Seedling growth and water use of boreal conifers across different temperatures and near-flooded soil conditions

Abstract

To test the hypothesis that seedling growth and water use increase with soil temperature and improved soil aeration and vary with species, we evaluated the above- and below-ground growth and water use of seedlings of four northern boreal conifer species: black spruce ( Picea mariana (Mill.) B.S.P.), white spruce ( Picea glauca (Moench) Voss), tamarack ( Larix laricina (Du Roi) K. Koch), and lodgepole pine (Pinus contorta Dougl. ex Loud.) grown under different temperature and near-flooded soil conditions. Seedlings were grown in specialized pots that maintained the water table level at either 15 cm (high water table treatment: very wet) or 30 cm (low water table treatment: moderately wet) below the soil surface, and whole-seedling transpiration was assessed. Soil temperature (5, 10, or 20 °C) was controlled with a water bath surrounding the pots. Although some species were sensitive to the high water table treatment, soil temperature was the driver of seedling growth and water use. We ranked the ability of the seedlings of the species to tolerate the cold soil conditions examined as black spruce > lodgepole pine > tamarack > white spruce. The ranking of the ability to tolerate near-flooded conditions was tamarack and lodgepole pine > black spruce > white spruce.

Positive shrub–tree interactions facilitate woody encroachment in boreal peatlands

“…thickening of root tips) to assess if interactions between trees and seedlings could have been mediated by sharing mycorrhizal partners (Wolken et al . ).…”

“…Recent changes in species abundance and distribution, hydrology and disturbance regimes in boreal ecosystems show complex interactions with climate that remain poorly understood (Wolken et al . ). Discontinuities in tree cover distribution in boreal ecosystems suggest critical transitions between states of contrasting tree density (treeless, open woodlands and forests), maintained by positive feedbacks (Scheffer et al .…”

Do plant traits explain tree seedling survival in bogs?

“…Recent tree and shrub encroachments in drained (Pellerin & Lavoie 2000;Linderholm & Leine 2004) and pristine bogs (Aberg 1992;Berg et al 2009;Kapfer et al 2011) have been attributed to warmer or drier climate, as well as to increased fire frequencies correlated with these climate conditions. Also, field experiments show that warmer and drier conditions can stimulate tree seedling survival and growth under nearly flooded conditions (Wolken et al 2011). These results suggest that tree and shrub encroachments are likely to continue in the future because climate change scenarios for the northern high latitudes indicate a further increase in average air temperature and more frequent drought events (Meehl & Tebaldi 2004).…”

“…Also, field experiments show that warmer and drier conditions can stimulate tree seedling survival and growth under nearly flooded conditions (Wolken et al . ). These results suggest that tree and shrub encroachments are likely to continue in the future because climate change scenarios for the northern high latitudes indicate a further increase in average air temperature and more frequent drought events (Meehl & Tebaldi ).…”

Coordination between water transport capacity, biomass growth, metabolic scaling and species stature in co‐occurring shrub and tree species

“…Rootstocks that produce larger fruit trees also have higher K and wider xylem vessels (Solari et al 2006;Tombesi et al 2010). Less direct evidence is shown by exponential increases in K and mass over time (Tyree et al 1998) and studies in which growth and water use generally respond in the same direction to experimental treatments (Grewal 2010;Wolken et al 2011). In this paper, our basic goal is to evaluate the relationship between biomass growth rate, G, and both K and Q.…”