scholarly journals Could increased boreal forest ecosystem productivity offset carbon losses from increased disturbances?

2007 ◽  
Vol 363 (1501) ◽  
pp. 2259-2268 ◽  
Author(s):  
Werner A Kurz ◽  
Graham Stinson ◽  
Greg Rampley
Keyword(s):  
Boreal Forest ◽  
Net Primary Production ◽  
Natural Disturbance ◽  
Climatic Changes ◽  
Forest Sector ◽  
Carbon Budget Model ◽  
C Stocks ◽  
Carbon Losses ◽  
Forest C ◽  
Landscape Level

To understand how boreal forest carbon (C) dynamics might respond to anticipated climatic changes, we must consider two important processes. First, projected climatic changes are expected to increase the frequency of fire and other natural disturbances that would change the forest age-class structure and reduce forest C stocks at the landscape level. Second, global change may result in increased net primary production (NPP). Could higher NPP offset anticipated C losses resulting from increased disturbances? We used the Carbon Budget Model of the Canadian Forest Sector to simulate rate changes in disturbance, growth and decomposition on a hypothetical boreal forest landscape and to explore the impacts of these changes on landscape-level forest C budgets. We found that significant increases in net ecosystem production (NEP) would be required to balance C losses from increased natural disturbance rates. Moreover, increases in NEP would have to be sustained over several decades and be widespread across the landscape. Increased NEP can only be realized when NPP is enhanced relative to heterotrophic respiration. This study indicates that boreal forest C stocks may decline as a result of climate change because it would be difficult for enhanced growth to offset C losses resulting from anticipated increases in disturbances.

Temporal changes of forest net primary production and net ecosystem production in west central Canada associated with natural and anthropogenic disturbances

2003 ◽  
Vol 33 (12) ◽  
pp. 2340-2351 ◽  
Author(s):  
Zhong Li ◽  
Michael J Apps ◽  
Werner A Kurz ◽  
Ed Banfield
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
Anthropogenic Disturbances ◽  
Temporal Variations ◽  
Net Ecosystem Production ◽  
Forest Sector ◽  
Natural Disturbances ◽  
Carbon Budget Model ◽  
West Central ◽  
Ecosystem Production

Temporal variations of net primary production (NPP) and net ecosystem production (NEP) in west central Canadian forests over the period of 1920–1995 and their responses to natural and anthropogenic disturbances were simulated using the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS2). The results show that forest NPP in the region was 215 g C·year–1·m–2 in 1920, varied between 105 and 317 g·C year–1·m–2 depending on ecoclimatic province, but gradually increased to 330 (158 to 395) g C·year–1·m–2 in the early 1980s before declining to 290 (148 to 395) g C·year–1·m–2 by 1995. Forest NEP was estimated to be 53 (–13 to 88) g C·year–1·m–2 in 1920–1924, increased to 75 (5 to 98) g C·year–1·m–2 in 1960, and then declined to 26 (–14 to 53) g C·year–1·m–2 in 1991–1995. Natural disturbances played a greater role than harvest in determining the temporal pattern of forest NPP and NEP during the period because of the larger area affected by natural disturbances. This study also indicated that ignoring disturbances would lead to an overestimation of forest NPP and NEP in ecosystem modeling.

Belowground biomass dynamics in the Carbon Budget Model of the Canadian Forest Sector: recent improvements and implications for the estimation of NPP and NEP

2003 ◽  
Vol 33 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Zhong Li ◽  
Werner A Kurz ◽  
Michael J Apps ◽  
Sarah J Beukema
Keyword(s):  
Primary Production ◽  
Root Biomass ◽  
Carbon Budget ◽  
Fine Root ◽  
Net Primary Production ◽  
Fine Root Biomass ◽  
Forest Sector ◽  
Regression Equations ◽  
Budget Model ◽  
Carbon Budget Model

In the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS2), root biomass and dynamics are estimated using regression equations based on the literature. A recent analysis showed that some of these equations might overestimate belowground net primary production (NPPB). The objectives of this study were to update the compilation of root biomass and turnover data, to recalculate the regression equations and to evaluate the impact of the new equations on CBM-CFS2 estimates of net primary production (NPP) and net ecosystem production (NEP). We updated all equations based on 635 pairs of aboveground and belowground data compiled from published studies in the cold temperate and boreal forests. The new parameter for the equation to predict total root biomass for softwood species changed only slightly, but the changes for hardwood species were statistically significant. A new equation form, which improved the accuracy and biological interpretation, was used to predict fine root biomass as a proportion of total root biomass. The annual rate of fine root turnover was currently estimated to be 0.641 of fine root biomass. A comparison of NPP estimates from CBM-CFS2 with results from field measurements, empirical calculations and modeling indicated that the new root equations predicted reasonable NPPB values. The changes to the root equations had little effect on NEP estimates.

Carbon in Canada’s boreal forest — A synthesis

2013 ◽  
Vol 21 (4) ◽  
pp. 260-292 ◽  
Author(s):  
W.A. Kurz ◽  
C.H. Shaw ◽  
C. Boisvenue ◽  
G. Stinson ◽  
J. Metsaranta ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Large Scale ◽  
Net Primary Production ◽  
Wood Products ◽  
Heterotrophic Respiration ◽  
Organic Soils ◽  
Cold Temperatures ◽  
C Pools ◽  
C Balance ◽  
C Stocks

Canada’s managed boreal forest, 54% of the nation’s total boreal forest area, stores 28 Pg carbon (C) in biomass, dead organic matter, and soil pools. The net C balance is dominated by the difference of two large continuous fluxes: C uptake (net primary production) and release during decomposition (heterotrophic respiration). Additional releases of C can be high in years, or in areas, that experience large anthropogenic or natural disturbances. From 1990 to 2008, Canada’s managed boreal forest has acted as C sink of 28 Tg C year−1, removing CO2from the atmosphere to replace the 17 Tg of C annually harvested and store an additional 11 Tg of C year−1in ecosystem C pools. A large fraction (57%) of the C harvested since 1990 remains stored in wood products and solid waste disposal sites in Canada and abroad, replacing C emitted from the decay or burning of wood harvested prior to 1990 and contributing to net increases in product and landfill C pools. Wood product use has reduced emissions in other sectors by substituting for emission-intensive products (concrete, steel). The C balance of the unmanaged boreal forest is currently unknown. The future C balance of the Canadian boreal forest will affect the global atmospheric C budget and influence the mitigation efforts required to attain atmospheric CO2stabilization targets. The single biggest threat to C stocks is human-caused climate change. Large C stocks have accumulated in the boreal because decomposition is limited by cold temperatures and often anoxic environments. Increases in temperatures and disturbance rates could result in a large net C source during the remainder of this century and beyond. Uncertainties about the impacts of global change remain high, but we emphasize the asymmetry of risk: sustained large-scale increases in productivity are unlikely to be of sufficient magnitude to offset higher emissions from increased disturbances and heterotrophic respiration. Reducing the uncertainties of the current and future C balance of Canada’s 270 Mha of boreal forest requires addressing gaps in monitoring, observation, and quantification of forest C dynamics, with particular attention to 125 Mha of unmanaged boreal forest with extensive areas of deep organic soils, peatlands, and permafrost containing large quantities of C that are vulnerable to global warming.

Forest carbon stocks in Newfoundland boreal forests of harvest and natural disturbance origin I: field study

2010 ◽  
Vol 40 (11) ◽  
pp. 2135-2145 ◽  
Author(s):  
M. T. Moroni ◽  
C. H. Shaw ◽  
P. Otahal
Keyword(s):  
Mineral Soil ◽  
Abies Balsamea ◽  
Natural Disturbance ◽  
Mitigation Strategies ◽  
Disturbance History ◽  
Dead Tree ◽  
Soil C ◽  
C Stocks ◽  
Live Tree ◽  
Forest C

Quantification of stand and forest C stocks in response to different disturbances is necessary to develop climate change mitigation strategies and to evaluate forest C accounting tools. Live tree, dead tree, woody debris (WD), stump, buried wood, and organic and mineral soil C stocks are described in chronosequences of black spruce ( Picea mariana (Mill.) BSP) (harvest and fire origin) and balsam fir ( Abies balsamea (L.) Mill.) (insect and harvest origin). The largest C stocks were found in mineral soil (≤179 Mg·ha–1), organic soil (≤123 Mg·ha–1), and live tree (≤93 Mg·ha–1) pools. Live tree C changed predictably with disturbance history and time since disturbance, increasing with forest age. Regeneration growth slowed under snags. Thinning accelerated production of larger trees but reduced site live tree C. Dead tree and WD C were temporally dynamic and strongly influenced by disturbance history and time since disturbance, but abundances in differently disturbed forests converged at low levels 40–60 years after disturbance. Only immediately following natural disturbances were there large amounts of snag C (26–30 Mg·ha–1). WD C was relatively abundant <3 years after harvesting (15–17 Mg·ha–1) and 31–36 years after natural disturbance (9 Mg·ha–1). Buried wood stocks were small, but comparable with WD stocks in some forests.

Ecosystem modeling of methane and carbon dioxide fluxes for boreal forest sites

2001 ◽  
Vol 31 (2) ◽  
pp. 208-223 ◽  
Author(s):  
Christopher Potter ◽  
Jill Bubier ◽  
Patrick Crill ◽  
Peter Lafleur
Keyword(s):  
Carbon Dioxide ◽  
Boreal Forest ◽  
Land Surface ◽  
Net Primary Production ◽  
Ground Cover ◽  
Methane Flux ◽  
Growing Season ◽  
Ecosystem Model ◽  
Heat Fluxes ◽  
Water Levels

Predicted daily fluxes from an ecosystem model for water, carbon dioxide, and methane were compared with 1994 and 1996 Boreal Ecosystem–Atmosphere Study (BOREAS) field measurements at sites dominated by old black spruce (Picea mariana (Mill.) BSP) (OBS) and boreal fen vegetation near Thompson, Man. Model settings for simulating daily changes in water table depth (WTD) for both sites were designed to match observed water levels, including predictions for two microtopographic positions (hollow and hummock) within the fen study area. Water run-on to the soil profile from neighboring microtopographic units was calibrated on the basis of daily snowmelt and rainfall inputs to reproduce BOREAS site measurements for timing and magnitude of maximum daily WTD for the growing season. Model predictions for daily evapotranspiration rates closely track measured fluxes for stand water loss in patterns consistent with strong controls over latent heat fluxes by soil temperature during nongrowing season months and by variability in relative humidity and air temperature during the growing season. Predicted annual net primary production (NPP) for the OBS site was 158 g C·m–2 during 1994 and 135 g C·m–2 during 1996, with contributions of 75% from overstory canopy production and 25% from ground cover production. Annual NPP for the wetter fen site was 250 g C·m–2 during 1994 and 270 g C·m–2 during 1996. Predicted seasonal patterns for soil CO2 fluxes and net ecosystem production of carbon both match daily average estimates at the two sites. Model results for methane flux, which also closely match average measured flux levels of –0.5 mg CH4·m–2·day–1 for OBS and 2.8 mg CH4·m–2·day–1 for fen sites, suggest that spruce areas are net annual sinks of about –0.12 g CH4·m–2, whereas fen areas generate net annual emissions on the order of 0.3–0.85 g CH4·m–2, depending mainly on seasonal WTD and microtopographic position. Fen hollow areas are predicted to emit almost three times more methane during a given year than fen hummock areas. The validated model is structured for extrapolation to regional simulations of interannual trace gas fluxes over the entire North America boreal forest, with integration of satellite data to characterize properties of the land surface.

scholarly journals Utikuma Region Study Area (URSA) – Part 1: Hydrogeological and ecohydrological studies (HEAD)

2016 ◽  
Vol 92 (01) ◽  
pp. 57-61 ◽  
Author(s):  
Kevin J. Devito ◽  
Carl Mendoza ◽  
Richard M. Petrone ◽  
Nick Kettridge ◽  
James M. Waddington
Keyword(s):  
Boreal Forest ◽  
Conceptual Understanding ◽  
Natural Disturbance ◽  
Spatially Explicit ◽  
Forest Research ◽  
Boreal Plains ◽  
Process Studies ◽  
Hydrogeological Studies ◽  
Western Boreal Forest

The Utikuma Region Study Area (URSA) was initiated to develop spatially explicit modelling tools to predict the cumulative impacts of land use and natural disturbance on the Boreal Plains (BP) ecozone of the Western Boreal Forest. Research comprised several multi-year projects, spanning wet and dry climate periods that combined intensive detailed process studies at seven watersheds with extensive long-term ecohydrological and hydrogeological studies conducted across a 60-km transect representing the range of glaciated landforms characteristic of the sub-humid boreal forest in Alberta. These studies have improved our conceptual understanding and capacity to numerically model how climate and geology influence water and energy flow, and the hydrologic linkages and natural variability of the key processes influencing BP ecosystems. Eco-hydrogeological frameworks have been developed for designing, conducting, interpreting, and extrapolating research results for watershed management and construction across the Boreal Plain ecozone.

scholarly journals Reforestation can sequester two petagrams of carbon in US topsoils in a century

2018 ◽  
Vol 115 (11) ◽  
pp. 2776-2781 ◽  
Author(s):  
Lucas E. Nave ◽  
Grant M. Domke ◽  
Kathryn L. Hofmeister ◽  
Umakant Mishra ◽  
Charles H. Perry ◽  
...  
Keyword(s):  
National Level ◽  
Mineral Soil ◽  
C Sequestration ◽  
The United States ◽  
Forest Sector ◽  
Soil C ◽  
C Storage ◽  
C Stocks ◽  
The Us ◽  
Land Use And Management

Soils are Earth’s largest terrestrial carbon (C) pool, and their responsiveness to land use and management make them appealing targets for strategies to enhance C sequestration. Numerous studies have identified practices that increase soil C, but their inferences are often based on limited data extrapolated over large areas. Here, we combine 15,000 observations from two national-level databases with remote sensing information to address the impacts of reforestation on the sequestration of C in topsoils (uppermost mineral soil horizons). We quantify C stocks in cultivated, reforesting, and natural forest topsoils; rates of C accumulation in reforesting topsoils; and their contribution to the US forest C sink. Our results indicate that reforestation increases topsoil C storage, and that reforesting lands, currently occupying >500,000 km2 in the United States, will sequester a cumulative 1.3–2.1 Pg C within a century (13–21 Tg C·y−1). Annually, these C gains constitute 10% of the US forest sector C sink and offset 1% of all US greenhouse gas emissions.

Agriculture in the Boreal Forest: Understanding the Impact of Land Use Change on Soil Carbon for Developing Sustainable Community Food Systems 

2021 ◽  
Author(s):  
David Bysouth ◽  
Merritt Turetsky ◽  
Andrew Spring
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Boreal Forest ◽  
Soil Carbon ◽  
Food Systems ◽  
Agricultural Land ◽  
Carbon Stocks ◽  
Soil Carbon Stocks ◽  
Carbon Losses

&lt;p&gt;Climate change is causing rapid warming at northern high latitudes and disproportionately affecting ecosystem services that northern communities rely upon. In Canada&amp;#8217;s Northwest Territories (NWT), climate change is impacting the access and availability of traditional foods that are critical for community health and well-being. With climate change potentially expanding the envelope of suitable agricultural land northward, many communities in the NWT are evaluating including agriculture in their food systems. However, the conversion of boreal forest to agriculture may degrade the carbon rich soils that characterize the region, resulting in large carbon losses to the atmosphere and the depletion of existing ecosystem services associated with the accumulation of soil organic matter. Here, we first summarize the results of 35 publications that address land use change from boreal forest to agriculture, with the goal of understanding the magnitude and drivers of carbon stock changes with time-since-land use change. Results from the literature synthesis show that conversion of boreal forest to agriculture can result in up to ~57% of existing soil carbon stocks being lost 30 years after land use change occurs. In addition, a three-way interaction with soil carbon, pH and time-since-land use change is observed where soils become more basic with increasing time-since-land use change, coinciding with declines in soil carbon stocks. This relationship is important when looking at the types of crops communities are interested in growing and the type of agriculture associated with cultivating these crops. Partnered communities have identified crops such as berry bushes, root vegetables, potatoes and corn as crops they are interested in growing. As berry bushes grow in acidic conditions and the other mentioned crops grow in more neutral conditions, site selection and management practices associated with growing these crops in appropriate pH environments will be important for managing soil carbon in new agricultural systems in the NWT. Secondly, we also present community scale soil data assessing variation in soil carbon stocks in relation to potential soil fertility metrics targeted to community identified crops of interest for two communities in the NWT.&amp;#160; We collected 192 soil cores from two communities to determine carbon stocks along gradients of potential agriculture suitability. Our field soil carbon measurements in collaboration with the partnered NWT communities show that land use conversions associated with agricultural development could translate to carbon losses ranging from 2.7-11.4 kg C/m&lt;sup&gt;2&lt;/sup&gt; depending on the type of soil, agricultural suitability class, and type of land use change associated with cultivation. These results highlight the importance of managing soil carbon in northern agricultural systems and can be used to emphasize the need for new community scale data relating to agricultural land use change in boreal soils. Through the collection of this data, we hope to provide northern communities with a more robust, community scale product that will allow them to make informed land use decisions relating to the cultivation of crops and the minimization of soil carbon losses while maintaining the culturally important traditional food system.&lt;/p&gt;

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