[The quality of environment and vitality of pine in Latvia]
2002
Spalte, E. (Latvian State Forestry Research Inst. "Silava", Salaspils Latvia))
In Latvia, vitality of pines (P.silvestris L.) is affected mostly by the precipitated environmental pollutants transported from the other countries and by the rising air temperatures in winter as a consequence of global warming brought about by the so-called grennhouse effect. The years 1994-1999 saw increases in precipitation and in nitrates dissolved in the precipitation, and a reduction in ammonium and sulphate concentrations and pH values. The width of tree rings is a significant indicator of vitality of tree stands. In pines, the width of the ring is greatly affected by the mean winter air temperature, especially in January and March. The latter accounts for 56.6% of variations in the width of the tree rings. Warm winters favour vitality of pine stands and augmentation of the width of the ring. Lower soil pollution and increasing air temperatures better vitality of tree stands. Warm winters and wet summers are also favourable for wintering and reproduction of pests and spreading of tree deseases. All things considered, more attention should be paid to the elaboration and timely implementation of forest-protective measures.
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