Variation in foliar nitrogen concentration by forest type and climatic gradients in North America

1993 ◽  
Vol 23 (8) ◽  
pp. 1587-1602 ◽  
Author(s):  
Xiwei Yin
Keyword(s):  
Forest Type ◽  
Light Availability ◽  
Net Photosynthesis ◽  
Deciduous Forests ◽  
Coniferous Forests ◽  
Mean Annual Temperature ◽  
Data Set ◽  
Foliar Nitrogen ◽  
Foliar N ◽  
July Temperature

Published data were used to explore variation in foliar nitrogen (N) concentration in relation to forest type, foliar life-span, latitude, mean January temperature, mean July temperature, mean annual temperature, annual precipitation, annual actual evapotranspiration, mean monthly solar radiation in foliar lifetime, and annual soil water deficit. The hypothesis was that foliar N concentration integrating carbon and N links should be closely correlated with climatic constraints at a broad regional scale. The data set included 49 deciduous broadleaf forests and 58 evergreen coniferous forests distributed across North America. Foliar N concentrations were correlated primarily with mean July temperature for deciduous forests (negative), but also with mean January temperature, mean annual temperature, latitude, and solar radiation for coniferous forests (negative quadratic). These correlations also existed for individual forest groups defined by N requirement or genera of dominant species. Deciduous forests nearly always had higher foliar N concentrations than coniferous forests for given climates, but differences diminished in warm climates. Mean July temperature and latitude each explained 69% of variance in foliar N concentrations of deciduous and coniferous forests, respectively, and together explained 90% of variance in the total data set. Independent data confirmed these correlations. It is proposed that foliar N concentrations of deciduous forests increase with decreasing mean July temperature because (i) N may be passively concentrated due to low temperatures reducing net photosynthesis and foliar life-spans, but not N availability; and (ii) N may be actively concentrated as a plant adaptation to counteract suboptimum temperature effects on net photosynthesis. In coniferous forests, N may concentrate in foliage with decreasing but sufficiently high light availability and temperature, when foliar life-spans are fairly constant, and where soil is rarely frozen. As light availability and temperature fall below a limit, conifer foliar N concentrations may decrease due to combined effects of prolonged foliar life-spans and restricted N uptake.

scholarly journals Nitrogen load and forest type determine the soil emission of nitrogen oxides (NO and N<sub>2</sub>O)

2006 ◽  
Vol 3 (3) ◽  
pp. 837-869 ◽  
Author(s):  
K. Pilegaard ◽  
U. Skiba ◽  
P. Ambus ◽  
C. Beier ◽  
N. Brüggemann ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Forest Type ◽  
Regional Scale ◽  
N2o Emission ◽  
N Deposition ◽  
Deciduous Forests ◽  
Coniferous Forests ◽  
Litter Layer ◽  
N2o Production ◽  
No Emissions

Abstract. Soil emissions of NO and N2O were measured continuously at high frequency for more than one year at 15 European forest sites as part of the EU-funded project NOFRETETE. The locations represent different forest types (coniferous/deciduous) and different nitrogen loads. Geographically they range from Finland in the north to Italy in the south and from Hungary in the east to Scotland in the west. The highest NO emissions were observed from coniferous forests, whereas the lowest NO emissions were observed from deciduous forests. The NO emissions from coniferous forests were highly correlated with N-deposition. The site with the highest average annual emission (82 μg NO-Nm−2 h−1) was a spruce forest in South-Germany (Höglwald) receiving an annual N-deposition of 2.9 gm−2. NO emissions close to the detection limit were observed from a pine forest in Finland where the N-deposition was 0.2 g N m−2 y−1. No significant correlation between N2O emission and N-deposition was found. The highest average annual N2O emission (20 μg N2O-Nm−2 h−1) was found in an oak forest in the Mátra mountains (Hungary) receiving an annual N-deposition of 1.6 gm−2. N2O emission was significantly negatively correlated with the C/N ratio. The difference in N-oxide emissions from soils of coniferous and deciduous forests may partly be explained by differences in N-deposition rates and partly by difference in characteristics of the litter layer and soil. NO was mainly derived from nitrification whereas N2O was mainly derived from denitrification. In general, soil moisture is lower at coniferous sites (at least during spring time) and the litter layer of coniferous forests is thick and well aerated favouring nitrification and thus release of NO. Conversely, the higher rates of denitrification in deciduous forests due to a compact and moist litter layer lead to N2O production and NO consumption in the soil. The two factors soil moisture and soil temperature are often explaining most of the temporal variation within a site. When comparing annual emissions on a regional scale, however, factors such as nitrogen deposition and forest and soil type become much more important.

Nitrogen use efficiency in relation to forest type, N expenditure, and climatic gradients in North America

1994 ◽  
Vol 24 (3) ◽  
pp. 533-541 ◽  
Author(s):  
Xiwei Yin
Keyword(s):  
North America ◽  
Nitrogen Use Efficiency ◽  
Forest Type ◽  
Light Availability ◽  
Deciduous Forests ◽  
Leaf Fall ◽  
Forest Types ◽  
Nitrogen Use ◽  
Evergreen Forests ◽  
Use Efficiency

Forest nitrogen use efficiency (NUE) values are often compared along N-availability gradients or between forest types, without adjustment for climate. In this study, NUE (leaf-fall mass/leaf-fall N) was examined with concurrent data on forest type, N expenditure (leaf-fall N), foliar life-span, and major climatic gradients. The hypotheses were that (1) NUE is negatively correlated with N expenditure, (2) NUE is positively correlated with climatic factors such as temperature and light availability, and (3) NUE differs between deciduous and evergreen forests. The data set included 76 deciduous broadleaf forests, 52 evergreen coniferous forests, and 6 mixed forests in North America. All three hypotheses are supported by best-fit models. NUE decreases by about 30% for each doubling of N expenditure for both deciduous and evergreen forests. It increases over 50% in deciduous forests and nearly triples in evergreen forests across the climate data range. Evergreen forests tend to have higher NUEs than deciduous forests only in areas with relatively high temperatures and light availability. This climate–forest type interaction is attributed to contrasts between the forest types in terms of growth period, and regional patterns of foliar N concentration and N resorption.

Evaluation of the CONSUME and FOFEM fuel consumption models in pine and mixed hardwood forests of the eastern United States

2014 ◽  
Vol 44 (7) ◽  
pp. 784-795 ◽  
Author(s):  
Susan J. Prichard ◽  
Eva C. Karau ◽  
Roger D. Ottmar ◽  
Maureen C. Kennedy ◽  
James B. Cronan ◽  
...  
Keyword(s):  
United States ◽  
Fuel Consumption ◽  
Prescribed Burning ◽  
Forest Type ◽  
Fire Effects ◽  
Eastern United States ◽  
Validation Data ◽  
Data Set ◽  
Predicted Values ◽  
Fine Fuels

Reliable predictions of fuel consumption are critical in the eastern United States (US), where prescribed burning is frequently applied to forests and air quality is of increasing concern. CONSUME and the First Order Fire Effects Model (FOFEM), predictive models developed to estimate fuel consumption and emissions from wildland fires, have not been systematically evaluated for application in the eastern US using the same validation data set. In this study, we compiled a fuel consumption data set from 54 operational prescribed fires (43 pine and 11 mixed hardwood sites) to assess each model’s uncertainties and application limits. Regions of indifference between measured and predicted values by fuel category and forest type represent the potential error that modelers could incur in estimating fuel consumption by category. Overall, FOFEM predictions have narrower regions of indifference than CONSUME and suggest better correspondence between measured and predicted consumption. However, both models offer reliable predictions of live fuel (shrubs and herbaceous vegetation) and 1 h fine fuels. Results suggest that CONSUME and FOFEM can be improved in their predictive capability for woody fuel, litter, and duff consumption for eastern US forests. Because of their high biomass and potential smoke management problems, refining estimates of litter and duff consumption is of particular importance.

scholarly journals Evaluation of coral reef carbonate production models at a global scale

2015 ◽  
Vol 12 (5) ◽  
pp. 1339-1356 ◽  
Author(s):  
N. S. Jones ◽  
A. Ridgwell ◽  
E. J. Hendy
Keyword(s):  
Coral Reef ◽  
Predictive Power ◽  
Numerical Models ◽  
Coral Cover ◽  
Light Availability ◽  
Global Scale ◽  
Data Set ◽  
Carbonate Production ◽  
Future Global Warming ◽  
Atmospheric Co2 Concentrations

Abstract. Calcification by coral reef communities is estimated to account for half of all carbonate produced in shallow water environments and more than 25% of the total carbonate buried in marine sediments globally. Production of calcium carbonate by coral reefs is therefore an important component of the global carbon cycle; it is also threatened by future global warming and other global change pressures. Numerical models of reefal carbonate production are needed for understanding how carbonate deposition responds to environmental conditions including atmospheric CO2 concentrations in the past and into the future. However, before any projections can be made, the basic test is to establish model skill in recreating present-day calcification rates. Here we evaluate four published model descriptions of reef carbonate production in terms of their predictive power, at both local and global scales. We also compile available global data on reef calcification to produce an independent observation-based data set for the model evaluation of carbonate budget outputs. The four calcification models are based on functions sensitive to combinations of light availability, aragonite saturation (Ωa) and temperature and were implemented within a specifically developed global framework, the Global Reef Accretion Model (GRAM). No model was able to reproduce independent rate estimates of whole-reef calcification, and the output from the temperature-only based approach was the only model to significantly correlate with coral-calcification rate observations. The absence of any predictive power for whole reef systems, even when consistent at the scale of individual corals, points to the overriding importance of coral cover estimates in the calculations. Our work highlights the need for an ecosystem modelling approach, accounting for population dynamics in terms of mortality and recruitment and hence calcifier abundance, in estimating global reef carbonate budgets. In addition, validation of reef carbonate budgets is severely hampered by limited and inconsistent methodology in reef-scale observations.

scholarly journals Distribution and diversity of myxomycetes in Tiantangzhai National Forest Park, China

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12059
Author(s):  
Min Li ◽  
Gaowei Wang ◽  
Yang Gao ◽  
Mingzhu Dou ◽  
Ziqi Wang ◽  
...  
Keyword(s):  
Water Retention ◽  
Forest Type ◽  
Terrestrial Ecosystems ◽  
Coniferous Forests ◽  
National Forest ◽  
Moist Chamber ◽  
Mixed Forests ◽  
Forest Park ◽  
Main Factor

Although myxomycetes are ubiquitous in terrestrial ecosystems, studies on their distribution and diversity in subtropical humid forests are still lacking. Field collections and moist chamber cultures were conducted from May to October within a two-year period in the Tiantangzhai National Forest Park of China. A total of 1,492 records representing 73 species belonging to 26 genera were obtained, of which 243 records/37 species were from field collections, and 1,249 records/52 species were from moist chamber cultures. Among the specimens obtained by culturing, 896 records/38 species and 353 records/37 species were obtained from living bark and ground litter, respectively. ANOVA showed that the sampling months had significant impacts on collection of myxomycetes from field and those that inhabit litter. An LEfSe analysis indicated that Arcyria was significantly abundant in August, while Stemonitis and Physarum were more abundant in July when collected from field. An RDA analysis showed that temperature was the main factor that affected the litter-inhabiting myxomycetes. The ANOVA indicated that forest type was the significant factor for bark-inhabiting myxomycetes. Diderma effusum was primarily obtained from mixed forests, while Clastoderma debaryanum and Colloderma oculatum were more common in coniferous forests. The RDA analysis indicated that the vegetation, pH, water retention, and elevation were the primary factors that affected the bark-inhabiting myxomycetes.

scholarly journals Comparing Grazed and Ungrazed Forests in Kansas

1998 ◽  
Vol 15 (4) ◽  
pp. 216-221 ◽  
Author(s):  
Thomas L. Schmidt ◽  
Mark H. Hansen
Keyword(s):  
Decision Making ◽  
Forest Type ◽  
Deciduous Forests ◽  
Decision Making Process ◽  
Juniperus Virginiana ◽  
Bare Ground ◽  
Eastern Redcedar ◽  
Growing Stock ◽  
Hardwood Species ◽  
Stock Volume

Abstract Differences between grazed and ungrazed forestlands in Kansas were investigated based on a statewide sample of all forestlands. Grazing forestlands was found to have a significant relationship to the quality and quantity of trees on forestlands, as seen in lower levels of total volume and growing-stock volume when compared to ungrazed forestlands. In addition, grazed forestlands showed lower average basal areas, younger average stand ages, lower potential productivities, and increased percentages of bare ground. Compared to forestlands without grazing, forestlands with grazing had higher levels of eastern redcedar (Juniperus virginiana L.) seedling regeneration and lower levels of preferred hardwood species regeneration in several forest type groups. Land managers can use these results in their decision-making process concerning whether to graze their deciduous forests. North. J. Appl. For. 15(4):216-221.

scholarly journals Inferring late-Holocene climate in the Ecuadorian Andes using a chironomid-based temperature inference model

2016 ◽  
Vol 12 (5) ◽  
pp. 1263-1280 ◽  
Author(s):  
Frazer Matthews-Bird ◽  
Stephen J. Brooks ◽  
Philip B. Holden ◽  
Encarni Montoya ◽  
William D. Gosling
Keyword(s):  
Bayesian Method ◽  
Mean Squared Error ◽  
Weighted Averaging ◽  
Mean Annual Temperature ◽  
Calibration Data ◽  
Tropical Andes ◽  
Data Set ◽  
Inference Models ◽  
Calibration Data Set ◽  
Study Sites

Abstract. Presented here is the first chironomid calibration data set for tropical South America. Surface sediments were collected from 59 lakes across Bolivia (15 lakes), Peru (32 lakes), and Ecuador (12 lakes) between 2004 and 2013 over an altitudinal gradient from 150 m above sea level (a.s.l) to 4655 m a.s.l, between 0–17° S and 64–78° W. The study sites cover a mean annual temperature (MAT) gradient of 25 °C. In total, 55 chironomid taxa were identified in the 59 calibration data set lakes. When used as a single explanatory variable, MAT explains 12.9 % of the variance (λ1/λ2 =  1.431). Two inference models were developed using weighted averaging (WA) and Bayesian methods. The best-performing model using conventional statistical methods was a WA (inverse) model (R2jack =  0.890; RMSEPjack =  2.404 °C, RMSEP – root mean squared error of prediction; mean biasjack =  −0.017 °C; max biasjack =  4.665 °C). The Bayesian method produced a model with R2jack =  0.909, RMSEPjack =  2.373 °C, mean biasjack =  0.598 °C, and max biasjack =  3.158 °C. Both models were used to infer past temperatures from a ca. 3000-year record from the tropical Andes of Ecuador, Laguna Pindo. Inferred temperatures fluctuated around modern-day conditions but showed significant departures at certain intervals (ca. 1600 cal yr BP; ca. 3000–2500 cal yr BP). Both methods (WA and Bayesian) showed similar patterns of temperature variability; however, the magnitude of fluctuations differed. In general the WA method was more variable and often underestimated Holocene temperatures (by ca. −7 ± 2.5 °C relative to the modern period). The Bayesian method provided temperature anomaly estimates for cool periods that lay within the expected range of the Holocene (ca. −3 ± 3.4 °C). The error associated with both reconstructions is consistent with a constant temperature of 20 °C for the past 3000 years. We would caution, however, against an over-interpretation at this stage. The reconstruction can only currently be deemed qualitative and requires more research before quantitative estimates can be generated with confidence. Increasing the number, and spread, of lakes in the calibration data set would enable the detection of smaller climate signals.

Photosynthesis and physiological traits of evergreen broadleafed saplings during winter under different light environments in a temperate forest

2006 ◽  
Vol 84 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Yoshiyuki Miyazawa ◽  
Kihachiro Kikuzawa
Keyword(s):  
Temperate Forest ◽  
Light Availability ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Leaf Mass Per Area ◽  
Camellia Japonica ◽  
Leaf Mass ◽  
Unit Leaf ◽  
Canopy Trees ◽  
Photosynthetic Traits

Photosynthetic traits of the evergreen broadleafed species Camellia japonica L. and Quercus glauca Thunb. were continuously investigated during autumn and winter using saplings that grew in different light environments (gap, deciduous canopy understory, and evergreen canopy understory) in a temperate forest. Light-saturated rates of net photosynthesis in midwinter and spring were lower than those in autumn. Photosynthetic capacity, scaled to a common leaf temperature of 25 °C, increased or remained stable after autumn and then decreased in spring in most leaves. Photosynthetic traits per unit leaf area were different among leaves in different light environments of both Camellia and Quercus during most periods. However, photosynthetic traits per unit leaf mass did not differ among leaves in different light environments, suggesting that differences in photosynthetic traits were mainly due to different leaf mass per area among leaves. Photosynthetic rates under light availability typical in the environment were lower in winter than in autumn in leaves in the sun in a gap but were not different in leaves in the shade under evergreen canopy trees. Thus, the importance of winter carbon gain for annual carbon gain is small in leaves in a gap but is large in leaves under evergreen canopy trees.

Sequestration of carbon in the humus layer of Swedish forests — direct measurements

2009 ◽  
Vol 39 (5) ◽  
pp. 962-975 ◽  
Author(s):  
Björn Berg ◽  
Maj-Britt Johansson ◽  
Åke Nilsson ◽  
Per Gundersen ◽  
Lennart Norell
Keyword(s):  
Layer Thickness ◽  
Forest Type ◽  
C Sequestration ◽  
Rate Of Change ◽  
Kriging Interpolation ◽  
Data Set ◽  
C Storage ◽  
Humus Layer ◽  
Sequestration Rate ◽  
Storage Rate

To determine sequestration rates of carbon dioxide (CO2) we calculated the carbon (C) storage rate in humus layers of Swedish forests with Podsolic soils, which account for 14.2 × 106 ha of the 22.7 × 106 ha of forested land in Sweden. Our data set covered 41 years of humus inventories and mean humus layer thickness in 82 513 plots. We analysed three forest types: (i) all combinations of tree species, (ii) forests dominated (>70%) by Norway spruce ( Picea abies (L.) Karst.), and (iii) forests dominated (>70%) by Scots pine ( Pinus sylvestris L.). To relate changes in humus layer thickness to land area we used the intersections in 25 km × 25 km grids and used kriging interpolation, permitting calculations for each forest type. For each intersection mean humus thickness for each year was calculated and regressed against time to obtain the rate of change. This rate, humus bulk density, and humus C concentration were used to calculate sequestration rates. The mean sequestration rate was 251 kg C·ha–1·year–1, which is higher than theoretical values. The sequestration rate was positively related to temperature sum, albeit including effects of forest management. The pine-dominated forest type had a mean rate of 283 kg C·ha–1·year–1, and the spruce-dominated had a mean rate of 239 kg C·ha–1·year–1. Under similar site conditions, pine sequestered more C than spruce (difference of 71 kg C·ha–1·year–1; p < 0.0001), showing the importance of this type of ecosystem for C sequestration.

scholarly journals BLACK ALDER DOMINATED FOREST VEGETATION IN THE WESTERN PART OF CENTRAL SLOVAKIA – SPECIES COMPOSITION AND ECOLOGY

Hacquetia ◽  
2013 ◽  
Vol 12 (2) ◽  
pp. 23-37
Author(s):  
Richard Hrivnák ◽  
Jaroslav Košťál ◽  
Michal Slezák ◽  
Anna Petrášová ◽  
Melánia Feszterová
Keyword(s):  
Species Composition ◽  
Expert Knowledge ◽  
Light Availability ◽  
Principal Component ◽  
Environmental Parameters ◽  
Soil Surface ◽  
Open Water ◽  
Forest Vegetation ◽  
Data Set ◽  
Black Alder

Abstract In some regions of Slovakia, black alder forest vegetation has not been documented appropriately yet. This paper is the first vegetation study presenting the phytosociological data and measured environmental parameters from the western part of central Slovakia. The data set was classified by using a modified TWINSPAN algorithm, which allowed us to discern floristically and ecologically distinctive plant communities. They correspond to the associations Stellario nemorum-Alnetum glutinosae Lohmeyer 1957 (riparian alder vegetation on mesic to humid sites along small brooks) and Carici acutiformis-Alnetum glutinosae Scamoni 1935 (eutrophic black alder carr forests in the colline zone) with the variants of Ligustrum vulgare and Galium palustre. The community Carici elongatae-Alnetum glutinosae Schwickerath 1933 (mesotrophic to eutrophic alder carr vegetation growing on permanently waterlogged soils), documented only with two phytosociological relevés, was distinguished following expert knowledge. A floristic and ecological pattern of these associations is presented. The major compositional gradients were interpreted based on Ellenberg’s indicator values and the values of environmental variables recorded during the field sampling in the growing season 2011. The principal component analysis revealed the importance of soil moisture, light availability, portion of open water and soil surface for species composition variability at the association level, whereas the variants of Carici acutiformis-Alnetum glutinosae were sorted along the acidity gradient.

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