Experts believe that in order to save precious trees that have fallen, especially ancient trees, it is necessary to prune branches and canopies, then re-erect them and expand the planting area to provide space for root development.
The Yagi storm caused approximately 17,000 trees to fall across the city of Hanoi, including around 2,000 urban trees. In a response document regarding the aftermath of the Yagi storm on September 8, Chairman of Hanoi City, Tran Sy Thanh, requested related units to mobilize all personnel and equipment to clear fallen and broken trees to ensure traffic safety. Conservation efforts will focus on rare and valuable trees, and small trees with a diameter of less than 25 cm that have fallen will be assessed for replanting on-site or taken to nurseries for care.
Dr. Trieu Van Hung, a forestry expert and former Chairman of the Vietnam Forestry Science and Technology Association, stated that ensuring fallen trees survive and grow requires pruning branches and canopies. Before replanting, it is essential to widen the area of the planting pit to allow for root system development.
For newly replaced trees or those wrapped in burlap or plastic, the wrappings need to be removed. “If the wrappings are left on, the roots will struggle to penetrate the soil, which limits root development, making the tree weaker and more susceptible to being uprooted in strong winds,” he explained.
He advised consulting experts when selecting urban trees according to established standards and specific criteria for each type of tree, such as those planted along streets, in parks, and schools, considering aesthetics, environmental impact, and color. “Currently, there are specific criteria and regulations for planting large trees; it is necessary to conduct thorough surveys regarding the area and space of each location,” he noted.
Red sưa tree uprooted on Hang Dau street. (Photo: Ngoc Thanh).
Associate Professor Dr. Dang Van Ha, Director of the Institute of Landscape Architecture and Urban Greenery at the Forestry University, believes that the planting pit creates an environment that helps the tree develop its root system during the nurturing process. However, when planting in a new location, it is necessary to remove the protective wrapping so that the roots can adhere to the soil. “Some opinions suggest leaving the entire wrapping intact to keep the soil secure, which is a mistaken view,” he stated.
Dr. Ha noted that according to natural laws, some tree species lose their taproots as they grow and develop lateral roots, while others grow deep taproots. When trees are harvested and planted in urban areas (mostly large trees), the taproot systems are usually cut off, allowing only the lateral roots to develop. The larger the tree, the more root sections are cut, making it difficult to recover the entire root system; this is a common issue with urban trees today.
“Another disadvantage is that the size of trees planted in urban areas is not clearly defined, with some streets planting trees with diameters up to 15-20 cm, which is very dangerous,” he emphasized, adding that it is better to choose smaller trees with diameters of 8-10 cm, ensuring the preservation of the main taproot for future growth.
According to Dr. Ha, each urban area has its own unique characteristics regarding natural conditions and spatial architecture. Therefore, it is crucial to plan and select the right types of trees that fit the characteristics of each landscape space in every urban area. Especially for street trees, which are affected by infrastructure and human factors, careful monitoring is necessary.
As a result, Dr. Ha assessed that urban greenery requires attention from the selection of species and sizes at planting to preparing surrounding soil that is fresh, loose, and aerated for root development. “When the surrounding area is cramped, roots will only develop within a narrow range, while dense foliage that is not frequently pruned can easily break in storms,” he remarked.
Dr. Vu Ngoc Long, former Director of the Southern Ecology Institute, agrees. He believes that when planting trees in urban areas, it is essential to follow proper techniques for removing the protective wrapping to help the tree establish roots in the soil.
The former Director of the Southern Ecology Institute noted that trees planted on sidewalks in large cities and residential areas often have their taproots cut off because they grow deep into the ground, making it difficult to recover them entirely. After harvesting, growers apply growth stimulants to help the tree recover its root system.
Dr. Trieu Van Hung, former Chairman of the Vietnam Forestry Science and Technology Association, pointed out that currently, each planting pit is only 1.2 – 1.5 meters wide, which is too small for the root development needs of urban trees. “The simplest solution is to create a pit that is wide and deep enough for the tree to grow comfortably, ensuring it establishes a secure root system,” he emphasized.
Giang Van Minh street leading to Kim Ma (Ba Dinh), two ancient trees with a trunk diameter of 1 m blocking the road, preventing residents from passing. (Photo: Ngoc Thanh).
According to statistics from the Technical Infrastructure Management Center of Hanoi (Hanoi Department of Construction), the shaded trees in Hanoi are rich and diverse, comprising 175 species from 55 plant families. In the 12 districts, there are over 8,000 ancient trees (with a minimum age of 50 years or a trunk diameter of 50 cm or more at a height of 1.3 m) including major species such as: banyan, lagerstroemia, chayote, jackfruit, orchid, rosewood, black lim, camphor, black locust, milk flower, star fruit, sour, red sưa, mahogany, and phoenix tree.
