Analysing of Tree Carbon Stock on Green Open Space Area in The Upstream of Kali Bekasi Watershed

Abstract

The upstream of Kali Bekasi watershed condition plays an important role on the management of Kali Bekasi watershed, Jakarta and Bogor District. The presence of vegetation cover in sufficient area in the Permanent Green Open Space of upstream of Kali Bekasi watershed is crucial in maintaining environmental quality. CO2 sequestration by the presence of vegetation in a landscape is substantial mitigation of climate change. It creates a low carbon society that is needed to get appreciation in environmental services. The objective of study was to analyze structure and species diveristy of stands, to analyze changes of the permanent green open space in upstream of Kali Bekasi watershed, its carbon stocks and their correlation. Observation plots amounting to 161 plots were established in the study site, which were laid out on the upstream of watershed, representing upper, middle and lower parts of the site. Estimation of carbon stocks was calculated by using non-destructive sampling method, using the existing allometric equations. The results of vegetation analysis showed that the level of Shannon-index was low until medium, 0,63 and 3,36 respectively. These species were identified to have high carbon sinks, which is potential to increase carbon stocks and biodiversity conservation. Stand structure in the agroforestry system in the upstream of Kali Bekasi watershed was found closely to natural forest structure. The upstream of Kali Bekasi watershed has 1,63x106 tons carbon stock total equivalent 5,97x106 tons of CO2 uptake. Green open space in a private area (mix-garden, home garden, bamboo garden) most contributed to the total carbon stocks although the average carbon stock was lower than in pine forest and natural forest. The changes in permanent green open space area have the greatest influence on total carbon stocks. Carbon stocks were highly related to the basal areas, but stand density and species diversity has lower correlation to carbon stocks.

Kondisi Hulu DAS Kali Bekasi berperan penting dalam pengelolaan DAS Kali Bekasi dan Kabupaten Bogor secara umum. Keberadaan tutupan vegetasi dengan luasan mencukupi pada RTH Permanen di Hulu DAS Kali Bekasi sangat berperan dalam menjaga kualitas lingkungan. Keberadaan vegetasi yang mampu menyerap karbondioksida dalam suatu lanskap sangat diperlukan untuk mitigasi perubahan iklim yaitu menciptakan masyarakat rendah karbon (low carbon society) serta perlu mendapat apresiasi sebagai salah satu jasa lingkungan. Penelitian ini bertujuan untuk : 1) menganalisis struktur tegakan dan keanekargaman jenis di Hulu DAS Kali Bekasi, 2) menganalisis perubahan Ruang Terbuka Hijau (RTH) permanen DAS Kali Bekasi bagian Hulu, 3) menganalisis cadangan karbon pohon pada Ruang Terbuka Hijau (RTH) permanen DAS Kali Bekasi bagian Hulu saat ini, 4) menganalisis korelasi cadangan karbon pohon dengan struktur komunitas vegetasi. Analisis cadangan karbon dilakukan dengan membuat 161 plot pengamatan yang tersebar pada Hulu DAS Kali bagian atas, tengah dan bawah serta mewakili masing-masing tipe RTH Permanen yang ada di Hulu DAS Kali Bekasi yaitu Hutan Alam, Hutan Pinus, Kebun Campuran, Kebun Bambu dan Pekarangan. Pendugaan cadangan karbon dilakukan secara non destruktif dengan menggunaan persamaan alometrik yang sudah ada. Analisis cadangan karbon dalam skala lanskap dan perubahannya dilakukan dengan melakukan interpretasi tutupan lahan pada citra Avhnir-2.