WOODY ROOT-SYSTEM DEVELOPMENT OF WHITE SPRUCE LAYERINGS IN A TUNDRA ENVIRONMENT

The root system of individual layerings excavated in an 8 m diameter, approximately 500-year-old clonal island of white spruce (Picea glauca [Moench] Voss) on the forest-tundra near Churchill, Manitoba, consist ed of roots in accumulating litter and peat within the island and one or two main roots up to 12.25 m long extending into the surrounding li chen-heath. One of the latter, recently dead, was 280 Fears old with a n initial extension rate similar to roots of the early 1900s. Needle m ass, wood surface area, sapwood volume and current annual mass of wood were measured as estimates of carbon allocation in one layering. Belo w ground, wood surface area and sapwood volume constituted 74% and 84% respectively of the totals for woody material, substantially more tha n the 47% of current wood production. Based on the size and distributi on of roots, the island may be composed of 30-40 individual layerings, most of which developed in the last 100 years.