of bedrock running parallel to the coast, forcing groundwater to the surface. In mountain areas the San Gabriel River channel is often too narrow to support significant vegetation, as winter floods tend to scour the channel down to bare rock. Today, most of the streams are locked in artificial channels, and the vast majority of the original wetlands have been lost to urban development. Less than of wetlands remain in the San Gabriel River watershed, with the greatest decline in the coastal floodplain zone. Most remaining wetland habitats are either immediately adjacent to the river, or within the Whittier Narrows and other flood control basins, providing habitat to birds and small mammals. In addition, riparian and wetland restoration projects have been completed or are in progress along the river. The San Gabriel River Wetland Restoration Development intends to construct by 2018 an artificial wetland and bioswale system near El Monte which will provide a recreation area, wildlife habitat and buffer against pollution. Above elevations of , the San Gabriel Mountains support some pine and fir forests, remnants or relicts of a huge evergreen (coniferous) forest that once covered Southern California during the last ice age when the regional climate was much wetter. The montane forests are home to large mammals such as deer and black bears. Due to conservation policies put in place by the 19th century, the upper San Gabriel watershed was never subjected to heavy logging. Also in the San Gabriel River watershed is the San Dimas Experimental Forest, a UNESCO Biosphere Reserve where forest hydrology has been continually studied since 1933. Lower down in the foothill zones, chaparral and brush dominate. The Puente Hills which bisect the lower San Gabriel watershed contain some sensitive plant communities such as coastal sage scrub and walnut forests. Wildfires are a natural part of plant communities in the San Gabriel River watershed. However, after the flood of 1938 an intense program of wildfire suppression began, since burned areas tend to erode quickly during storms, causing landslides and mudflows down tributary canyons. Like many other areas of the western United States this has caused a large amount of tinder and debris to accumulate, increasing the risk of fire. Drought conditions in the first decade of the 21st century led to huge fires much larger than would have occurred naturally. In 2002 the Curve Fire burned , much of it in the North