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 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.

Organic matter and nitrogen content of the forest floor in even-aged northern hardwoods

1984 ◽  
Vol 14 (6) ◽  
pp. 763-767 ◽  
Author(s):  
C. Anthony Federer
Keyword(s):  
Organic Matter ◽  
Nitrogen Content ◽  
Bulk Density ◽  
Forest Floor ◽  
Mineral Soil ◽  
Organic Content ◽  
Stand Age ◽  
Clear Cutting ◽  
Mature Forest ◽  
Forest Floors

Organic content of the forest floor decreases for several years after clear-cutting, and then slowly recovers. Thickness, bulk density, organic matter, and nitrogen content of forest floors were measured for 13 northern hardwood stands in the White Mountains of New Hampshire. Stands ranged from 1 to about 100 years in age. Forest-floor thickness varied significantly with stand age, but bulk density, organic fraction, and nitrogen fraction were independent of age. Total organic content of the forest floor agreed very well with data from Covington's (W. W. Covington 1981. Ecology, 62: 41–48) study of the same area. Both studies indicated that mature forest floors have about 80 Mg organic matter•ha−1 and 1.9 Mg nitrogen•ha−1. Within 10 or 15 years after cutting, the organic matter content of the floor decreases to 50 Mg•ha−1, and its nitrogen content to 1.1 Mg•ha−1. The question whether the decrease is rapid and the minimum broad and flat, or if the decrease is gradual and the minimum sharp, cannot be answered. The subsequent increase to levels reached in mature forest requires about 50 years. Some of the initial decrease in organic matter and nitrogen content of the forest floor may be caused by organic decomposition and nitrogen leaching, but mechanical and chemical mixing of floor into mineral soil, during and after the harvest operation, may also be important. The difference is vital with respect to maintenance of long-term productivity.

Effect of gap size on litter decomposition and soil nitrate concentrations in a high-elevation spruce–fir forest

2003 ◽  
Vol 33 (11) ◽  
pp. 2210-2220 ◽  
Author(s):  
Cindy E Prescott ◽  
Graeme D Hope ◽  
Leandra L Blevins
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
High Elevation ◽  
N Availability ◽  
Abies Lasiocarpa ◽  
Subalpine Fir ◽  
Engelmann Spruce ◽  
Nitrate Losses ◽  
Nitrate Concentrations ◽  
High Elevation Forest

Possible mitigation of nitrate losses associated with clearcuts through harvesting smaller gaps was tested in a high-elevation forest of Engelmann spruce (Picea engelmannii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.). We measured concentrations of ammonium and nitrate after 6-week buried bag incubations of forest floor and mineral soil samples in replicated plots of uncut forest and gaps of 10, 1.0, and 0.1 ha and single-tree removal for 7 years after harvest. Nitrate concentrations in forest floor and mineral soil were elevated 3–7 years after harvesting in gaps of 0.1 ha and larger. Removal of the same proportion of trees as single trees did not result in increased nitrate concentrations, suggesting that nitrate losses could be reduced by harvesting single trees rather than creating gaps. Greater N availability was not associated with faster rates of decomposition of litter and forest floor, which were similar in gaps of all sizes (0–10 ha). Reciprocal transplant of forest floor and soil from the 10-ha gaps and the uncut forests indicated that changes in the nature of the forest floor or soil following harvest had a greater influence on nitrate concentrations than the changes in environmental conditions in the gaps.

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.

Pathology of conifer seed and timing of germination in high-elevation subalpine fir and Engelmann spruce forests of the southern interior of British Columbia

1999 ◽  
Vol 29 (2) ◽  
pp. 187-193 ◽  
Author(s):  
Jianwen Zhong ◽  
Bart J van der Kamp
Keyword(s):  
British Columbia ◽  
Forest Floor ◽  
Mineral Soil ◽  
Seed Viability ◽  
Low Frequency ◽  
High Elevation ◽  
Subalpine Fir ◽  
Engelmann Spruce ◽  
Black Mold ◽  
Nurse Logs

Unstratified seed of Engelmann spruce (Picea engelmannii Parry) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) in nylon mesh bags was placed on various natural and disturbed forest floor seed beds in the Engelmann Spruce - Subalpine Fir Zone in the southern interior of British Columbia in September 1995 and recovered just before snow melt in June 1996. Fifty-two and 86% of the viable spruce and fir seed, respectively, had germinated before snowmelt. Germination under snow may be an adaptation of these high-elevation species to short cool growing seasons. Seed viability at recovery was significantly lower on undisturbed forest floor seed beds (spruce, 13%; fir, 12%) than on exposed mineral soil (spruce, 57%; fir, 42%). Viability of seed placed on nurse logs was 38 and 23% for spruce and fir, respectively. Isolation from ungerminated seed yielded a Rhizoctonia sp., an as yet unidentified black mold at high frequencies, and several other seed pathogens at low frequency. Multiple linear regression of the frequency of isolation of Rhizoctonia and black mold on seed viability was highly significant for both tree species. Seed pathogens appear to cause a major loss of seed and seedlings in these forests, and this may explain both the common occurrence of regeneration on nurse logs and the requirement of mineral soil seed beds for adequate regeneration.

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.

IN SITU NUTRIENT EXTRACTION BY RESIN FROM FORESTED, CLEAR-CUT AND SITE-PREPARED SOIL

1987 ◽  
Vol 67 (4) ◽  
pp. 943-952 ◽  
Author(s):  
H. H. KRAUSE ◽  
D. RAMLAL
Keyword(s):  
Forest Soil ◽  
Forest Floor ◽  
Mineral Soil ◽  
Ion Exchange Resin ◽  
Site Preparation ◽  
Tree Planting ◽  
Seasonal Effects ◽  
Soil Conditions ◽  
Clear Cut ◽  
Clear Cutting

Anion and cation resins were tested as sinks for nutrient ions under variable forest soil conditions. The resins, contained in nylon bags, were placed for periods of 4 wk below the forest floor of a softwood stand, and at approximately 7.5 cm depth on an adjacent clearcut with two different types of site preparation for tree planting. The soil was an Orthic Humo-ferric Podzol. Ion sorption below the forest floor, especially the sorption of ammonium, nitrate and phosphate, was strongly increased after clear-cutting of the forest. Sorption rates were generally lower in the mineral soil than immediately below the forest floor, except for nitrate and sulphate. Mixing of forest floor materials and fine logging debris into the mineral surface horizons generally increased resin sorption if compared to sorption in soil from which the forest floor had been removed. Resin sorption also revealed strong seasonal effects which may have been caused by changes in soil temperature and moisture. Key words: Ion exchange resin, forest soil fertility, seasonal nutrient fluctuation, site preparation

NOTES ON ZACOTUS MATTHEWSII LeC.

1944 ◽  
Vol 76 (9) ◽  
pp. 188-188 ◽  
Author(s):  
Melville H. Hatch ◽  
Kenneth M. Fender
Keyword(s):  
Pacific Northwest ◽  
Vancouver Island ◽  
Western Montana ◽  
The Pacific ◽  
Northern Idaho

Zacotus matthewsii LeC. (matthewsi auct.) is a rare beetle that lives in damp situations under cover in timbered areas in the Pacific Northwest. LeConte, Ann. Mag. Nat. Hist. (4) IV, 1869, p. 373-374, described it from a unique female from Vancouver Island. Horn, Trans. Ent. Soc. IX, 1881, p. 169, listed it from Washington; Leng, Cat. Col. Am. n. of Mex. 1920, p. 68, listed it from “No. Cal.”; Casey, Mem. Col. IX, 1920, p. 290-291, cited specimens from Moscow in northern Idaho and Clackamas Co. in northwestern Oregon; and Van Dyke, Pan-P. Ent. II, 1925, p. 95, from the Bitter Root Mountains of extreme western Montana.

The importance of forest floor disturbance in the early regeneration patterns of the boreal forest of western and central Quebec: a wildfire versus logging comparison

2000 ◽  
Vol 30 (9) ◽  
pp. 1353-1364 ◽  
Author(s):  
Thuy Nguyen-Xuan ◽  
Yves Bergeron ◽  
Dan Simard ◽  
Jim W Fyles ◽  
David Paré
Keyword(s):  
Forest Floor ◽  
Prescribed Burning ◽  
Sustainable Forest Management ◽  
Black Spruce ◽  
Vascular Plant ◽  
Correlation Coefficients ◽  
Detrended Correspondence Analysis ◽  
Clear Cut ◽  
Clear Cutting ◽  
Forest Floor Disturbance

The nonvascular and vascular plant composition of the early regenerating vegetation present following wildfires and clear-cut logging has been compared separately in three areas of the black spruce (Picea mariana (Mill.) BSP) - feathermoss (Pleurozium schreberi (Brid.) Mitt.)) forest of western and central Quebec. In each area, a detrended correspondence analysis successfully differentiated the burned and logged stands along the first ordination axis. This separation mainly resulted from the greater abundance of pioneer species or lichens after fire and the greater abundance of residual species after clear-cutting. Spearman's correlation coefficients were calculated to relate variables characterizing physical disturbance of the forest floor and general site conditions to the two first differentiating axes. Variables characterizing forest floor disturbance severity were strongly associated with the first ordination axis in two of the study areas but not in the third one. The interpretation of compositional differences in the light of plant reproductive strategies led to the identification of regeneration patterns that illustrated the influence of disturbance type and severity on post-disturbance vegetation composition. These results suggest that certain forestry practices such as careful logging with the protection of regeneration and soil, scarification, and prescribed burning may differ in their capability to address sustainable forest management issues.

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