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.

scholarly journals Land Cover and Land Use Change Decreases Net Ecosystem Production in Tropical Peatlands of West Kalimantan, Indonesia

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1587
Author(s):  
Imam Basuki ◽  
J. Boone Kauffman ◽  
James T. Peterson ◽  
Gusti Z. Anshari ◽  
Daniel Murdiyarso
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Soil Respiration ◽  
Primary Production ◽  
Oil Palm ◽  
Net Primary Production ◽  
Net Ecosystem Production ◽  
Carbon Sinks ◽  
Peat Swamp ◽  
Ecosystem Production

Deforested and converted tropical peat swamp forests are susceptible to fires and are a major source of greenhouse gas (GHG) emissions. However, information on the influence of land-use change (LUC) on the carbon dynamics in these disturbed peat forests is limited. This study aimed to quantify soil respiration (heterotrophic and autotrophic), net primary production (NPP), and net ecosystem production (NEP) in peat swamp forests, partially logged forests, early seral grasslands (deforested peat), and smallholder-oil palm estates (converted peat). Peat swamp forests (PSF) showed similar soil respiration with logged forests (LPSF) and oil palm (OP) estates (37.7 Mg CO2 ha−1 yr−1, 40.7 Mg CO2 ha−1 yr−1, and 38.7 Mg CO2 ha−1 yr−1, respectively), but higher than early seral (ES) grassland sites (30.7 Mg CO2 ha−1 yr−1). NPP of intact peat forests (13.2 Mg C ha−1 yr−1) was significantly greater than LPSF (11.1 Mg C ha−1 yr−1), ES (10.8 Mg C ha−1 yr−1), and OP (3.7 Mg C ha−1 yr−1). Peat swamp forests and seral grasslands were net carbon sinks (10.8 Mg CO2 ha−1 yr−1 and 9.1 CO2 ha−1 yr−1, respectively). In contrast, logged forests and oil palm estates were net carbon sources; they had negative mean Net Ecosystem Production (NEP) values (−0.1 Mg CO2 ha−1 yr−1 and −25.1 Mg CO2 ha−1 yr−1, respectively). The shift from carbon sinks to sources associated with land-use change was principally due to a decreased Net Primary Production (NPP) rather than increased soil respiration. Conservation of the remaining peat swamp forests and rehabilitation of deforested peatlands are crucial in GHG emission reduction programs.

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.

scholarly journals Impact of nitrogen fertilization on soil respiration and net ecosystem production in maize

2018 ◽  
Vol 64 (No. 8) ◽  
pp. 353-360 ◽  
Author(s):  
Lamptey Shirley ◽  
Li Lingling ◽  
Xie Junhong
Keyword(s):  
Soil Respiration ◽  
Primary Production ◽  
Soil Water ◽  
Nitrogen Fertilization ◽  
Field Experiments ◽  
Net Primary Production ◽  
Net Ecosystem Production ◽  
Water Dynamics ◽  
Ecosystem Production ◽  
Heavy Carbon

Agriculture in the semi-arid is often challenged by overuse of nitrogen (N), inadequate soil water and heavy carbon emissions thereby threatening sustainability. Field experiments were conducted to investigate the effect of nitrogen fertilization levels (N<sub>0</sub> – 0, N<sub>100</sub> – 100, N<sub>200</sub> – 200, N<sub>300</sub> – 300 kg N/ha) on soil water dynamics, soil respiration (Rs), net ecosystem production (NEP), and biomass yields. Zero nitrogen soils decreased Rs by 23% and 16% compared to N<sub>300</sub> and N<sub>200</sub> soils, respectively. However, biomass yield was greatest under N<sub>300</sub> compared with N<sub>0</sub>, which therefore translated into increased net primary production by 89% and NEP by 101% compared to N<sub>0</sub>. To a lesser extent, N<sub>200</sub> increased net primary production by 69% and net ecosystem production by 79% compared to N<sub>0</sub>. Grain yields were greatest under N<sub>300</sub> compared with N<sub>100</sub> and N<sub>0</sub>, which therefore translated into increased carbon emission efficiency (CEE) by 53, 39 and 3% under N<sub>300</sub> compared to N<sub>0</sub>, N<sub>100</sub> and N<sub>200</sub> treatments, respectively. There appears potential for 200 kg N/ha to be used to improve yield and increase CEE.

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.

scholarly journals North American boreal forests are a large carbon source due to wildfires from 1986 to 2016

2020 ◽  
Author(s):  
Bailu Zhao ◽  
Qianlai Zhuang ◽  
Narasinha Shurpali ◽  
Kajar Köster ◽  
Frank Berninger ◽  
...  
Keyword(s):  
Net Primary Production ◽  
Net Ecosystem Production ◽  
Ecosystem Dynamics ◽  
Fire Disturbance ◽  
Burn Severity ◽  
Fire Emissions ◽  
Terrestrial Ecosystem Model ◽  
C Balance ◽  
Ecosystem Production ◽  
The Impact

Abstract Wildfires are a major disturbance to forest carbon (C) balance through both immediate combustion emissions and post-fire ecosystem dynamics. Here we use a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to simulate C budget in Alaska and Canada during 1986-2016, as impacted by fire disturbances. We extracted the data of difference Normalized Burn Ratio (dNBR) for fires from Landsat TM/ETM imagery and estimated the proportion of vegetation and soil C combustion. We observed that the region is a C source of 2.74 Pg C during the 31-year period. The observed C loss, 57.1 Tg C yr-1, was attributed to fire emissions, overwhelming the net ecosystem production (1.9 Tg C yr-1) in the region. Our simulated during-fire emissions for Alaska and Canada are within the range of field measurements and other model estimates. As burn severity increases, combustion emission tended to switch from vegetation origin towards soil origin. Burn severity regulates post-fire C dynamics. Low severity fires increase soil temperature and decrease soil moisture and thus, enhance soil respiration. However, the opposite trend was found under moderate or high burn severity. The proportion of post-fire soil emission in total emissions increased with burn severity. Net nitrogen mineralization gradually recovered after fire, enhancing net primary production. Net ecosystem production recovered fast under higher burn severities. The impact of fire disturbance on the C balance of northern ecosystems and the associated uncertainties can be better characterized with long-term, prior, during- and post-disturbance data across the geospatial spectrum. Our findings suggest that the regional source of carbon to the atmosphere will persist if the observed forest wildfire occurrence and severity continues into the future.

Estimating net primary production of forests in the Canadian Prairie Provinces using an inventory-based carbon budget model

2002 ◽  
Vol 32 (1) ◽  
pp. 161-169 ◽  
Author(s):  
Zhong Li ◽  
Michael J Apps ◽  
E Banfield ◽  
Werner A Kurz
Keyword(s):  
Primary Production ◽  
Carbon Budget ◽  
Fine Root ◽  
Net Primary Production ◽  
Root Turnover ◽  
Stand Age ◽  
Parameter Estimates ◽  
Budget Model ◽  
Carbon Budget Model ◽  
Prairie Provinces

The Carbon Budget Model of the Canadian Forest Sector (CBM-CFS2) is a forest inventory-based ecosystem simulation model. It has been used previously for both retrospective and projective analyses of the carbon pools and fluxes of the Canadian forest ecosystems at the national, regional, and stand level. The objective of this study was to determine and evaluate forest net primary production (NPP) in the three Prairie Provinces in west-central Canada, as estimated by the model. The model simulated an averaged aboveground NPP (NPPA) of 172 g C·m–2·year–1 for the regional forests, varying from 72 to 293 g C·m–2·year–1, depending on ecoclimatic province, forest type, age, and site productivity. Comparisons of NPPA estimates for the boreal forest (165–179 g C·m–2·year–1) with results from direct measurements, modeling, and empirical calculations show that the CBM-CFS2 produced reasonable estimates of NPPA. The model incorporates different types of disturbances such as wildfire, harvesting, and insects and is able to evaluate NPP changes with stand age. However, belowground NPP may be overestimated, especially for young and unproductive stands. This can be explained by the current parameter estimates for the fine-root component of belowground biomass and for fine-root turnover rates.

scholarly journals North American Boreal Forests Are a Large Carbon Source Due to Wildfires From 1986 to 2016

2020 ◽  
Author(s):  
Bailu Zhao ◽  
Qianlai Zhuang ◽  
Narasinha Shurpali ◽  
Kajar Köster ◽  
Frank Berninger ◽  
...  
Keyword(s):  
Net Primary Production ◽  
Net Ecosystem Production ◽  
Ecosystem Dynamics ◽  
Fire Disturbance ◽  
Burn Severity ◽  
Fire Emissions ◽  
Terrestrial Ecosystem Model ◽  
C Balance ◽  
Ecosystem Production ◽  
The Impact

Abstract Wildfires are a major disturbance to forest carbon (C) balance through both immediate combustion emissions and post-fire ecosystem dynamics. Here we use a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to simulate C budget in Alaska and Canada during 1986-2016, as impacted by fire disturbances. We extracted the data of difference Normalized Burn Ratio (dNBR) for fires from Landsat TM/ETM imagery and estimated the proportion of vegetation and soil C combustion. We observed that the region is a C source of 2.74 Pg C during the 31-year period. The observed C loss, 57.1 Tg C yr-1, was attributed to fire emissions, overwhelming the net ecosystem production (1.9 Tg C yr-1) in the region. Our simulated during-fire emissions for Alaska and Canada are within the range of field measurements and other model estimates. As burn severity increases, combustion emission tended to switch from vegetation origin towards soil origin. When dNBR is below 300, fires increase soil temperature and decrease soil moisture and thus, enhance soil respiration. However, the opposite trend was found under moderate or high burn severity. The proportion of post-fire soil emission in total emissions increased with burn severity. Net nitrogen mineralization gradually recovered after fire, enhancing net primary production. Net ecosystem production recovered fast under higher burn severities. The impact of fire disturbance on the C balance of northern ecosystems and the associated uncertainties can be better characterized with long-term, prior, during- and post-disturbance data across the geospatial spectrum. Our findings suggest that the regional source of carbon to the atmosphere will persist if the observed forest wildfire occurrence and severity continues into the future.

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