This research is motivated by a lack of information about the riap of the Ulin (Eusideroxylon zwageri T et B) plant, both in the in-situ and ex-situ conservation areas. Ulin is one of the types of plants that are currently increasingly rare. Efforts to overcome the extinction of the ulin type and its breeding to maintain sustainability for it need to be known for its growth both in diameter and height. The purpose of this study was to find out the diameter and height of the ulin (Eusideroxylon zwageri T et B.) plant which is 9 years old in the ex-situ conservation area of State Agricultural Polytechnic of Samarinda. This research was conducted in the ex-situ conservation area of State Agricultural Polytechnic of Samarinda campus for 1 (one) year from December 2019 to December 2020 which includes, measurement of the diameter and height of Ulin (Eusideroxylon zwageri T et B) plants twice, data processing and writing. Based on the results of current annual increment calculations the height of the Ulin (Eusidroxylon zwageri T et B) plant is 1.08 m and the diameter is 0.30 cm, while the mean annual increment is 0.78 m and the diameter is 0.84 cm.

Keywords : Ulin, Increment, Height, Diameter, ex-situ conservation.