Urban Warming Slows Tree Growth and Photosynthesis
Abstract
This research discusses urban warming describing how it slows down the growth of trees. The research shows that urban warming not only directly impact on growth of trees but affects indirectly as well. Urban warming is caused by a number of factors mainly from depletion of the ozone caused by anthropogenic and natural activities. Anthropogenic activities such as burning fossils fuels contribute much towards global warming especially in the cities which are congested and thus much heat is retained there. Urban warming has increased the rate of pests that attack trees. Pests that attack trees have continued increasing and they are resistant to drugs since the weather conditions have allowed their growth and increased chances of their multiplication and continued survival. As the paper concludes, it is learnt that trees have purposes and should therefore be conserved.
Introduction
From the research carried out urban warming has been seen to reduce the rate of growth in trees and the ability of trees up taking carbon dioxide from the atmosphere. Insects are part of the problem of slow tree growth but heat too has been researched to be a contributing factor. Urban warming is as a result of global warming that has been brought about by peoples interfering in the ozone layer. Ozone layer depletion has caused global warming which is intensified in cities which are much congested compared to rural areas which are rather forested thus less heat exist there. Urban warming is mainly caused by anthropogenic activities for example burning of fossil fuels which can be reduced but people continue to increase them thus depleting the ozone more and ensuring warming is possible. This warming not only affects the cities but aquatic environments as well since the warm water affect the aquatic species and do not support their growth. Therefore urban warming has been a major problem currently since it is a global problem and thus has affected the cities more since cities are congested and lack vegetation cover. Vegetation cover is important in ensuring that people get fresh air since carbon dioxide is absorbed by the plants especially from the industries found in cities. Therefore this paper will focus on discussing how urban warming leads to slow growth in trees and reduces the rate of photosynthesis.
Cities are over 7 degrees warmer compared to rural areas and this condition is known as heat island effect which is caused by global warming. Thus urban warming increases the chances of survival of plant eating insects which feed on trees and cause harm to them and in turn slow their growth. The warm climatic conditions favor survival of these pests that cause harm to the trees from the research carried out by students from North Carolina State University (Meike et al, 1). As the global temperature increase, different types of pests evolve which are favored by the temperatures and thus end up eating the trees and reducing chances of trees growth. This has been a concern since trees are important in the urban areas as they act as carbon sinks. This means that trees are the main carbon dioxide absorbers in cities since the rate of carbon dioxide generation is much because of the congested vehicles, people and industries. Carbon dioxide reduces growth of trees by 12% indicating that it is harmful to the plants. Burning of fossil fuels in cities is in large quantities because the numbers of vehicles increases each day since people have refused going green and prefer vehicles that consume carbon fuels (Meike et al, 1). The industries are many in cities that emit carbon dioxide and other gases which is unfortunate since the levels of carbon dioxide increases which in turn lead to global warming therefore causing the heat island effect. As a result of the heat island effect, pests are able to survive which reduce the chances of survival for trees which are needed much in the cities where carbon dioxide levels are on the increase each day.
The pests or insects that eat trees ensure they suck off all the nutrients from the tree thus trees cannot survive. Such pests are herbivores and include the pine processionary moth and the pine beetles that feed on tree nutrients for survival (Watts & Robert, 77). They suck all the energy thus ensuring the tree cannot grow further and eventually cause death to the trees which are of importance to the city atmosphere. For example growth of the gloomy scales indicates presence of the pests which will take in all the tree nutrients and eventually result to death of the tree which would have helped in cleaning the city polluted air. Thus pests prefer warmer areas since warmer areas increase chances of their survival and reproduction rates (Meike et al, 1). Thus increase in the global temperature will cause more pests and in turn result to reduced number of trees in our cities which is an environmental problem since trees are ecologically important. In cooler areas from the experiments and research carried out, the rate of chances of pests’ survival is low compared to warmer areas. 200 pests are seen to survive in warmer areas more compared to cooler areas therefore indicating that the heat island effect is the major contributing factor to survival of pests in cities which in turn kill the trees (Stinziano et al, 426). Pests are the biggest threat to growth of city trees since they suck all the nutrients and energy from the trees and causing death to the most valuable trees. In order to solve this problem, the environment should be conserved thus reducing the high rates of global warming which in turn reduces the chances of the heat island effect. Pests should not kill the most beautiful trees in the cities and thus scientists should come up with solutions which will ensure the trees are safe from the pests regardless of the climatic conditions found in cities.
Another effect of urban warming on growth of trees is the fact that the warmer temperatures reduces the chances of some trees getting water and other nutrients from the roots and transport them to the other parts of the plants for example the leaves (Teskeyet al, 1670). Trees need water for them to survive and when these two are absent the trees will die. Thus people should plant more trees in the cities, water them till they mature and ensure they survive in order to deal with the problem of heat island effect which has contributed to the increased species of pests that kill the trees. Trees which are infected with pests and those infected with pests look different since the infected ones have less branches. From the research carried out trees in hotter areas infected with pests or non infected have less trunks that trees in cooler areas which have thicker trunks and thus has high biomass. Strong trees have thick trunks which indicate they are healthy and thus urban warming causes reduced trunks in trees and in turn reduced biomass thus trees remain unhealthy (Dawes, 2006). Pests’ invasion in trees is the major problem brought about by urban warming but the temperatures too reduce the trunks of trees even if they are not infested by the pests. This indicates that urban warming is harmful to the growth of trees since it reduces the chances of trees to intake carbon dioxide thus reducing chances of their survival and growth. Due to increased human activities such as burning fossil fuels, the rate of carbon dioxide in tree growth will continue being down thus causing growth of trees with less carbon and more pests.
Trees are very important in the atmosphere as they act as carbon sinks thus cleaning the air by absorbing carbon dioxide, provides habitats to both animals and plants, provide shade and mostly prevent global warming through filtering the air and causing precipitation during evapotranspiration. Trees during photosynthesis take in carbon dioxide thus reducing the concentration of unwanted carbon dioxide which is a major green house gas that causes carbon dioxide. Mature trees are rather not affected by the issue of urban warming unlike the immature trees which are killed by the pests that invade them (Marzluff & John, 258). Photosynthesis is reduced by global warming which in turn reduce the numbers of trees in the cities where trees are needed so that they can filter the polluted air. Water is needed during growth of trees and thus luck of water as a result of warming indicates reduced chances of survival of the immature trees since they cannot survive without water. Thus urban warming reduces the chances of trees getting enough water which will lead to their growth until they mature. Trees in the cities are faced by challenges since pests invade them unlike those trees in cooler areas that pest species find unsuitable for laying eggs and surviving. The pest species in urban areas are unique and are not found in rural areas since they prefer warmer conditions for their survival and growth.
Trees are important since they have an aesthetic value thus ensure the cities look green and beautiful. Infested trees with pests are not beautiful and thus scientists and researchers should come up with drugs that ensure trees survive regardless of the climatic conditions (Costello et al, 67). These drugs should ensure the eggs of the herbivorous pest species die in order to reduce chances of their survival since they lay many eggs and end up multiplying thereby endangering the tree species. The drug should ensure the trees are safe and it should be environmentally friendly in order to avoid other environmental problem that could lead to outbreak of other pest species. They should also come up with pest resistant trees that will endure the harsh climatic conditions in the cities and by doing this they will save the trees which are important and have an ecological value. Urban planners should ensure they research well before planting tree species in the cities since planting the trees that only survive well under cool conditions will only reduce the survival chances of those trees (Falkner & Robert, 120). Trees that do well in warm areas should be planted in the cities since cities are warm thus the climatic conditions will support growth of the tree species. Urban warming which is mainly caused by inexistence of urban forests should be prevented through growth of lots of vegetation cover and trees. Vegetation cover and trees through evepotranspiration contribute to precipitation and thus enough water will be provided for growth of the vegetation and the warmer cities will become cooler. Reducing the rate of carbon fuels will greatly reduce chances of global warming. Reducing the rate of industries and congestion in the cities will reduce amount of carbon dioxide and other green house gases produced thus preventing warming and in turn reducing the rate of heat island effect. Trees are important and should be prevented from being invaded by the species so that they can be useful to the cities.
Conclusion
Urban warming is a threat to our city trees since it only contribute negatively towards their growth and survival. Trees from warmer areas from the research have less chances of survival compared to trees from the cooler parts of the world. Thus urban warming increases the chances of survival of plant eating insects which feed on trees and cause harm to them and in turn slow their growth. Growth of trees in the cities is hindered by some reasons such as lack of enough water to support the growth of trees, reduced rates of photosynthesis in trees and increased survival of herbivorous pests that feed on the trees thus slowing their growth. Trees have ecological importance since they are habitats to different wildlife, filter polluted air and act as carbon sinks and without them especially in the cities the rates of carbon dioxide will increase and in turn more heat and unwanted carbon dioxide retained. Thus the problem of urban warming should be solved in order to ensure that trees grow and mature in the warmer areas without the problem of heat island effect as one of the hindrances.
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