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.

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.

Estimation of root biomass and dynamics for the carbon budget model of the Canadian forest sector

1996 ◽  
Vol 26 (11) ◽  
pp. 1973-1979 ◽  
Author(s):  
Werner A. Kurz ◽  
Sarah J. Beukema ◽  
Michael J. Apps
Keyword(s):  
Aboveground Biomass ◽  
Root Biomass ◽  
Regression Models ◽  
Carbon Budget ◽  
Fine Root ◽  
Root Production ◽  
Forest Sector ◽  
Budget Model ◽  
Carbon Budget Model ◽  
Hardwood Species

Root biomass is expected to contribute significantly to total ecosystem carbon (C) pools and their dynamics. A method for estimating belowground biomass pools and their dynamics was developed for application in the carbon budget model of the Canadian forest sector (CBM-CFS2). Root biomass data for temperate and boreal softwood and hardwood species were compiled from the literature. Total root biomass for softwood and hardwood species was estimated using regression models that incorporate total aboveground biomass as the independent variable. Fine root biomass was estimated as a proportion of total root biomass using a single regression model for softwood and hardwood species combined. A regression model to estimate annual fine root production was derived for softwood and hardwood species. In the CBM-CFS2, net increments of total biomass were estimated using empirical growth functions to predict aboveground biomass. The regression models developed in this study were then used to predict the corresponding root biomass. Total root production was calculated as the sum of net increments, i.e., the change in root biomass per hectare plus annual turnover. The application of this approach to estimate root biomass pools and their dynamics in the CBM-CFS2 is demonstrated. As with all regression models that are developed from regional databases, this approach should not be used to predict root biomass and dynamics of an individual forest ecosystem, because the influence of species, site, and stand characteristics may lead to significant deviations from the regional averages.

scholarly journals Using the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) to examine the impact of harvest and fire on carbon dynamics in selected forest types of the Canadian Boreal shield

2012 ◽  
Vol 88 (04) ◽  
pp. 426-438 ◽  
Author(s):  
N. Luckai ◽  
G.R. Larocque ◽  
L. Archambault ◽  
D. Paré ◽  
R. Boutin ◽  
...  
Keyword(s):  
Carbon Budget ◽  
Jack Pine ◽  
Forest Sector ◽  
Forest Types ◽  
Deep Soil ◽  
Budget Model ◽  
Carbon Budget Model ◽  
Fire Disturbances ◽  
Shallow Soils ◽  
The Impact

The objective of the study was to assess the responsiveness of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) to management scenarios that included three rotation lengths (50, 100 and 250 years) under harvest and fire disturbances in six forest types (poplar deep soil, black spruce deep soil, jack pine deep and shallow soils, hardwood mixedwood and other conifer lowland). Outputs from five carbon (C) pools were considered: merchantable stemwood (stump height of 30 cm, minimum DBH of 9 cm and a minimum top diameter of 7 cm), deadwood, soil C, total ecosystem C and cumulative total ecosystem C emissions. Yield curves strongly affected the predicted size of all five pools. Longer rotation lengths led to larger pools with the relative differences between rotation lengths varying with stand types. Pools associated with poplar were usually the largest while those of jack pine on shallow sites were generally the smallest. When compared to the starting point of the simulations, cumulative total ecosystem C and C emissions increased with the 100- and 250-year harvest rotations (HARV100 and HARV250, respectively) and declined with the 50-year harvest rotation (HARV50). Fire disturbances resulted in stable pools of cumulative ecosystem C and declines in C emissions. CBM-CFS3 provided realistic pool values but the authors suggest further development of the model depiction of ecosystem processes, especially with respect to the treatment of respiration. In general, the authors recommend that forest management planners consider using an integrated approach that links multiple proven and accepted models under appropriate model linking software.

A practical approach for assessing the sensitivity of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3)

2008 ◽  
Vol 219 (3-4) ◽  
pp. 373-382 ◽  
Author(s):  
Thomas White ◽  
Nancy Luckai ◽  
Guy R. Larocque ◽  
Werner A. Kurz ◽  
Carolyn Smyth
Keyword(s):  
Carbon Budget ◽  
Practical Approach ◽  
Forest Sector ◽  
Budget Model ◽  
Carbon Budget Model

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.

Effects of thinning on fine root biomass and carbon storage of subalpine Picea asperata plantation in Western Sichuan Province, China

2013 ◽  
Vol 36 (7) ◽  
pp. 645-654 ◽  
Author(s):  
Yun-Ke LIU ◽  
Chuan FAN ◽  
Xian-Wei LI ◽  
Yin-Hua LING ◽  
Yi-Gui ZHOU ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Sichuan Province ◽  
Western Sichuan ◽  
Picea Asperata
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