Research Trends for Improvement of Biotope Area Index

The Biotope Area Index (BAI) is an indicator applied to the field in various types of spaces such as apartment complexes, business and educational facilities. However, the BAI would be requested for the supplement and improvement reflected by practical approaches. Therefore, this study was conducted through comparative analyses of foreign indexes similar to the BAI and previous studies in order to improve the BAI. The research process consists of reviewing the actual application of the previous BAI, and comparing and analyzing the types and weights of foreign BAIs. Seoul Metropolitan Government adopted Germany’s biotope index in 2004 and many studies on the assessment of the BAI through simulation or actual projects were carried out. Green spaces on artificial grounds are used similarly in all indexes, but different weights are applied in some areas. Germany gives the weight of 0.7 to green roofs regardless of soil depth, but under the BAI criteria, green roofs with the soil depth of more than 20 cm are given with the weight of 0.6, while those with the soil depth of less than 20 cm are given with the weight of 0.5. Distinctively, green roofs weights are given differently based on the soil depth of 80 cm and 10 cm in Sweden and United States respectively. In United States, bonuses are additionally given to drought tolerant, native plant species, or landscape areas where at least 50% of annual irrigation needs are met and plant types are further divided into sub-groups. BAI studies have mainly been conducted on spatial types and weights. Establishment of the systematic framework as a environmental planning indicator, consideration of the potentiality as a quantitative indicator, overcoming limitations as a two-dimensional indicator, and enhancement of a functional role of estimation index by tree planting could be necessary for BAI improvements.