One of the most successful techniques in planting trees is tree improvement in which trees with high qualities are selected for mass plantation. This study seeks to identify good properties of Eucalyptus camaldulensis through selective phases. Sixty Eucalyptus camaldulensis trees (30 ten-year-old and 30 five-year-old) were randomly selected through stratified sampling from two plantation sites in Kurdistan region, North of Iraq. The trees were examined for fiber morphology and quality parameters such as height, number of branches, diameter and straightness. In the first phase of property selection, sixteen trees with high rank in growth properties and fiber morphology were selected. In the final phase of selection, the selected trees were re-examined according to the number of properties and fiber morphology features and seven trees with the highest number of good parameters were chosen. The 7 selected trees had higher qualities in growth characteristics and fiber morphology compared with the other trees in the sample. This article reports on a selection method for E. camaldulensis trees through tree improvement techniques. The results of the study indicates that high genotype qualities were identified among both 5- and 10-year-old E. camaldulensis trees as the final selection consisted of three 5-year-old trees and four 10-year-old trees.
The River Red Gum (Eucalyptus camaldulensis) which is an indigenous tree species to Australia plays an important role in paper production industry for different countries all over the world [
E. camaldulensis has been largely planted in vast irrigated plantations in the North of Iraq. It adjusts well to different types of soil and various climatic modifications. It is generally suggested that rotation cycle for E. camaldulensis is 10 to 11 years. At this age, the average size of diameter ranges from 25 to 30 cm. 10- or 11-year- old E. camaldulensis has the highest possible wood quantity that is required by pulp market [
Eucalyptus camaldulensis were selected and screened from 10-year-old and 5-year-old tree plantations of Khabat and Pirde, located in Erbil, North of Iraq. Khabat plantation is situated on a sandy area in the West of Erbil (36˚15N, 43˚38E) with temperatures ranging between 4˚C to 41˚C, and an annual precipitation of 385 - 455 mm/year. Pirde is located on a semi flat land in the South of Erbil (35˚06N, 44˚08E) with a temperature of 9˚C- 45˚C and has annual precipitation about 319 - 402 mm/year.
There are two large E. camaldulensis plantations in Kurdistan, Iraq. In the biggest plantation site, Khabat, there were 5000 trees from which almost 2100 trees were 5-year-old and the rest are 10-year-old. In Pirde, the second biggest plantation, there were 22005 of 5-year-old and 1850 of 10-year-old trees. Each plantation is located by a river from which it is irrigated. The area of plantation was 5 ha (2.6 ha 5-year-old and 2.4 ha 10-year-old), and 4.7 ha (2.7 ha 5-year-old and 2 ha 10-year-old) for Khabat and Pirde respectively. The trees were planted at a space of 3 m × 4 m. A sample of 60 trees was selected from two E. camaldulensis plantations through stratified sampling on July 2012. From each plantation, 15 trees from each age group were selected for this study. The selected trees were named based on the age and the site. Kh is referred to Khabat plantation, and Pr is used for Pirde plantation. Numbering of 5 and 10 were used for the age it represents, and X refers to tree numbering (1-15). The same procedure was used for naming the other trees in the sample. The sample was composed of four sub-groups, and there were fifteen trees in each sub-group.
In this study, both qualitative and quantitative characteristics were used as criteria for plus tree selection. The trees in each sub-group were carefully examined and rated in quantitative properties such as height, diameter, crown height, and qualitative properties such as tree shape, branching habits (size and angle) and number of knots. Each tree was given a score ranging from 1 to 15 for a specific property, where 15 indicates the highest rank while 1 shows that the tree has the lowest quality in a specific characteristic compared with the other 14 trees in the sub-group. Each growth characteristic was evaluated separately for each tree.
Since quality of paper depends on fiber morphology characteristics, thus fiber dimensions such as fiber length, fiber diameter, cell wall thickness, lumen diameter were separated (Fiberization) and measured according to the Technical Association of Pulp and Paper Industry (TAPPI) standard T233-Su-64 [
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Wood samples were split separately into a match stick size of 2 mm in width and 10 - 20 in length, and then placed in the boiling tubes. 25 ml of distilled water was added plus 1.5 g of Sodium chlorite and 2 - 3 drops of Acetic acid for each tube. Then they were boiled in water bath placed under fume hood at 70˚C for about 24 hours. When fibers were turned into silver color, they were washed with distilled water. After washing fibers, they were separated by shaking. The macerated fiber suspensions were stained in 2 - 3 drop of 1% safranin-O for 30 minutes and placed on a slide and covered with a cover slip.
All samples were viewed under Leica Image analyzer (Leitz DMRB). A total of 30 randomly chosen fibers were measured from each slide. There are two treatments: plantation site and tree age. The qualities of Khabat trees were compared with those from Pirde. In addition, the two age groups were compared for the qualities and properties. Scores to these characteristics were added and were later ranked. After data analyzing for the growth parameter (quantitative and qualitative) and fiber morphology, the trees were ranked based on cumulative characteristics; (growth parameter + fiber morphology rank)/2.
For data analysis, independent T-test was used to analyze data, first, 5-year-old trees from (Kh) and (Pr) were compared. Then, 10-year-old trees from (Kh) and (Pr) were compared (at 5% level of probability).
Growth characteristics of the E. camaldulensis trees selected through plus tree procedures is presented in
The results show that there is no significant difference between two plantations for 5-year-old trees (p < 0.05) in growth performance characteristics, while there was a significant difference the Khabat and Pirde plantations for 10-year-old trees in growth parameters(at p < 0.05) as shown in
The best two trees were chosen based on growth, fiber morphology and cumulative scores, as summarized in
Besides growth parameters, the mean of fiber morphology characteristics of the selected trees for both age groups in the two plantations are shown in
Oluwadare and Ashimiyu [
Growth parameter | Khabat Plantation | Pirde Plantation | Napa Plantation | ||||||
---|---|---|---|---|---|---|---|---|---|
5-year-old tree | 10-year-old tree | 5-year-old | 10-year-old tree | 6-year-old tree | |||||
range | mean | range | mean | range | mean | range | mean | mean | |
Tree height (m) | 11.50 - 15.00 | 13.66 | 14.00 - 20.00 | 16.86 | 11.00 - 16.00 | 13.1 | 15.00 - 19.00 | 17.06 | 13.66 m |
DBH (cm) | 11.50 - 17.00 | 14.56 | 17.00 - 23.00 | 19.53 | 12.5 - 17.50 | 14.63 | 17.00 - 22.00 | 19.36 | 14.56 cm |
Crown height (m) | 3.50 - 7.00 | 5.15 | 4.300 - 7.30 | 5.80 | 3.50 - 5.00 | 4.12 | 5.50 - 7.50 | 6.54 | |
Clear bole (m) | 7.50 - 10.00 | 8.51 | 9.70 - 14.00 | 11.06 | 7.00 - 11.00 | 8.95 | 9.00 - 12.50 | 10.56 | |
No. of branch | 14 - 27 | 19.8 | 16 - 26 | 21.9 | 12 - 20 | 19.5 | 20 - 25 | 22.40 | |
No. of knot | 5 - 12 | 8.23 | 7 - 13 | 10.26 | 5 - 9 | 8.7 | 5 - 12 | 7.66 |
Location | Age | |||||
---|---|---|---|---|---|---|
5-year-old tree | 10-year-old tree | |||||
Growth (Qualitative and Quantitative) | Fiber Morphology | Cumulative | Growth (Qualitative and Quantitative) | Fiber Morphology | Cumulative | |
Khabat Plantation | 5Kh-6 | 5Kh-10 | 5Kh-7 | 10Kh-14 | 10Kh-3 | 10Kh-3 |
5Kh-8 | 5Kh-14 | 5Kh-8 | 10Kh-15 | 10Kh-7 | 10Kh-15 | |
Pirde Plantation | 5Pr-6 | 5Pr-3 | 5Pr-3 | 10Pr-8 | 10Pr-7 | 10Pr-7 |
5Pr-11 | 5Pr-5 | 5Pr-6 | 10Pr-12 | 10Pr-12 | 10Pr-12 |
*Kh = Khabat; Pr = Pirde.
strength properties of the unbeaten pulp of hard woods. In addition, Dharm and Tyagi [
Based on the growth, fiber morphology and cumulative scores, the best two trees were identified as summarized in
The result of this study showed that the growth performance characteristics of Eucalyptus trees from both plan tations are comparable to those results obtained by [
Fiber dimensions | Khabat Plantation | Pirde Plantation | ||
---|---|---|---|---|
Mean value | Mean value | |||
5-year-old tree | 10-year-old tree | 5-year-old | 10-year-old tree | |
Fiber length (µm) | 679.66 | 682.17 | 655.31 | 680.56 |
Fiber diameter (µm) | 10.64 | 13.41 | 13.53 | 13.31 |
lumen diameter(µm) | 5.87 | 6.80 | 6.90 | 6.53 |
Cell wall thickness(µm) | 2.38 | 3.31 | 3.32 | 3.38 |
Slenderness ratio | 63.98 | 51.05 | 48.80 | 51.27 |
Flexibility | 0.55 | 0.50 | 0.51 | 0.49 |
Runkel ratio | 0.81 | 0.97 | 1.00 | 1.00 |
Fiber dimensions | Eucalyptus camaldulensis | Leucaena lencocephala | |
---|---|---|---|
Mean Value | Mean Value | ||
Khabat Plantation | Pirde Plantation | ||
Fiber length (µm) | 679.66 | 655.31 | 652.00 |
Fiber diameter (µm) | 10.64 | 13.53 | 15.67 |
lumen diameter (µm) | 5.87 | 6.90 | 9.87 |
Cell wall thickness (µm) | 2.38 | 3.32 | 2.90 |
Slenderness ratio | 63.98 | 48.80 | 41.61 |
Flexibility | 0.55 | 0.51 | 0.63 |
Runkel ratio | 0.81 | 1.00 | 0.59 |
fiber morphology characteristics, there are no significant differences between two groups. Overall, seven trees (four from Pirde and three from Khabat) were selected as sources for propagation of Eucalyptus camaldulensis for paper production. Tree 10Pr-12 is the best source based on overall performances.
This study is part of a M.Sc project funded by Research Universiti Grant (RUGS) provided by Universiti Putra Malaysia and scholarship through Human Capacity Development Program by Ministry of Higher Education and Scientific Research/ Kurdistan Regional Government of Iraq. Authors also thank all colleagues from The
Department of Forest Management especially Dr Aktar Hossain and Wood Anatomy Laboratory of Faculty of Forestryand Institute of Tropical Forestry and Forest Products of Universiti Putra Malaysia who contributed to valuable discussion on the topics developed in this manuscript as well as for providing support, facilities, assistance and guidance in the laboratory.