MICLAT, SONNY BOY V. July 2022. PROPAGATION OF BROAD-WINC] APITONG (Dipterocarpus kunstleri King) THROUGH AIR LAYERING USIN COCOPEAT SUBSTRATE AND ROOTING HORMONE. BACHELOR © SCIENCE IN FORESTRY, FOREST RESOURCE MANAGEMENT. PAMPANG, STATE AGRICULTURAL UNIVERSITY MAGALANG, PAMPANGA. Adviser: FOR. LUISITO B. TERBIO The study was conducted at Broad-winged Apitong Ramet located at Clonal Nursery, Pampanga State Agricultural University, PAC, Magalang, Pampanga in the propagation of Broad-winged Apitong (Dipterocarpus kunstleri) through air layering using three treatments: Topsoil (T1), Cocopeat (T2), and Cocopeat with hormex rooting hormone (Thiamine Hydrochloride 0.25%, Naphthyl Acetic Acid 0.24%, and Indole Butyric Acid 0.013%) (13). The growth parameters such as shoot length and shoot diameter were measured every 15 days of data collection. The number of leaves produced was counted every 15 days and the survival rate was taken after 15 days of transplanting. In terms of the number of leaves produced, T3 as a rooting medium showed significant results among treatments after 45 days with a 5°o level of significance. It recorded the highest number of leaves produced (1.6), followed by T2 with a 0.4 increment. Analysis of Variance revealed that all treatments had no significant differences in terms of shoot diameter after 90 days of air layering. In terms of shoot length, Ts recorded an average increment of 8.1 centimeters in 15 days of the study. It was relatively higher compared to Ti ( Topsoil )} and T2 (Cocopeat), which have 1.86 and 2.46 increments, respectively. Analysis of Variance revealed that T3 was highly significant among the treatments, with a 1% level of significance after 15 days. After 90 days of air layering, all the samples survived, but most of them did not root. After 15 days of transplanting, the survival percentage was higher in Ts (33.33%) followed by T2 (20° 0). The lowest survival rate was observed in T; (6.67° 0).