Elimination trial of 10 Poplar clones (Populus nigra) in Kermanshah province

In order to select and introduce the promissing clones of Populus nigra, 10 clones were planted 3*3 m in two research stations (Mehregan and Eslamabad) of Kermanshah province. The statistical design of the experiment was randomized complete block with three replicates. At the end of each growing season, diameter at breast height and height of trees were measured. Moreover, at the last year other factors such as collar diameter, media diameter, top diameter and weight of trees were measured as well. The results after 8 years showed that Populus nigra 62.154, P.n. 56.75, P.n. betulifolia, P.n. mehrgan, P.n. 56. 32 and P.n. 56. 52 are the most promissing clones. The mean diameter of clones varied between 20.7 and 21.9 cm, mean height between 15.2 and 16.9 m and mean volume increment varied between 32.3 and 39.2 m3ha-1y-1

Impact of stump cutting on growth of different Poplar clones in a selective nursery, Gorgan

The expansion of Poplar plantations has been stated to play a decisive role by increasing the amount of wood production, reducing the wood import as well as by creating employment rate in wood and paper industry. Here, a number of 34 native and exotic Poplar clones were explored in a two-year study in a selected nursery of the Chalaki research station in Gorgan. The aim was to examine the effects of stump cutting on the growth in different ages (1/1 and 1/2 age), the results of which will support the decision making process when choosing the suitable clones for Poplar plantations. The sample seedlings were provided by planting 100 cuttings in 20×130 cm spacing grid. The examined clones were selected from 6 species including Populus nigra (12 clones), P. alba (6 clones), P.x.euramericana (9 clones), P. deltoids (5 clones), P. trichocarpa (one clone) and P. caspica 80.4 (one clone). Following the first growth period, all seedlings were cut from the ground level. In the subsequent year, half of the seedlings (i.e. one-year old stems and two-year old roots) were bred. Then, Collar diameters and heights were measured for all the seedlings, followed by calculating the mortality rate and the rate of growth change. The one-way analysis of variance (ANOVA) and Duncan test were used for comparing the means. The stump cutting was shown to bear a significant positive effect on the growth rate as well as on the uniformity of the seedlings in different clones. The changes in height growth among different poplar groups showed a significant difference (

Determining the best stem form factor equation for populous deltoides in poplar plantations of Alborz Research Station, Karaj

Populous deltoides has been proven to exceed other poplar clones in terms of growth and wood production per unit area. Thus, it is generally considered as one of the most crucial species for pulp and paper-oriented wood plantations in Iran. Here, a number of 40 trees was selected for developing true form factor (TFF) of P. deltoides. Prior to felling, the height and diameter of trees were measured. Following the felling, a set of variables including the length of tree (cm-accurate), the diameter in the 1/2 of total tree height (i.e. stump height + the length of felled tree), the diameter in 0.1, 0.3, 0.5, 0.7 and 0.9 of tree height and the top diameter of each 2 meter-high log (up to 5 cm stem diameter) were measured. Then, the Artificial, Hohenadl and Natural form factors were calculated, which were then compared with the TFF. The two-way ANOVA-based comparison of means amongst the form factors in different diameter classes revealed significant differences amongst the form factors of 15 and 25 cm with other diameter classes. All form factors showed insignificant differences except for the Artificial form factor which revealed to be significantly different than the TFF. Furthermore, the real tree volume across the study site can be derived by the calculated TFF value of 0.5028. For similar sites, this study concludes the alternative form factors (Hohenadl or Natural) to be able to be used for calculating standing volume being comparable to the real volume of P. deltiodes

Investigation on growth characteristics of Poplar clones in research nursery of Boldaji station

This research was conducted in Boldaji research nursery from Chaharmahal and Bakhtiari province. At the first step, saplings of 39 clones from Alborz research nursery and 9 native clones were selected and planted on Boldaji research nursery in 1996. From these clones, 34 clones including 18 clones of Populus nigra, 11 clones of Populus x euramericana and 5 clones of Populus deltoides were established. After cutting the poplars from first and second year's nursery, three nurseries with 1/1, 1/2 and 2/3 age (right number: root age and left number: stem age) were created. Some factors such as germination percent, resistance to pest and disease, frost tolerance, height and diameter in 0.5 meter height were measured. The results showed that Populus nigra clones have most germination percent.Height and diameter growth of Populus euramericana 561.41 clone was more than other clones

Adaptation and wood production of different closed-crown poplar clones in Gorgan region

In order to select high-yielding closed-crown poplar clones a study was designed on a number of 15 selected poplar clones featuring pyramidal and closed crowns in a nursery. From each clone 75 one-year seedlings were planted within complete randomized blocks with 3×3 m spacing and three repetitions in Chaleki research station in Golestan province in March 2003. A set of main growth attributes such as growth in height and diameter at breast height (DBH) were measured for all trees. Following this, the total, annual and average rates of volume growth were calculated for each poplar clone. The results support a significant difference amongst the studied clones. Furthermore, a comparison of means showed Populus nigra 62/154 and P. nigra 56/52 clones as those showing the maximum and minimum  rates of average annual volume growth per ha with 14.60 and 1.38 m3, respectively. All in all,   P. nigra clones such as P. nigra 56/72 was shown to be the most resistant to pest attack. Based on the results, the following clones are recommended for large scale plantations: P. nigra 62/154 (average growth =14.57 m3 ha-1 y-1), P.  nigra 62/140 (average growth= 14.26 m3 ha-1 y-1), P. nigra 62/191 (average growth= 12.96 m3 ha-1 y-1), P. nigra 62/127 (average growth= 12.15 m3 ha-1 y-1), P. nigra  betulifolia (average growth=11.66 m3 ha-1 y-1), P. nigra 62/149 (average growth= 11.61 m3 ha-1 y-1) and P. trichocarpa (average growth= 10.36 m3 ha-1 y-1)

Effects of different fertilizer treatments on Poplar wood production

To study the effect of different fertilizer treatments on Populus deltoides clone 69/55, a 4-year study during 2007-2011 was conducted within two-ha site in the Fakhrabad agricultural research station in Lashte-Nesha in Guilan province. Following the site preparation, the previously-bred seedlings were planted within a randomized complete block design with three replications and five fertilization treatments. Treatments included NPK94, NPK47, NP94, NP47 as well as a control treatment. At the end of each growing season, factors including the diameter at breast height (dbh) and height growth of trees were measured. At the end of the 4-year period, the average rates of the measured parameters were analyzed. Comparison of total average growth, average annual growth and current growth was showed three distinct groups based on the amount of applied fertilizer. The first group was the treatment 1 (94 kg ha‾ ¹ NPK) produced 27.96 m³ ha‾ ¹ year‾ ¹, whereas the treatment 4 (47kg ha‾ ¹ NP) was grouped as the last one with its produced 23/62 m³ ha‾ ¹ year‾ ¹