Early Growth Performance of Newly Planted Seedlings III Sarawak Botanical Garden

Kuching City has embarked on Sarawak Botanical Gardcn as one of the ideas for a green canopy in parallel with Wawasan 2020 mission and vision. Botanical Garden is defined as the careful management of trees as a whole for scientific purposes as well as recreational. Hence, this research is initiated to investigate the early growth performance of newly planted seedlings based on its survival rate and health status. The species composition, diameter at breast height, planting distance, chlorophyll content and stomata density of the leaves were measured. One hundred and fifty eight (158) seedlings planted in 2016 to 2017 at Sarawak Botanical Garden were evaluated . A total of 49 seedlings were in healthy condition, 43 seedlings were found to be unhealthy while 18 seedlings were dead. Forty three seedlings which were unhealthy could probably due to the unsuitable growing environment both above and below ground. The poor growth performance of the tree seedlings within twelve months may probably due to inadequate planting size and hence, the seedlings were vulnerable to both biotic and abiotic stresses. For example, the planting distance between seedlings was only 3 - 4 metres and seedlings like Koompasia exce/sa and Calophyllum macrocarpum were planted too close to the neighbouring trees. Some species cannot tolerate waterlogged areas except for Melalel/ca cajapllti and Shorea macrophylla. Another possible factor, most endemic species are known to be either shade tolerate or shade intolerant at the early stage of development. Shade tolerant species from the family of Dipterocarpaceae needs about 70% shade in the early seedling stage and thus exposure to sunlight will cause major injury to photosynthetic machinery which acts to breakdown the leaf chlorophyll. Shorea macrophylla recorded the lowest SP AD index among other species, indicating an impairment of leaf photosynthetic system and associated with a critical N deficiency. Calophyllum macrocarpum has thicker leaves with less number of stomata but are found in both sides of leaves. Inappropriate species selection could be hazardous to the public. The seedlings could grow into a maximum height of 45 metres and if it were planted too close to the pavement area, it could cause unwanted incidents to public. Seedlings that are poorly adapted to the site's environment are an unfortunate waste of human and economical resources. In order to improve the quality of urban landscape, it is recommended to increase the technical expertise and issues such as planting practices should receive greater attention. Trees that could last for decades play important role in recreating cities suitable for human enjoyment and for global sustainability