Factors controlling denitrification rates in upland and swamp forests

1992 ◽  
Vol 22 (11) ◽  
pp. 1597-1604 ◽  
Author(s):  
Amy G. Merrill ◽  
Donald R. Zak

Spatial patterns of denitrification and temporal variation in the factors controlling this process were studied in three forested ecosystems in northern Lower Michigan. Two forest stands were randomly located within each of two well-drained upland forests (sugar maple–red oak/Maianthemum and sugar maple–basswood/Osmorhiza ecosystems) and one swamp ecosystem (silver maple–red maple/Osmunda ecosystem). Potential N mineralization, nitrification, and microbial respiration were measured in each forest stand using a 33-week laboratory incubation. Factors controlling denitrification were investigated in each ecosystem by treating soil samples with factorial combinations of NO3−, C, and Ar (anaerobic conditions). We also investigated the separate production of N2 and N2O during denitrification, and the factors controlling these fluxes, in a different experiment. Seasonal patterns of denitrification were quantified using an intact soil core method. Potential nitrification and microbial respiration were consistently highest in the swamp forest and lowest in the sugar maple–red oak/Maianthemum ecosystem (582 vs. 3 μg NO3−-N•g−1 and 5275 vs. 1254 μg CO2-C•g−1, respectively). Nitrate availability was the most important factor controlling denitrification in the swamp ecosystem, whereas increased soil water content resulted in the greatest response in the upland forests. Although NO3− significantly increased denitrification in the upland ecosystems, water additions elicited an even greater response. In addition, N2O production in the upland forests accounted for 70 to 90% of the total gaseous N loss; N2O accounted for only 25% of this loss in the swamp forest. Mean denitrification (intact soil cores) in the sugar maple–red oak/Maianthemum ecosystem (12 μg N2O-N•m−2•d−1) was significantly lower than rates measured in the sugar maple–bass-wood/Osmorhiza and silver maple–red maple/Osmunda ecosystems (24 and 39 μg N2O-N•m−2•d−1, respectively). Denitrification reached a maximum during June and July in the sugar maple–basswood/Osmorhiza ecosystem, whereas peaks occurred in May and September in the silver maple–red maple/Osmunda ecosystem. Denitrification in the sugar maple–red oak/Maianthemum forest was variable throughout the year and consistently low. Although variability was high, results suggest that denitrification and the factors controlling this process can be predicted using the spatial distribution of ecosystems.

1996 ◽  
Vol 13 (4) ◽  
pp. 182-188 ◽  
Author(s):  
Patrick J. Guertin ◽  
C. W. Ramm

Abstract Five-year diameter growth, basal area growth, and mortality for five upland hardwood species in northern Lower Michigan were compared to projections from Lake States TWIGS. The species studied were northern red oak, white oak, other red oak (pin oak and black oak combined), sugar maple, and red maple. The validation data consisted of individual tree measurements from 44 stands across 10 ecological land types on the Manistee National Forest. The stands were measured in 1986 and 1991; during this time interval stands experienced a drought and outbreaks of leaf defoliators. For individual dbh classes, 5 yr diameter growth was predicted within ± 0.3 in. for all species. Mean errors for BA projections were within ± 5 ft²/ac for all species, and mean error for trees/ac ranged from - 33 for other red oak to + 16 for sugar maple. Although precision was variable, Lake States TWIGS provided accurate predictions of 5 yr diameter growth for the five species tested. Projections of mortality were less accurate. North. J. Appl. For. 13(4):00-00.


1987 ◽  
Vol 5 (4) ◽  
pp. 173-175
Author(s):  
Bruce R. Roberts ◽  
Virginia M. Schnipke

Relative water demand, RWD, of 2-year-old containerized seedlings of red maple (Acer rubrum L.), sugar maple (A. saccharum Marsh.), silver maple (A. saccharinum L.), Norway Maple (A. platanoides L.) and boxelder (A. negundo L.) was determined by comparing potential evapotranspiration rates and actual water consumption values with growth rates for each species. Based on differences in growth rate, each species was determined to be either fast growing (red maple, silver maple, boxelder) or slow growing (sugar maple, Norway maple). Fast growing species used the most water over the 3-month experimental period (June-August), and had the higher RWD. The actual irrigation demand for each species was closely correlated with monthly potential evapotranspiration rates as determined by the Thornthwaite equation.


1999 ◽  
Vol 16 (3) ◽  
pp. 144-150 ◽  
Author(s):  
David W. McGill ◽  
Robert Rogers ◽  
A. Jeff Martin ◽  
Paul S. Johnson

Abstract Stocking equations and charts for stands dominated by northern red oak were developed from data collected on 66 plots in 52 northern red oak stands in Wisconsin. In all plots, northern red oak was the dominant species. Tolerant species such as sugar maple and red maple usually formed a subcanopy. We used the tree-area ratio method for measuring stocking. However, we treated the tolerant subcanopy as a separate component of stocking. This facilitated defining average maximum relative stand density (100% stocking)for the main canopy or the main canopy and subcanopy combined.This approach is based on the assumption that shade tolerant species can exploit resources in spatial strata that are unexploited by the mid-tolerant red oak. The resulting stocking equations and charts can provide an objective basis for evaluating stocking of northern red oak stands in Wisconsin.North. J. Appl. For. 16(3):144-150.


1996 ◽  
Vol 10 (1) ◽  
pp. 210-216 ◽  
Author(s):  
She-Kong Chong ◽  
Suling Zhao ◽  
Brian P. Klubek

Various samplers have been developed for taking intact soil cores. Very often, the sampler was used once or twice to take only a few soil cores then it became either obsolete or a burden for maintenance and storage. An economic portable hand-operated soil core sampler was developed to obtain large soil cores with a diameter of 19 cm and a length of 120 cm. The quality of large soil cores was evaluated and compared with that obtained from short cores from each soil horizon. In addition, the large intact column was used to evaluate atrazine transport under the saturated condition. Results showed that the hydraulic conductivity of the large cores were of the same magnitude as that of short cores, except for the A horizon; the hydraulic conductivity of the large cores was about 10 times greater than the short cores. Even though the sampling procedure is labor intensive, the soil sampler has the flexibility to collect different size soil cores and can be constructed at a very low cost (less than $200 including labor). Lastly, the sampler is maintenance free and can be stored easily in a limited space.


2014 ◽  
Vol 11 (6) ◽  
pp. 8399-8442 ◽  
Author(s):  
C. Werner ◽  
K. Reiser ◽  
M. Dannenmann ◽  
L. B. Hutley ◽  
J. Jacobeit ◽  
...  

Abstract. Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in Northern Australia. However, how such changes affect the soil–atmosphere exchange of nitrous oxide (N2O), nitric oxide (NO) and dinitrogen (N2) is still not well explored. By incubating intact soil cores from four sites (3 savanna, 1 pasture) under controlled soil temperatures (ST) and soil moisture (SM) we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2). Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emission were very low (<7.0 ± 5.0 μg NO-N m−2 h−1; <0.0 ± 1.4 μg N2O-N m−2 h−1) or in case of N2O, even a net soil uptake was observed. Substantial NO (max: 306.5 μg N m−2 h−1) and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m−2 h−1) were recorded following soil wetting, but these pulses were short-lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was dominated by N2 emissions (82.4–99.3% of total N lost), although NO emissions contributed almost 43.2% at 50% SM and 30 °C ST. N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. Emissions were controlled by SM and ST for N2O and CO2, ST and pH for NO, and SM and pH for N2.


2014 ◽  
Vol 11 (21) ◽  
pp. 6047-6065 ◽  
Author(s):  
C. Werner ◽  
K. Reiser ◽  
M. Dannenmann ◽  
L. B. Hutley ◽  
J. Jacobeit ◽  
...  

Abstract. Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in northern Australia. However, how such changes affect the soil–atmosphere exchange of nitrous oxide (N2O), nitric oxide (NO) and dinitrogen (N2) is still not well explored. By incubating intact soil cores from four sites (three savanna, one pasture) under controlled soil temperatures (ST) and soil moisture (SM) we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2). Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emissions were very low (<7.0 ± 5.0 μg NO-N m−2 h−1; <0.0 ± 1.4 μg N2O-N m−2 h−1) or in the case of N2O, even a net soil uptake was observed. Substantial NO (max: 306.5 μg N m−2 h−1) and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m−2 h−1) were recorded following soil wetting, but these pulses were short lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was generally dominated by N2 emissions (82.4–99.3% of total N lost), although NO emissions contributed almost 43.2% to the total atmospheric nitrogen loss at 50% SM and 30 °C ST incubation settings (the contribution of N2 at these soil conditions was only 53.2%). N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. By using a conservative upscale approach we estimate total annual emissions from savanna soils to average 0.12 kg N ha−1 yr−1 (N2O), 0.68 kg N ha−1 yr−1 (NO) and 6.65 kg N ha−1 yr−1 (N2). The analysis of long-term SM and ST records makes it clear that extreme soil saturation that can lead to high N2O and N2 emissions only occurs a few days per year and thus has little impact on the annual total. The potential contribution of nitrogen released due to pulse events compared to the total annual emissions was found to be of importance for NO emissions (contribution to total: 5–22%), but not for N2O emissions. Our results indicate that the total gaseous release of nitrogen from these soils is low and clearly dominated by loss in the form of inert nitrogen. Effects of seasonally varying soil temperature and moisture were detected, but were found to be low due to the small amounts of available nitrogen in the soils (total nitrogen <0.1%).


1990 ◽  
Vol 7 (4) ◽  
pp. 163-168 ◽  
Author(s):  
David B. Kittredge ◽  
P. Mark S. Ashton

Abstract A regeneration survey in southern New England in three different cover types indicated that most of the seedlings present were less than 19.7 in. in height. Although red oak was a principal component of the overstory, it represented a small proportion of regeneration. Black birch and red maple were common regeneration components. There was a general relationship between overstory density and the amount of regeneration. To obtain natural regeneration, a general broad optimum range of overstory densities between 20-80 ft²/ac of basal area is suggested. Successful red oak and sugar maple regeneration was obtained with overstory densities of these species between 20-40 ft²/ac. A higher proportion of these species did not result in more regeneration. White pine regeneration was closely related to the amount of white pine in the overstory, however. The density of mountain laurel seemed to have little effect on the establishment of regeneration. The greater the length of time since last harvest, the more oak seedlings would be present in hard-wood stands. The opposite was true for red maple, black birch, and hemlock. North. J. Appl For. 7:163-168, December 1990.


1991 ◽  
Vol 9 (1) ◽  
pp. 1-4
Author(s):  
W. Clark Ashby ◽  
Damian F. Bresnan ◽  
Carl A. Huettemen ◽  
John E. Preece ◽  
Paul L. Roth

Abstract Silver maple (Acer saccharinum L.) goes dormant in the autumn and is greatly delayed in bud break unless the buds are exposed to prolonged low temperature. Approximately 1000 hours below 4°C (39°F) under natural conditions (early March in southern Illinois) will bring about bud break 2 to 3 weeks after juvenile plants are put under favorable growing conditions. Chilling in a dark cold room at 4°C (39°F) separated from natural changes required a greater number of hours, approximately 2000, for a similar response. Bud break for subterminal buds was earlier than for terminal buds on insufficiently chilled stem segments or larger plantlets. Terminal buds broke first with longer chilling periods. Rooted cuttings from adult trees had a greater chilling requirement than juvenile plant material, either micropropagated plantlets or segments from shoots. No geographic or provenance variation in response to chilling was observed within 11 provenances ranging from Mississippi to central Ontario to New Hampshire to West Virginia. Silver maple was similar to sugar maple and basswood in its chilling requirement. It was unlike red maple which has a chilling requirement in some but not all parts of its range.


2020 ◽  
Vol 52 (3) ◽  
pp. 292-297
Author(s):  
Tara Lee Bal ◽  
Katherine Elizabeth Schneider ◽  
Dana L. Richter

1990 ◽  
Vol 20 (9) ◽  
pp. 1479-1484 ◽  
Author(s):  
F. A. Bazzaz ◽  
J. S. Coleman ◽  
S. R. Morse

We examined how elevated CO2 affected the growth of seven co-occurring tree species: American beech (Fagusgrandifolia Ehrh.), paper birch (Betulapapyrifera Marsh.), black cherry (Prunusserotina Ehrh.), white pine (Pinusstrobus L.), red maple (Acerrubrum L.), sugar maple (Acersaccharum Marsh.), and eastern hemlock (Tsugacanadensis (L.) Carr). We also tested whether the degree of shade tolerance of species and the age of seedlings affected plant responses to enhanced CO2 levels. Seedlings that were at least 1 year old, for all species except beech, were removed while dormant from Harvard Forest, Petersham, Massachusetts. Seeds of red maple and paper birch were obtained from parent trees at Harvard Forest, and seeds of American beech were obtained from a population of beeches in Nova Scotia. Seedlings and transplants were grown in one of four plant growth chambers for 60 d (beech, paper birch, red maple, black cherry) or 100 d (white pine, hemlock, sugar maple) under CO2 levels of 400 or 700 μL•L−1. Plants were then harvested for biomass and growth determinations. The results showed that the biomass of beech, paper birch, black cherry, sugar maple, and hemlock significantly increased in elevated CO2, but the biomass of red maple and white pine only marginally increased in these conditions. Furthermore, there were large differences in the magnitude of growth enhancement by increased levels of CO2 between species, so it seems reasonable to predict that one consequence of rising levels of CO2 may be to increase the competitive ability of some species relative to others. Additionally, the three species exhibiting the largest increase in growth with increased CO2 concentrations were the shade-tolerant species (i.e., beech, sugar maple, and hemlock). Thus, elevated CO2 levels may enhance the growth of relatively shade-tolerant forest trees to a greater extent than growth of shade-intolerant trees, at least under the light and nutrient conditions of this experiment. We found no evidence to suggest that the age of tree seedlings greatly affected their response to elevated CO2 concentrations.


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