Construction with coconut palms
I am getting questions from the field about construction with coconut palms in the Philippines:
How old can a tree be before we can harvest the leaves for making walls and roofs ? How easy is it to grow in salt damaged soil? Can you use the old trunks for planked wood? etc etc
Nice interesting question about the construction capacity of Coconut trees
Thanks in advance as always for your help Paul
On the fronds I suggest as soon as reaching maturity and that they can be dried and "woven" like a cadjan you could use. I have found no specs but will look in the next days (in fact i am in Manila next week). A caution is that for example in Sri lanka cadjan (basically coconut frond) is not supposed to be used in municipal areas due to vector / malarial risk (there is a relevant bylaw but I do not remember it) ... just a caution .
On the timber I can assist a bit more with an "edited" extract from a report I wrote for donor last year in Sri Lanka that may give some guidance. This however was for more permanent construction than emergency construction so could be relaxed accordingly.
"............................ Alternative Species, Grading and Materials for Timber Applications Alternative species are being sought but even these options are limited and expensive. There are restrictions on the milling of coconut as plantation crop, however, after 60 years it is considered to have reached the end of its useful economic life and can be milled for timber - though only generally the bottom one third to one half of the stem is usable structurally. Substantial quantities of coconut timbers were used structurally after the tsunami, though it is not preferred by the beneficiaries.
The FAO refers to the traditional use of coconut in Sri Lanka: “………In countries where processing of coconut wood was traditional (Sri Lanka, India, Zanzibar), coconut wood has been used as rafters and beams for roofs of buildings, window and door frames, and boat building. In Sri Lanka, coconut wood rafters …. ridge plates (ridge rafters) … are also made when old, large-diameter coconut palms are cut down……. The price of coconut wood rafters is about 30% of the price of conventional wood used for roof structures. There are many houses and buildings in Sri Lanka with roof structures built of coconut wood that are still in use after 100 years. These are special cases where the bottom one third of the stem of very old trees have been used without any treatment. In most cases, particularly when the middle third of the stem is used for roof structure, a preservative such as ‘solignum’ is applied. In some cases, used engine oil is used as a preservative to reduce cost……..”
In local studies in 1997, anticipating the need for alternative timbers it was suggested that alternative species might include Coconut (Cocos Nucifera); Cypress (Cupressus Macrocarpa); Eucalyptus species (Eucaluptus Grandis, Eucalyptus Pilularis, Eucalyptus Robusta, Eucalyptus Microcorys, Eucalyptus Citradora, Eucalyptus Globulus); Ginisapu (Michelia Champaca) and others. A number of these are considered in the earlier paragraphs above.
The State Timber Corporation (STC) of Sri Lanka currently propose Saligna (Eucalyptus Saligna) as an alternative to Jak, Palu, Eta Thimbiri, Dun. for structural application timbers (beams, rafters, ridge plates, wall plates and purlins / reepers) and Microcoris Grandis as an alternative to Jak, Teak, Milla, Keta Kela, Path Kela, Koon for window and door frames.
It should ... (more)
Protrade did a technical manual on Coconut Palm Stem Processing. Among other things it points out that the density of the wood from young trees is so low that they do not make good construction material. Old trees have the best wood. I attach the manual here.
The FAO did a forestry paper (no 57) on coconut wood processing (attached)
They also did a paper on coconut production (confusingly also No 57 in that series - I have not been able to locate an electronic copy of that).
There are simply thousands of papers and books on coconuts. In 1985 the Philippine Council for Agriculture and Resources Research and Development published Technical Bulletin 60, a 93 page booklet on "Philippines Recommends for Coconut Timber Utilization"
The Council is at: http://www.pcaarrd.dost.gov.ph/
However Coconut R&D is now undertaken by the Philippines Coconut Authority's (http://www.pca.da.gov.ph/) Research and Development Extension Branch which has an ask our expert forum at http://www.pca.da.gov.ph/coconutrde/index.php/forum.
Coconut researchers in the Philippines might be best placed to answer questions about coconut palms.
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