PHENOLIC-COMPOUNDS IN NATURAL SOLUTIONS OF A CONIFEROUS FOREST

Phenolic compounds have been identified previously as potentially resp onsible for allelopathic interferences in spruce forest at high altitu de. They have now been analyzed in canopy leachates, snow, and soil so lutions collected from the three layers of the podsolic soil: OA, E, a nd B. Leachates were characterized by high tanning capacity and by p-h ydroxyacetophenone (found at 10(-6) M) also detected as the major (10( -7) M) monomeric compound in snow. At least 10 phenolic monomers, incl uding vanillic, p-hydroxybenzoic, and protocatechuic acids were identi fied in capillary waters extracted from the OA layer with their sum re aching 2 x 10(-6) M. These monomers were only a small part (1%) of the total phenolics. In soil solutions, significant decreases in phenolic concentrations with depth were observed between the E and B layers, w ith qualitative modifications of the phenolic pattern. Spruce leachate s and soil solutions exhibited high temporal variability, resulting in transitory allelopathic potential towards both aerial and subterranea n parts of spruce seedlings. The occurrence of various and soluble phe nolic compounds in the whole forest system, including p-hydroxyacetoph enone, which persist from green needles to soil solutions, suggests th at they could be involved in complex and interactive processes occurri ng during organic matter accumulation on the coniferous forest floor.