Survival, growth, and allometry of planted Larix occidentalis seedlings in relation to light availability

We conducted a 3-year experiment to determine how survival, growth, allometry, and specific leaf area (SLA) of planted, very shade-intolerant, western larch(larix occidentalis) seedlings respond to a wide range of light availability under natural environments. Three study sites were located within a summer-dry, cool-temperate climate near Okanagan Falls, British Columbia. Survival significantly decreased with decreasing light at the end of the third growing season on all study sites (P < 0.05). Relative growth rate in base diameter (D) and biomass components increased with increasing light(P < 0.05), whereas height (H) growth was independent of light availability from 20 to 100% full sun (P > 0.05). With decreasing light, ratio of height to base diameter significantly increased whereas shoot to root ratio and SLA did not change. Instead, the shoot to root ratio was positively correlated with total biomass. These non-plastic responses in shoot to root ratio and SLA may contribute to the very shade intolerant nature of western larch. (C) 1998 Elsevier Science B.V.