Role of Major Forest Biomes in Climate Change Mitigation …
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Pravalie 2018). Extremely severe droughts have the potential to cause mortality
in huge trees, possibly due to hydraulic failure (hindering water transport through
xylem by forming air bubbles) and carbon starvation (due to the closing of stomata)
(Corlett 2018). Effects of short-term drought are reversible, provided normal rainfall
prevails in the subsequent years. However, multiple, and long-term droughts can have
severe and irreversible consequences. It leads to altered species composition, with
drought-tolerant species being favoured more (Corlett 2018).
The synergistic effect of high temperature and drought increases fuel loads for
forest fires and thus, the fire frequency (Kasischke and Turetsky 2006; Pecl et al.
2017). Often, the prevalence of dry atmospheric conditions and adequate fuel loads,
especially in regions with semi-arid and sub-humid climatic conditions, act as the
main trigger for forest fire (Pravalie 2018). Natural forest fires play a crucial role in
maintaining the horizontal and vertical structures of the forest, nutrient cycling, plant
diversity, etc. (Thonicke et al. 2001; Hurteau et al. 2014; de la Barrera et al. 2018) and
therefore mediates several ecological processes. However, when natural fire regime
gets altered due to climate change and global warming, the consequences are often
drastic. A forest fire not only alters ecosystem functions and releases the stored
carbon dioxide, but also emits particulate matter (Price et al. 2012; de la Barrera
et al. 2018), detrimental to both biodiversity and proximal human habitations. Fires
in Amazonia lead to the loss of 12–30% of the live aboveground biomass, 23–31% of
canopy cover and caused 226–462% of the tree mortality (Brando et al. 2014; Pravalie
2018). Aerosol particles emitted from the forest fires tend to scatter the incoming
solar radiation and therefore affect the uplifting of water vapour (Tosca et al. 2010;
Ellison et al. 2017). Besides, the black carbon aerosol particles, when accumulated
on ice and snow decreases albedo and increase the air temperature (Randerson et al.
2006; Pravalie 2018). Megafires cause tremendous loss to both life and property,
besides affecting ecosystem services (Hurteau et al. 2014; de la Barrera et al. 2018).
In the case of prevalence of an intermediate level of rainfall, forest fire acts as a
strong predictor of the spatial distribution of forests and savannahs as the presence
of forest fire leads to open canopies and savannahs, while the absence of a forest
fire leads to closed canopies and the expansion of forest tree cover (Pravalie 2018).
Since it is expected that climate change would increase drought and desertification,
there exists a high risk for the occurrence of forest fires in the future.
2.5 Disease Outbreaks
Climate change remains a big threat to forest ecosystems by causing drought stress
to plants and greater surviving potential to insects during winter, due to increased
temperatures (Raffa et al. 2008; Grimm et al. 2013). The innate resistance of trees to
defend itself against the pest or pathogenic attack is lessened due to drought stress
(Kurz et al. 2008; Brecka et al. 2018). Disease outbreaks due to insects are very high
in boreal forests because the lifecycles of insects have been extended in these high
latitude ecosystems due to global warming, affecting trees in the growing season
489
Pravalie 2018). Extremely severe droughts have the potential to cause mortality
in huge trees, possibly due to hydraulic failure (hindering water transport through
xylem by forming air bubbles) and carbon starvation (due to the closing of stomata)
(Corlett 2018). Effects of short-term drought are reversible, provided normal rainfall
prevails in the subsequent years. However, multiple, and long-term droughts can have
severe and irreversible consequences. It leads to altered species composition, with
drought-tolerant species being favoured more (Corlett 2018).
The synergistic effect of high temperature and drought increases fuel loads for
forest fires and thus, the fire frequency (Kasischke and Turetsky 2006; Pecl et al.
2017). Often, the prevalence of dry atmospheric conditions and adequate fuel loads,
especially in regions with semi-arid and sub-humid climatic conditions, act as the
main trigger for forest fire (Pravalie 2018). Natural forest fires play a crucial role in
maintaining the horizontal and vertical structures of the forest, nutrient cycling, plant
diversity, etc. (Thonicke et al. 2001; Hurteau et al. 2014; de la Barrera et al. 2018) and
therefore mediates several ecological processes. However, when natural fire regime
gets altered due to climate change and global warming, the consequences are often
drastic. A forest fire not only alters ecosystem functions and releases the stored
carbon dioxide, but also emits particulate matter (Price et al. 2012; de la Barrera
et al. 2018), detrimental to both biodiversity and proximal human habitations. Fires
in Amazonia lead to the loss of 12–30% of the live aboveground biomass, 23–31% of
canopy cover and caused 226–462% of the tree mortality (Brando et al. 2014; Pravalie
2018). Aerosol particles emitted from the forest fires tend to scatter the incoming
solar radiation and therefore affect the uplifting of water vapour (Tosca et al. 2010;
Ellison et al. 2017). Besides, the black carbon aerosol particles, when accumulated
on ice and snow decreases albedo and increase the air temperature (Randerson et al.
2006; Pravalie 2018). Megafires cause tremendous loss to both life and property,
besides affecting ecosystem services (Hurteau et al. 2014; de la Barrera et al. 2018).
In the case of prevalence of an intermediate level of rainfall, forest fire acts as a
strong predictor of the spatial distribution of forests and savannahs as the presence
of forest fire leads to open canopies and savannahs, while the absence of a forest
fire leads to closed canopies and the expansion of forest tree cover (Pravalie 2018).
Since it is expected that climate change would increase drought and desertification,
there exists a high risk for the occurrence of forest fires in the future.
2.5 Disease Outbreaks
Climate change remains a big threat to forest ecosystems by causing drought stress
to plants and greater surviving potential to insects during winter, due to increased
temperatures (Raffa et al. 2008; Grimm et al. 2013). The innate resistance of trees to
defend itself against the pest or pathogenic attack is lessened due to drought stress
(Kurz et al. 2008; Brecka et al. 2018). Disease outbreaks due to insects are very high
in boreal forests because the lifecycles of insects have been extended in these high
latitude ecosystems due to global warming, affecting trees in the growing season