Effect of nitrogen on the seasonal course of growth and maintenance respiration in stems of Norway spruce trees

Abstract

To determine effects of stem nitrogen concentration ([N]) on the seasonal course of respiration, rates of stem respiration of ten control and ten irrigated-fertilized (IL), 30-year-old Norway spruce trees (Picea abies (L.) Karst.), growing in northern Sweden, were measured on seven occasions from June 1993 to April 1994. To explore sources of seasonal variation and mechanisms of fertilization effects on respiration, we separated total respiration into growth and maintenance respiration for both xylem and phloem bark. Stem respiration increased in response to the IL treatment and was positively correlated with growth rate, volume of living cells and stem nitrogen content. However, no significant effect of IL treatment or [N] in the living cells was found for respiration per unit volume of live cells. Total stem respiration during the growing season (June to September) was estimated to be 16.7 and 29.7 mol CO(2) m(-2) for control and IL-treated trees, respectively. Respiration during the growing season accounted for approximately 64% of total annual respiration. Depending on the method, estimated growth respiration varied between 40 and 60% of total respiration during the growing season. Between 75 and 80% of the live cell volume in the stems was in the phloem, and phloem maintenance accounted for about 70% of maintenance respiration. Because most of the living cells were found in the phloem, and the living xylem cells were concentrated in the outer growth rings, we concluded that the best base for expressing rates of stem growth and maintenance respiration in young Norway spruce trees is stem surface area.

Spatial and seasonal variations in stem respiration of beech trees (Fagus sylvatica)

“…This is necessary for estimating the growth respiration coefficient by the periodic-growth method. In Stockfors and Linder [46], it was noted that the lag between growth and respiration peaks varied between 10 and 20 days for Picea abies. A possible explanation for this phenomenon is the lag between diameter growth and increase in dry matter caused by a delay in wall thickening and lignification [50].…”

“…[2,41]: growth respiration, which provides the energy needed to synthesise new tissues, is a function of wood growth; and maintenance respiration, which maintains existing living cells, is usually a function of biomass [36], sapwood volume [19], surface area [46] or nitrogen content [28]. This separation in two components is necessary to understand how stand development, climate and management affect forest carbon cycling.…”

“…(2) The distribution of living cells within the stem can affect maintenance respiration rates [45,46]. (3) The transport and storage of carbohydrates in the stem and in the branches can cause variations in respiration rates as it was shown by Malkina et al [29] and Lavigne [18].…”

“…More information is also needed to be able to choose the best unit to scale up stem or branch respiration to stand level, because this unit can have a large impact on the final results. Hitherto, the most common units have been surface area [18,46] or sapwood volume [36], but sapwood fresh mass [49] or sapwood dry mass and nitrogen content [28,[37][38][39][40] have also been used to express maintenance respiration. Sprugel et al [43] suggested that sapwood volume was a better calculation base, because respiration rates per unit volume are rather constant within coniferous species.…”

Effects of xylem water transport on CO2 efflux of woody tissue in a tropical tree, Amazonas State, Brazil

“…However, some studies found CO 2 effl ux rates lower than predicted from bark surface or sap wood temperature during daytime, which suggests an inner transport of CO 2 dissolved in the transpiration stream, as maybe ongoing bark photosynthesis could be excluded (Edwards & McLaughlin 1978, Kaipiainen et al 1998, Stockfors & Linder 1998. It is assumed that a portion of the CO 2 produced by the living respiring cells might dissolve in the sap and is transported vertically in the xylem along with the transpirational water uptake instead of moving laterally through the stem into the respiration chamber (Kaipiainen et al 1998) and hence this measured CO 2 efflux might not be equal to the respiration rate (Saveyn et al 2008).…”