Studies of root competition in a poor pine forest by supply of labelled nitrogen and phosphorus
Björkman, Erik; Lundeberg, Göran
The phenomenon known as root competition in lichen pine forests has been studied by means of applying ammoniurn sulphate and potassium phosphate labelled with N15 and P32 respectively to a plot with a seed tree (Pinus sylvestris) in the centre. Under the tree there was a typical competition zone. Both Calluna vulgaris and Vaccinium vitis idaea proved to be at least as efficient absorbers of nutrients as the pine plants in the natural regeneration under the seed tree. In the vegetation inmediately outside the fertilized area only traces of the added nutrients could be found. An analysis of the root distribution revealed that the suppressed pine plants in the competition zone had their roots spread chiefly in the deeper layers while the roots system of the older tree dominated the upper layers where the supply of nutrients available to vegetation is largest. At a distance of 5-7 m from the tree, where its competition began to decrease, the small plants were found to have a considerably more superficial root system than what thye had nearer to the tree.
Pinus silvestris; roots; nitrogen; phosphorus; root competition
Studia Forestalia Suecica
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