Stream temperature responses to partial-harvest logging in riparian buffers of boreal mixedwood forest watersheds

2009 ◽  
Vol 39 (3) ◽  
pp. 497-506 ◽  
Author(s):  
David P. Kreutzweiser ◽  
Scott S. Capell ◽  
Stephen B. Holmes

As part of a larger study to examine the operational feasibility, ecological benefits, and environmental impacts of partial-harvest logging in riparian buffers along boreal mixedwood forest streams, we determined the effects on summer stream temperatures. Three logged study reaches were compared with three reference reaches over two prelogging and two postlogging summers. Partial-harvest logging resulted in an average removal of 10%, 20%, and 28% of the basal area from riparian buffers at the three logged sites. At the two more intensively logged sites, there were small (<10%) reductions in canopy cover (P = 0.024) and no significant changes in light at stream surfaces (P > 0.18). There were no measurable impacts on stream temperatures at two of the three logged sites. At the most intensively logged site, daily maximum temperatures were significantly higher (∼4 °C) for about 6 weeks in the first summer after logging than in prelogging years or at the reference sites (P < 0.001). Temperature increases were attributed to a logging-induced temporary disruption of cool water inputs from ground disturbance in a lateral-input seep area. Our results indicate that partial-harvest logging in riparian buffers of boreal mixedwood forest streams can sustain effective canopy cover and mitigate logging-induced water temperature increases.

2013 ◽  
Vol 43 (11) ◽  
pp. 993-1005 ◽  
Author(s):  
Elizabeth Cole ◽  
Michael Newton

Determining the effectiveness of different riparian buffers for mitigating forest-harvesting impacts on stream temperatures continues to be of interest throughout the world. Four small, low or medium elevation streams in managed western Oregon forests were studied to determine how the arrangement and amount of streamside retention strips (buffers) in clear-cut units influenced stream temperatures. Buffers included (i) no tree, (ii) predominantly sun-sided 12 m wide partial, and (iii) two-sided (Best Management Practice, (BMP)) 15–30 m wide buffers. Harvested units alternated with uncut units along 1800–2600 m study reaches. Impacts of harvesting on stream temperatures were determined by time series comparisons of postharvest and preharvest regressions. Trends for daily maximum and mean stream temperature significantly increased after harvest in no tree buffer units. Partial buffers led to slight (<2 °C) or no increased warming. BMP units led to significantly increased warming, slight, or no increased warming. Temperature responses in uncut units appeared to be linked to responses in upstream harvested units. In many instances, when harvested units exhibited significantly higher postharvest trends, lower trends were observed in the uncut units downstream. Stream temperature trends of 7 day moving maxima indicated warming through the no tree buffer units and some of the BMP units. Peaks in maxima were not maintained in downstream units. Stream temperature responses were related to buffer implementation and stream features, relating to cooling and warming.


2002 ◽  
Vol 59 (12) ◽  
pp. 1886-1900 ◽  
Author(s):  
Eric Mellina ◽  
R Dan Moore ◽  
Scott G Hinch ◽  
J Stevenson Macdonald ◽  
Greg Pearson

Although the future timber supply in the northern hemisphere is expected to come from boreal and subboreal forests, little research has been conducted in these regions that examines the temperature responses of small, lake-headed streams to streamside timber harvesting. We examined the temperature patterns of two subboreal outlet streams in north-central British Columbia for 1 year before and 3 years after clearcut logging and found only modest changes (averaging 0.05–1.1°C) with respect to summer daily maximum and minimum temperatures, diurnal fluctuations, and stream cooling. A multistream comparative survey conducted in the same geographic region revealed that streams headed by small lakes or swamps tended to cool as they flowed downstream, and headwater streams warmed, regardless of whether or not timber harvesting took place. Stream cooling was attributed to a combination of warm outlet temperatures (promoted by the presence of the lakes) and cold groundwater inflows. A regression model revealed that summertime downstream warming or cooling in headwater and outlet streams could be predicted by upstream maximum summer temperatures and canopy cover. Lentic water bodies and groundwater inflows are important determinants of stream temperature patterns in subboreal forests and may subsequently moderate their responses to streamside harvesting.


2004 ◽  
Vol 21 (1) ◽  
pp. 19-30 ◽  
Author(s):  
David P. Kreutzweiser ◽  
Scott S. Capell ◽  
Frederick D. Beall

Abstract Organic matter inputs and accumulation were measured in streams of low-order forest watersheds across a gradient of selective harvesting with no protective riparian buffers assigned. Comparisons were made among sites in selection-cut (average 29% basal area removal), shelterwood-cut (average 42% basal area removal), diameter limit-cut (average 89% basal area removal), and undisturbed tolerant hardwood catchments. The diameter limit harvest was an intentionally high-disturbance treatment and is not a normal silvicultural prescription for tolerant hardwoods in Ontario. Time trend analyses were conducted to examine differences among sites over a pre- and postharvest experimental period. Selection-based harvesting at up to 42% basal area removal with no riparian buffers did not significantly alter average over-stream canopy cover, leaf litter and other organic matter inputs, benthic particulate organic matter accumulation, or woody debris abundance. Harvesting impacts on over-stream canopy cover and organic matter inputs appeared to be minimized by natural crown architecture (overlap in crowns of over-stream trees, residual mid-crown canopy) and by careful logging practices including retention of many immediate streamside trees (within a few meters of the stream channel) and avoidance of felling directly into the streams. Dissolved organic matter fluxes increased slightly for 1 year after harvest and were associated with increased water yield. At the diameter limit harvesting intensity (about 89% basal area removal), significant effects on organic matter inputs and accumulation in streams were detected. The results indicate that selective harvesting of hardwood forests at up to about 42% basal area removal can be conducted without causing significant reductions in organic matter inputs and accumulation in headwater streams, even without prescribed streamside buffer strips.


2021 ◽  
Vol 13 (12) ◽  
pp. 2297
Author(s):  
Jonathon J. Donager ◽  
Andrew J. Sánchez Meador ◽  
Ryan C. Blackburn

Applications of lidar in ecosystem conservation and management continue to expand as technology has rapidly evolved. An accounting of relative accuracy and errors among lidar platforms within a range of forest types and structural configurations was needed. Within a ponderosa pine forest in northern Arizona, we compare vegetation attributes at the tree-, plot-, and stand-scales derived from three lidar platforms: fixed-wing airborne (ALS), fixed-location terrestrial (TLS), and hand-held mobile laser scanning (MLS). We present a methodology to segment individual trees from TLS and MLS datasets, incorporating eigen-value and density metrics to locate trees, then assigning point returns to trees using a graph-theory shortest-path approach. Overall, we found MLS consistently provided more accurate structural metrics at the tree- (e.g., mean absolute error for DBH in cm was 4.8, 5.0, and 9.1 for MLS, TLS and ALS, respectively) and plot-scale (e.g., R2 for field observed and lidar-derived basal area, m2 ha−1, was 0.986, 0.974, and 0.851 for MLS, TLS, and ALS, respectively) as compared to ALS and TLS. While TLS data produced estimates similar to MLS, attributes derived from TLS often underpredicted structural values due to occlusion. Additionally, ALS data provided accurate estimates of tree height for larger trees, yet consistently missed and underpredicted small trees (≤35 cm). MLS produced accurate estimates of canopy cover and landscape metrics up to 50 m from plot center. TLS tended to underpredict both canopy cover and patch metrics with constant bias due to occlusion. Taking full advantage of minimal occlusion effects, MLS data consistently provided the best individual tree and plot-based metrics, with ALS providing the best estimates for volume, biomass, and canopy cover. Overall, we found MLS data logistically simple, quickly acquirable, and accurate for small area inventories, assessments, and monitoring activities. We suggest further work exploring the active use of MLS for forest monitoring and inventory.


2015 ◽  
Vol 54 (3) ◽  
pp. 658-670 ◽  
Author(s):  
Jenny Lindén ◽  
Jan Esper ◽  
Björn Holmer

AbstractUrban areas are believed to affect temperature readings, thereby biasing the estimation of twentieth-century warming at regional to global scales. The precise effect of changes in the surroundings of meteorological stations, particularly gradual changes due to urban growth, is difficult to determine. In this paper, data from 10 temperature stations within 15 km of the city of Mainz (Germany) over a period of 842 days are examined to assess the connection between temperature and the properties of the station surroundings, considering (i) built/paved area surface coverage, (ii) population, and (iii) night light intensity. These properties were examined in circles with increasing radii from the stations to identify the most influential source areas. Daily maximum temperatures Tmax, as well as daily average temperatures, are shown to be significantly influenced by elevation and were adjusted before the analysis of anthropogenic surroundings, whereas daily minimum temperatures Tmin were not. Significant correlations (p < 0.1) between temperature and all examined properties of station surroundings up to 1000 m are found, but the effects are diminished at larger distance. Other factors, such as slope and topographic position (e.g., hollows), were important, especially to Tmin. Therefore, properties of station surroundings up to 1000 m from the stations are most suitable for the assessment of potential urban influence on Tmax and Tmin in the temperate zone of central Europe.


2008 ◽  
Vol 16 (NA) ◽  
pp. 157-179 ◽  
Author(s):  
David P. Kreutzweiser ◽  
Paul W. Hazlett ◽  
John M. Gunn

Logging disturbances in boreal forest watersheds can alter biogeochemical processes in soils by changing forest composition, plant uptake rates, soil conditions, moisture and temperature regimes, soil microbial activity, and water fluxes. In general, these changes have often led to short-term increases in soil nutrient availability followed by increased mobility and losses by leaching to receiving waters. Among the studies we reviewed, dissolved organic carbon (DOC) exports usually increased after logging, and nitrogen (N) mineralization and nitrification often increased with resulting increased N availability and exports to receiving waters. Similar processes and responses occurred for phosphorus (P), but to a lesser extent than for N. In most cases, base cations were released and exported to receiving waters after logging. Several studies demonstrated that stem-only or partial-harvest logging reduced the impacts on nutrient release and exports in comparison to whole-tree clear-cutting. Despite these logging-induced increases in soil nutrient availability and movement to receiving waters, most studies reported little or no change in soil chemical properties. However, responses to logging were highly variable and often site specific. The likelihood, extent and magnitude of logging impacts on soil nutrient cycling and exports in boreal forest watersheds will be dependent on soil types, stand and site conditions, hydrological connectivity, post-logging weather patterns, and type and timing of harvest activities. Additionally, logging impacts can interact with, and be confounded by, atmospheric pollutant deposition and climate change. Further watershed-level empirical studies and modeling efforts are required to elucidate these interactions, to improve predictive capabilities, and to advance forest management guidelines for sustaining forest soil productivity and limiting nutrient exports.


Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1584
Author(s):  
Ivana Tošić ◽  
Suzana Putniković ◽  
Milica Tošić ◽  
Irida Lazić

In this study, extremely warm and cold temperature events were examined based on daily maximum (Tx) and minimum (Tn) temperatures observed at 11 stations in Serbia during the period 1949–2018. Summer days (SU), warm days (Tx90), and heat waves (HWs) were calculated based on daily maximum temperatures, while frost days (FD) and cold nights (Tn10) were derived from daily minimum temperatures. Absolute maximum and minimum temperatures in Serbia rose but were statistically significant only for Tx in winter. Positive trends of summer and warm days, and negative trends of frost days and cold nights were found. A high number of warm events (SU, Tx90, and HWs) were recorded over the last 20 years. Multiple linear regression (MLR) models were applied to find the relationship between extreme temperature events and atmospheric circulation. Typical atmospheric circulation patterns, previously determined for Serbia, were used as predictor variables. It was found that MLR models gave the best results for Tx90, FD, and Tn10 in winter.


2019 ◽  
Vol 23 (11) ◽  
pp. 4491-4508 ◽  
Author(s):  
John R. Yearsley ◽  
Ning Sun ◽  
Marisa Baptiste ◽  
Bart Nijssen

Abstract. Aquatic ecosystems can be significantly altered by the construction of dams and modification of riparian buffers, and the effects are often reflected in spatial and temporal changes to water temperature. To investigate the implications for water temperature of spatially and temporally varying riparian buffers and dam-induced hydrologic alterations, we have implemented a modeling system (DHSVM-RBM) within the framework of the state-space paradigm that couples a spatially distributed land surface hydrologic model, DHSVM, with the distributed stream temperature model, RBM. The basic modeling system has been applied previously to several similar-sized watersheds. However, we have made enhancements to DHSVM-RBM that simulate spatial heterogeneity and temporal variation (i.e., seasonal changes in canopy cover) in riparian vegetation, and we included additional features in DHSVM-RBM that provide the capability for simulating the impacts of reservoirs that may develop thermal stratification. We have tested the modeling system in the Farmington River basin in the Connecticut River system, which includes varying types of watershed development (e.g., deforestation and reservoirs) that can alter the streams' hydrologic regime and thermal energy budget. We evaluated streamflow and stream temperature simulations against all available observations distributed along the Farmington River basin. Results based on metrics recommended for model evaluation compare well to those obtained in similar studies. We demonstrate the way in which the model system can provide decision support for watershed planning by simulating a limited number of scenarios associated with hydrologic and land use alterations.


1999 ◽  
Vol 29 (10) ◽  
pp. 1557-1573 ◽  
Author(s):  
Robert J Pabst ◽  
Thomas A Spies

We characterized the structure and composition of unmanaged riparian forests in three river basins in Oregon's coastal mountains. Our objective was to evaluate stand attributes at three spatial scales: streamside (site), drainage network (stream order), and basin (subregion). Data on basal area, species composition, snag density, canopy cover, and tree regeneration were collected along transects at 124 sites. Conifer basal area increased with distance from stream, a trend similar among subregions, and was highest at sites along first-order streams. Hardwood basal area was relatively constant with distance from stream and was proportionally higher at sites along second- and third-order streams than at sites along first-order streams. Conifer and hardwood tree regeneration occurred infrequently and varied by topographic position, stream order, and subregion. Conifer regeneration was associated with basal area of shade-tolerant conifers and appeared to be limited by shrub competition. The unmanaged forests we studied were characterized by a patchy mosaic of structure and composition. Hardwoods and shrubs were major components of the near-stream environment in these forests, whereas dominance of conifers was limited to hillslopes. It appears that fine-scale patterns associated with proximity to the stream are influenced by coarser scale factors such as valley-floor width and climate.


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