Forest Carbon Sinks in the Northern Hemisphere

Abstract

There is general agreement that terrestrial systems in the Northern Hemisphere provide a significant sink for atmospheric CO2; however, estimates of the magnitude and distribution of this sink vary greatly. National forest inventories provide strong, measurement‐based constraints on the magnitude of net forest carbon uptake. We brought together forest sector C budgets for Canada, the United States, Europe, Russia, and China that were derived from forest inventory information, allometric relationships, and supplementary data sets and models. Together, these suggest that northern forests and woodlands provided a total sink for 0.6–0.7 Pg of C per year (1 Pg = 1015 g) during the early 1990s, consisting of 0.21 Pg C/yr in living biomass, 0.08 Pg C/yr in forest products, 0.15 Pg C/yr in dead wood, and 0.13 Pg C/yr in the forest floor and soil organic matter. Estimates of changes in soil C pools have improved but remain the least certain terms of the budgets. Over 80% of the estimated sink occurred in one‐third of the forest area, in temperate regions affected by fire suppression, agricultural abandonment, and plantation forestry. Growth in boreal regions was offset by fire and other disturbances that vary considerably from year to year. Comparison with atmospheric inversions suggests significant land C sinks may occur outside the forest sector.

Characterizing 3D vegetation structure from space: Mission requirements

“…The total amount of carbon contained in the forest's biomass is not known to even 232 one significant Figure. Estimates range from 385 to 650 PgC (Saugier et al 2001, FAO 233 2001, Goodale et al 2002 and tree volume) [MacArthur and MacArthur, 1961;Anderson and Shugart 1974;275 Willson 1974;Morgan and Freedman 1986]. As described in section 1.3 these same 276 variables are also needed to estimate biomass.…”

“…In addition to cycling carbon to and from the atmosphere, forests also play a 146 major role in climate change by affecting the exchange of solar energy and water between 147 the atmosphere and the Earth's surface; increasing forest cover reduces albedo, increasing 148 radiative climate forcing, but increases evapotranspiration and carbon uptake by forests, 149 decreasing climate forcing overall (Bounoua et al, 2000(Bounoua et al, , 2010. However, forest extent 150 and structure are both being rapidly altered by land use change ( Figure 2) The total amount of carbon contained in the forest's biomass is not known to even 232 one significant Figure. Estimates range from 385 to 650 PgC (Saugier et al 2001, FAO 233 2001, Goodale et al 2002 Structure and biomass can vary as much within ecosystems as between them. The 264 variability results in part from differences in disturbance modalities, physiognomy and 265 recovery processes at the much fine scales of forest disturbance and regrowth.…”

Parallel Seasonal Patterns of Photosynthesis, Fluorescence, and Reflectance Indices in Boreal Trees

“…The boreal region, known to be a substantial store of carbon [3], is experiencing a significant change in climate. The combined effects of increasing atmospheric carbon dioxide (CO 2 ) levels and increasing temperatures associated with climate change will impact a number of plant processes [4], and these effects are amplified at higher latitudes.…”

Biomass conversion factors (density and carbon concentration) by decay classes for dead wood of Pinus sylvestris, Picea abies and Betula spp. in boreal forests of Sweden

“…the forests sequester more than they emit (Harmon and Hua, 1991;Kauppi et al, 1992;Dixon et al, 1994). Goodale et al (2002) report that these forests together provided a net sink of 0.6-0.7 Pg of C per year during the early 1990s, of which 0.15 Pg C per year in dead wood. Earlier estimations of the C sequestration have lately shown to be too low).…”

“…Earlier estimations of the C sequestration have lately shown to be too low). (Goodale et al, 2002). A large part of this underestimation is probably due to the lack of existing reporting methods of coarse woody debris.…”