| Abstrakt: |
In an 18-year-old spruce (Picea abies) stand the lateral shoots of the top whorl were cut off monthly. From the harvested material two analogous samples were prepared in each case. One of the samples was dried at 70 °C in a drying cabinet (oven-dried sample), the second sample was dried at a room temperature of 18 °C (air-dried sample). The needles that fell from the shoots as a result of drying were subsequently dried at 105 °C to their absolute dry weight and analysed. During all seasons of the year air-drying lowers the 1000-needle-weight, whereas it raises the calcium and manganese level respectively. From July (or August) to May in the following year, when air-drying was applied, the potassium (and phosphorus) level in the spruce needles increased likewise. N and C content in the spruce needles differently respond to air-drying in the course of the year. Needles harvested in summer and autumn reduce their N and C content, when air-dried, while in early spring: N and C content increase in the spruce needles, when air-drying is applied. |
