Báo cáo khoa học: "Comparative growth analysis of five first year establishment poplar clones (Populus sp.) grown under a short-rotation intensive culture system"

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Comparative growth analysis of five first year establishment poplar clones (Populus sp.) grown under a short-rotation intensive culture system F. Mau I. Impens Laboratory of Planty Ecology, Department of Biology, University of Antwerp, Universiteitsplein 1, Wilrijk, Belgium 2610 Introduction intensive culture is obvious. Clones from and Tacamahaca sections are Aigeiros Interest in fast growing poplar clones for well suited for short-rotation intensive cul- maximum production in short-rotation ture because of their rapid juvenile growth.
’Fast starter’ clones are most suited for a 1-3 yr old coppice stand rotation ac- cording to Zsuffa (1979). Superior hybrid growth was indicated as a factor respon- sible for the good performance of hybrid poplar in comparison with mere species clones (Cain and Ormrod, 1984). Materials and Methods Five poplar clones: P.x euramericana cv. Robusta; P. trichocarpa cv. Fritzi Pauley; P. tri- chocarpa cv. Columbia River; P. trichocarpa x P. deltoides cv. Beaupr6; P. trichocarpa x P. Primary parameters, such as basal diameter deltoides cv. Raspalie; were grown from cut- and height, were measured every 2 wk for each tings planted in a 0.80 x 0.80 m pattern at plot consisting of 81 trees. Height was mea- Afsnee (51 °02’N, 3°39’E; Belgium) in 1987. The sured to an accuracy of 0.5 cm by means of a trees were well irrigated, fertilized and the plots measuring rod and diameter was determined on kept free of weeds. each stem with a vernier caliper 22 cm above
Robusta and Columbia River with respec- level. Other parameters, such as num- ground bers of leaves, height of leaf implantation and cm. Robusta ended tively 169 and 180 leaf orientation, were monitored on 8 model around Julian date height growth early trees of each clone. Leaf development, leaf 261 (Fig.1). ). demography and leaf area distribution were stu- died in relation to aboveground leaf and wood Stem diameter was the largest with biomass productions. Leaf area was calculated and Raspalje (20 and 22 mm), Beaupré from allometric relations between leaf area and while the diameter growth of Robusta had leaf dimensions. Seasonal growth was also analyzed in terms of relative growth rate already culminated around Julian date 247 (RGR), net assimilation rate (NAR) and leaf (Fig. 2). area ratio (LAR) with RGR NAR x LAR. At the = end of the growing season, biomass production Maximum leaf area was reached around was estimated by destructive sampling and Julian date 286, Raspalje and Beaupré weight-surface (leaves) weight-volume or having considerably higher leaf areas (stems) relationships. (about 1 m than the other clones. ) 2 Robusta had the shortest period of leaf retention, in comparison with Columbia Results and Discussion River for which 50% of the leaf area was retained until 3 wk later (Fig. 3). Leaf area duration data (Table I) emphasize the Stems of Raspalje, Fritzi Pauley, Beaupré large differences among clones. (about 227 cm) were higher than those of
The RGR decreased from the beginning Acknowledgments of the season, as was also shown by Far- mer (1980), and became negative (leaf study was supported by the I.W.O.N.L. This fall) at the end (Fig. 4). The NAR was also (Brussels, Belgium) file no. 860370. diminishing giving negative values at the end of the growing season and showing a large difference between Robusta and References Columbia River at that time (Fig. 5). The LAR decreased throughout the season; Cain N.P. & Ormrod D.P. (1984) Hybrid vigour Columbia River always had the highest as indicated by early growth characteristics of ratio (Fig. 6). Populus deltoides, P. nigra and P. x eurameri- cana. Can. J. Bot. 62, 1-8 Aboveground dry biomass production varied by a factor of 2 between the most Comparative analysis of Farmer R.E. Jr. (1980) productive clone (Raspalje) and the least tree species. 1 st-year growth in six deciduous productive one (Robusta). The ratio be- Can. J. For. Res. 10, 35-41 tween leaf dry biomass and total above- features and prospects of (1979) The Zsuffa L. ground dry biomass, however, was about Ontario. In: Poplar Re- poplar breeding in the for all clones at maximal above- same search, Management and Utilization in Cana- standing crop (Fig. 7; ROB = 0.33, ground da. (Fayle D.C.F., Zsuffa L. & Anderson H.W., eds.), Ont. Min. Nat. Resources For. Res. Inf. 0.27, BEA = 0.30, COL FRI .30, 0 = = Paper #102, 1-1 to 1-6 RAS 0.30). = performing hybrids were Ras- The best and Beaupré. In contrast, Robusta palje had the lowest values for most of the growth parameters evaluated.