Density, some anatomical properties and natural durability of stem and branch wood of two tropical hardwood species for ground applications

Cultivation of Cedrela odorata, a valuable tropical hardwood species, is restricted by the mahogany shoot borer (Hypsipyla grandella), whose attacks reduce stem quality in forest plantations. This study investigated whether infestation rates would be reduced and growth performance improved by the intercropping of C. odorata tree seedlings with different crop rotations. The height increment achieved by C. odorata during the first two years was significantly stimulated by the intercropping of maize (Zea mays), pigeon pea (Cajanus cajan), and cassava (Manihot esculenta). Attacks of H. grandella were also considerably reduced in these treatments, compared to the control plots, while intercropping with beans and rice produced no improvement. The effect was particularly distinct when lateral competition between trees and crops was high. Accordingly stem quality was higher in the treatments featuring tall crops. Trees intercropped with C. cajan performed best in terms of height (276 cm ±93), survival (100% ±0), and quality (81% ±13.5 of trees with satisfying stem quality) after two years. We concluded that intercropping of tree seedlings which are susceptible to H. grandella with shrubby multipurpose species can improve both tree growth and timber quality and hence increase the attractiveness of such species for reforestation.

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Relationship Between Wood Colour of Seven Tropical Hardwood Species and Formaldehyde Emission of Plywood

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b11020782s419 ◽

2019 ◽

Vol 8 (2S4) ◽

pp. 520-523

Keyword(s):

Moisture Content ◽

Wood Species ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Extractive Content ◽

Tropical Wood ◽

Wood Colour ◽

Tropical Hardwood ◽

Hardwood Species ◽

Colour Appearance

There are many factors that affect the formaldehyde emission from plywood such as wood species and moisture content. As for wood species, colour appearance was found to affect significantly the formaldehyde emission. Therefore, the effects of tropical wood species with different colour on the formaldehyde emission of manufactured plywood were studied and determined by the perforator and desiccator method. Veneer of seven wood species, namely Mempisang, Kedondong, Penarahan, Keledang, Rengas, Melembu and Ludai were chosen as samples. 3-ply plywood were manufactured using urea formaldehyde as binders. The formaldehyde emission of the produced plywood was tested using perforator method (EN 120) and desiccator method (MS 1787: Part 15). Colour of the wood veneers were measured using Brightness & Colour Meter through CIE L*a*b* system. Relationship between the wood colour and formaldehyde emission were determined. The results revealed that the formaldehyde emission increased as the lightness (L*) of the wood samples increased. This may be due to higher extractive content in darker coloured wood (low lightness) that acts as formaldehyde scavenger.

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