Seasonal and spatial variation of woody tissue respiration in a Pinus cembra tree at the alpine timberline in the central Austrian Alps

Berlin

2004

Artikel aus einer ZeitschriftUnselbständiges Werk

I-11934; 9556S

200111414

Total stem, branch, twig, and coarse root respiration (Rt) of an adult Pinus cembra tree at the alpine timberline was measured continuously at ten positions from 7 October 2001 to 21 January 2003 with an automated multiplexing gas exchange system. There was a significant spatial variability in woody tissue respiration when expressed per unit surface area or per unit sapwood volume. Surface area related maintenance (Rm) respiration at 0°C ranged between 0.109 and 0.643 mol m–2 s–1 and there was no clear trend with respect to tissue type and diameter. Sapwood volume based Rm at 0°C by contrast, varied between 2.5 mol m–3 s–1 in the stem and 193.2 mol m–3 s–1 in thin twigs in the upper crown. Estimated Q10 values ranged from 1.7 to 3.1. These Q10 values were used along with Rm at 0°C and annual woody tissue temperature records to predict annual total Rm. Annual total Rm accounted for 73ء6% of annual Rt in 2002.