Clearcut harvesting effects on soil and creek inorganic nitrogen in high elevation forests of southern interior British Columbia

2009 ◽  
Vol 89 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Graeme D Hope

Responses of both soil and stream inorganic nitrogen (N) after operational clearcut harvesting were explored in two high elevation British Columbia Engelmann spruce-Subalpine fir (ESSF) forests. At one study site, net N mineralization was measured between 1 and 11 yr after harvest. At a second site, for 3 yr after harvesting, available soil ammonium and nitrate were measured using ion exchange resins, and drainage losses of N were estimated using tension lysimeters and soil water balance models. Stream water N concentrations were also measured in one unlogged, and two logged watersheds at the second study area for 12 yr, both pre- and post-clearcut harvesting. Growing season as well as over-winter increases in post-harvest soil nitrate were detected after 3 yr, and the increases were apparent for up to 11 yr. Seasonal losses of N in drainage were greater in clearcut soils than in the forest soils in year 2 for ammonium and in years 2 and 3 for nitrate. A high proportion of the N was lost in drainage during snowmelt. Stream water ammonium in all three streams and nitrate in the unlogged and one harvested creek remained at or below the detection level. In the third creek, the frequency of detection and concentrations of nitrate peaked 2 to 3 yr after 30 to 57% of the watershed was harvested. The annual peak in NO3-N concentrations occurred immediately before the snowmelt-driven stream flow peak. Drainage losses and stream N fluxes were both small, relative to the total soil N content. Key words: Nitrogen, N mineralization, nitrate, harvesting, leaching, stream N, snowmelt

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.


Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 444 ◽  
Author(s):  
Chen-Chi Tsai ◽  
Yu-Fang Chang

Adding biochar to excessive compost amendments may affect compost mineralization rate and nitrogen (N) availability. The objective of this 371-day incubation study was to evaluate the effects of four proportions of woody biochar (0%, 0.5%, 1.0%, and 2.0%) from lead tree (Leucaena leucocephala (Lam.) de. Wit) biochar produced at 750 °C through dynamic mineral N and N mineralization rates in three rural soils (one Oxisol and two Inceptisols). In each treatment, 5% poultry–livestock manure compost was added to serve as an excessive application. The results indicated that the biochar decreased available total inorganic nitrogen (TIN) (NO3−-N+NH4+-N) by on average 6%, 9% and 19% for 0.5%, 1.0% and 2.0% treatments, respectively. The soil type strongly influenced the impact of the biochar addition on the soil nitrogen mineralization potential, especially the soil pH and clay content. This study showed that the co-application of biochar and excessive compost benefited the agricultural soils by improving NO3−-N retention in agroecosystems. The application of biochar to these soils to combine it with excessive compost appeared to be an effective method of utilizing these soil amendments, as it diminished the net N mineralization potential and reduced the nitrate loss of the excessive added compost.


1994 ◽  
Vol 24 (8) ◽  
pp. 1636-1645 ◽  
Author(s):  
Charles T. Garten Jr. ◽  
Helga Van Miegroet

We tested the hypothesis that naturally occurring nitrogen (N) isotope ratios in foliage (from plants that do not symbiotically fix atmospheric N2) are an indicator of soil N dynamics in forests. Replicate plots were established at eight locations ranging in elevation from 615 to 1670 m in Great Smoky Mountains National Park in eastern Tennessee, U.S.A. The locations selected ranged from N-poor (low-elevation) to N-rich (high-elevation) forest stands. Soils were sampled in June 1992; plants, forest floors, and upper mineral soils were sampled in August 1992. Net N mineralization and net nitrification potentials for surface mineral soils and organic matter layers at each site were determined by aerobic laboratory incubations. Soils and organic layers from high-elevation sites had greater net N mineralization and nitrification potentials than soils from low-elevation sites. There were significant (P ≤ 0.05) differences between study sites in soil 15N abundance. Therefore, we examined correlations between measures of soil N availability and both mean foliar δ15N values and mean enrichment factors (εp−s = δ15Nleaf − δ15Nsoil). In evergreens, maples, and ferns, mean foliar δ15N values and mean enrichment factors were positively correlated with net N mineralization and net nitrification potentials in soil. The observed relationships between natural 15N abundance in plant leaves and soil N availability were explained by a simple model of soil N dynamics. The model predicts how the isotopic composition of plant N is affected by the following factors: (i) varying uptake of soil NH4-N and NO3-N, (ii) the isotopic composition of different soil N pools, and (iii) relative rates of soil N transformations.


2004 ◽  
Vol 34 (5) ◽  
pp. 1018-1024 ◽  
Author(s):  
Todd E Redding ◽  
Graeme D Hope ◽  
Margaret G Schmidt ◽  
Marie-Josée Fortin

Edge effects are becoming an important forest management consideration, but information regarding the influence of edges on N cycling variables has not been well documented. In addition, the quantification of edge effects can benefit from the application of complementary spatial analysis methods. Forest floor N mineralization and environmental variables were intensively measured 5 years after harvest along transects crossing the north and south edges of a 1-ha clearcut, in a high-elevation Engelmann spruce – subalpine fir forest. Wavelet analysis and depth-of-edge influence (DEI) methods were used to locate and measure the spatial extent of edge effects on N mineralization. Then variance partitioning (partial redundancy analysis) was used to examine the influence of edges on N mineralization relative to the influence of other environmental factors. Initial NO3-N content and net nitrification markedly increased in the opening within 2–6 m of each edge. Net ammonification did not exhibit obvious edge-related spatial patterns. Spatial patterns of nitrification appeared to be more closely related to spatial changes in substrate quality than to soil temperature and moisture. Results of the wavelet and DEI analyses provided quantification of locations and functional extents of edge effects.


2004 ◽  
Vol 35 (4-5) ◽  
pp. 347-357 ◽  
Author(s):  
K. Rankinen ◽  
K. Granlund ◽  
I. Bärlund

Concentrations of inorganic nitrogen (N) in non-polluted and undisturbed northern rivers are often lower during summer than during the dormant season. The great difference between summer and winter N concentrations probably reflects higher soil water N contents in the dormant season compared with the growing season, when inorganic N is usually retained effectively. Microbial activity in soil is observed even in sub-zero temperatures and it is generally assumed that in the northern latitudes some N mineralization occurs during winter. The dynamic, semi-distributed INCA (Integrated Nitrogen in Catchments) model was applied to the Simojoki river basin in the boreal zone in northern Finland. With this model process rates and loads of N can be simulated in different land use modes. The INCA model was not able to simulate the high inorganic N concentrations in the river water in winter unless N processes in sub-zero temperatures were included. The aim of this study was to compare the simulated N mineralization in two different land use modes: boreal forests on mineral soil and agricultural fields. Net N mineralization occurring during the season when soil is mainly frozen (November–April) accounted for 43% of the annual N mineralization. This work indicates the importance of over-winter N processes in northern areas, which should be taken into account when modelling nutrient leaching.


2005 ◽  
Vol 35 (8) ◽  
pp. 1877-1888 ◽  
Author(s):  
Roberta Parish ◽  
Joseph A Antos

We examined the potential of natural regeneration for stocking 1-ha patch cuts in high-elevation Engelmann spruce (Picea engelmannii Parry) – subalpine fir (Abies lasiocarpa (Hook.) Nutt.) forests. Using the Sicamous Creek Silvicultural Systems site, which was harvested during winter 1994–1995, we established 1-m2 plots in patch cuts, forest edge, and untreated control forest. We marked and recorded microsite characteristics for all advanced regeneration and new recruits for up to 5 years; over 12 000 individuals were included. Advanced regeneration was abundant and was about one-quarter spruce. Spruce and fir germinants occurred in all years, but numbers varied greatly, with a very large cohort in 1998. Both advanced regeneration and new recruits were concentrated on decaying logs. Mortality of advanced regeneration was high in the patch cuts following harvest, but subsequent survival was good, approaching rates in the untreated forest within 4 years. Survival rates were higher for spruce than fir, but differed little among surface types and microtopographic positions. Survival of new recruits was high, approximately 50% the first year and 70% during the second, and was similar between spruce and fir. If the 1998 cohort has similar survival, the patch cuts could be adequately stocked. Use of natural regeneration, in combination with infill planting, is a viable option for stocking small openings in wet high-elevation forests in southern British Columbia.


2000 ◽  
Vol 80 (3) ◽  
pp. 401-410 ◽  
Author(s):  
T. A. Forge ◽  
S. W. Simard

The trophic structure of nematode communities, lengths of fungal hyphae, and gross populations of protozoa and bacteria were compared between clearcuts and adjacent forests at three sites in the southern interior of British Columbia in 1996, 1997, and 1998. Total C and N, mineralizable N (anaerobic incubation), and N mineralised during aerobic incubations, were determined from the same soil samples used for biological assays. Net N mineralization did not differ between clearcuts and forests in 1997; in 1998 net N mineralization in the organic horizon was four times greater for forests than for clearcuts. Hyphal lengths and total microbial biomass were greater in forest soil than in clearcut soil. Bacterial abundance was greater in forest soil than in clearcut soil in 1996 only. The abundance of protozoa did not differ between clearcuts and forests. Fungivorous, omnivorous, and predacious nematodes were less abundant in clearcut soil than in forest soil. Bacterivorous nematodes were more abundant in the mineral soil of clearcuts than in forests in 1996, but did not differ between clearcuts and forests in any other combination of year and horizon. Net N mineralization was correlated with the ratio of bacterial biomass/fungal biomass (r = 0.72, 12 degrees of freedom), as well as the abundance of amoebae (r = 0.83), total nematodes (r = 0.80), bacterivorous nematodes (r = 0.74), and fungivorous nematodes (r = 0.83). Key words: Microfauna, nematode ecology, microbial biomass, clearcut harvesting, nitrogen mineralization


1999 ◽  
Vol 29 (2) ◽  
pp. 187-193 ◽  
Author(s):  
Jianwen Zhong ◽  
Bart J van der Kamp

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.


Rangifer ◽  
2007 ◽  
Vol 27 (4) ◽  
pp. 141 ◽  
Author(s):  
Michaela J. Waterhouse ◽  
Harold M. Armleder ◽  
Amanda F. Linnell Nemec

Group selection silvicultural systems have been recommended for managing mountain caribou (Rangifer tarandus caribou) habitat in high elevation Engelmann spruce – subalpine fir forests in east-central British Columbia. We measured the response of arboreal lichen (a key winter forage) to harvesting of 30% of the forested area using three partial cutting treatments, which created small (0.03 ha), medium (0.13 ha), and large (1.0 ha) openings, and a no-harvest treatment. Treatments were replicated on four sites, and monitored over a ten year post-harvest period. The short-term loss of lichen associated with removal of approximately one third of the trees was partially offset by a significant (P=0.01) increase in lichen abundance on trees in the caribou feeding zone (up to 4.5 m) in the three partial cutting treatments relative to trees in the uncut forest. Differences among treatments in the change in lichen composition, as measured by the percentage of Alectoria sarmentosa and Bryoria spp., were marginally significant (P=0.10). The partial cutting treatments showing a greater likelihood of shifting towards more Bryoria spp. than no-harvest treatment (P=0.04). In the year of harvest (1993), larger trees were found to hold more lichen than smaller trees (P=0.04), and live trees supported more lichen than dead trees (P=0.01), but lichen loading was similar among tree species (P=0.51). Tree fall rates were similar among treatments, based on the ten year average (0.6–0.8% of sample trees per year). The results indicate that caribou foraging habitat is maintained in the residual forest when group selection systems that remove only 30% of the trees are applied. Information on the distribution of lichen is useful for developing stand level prescriptions. Providing lichen bearing habitat meets just one of the needs of caribou. A comprehensive approach that considers all factors and their interactions is essential to maintain and recover the threatened mountain caribou.


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