Nitrate formation and movement before and after clear-cutting of a monitored watershed in central New Brunswick, Canada

1982 ◽  
Vol 12 (4) ◽  
pp. 922-930 ◽  
Author(s):  
H. H. Krause

A watershed of 391 ha, supporting tolerant hardwoods on elevated sloping portions and softwoods on low lying areas, was clear-cut in 1978. Nitrate nitrogen was monitored over 5 years before and 3 years after clear-cutting by periodic extraction of soil solution samples and continuous sampling of the brooks draining the cut and a similar control watershed. The brooks were gauged to determine water discharge. Before clear-cutting, nitrate nitrogen was not detectable for most of the time in soil solutions under softwood cover, but occurred commonly under hardwood cover with concentrations ranging upward to 4.7 mg/L. Nitrate nitrogen in the brooks varied from undetectable to 0.3 mg/L. After clear-cutting, nitrate nitrogen increased to maximum concentrations of 13.4 mg/L, in the soil solution under hardwood cover, and 1.6 mg/L, in the main channel of the brook. Soil solution nitrogen was not changed significantly by clear-cutting of softwood stands. The 3-year cumulative nitrogen loss attributable to clear-cutting was 19.1 kg/ha. Nitrate nitrogen in soil solutions, branch, and main stream indicated that disproportionately larger amounts of nitrogen were lost from the elevated and sloping portions of the watershed than from the lower lying areas.

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Siti Aisah Shamsuddin ◽  
Zulkifli Yusop ◽  
Shoji Noguchi

A study was conducted on the impact of forest clearance on discharge from newly established Hopea odorata plantations catchment (14.4 ha). The stands were two years old when this study commenced in year 2006 and the data collection was carried out for two years. The forested catchment (C3) was clear-cut during the preparation of the forest plantation and catchment C1 was left undisturbed. Discharge and rainfall were measured continuously for two years. The discharge measured from years 1997 to 2003 was used also to determine the water yield before and after forest clear-cut. This study showed that the plantation catchment is more responsive to storm with higher total water yield than in the forested catchment. The effect of forest clear cutting to discharge was clearly shown by the increment in the amount following the clear-cut activities and time taken for the recovery of the discharge back to its original state was almost three years. The peak discharge in C3 also was affected in which the biggest change was obtained during the forest clear-cutting period compared with during calibration and after clearing periods. This study is useful as basis for improving the existing guidelines on forest plantation establishment.


2005 ◽  
Vol 9 (6) ◽  
pp. 657-674 ◽  
Author(s):  
A. Laurén ◽  
L. Finér ◽  
H. Koivusalo ◽  
T. Kokkonen ◽  
T. Karvonen ◽  
...  

Abstract. A two dimensional model, FEMMA, to describe water and nitrogen (N) fluxes within and from a forested first-order catchment (Kangasvaara in Eastern Finland) was constructed by linking the most significant processes affecting the fluxes of water, ammonium, nitrate and dissolved organic nitrogen along a hillslope from the water divide to the stream. The hillslope represents the average flowpath of water in the catchment and the model was used to estimate the N fluxes for a catchment in eastern Finland before and after clear-cutting. The simulated results were in reasonable agreement with the nitrate, dissolved organic N and dissolved total N measurements from the study catchment and with other results in the literature. According to the simulations, the major sinks of N after clear-cutting were immobilisation by soil microbes, uptake by ground vegetation and sorption to soil. These sinks increased downslope from the clear-cut area, indicating the importance of an uncut buffer zone between the stream and the clear-cut area in reducing N exports. The buffer zone retained 76% of the N flux coming from the clear-cut area. Nitrification was a key process in controlling the N export after clear-cutting and N increases were mainly as nitrate. Most of the annual N export took place during the spring flood, when uptake of N by plants was minimal.


1995 ◽  
Vol 75 (4) ◽  
pp. 475-490 ◽  
Author(s):  
Kevin Jewett ◽  
David Daugharty ◽  
Helmut H. Krause ◽  
Paul A. Arp

Elemental concentrations (H, Ca, Mg, K, Na, NH4-N, NO3-N, P) and water flux data for precipitation and stream discharge as well as ion concentration data for soil solutions were collected and summarized for the Hayden Brook (HB) and Narrows Mountain Brook (NMB) watersheds of the Nashwaak Experimental Watershed Project (NEWP) in Central New Brunswick. Elemental concentrations, fluxes and stream discharge from both watersheds were compared for pre- and post-harvest periods (1972–1978 and 1978–1984, respectively). For soil and streamwater solutions, elemental concentrations were typically highest in late summer to fall, and continued to be high throughout the dormant season. For the soil solution, concentrations of NO3-N, NH4-N, Ca and K peaked in midsummer. Highest NO3-N concentrations were found in post-harvest soil solutions taken from hardwood sites. Nitrate levels were low in soil solutions taken from conifer sites, with post-harvest levels slightly higher than pre-harvest levels. Soil solution concentrations were found to vary with soil depth: pH values were lowest at the surface, and increased uniformly with depth; bases (Ca, Mg, K, Na) and NO3-N tended to be lowest at intermediate soil depth. Seasonally divergent trends were observed for post-harvest NO3-N in soil solutions and in streamwater: midsummer levels were high in the former, but low for the latter. Several aspects likely contributed to this divergence: (1) enhanced rates of N mineralization and nitrification in upland soils during post-harvest midsummers, (2) reduced post-harvest vegetational N uptake, (3) possibly accelerated N absorption by microbes and vegetation in the wet areas of the cut watershed. Altogether, post-harvest effects on stream discharge and streamwater chemistry were short-term: differences for elemental concentrations and stream discharge became insignificant after about 5 and 10–12 yr, respectively. Vegetation, especially tolerant hardwoods, recovered rapidly from stump and root sprouts. Key words: Clearcutting, stream discharge, soil solution, pH, Ca, Mg, K, Na, P, NO3-N, NH4-N, seasonal trends


1983 ◽  
Vol 61 (5) ◽  
pp. 970-980 ◽  
Author(s):  
Arthur M. Martell

Changes in small mammal communities following logging were monitored in clear-cut and strip-cut upland black spruce (Picea mariana) stands and in selectively cut mixed wood stands in north-central Ontario. Clear-cutting and subsequent scarification essentially eliminated the vegetative cover. Much of the ground cover recovered within 5 years and shrubs within 12 years, but mosses and lichens took much longer. The small mammal community in both clear-cut and strip-cut stands changed over the first three years after logging from one dominated by southern red-backed voles (Clethrionomys gapperi) to one dominated by deer mice (Peromyscus maniculatus) and then remained relatively stable for up to 13 years after harvest. That shift was not apparent in selectively cut mixed wood stands where the composition of the small mammal community was similar between uncut stands and stands 4–23 years after harvest. There was relatively little change in total numbers of small mammals after logging. In general, the diversity and evenness of small mammals increased or remained stable in the first 1–3 years following harvest, decreased on older (3–16 years) cuts, and then increased to values similar to those in uncut stands on the oldest (19–23 years) cuts.


Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1542
Author(s):  
Nadezhda V. Genikova ◽  
Viktor N. Mamontov ◽  
Alexander M. Kryshen ◽  
Vladimir A. Kharitonov ◽  
Sergey A. Moshnikov ◽  
...  

Bilberry spruce forests are the most widespread forest type in the European boreal zone. Limiting the clear-cuttings size leads to fragmentation of forest cover and the appearance of large areas of ecotone complexes, composed of forest (F), a transition from forest to the cut-over site under tree canopy (FE), a transition from forest to the cut-over site beyond tree canopy (CE), and the actual clear-cut site (C). Natural regeneration of woody species (spruce, birch, rowan) in the bilberry spruce stand—clear-cut ecotone complex was studied during the first decade after logging. The effects produced by the time since cutting, forest edge aspect, and the ground cover on the emergence and growth of trees and shrubs under forest canopy and openly in the clear-cut were investigated. Estimating the amount and size of different species in the regeneration showed FE and CE width to be 8 m—roughly half the height of first-story trees. Typical forest conditions (F) feature a relatively small amount of regenerating spruce and birch. The most favorable conditions for natural regeneration of spruce in the clear-cut—mature bilberry spruce stand ecotone are at the forest edge in areas of transition both towards the forest and towards the clear-cut (FE and CE). Clear-cut areas farther from the forest edge (C) offer an advantage to regenerating birch, which grows densely and actively in this area.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Mustakim Mustakim ◽  
Indarto Indarto ◽  
Purnomo Purnomo

This research aims to reduce the effect of pressure fluctuations intensity on the sudden expansion of two phase flow of air - water in the same direction with the horizontal placement of the ring. Measurements done by installing a differential pressure transducer device that is placed on pressure points before and after sudden expansion. Output voltage signal recorded by a digital storage osciloscope. Tests conducted on water discharge 0.000038 m 3 / s; 0.000078 m 3 / s; 0.000116 m 3 / s; 0.000154 m 3 / s; 0.000198 m 3 / s; 0.000244 m 3 / s; 0.000284 m 3 / s and air flow 0.000065 m 3 / s; 0.00013 m 3 / s; 0.000195 m 3 / s; 0.000255 m 3 / s; 0.00032 m 3 / s; 0.000385 m 3 / s; 0.00045 m 3 / s. Results showed that if the total mass flow rate increases the pressure drop increases. Installation of the ring can reduce the pressure fluctuations intensity, the most effective installation of the ring using the ring the same diameter. Flow path is generally slug and plug flow pattern.


2020 ◽  
Vol 50 (7) ◽  
pp. 608-614
Author(s):  
Ronei Baldissera ◽  
Suiane Oliveira de Quadros ◽  
Gabriela Galeti ◽  
Everton Nei Lopes Rodrigues ◽  
Luan M.V. Lazzarotto ◽  
...  

Habitat loss is one of the main consequences of landscape transformation by humans. Monitoring biodiversity changes in areas under different management strategies is fundamental for species conservation. Our study is the first to assess the role of forest disturbance history on spider (Araneae) biodiversity in the westernmost portion of the Atlantic Forest. We analyzed taxonomic and functional aspects of spider assemblages in understories in a large forest fragment in southwestern Brazil. Spiders were sampled in five 30 m × 5 m plots over three seasons in three areas with different management histories: clear-cutting, selective logging, or native plots. We also characterized tree basal area, tree density, and canopy openness. The clear-cut plots showed more canopy openness and low habitat heterogeneity due to the high density of one pioneer native tree species. Forest structure in selective logging and native plots was similar. Spider richness, abundance, and functional richness were affected only by the season. Species composition also differed among the areas depending on the season. The abundance of web-building species was mainly associated with clear-cut areas in winter and spring. These results highlight the importance of natural regeneration in the Atlantic Forest after disturbance for the conservation of regional spider biodiversity.


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