Snow removal reduces annual cellulose decomposition in a riparian boreal forest

2013 ◽  
Vol 93 (4) ◽  
pp. 427-433 ◽  
Author(s):  
Juergen Kreyling ◽  
Mahsa Haei ◽  
Hjalmar Laudon
Keyword(s):  
Boreal Forest ◽  
Snow Cover ◽  
Boreal Forests ◽  
Soil Depth ◽  
Decomposition Rates ◽  
Soil Frost ◽  
Snow Removal ◽  
Cellulose Decomposition ◽  
Significant Difference ◽  
The Impact

Kreyling, J., Haei, M. and Laudon, H. 2013. Snow removal reduces annual cellulose decomposition in a riparian boreal forest. Can. J. Soil Sci. 93: 427–433. Decomposition is a key process in carbon and nutrient cycling. However, little is known about its response to altered winter soil temperature regimes in boreal forests. Here, the impact of soil frost on cellulose decomposition over 1 yr and soil biotic activity (bait-lamina sticks) over winter, in spring, and in summer was investigated using a long-term (9-yr) snow-cover manipulation experiment in a boreal Picea abies forest. The experiment consisted of the treatments: snow removal, increased insulation, and ambient control. The snow removal treatment caused longer and deeper soil frost (minimum temperature −8.6°C versus −1.4°C) at 10 cm soil depth in comparison with control, while the increased insulation treatment resulted in nearly no soil frost during winter. Annual cellulose decomposition rates were reduced by 46% in the snow removal manipulation in comparison with control conditions. Increased insulation had no significant effect on decomposition. The decomposition was mainly driven by microorganisms, as no significant difference was observed for containers enclosed with a 44-µm and a 1-mm mesh. Soil biotic activity was slightly increased by both the snow removal and the increased insulation treatment in comparison with control conditions over winter. However, this effect disappeared over spring and summer. We conclude that soil frost can have strong effects on decomposition in boreal ecosystems. Further studies should investigate to which degree the observed reduction in decomposition due to reduced snow cover in winter slows or even offsets the expected increase in decomposition rates with global warming.

Wildlife-mitigated precommercial thinning maintains the abundance of fruit shrubs in a boreal forest

2013 ◽  
Vol 43 (3) ◽  
pp. 306-310 ◽  
Author(s):  
Mélanie Major ◽  
André Desrochers
Keyword(s):  
Species Composition ◽  
Boreal Forest ◽  
Boreal Forests ◽  
Late Summer ◽  
Diameter Growth ◽  
Precommercial Thinning ◽  
Wildlife Species ◽  
Abundance And Distribution ◽  
And Control ◽  
The Impact

In boreal forests, fruits are an abundant resource in late summer and benefit many wildlife species. Fruits are mainly found in early successional stands, which are often subject to precommercial thinning designed to increase diameter growth of residual trees and manage stand species composition. Concerns about the consequences of precommercial thinning on wildlife have led to various methods of precommercial thinning with mitigation for wildlife. In summers 2007 and 2008, we examined the impact of wildlife-mitigated thinning on fruit shrub abundance and distribution at the Forêt Montmorency, Quebec. The abundance of fruit shrubs of all species except Amelanchier was similar in thinned and control stands but was highly variable among individual stands. Amelanchier shrubs appeared to benefit from thinning, especially 10 to 20 years after clearcutting. Fruit shrubs were highly clustered within early successional stands, but less so after thinning. We conclude that wildlife-mitigated precommercial thinning does not reduce access to fruits for birds and other frugivores and may even facilitate it in eastern Canadian boreal forests.

scholarly journals The Dynamics of Transpiration to Evapotranspiration Ratio under Wet and Dry Canopy Conditions in a Humid Boreal Forest

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 237 ◽  
Author(s):  
Bram Hadiwijaya ◽  
Steeve Pepin ◽  
Pierre-Erik Isabelle ◽  
Daniel F. Nadeau
Keyword(s):  
Boreal Forest ◽  
Sap Flow ◽  
Boreal Forests ◽  
Cold Climate ◽  
Thermal Dissipation ◽  
Evaporative Demand ◽  
Sap Flux Density ◽  
Flow Measurements ◽  
Growing Seasons ◽  
The Impact

Humid boreal forests are unique environments characterized by a cold climate, abundant precipitation, and high evapotranspiration. Transpiration ( E T ), as a component of evapotranspiration (E), behaves differently under wet and dry canopy conditions, yet very few studies have focused on the dynamics of transpiration to evapotranspiration ratio ( E T / E ) under transient canopy wetness states. This study presents field measurements of E T / E at the Montmorency Forest, Québec, Canada: a balsam fir boreal forest that receives ∼ 1600 mm of precipitation annually (continental subarctic climate; Köppen classification subtype Dfc). Half-hourly observations of E and E T were obtained over two growing seasons using eddy-covariance and sap flow (Granier’s constant thermal dissipation) methods, respectively, under wet and dry canopy conditions. A series of calibration experiments were performed for sap flow, resulting in species-specific calibration coefficients that increased estimates of sap flux density by 34 % ± 8 % , compared to Granier’s original coefficients. The uncertainties associated with the scaling of sap flow measurements to stand E T , especially circumferential and spatial variations, were also quantified. From 30 wetting–drying events recorded during the measurement period in summer 2018, variations in E T / E were analyzed under different stages of canopy wetness. A combination of low evaporative demand and the presence of water on the canopy from the rainfall led to small E T / E . During two growing seasons, the average E T / E ranged from 35 % ± 2 % to 47 % ± 3 % . The change in total precipitation was not the main driver of seasonal E T / E variation, therefore it is important to analyze the impact of rainfall at half-hourly intervals.

Diagnosing the Influence of a Receding Snow Boundary on Simulated Midlatitude Cyclones Using Piecewise Potential Vorticity Inversion

2020 ◽  
Vol 148 (11) ◽  
pp. 4479-4495
Author(s):  
Melissa L. Breeden ◽  
Ryan Clare ◽  
Jonathan E. Martin ◽  
Ankur R. Desai
Keyword(s):  
Life Cycle ◽  
Snow Cover ◽  
Potential Vorticity ◽  
Detailed Examination ◽  
Static Stability ◽  
Relative Vorticity ◽  
Surface Boundary ◽  
Snow Removal ◽  
The Impact ◽  
Midlatitude Cyclones

AbstractPrevious research has found a relationship between the equatorward extent of snow cover and low-level baroclinicity, suggesting a link between the development and trajectory of midlatitude cyclones and the extent of preexisting snow cover. Midlatitude cyclones are more frequent 50–350 km south of the snow boundary, coincident with weak maxima in the environmental Eady growth rate. The snow line is projected to recede poleward with increasing greenhouse gas emissions, possibly affecting the development and track of midlatitude cyclones during Northern Hemisphere winter. Detailed examination of the physical implications of a modified snow boundary on the life cycle of individual storms has, to date, not been undertaken. This study investigates the impact of a receding snow boundary on two cyclogenesis events using Weather Research and Forecasting Model simulations initialized with observed and projected future changes to snow extent as a surface boundary condition. Potential vorticity diagnosis of the modified cyclone simulations isolates how changes in surface temperature, static stability, and relative vorticity arising from the altered boundary affect the developing cyclone. We find that the surface warm anomaly associated with snow removal lowered heights near the center of the two cyclones investigated, strengthening their cyclonic circulation. However, the direct effect of snow removal is mitigated by the stability response and an indirect relative vorticity response to snow removal. Because of these opposing effects, it is suggested that the immediate effect of receding snow cover on midlatitude cyclones is likely minimal and depends on the stage of the cyclone life cycle.

Resilience of Alaska’s boreal forest to climatic changeThis article is one of a selection of papers from The Dynamics of Change in Alaska’s Boreal Forests: Resilience and Vulnerability in Response to Climate Warming.

2010 ◽  
Vol 40 (7) ◽  
pp. 1360-1370 ◽  
Author(s):  
F.S. Chapin ◽  
A.D. McGuire ◽  
R.W. Ruess ◽  
T.N. Hollingsworth ◽  
M.C. Mack ◽  
...  
Keyword(s):  
Rural Communities ◽  
Boreal Forest ◽  
Climate Warming ◽  
Boreal Forests ◽  
Structural Changes ◽  
Winter Season ◽  
Indigenous Communities ◽  
Structural Features ◽  
Temperature Sensitive ◽  
The Impact

This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased postfire recruitment of deciduous trees, and reduced safety of hunters traveling on river ice. These changes have modified key structural features, feedbacks, and interactions in the boreal forest, including reduced effects of upland permafrost on regional hydrology, expansion of boreal forest into tundra, and amplification of climate warming because of reduced albedo (shorter winter season) and carbon release from wildfires. Other temperature-sensitive processes for which no trends have been detected include composition of plant and microbial communities, long-term landscape-scale change in carbon stocks, stream discharge, mammalian population dynamics, and river access and subsistence opportunities for rural indigenous communities. Projections of continued warming suggest that Alaska’s boreal forest will undergo significant functional and structural changes within the next few decades that are unprecedented in the last 6000 years. The impact of these social–ecological changes will depend in part on the extent of landscape reorganization between uplands and lowlands and on policies regulating subsistence opportunities for rural communities.

scholarly journals Methane emissions from boreal and tropical forest ecosystems derived from in-situ measurements

2007 ◽  
Vol 7 (5) ◽  
pp. 14011-14039 ◽  
Author(s):  
V. Sinha ◽  
J. Williams ◽  
P. J. Crutzen ◽  
J. Lelieveld
Keyword(s):  
Boreal Forest ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Forest Ecosystem ◽  
Boreal Forests ◽  
Forest Ecosystems ◽  
Global Budget ◽  
Night Time ◽  
Mixing Ratios ◽  
The Impact

Abstract. Methane is a climatologically important greenhouse gas, which plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. Recent findings that vegetation emits methane have stimulated efforts to ascertain the impact of this source on the global budget. In this work, we present the results of high frequency (ca. 1 min−1) methane measurements conducted in the boreal forests of Finland and the tropical forests of Suriname, in April–May, 2005 and October 2005 respectively. The measurements were performed using a gas chromatograph – flame ionization detector (GC-FID). The average of the median mixing ratios during a typical diel cycle were 1.83 μmol mol−1 and 1.74 μmol mol−1 for the boreal forest ecosystem and tropical forest ecosystem respectively, with remarkable similarity in the time series of both the boreal and tropical diel profiles. Night time methane emission flux of the boreal forest ecosystem, calculated from the increase of methane during the night and measured nocturnal boundary layer heights yields a flux of (3.62±0.87)×1011 molecules cm−2 s−1(or 45.5±11 Tg CH4 yr−1 for global boreal forest area). This is a source contribution of circa 8% of the global methane budget. These results highlight the importance of the boreal and tropical forest ecosystems for the global budget of methane. The results are also discussed in the context of recent work reporting high methane mixing ratios over tropical forests using space borne near infra-red spectroscopy measurements.

scholarly journals Simulated single-layer forest canopies delay Northern Hemisphere snowmelt

2019 ◽  
Author(s):  
Markus Todt ◽  
Nick Rutter ◽  
Christopher G. Fletcher ◽  
Leanne M. Wake
Keyword(s):  
Snow Cover ◽  
Boreal Forests ◽  
Single Layer ◽  
Longwave Radiation ◽  
Length Change ◽  
Day Length ◽  
Forest Canopies ◽  
Diurnal Cycles ◽  
Community Land Model ◽  
The Impact

Abstract. Single-layer vegetation schemes have been found to overestimate diurnal cycles in longwave radiation beneath forest canopies. This study derives a correction from forest stand-scale simulations, which reduces diurnal cycles of sub-canopy longwave radiation. Correction factors are subsequently implemented in land-only simulations of the Community Land Model version 4.5 (CLM4.5) in order to assess the impact on snow cover. Nighttime underestimations of sub-canopy longwave radiation outweigh daytime overestimations, which leads to underestimated averages over the snow cover season. As a result, snow temperatures are underestimated and snowmelt is delayed in CLM4.5 across evergreen boreal forests. Increasing insolation and day length change the impact of overestimated diurnal cycles on daily average sub-canopy longwave radiation throughout the snowmelt season. Consequently, delay in snowmelt is more substantial where winters are warm and snowmelt occurs early, which results in a shortened snowmelt duration across boreal forests.

scholarly journals Model of the influence of snow cover on soil freezing

2000 ◽  
Vol 31 ◽  
pp. 417-421 ◽  
Author(s):  
N. I. Osokin ◽  
R. S. Samoylov ◽  
A.V. Sosnovskiy ◽  
S. A. Sokratov ◽  
V. A. Zhidkov
Keyword(s):  
Snow Cover ◽  
Soil Depth ◽  
Negative Temperature ◽  
Snow Accumulation ◽  
Frozen Soil ◽  
Soil Freezing ◽  
Soil Frost ◽  
Wide Range ◽  
Freezing Depth ◽  
Good Agreement

AbstractA mathematical model of snow-cover influence on soil freezing, taking into account the phase transition layer, water migration in soil, frost heave and ice-layer formation, has been developed. The modeled results are in good agreement with data observed in natural conditions. The influence of a possible delay between the time of negative temperature establishment in the air and the beginning of snow accumulation, and possible variations of the thermophysical properties of snow cover in the wide range previously reported were investigated by numerical experiments. It was found that the delay could change the frozen-soil depth up to 2–3 times, while different thermophysical characteristics of snow changed the resulting freezing depth 4–5 times.

scholarly journals Long-Term Soil Fertility and Site Productivity in Stem-Only and Whole-Tree Harvested Stands in Boreal Forest of Quebec (Canada)

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 583
Author(s):  
Rock Ouimet ◽  
Louis Duchesne ◽  
Stéphane Tremblay
Keyword(s):  
Boreal Forest ◽  
Soil Depth ◽  
Mineral Soil ◽  
Forest Biomass ◽  
Forest Harvesting ◽  
Site Productivity ◽  
Productivity Indicators ◽  
The Impact ◽  
Whole Tree

Using residual biomass from forest harvesting to produce energy is viewed increasingly as a means to reduce fossil fuel consumption. However, the impact such practices on soil and future site productivity remains a major concern. We revisited 196 forest plots that were subject to either whole-tree (WTH) or stem-only (SOH) harvesting 30 years ago in the boreal forest in Quebec, Canada. Plots were stratified by four soil regions grouped by so-called ‘soil provinces’. Soil analyses indicated that after 30 years, the forest floor of WTH sites had smaller pools of N (−8%), exchangeable Ca (−6%) and exchangeable Mn (−21%) and a higher C/N ratio (+12%) than that of SOH sites. Mineral soil responses to the two harvesting intensities differed among soil provinces. In the two coarse-textured granitic soil provinces, organic matter, organic carbon, and nitrogen pools over the whole solum (0–60 cm soil depth) were at least 28% smaller after WTH than after SOH. Site productivity indicators followed differences between soils and were lower after WTH than after SOH in the two granitic soil provinces. The study shows that soil characteristics greatly influence a soil’s sensitivity to increased forest biomass harvesting in the long term.

scholarly journals Spatial and temporal variation in weather events critical for boreal agriculture: III Frost and winter time fluctuation

2016 ◽  
Vol 25 (1) ◽  
Author(s):  
Pirjo Peltonen-Sainio ◽  
Pentti Pirinen ◽  
Mikko Laapas ◽  
Hanna M. Mäkelä ◽  
Hannu Ojanen ◽  
...  
Keyword(s):  
Snow Cover ◽  
Crop Production ◽  
Soil Depth ◽  
Meteorological Data ◽  
Spatial And Temporal Variation ◽  
Daily Maximum ◽  
Significant Shift ◽  
Deep Soil ◽  
Soil Frost ◽  
Weather Stations

In the boreal zone of Europe, differences between the four seasons are considerable. Also, the within-season variation in climatic conditions is substantial. This has many impacts on agriculture that are exceptional when compared to any other environmental zone in Europe. All the meteorological data were based on weather observations made by the Finnish Meteorological Institute. Likelihood (%) for soil frost (≤ 0 °C at 20 cm soil depth) at nine weather stations, and late snow cover (> 1 cm) (10 km × 10 km grid) were estimated for late spring. Probabilities (%) of night frost at the ground surface (March-September) were calculated at nine weather stations by frequencies of the lowest observed night-time temperature: a) between –2 and –5 °C (mild), b) ≤ –5 °C (moderate) and c) ≤ –9 °C (severe). Also, the probabilities (%) of night frost in mid-summer were estimated (≤ –1 °C for at least five hours). Furthermore, a significant shift from mild to below-freezing conditions was measured in winter as a period of at least ten days with daily maximum temperatures above 0°C followed by at least a 10-day period with daily mean temperatures below –5°C in order to characterize high fluctuating winter conditions. All these except late snow cover constitute high risks to crop production. Deep soil frost may postpone sowings, while in advanced springs, night frost may cause damage. For winter crops and perennials, shifts from mild to cold spells outside the growing season are particularly detrimental. Again the data may have many other applications beyond the assessments highlighted in this paper.

scholarly journals Soil frost affects stem diameter growth of Norway spruce with delay

Trees ◽  
2021 ◽  
Author(s):  
Tapani Repo ◽  
Timo Domisch ◽  
Jouni Kilpeläinen ◽  
Harri Mäkinen
Keyword(s):  
Snow Cover ◽  
Norway Spruce ◽  
Radial Growth ◽  
Ring Width ◽  
Forest Growth ◽  
Soil Freezing ◽  
Short Term ◽  
Soil Frost ◽  
Snow Removal ◽  
Lagged Effects

Abstract Key message A lack of snow cover and increased soil freezing may not only have short-term impacts on trees but longer-lasting lagged effects on radial growth. Abstract Soil temperature and soil frost intensity are affected by the depth of insulating snow cover and the timing of snowmelt which are predicted to change by climate warming. This may increase tree growth if there is less soil freezing or decrease growth if there is no insulating snow cover, but frost temperatures still exist. Previously, we showed that the changes in soil frost by snow manipulations in a ~ 50-year-old stand of Norway spruce [Picea abies (L.) Karst.] in eastern Finland in two winters (2005/2006 and 2006/2007) led to short-term changes in physiology, morphology, and the growth of the shoots and roots. The treatments were: (1) control with natural insulating snow accumulation and melting; (2) snow removal during winter; and (3) snow removal in winter and insulation at the top of the forest floor in late winter to delay soil thawing. In this study, we examined the lagged effects of those treatments by radial trunk increment cores during the nine-year recovery period after the termination of the treatments. Annual ring width index (AWI) was calculated for each year by normalization of the ring width in the respective year in proportion to the ring width in the last year (2005) before the treatments. No differences in AWI were found between the treatments before or during the snow manipulation period. However, differences started to appear 1 year after the treatments were finished, became significant 4 years later in 2011 and lasted for 3 years. The radial increment was lower in the treatment with snow removed than in the control and in the treatment with insulation to delay soil thawing, but there were no differences between the latter two treatments. The results indicate that a lack of snow cover may not only have short-term impacts but longer-lasting consequences on the radial growth of trees. The positive effects of prolonged growing season by the increasing summer temperatures on forest growth predicted for the boreal region may therefore not be fully realised due to the negative effects of decreased snow cover and increasing soil freezing.

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