Durability

• While trees are a renewable resource and are a good choice for building bridges, the durability of wood is not as high as other materials. Since bridges are exposed to the elements at all times, particularly humidity for bridges over waterways, they can easily rot and deteriorate. The life of a bridge built from wood is significantly lower than one that is build from concrete or metal. This means that wooden bridges require more trees over time.
  
  

Chemicals

• Because wood deteriorates and rots, wood that builders use to make bridges must be treated to protect it from the elements. These chemicals are slowly released into the air during the life of the bridge. This seepage has a negative impact on the air quality around the bridge, as well as the plants and animals in the area. This contamination makes wood bridges less environmentally friendly.
  
  

Production

• The production of a wooden bridge requires fewer and different resources than other bridges. To make a bridge out of concrete, for instance, any waste that builders create in the building process ends up in landfills. With wooden bridges, the waste can be used for other purposes or recycled. The use of concrete also produces more dust and releases more carbon monoxide into the air. A wooden bridge, though, does require some fuel use, such as natural gas and fuel oil.
  
  

Fitting In

• In some instances, it is more visually appealing to create bridges that fit into the environment. Wooden bridges often use woods that are native to the area and look more natural in their surroundings, especially in parks and other natural locations. Since some companies build their bridges from the top down, the process also produces little damage to the environment around the bridge. This makes it the best option, especially when builders want the area to remain as natural as possible.