TITLE:
Revision of the Volume Function of Ayous (Triplochyton scleroxylon) for Sustainable Management of Forest Resources in Cameroon
AUTHORS:
Rodine Tchiofo Lontsi, Adrien Charnel Gueti Diapa, Bonaventure Nteukam Kakem, Mbezele Junior Yannick Ngaba
KEYWORDS:
Forest Management, Volume Function, Standing Timber, Triplochyton scleroxylon, East Cameroon
JOURNAL NAME:
Open Journal of Forestry,
Vol.16 No.2,
April
16,
2026
ABSTRACT: During forest management in Cameroon, estimating the volume of standing timber is crucial before dividing the forest into annual cutting units and developing the industrialization plan of the logging company. Forest managers use volume functions from the software called TIAMA, but discrepancies between estimated and actual volumes have been noted. The study aims to evaluate the bias in actual estimation of standing volume of Triplochyton scleroxylon (Ayous), and to develop and test a new volume function for this species. Ayous was chosen due to its commercial value and its diameter range in the studied area. The study was conducted in the Forest Management Unit (FMU) 10035 located in the East region of Cameroon, using a sample of 177 Ayous trees. TIAMA’s volume function applied to the sample showed a significant bias, with an average of 0.81 m3 per stem. Consequently, a new volume function was developed to predict merchantable stem volume for Ayous in the area: V = 38.0907 − 0.644838 × D + 0.0037344 × D2. This new volume function was tested against others, revealing that it provides less biased volume estimates. Moreover, volume estimates with it show no significant difference when compared to felled volume. Therefore, the adjusted volume functions are recommended for FMU-10035, to ensure more accurate timber volume estimations and improve forest management decisions.