Abstract:
Plants encounter several biotic and abiotic stresses, usually in combination. This results in
major economic losses in agriculture and forestry every year. Climate change aggravates
the adverse effects of combined stresses and increases such losses. Trees suffer even more
from the recurrence of biotic and abiotic stress combinations owing to their long lifecycle.
Despite the effort to study the damage from individual stress factors, less attention has been
given to the effect of the complex interactions between multiple biotic and abiotic stresses.
In this review, we assess the importance, impact, and mitigation strategies of climate change
driven interactions between biotic and abiotic stresses in forestry. The ecological and
economic importance of biotic and abiotic stresses under different combinations is highlighted
by their contribution to the decline of the global forest area through their direct and indirect
roles in forest loss and to the decline of biodiversity resulting from local extinction of
endangered species of trees, emission of biogenic volatile organic compounds, and reduction
in the productivity and quality of forest products and services. The abiotic stress factors
such as high temperature and drought increase forest disease and insect pest outbreaks,
decrease the growth of trees, and cause tree mortality. Reports of massive tree mortality
events caused by “hotter droughts” are increasing all over the world, affecting several genera
of trees including some of the most important genera in plantation forests, such as Pine,
Poplar, and Eucalyptus. While the biotic stress factors such as insect pests, pathogens,
and parasitic plants have been reported to be associated with many of these mortality
events, a considerable number of the reports have not taken into account the contribution
of such biotic factors. The available mitigation strategies also tend to undermine the interactive
effect under combined stresses. Thus, this discussion centers on mitigation strategies based
on research and innovation, which build on models previously used to curb individual stresses.
