Comparing Increment Among Three Eucalyptus Clone Plantations In The Early Stage

When planted in different regions, eucalyptus clone showed a different growth performance. Any strain has itself specific constraints on life and geography, even the five clones also could be experienced physiological decline, such as decline in growth, appearance aging, increase in plant diseases and insect pests, and so on. Therefore, how to select suitable clones in line with region property has become the main task for eucalyptus researches and production in future. It is really emergent. In this contribution, a comparison test about three clones Eucalyptus urophylla x Eucalyptus grandis clone DH32-29 (DH32-29), Eucalyptus grandisxEucalyptus urophylla Guanglin NO.9 (GLGU9), Eucalyptus urophylla U6 (U6) was conducted in Nanxiao county, Liangqing district, Nanning, Guangxi province. The purpose is disclose the growth adaptability of the clones, providing a reference for the management of eucalyptus clones. Experiment design was taken randomized block design. In May 2011, the three clones was planted, and measured one time/half annual in the later three years. Comparison analysis of tree height (TH), diameter at breast height (DBH), individual volume and total volume was listed as followed:(1) the arrangement of total increment was DH32-29> GLGU9> U6.The total growth of TH for DH32-29 clone was 16.34 m, for GLGU9 clones was 13.98 m, for U6 clone was 11.91 m. Tree height increment during different period (0.5a-3a) was significant different among each clones. The total growth of DBH for DH32-29 clone was 12.55 cm, for GLGU9 clones was 11.75 cm, for U6 clone was 10.15 cm. There was no difference in DBH growth when the clones was measured for the first time (0.5a). However, the gap grew up as time went by and arrived at significant levels in 1-3 a. The individual volume in three years for DH32-29 clone was 143.975886 m3/hm2, for GLGU9 clones was 110.4218137 m3/hm2, for U6 clone was 72.621440 m3/hm2. There existed significant difference among each clone in 1-3a.(2) the arrangement of average growth is DH32-29> GLGU9> U6.Average TH increment of DH32-29 was 116.95%,137.28% times more than that of GLGU9 and U6, and the average TH increment of GLGU9 was 117.38% times than that of U6. Difference among the three clones was extremely significant. Similarly, average DBH increment of DH32-29 was 16.63%,123.67% times more than that of GLGU9 and U6, and the average TH increment of GLGU9 was 117.38% times than that of U6. The degree of average DBH increment differed from each other. The same situation also can be found in Average individual increment. That is, average individual increment of DH32-29 was 130.39%,198.25% times more than that of GLGU9 and U6, and the average TH increment of GLGU9 was 152.05% times than that of U6, and the gap among them was significant.(3) the arrangement of current annual increment for TH and DBH is 1th> 2th> 3th, for individual and total volume is 3th> 2th> 1th.In the first two year, tree height growth and DBH increment among the measured materials was significantly different, while difference could not be found in the third year. This is same for the current annual increment of individual volume and volume per hectare.