Sowing Rates in Forest Tree Seedling Production

1986

S. 1-7

16 Lit. Ang.

Unselbständiges Werk

200096979

Criteria to adopt when determining sowing rates in forest nursery, in order to produce the highest number of seedlings at the lowest costs, are illustrated. For seedbed sowing, criteria are suggested for calculating the seed amount/sq.m to be distribued, the seedbed area required, and seed total needs. As concerns direct sowing, two procedures are reported: by tentative and by direct calculation. By tentative calculation, the seed number per container - on which both the number of containers to be sown and seed total needs depend - is determined by a tentative approach, choosing the sowing rate able to minimize the total amount of the three cost factors considered, i.e. seed cost, cost for preparing and sowing the containers, thinning cost. By direct calculation, the natality coefficient (namely the predicted percent of containers where on seed at least will germinate) is firstly determined. Keeping into account that such coefficient is a function of seed viability and of the number of seeds sown per container, this last value can be mathematically calculated by exponential equation.