scholarly journals Biomass and production of an aspen – mixed hardwood – spodosol ecosystem in northern Wisconsin

1981 ◽  
Vol 11 (1) ◽  
pp. 132-138 ◽  
Author(s):  
John Pastor ◽  
J. G. Bockheim

Total biomass of an aspen – mixed hardwood – spodosol ecosystem in northern Wisconsin, U.S.A., was 197 t/ha and net primary production was 11.5 t/ha per year. Populustremuloides Michx. accounted for 60% of the total biomass and 56% of the annual production and Acersaccharum Marsh, accounted for 25% of the biomass and 28% of the annual production. For all species combined, bole wood was 63% of the total biomass and bole bark was 12%. Bole wood was 33% and bole bark was 7% of the total production. Although crowns accounted for only 15% of the total biomass, they were responsible for 49% of net annual production. Using allometric equations from the literature, root biomass and production were calculated as being approximately 10% of the total biomass and of the annual production. The average rate of total production per unit leaf tissue was 5.7 g production/g leaf tissue for P. tremuloides and 3.7 g/g for A. saccharum.

2019 ◽  
Vol 6 (2) ◽  
pp. 180890 ◽  
Author(s):  
Zhanyi Wang ◽  
Jing Jin ◽  
Yanan Zhang ◽  
Xiaojuan Liu ◽  
Yongling Jin ◽  
...  

The impacts of large herbivores on plant communities differ depending on the plants and the herbivores. Few studies have explored how herbivores influence root biomass. Root growth of vegetation was studied in the field with four treatments: sheep grazing alone (SG), cattle grazing alone (CG), mixed grazing with cattle and sheep (MG) and no grazing (CK). Live and total root biomasses were measured using the root ingrowth core and the drilling core, respectively. After 2 years of grazing, total root biomass showed a decreasing trend while live root biomass increased with time during the growing seasons. Belowground net primary production (BNPP) among the treatments varied from 166 ± 32 to 501 ± 88 g m −2 and root turnover rates (RTR) varied from 0.25 ± 0.05 to 0.70 ± 0.11 year −1 . SG had the greatest BNPP and RTR, while the CG had the smallest BNPP and RTR. BNPP and RTR of the MG treatment were between those of the CG and SG treatments. BNPP and RTR of the CK were similar to MG treatment. Compared with other treatments, CG had a greater impact on dominant tall grasses species in communities. SG could decrease community diversity. MG eliminated the disadvantages of single-species grazing and was beneficial to community diversity and stability.


2003 ◽  
Vol 33 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Zhong Li ◽  
Werner A Kurz ◽  
Michael J Apps ◽  
Sarah J Beukema

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.


1980 ◽  
Vol 10 (1) ◽  
pp. 92-101 ◽  
Author(s):  
Greg J. Koerper ◽  
Curtis J. Richardson

Dimension analysis techniques were used in the harvest of 31 largetooth aspen (Populusgrandidentata Michx.) from three mature stands (55 ± 7 years) representing a wide range of soil quality and clonal variation among aspen in northern lower Michigan, U.S.A. Regression equations were derived to predict component biomass and net annual production from tree dbh. Evaluation by analysis of covariance indicated significant differences (P < 0.05) in regression models among the sites.Total aboveground biomass of P. grandidentata was 171 565, 128 765, and 38 530 kg/ha at the good, intermediate, and poor soil sites where largetooth aspen constituted 81.5, 79.0, and 48.3% of the stand basal area, respectively. Corresponding aboveground net annual production values were 11 038, 7259, and 2925 kg/ha. Component percentages of total biomass were generally similar among sites, except for leaves. Variations in production percentages showed a production per unit leaf weight gradient parallel to the site quality gradient (i.e., poor site production per unit leaf weight was 33% less than the good site value). The errors inherent in the substitution of regressions derived from data from other sites were examined. Total biomass estimates ranged from −27 to +40% of accepted values. Errors for individual components ranged from −33 to +51%. Total aboveground biomass estimates from regressions for the combined data from all sites were acceptable within a standard error of the mean on the good and intermediate sites and with an allowance of 19% error on the poor site.


1971 ◽  
Vol 28 (10) ◽  
pp. 1573-1581 ◽  
Author(s):  
K. Radway Allen

A series of mathematical models of cohorts in animal populations representing various combinations of several different simple growth and mortality functions is examined to investigate the ratio between mean biomass and production over unit time, and to compare this ratio with the mean age and mean life span of the animals in the cohort.For any cohort, the ratio of production per unit time to mean biomass is equal to the ratio of total production by the cohort to its total biomass integral by time. For populations consisting of a number of simultaneous, successive, or overlapping cohorts, the ratio of production per unit time to mean biomass is equal to the mean of the ratios for the individual cohorts weighted by the mean biomasses of the cohorts.If the cohorts are identical, the population ratio is the same as the cohort ratio and problems arising from the presence of more than one cohort may be ignored. Formulations for the total production per cohort, biomass integral, and, where they can be simplified, their ratios, are given.Comparison with mean age and mean life span shows that for constant exponential mortality, mean age and mean life span are both equal to the reciprocal of the production–biomass ratio. For other mortality functions, if growth in weight is linear, the production–biomass ratio equals the reciprocal of the mean age. For other models there is no simple relation. In general, mean age appears a better approximation than mean life span to the reciprocal of the production–biomass ratio.These methods are applied, as an example, to Antarctic krill, using a model having linear growth in length and four periods with different exponential mortality rates. For this model, annual production is 1.8 times the mean biomass so that assumption of equality leads to an underestimate of production. Mean age and mean life span are 0.21 and 0.037 years respectively. Thus, use of either of these as an approximation, and particularly mean life span, leads to severe overestimation of annual production.


1975 ◽  
Vol 5 (3) ◽  
pp. 403-409 ◽  
Author(s):  
George R. Parker ◽  
G. Schneider

Total aboveground dry weight biomass and annual production were determined for two sites of different soil texture in an alder swamp of Michigan's upper peninsula. The more poorly drained site A averaged 5300 g/m2 and 640 g/m2 per year while site B averaged 3100 g/m2 and 570 g/m2 per year. The smaller standing-crop biomass on the better-drained site B is due to greater abundance of Alnusrugosa. The tree stratum constitutes 97 and 93% of the total biomass and 84 and 80% of the total production on site A and B, respectively. The understory strata constituted the remaining 3 and 16% of the biomass and production on site A and 7 and 20% on site B.


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