Effets du drainage sur la croissance et le statut nutritif d'un peuplement d'epinette noire de structure inequienne: resultats de 10 ans | Effects of drainage on the growth and nutritional status of an uneven-aged black spruce stand: results of 10 years
2005
Prevost, M. | Dumais, D. | Plamondon, A.P.
We present the 10-year results of a forest drainage experiment conducted in a pre-mature uneven-aged black spruce (Picea mariana [Mill.] BSP) stand, in Bas-Saint-Laurent, Quebec, Canada. The set up included 20, 30, 40, 50 and 60 m ditch spacings, and the data were pooled in three diameter classes, less than or equal to 4 cm (small stems), 6-10 cm (medium-size stems) and greater than or equal to 12 cm (large stems), in order to take into account stand structure in the analysis. The diameter growth of large stems (dominant cover, height approximately 8-12 m) was not improved by drainage. Medium-size stems (intermediate story, approximately 4-8 m) showed a better growth at a 5-10 m distance from the ditches, while small stems (understory approximately 1-4 m) reacted well to drainage, proportionally to ditch closeness. Generally, growth and gain attributable to drainage increased with the live crown ratio, from one third of the total tree height. We did not detect any effect of drainage or distance from the nearest ditch on the nutrient content of the current year foliage of the large stems. For small stems, even the individuals located at 25-30 m from the ditches showed a growth increase compared to the control, although the understory did not benefit from full light conditions. Results suggest that drainage aiming at correcting watering-up following harvesting could permit a rapid growth increase of advance growth.
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