Role of Major Forest Biomes in Climate Change Mitigation …
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7.3 Boreal Forests
The boreal forest biome is the world’s second largest biome, which provides a wide
range of ecosystem services, the most important of which is the timber supply (Astrup
et al. 2018). These are located between 50 and 60° N and covering an area of about
1.2 billion hectares, constituting about 30% of the most globally densely forested
area (Crowther et al. 2015; Hui et al. 2017; Brecka et al. 2018). The boreal forest
biome is the youngest of all the major forest biomes and it has about 48% of the
world’s relatively undisturbed forest (Bryant et al. 1997; Taggart and Cross 2009;
Lorenz and Lal 2010). The mean annual temperature in this biome ranges from −10
to 5 °C and the annual precipitation is usually less than 500 mm and is mainly in the
form of snow (Hui et al. 2017; Pravalie 2018). They are characterized by short and
moderately warm summers, and long and cold winters (Hui et al. 2017), as a result,
the tree growth rate is very low due to the short growing season (Kellomaki 2000;
Brecka et al. 2018). With poor tree diversity (Pravalie 2018), they are distinguished
by the presence of spiral canopies (Landsberg and Gower 1997; Lorenz and Lal
2010). Another major feature of this biome is that soils are very deeply frozen by
permafrost, hampering both root development and soil water drainage (Camill 2005;
Lorenz and Lal 2010).
Boreal forest biome is known to contain highest amount of carbon than the tropical
and temperate forest biomes and it contributes largely to the terrestrial carbon sink
(Denman et al. 2007; Bonan 2008; Hui et al. 2017). However, the boreal forest biome
holds only the second largest quantity of carbon, next to the tropical forest biome
(Pan et al. 2011; Astrup et al. 2018). The rates of decomposition is very slow due
to short summers (Hui et al. 2017), which enhances the soil carbon sink. It has been
estimated that around 84% of the boreal forest carbon lies in the soils and only less
than one-sixth occurs in the vegetation biomass (Hui et al. 2017). As per Dixon et al.
(1994), boreal forests store 88 Gt C in vegetation and 471 Gt C in soil. In general,
boreal forests are expected to hold between 78 and 143 Pg C in vegetation and roughly
around 338 Pg C in soils, up to a depth of 1 m (Robinson 2007). Around 42 Pg C and
15 Pg C are stored in the aboveground biomass and belowground biomass of boreal
forests (Lorenz and Lal 2010). Pan et al. (2011) estimated that boreal forests contain
about 272 Pg C, which accounts for 32% of the carbon stored in world’s forests.
Lichens and bryophytes are particularly important in the boreal forest biome
because they play an important role in the boreal forest carbon cycle by influencing
carbon storage as well as release. Lichen and bryophyte tissues form a dense mat in
the ground layer of boreal forests and these tissues decompose more slowly than the
fallen woody debris (Turetsky 2003; Milakovsky et al. 2012). Also, thick mats of
mosses can limit the heat gained from the atmosphere (Startsev et al. 2007). On the
other hand, when they dry out, they may act as fuel loads for forest fires, due to their
flammability (Harden et al. 1997). Fire plays an important role in the boreal forest
biome as it is responsible for transferring huge amounts of carbon from vegetation
503
7.3 Boreal Forests
The boreal forest biome is the world’s second largest biome, which provides a wide
range of ecosystem services, the most important of which is the timber supply (Astrup
et al. 2018). These are located between 50 and 60° N and covering an area of about
1.2 billion hectares, constituting about 30% of the most globally densely forested
area (Crowther et al. 2015; Hui et al. 2017; Brecka et al. 2018). The boreal forest
biome is the youngest of all the major forest biomes and it has about 48% of the
world’s relatively undisturbed forest (Bryant et al. 1997; Taggart and Cross 2009;
Lorenz and Lal 2010). The mean annual temperature in this biome ranges from −10
to 5 °C and the annual precipitation is usually less than 500 mm and is mainly in the
form of snow (Hui et al. 2017; Pravalie 2018). They are characterized by short and
moderately warm summers, and long and cold winters (Hui et al. 2017), as a result,
the tree growth rate is very low due to the short growing season (Kellomaki 2000;
Brecka et al. 2018). With poor tree diversity (Pravalie 2018), they are distinguished
by the presence of spiral canopies (Landsberg and Gower 1997; Lorenz and Lal
2010). Another major feature of this biome is that soils are very deeply frozen by
permafrost, hampering both root development and soil water drainage (Camill 2005;
Lorenz and Lal 2010).
Boreal forest biome is known to contain highest amount of carbon than the tropical
and temperate forest biomes and it contributes largely to the terrestrial carbon sink
(Denman et al. 2007; Bonan 2008; Hui et al. 2017). However, the boreal forest biome
holds only the second largest quantity of carbon, next to the tropical forest biome
(Pan et al. 2011; Astrup et al. 2018). The rates of decomposition is very slow due
to short summers (Hui et al. 2017), which enhances the soil carbon sink. It has been
estimated that around 84% of the boreal forest carbon lies in the soils and only less
than one-sixth occurs in the vegetation biomass (Hui et al. 2017). As per Dixon et al.
(1994), boreal forests store 88 Gt C in vegetation and 471 Gt C in soil. In general,
boreal forests are expected to hold between 78 and 143 Pg C in vegetation and roughly
around 338 Pg C in soils, up to a depth of 1 m (Robinson 2007). Around 42 Pg C and
15 Pg C are stored in the aboveground biomass and belowground biomass of boreal
forests (Lorenz and Lal 2010). Pan et al. (2011) estimated that boreal forests contain
about 272 Pg C, which accounts for 32% of the carbon stored in world’s forests.
Lichens and bryophytes are particularly important in the boreal forest biome
because they play an important role in the boreal forest carbon cycle by influencing
carbon storage as well as release. Lichen and bryophyte tissues form a dense mat in
the ground layer of boreal forests and these tissues decompose more slowly than the
fallen woody debris (Turetsky 2003; Milakovsky et al. 2012). Also, thick mats of
mosses can limit the heat gained from the atmosphere (Startsev et al. 2007). On the
other hand, when they dry out, they may act as fuel loads for forest fires, due to their
flammability (Harden et al. 1997). Fire plays an important role in the boreal forest
biome as it is responsible for transferring huge amounts of carbon from vegetation