Regional variability in nitrogen mineralization, nitrification, and overstory biomass in northern Lower Michigan

1989 ◽  
Vol 19 (12) ◽  
pp. 1521-1526 ◽  
Author(s):  
Donald R. Zak ◽  
George E. Host ◽  
Kurt S. Pregitzer

Potential net nitrogen (N) mineralization, potential net nitrification, and overstory (boles and branches) biomass were measured in nine forest ecosystems commonly found within the well-drained uplands of northern Lower Michigan. The ecosystem types ranged from oak-dominated forests on coarse-textured outwash sands to mesic northern hardwood forests on sandy glacial till. Overstory biomass was calculated using species-specific allometric equations developed for Lake States hardwood species. Potential net N mineralization and potential net nitrification were measured by a 30-day aerobic laboratory soil incubation. Analyses of (co)variance were used to determine differences in potential N mineralization, net nitrification, overstory biomass, and biomass increment among the nine ecosystem types. Linear and nonlinear regression analyses were used to predict overstory biomass and biomass increment using potential net N mineralization as the independent variable. Overstory biomass ranged from 92 t•ha−1 in a xeric oak ecosystem to 243 t•ha−1 in a northern hardwood ecosystem; annual biomass production ranged from 1.3 to 3.5 t•ha−1 year−1, respectively. Potential net N mineralization was lowest in the xeric oak ecosystem (52.0 μg N•g−1) and greatest in the mesic northern hardwood ecosystem (127.8 μg N•g−1). Potential net nitrification was 45.5 μg NO3−-N•g−1 in the northern hardwood ecosystem; 10 to 230 times greater than in other ecosystems. A saturating exponential model (y = a(1–e−kx) + c) produced the smallest residual mean squares in predicting overstory biomass (R2 = 0.822) and annual biomass increment (R2 = 0.847) from potential net N mineralization. Maximum overstory biomass and biomass increment predicted from this equation were 247 t•ha−1 and 3.7 t•ha−1, respectively. In addition, laboratory net N mineralization potentials were highly correlated with annual rates of N mineralization determined by insitu incubation (r2 = 0.849). Overstory biomass and woody biomass increment were poorly correlated with potential net nitrification. The exponential function used to predict biomass increment from N mineralization suggests that the productivity of some northern hardwood forests in northern Lower Michigan is not limited by N availability.

2020 ◽  
Author(s):  
Alexander C Helman ◽  
Matthew C Kelly ◽  
Mark D Rouleau ◽  
Yvette L Dickinson

Abstract Managing northern hardwood forests using high-frequency, low-intensity regimes, such as single-tree selection, favors shade-tolerant species and can reduce tree species diversity. Management decisions among family forest owners (FFO) can collectively affect species and structural diversity within northern hardwood forests at regional scales. We surveyed FFOs in the Western Upper Peninsula of Michigan to understand likely future use of three silvicultural treatments—single-tree selection, shelterwood, and clearcut. Our results indicate that FFOs were most likely to implement single-tree selection and least likely to implement clearcut within the next 10 years. According to logistic regression, prior use of a treatment and perceived financial benefits significantly increased the odds for likely use for all three treatments. Having received professional forestry assistance increased likely use of single-tree selection but decreased likely use of shelterwood. We discuss these results within the context of species diversity among northern hardwood forests throughout the region.


Ecosystems ◽  
2019 ◽  
Vol 23 (3) ◽  
pp. 541-554
Author(s):  
Adam Gorgolewski ◽  
Philip Rudz ◽  
Trevor Jones ◽  
Nathan Basiliko ◽  
John Caspersen

2010 ◽  
Vol 40 (3) ◽  
pp. 436-444 ◽  
Author(s):  
Frank S. Gilliam ◽  
Adam Cook ◽  
Salina Lyter

This study examined effects of soil freezing on N dynamics in soil along an N processing gradient within a mixed hardwood dominated watershed at Fernow Experimental Forest, West Virginia. Sites were designated as LN (low rates of N processing), ML (moderately low), MH (moderately high), and HN (high). Soils underwent three 7-day freezing treatments (0, –20, or –80 °C) in the laboratory. Responses varied between temperature treatments and along the gradient. Initial effects differed among freezing treatments for net N mineralization, but not nitrification, in soils across the gradient, generally maintained at LN < ML ≤ MH < HN for all treatments. Net N mineralization potential was higher following freezing at –20 and –80 °C than control; all were higher than at 0 °C. Net nitrification potential exhibited similar patterns. LN was an exception, with net nitrification low regardless of treatment. Freezing response of N mineralization differed greatly from that of nitrification, suggesting that soil freezing may decouple two processes of the soil N cycle that are otherwise tightly linked at our site. Results also suggest that soil freezing at temperatures commonly experienced at this site can further increase net nitrification in soils already exhibiting high nitrification from N saturation.


Ecology ◽  
1964 ◽  
Vol 45 (3) ◽  
pp. 448-459 ◽  
Author(s):  
Edward Flaccus ◽  
Lewis F. Ohmann

1999 ◽  
Vol 29 (4) ◽  
pp. 497-508 ◽  
Author(s):  
Kiyokazu Ohrui ◽  
Myron J Mitchell ◽  
Joseph M Bischoff

Within a forest ecosystem in the Adirondack Mountains of New York, net N mineralization and nitrification rates were measured at different landscape positions (zones). Net N mineralization rates (0-15 cm depth) were less (39 kg N·ha-1 per year) within a wetland without alder and with a coniferous overstory than an upland conifer zone (82 kg N·ha-1 per year) and an upland hardwood zone (107 kg N·ha-1 per year). Net N mineralization rates (39 to 82 kg N·ha-1 per year) and the forest floor N concentrations (2.3 to 2.5%) were higher than values reported (1.2-29 kg N·ha-1 and 1.1-2.12%, respectively) for other spruce forests. The net nitrification rates were higher at the upland hardwood zone (29 kg N·ha-1 per year) than the upland conifer zone (2 kg N·ha-1 per year). The wetland conifer zone without alders had an intermediate rate of net nitrification (13 kg N·ha-1 per year) compared with the upland zones. The presence of white alder (Alnus incana (L.) Moench) in the wetland increased the NO3- content and net nitrification rate of the soil.


2002 ◽  
Vol 32 (9) ◽  
pp. 1562-1576 ◽  
Author(s):  
Gregory G McGee ◽  
Robin W Kimmerer

The objective of this study was to assess the influence of substrate heterogeneity on epiphytic bryophyte communities in northern hardwood forests of varying disturbance histories. Specifically, we compared bryophyte abundance (m2·ha–1) and community composition among partially cut; maturing, 90- to 100-year-old, even-aged; and old-growth northern hardwood stands in Adirondack Park, New York, U.S.A. Total bryophyte cover from 0 to 1.5 m above ground level on trees [Formula: see text]10 cm diameter at breast height (DBH) did not differ among the three stand types. However, bryophyte community composition differed among host tree species and among stand types. Communities in partially cut and maturing stands were dominated by xerophytic bryophytes (Platygyrium repens, Frullania eboracensis, Hypnum pallescens, Brachythecium reflexum, Ulota crispa), while old-growth stands contained a greater representation of calcicoles and mesophytic species (Brachythecium oxycladon, Anomodon rugelii, Porella platyphylloidea, Anomodon attenuatus, Leucodon brachypus, Neckera pennata). This mesophyte-calcicole assemblage occurred in all stand types but was limited by the abundance of large-diameter (>50 cm DBH), thick-barked, hardwood host trees (Acer saccharum Marsh., Tilia americana L., Fraxinus americana L.). This study suggested that epiphytic bryophyte diversity can be sustained and enhanced in managed northern hardwood forests by maintaining host tree species diversity and retaining large or old, thick-barked residual hardwood stems when applying even-aged and uneven-aged silviculture systems.


1992 ◽  
Vol 22 (11) ◽  
pp. 1761-1769 ◽  
Author(s):  
Kurt S. Pregitzer ◽  
Andrew J. Burton ◽  
Glenn D. Mroz ◽  
Hal O. Liechty ◽  
Neil W. MacDonald

Emissions of sulfur (S) and nitrogen (N) oxides in the midwestern and northeastern United States result in pronounced regional gradients of acidic deposition. The objective of this study was to determine the extent to which atmospheric deposition alters the uptake and cycling of S and N in five analogous northern hardwood forests located along one of the most pronounced regional gradients of SO42−-S and NO3−-N deposition in the United States. We tested the hypothesis that acidic deposition would alter foliar S and N ratios and nutrient cycling in aboveground litter fall. Sulfate in both wet deposition and throughfall increased by a factor of two across the 800-km deposition gradient. The July concentration of S in sugar maple (Acersaccharum Marsh.) leaves increased from about 1600 μg•g−1 at the northern research sites to 1800–1900 μg•g−1 at the southern sites. Differences in leaf litter S concentration were even more pronounced (872–1356 μg•g−1), and a clear geographic trend was always apparent in litter S concentration. The 3-year average S content of leaf litter was 63% greater at the southern end of the pollution gradient. Nitrate and total N deposition were also significantly greater at the southern end of the gradient. The concentration of N in both summer foliage and leaf litter was not correlated with N deposition, but the content of N in leaf litter was significantly correlated with N deposition. The molar ratios of S:N in mid-July foliage and leaf litter increased as atmospheric deposition of SO42−-S increased. Ratios of S:N were always much greater in leaf litter than in mid-July foliage. The molar ratios of S:N retranslocated from the canopies of these northern hardwood forests were less than those in mid-July foliage or litter fall and showed no geographic trend related to deposition, suggesting that S and N are retranslocated in a relatively fixed proportion. Significant correlations between SO42−-S deposition and foliar S concentration, S cycling, and the molar ratio of S:N in foliage suggest that sulfate deposition has altered the uptake and cycling of S in northern hardwood forests of the Great Lakes region.


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