Browsing by Author "Hamza, Kiko Francis Silas"

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Variation of heartwood proportion and leachability in plantation grown teciona crandis l. f.
(Sokoine University of Agriculture, 1988) Hamza, Kiko Francis Silas
The age at which heartwood starts to form in Tectona grandis L.f., the relationship between some stem parameters and heartwood proportion, heartwood anatomy and chemical aspects were studied. Sample trees for determination of age at which heartwood starts to form were obtained from 5, 6, 7, 8, 9 and 10 year old stands. For the determination of heartwood proportion and its variation with age, dbh, total tree height and height in the stem, heartwood acidity and leachability,sample trees from 7, 11, 16, 21 and 25 year old stands and from 32 and 50 year old trial plots were used. It was found that heartwood started to form when the trees are between 7 to 9 years old. It was also observed chat : heartwood proportion increased asymptotically with increase in age; heartwood proportion increased asymptotically with increase in dbh; heartwood proportion increased asymptotically with increase in total tree height for 11, 21 and 25 year old trees; heartwood proportion increased with increase in dbh and total tree height considered together; heartwood proportion decreased with increase in height in the stem; An average heartwood pH of 5.5 was obtained from 25 year old trees. Within a period of 30, 60, 90 and 120 days heartwood sample pieces soaked in cold water lost 0.05%, 0.11%, 0.19% and 0.21% by weight respectively. A loss of 0.07%, 0.16%, 0.27% and 0.5% by weight occurred for hot water leaching for 24, 43, 72 and 96 hours respectively. These losses were not significant at 95% confidence level.