Observed cold season changes in a Fennoscandian fell area over the past three decades

Kivinen, Sonja; Rasmus, Sirpa

doi:10.1007/s13280-014-0541-8

Cited by 22 publications

(13 citation statements)

References 49 publications

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“…The potential factors driving the canopy cover increase in the four landscapes are less evident compared to canopy cover change dynamics in Pistuacanis that could be attributed to disturbance and the following succession. Recent research conducted in the studied regions suggests that changes in forest structure that have occurred after the late 19 th century could be related to changes in climate (Aakala et al 2018;Hofgaard et al 2018, Sulla-Menashe et al 2018, as annual temperature and precipitation have significantly increased in both regions during this period of time (Yagouti et al 2007;Kivinen and Rasmus 2015). This supports the notion that the observed canopy cover increase could indeed be due to improved growth conditions.…”

Section: Large Scale Processes Drove Canopy Cover Increase In Most Lasupporting

confidence: 69%

Analyzing spatial variation and change in the structure of boreal old-growth forests

Kulha¹

2020

Diss. For.

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Global environmental change and other anthropogenic changes, such as changes in disturbance regimes alter the structure and dynamics of boreal old-growth forests (boreal forests with negligible human impact, henceforth natural boreal forests). Changes in these forests greatly influence key ecosystem properties such as biodiversity and carbon cycle. Hence, understanding the development of the remaining natural boreal forests is particularly important. This thesis examines how boreal forest structure varies in space and changes over time. Forest structure was examined in three natural boreal forest landscapes (2 km × 2 km each) in northern Fennoscandia and two landscapes in eastern North America. Canopy cover that was visually interpreted from stereopairs of aerial photographs taken between the years 1959 and 2011 was used as a surrogate measure of forest structure to quantify and examine spatial variation and/or temporal change, and Bayesian inference was used to separate credible ecological phenomena from the noise caused by visual interpretation error. This thesis presents and applies a novel methodology to study changes in forest structure. We calibrated visual canopy cover interpretations made from time series of aerial photographs with canopy cover reconstructions that were based on field-and tree-ring measurements. We successfully identified credible changes in forest structure in each studied landscape, but also noted that the visual interpretation of canopy cover was prone to systematic and random error that depended on, e.g., aerial photo quality. Due to this error, changes that occurred at the level of an individual tree could not be credibly discerned. Still, the methodology can be used to detect both abrupt and slow continuous changes in forest ecosystems. The methodology was extended to examine spatial variation in forest structure. The results revealed variation in forest structure at multiple spatial scales which showed similarities despite the differences in dominant tree species and disturbance regimes between the studied landscapes. The variability was connected with scale-dependent driving processes that also showed similarities among the landscapes. Last, the methodology was applied to study how varying scale of observation influences how changes in forest structure are perceived over different periods of time. This multi-scale change analysis revealed a synchronous and prevalent cover increase at large spatial scales in the majority of the studied landscapes, and canopy cover decrease and increase in areas that were subjects to disturbances. Changes of variable direction and magnitude were detected at smaller spatial scales in each studied landscape. The results indicated that historical aerial photographs are a valuable resource in studying how forest ecosystems develop, but the notable errors in their visual interpretation need to be taken into account in analysis of change. The results aligned with the hierarchy theory and the hierarchical patch dynamics concept by showing that the structur...

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Section: Large Scale Processes Drove Canopy Cover Increase In Most Lasupporting

confidence: 69%

Analyzing spatial variation and change in the structure of boreal old-growth forests

Kulha¹

2020

Diss. For.

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“…The formation of the snow cover during the autumn is considered crucial for all winter conditions. During unstable early winter with several 0-degree days, there is a high probability of icy snow cover or ground ice formation that prevents reindeer access to lichens [33][34][35]38]. Warmer and wetter winters have been reported to decrease reindeer condition and productivity and increase their mortality in Nordic countries and Russia.…”

Section: Discussionmentioning

confidence: 99%

Long-Term Climate Trends and Extreme Events in Northern Fennoscandia (1914–2013)

Kivinen

Rasmus

Jylhä

et al. 2017

Climate

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Abstract:We studied climate trends and the occurrence of rare and extreme temperature and precipitation events in northern Fennoscandia in 1914Fennoscandia in -2013. Weather data were derived from nine observation stations located in Finland, Norway, Sweden and Russia. The results showed that spring and autumn temperatures and to a lesser extent summer temperatures increased significantly in the study region, the observed changes being the greatest for daily minimum temperatures. The number of frost days declined both in spring and autumn. Rarely cold winter, spring, summer and autumn seasons had a low occurrence and rarely warm spring and autumn seasons a high occurrence during the last 20-year interval (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013), compared to the other 20-year intervals. That period was also characterized by a low number of days with extremely low temperature in all seasons (4%-9% of all extremely cold days) and a high number of April and October days with extremely high temperature (36%-42% of all extremely warm days). A tendency of exceptionally high daily precipitation sums to grow even higher towards the end of the study period was also observed. To summarize, the results indicate a shortening of the cold season in northern Fennoscandia. Furthermore, the results suggest significant declines in extremely cold climate events in all seasons and increases in extremely warm climate events particularly in spring and autumn seasons.

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“…The latter is particularly true for mountains in Romania (Birsan and Dumitrescu, 2014;Micu, 2009), Bulgaria (Brown and Petkova, 2007), Poland (Falarz, 2008), and Croatia (Gajić-Čapka, 2011). The observed changes in snow depth and snow duration are mainly caused by a shift from solid to liquid precipitation (Serquet et al, 2011;Nikolova et al, 2013) and by more frequent and more intense melt (Klein et al, 2016), both resulting from higher air temperatures during winter and spring. In addition to a general warming trend, large-scale atmospheric circulation patterns such as the North Atlantic Oscillation (NAO) have been shown to influence the snow cover in Europe (Henderson and Leathers, 2010;Bednorz, 2011;Skaugen et al, 2012;Birsan and Dumitrescu, 2014;Buisan et al, 2015).…”

Section: Observed Changes Of the Snow Covermentioning

confidence: 99%

The European mountain cryosphere: a review of its current state, trends, and future challenges

et al. 2018

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Abstract. The mountain cryosphere of mainland Europe is recognized to have important impacts on a range of environmental processes. In this paper, we provide an overview on the current knowledge on snow, glacier, and permafrost processes, as well as their past, current, and future evolution. We additionally provide an assessment of current cryosphere research in Europe and point to the different domains requiring further research. Emphasis is given to our understanding of climate–cryosphere interactions, cryosphere controls on physical and biological mountain systems, and related impacts. By the end of the century, Europe's mountain cryosphere will have changed to an extent that will impact the landscape, the hydrological regimes, the water resources, and the infrastructure. The impacts will not remain confined to the mountain area but also affect the downstream lowlands, entailing a wide range of socioeconomical consequences. European mountains will have a completely different visual appearance, in which low- and mid-range-altitude glaciers will have disappeared and even large valley glaciers will have experienced significant retreat and mass loss. Due to increased air temperatures and related shifts from solid to liquid precipitation, seasonal snow lines will be found at much higher altitudes, and the snow season will be much shorter than today. These changes in snow and ice melt will cause a shift in the timing of discharge maxima, as well as a transition of runoff regimes from glacial to nival and from nival to pluvial. This will entail significant impacts on the seasonality of high-altitude water availability, with consequences for water storage and management in reservoirs for drinking water, irrigation, and hydropower production. Whereas an upward shift of the tree line and expansion of vegetation can be expected into current periglacial areas, the disappearance of permafrost at lower altitudes and its warming at higher elevations will likely result in mass movements and process chains beyond historical experience. Future cryospheric research has the responsibility not only to foster awareness of these expected changes and to develop targeted strategies to precisely quantify their magnitude and rate of occurrence but also to help in the development of approaches to adapt to these changes and to mitigate their consequences. Major joint efforts are required in the domain of cryospheric monitoring, which will require coordination in terms of data availability and quality. In particular, we recognize the quantification of high-altitude precipitation as a key source of uncertainty in projections of future changes. Improvements in numerical modeling and a better understanding of process chains affecting high-altitude mass movements are the two further fields that – in our view – future cryospheric research should focus on.

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Observed cold season changes in a Fennoscandian fell area over the past three decades

Cited by 22 publications

References 49 publications

Analyzing spatial variation and change in the structure of boreal old-growth forests

Analyzing spatial variation and change in the structure of boreal old-growth forests

Long-Term Climate Trends and Extreme Events in Northern Fennoscandia (1914–2013)

The European mountain cryosphere: a review of its current state, trends, and future challenges

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