註釋 To experiment silvicultural treatments aimed at increasing productivity of northern hardwood stands, a thinning experiment was established in 2009 in even-aged, 35-year-old sugar maple (Acer saccharum Marsh.) stands in Estrie (Quebec, Canada). In addition to an untreated control, the design included two thinning intensities (moderate and high), with or without the application of a fertilizing soil amendment consisting of lime mud and paper biosolids broadcast mechanically from the skid trails. Soil and sugar maple foliage analyses before the start of the experiment indicated calcium (Ca) and potassium (K) deficiencies. After 5 years, the treatments indicated that: 1) fertilization increased Ca availability, soil base saturation and pH, and reduced the soil exchange capacity of the forest floor and of the first 10 centimetres of mineral soil; Ca was no longer deficient; 2) fertilization considerably modified the nutritional status of sugar maple and yellow birch (Betula alleghaniensis Britt.), mainly by increasing foliar Ca and phosphorus (P); 3) without fertilization, the nutritional status of the 3 tree species studied was slightly or not modified by the two thinning treatments. However, thinning caused a dilution effect of the foliage nutrients for yellow birch and American beech (Fagus grandifolia Ehrh.); 4) the thinning treatments caused basal area growth of individual trees to increase for the 3 tree species studied; 5) for sugar maple, fertilization of the thinned forest plots further increased individual tree basal area growth compared to thinning only. Both thinning and fertilizer application had positive short-term effects in young northern hardwood stands. However, further monitoring will be needed to confirm the longer-term effect of fertilization at the stand scale. 