article id 5358,
Cytopathological and external observations on red spruce (Picea rubens Sarg.) needles damaged in winter in Vermont.
article id 5358.
Full text in PDF
The red spruce (Picea rubens sarg.) population in the Green Mountains in Vermont has showed foliar deterioration that has not been fully explained. The most characteristic needle injuries of the sensitive trees appear in late winter when the first-year needles turn brown. The cytopathological and external observations on the symptoms support the interpretation that winter stress triggers the damage. It is possible that some anthropogenic stress factors (components of acid deposition or ozone) and/or natural factors predispose the trees to the damage.
The PDF includes an abstract in Finnish.
Category: Research article
article id 537,
category Research article
Crown condition as an indicator of the incidence of root rot caused by Heterobasidion annosum in Scots pine stands.
article id 537.
Full text in PDF
Trees in three Scots pine stands seriously infected by Heterobasidion annosum were classified according to their crown condition into four classes, from healthy to dead trees. After cutting the stands, the classification was compared with the symptoms of annosum root rot on stump surfaces (pitched area) and with the extension of decay in the roots of excavated stumps. When dead trees were included, the average crown condition on the survey plots correlated with disease incidence. Without dead trees the correlation was not significant. Slightly infected trees could not be distinguished from healthy trees on the basis of crown condition. It was concluded that only the proportion of dead and dying trees in a stand is a reliable indication of the disease incidence for making decisions about the future management.