| The relationship between cutting frequency, reserve carbohydrates, and biomass production was examined in Gliricidia sepium and Leucaena leucocephala in the seasonally dry climate of Ibadan, Nigeria. In the most frequently cut treatment, gliricidia was cut twelve times in 11 months and leucaena was cut eleven times in ten months, at 25 cm above ground level. Sample cores from large roots and lower stems were analyzed for sugars, starch, and total reserve carbohydrates (sugar + starch) using the perchloric acid/anthrone method.;Frequent cutting progressively decreased starch and total reserve carbohydrates. In frequently cut trees, on the last sampling date, starch concentrations in leucaena stems and roots, and gliricidia stems were generally less than 10% of control values. Starch in gliricidia roots was approximately 60% of the control value. In frequently cut trees, sugar in roots and stems were maintained at, or above, control levels throughout the study period. Mortality occurred only in leucaena, after starch in stems and roots had decreased to 2 mg g;During shoot regrowth, starch levels decreased first in stems and, after additional cuts, in roots. Dry-season cuts had little effect on reserve carbohydrates in gliricidia, but reduced stem starch in leucaena.;No starch replenishment occurred during the six weeks after cutting. Following a cut at the end of the dry season, starch reserves in leucaena were substantially restored after three months. In gliricidia, stem starch after seven months was still 50% of the control; root starch was little affected by this cut.;Frequent cutting reduced dry matter production. Generally, there were strong positive correlations between dry matter production, and stem and root starch levels, suggesting that reduced carbohydrate levels contributed to lower biomass production.;A second study evaluated seasonal carbohydrate trends in uncut, 12-year-old trees, including gliricidia, leucaena, Dactyladenia barteri, Pterocarpus soyauxii, and Senna siamea. Sugar and total reserve carbohydrates were highest during the dry season. Starch had two maxima: early in the dry season and early in the wet season. Lowest starch and total reserve carbohydrate concentrations occurred 2... |
