The study was carried out at Padasjoki, Southern Finland, where moose (Alces alces L.) density on the winter range had been over 1.5 individuals/km2. Moose browsing intensity, expressed in terms of number of twigs eaten and biomass used, increased with stand density (biomass). Total biomass consumption (dry weight) per sample plot and per sapling. The number of bites increased, but the percentage biomass removed did not differ when stand density increased. A relatively large bite size was observed on the plots of low stand density. The quantity of food, which on average was of relatively low quality, was obviously important due to the benefit gained through reducing the search time.
The nutritive value of the browse, expressed in terms of chemical compounds indicating low food digestibility, was lower in the dense than in the sparse Scots pine stand. However, the amount of crude protein and arginine were relatively high in the dense stand. We concluded that shading affected the nutritional status of saplings on high density plots.
Although the biomass removed by moose per sapling was high for low density plots, the remaining biomass was larger than that on the high-density plots owing to the relatively large twig biomass of saplings. The number of saplings per hectare without main stem breakage increased significantly as stand density increased.
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The utilization of available food resources by the moose (Alces alces L.) was studied in a Scots pine (Pinus sylvestris L.) plantation containing an admixture of deciduous species. Rowan (Sorbus aucuparia L.) and aspen (Populus tremula L.) were highly utilized compared to pine and both silver birch (Betula pendula Roth) and downy birch (B. pubescens Ehrh.). However, they were not capable of withstanding continuous browsing by moose owing to their diminished biomass. In total, the browsing intensity (number of browsed twigs/tree) on pine and birch was about double of that on rowan and aspen.
The number of browsed twigs per tree increased as the amount of available main branches increased. The number of bites per available branch, as well as the maximum diameter of the bites, decreased as the density of the plantation increased. Silver birch was more used by moose than pubescent birch as well as planted silver birch compared with naturally regenerated trees.
Main stem breakage was especially common in winter 1988, the average height of the pine and birch trees being over two meters. The tops of broken stems were commonly utilized as food. The increase in moose density and the relatively deep snow cover evidently promoted the incidence of serious damage. The number of undamaged trees/ha was greater in dense than in sparse parts of the stand.
The PDF includes a summary in Finnish.