Climate change is one of the world’s greatest challenges and creates effects on forest ecosystem. Forest ecosystems are sensitive to climate thus; climate change has significant effects on species distributions, the growth rate and structure of forests. Changes in climate are strongly affect forest ecosystem by altering the growth, mortality and reproduction of trees. Increasing temperatures changes the timing of life cycle events (phenology), with earlier bud burst, leafing and flowering in trees. This review focuses on the effect of climate change on forest ecosystems. Climate change alters and shifts forest ecosystems both directly and indirectly. Warming temperature directly affects rate of plant photosynthesis and respiration processes, also indirectly by increasing the risk of infestation. Climate change can modify disturbance regimes that affect the carbon cycle, forest structure, species composition, and alter forest ecosystem function. Disturbances such as fire, species invasions, insect and disease outbreaks are disrupting the structure, composition and function of forest ecosystem. Fire effect on forest ecosystem includes; disturbance of wild life habitat, acceleration of nutrient cycling, and mortality of individual trees. The frequency, size, intensity, seasonality, and type of fires depend on the amount and frequency of precipitation in addition to forest structure and composition. Many pests and pathogens will reproduce more quickly, expand their ranges and invade new regions under warmer, wetter, or carbon dioxide enriched conditions. Increasing temperature has an effect on nutrient availability in the soil through the stimulation of organic matter decomposition and mineralization of soil nutrients.
Climate is the primary force shaping the major biomes (such as forests, grasslands, etc.) of the world . The world’s climate is changing, thus changes in the climate are likely to strongly affect forest ecosystems by altering the growth, mortality and reproduction of trees. Ecosystem services (supporting, regulating, provisioning and cultural services) are the benefits people derive from the natural processes that sustain ecosystems. These ecosystem services comprise both goods and processes are currently affected by climate change. At present global climate change shows a general increase in temperatures and levels of atmospheric carbon dioxide as well as changes in precipitation. The host physiology and defenses, relationships between pests, their environment and other species such as natural enemies, competitors and mutualists are affected when climate changed . Climate variation produces detectable effects on tree and sapling growth in natural forests.
Warmer temperatures change the timing of life cycle events (phenology), with earlier bud burst, leafing and flowering in trees, although there is much year-to-year and regional variation. It will affect forests also indirectly by increasing the risk of infestation . Effects of climate change on forest ecosystems mainly address the role of the latter with regard
to carbon emission and sequestration . It also alters the frequency and/or severity of natural disturbances in some forests, particularly fire and insect disturbances. In many forest ecosystems disturbance regimes have changed in recent years and expected to be among the most profound effect that climate change will have in the coming decades .
Increases in disturbance severities could have dramatic effect on forest ecosystem structures, species composition, and their ability to act as carbon sinks . Disturbances such as fire, drought, species invasions, insect and disease outbreaks, and storms such as hurricanes are disrupting the structure, composition and function of forest ecosystem, community or population, and change resource availability or the physical environment. There is evidence resulting in increased forest damage, erosion and landslides, with wetter soils and flooding over the last century . Climate change can affect nutrient cycling directly through its impact on temperature and precipitation. The productivity and integrity of forest ecosystems is linked to the supply of nutrients and climate change can influence nutrient dynamics by altering the rate of litter decomposition.
The potential of ecosystems to take up carbon is constrained by the availability of nitrogen and it is a basic element that is fundamental to the growth of plants. Nitrogen limits forest
growth under most conditions. Too much nitrogen, however, can
have detrimental effects on soil, trees, or indirectly through its
impacts on forest composition, growing season length, and the
water cycle. The major objective of this paper is to collate and
review much of the current information and scientific -literature
on the effect of climate change on forests and forest ecosystems.
Climate change can modify a disturbance regime that affects
forest ecosystem structure and function. The change in forest
structure and function are disrupted when disturbances exceed
their natural range of variation. Natural disturbances, such as
fires, insect outbreaks and wind throws are an integral part
of ecosystem dynamics in forests around the globe. Warming
climates pose significant threats to forest ecosystems . It may
increase mortality in older forests stressed by low soil moisture.
A gradual increase in temperature will alter the regeneration
and growth of some species. Regeneration of tree species
is affected by low soil moisture and competition with other
species during the seedling stage as the temperature increase.
Climatic variability and change results degradation of the forest
resources to emission of carbon dioxide in the atmosphere
and affecting the forest resources and its ability to deliver its
ecosystem services .
Increases in temperatures create conditions that dramatically
elevate the risk and severity of forest fires. Fire effect on forest
ecosystem includes; disturbance of wild life habitat, acceleration
of nutrient cycling, and mortality of individual trees. The
frequency, size, intensity, seasonality, and type of fires depend
on the amount and frequency of precipitation in addition to
forest structure and composition. Fire is a major control of forest
carbon balance and reduces the strength of forests carbon sinks
. The forest wildfires loss most soil nutrients and it has effect
on the available macronutrient concentrations.
Climate change is increasing the likelihood of fire ignition
and propagation such as, extreme temperatures and plant
biomass accumulation, but these are possibly interacting with
socio-economic factors . Forest fires directly a loss of habitat,
kill plants and animals in forest ecosystem. The potential
for prescribed fire to mitigate nitrogen saturation resulting
from atmospheric deposition and disturbances that can cause
comparable nutrient loss in such a short amount of time .
Climate change will have the effect of increasing the extent,
frequency, and severity of invasive species, as well as facilitating
a shift toward invasion in species that have not historically been
invasive. It creates a favorable condition for invasive species
to invade the forest ecosystem. The removal of temperature or
moisture constraints to dispersal and survival lead to changes
in the distributions of species and successfully invade new
areas . Species range shifts will also lead to becoming rare
and creates ecological space for non-native invasive species to
increase in abundance and move in. Invasive species show a
greater response to increased carbon dioxide than non-invaders.
Invasive species have strong dispersal abilities and broad
environmental tolerances, which will allow them to cope with
Invasive plants are recent introductions of non-indigenous
or exotic species that are successfully spread into new localized
natural habitats to cause economic or environmental harm.
Change in weather events increases the disturbance regime, and
invasive species generally, thrive in disturbed landscapes with
high light availability and fragmented native communities .
Forest ecosystem pests and pathogens are likely to increase,
either through the direct effect of climate change on their
abundance or distribution, or the indirect effect of increased
water stress or wind damage which will increase the susceptibility
of trees to attack. Climate change alter the disturbance dynamics
of native forest insect pests and pathogens, as well as facilitating
the establishment and spread of non-indigenous species .
Pathogens can take advantage of changing climate; it could have
major effects on tree health and survivorship .
Forest pathogens may be viral, bacterial or fungal, viral or
bacterial infection and transmission rates seem to vary with
temperature and moisture in the forest ecosystem. Pathogens
like fungal can survive and remain infective over a wide range
of temperatures. However, the conditions that favor epidemic
growth for most fungal pathogens are constrained to within a
band of a few degrees Celsius.
Incident of pests and disease
Climate change increased the extent of greater insect
overwinter survival, shortened reproduction cycles and
development . Insects and pathogens have been noted to
respond to warming in all the expected ways, from changes in
phenology and distribution to influencing community dynamics
and composition . Incidence of pests and diseases may increase
with climate variability and climate change. With long dry spells
and more intense rainfall, the resulting decline in water quality
will lead to greater risk of waterborne diseases . Invasive
forest plants, insects and pathogens can directly cause tree
mortality. Increased disturbance in forests was occurred from
insects, especially from bark beetles. Trees damaged by insects and pathogens can have substantial socioeconomic effects
because of their high physiological sensitivity to climate, short
generation times, high mobility, and explosive reproductive
Many pests and pathogens will reproduce more quickly,
expand their ranges and invade new regions under warmer,
wetter, or carbon dioxide enriched conditions. Insect pests
are sensitive to a warming climate under greater moisture or
temperatures stress their survival and reproductive rate. Climate
change cause tree pest and pathogen outbreak that can have
negative economic and environmental impacts . A highly
virulent pest can lead to significant changes in forest structure
and species composition especially decimate populations of
susceptible tree species .
Trees require light, heat carbon dioxide and water nutrient
to grow through the process of photosynthesis. Increasing
temperature, atmospheric carbon dioxide concentrations
are altering photosynthesis rates and growth. Naturally
plants have their own mechanism to tolerate a certain level
of increased temperature. Soil decomposition rate of organic
matter will increase as temperature increase and then nutrient
mineralization and availability for plants uptake become
increased. Thus, the interaction and different combination
effect of rise carbon dioxide concentration and temperature
is determined by soil properties, water, mineral and nutrient
The availability of forest resources will determine whether a
tree will grow well or not, altering the balance between growth
and mortality and therefore determining forest productivity .
Increase temperature, precipitation, and carbon dioxide alter
carbon balance over longer time and affect nutrient cycling
directly or indirectly through its impacts on forest composition,
growing season length, and the water cycle .
Changes in nutrient availability
Increasing temperature is likely to affect nutrient
availability in the soil through the stimulation of organic matter
decomposition and mineralization of soil nutrients. There are
important links between trees and soil nutrient availability.
The cycling of nutrients between the soil and plants is one of
the main factors of forest ecosystem functioning. Climate change
affect availability of nutrients for plant uptake and limit the
productivity, survival of forest ecosystems. Nutrient availability
affects forest ecosystem and net primary productivity . On
the forest floor organic matter that broken down by microbes
such as down fallen leaves release nitrogen to the soil.
Increasing the nitrogen demand is essential for plant the
growth, development and builds protein however, increasing
carbon dioxide levels in the atmosphere more microbes
are becoming nitrogen limited and releasing less nutrients
to the trees. The productivity of forest ecosystem appears
to be controlled by quantity and availability of nutrient.
Warming temperature has direct physiological effects on rate
photosynthesis, macronutrient concentration in soils and leaves
of tree, shrubs and herbs. Increase in temperature can lead to
reductions in nutrient availability .
Climate change is one of the world’s greatest challenges.
At present global climate change shows a general increase in
temperatures and levels of atmospheric carbon dioxide as well
as changes in precipitation. It creates effects on forest ecosystem.
Climate change affect ecosystem service comprises both goods,
process and it poses major new challenges to forest ecosystem.
Forest ecosystems are sensitive to climate thus; climate change
has significant effects on species distributions, the growth
rate and structure of forests. This paper reviewed research
progresses about climate change effect on forest ecosystem.
The changes in the climate are likely to strongly affect forest
ecosystems by altering the growth, mortality and reproduction
of trees. Forest ecosystems are sensitive and subjected to climate
change produce detectable effects on tree and sapling growth in
natural forests. Climate change particularly facilitates drought,
fire and insect disturbance; thus, changes increase carbon
dioxide concentration, reduce the strength of carbon sinks and
may turn carbon sink into source. Forest fires directly a loss of
habitat, kill plants and animals in forest ecosystem.
Climate change can create a favorable condition for invasive
species to invade the plant ecosystem. Invasive plants are recent
introductions of nonnative, exotic, or non-indigenous species that
are successfully established or naturalized and spread into new
localized natural habitats to cause economic or environmental
harm. Effect on forest health and forest properties with larger
changes in temperature and precipitation will affect forest
ecosystem more strongly. Forest ecosystem pests and pathogens
are likely to increase either through the direct effect of climate
change on their abundance or distribution or the indirect effect
of increased water stress or wind damage which will increase
the susceptibility of trees to attack. Different literature suggests
that global forest ecosystem disturbance such as invasive
species; insects and pathogens in particular are likely to increase
in a warming world. Increasing temperature is likely to affect
nutrient availability in the soil through the stimulation of organic
matter decomposition and mineralization of soil nutrients.
Actively managing forest ecosystem to improve forest
structure, function, diversify tree species, and increase resilience
to climate change. Community awareness programs on effective
forest conservation, reforestation and afforestation can be used
an effective tool to cope with the increasing effect of climate
change on forest ecosystem. Increasing alternative livelihood
and using forest resource in sustainable way. Information and
tools need to be available to make decisions in solving climate
change effect on forest ecosystem. In order to tackle climate change challenges on forest ecosystem, it is important to provide
capacities and support to the forest sector. There is also a need
for alternative practices to reduce subsequent vulnerability of
forests ecosystem, such as planting genetically tolerant trees
identified through breeding programs. Most of the Literatures
discussed only the effect of climate change on forest and
related ecosystem rather than discussing the solution for so, it’s
important to put the solution and action to solve the problem
rather than writing only the effects and constraints.