The project collected data from 2235 study plots and conducted stem analysis on 1190 trees of 08 chosen species, based on which empirical statistical models, and site class and yield tables of each species were developed. Volume-height and volume-diameter equations or stem profile equations were used to construct new volume tables, merchantable volume tables and merchantable product ratio tables. To calibrate volume tables of three species (Acacia hybrid, Acacia mangium and Eucalyptus urophylla), the test data were collected from plots where all trees were clear felled in harvesting stands. The stems were then analyzed by stand, averaging individual trees separately in three diameter classes. As for the site class tables, test data were retrieved from the stem analysis results of averaged trees in the dominant tree layer. Only study plots that shared the same site class, the same age and the same initial density were selected to calibrate the former yield tables.

The main results of the project were, as follows:

(i) Inventory tables constructed for A. auriculiformis, P. merkusii, P. kesiya, P. massoniana, and volume tables of P. caribaea were considered still reliable and suitable for the current plantation of these species.

(ii) Table calibration: the former site class tables and yield tables for A. auriculiformis were updated.

(iii) Inventory table construction: With regard to Acacia hybrid, A. mangium, E. urophylla, due to the substantial differences between the recent growth data with the data that were used to develop the former tables, new volume tables, yield tables and site class tables were developed. New tables of A. mangium and E. urophylla are to provide information about medium to large sized saw logs. As for Acacia hybrid, because trees of large size are often hollow and porous inside, yield tables were constructed up to the age of 8.

(iv) Merchantable volume tables were developed for three major plantation species namely Acacia hybrid, A. mangium and E. urophylla, (volume of wood excluding firewood).

(v) Tables of merchantable weights and carbon biomass were developed for all species studied.

(vi) With regard to Acacia hybrid, A. mangium, E. urophylla and P. caribaea, tables of merchantable volume ratios (lumber) were constructed.

(vii) The project developed a table management program with an accompanying manual. It allows users to look up information and manage available tables.

From the study, recommendations were proposed as follows: (1) to construct yield tables of primary plantation species with varying stand densities. These tables will take into account the diversity of small-scale plantations and silvicultural techniques in forestry sectors in Vietnam. (2) to establish a system of permanent plots for plantation species in different sites and ecological zones to monitor long-term silvicultural experiments. The permanent plots will help to assess the combined effects of environmental and management factors on the growth and development of plantations.