Articles containing the keyword 'runkomuoto'

Finnish tree species have adapted differently to heavy snow loads that occur especially in fell areas in Kuusamo and Salla as well as Maanselkä area in Sotkamo and Rautavaara in Northern Finland. Norway spruce (Picea abies Karst. L) is adapted better than Scots pine (Pinus sylvestris L.). The aim of this study was to investigate how crown and stem form of Norway spruce in the snow damage area of Maanselkä area differ from other areas in the same region.  

Relatively broad crown at the base of the stem, quickly tapering crown and narrow and even upper crown were typical for trees growing in the snow damaged areas. The higher the altitude is, the stronger tapering the crown is. The tapering begins usually in a height of 4-5 meters. Even the stem diameter begins to taper strongly at this height. In the areas where heavy snow does not cause snow damage, top of crown is broader. Also, in the snow damage areas the damaged trees seem to have broader crown shape than the trees with little damages.  

Height of the trees decreases in the snow damage areas compared to forests in lower altitudes, which can be caused both by wind and snow load. 

The article includes a German summary. 

• Mikola, E-mail: pm@mm.unknown

The stem form influences the value and volume of the stem. Sample trees in homogenous mixed stand of Scots pine (Pinus sylvestris L.) and Betula sp. were measured to define the stem form of the trees, and to develop research methods. The height of butt swelling and the turning point of taper curve varies greatly. In Scots pine and Betula sp. it was typically between the 2/10 and 3/10 height of the tree. Consequently, the theoretical normal curves describing stem form, where the turning point of taper curve is situated under the breast height diameter, are not entirely generally applicable. There was a correlation between the base curve and the form of actual taper curve of the stem. The form of the top of the stem depends on the structure and dimensions of the crown. The most reliable measuring point to define taper curve would be a diameter that is above butt swelling, near the turning point of the taper curve. Length of the crown can be used to deduce the form of the top of the stem. According to the study, the volume tables could be based on diameter on breast height, slenderness of the stem (D_0,25h:h) and length of the crown. Age of the tree and position in the stand influence stem form, but the forest site type seemed not to have clear effect on the stem form.

The PDF includes a summary in German.

• Lappi-Seppälä, E-mail: ml@mm.unknown

Crown class is useful tool both in forest management and forest mensuration. The study presents a detailed crown classification for Scots pine (Pinus sylvestris L.). It was used to classify the sample trees prior detailed measurements of the crown and stem form. The stem form of a tree was dependent on which canopy layer it belonged. This relation was detected on both Vaccinium and Calluna site type forests. In addition, the stem tapers faster in poorer forest site types compared to better sites. The shorter the self-pruned part of the stem is, the faster the stem tapers. According to the study, the stems of stunted trees taper faster than trees of other crown classes. Also the age group affects stem form.

The PDF includes a summary in German.

• Lakari, E-mail: ol@mm.unknown