades, Nepal has been steadily expanding its road network while integrating green belts, but planners have neglected the inclusion of criteria on species selection.
Over time, attempts have been made to suggest a more scientific species selection. Researchers have recommended over 300 potential species for urban forestry in Kathmandu, including a comprehensive list of suitable species that could be planted alongside roads. The list includes native and exotic trees and ornamental plants. These suggestions have been largely ignored.
Mitra Pathak, research officer at the National Botanical Garden in Godavari says, “It is unscientific, we are planting whatever saplings are easily available.”
Ecologically, the majority of trees planted around Kathmandu are misfits. Swami (Ficus benjamina) for instance is a weed, whilst Grevillea robusta, a deciduous branchy species, and Raj Sallo (Cupressus torulosa), are climatically unsuitable for the city.
Urban environment expert Ramji Bogati also laments the lack of ecological criteria. “We should take into account factors like location, soil, nature of the species, in selecting roadside trees,” he says.