Associate Professor Hai has been both a manager and a scientist at the Vietnamese Academy of Forest Sciences since 1994. Currently, Assoc. Prof. Hai is managing the scientific and technological fields at the Academy.

His research area focuses on genetic breeding of acacia and eucalyptus species, plant propagation, conservation of forest plant genetic resources, sustainable forestry and restoration initiatives. Some of his major contributions include many new varieties that are serving the development of the forestry sector in Vietnam, seed bank, field gene bank and participation in extension and training programs for foresters, research staff and post-graduate students in the Academy and some forest universities. He has to his credit several research papers and books/chapters.