Nor Aini Ab. Shukor , Paridah Md. Tahir, Mohd. Faisal Jaafar and Zainal Abidin Ismail

2. Evaluation of Selected Physical and Mechanical Properties of Multiple Leader Acacia crassicarpa A.Cunn.Ex.Benth and Acacia mangium Willd. Nor Aini Ab. Shukor, Paridah Md. Tahir, Mohd. Faisal Jaafar and Zainal Abidin Ismail INTROP/Faculty of Forestry Universiti Putra Malaysia 43400 Serdang, Selangor, MALAYSIA. Tel:6-03-89467186 anishukor@yahoo.com

3. INTRODUCTION • Forest tree plantation in tropics - exotic species. e.g. pines and acacias. • Species trial results - useful information on: (a) performance (b) adaptability (c) species-site interaction…BUT • Required research to understand, physiology, genetic and wood properties. • Extent of Acacia plantation in Asia – review - Turnbull (1998);

4. Many national and international provenance trials of A. mangium and A. crassicarpa conducted – different regions. e.g. China,Indonesia, Malaysia, Thailand, and Vietnam. • Results of introductions and genetic improvement especially in Malaysia and Thailand revealed some impediments and limitations in : • (a) growth - incidence of heartrot • (b) Tree form - develop multiple trunk and epicormic • branching/multiple leader (ML) formation • ML – most limiting factor for log production of • desirable size – 15 years rotation • ML – having more than 1 leader/stem from the base

5. ML class 1 ML class 2 ML class 3 ML class 4 Figure 1: Various classes of ML formation

6. Actual factors causing and variation of ML - not known. It may be due to genetics and site environmental conditions (Srivastava,1993). Others related it to: (a) cultural practices (b) genetic variation within genotypes and families Standard sivilcultural practice in Malaysia of ML - singling i.e. retaining one stem per tree and cutting the rest. Done as early as 4 - 6 months after out planting - before formation of heartwood.

7. Formation ofML is undesirable – lower the quality of timber – currently no report on quality of wood properties of ML sources. Single wood usually purchase higher value - for sawn timber (Kong, 1998).

8. To evaluate selected mechanical and physical properties of the multiple leadered trees from different genotypes of Acacia crassicarpa and Acacia mangium. OBJECTIVES

9. Wood specimens for 5 yr-old of 2 species; i) A. mangium ii) A. crassicarpa involving : 1. Provenances from 2 regions i.e a) 4 from Queensland (QLD) i) Claudie River, ii) Chillie Beach, iii) Captain Billy road, iv) Russel Gap & CK b) 3 from Papua New Guinea (PNG) i) Bensbach WP, ii) Bimadebu WP iii) SW of Boset WP AND 2. ML classes i.e a) ML2 (with two leaders) b) ML3 (with more than two leaders). MATERIALS AND METHODS Seeds of A. crassicarpa Seeds of A. mangium

10. Bimadebum WP • Bensbach WP • SW of Boset WP PNG • Chillie Beach • Captain Billy road • Claudie River • Russel Gap & CK QLD Figure 2 : Selected provenances used in this study.

11. Table 1: Provenances (genotypes) of A. crassicarpa and A. mangium A. crassicarpa A. mangium Note * - Provenance Russel Gap & CK was excluded due insufficient sample size

12. With two leaders With more than two leaders Two leaders Three leaders Four leaders ML 2 ML 3 Figure 3: Wood specimens obtained from two ML classes.

13. Established at the How Swee Estate, Kuala Lipis, Pahang (Lat: 40 20.5’N, Long: 1010 55.5’E , Alt: 91.50 m asl.) Mean annual temperature: 270C. Annual rainfall: 2,211 mm. Soil description: Deep, brownish yellow - yellowish brown fine sandy loam , weak to moderate medium - fine sub angular blocky structures. STUDY LOCATION

14. FIELD TRIAL A trial of A. mangium A trial of A. crassicarpa Figure 4: Location of the Study Site in Kuala Lipis, Pahang where the specimens were taken

15. The samples tested according to BS373:1957-Testing of Small Clear Specimen of Timber for : i) Physical- specific gravity (SG), radial and tangential shrinkages. ii) Mechanical - modulus of elasticity (MOE) and modulus of rupture (MOR) properties. Data - subjected toANOVAof the different sources using SAS version 6.12 software. Mean values -compared and separated by Duncan’s New Multiple Range Test. Schematic diagram of sample used in this study. Sample tested for static bending

16. RESULTS AND DISCUSSIONS

17. Table 2: Summary of physical and mechanical properties of A. crassicarpa and A. mangium * Significant at p<0.05. • A. crassicarpa: significant differences between ML • A. mangium: significant differences between provenance ns - not significant

18. Physical Mechanical Figure 5: Mean Value of SG, Radial and Tangential Shrinkages, MOE and MOR between ML2 and ML3 of A. crassicarpa a a b b a b a a b b ML2 ML3 ML2 ML3

19. Significant differences ofphysical and mechanical propertiesbetween MLclassesBUTnot betweenprovenances ML2produced higher mean values in terms of specific gravity, MOE and MOR compared to ML3 because ML2 produced bigger diameter stem size – infering larger heartwood portion, higher amount of wood substance to cell cavity and thus higherspecific gravity (SG) SG is closely related to wood mechanical properties (Zhang, 1997). A. crassicarpa

20. However, ML2 showed lower shrinkage (radial and tangential) than ML3 – thus growthstress is more pronounced in ML 3 compared to ML 2. ML 3 experience more stress as the result of more injuries during the singling operation compared to ML 2. (assumption: When no. of leaders removed increased, injuries increased)

21. Physical Mechanical Figure 6: Specific Gravity, Radial and Tangential Shrinkages, MOE and MOR of different Provenances of A. mangium.

22. Significant differences ofphysical and mechanicalproperties betweenprovenances classes BUTnot betweenML classes Provenance from Bensbach WP perform the bestwhile SW of Boset WP- poorest in terms of physical and mechanical properties Differentprovenances/genotypesexpressed differentcapabilitiesin terms of growth and physiological function including wood properties. A. mangium

23. Table 3 : Physical properties of important plantation species Note: MLa - Multiple leader (Captain Billy Road) ML2 - Multiple leader with 2 leaders MLb - Multiple leader (Bensbach WP) ML3 - Multiple leader with > 2 leaders MLc - Multiple leader (SW of Boset WP)

24. Table 4 : Mechanical properties of important plantation species Note: MLa - Multiple leader (Captain Billy Road) ML2 - Multiple leader with 2 leaders MLb - Multiple leader (Bensbach WP) ML3 - Multiple leader with > 2 leaders MLc - Multiple leader (SW of Boset WP)

25. Different species responded differently on the physical & mechanical properties based on ML and provenances differences. Strength is associated with ML classes i.e. the lesser the number of stems, the better the physical and mechanical properties. Based on the MOE values obtained, it is assumed that such wood sources would have similar utilization to selected important plantation species such as Hevea. CONCLUSIONS

26. THE END THANK YOU..