Articles containing the keyword 'willows'

Possibilities of developing suitable willow (Salix spp.) clones for short-rotation forestry on mined peatlands in the north-western area of Finland were studied in a field experiment in which 300 willow clones were tested during 1985–87. Most of the tested clones started to grow from cuttings on limed and fertilized peat soil. Salix viminalis L. clones of southern origin had a higher leafless above ground biomass production than the well adapted control clone and the local Finnish willows, but their winter hardiness was not satisfactory. The growth habit of some southern willows was also better than that of the control clone. It was also possible to select clones with good sprouting capacity. There were few Salix myrsinifolia Calisb. clones of Finnish origin, which had better cold tolerance than all other willows tested and higher biomass production than that of the control clone. The most critical factor to be selected for this is the optimal combination of winter hardiness and biomass production. This is attempted by selecting clones on the basis of this experiment for a breeding program.

The PDF includes a summary in Finnish.

• Lumme, E-mail: il@mm.unknown
• Törmälä, E-mail: tt@mm.unknown

The solubilityof various phosphorus and potassium compounds in a sedge peat soil was studied in an incubation experiment aimed at screening potential fertilizers for the cultivation of fast-growing willows. (KPO₃)n proved not to be a source of the slow-released K regarded as most desirable for this kind of cultivation as it was hydrolysed completely in the soil during incubation. Phosphorus from easily soluble or hydrolysable compounds (superphosphate, KH₂PO₄, (KPO₃)n) was bound in the soil largely by Al and Fe and elevated the level of readily soluble P considerably, whereas rock phosphates were found to be practically unchanged after incubation and did not contribute to the readily soluble P in the soil. Apatites proved to be quite insoluble and are therefore assumed to be unsuitable as P fertilizers for fast-growing willows, which have a high nutrient demand.

The PDF includes an abstract in Finnish.

• Lumme, E-mail: il@mm.unknown
• Yli-Halla, E-mail: my@mm.unknown

Downy birch (Betula pubescens Ehrh.) trees growing on a drained peatland were cut during dormancy. The properties of the one-year old shoots produced by the stumps were measured in the autumn after one growing season. The one-year old willow shoots (a mixture of Salix phylicifolia L., S. pentandra L. and S. caprea L.) were collected from an abandoned field.

The basic density of unbarked shoots was 443 kg/m³ for birch and 346 kg/m³ for willow. The basic density of the bark was much higher than that of the wood. The effect of shoot length on the properties was small with the exception of cellular proportions. The fibre percentage increased and vessel percentage decreased with increasing shoot length.

The PDF includes a summary in Finnish.

• Bhat, E-mail: kb@mm.unknown
• Ferm, E-mail: af@mm.unknown
• Kärkkäinen, E-mail: mk@mm.unknown

A review is made into the experiences and possibilities of willow breeding, with a particular consideration of their application under Finnish conditions.

In comparison with other tree genera, Salix has many advantages in breeding. The great number of species, large genetic variation between and within species and frequent crossability offer good possibilities for improvement by hybridization. The dioecious flowering, plentiful seed production and short generation cycle are valuable properties for breeding by controlled pollination. Individuals with desirable characteristics can be easily propagated vegetatively from cuttings. The propertied stated above are also characteristic of poplars, the breeding of which has resulted in great success. Corresponding results can be therefore expected from willow breeding, which has recently been initiated in several countries.

Today willows have no practical significance for forestry in Finland. There are, however, some suitable Salix species, both indigenous and exotic, for starting material for breeding, and plenty of favourable sites for willows. Therefore, the beginning of breeding research with willows should be well justified also in Finland.

The PDF includes a summary in English.

• Malmivaara, E-mail: em@mm.unknown
• Mikola, E-mail: jm@mm.unknown
• Palmberg, E-mail: cp@mm.unknown