Estimation of seed oil yields of Chinese tallow tree in Japan
Field survey on the annual oil productions from the seeds of Chinese tallow tree (Triadica sebifera (L.) Small) was carried out for three years from 2009 to 2011 at five sites (Chiba, Shinagawa, Shinjuku, Nara and Nagasaki). The total numbers of fruits produced and the average numbers of seeds per fruit were measured on the basis of individual tree in the field at each season of the year. The average weights per seed and the average oil contents of seed were measured from the seed sample collected at each site in the first year. The annual oil yields per tree were calculated by multiplying the total weight of the seeds by the oil content. The seeds contained 30% oil on the basis of air-dried weight. The tree ages were determined by the yearly shoot elongation.
Chinese tallow tree began bearing fruits at 5-year old of tree age. In the first year, the oil yields per tree of Chinese tallow tree ranged 0.1-2.3 kg in Chiba, 1.0-3.7 kg in Shinagawa, 1.0-3.0 kg in Shinjuku, 0.009-0.013 kg in Nara and 1.6-3.0 kg in Nagasaki. The highest yields were found in Shinagawa. As compared with the yields in the first year, those in the second and third year were lowered in Shinjuku. Significant positive correlations were found on Chinese tallow tree between the tree age or the diameter at breast height (DBH) in Chiba, Shinagawa or Shinjuku and the oil yield per tree.
The oil yields per hectare were calculated using the fitted logistic equations of the oil yield per tree against DBH, those of DBH against the tree age, and the planting density (105 trees/ha for Chinese tallow tree). The oil yield could be reached at 200, 400 and 600 kg/ha/year at 16-year, 21-year and 27-year old respectively on Chinese tallow tree, while saturated over 15-year old Chinese tung-oil tree (Vernicia fordii (Hemsl.) Airy Shaw) at 400 kg/ha/year. The oil yields from 5-year old (the age at the beginning of bearg fruits) to 30-year old added up to 7,940 kg/ha for Chinese tallow tree and 8,680 kg/ha for tung-oil tree. These results indicate the productivity for the seed oil up to 30-year old of Chinese tallow tree is about the same as that of Chinese tung-oil tree.
|Chinese tallow tree