Pinus kesiya International Provenance Trials: Overview

bullet1 Swaziland

bullet2 History of trials

Details of the trials sites and trial design can be found in the full report for Swaziland (download now).

Two trials were established in 1972 by Usutu Pulp as part of the first international series of trials. The trial sites represent a low altitude planting site (770 m) and a high altitude site (1460 m). 9 seed lots of P. kesiya were tested plus P. patula and P. elliottii controls. Of the P. kesiya sources, 7 have origin in the Philippines, one is a land race from Zambia (of Vietnamese origin) and the last source is a landrace from Malawi of unknown origin. Results are presented by Morris (1984). He concluded that:

  • Ranking of provenances differs depending upon the measure of growth, which is made. Analysis of height, diameter and volume production per ha. do not give the same ranking. This is because of differences in stem taper and survival at establishment;
  • Volume production of P. kesiya is superior to P. elliottii at lower altitudes and slightly inferior to P. patula at higher altitudes;
  • The stemform of P. kesiya is inferior to both P. patula and P. elliottii and is a serious limit to its value for pulp production at Usutu;
  • Although there is some variation in vigour and form between P. kesiya provenances this is not so great as to influence the two conclusions stated above;
  • Use of P. kesiya as a major species in the Usutu Forest is dependent upon a seed source giving trees with acceptable form and upon the long term influence of pine woolly aphid on tree growth (Morris 1984).

Present series of trials (R136)

Usutu Pulp has established three trials of P. kesiya as part of the new international series of trials initiated in the late 1980’s. The trials are situated in the G-Block, J-Block and A5 respectively. The trial in the G-Block is at low altitude (800 m) and gentle slope. Block J is a higher altitude site (1100 m) and at a steep slope. The A5 trial is also at high altitude (1120m) and represents a different land type to the  J-Block. Compared to Block G and J, A5 is a smaller trial with fewer entries and smaller plots. Because of time constraints, the A5 trial had to be left out of the field assessment, and the assessment and analysis hence only encompass the trials in Block G and J.