Net Primary Production and Carbon Allocation Patterns of Boreal Forest Ecosystems

Abstract

The three objectives of this paper were: to summarize net primary production (NPP) and carbon allocation patterns for boreal forests, to examine relationships between climatic and biological variables and NPP, and to examine carbon allocation coefficients for all boreal forests or types of boreal forests that can be used to estimate NPP from easily measured components of NPP. Twenty‐four Class I stands (complete NPP budgets) and 45 Class II boreal forest stands (aboveground NPP [NPPA] and budget only) were identified. The geographic distribution of the Class I stands was not uniform; 46% of the stands were from two studies in North America, and only one stand was from the important larch forests of Eurasia. Total (above‐ and belowground) net primary production (NPPT) ranged from 52 to 868 g C·m−2·yr−1 and averaged 424 g C·m−2·yr−1. NPPA was consistently larger for deciduous than for evergreen boreal forests in each of the major boreal regions, especially for boreal forests in Alaska. Belowground net primary production:total net primary production (NPPB : NPPT) ratios were consistently larger for evergreen (0.36) than deciduous (0.19) boreal forests. NPP of different‐aged stands in age sequence varied from 44% to 77%, a magnitude equal to or greater than that of climatic factors or vegetation type. NPP and NPPA were positively correlated (r2 = 0.66–0.68) to mean annual aboveground increment for Class I stands, and this empirical relationship explained 81% of the observed variation of NPPA for Class II stands. These robust relationships provide an approach for increasing the number and spatial coverage of boreal forest NPP data needed to evaluate NPP estimates from ecosystem models. Notable deficiencies of boreal forest NPP data were ground layer vegetation and belowground NPP data, NPP data for boreal forest age sequences, and NPP data for boreal larch ecosystems in Eurasia.

Cross‐regional prediction of long‐term trajectory of stream water DOC response to climate change

“…While this disproportionately large soil carbon stock provides one of the most sensitive positive feedback scenarios for climatic warming [Gower et al, 2001], it is also a large potential pool for increasing C export via aquatic pathways [Frey and McClelland, 2009]. However, contrary to most previous reports, our simple regional MAT-DOC concentration model suggests that new long-term steady-state conditions will not necessary always result in higher DOC concentrations in aquatic environments.…”

Relationships between Wood Formation and Cambium Phenology on the Tibetan Plateau during 1960–2014

“…The effect of a longer growing season on the formation of wood can be biased by a decreased formation rate or reduced cell size [15,47,48]. The different allocation strategies of absorbed carbon by a tree probably result in more complex relationships between wood formation and cambium phenology [7,49]. The variability of tree-ring width is also affected by the climate conditions during previous year(s) [50][51][52].…”

Environmental controls on ground cover species composition and productivity in a boreal black spruce forest

“…Boreal forests comprise 8% of the total area of terrestrial biomes, 13% of the total net primary production (NPP) of terrestrial biomes, and 31% of the total forest soil C (Gower et al 2001). Black spruce forests [Picea mariana (Mill.) BSP] are a major boreal ecosystem in North America (Van Cleve et al 1983;Aber and Melillo 1991).…”

“…The live biomass of bryophytes comprises a small fraction of the total ecosystem C content, but greatly influences the function of the ecosystem (Oechel and Van Cleve 1986). Bryophytes affect soil thermal regimes, hydrology and nutrient availability (Van Cleve and Viereck 1981;Van Cleve et al 1983;Van Cleve and Yarie 1986;Sveinbjornsson and Oechel 1992), and the NPP of bryophytes can equal or exceed overstory NPP (Oechel and Van Cleve 1986;Gower et al 1997Gower et al , 2001.…”

“…Estimates of boreal forest NPP, especially for the ground layer comprising bryophytes, are limited (Gower et al 2001). A better understanding of the factors influencing bryophyte distribution and NPP is needed to quantify the boreal forest C cycle because of the large contribution of bryophyte NPP and their influence on the microenvironment of boreal black spruce forests.…”