Restoration of a deciduous woodland in Western Norway formerly used for fodder production: effects on tree canopy and field layer

Abstract

The rich deciduous woodland at Loi, Luster, Inner Sogn, 61° 20′ N., was traditionally used for fodder production from both tree and field layer. After more than nearly 40 years of disuse and secondary forest succession, experimental efforts were made to restore the traditional agricultural ‘meadow woodland’. Following a detailed preliminary registration of the vegetation the following measures were taken:

• 1. The understory tree layer, mainly Alnus incana was removed.

• 2. The old Ulmus glabra pollards were pruned back to traditional shape, as were some tall shurbs of Corylus avellana.

• 3. The field layer was mown once or twice yearly.

The main results are:

• 1. The pollarded elms have developed bundles of new twigs at the pruning points and are in good condition.

• 2. After an expansion of tall, nitrophilic herbs, e.g. Urtica dioica, Impatiens noli-tangere and Rubus idaeus, low and medium sized herbs and grasses have increased both in numbers, frequency and abundance. Helio- and thermophilic forest margin species are also more prominent. The moss layer has also become more dense and varied.

• 3. The average number of species in permanent plots has nearly doubled.

The status of the vegetation is still far from that of the traditional ‘agricultural woodland’. So far the experiment shows that it is possible to restore the tree layer completely, and the development of the field layer points toward a herb rich meadow resembling the vegetation found under traditional management.