Role of Major Forest Biomes in Climate Change Mitigation …
501
forests ranges between −30 and 30 °C and the precipitation ranges from 500 mm to
1500 mm (Martin et al. 2001; Lorenz and Lal 2010; Tyrrell et al. 2012). These forests
are less diverse than tropical forests, but more diverse than boreal forests (Lorenz
and Lal 2010; Hui et al. 2017). Although temperate forests have less diversity, they
are prominently recognized to possess some of the world’s tallest trees like Sequoia
sempervirens (Pan et al. 2013; Pravalie 2018).
Temperate forests occupy a prominent place in the global carbon cycle, although
it is the smallest of all the three discussed forest biomes (Reich and Bolstad 2001;
Lorenz and Lal 2010) as they account for approximately 13.8% of the terrestrial
carbon sink (Robinson 2007). As per Dixon et al. (1994), temperate forests store
59 Gt C in vegetation and 100 Gt C in soil. Temperate forests contain 109 Pg C
in aboveground biomass and 49 Pg C in belowground biomass (Robinson 2007).
Overall, it has been estimated that temperate forests store 73–159 Pg C in vegetation
and 153–195 Pg C in soil up to a depth of 1 m (Robinson 2007; Lorenz and Lal
2010). According to Bonan (2008), temperate forests account for 20% of the global
vegetation biomass and 10% of the terrestrial carbon. Pan et al. (2011) estimated
that temperate forests contain about 119 Pg C, which is 14% of the carbon stored in
world’s forests. Temperate forests act as an important carbon sink as they sequester
about 0.2–0.4 Pg C every year and they are known to have high productivity and
high resilience in the event of a disturbance (Tyrrell et al. 2012). The major carbon
sequestering pool in temperate forests is the tree biomass, although the other biomass
pools such as understorey, detritus and litter also contribute substantially (Whittaker
and Woodwell 1986; Son et al. 2001; Peichl and Arain 2006; Dar and Sundarapandian
2015). Tree species composition greatly influences the carbon storage potential of
temperate forests and typically, biomass and carbon accumulation increases with
stand age (Chen et al. 2011; Wei et al. 2013; Dar and Sundarapandian 2015). The
carbon storage is usually low in younger stands and high in older stands due to
longer period of biomass accumulation and the older stands usually hold two to
five times more carbon than the younger stands (Pregitzer and Euskirchen 2004;
Peichl and Arain 2006; Tyrrell et al. 2012). The carbon pools of temperate forests
are strongly regulated by stand age, size class of trees, elevation, forest composition,
etc. (Pregitzer and Euskirchen 2004; Wang et al. 2014; Dar et al. 2017).
Photosynthesis is the main mechanism that essentially regulates the carbon uptake
by trees and the optimum temperature for photosynthesis in temperate forests is 5–
20 °C, which usually occurs during spring (Malhi et al. 1999; Tyrrell et al. 2012).
Temperate forests show an increase in annual productivity due to increase in spring
temperatures, caused due to global warming (Saigusa et al. 2008; Tyrrell et al. 2012).
In case of occurrence of severe and recurrent droughts during summer, there would
be tree mortality, resulting in carbon loss (Breda et al. 2006; Lorenz and Lal 2010).
Water availability is a crucial determinant of carbon stocks as it exerts control over
tree growth as well as tree species distribution (Hinckley et al. 1981; Tyrrell et al.
2012). Water deficit and therefore drought stress, in the presence of elevated carbon
dioxide concentration could significantly alter the process of gas exchange and reduce
the tree growth (Tschaplinski et al. 1995; Tyrrell et al. 2012), by causing stomatal
closure and hindering carbon uptake (Hinckley et al. 1981; Jarvis 1989). Therefore, at
501
forests ranges between −30 and 30 °C and the precipitation ranges from 500 mm to
1500 mm (Martin et al. 2001; Lorenz and Lal 2010; Tyrrell et al. 2012). These forests
are less diverse than tropical forests, but more diverse than boreal forests (Lorenz
and Lal 2010; Hui et al. 2017). Although temperate forests have less diversity, they
are prominently recognized to possess some of the world’s tallest trees like Sequoia
sempervirens (Pan et al. 2013; Pravalie 2018).
Temperate forests occupy a prominent place in the global carbon cycle, although
it is the smallest of all the three discussed forest biomes (Reich and Bolstad 2001;
Lorenz and Lal 2010) as they account for approximately 13.8% of the terrestrial
carbon sink (Robinson 2007). As per Dixon et al. (1994), temperate forests store
59 Gt C in vegetation and 100 Gt C in soil. Temperate forests contain 109 Pg C
in aboveground biomass and 49 Pg C in belowground biomass (Robinson 2007).
Overall, it has been estimated that temperate forests store 73–159 Pg C in vegetation
and 153–195 Pg C in soil up to a depth of 1 m (Robinson 2007; Lorenz and Lal
2010). According to Bonan (2008), temperate forests account for 20% of the global
vegetation biomass and 10% of the terrestrial carbon. Pan et al. (2011) estimated
that temperate forests contain about 119 Pg C, which is 14% of the carbon stored in
world’s forests. Temperate forests act as an important carbon sink as they sequester
about 0.2–0.4 Pg C every year and they are known to have high productivity and
high resilience in the event of a disturbance (Tyrrell et al. 2012). The major carbon
sequestering pool in temperate forests is the tree biomass, although the other biomass
pools such as understorey, detritus and litter also contribute substantially (Whittaker
and Woodwell 1986; Son et al. 2001; Peichl and Arain 2006; Dar and Sundarapandian
2015). Tree species composition greatly influences the carbon storage potential of
temperate forests and typically, biomass and carbon accumulation increases with
stand age (Chen et al. 2011; Wei et al. 2013; Dar and Sundarapandian 2015). The
carbon storage is usually low in younger stands and high in older stands due to
longer period of biomass accumulation and the older stands usually hold two to
five times more carbon than the younger stands (Pregitzer and Euskirchen 2004;
Peichl and Arain 2006; Tyrrell et al. 2012). The carbon pools of temperate forests
are strongly regulated by stand age, size class of trees, elevation, forest composition,
etc. (Pregitzer and Euskirchen 2004; Wang et al. 2014; Dar et al. 2017).
Photosynthesis is the main mechanism that essentially regulates the carbon uptake
by trees and the optimum temperature for photosynthesis in temperate forests is 5–
20 °C, which usually occurs during spring (Malhi et al. 1999; Tyrrell et al. 2012).
Temperate forests show an increase in annual productivity due to increase in spring
temperatures, caused due to global warming (Saigusa et al. 2008; Tyrrell et al. 2012).
In case of occurrence of severe and recurrent droughts during summer, there would
be tree mortality, resulting in carbon loss (Breda et al. 2006; Lorenz and Lal 2010).
Water availability is a crucial determinant of carbon stocks as it exerts control over
tree growth as well as tree species distribution (Hinckley et al. 1981; Tyrrell et al.
2012). Water deficit and therefore drought stress, in the presence of elevated carbon
dioxide concentration could significantly alter the process of gas exchange and reduce
the tree growth (Tschaplinski et al. 1995; Tyrrell et al. 2012), by causing stomatal
closure and hindering carbon uptake (Hinckley et al. 1981; Jarvis 1989). Therefore, at