scholarly journals Viability of Litter-Stored Quercus falcata Michx. Acorns After Simulated Prescribed Winter Burns

1998 ◽  
Vol 8 (4) ◽  
pp. 199 ◽  
Author(s):  
MD Cain ◽  
MG Shelton
Keyword(s):  
Forest Floor ◽  
Prescribed Burning ◽  
Mineral Soil ◽  
Red Oak ◽  
Germination Test ◽  
Moist Sand ◽  
Sand Flats ◽  
Soil Interface

Partially stratified (11 days) southern red oak (Quercus falcata Michx.) acorns were placed at three depths in a reconstructed forest floor and subjected to simulated prescribed winter burns. Within the forest floor, acorns were placed within the L layer, at the upper-F/lower-F interface, and at the lower-F/mineral-soil interface. Winds for a backfire and headfire were generated by electric box-fans. After the burns, acorns were transferred to moist sand flats, stratified for an additional 16 days, then assessed for viability during a 45-day germination test. As depth within the forest floor increased, germinative capacity of acorns increased. All acorns placed within the L layer during prescribed burning failed to germinate. Germinative capacity of acorns placed at the upper-F/lower-F interface was lower (P=0.03) in the backfire (8.75%) than in the headfire (55.00%). At the lower-F/mineral-soil interface, there was no difference (P=0.09) in germinative capacity between backfire (92%) and headfire (89%), and their mean was no different (P=0.26) than the 93% achieved by unburned control acorns.

scholarly journals Thinning and Burning Effects on Long-Term Litter Accumulation and Function in Young Ponderosa Pine Forests

2020 ◽  
Vol 66 (6) ◽  
pp. 761-769
Author(s):  
Matt Busse ◽  
Ross Gerrard
Keyword(s):  
Ponderosa Pine ◽  
Forest Floor ◽  
Prescribed Burning ◽  
Mineral Soil ◽  
Pine Forests ◽  
Organic Layer ◽  
Litter Accumulation ◽  
Ponderosa Pine Forests ◽  
Essential Components

Abstract We measured forest-floor accumulation in ponderosa pine forests of central Oregon and asked whether selected ecological functions of the organic layer were altered by thinning and repeated burning. Experimental treatments included three thinning methods applied in 1989 (stem only, whole tree, no thin—control) in factorial combination with prescribed burning (spring 1991 and repeated in 2002; no burn—control). Forest-floor depth and mass were measured every 4–6 years from 1991 to 2015. Without fire, there was little temporal change in depth or mass for thinned (270 trees ha−1) and control (560–615 trees ha−1) treatments, indicating balanced litterfall and decay rates across these stand densities. Each burn consumed 50–70 percent of the forest floor, yet unlike thinning, postfire accumulation rates were fairly rapid, with forest-floor depth matching preburn levels within 15–20 years. Few differences in forest-floor function (litter decay, carbon storage, physical barrier restricting plant emergence, erosion protection) resulted from thinning or burning after 25 years. An exception was the loss of approximately 300 kg N ha−1 because of repeated burning, or approximately 13 percent of the total site N. This study documents long-term forest-floor development and suggests that common silvicultural practices pose few risks to organic layer functions in these forests. Study Implications: Mechanical thinning and prescribed fire are among the most widespread management practices used to restore forests in the western US to healthy, firewise conditions. We evaluated their effects on the long-term development of litter and duff layers, which serve dual roles as essential components of soil health and as fuel for potential wildfire. Our study showed that thinning and burning provided effective fuel reduction and resulted in no adverse effects to soil quality in dry ponderosa pine forests of central Oregon. Repeated burning reduced the site carbon and nitrogen pools approximately 9–13 percent, which is small compared to C located in tree biomass and N in mineral soil. Litter accumulation after burning was rapid, and we recommend burning on at least a 15–20-year cycle to limit its build-up.

Denitrification and nitrogen fixation in floodplain successional soils along the Tanana River, interior Alaska

1993 ◽  
Vol 23 (5) ◽  
pp. 956-963 ◽  
Author(s):  
K.M. Klingensmith ◽  
K. Van Cleve
Keyword(s):  
Nitrogen Fixation ◽  
Forest Floor ◽  
Nitrogenase Activity ◽  
Mineral Soil ◽  
White Spruce ◽  
Interactive Effects ◽  
Successional Stage ◽  
Alder Forest ◽  
Mineral Soils ◽  
Soil Interface

Forest floors and mineral soils from early (open willow), middle (poplar–alder), and late (white spruce) floodplain primary successional stages were examined for nitrogen fixation and denitrification. The acetylene-reduction and acetylene-inhibition techniques were used separately and in combination to measure nitrogenase and denitrification activities, both in laboratory and field studies. In situ N2O production was undetectable at all sites and during all sampling periods. Denitrifying activity measured in the field with acetylene amendments was low to undetectable, except after a brief flood in the open willow stand when N2O production ranged from undetectable to 34 ng N•cm−2•h−1 within the newly deposited alluvium–old mineral soil interface. Intact core assays also had low to undetectable denitrification activities; the highest activities (259 ng N•g−1 h−1) were measured in the poplar–alder forest floor in the fall. Laboratory studies showed that potential denitrification enzyme activity (DEA) was also greatest in the poplar–alder forest floor (4332 ng N•g−1•h−1), once again occurring in the fall. In early and midsuccessional stages, the interactive effects of temperature, carbon, and NO3− limited denitrification, yet even with the addition of the limiting amendments, low to undetectable DEA was observed in mineral soils. The later white spruce successional stage also had low to undetectable DEA, increasing only with the addition of the full DEA media and independent of temperature changes. Nonsymbiotic nitrogenase activities were highly variable, ranging from undetectable to 30 ng N•cm−2•h−1. Highest activities were seen in the open willow, newly deposited alluvium–old mineral soil interface immediately after a flood and approximately 1 month after the flood on the newly deposited silt surface. Only the white spruce forest floor had measurable nonsymbiotic nitrogenase activity at all sampling times. Alder root nodule nitrogenase activity showed no significant differences between sampling periods. The estimated annual nitrogen fixation rate of 164 kg N•ha−1 for alder root nodules is a substantial N contribution to the alder stand and to the floodplain ecosystem in general.

Clear-cutting, woody residue removal, and nonsymbiotic nitrogen fixation in forest soils of the Inland Pacific Northwest

1992 ◽  
Vol 22 (8) ◽  
pp. 1172-1178 ◽  
Author(s):  
M.F. Jurgensen ◽  
R.T. Graham ◽  
M.J. Larsen ◽  
A.E. Harvey
Keyword(s):  
Nitrogen Fixation ◽  
Pacific Northwest ◽  
Forest Floor ◽  
Prescribed Burning ◽  
Mineral Soil ◽  
Western Montana ◽  
Subalpine Fir ◽  
Residue Removal ◽  
Clear Cutting ◽  
Northern Idaho

The effect of clear-cutting and woody residue removal on soil nonsymbiotic nitrogen fixation, as estimated by the acetylene reduction technique, was investigated on a subalpine fir (Abieslasiocarpa (Hook.) Nutt.) site in western Montana and on a cedar (Thujaplicata (Donn ex D. Don) Lindl.)–hemlock (Tsugaheterophylla (Raf) Sarg.) site in northern Idaho. Nitrogen fixation in the forest floor, soil wood, and mineral soil on the subalpine fir site averaged 0.9 kg N•ha−1•year−1 in the uncut stand. This nitrogen input was reduced by 10% after clear-cutting followed by prescribed burning, and by 22% after clear-cutting followed by intensive residue removal. Nitrogen fixation in the uncut cedar–hemlock stand averaged 1.1 kg N•ha−1•year−1 and was reduced by 26% after prescribed burning. Clear-cutting only and clear-cutting followed by intensive woody residue removal had little effect on nitrogen fixation. However, large amounts of woody residue left on the cut site nearly doubled the amounts of nitrogen fixation compared with the uncut stand. Lower nitrogen fixation after harvesting on both the Idaho and Montana sites was due mostly to reductions in forest floor and large woody residue. Replacement of nitrogen losses from prescribed burning on these sites by nonsymbiotic nitrogen fixation and precipitation would take from 150 to 400 years, depending on the severity of the bum treatments.

scholarly journals Effects of Mineral Soil and Forest Floor on the Regeneration of Pedunculate Oak, Beech and Red Oak

Forests ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 66 ◽  
Author(s):  
Stefanie De Groote ◽  
Margot Vanhellemont ◽  
Lander Baeten ◽  
María Carón ◽  
An Martel ◽  
...  
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Red Oak ◽  
Pedunculate Oak

Nitrogen storage and availability during stand development in a New Zealand Nothofagus forest

2002 ◽  
Vol 32 (2) ◽  
pp. 344-352 ◽  
Author(s):  
P W Clinton ◽  
R B Allen ◽  
M R Davis
Keyword(s):  
New Zealand ◽  
Forest Floor ◽  
Woody Debris ◽  
Mineral Soil ◽  
Stand Development ◽  
N Availability ◽  
Net N Mineralization ◽  
Nitrogen Storage ◽  
Nothofagus Forest ◽  
Mature Stands

Stemwood production, N pools, and N availability were determined in even-aged (10, 25, 120, and >150-year-old) stands of a monospecific mountain beech (Nothofagus solandri var. cliffortioides (Hook. f.) Poole) forest in New Zealand recovering from catastrophic canopy disturbance brought about by windthrow. Nitrogen was redistributed among stemwood biomass, coarse woody debris (CWD), the forest floor, and mineral soil following disturbance. The quantity of N in stemwood biomass increased from less than 1 kg/ha in seedling stands (10 years old) to ca. 500 kg/ha in pole stands (120 years old), but decreased in mature stands (>150 years old). In contrast, the quantity of N stored in CWD declined rapidly with stand development. Although the mass of N stored in the forest floor was greatest in the pole stands and least in the mature stands, N availability in the forest floor did not vary greatly with stand development. The mass of N in the mineral soil (0–100 mm depth) was also similar for all stands. Foliar N concentrations, net N mineralization, and mineralizable N in the mineral soil (0–100 mm depth) showed similar patterns with stage of stand development, and indicated that N availability was greater in sapling (25 years old) and mature stands than in seedling and pole stands. We conclude that declining productivity in older stands is associated more with reductions in cation availability, especially calcium, than N availability.

scholarly journals Dynamic of nitrogen and dissolved organic carbon in an alpine forested catchment: atmospheric deposition and soil solution trends

2019 ◽  
Vol 34 ◽  
pp. 41-66 ◽  
Author(s):  
Raffaella Balestrini ◽  
Carlo Andrea Delconte ◽  
Andrea Buffagni ◽  
Alessio Fumagalli ◽  
Michele Freppaz ◽  
...  
Keyword(s):  
Soil Solution ◽  
Forest Ecosystem ◽  
Forest Floor ◽  
Mineral Soil ◽  
Chemical Species ◽  
Organic N ◽  
Seasonal Temperature ◽  
Inorganic N ◽  
Forest Floor Leachates ◽  
Throughfall Deposition

A number of studies have reported decreasing trends of acidifying and N deposition inputs to forest areas throughout Europe and the USA in recent decades. There is a need to assess the responses of the ecosystem to declining atmospheric pollution by monitoring the variations of chemical species in the various compartments of the forest ecosystem on a long temporal scale. In this study, we report on patterns and trends in throughfall deposition concentrations of inorganic N, dissolved organic N (DON) and C (DOC) over a 20-year (1995–2015) period in the LTER site -Val Masino (1190 m a.s.l.), a spruce forest, in the Central Italian Alps. The same chemical species were studied in the litter floor leachates and mineral soil solution, at three different depths (15, 40 and 70 cm), over a 10-year period (2005–2015). Inorganic N concentration was drastically reduced as throughfall and litter floor leachates percolated through the topsoil, where the measured mean values (2 µeq L-1) were much lower than the critical limits established for coniferous stands (14 µeq L-1). The seasonal temperature dependence of throughfall DOC and DON concentration suggests that the microbial community living on the needles was the main source of dissolved organic matter. Most of DOC and DON infiltrating from the litter floor were retained in the mineral soil. The rainfall amount was the only climatic factor exerting a control on DOC and N compounds in throughfall and forest floor leachates over a decadal period. Concentration of SO4 and NO3 declined by 50% and 26% respectively in throughfall deposition. Trends of NO3 and SO4 in forest floor leachates and mineral soil solution mirrored declining depositions. No trends in both DON and DOC concentration and in DOC/DON ratio in soil solutions were observed. These outcomes suggest that the declining NO3 and SO4 atmospheric inputs did not influence the dynamic of DON and DOC in the Val Masino forest. The results of this study are particularly relevant, as they are based on a comprehensive survey of all the main compartments of the forest ecosystem. Moreover, this kind of long-term research has rarely been carried out in the Alpine region.

scholarly journals Effects of land use change from natural forest to plantation on C, N and natural abundance of 13C and 15N along a climate gradient in eastern China

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mbezele Junior Yannick Ngaba ◽  
Ya-Lin Hu ◽  
Roland Bol ◽  
Xiang-Qing Ma ◽  
Shao-Fei Jin ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Forest Floor ◽  
Eastern China ◽  
Mineral Soil ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Natural Forests ◽  
Soil C ◽  
Mineral Soils

Abstract Soil C and N turnover rates and contents are strongly influenced by climates (e.g., mean annual temperature MAT, and mean annual precipitation MAP) as well as human activities. However, the effects of converting natural forests to intensively human-managed plantations on soil carbon (C), nitrogen (N) dynamics across various climatic zones are not well known. In this study, we evaluated C, N pool and natural abundances of δ13C and δ15N in forest floor layer and 1-meter depth mineral soils under natural forests (NF) and plantation forest (PF) at six sites in eastern China. Our results showed that forest floor had higher C contents and lower N contents in PF compared to NF, resulting in high forest floor C/N ratios and a decrease in the quality of organic materials in forest floor under plantations. In general, soil C, N contents and their isotope changed significantly in the forest floor and mineral soil after land use change (LUC). Soil δ13C was significantly enriched in forest floor after LUC while both δ13C and δ15N values were enriched in mineral soils. Linear and non-linear regressions were observed for MAP and MAT in soil C/N ratios and soil δ13C, in their changes with NF conversion to PF while soil δ15N values were positively correlated with MAT. Our findings implied that LUC alters soil C turnover and contents and MAP drive soil δ13C dynamic.

scholarly journals Free atmospheric CO<sub>2</sub> enrichment increased above ground biomass but did not affect symbiotic N<sub>2</sub>-fixation and soil carbon dynamics in a mixed deciduous stand in Wales

2011 ◽  
Vol 8 (2) ◽  
pp. 353-364 ◽  
Author(s):  
M. R. Hoosbeek ◽  
M. Lukac ◽  
E. Velthorst ◽  
A. R. Smith ◽  
D. L. Godbold
Keyword(s):  
Elevated Co2 ◽  
Forest Floor ◽  
Net Primary Production ◽  
Mineral Soil ◽  
Co2 Enrichment ◽  
Alnus Glutinosa ◽  
Plant Litter ◽  
Soil C ◽  
Face Experiment ◽  
Leaf N Content

Abstract. Through increases in net primary production (NPP), elevated CO2 is hypothesized to increase the amount of plant litter entering the soil. The fate of this extra carbon on the forest floor or in mineral soil is currently not clear. Moreover, increased rates of NPP can be maintained only if forests can escape nitrogen limitation. In a Free atmospheric CO2 Enrichment (FACE) experiment near Bangor, Wales, 4 ambient and 4 elevated [CO2] plots were planted with patches of Betula pendula, Alnus glutinosa and Fagus sylvatica on a former arable field. After 4 years, biomass averaged for the 3 species was 5497 (se 270) g m−2 in ambient and 6450 (se 130) g m−2 in elevated [CO2] plots, a significant increase of 17% (P = 0.018). During that time, only a shallow L forest floor litter layer had formed due to intensive bioturbation. Total soil C and N contents increased irrespective of treatment and species as a result of afforestation. We could not detect an additional C sink in the soil, nor were soil C stabilization processes affected by elevated [CO2]. We observed a decrease of leaf N content in Betula and Alnus under elevated [CO2], while the soil C/N ratio decreased regardless of CO2 treatment. The ratio of N taken up from the soil and by N2-fixation in Alnus was not affected by elevated [CO2]. We infer that increased nitrogen use efficiency is the mechanism by which increased NPP is sustained under elevated [CO2] at this site.

Nitrogen and phosphorus cycling following prescribed burning in natural and managed Aleppo pine forests

1999 ◽  
Vol 29 (8) ◽  
pp. 1237-1247 ◽  
Author(s):  
D Gillon ◽  
C Houssard ◽  
J C Valette ◽  
E Rigolot
Keyword(s):  
Forest Floor ◽  
Prescribed Burning ◽  
Pinus Halepensis ◽  
Fire Severity ◽  
Nutrient Balance ◽  
Pine Needles ◽  
Aleppo Pine ◽  
Slight Reduction ◽  
Nitrogen And Phosphorus ◽  
Natural Stand

Two prescribed burnings (downhill and uphill fires) were conducted in two stands of Aleppo pine (Pinus halepensis Mill.): a natural stand and a managed stand that was subject to thinning, pruning, and shrub removal. The concentrations of nitrogen (N) and phosphorus (P) in the pine needles and regrowth of the main shrub species, Quercus coccifera L., and the quantities of N and P in the needle fall and in the forest floor were measured during the 6 months following the fires. The concentrations of N and P in the pine needles and leaves of Q. coccifera increased compared with the unburned control after both fires in the natural stand, where there was only a slight reduction in fuel during prescribed burnings and where there was an abundant fall of scorched needles. In contrast, the chemical composition of the foliage was unchanged after the fires in the managed stand, where there was a greater reduction in fuel, and where only small quantities of scorched needles fell. This study showed that first opening prescribed burnings (natural stand) were less severe in terms of nutrient balance than maintenance prescribed burnings (managed stand) and that the forest floor reduction was a good indicator of fire severity.

The impact of root exclusion on duff moisture and fire danger

2015 ◽  
Vol 45 (8) ◽  
pp. 978-986 ◽  
Author(s):  
Dan K. Thompson ◽  
John Studens ◽  
Chelene Krezek-Hanes ◽  
B. Mike Wotton
Keyword(s):  
Water Content ◽  
Mineral Soil ◽  
Root Water Uptake ◽  
Volumetric Water Content ◽  
Exclusion Experiment ◽  
Stand Type ◽  
Low Levels ◽  
The Impact ◽  
Soil Interface ◽  
Root Exclusion

The impact of root water uptake on duff (both fibric and humic horizons) moisture was investigated at deciduous, mixedwood, and conifer stands in Ontario, Canada. Roots were actively excluded from the duff layer using geotextiles inserted at the duff–mineral soil interface and along the plot edges; liquid and vapour water flow was otherwise not affected by the geotextiles. Root exclusion caused little difference in duff moisture content prior to early June, after which the root exclusion plots remained at 15%–20% volumetric water content, whereas root-intact plots declined to as low as 5% volumetric water content during rain-free periods. Only in the root-intact plots did the duff water content reach sufficiently low levels that duff evaporation was limited by low water content. The net effect of root exclusion was to reduce the cumulative growing season water loss in the duff by 19%–31%, depending on the stand type. Root exclusion also decreased the number of days with a high probability of duff smouldering from as many as 72 days·year−1 to as few as 0 days·year−1. This root exclusion experiment provides a model for short-term duff moisture transitions under thinned forests such as those forests under community wildfire protection.

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