Moisture impacts on planted conifer seedling growth in boreal Québec: a water manipulation study
University of New Brunswick
In order to study the impact of water limitations on boreal forest growth, a water manipulation experiment consisting of soil water content control during growing seasons was conducted for 4 consecutive years in a humid boreal forest of Québec, Canada. Impacts of moisture of the growth on seedlings of four different commonly planted conifer species was investigated. Jack pine (Pinus banksiana Lamb.) displayed the fastest growth, followed by black spruce (Picea mariana (Mill.) BSP.), balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Monech) Voss). A linear mixed effects model was used to predict effects of soil water content (SWC) on growth. Increasing SWC in early growing season of the current year increased diameter growth for black spruce, jack pine and balsam fir and height growth for black spruce and white spruce. Higher SWC later in the growing season of the previous year increased the diameter growth for jack pine and balsam fir and height growth for black spruce and balsam fir. However, it decreased growth of small seedlings. As seedlings grow and mature, they have greater water demand but also develop water use-efficiency.