Eero Pelkonen

Männyn ja kuusen taimien kyvystä sietää tulvaa vuoden eri aikoina

Pelkonen E. Männyn ja kuusen taimien kyvystä sietää tulvaa vuoden eri aikoina.

Tiivistelmä

The root systems of rooted Scots pine and Norway spruce seedlings were kept in slow-flowing or stagnant ditch water for periods of varying length during different seasons. In the snowless period, the "flood" lasted from one week to three months. The seedlings were planted immediately after they hade been removed from water. If the treatment was started early in the spring before the beginning of root activity, both pine and spruce seedlings survived even if the treatment lasted until beginning of August. However, slight negative effects in growth and general development were observed. During late summer and autumn, pine and spruce seedlings appeared to suffer much more of temporary "flooding"" treatments than in spring and early summer. A treatment period of 2—3 weeks often was detrimental to a seedling. Norway spruce seedlings were less resistent in this respect than Scots pine seedlings. In November when soil temperature is approaching 0°C in Southern Finland, artificial flooding still caused damage to spruce seedlings. Part of the seedlings included in the experiments were kept in water throughout the winter. The effect of the treatment on the seedlings depended on the degree of ice formation in the water reservoir. If only a thin ice cover was formed (slow-flowing water), leaving major part of the root system in liquid water, both pine and spruce seedlings survived quite well; only a slight decrease in growth was observed during the following growth period. Instead, if the whole root system was surrounded by solid ice (stagnant water), more negative influences were observed, especially in the case of Scots pine. Also in the case of Norway spruce, a considerable decrease in growth during the next growing season was detected. Analogous experi-mets with larger individuals of the same two species (Pelkonen 1975, 1976 have shown corresponding results. "

Vastaanotettu 31.10.2017 Julkaistu 1.1.1979

Katselukerrat 1208

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