Wood Acidity and Buffering Capacity Variation of Tampui Beras(Baccaurea macrocarpa(Miq.) Muell.Arg.)and Manggis Hutan Garcinia cornea Miq

ABSTRACT Wood acidity signifies an important factor that inflicts impact on metal corrosion and gives effect on adhesive bonding quality. Wood acidity varies not only between species, but also at different parts in the same tree. This paper studies the wood pH and buffering capacity at various positions in the same tree of two potential species from Riau. Those wood species are locally known as tampui beras (Baccaurea macrocarpa (Miq.) Muell. Arg.) and manggis hutan (Garcinia cornea Miq.). The pH was determined using pH meter on the liquid of hot-water-extracted sawdust of the corresponding wood, while buffering capacity was measured by acid and base titration. The result shows that in average, acidity of tampui beras wood (5.2) is stronger than that of manggis hutan (6.3). Both wood species are classified as acid wood with pH less than 7. With respect to the tree height, sample taken from bottom part has the lowest pH value, while based on lateral position at the stem, progressing from the bark in depth to the pith the sapwood is higher in pH value than the heartwood and transition area. In every wood sample tested, acid buffer capacity is higher than base capacity.