Growing Season Length as a Key Factor of Cumulative Net Ecosystem Exchange Over the Pine Forest Ecosystems in Europe

Abstract

A b s t r a c t. The Scots pine is one of the most important species in European and Asian forests. Due to a widespread occurrence of pine forests, their significance in the energy and mass exchange between the Earth surface and the atmosphere is also important, particularly in the context of climate change and greenhouse gases balance. The aim of this work is to present the relationship between the average annual net ecosystem productivity and growing season length, latitude and air temperature (tay) over Europe. Therefore, CO 2 flux measurement data from eight European pine dominated forests were used. The observations suggest that there is a correlation between the intensity of CO 2 uptake or emission by a forest stand and the above mentioned parameters. Based on the obtained results, all of the selected pine forest stands were CO 2 sinks, except a site in northern Finland. The carbon dioxide uptake increased proportionally with the increase of growing season length (9.212 g C m -2 y -1 per day of growing season, R 2 = 0.53, p = 0.0399). This dependency showed stronger correlation and higher statistical significance than both relationships between annual net ecosystem productivity and air temperature (R 2 = 0.39, p = 0.096) and annual net ecosystem productivity and latitude (R 2 = 0.47, p = 0.058). The CO 2 emission surpassed assimilation in winter, early spring and late autumn. Moreover, the appearance of late, cold spring and early winter, reduced annual net ecosystem productivity. Therefore, the growing season length can be considered as one of the main factor affecting the annual carbon budget of pine forests.

Net ecosystem productivity and its environmental controls in a mature Scots pine stand in north-western Poland

“…Even at the warmest and wettest southern sites, San Rossore (Italy) and Le Bray (France), where forest stands dominated by maritime pine are in the same age class as our stand, and with at least two times higher LAI, the mean annual NEP values were 28 and 44% lower, respectively. These differences are due to the high GEP in the Tuczno forest, with mean annual R not remarkably different between our stand and the other sites mentioned above (see Table 1 in Danielewska et al, 2015).…”

“…2001; Pilegaard et al, 2001;Kolari et al, 2004;Zielis et al, 2014;Danielewska et al, 2015). Furthermore, according to comprehensive quantification of the C balance of different forests, using EC and biometric measurements, temperate evergreen forests sequester from 133 ± 47 up to 389 ± 42 g C m −2 y −1 depending on climatic conditions (Luyssaert et al, 2007).…”

Divergent carbon cycle response of forest and grass‐dominated northern temperate ecosystems to record winter warming

“…Moreover, the timing of critical springtime transitions, such as snow melt, soil thaw, and leaf-out are altered (Contosta et al, 2017). The timing and order of these vernal transitions have substantial influence on interannual variability in productivity and C sequestration (Danielewska, Urbaniak, & Olejnik, 2015;Hufkens et al, 2016;Keenan et al, 2014;Ouimette et al, 2018;Richardson et al, 2013).…”

“…While there has been considerable interest in how earlier springs will affect annual C exchange through extended growing seasons, the directional effects of warm winters and early vernal transitions on C uptake and loss during the winter to spring transition have not been consistent across studies or vegetation types. Warm winters with early snowmelt often lead to longer growing seasons, which can enhance annual ecosystem C uptake (Danielewska et al, 2015;Delpierre et al, 2009;Galvagno et al, 2013;Keenan et al, 2014;Pulliainen et al, 2017;Wolf et al, 2016). However, the early loss of snow can also lead to photosynthesis occurring during unfavorable conditions (Winchell, Barnard, Monson, Burns, & Molotch, 2016), arrested physiological development of vegetation (Galvagno et al, 2013), or enhanced water stress (Arnone et al, 2008;Hu, Moore, Burns, & Monson, 2010) that offset C gains from the elongated growing season.…”

Functioning of reclaimed oil sands ecosystems and the implications for reclamation certification

“…June-August NEP increased from -117 to 202 g C m -2 over three years and corresponded to the increase in annual values from -242 to 77 g C m -2 year -1 (Clark, 2018). The relationship between growing season GPP and annual NEP has been noted via the significance of growing season length on annual NEP at North American boreal (mixed-wood and Jack pine) and European (Scots pine) forests (Zha et al, 2009;Danielewska et al, 2015;Froelich et al, 2015). Although there is no direct mechanism to offset emissions using reclaimed ecosystem CO2 uptake, the carbon budget of these reclaimed ecosystems and how they develop post-construction is of relevance for efforts to anticipate how Canadian forests will react to climate change (Kurz et al, 2008).…”