A Study of the Primary Growth of Casuarina junghuhniana Provenances in Taiwan

This study was undertaken as a part of international provenance trials of Casuarina junghuhniana coordinated by CSIRO, Australia. The present trial compared 28 provenances of C. junghuhniana from natural occurrence and land races, and variations in 12 growth and morphological characteristics were assessed in 2-yr-old stands at 4 sites in Taiwan. Considerable genetic variations among natural provenance and land races of C. junghuhniana with a significant site-by-provenance interaction were revealed. Provenance nos. 16, 17, 18, 19, and 20 from Timor Island, Indonesia, and no. 21 from Old Uhak NE Wetar, Indonesia, were selected as the superior seed sources for all 4 sites, based on Scheffe’s multiple range tests of their survival rate, height, and diameter growth. Regression analyses of data obtained in the Suhu coastal area and Taichung Harbor area revealed a significant negative relationship of elevation with survival percentage, height, and diameter growth of C. junghuhniana. A significant positive relationship was observed for the survival rate of C. junghuhniana and the longitude and elevation of the Duona area. Results from both cluster and factor analyses with a principal component solution suggested that the 28 provenances could be classified into 3 geographical groups. The first group originated from Old Uhak NE Wetar, Indonesia and was far distant from the other provenances. The second group consisted of 5 provenances from Timor, with the remaining provenances being classified into the third group. These results suggest that the ecoclines of C. junghuhniana might be affected by elevation