Quality of growth substrates of post-disturbed lowland black spruce sites for black spruce (Picea mariana) seedling growth.
Martin Lavoie, David Paré, Yves Bergeron.
Black spruce (Picea mariana (Mill.) BSP) is the most important commercial
tree species in the eastern boreal forest of Canada. Only limited work has
been conducted to assess the quality of the various substrates that are found on postdisturbed
sites prone to paludification having an effect on black spruce seedling
growth. The objectives of this study were (1) to use a pot test to assess black spruce
seedling performance on substrates found at the soil surface, in the rooting zone of
undisturbed soil, at depths that become available to spruce roots after soil disturbance
by wildfire or through management; and (2) to determine the nutritional
quality of these substrates when constraints of poor drainage are artificially removed.
Black spruce growth was greatest with fibric Pleurozium in the rooting zone,
and with burned fibric Pleurozium and living Sphagnum at the soil surface. Good
seedling growth on different substrates found in the rooting zone was associated with
higher N and P foliar concentrations. Based on these results, we recommend targeted
planting of black spruce seedlings in substrates of Pleurozium origin and the
development of management techniques that promote Pleurozium schreberi.