Appraising Of Growth Characteristic And Economic Efficiency Of Eucalyptus Urophylla×E.Grandis Clone Plantation

The biomass, productivity, stand growth and economic efficiency ofEucalyptus urophylla×E. grandis plantation(1.5 to 4.5 years old) werestudied in 3.5 years period. The results showed that the biomass and standgrowth increased with the increased of their ages, the biomasses of single tree ofEucalyptus urophylla×E. grandis stands respectively were 30.07kg,85.50kg,146.42kg and 202.38kg, arborous layer biomasses of Eucalyptusurophylla×E. grandis plantation respectively were44.75t·hm^-2,124.99t·hm^-2,199.80t·hm^-2and 267.14t·hm^-2.There were evidentdifferences in top-down model of the biomass of different organs indifferentage-stage plantation. Net primary productivity of arbor increased with theincreasing of their ages. The maximum net primary productivity in organs wasbole, the minimum was radicel.The height,DBH and stand volume of Eucalyptus urophylla×E. grandisplantation arboreous layer are obvious increase by age increase. According tothe comparison between urophylla×E. grandis clones DH32-29,DH32-28and Urophylla U6,the height, DBH and stand volume are obvious or very obvious different, according to the DBH and height stand distribution, the DBHand height sample of all of the three clones plantation go to lognormaldistribution. Different age of this three clone plantation, the dispersed of heightand DBH will increase by age increase, The least dispersed of DBH isEucalyptus urophylla×E. grandis DH32-29, just 15.8%, The least dispersed ofheight is Urophylla U6, It means DH32-29 and U6 growth more uniform inDBH and height, and DH32-28 more dispersed. By using different models formodeling and choosing the best growth from Uroghylla U6, urophylla×E.grandis DH 32-28 and DH32-29, stand average height forecast model is.H=c0×(1-exp(c1×A))^1/(1-C2); DBH forecast model is: D=c0×(1-exp(c1×A))^1/(1-C2);average stand volume growth forecast model is:V=c₀D^C₁H^C₂.From the plantation project economic efficiency evaluation we can see, theROI, profit and tax investment ration and IRR of urophylla×E. grandisDH32-28 and DH32-29 are bigger then U6. the profit, tax capability andendure of mortgage rates of urophylla×E. grandis DH32-29 and DH32-28plantation establishment project ara much stronger than Uroghylla U6, The PTof Uroghylla U6 is 3.84 year, Eucalyptus urophylla×E. grandis DH32-29 andDH32-28 is 2.81 year and 2.91 year, much shorter than U6, It means theeconomic efficiency of urophylla×E. grandis DH32-29 and DH32-28plantation establishment is more evident than Uroghylla U6.