engleski

Selection of Chinese Willow (Salix matsudana) and White Willow (S. alba) Clones and Their Hybrids Suitable for Biomass Production

In 2002, an experimental culture of short rotation crops for biomass production was established on an abandoned farmland. It includes 25 clones of arborescent willows grown from open pollinated chinese willow (Salix matsudana), the hybrids between chinese and white willow (S. matsudana x S. alba) x unknown, the back crosses of S. matsudana x S. alba with chinese willow, the hybrids between chinese and white willow (S. matsudana x S.alba), together with a few white willow clones (Salix alba), and one trispecies hybrid (Salix alba x S. fragilis x S. caprea). At the age 2/3 (2-year-old shoots and 3-year-old stump) first measurements of the given culture were conducted. Measures were taken for all the plants at their breast height (1.30 m from the ground), and fresh biomass of the wooden shoots was measured on a 10% sample of each clone. Samples of 1kg of biomass of all the clones were oven-dried at 105 ˚ C to constant weight. That way, data were obtained on the moisture content in wood biomass. Data reporting on fresh biomass of the observed clones were reduced according to the respective moisture content, enabling biomass estimation of a dry sample. Nonlinear regression analysis run for dry biomass and diameter at breast height of the sampled plants shows strong relationship between those two traits. By using the obtained regresssion models together with the previously measured diameters at breast height, estimation was made of dry biomass of each individual plant in the experimental culture. Biomass production per hectare was estimated according to dry biomass of a mean ramet, planting density and survival rate at the observed age. Average dry biomass output reached 5.6 t/ha, however, a significant variation between the tested clones is clearly visible. The largest production was achieved by the clones ‘ V 580’ (10.5 t/ha), ‘ V 578’ (9.9 t/ha), and ‘ V 575’ (8.8 t/ha), selected in the openl pollinated family of the clone S. matsudana ‘ Tsinan’ , as well as by the clone ‘ V 572’ (9.9 t/ha) grown from open pollination of the clone S. matsudana × S. alba ‘ Tangoio’ . The white willow clones, as well as the clones grown by means of back crossing between chinese willow and the hybrids of chinese and white willow, proved to yield below the average output. The poorest biomass production was recorded for the trispecies hybrid Salix alba × S. fragilis × S. caprea ‘ V 221’ which was 1.7 t/ha. Among the hybrid clones S. matsudana × S. alba, only the clone ‘ Tangolo’ yielded the largest ouput with 8.6 t/ha. Average survival of the tested clones was 86 %, ranging from 53% (clone ‘ V 221’ ) to 100% (clones ‘ V 580’ i ‘ V 576’ ). The obtained results have shown high production of dry biomass by the arborescent willow clones grown from open pollinated maternal trees of the chinese willow (S. matsudana). The arborescent willow clones were reported to have a significant potential for biomass production in short rotations and are to be recognized as useful form of providing energy supplies in similar habitats.

short rotation crops; bioenergy

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