Tree biodiversity in Bornean lowland forest: What are the key species for forest city development in the new capital city of Indonesia?

PLOS ONE | https://doi.org/10.1371/journal.pone.0320489 April 8, 2025 13 / 19 PLOS ONE Tropical urban tree selection Rehabilitation strategies The development of IKN needs to integrate environmental and forestry issues, including wild- life home ranges and habitat protection within the landscape. Currently, forest plantations of Eucalyptus spp. cover a considerable proportion of the landscape within IKN. Nevertheless, they will be replaced by native and endemic species of lowland tropical forest of Kalimantan as we discuss here. There are four strands encompassing successful strategies for rehabilitation in order to achieve the target of green cover of 75%, which are forest rehabilitation, land rehabilitation, reclamation, and social forestry (Table 6). Rehabilitation and reclamation are defined accord- ing to Peraturan Pemerintah No. 26/2020 [66] on Forest Rehabilitation and Reclamation. Initially, forest rehabilitation aims to recover degraded forest. This can then be expanded to other issues, since factors contributing to forest degradation are complex. Forest rehabilitation is now not only considered from the point-of-view of forest recovery but also that of local prosperity. Nawir et al. [67] offer recommendations in implementing successful rehabilitation: (1) good knowledge on rehabilitation sites (soils, topography, local culture, local wisdom), (2) seed source availability, (3) local community participation, (4) project sustainability, and (5) clear land tenure. The development of IKN needs to integrate environmental and forestry issues, including

wildlife home range and habitat protection within the landscape. Based on Law No. 3 of 2022 concerning the National Capital, 75% of the area will be maintained as green space (65% forest + 10% food source plants). The regional spatial plan of IKN [53] allocates protected areas in IKN as a component of the forest city implementation. The five types of protected areas in the spatial plans are: environmental buffer areas and food security; local protected areas (protec- tion to coastlines, riverbanks, and around lakes or reservoirs); green open areas (urban forest, Table 6. Rehabilitation strategies in the proposed Ibu Kota Negara area, East Kalimantan, Indonesia. Strategy Objective Coverage Implementation Forest Rehabilitation Restore, preserve, and increase forest function to improve car- rying capacity, productivity, and functions to maintain life support systems Conservation forest (except Nature Reserve and National Park core zone), Production Forest, and Protection Forest - Intensive reforestation (Crit- ical land with zero commu- nity activity) - Agroforestry (Critical land with community activity) Land Rehabilitation Restore, preserve, and increase land function to improve carrying capacity, productivity, and functions to maintain life support systems Outside forest area with forest cover or land area Revegetation with the scheme: - Private forest - Environmental revegetation - Urban Forest (Settlement area, industrial area, rec- reation area, biodiversity sanctuary area, protection area) Forest Reclamation To improve or restore the

degraded forest area to functioning optimally and according to the designation Degraded forest with land and vegetation change due to utilization Revegetation with tree planta- tions and maintenance in the post-use forest to restore and recover degraded vegetation Social Forestry Local communities as a principal element in the sustainable forest management to improve prosper- ity, environmental balance, and social/cultural dynamics State Forest, Private Forest, and Indigenous Forest Village Forest, Indigenous Forest, Community Forest, Community Plantation Forest, and Forestry/Conservation Partnership Source: [66]. https://doi.org/10.1371/journal.pone.0320489.t006