Articles containing the keyword 'iänmääritys'

Clone stands of bracken fern (Pteridium aquilinum (L.) Kuhn.) wood small reed (Calamagrostis epigeios L.) and lily-of-the-valley (Convallaria majalis L.) are often partly split into two by the road, but often encountered also unilaterally on the roadside in the shape of a semicircle. The unilateral stands can be at times 20–30 m wide and they are sometimes solitary stands of the species. A method to define the age of the solitary stands of six plant species including bracken, wood small reed and lily-of-the-valley was developed in a series of earlier studies.

These stands can be used to define the time the road was built. Clones that are bound by the road unilaterally are younger than the road. If there are several unilateral clones and they are of different sizes, the road is older than the largest clone. When the road is skirted bilaterally only by clones divided by the road, it is younger than the smallest clone. When there are by the road side both unilaterally delimited clones and clones split by the road, the age of the road comes in the range of time determined by the age difference between the largest unilateral and smallest bilateral clone.

The PDF includes a summary in English.

• Oinonen, E-mail: eo@mm.unknown

Norway spruce (Picea abies (L.) Karst.) invading sites is common in Finland. The species tends to establish itself as undergrowth, and takes over when it gets space to grow. To determine whether the undergrowth is suitable as the new generation requires knowledge on the biology of spruce undergrowth. One of the issues is determining the age of the stunted trees. In this investigation, 100 undergrown spruce trees, their crown and their root systems were studied. A method was developed to determine the age of the trees.

The root system of all trees in Vaccinium sites and of stunted trees in Myrtillius sites were superficial. The root systems of older spruces were purely of adventitious origin. The longer the period of stunting growth, the younger is the root system. In addition to acropetal and general adventitious ramification there is often adventitious branching of the roots of pathological causes. Mortality among the long roots is frequent.

A stunted tree has not the same ability as a viable tree to make use of already existing branches for building assimilating surface. When comparing trees with equally large assimilating surface, a stunted tree had greater sum of roots compared to a viable tree. The root system of a stunted undergrown spruce was very superficial compared with the other trees.

The PDF includes a summary in English.

• Sirén, E-mail: gs@mm.unknown