SOCIAL AND HEALTH BENEFITS

Transcription

1 1. Why do communities make a special effort to conserve trees? The reasons to conserve trees are numerous. Trees and forests evoke emotions that cannot be quantified. They form biological communities that benefit us now and will add to the quality of life for future generations of plants, animals and people. Along with these emotional and ecological benefits, trees offer economic value to our communities. Farm fields, hedgerows, and woodlands have historically been an integral part of the Hunterdon County landscape, contributing greatly to the visual character and quality of life here. Their disappearance after land development activity is increasingly alarming. One way to understand the problem is to look at how the amount of forest cover has changed over time in Hunterdon County. This information can also be used to measure the success of our conservation efforts in the future. The measure of forest cover loss is relative. Compared to 200 years ago, there is more forest cover in Hunterdon County now. But more recent forest loss and fragmentation trends in Hunterdon County reveal that there was a 20.4 percent decline in the acreage of upland forests between 1972 and Momentum to conserve trees and woodlands is growing in response to the continued loss of wooded acres in recent decades. The high value of trees and the degradation resulting from their removal is bringing communities together to address the problem. We have all heard about the benefits that trees provide. If you ever begin to doubt that the benefits are very real, visit the arid southwest for a while. The difference between living in a place where the natural land cover is forest and where it is not, is astounding. The landscape seems harder, noise levels are higher, and there is little relief from the unrelenting heat and glare. We must not take our forests for granted by assuming that there will always be enough trees to provide the social, ecological, and economic benefits that we now enjoy. SOCIAL AND HEALTH BENEFITS One of the most basic benefits of trees is that they use carbon dioxide and produce oxygen during photosynthesis. As it happens, humans use oxygen and produce carbon dioxide as a byproduct. It seems natural that we would want to conserve trees that produce a key element in the very air we breathe. One acre of trees will generate enough oxygen in a day to support 18 people. As the world s population continues to increase, it also makes sense that we will need more trees to produce more oxygen on a global scale. 1

2 PHOTOSYNTHESIS carbon dioxide + water + light => sugar + water + oxygen CHANGE IN ACRES OF UPLAND FOREST COVER IN HUNTERDON COUNTY: FOREST LOSS IN HUNTERDON COUNTY FROM 1972 TO In 1972 there were 115,586 acres of upland forest cover In 1984 there were 94,441 acres of upland forest cover In 1995 there were 92,018 acres of upland forest cover

3 Firm data on the amount of carbon dioxide trees remove from the atmosphere has recently been gathered. Trees remove carbon dioxide from the air, store the carbon in their trunks, and release the oxygen from the carbon dioxide back into the atmosphere. A large tree, over 39 inches measured at 4.5 feet above the ground, can remove about pounds of carbon per year. Each pound of carbon removed represents 3.67 pounds of carbon dioxide. The same large tree can store 2.6 metric tons (1, pounds = 1 metric ton) of carbon in its trunk. Large trees can store more carbon than small trees, so they have more value for this purpose. A recent study of the effect of trees on air quality was recently completed in New Jersey by the New Jersey Forest Service using the Urban Forest Effects (UFORE) model. The model uses a Statistical Analysis Software (SAS) application along with data from field studies to provide information about how much carbon dioxide urban trees remove from the air. The results of the study show that for just one community, carbon storage by urban trees is thousands of tons. In Jersey City, the tree cover is only 11.5%. The net annual carbon stored is 640 tons. Based on this figure, over 2,348 tons of carbon dioxide and 46 tons of pollution are removed from the air in Jersey City every year by 136,040 trees. Clearly, an increase in the street tree population would improve air quality. Freehold Borough has a total tree cover of 34.4%, which stores a net of 349 tons of carbon every year. This accounts for over 1,280 tons of carbon dioxide and 19.8 tons of air pollution removed from Freeholds air by 47,745 trees. The study produced similar findings for Woodbridge Township and Moorestown Township. Increasing the total number of trees in our communities improves the quality of the air we breathe and may directly help slow global warming. Trees not only produce oxygen, but they also clean the air we breathe. They do this by intercepting and slowing pollutant particles, causing them to fall out of the air, and by absorbing polluting gases. Some of the common pollutants trees reduce are: nitrogen oxides, sulfur dioxides, carbon monoxide, carbon dioxide, ozone, and small-sized particulates (less than 10 microns). In one urban park about 523 acres in size, the existing tree cover was found to remove 48 pounds (lbs) of particulates, 9 lbs of nitrogen 3 The recently discovered problem of global warming and resulting climate change presents us with a new set of challenges. Scientists are not yet able to predict how climate change will affect us. Without clear models, recommendations for offsetting climate change are generalized. The reduction or elimination of greenhouse gas emissions is one solution being widely proposed. Greenhouse gases include carbon dioxide used by trees during photosynthesis. Thus, conserving trees may be one of the easiest things we can do to reduce greenhouse gas emissions.

4 dioxide, 6 lbs of sulfur dioxide, and 1/2 lbs of carbon monoxide every day. One tree 18 to 21 inches in size measured at 4.5 feet above the ground can remove 2.2 pounds of pollution per year. While it is true that trees produce pollen and that mold spores are part of the ecological system in treed areas, trees also remove large amount of these particulates from the air. Studies by NASA have shown that indoor plants can improve indoor air quality. Another set of basic benefits is based on human comfort. Trees provide shade to cool us during the hot summer months, and they block the cold northwest winds during the winter months. In fact, trees can lower the temperature of a paved surface in the full summer sun by 35 degrees F. In our urban centers, we tend to produce heat islands, which are places where the temperature may be up to 10 degrees F warmer than the surrounding countryside. Heat islands are caused by a decrease in wind velocity, heat absorption of paved surfaces, and heat generated from human associated activities. Trees can be used to lower the temperature during the summer months in our heat islands. Evergreen trees that block winter winds can reduce the "chill factor portion of the outdoor temperature and cut down cold air infiltration in the home, resulting in energy cost savings. Trees can also buffer unpleasant noises. Trees can reduce noise by 7 decibels per 100 feet of forest by reflecting and absorbing sound energy. As a comparison, a solid wall can decrease sound by 15 decibels. This benefit becomes immediately apparent when visiting places where there are few trees. You may not see anyone around you, but you can hear them for miles. Trees also provide health benefits by improving water quality. As we develop our communities, we increase the overall amount of paved surface like roads and building roof tops. During rainstorms, water runs off these hard surfaces at a very fast rate. It also carries pollution such as oil and grit from streets, chemicals from lawns, and heat from these impervious surfaces to our streams and ground water sources. Trees and forests act as a filter, removing non-point source pollution like oil, grit, and fertilizers. Forests can remove up to 47 percent of surface pollutants in the first 15 minutes of a storm. Trees also directly shade streams, making them more habitable for trout. As storm water flows from paved areas downhill toward the nearest stream, it may scour the landscape causing soil erosion because it is moving too fast. Fast moving storm water causes undercutting and instability on unforested steeply sloping hillsides. Forested areas trap and hold water for a relatively long period of time. This slows the water down, reducing soil erosion and flooding, and allows pollutants to settle out of the water, resulting in cleaner water entering the stream and groundwater system. It has 4 Conservation is a state of harmony between men and land. -Aldo Leopold

5 been determined that up to 37,500 tons of sediment per square mile washes off developing and developed landscapes per year. Tree covered areas can reduce this amount by 95 percent. Trees also provide many social benefits by providing land use screening, recreational opportunities, beauty, and economic returns. One very common use for trees, hedgerows, and woodlands is to screen undesirable views and to frame high quality views. Trees have traditionally been used to define property boundaries and to separate incompatible land uses, particularly in rural areas. In more rural areas, woodlands provide us with recreational opportunities such as bird watching, hiking, and hunting. EXISTING HEDGEROWS SERVE AS EFFECTIVE LAND USE BUFFERS 5 In fact, storm water run-off can be reduced by about 2 percent for every 5 percent of tree cover area added to a community. Tree canopies have been shown to reduce storm water volume by 7 percent during a six-hour storm. One medium-sized city experienced a 17 percent (11.3 million gallons of storm water) reduction in the volume of storm water run-off during a twelve-hour storm. Therefore, trees also reduce stormwater management costs.