Dégagement chimique ou manuel de plantations d'épinette noire? Étude de cas dans le domaine de la sapinière à bouleau blanc au Québec

Abstract

This study aimed at comparing manual and chemical release treatments in black spruce plantations within the balsam fir – white birch ecosystems located in the Lower-Saint-Lawrence and inland Gaspe region of Quebec. Three experimental sites characterized by competition dominated by red raspberry (Rubus idaeus) were selected for the study. On each site, a completely randomized block design with seven repetitions was used. Each block was composed of four plots, each representing a vegetation treatment: a manual release, a manual release to be repeated two years later, a chemical release using Vision® (Monsanto Canada), and no treatment on a control plot. The effects of treatment on spruce growth were assessed 1, 2, and 5 years after treatment. The spruce seedlings benefited from the release treatments. After five years, spruce diameter was 25.2 to 42.9% superior, height was 12.5 to 24.8% superior and the mean volume index was 89.3 to 168.6% superior to seedlings on control plots. Moreover, growth profiles ov...