Assessment of structure and governance of amenity trees in the premises of International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria

Abstract

Amenity trees are components of the urban forest which contribute significantly to human wellbeing and improves environmental quality. Benefits derivable from amenity trees are numerous but inadequate or lack of knowledge of the structure of the urban treescape as well as poor or no management practices like institutional framework has limited these benefits. A number of institutions has lot of trees planted within their premises. However, more often than not, those trees have become hazardous and threats over time because of undesirable features and unsuitability of such trees for the urban ecosystem as well as no provision or inadequate and ineffective governance framework for sustainable management of such urban green space. Many people also have some negative view and attitude towards trees as a result of their belief thereby making it difficult for them to embrace the practice of tree management and conservation within working and living premises.

This study assessed the structure and governance of amenity trees on IITA, Ibadan premises. Tree enumeration using walking survey was carried out in the premises of IITA, Ibadan to identify and determine tree species population, while selected attributes were used to determine the suitability of the identified tree species for amenity purpose. People perception on amenity trees in the study area was assessed using an online survey. A total of 1050 respondents were involved in the survey and 167 responses were received and analyzed. Tree management data were obtained using questionnaires administered physically to the head of department’s in charge of trees on the campus and all data obtained through survey were subjected to descriptive analysis.

A total population of 2626 trees from 126 species and 42 famillies were identified in the premises of IITA, Ibadan. The highest tree population (525) was recorded in the Tropical cresent residential area within the living premises with Largestromia speciosa (321) being the most dominant species, accounting for 61.1% of the tree population in the crescent. The urban landscape of IITA has a high diversity with Elaeis guineensis accounting for 19.92% of the tree population. Of all the benefits derivable from amenity trees on IITA campus, cooling the environment and beautification ranked the highest with 82.6% each, and next to this is provision of shade with 71.8% as parts of the benefits derivable from trees. The NDVI values obtained over the years show that there was a change in the trend of green space over the years but the trend tends to increase in year 2020 after a decline in year 2000. This study revealed that both the population and species diversity of trees on IITA Ibadan premises were high and well managed. Hence, IITA management practices and institutional framework for treescape over the years can be adopted by other institutions in Nigeria for proper urban forestry development.