Silica content of 36 Brazilian tropical wood species

Microscopic analysis of 36 Brazilian Amazon wood species revealed the presence of silica in 12 species, mostly in the ray cells and a few times in the axial parenchyma and fibers. The average amount of silica in these species varied from 0.07% to 1.6% as quantified by flame atomic absorption spectroscopy (FAAS). Statistical analysis gave the following classification in terms of silica contents: very low (Diplotropis purpurea and Vatairea paraensis), medium (between 0.3% and 0.4%: Chrysophyllum lucentifolium, Couratari multiflora, Dacryodes sp., Mezilaurus itauba, Trattinnickia burserifolia, and Trattinnickia rhoifolia), high (between 0.4% and 0.7%: Astronium gracile and Couratari sp.), and very high (above 0.7%: Apuleia leiocarpa and Couratari stellata).