COCONUT PALM STEM

Cross section of coconut palm stem with density zones

Source:Sulc, 1984, 1

Only when palms are over 60 years of age (that is, when the copra yield declines, and they are of less interest to the farmer), is enough “wood” built up and therefore of use to the sawmiller. This implies that there is no conflict between the use of the palm for its primary production (oil and fat) and the later stem use for timber. On the contrary: the use of the timber generates a windfall profit to the farmer.

It also implies that only stems of tall varieties can be used for timber, not those of dwarf varieties.
The percentage of the various density groups per stem depends on variety, site, age, sweep of palm, human impact (harvesting step, Figure 4), and the extent of fungus and insect damage.

Harvesting steps in coconut palm stem

With 80-year-old palms of the San Ramon Tall variety in Zamboanga a distribution of

High density	40 – 50 %
Medium density	20 – 30 %
Low density	20 – 30 %

was observed.

All mechanical properties which define the use of a timber are closely related to its density (weight/volume at given moisture content). This inhomogeneity influences the methods of processing as well as the uses for the coconut palm stem. Sulc (1983, 3) has assessed the mechanical properties for the different density groups (Table 2) of 80-year-old coconut palm stems from Mindanao, Philippines.

Table 2: Mechanical properties of coconut wood, 12 % mc

Basic density	(g/cm3)	0.25 – 0.39	0.4 – 0.59	>0.6
Strength	(MPa)
Modulus of elasticity		3633	7116	11414
Modulus of rupture		33	63	104
Compression parallel to grain		19	38	57
Shear		n.a.	8	13

Source: Sulc, 1983, 3

Sources FAO Report, Assessed on 21 February 2016