As early as 1753 settlers noted problems to waterways due to forest clearing.

Forest capacity to intercept rainfall is immense, the canopy alone can intercept 10-40% of rainfall, even deciduous trees in winter intercept 15%. Most forests can absorb 15-20 inches per hour. Evapotranspiration, as trees draw water from soils and releases it into the air, readies soils to absorb the next rainfall. Water is the product of its watershed.

Forest loss peaked in the late 1800’s as farmlands were established. Forests regrew until 1960’s. However there has been a loss of 100 acres of forest a day in the Chesapeake Bay Watershed since the mid 1980’s. The question for us now is: Can we prevent continuing loss of forest to development? The water yield is directly related to forest quality, incremental loss occurs house by house as development creeps across the countryside.

The forest ecosystem is very complex, when converted to houses, the system is so simplified that the loss is immeasurable. The supply of water to aquifers is a constant loss that is showing up in loss of adequate surface holding areas and wells.

With a continuing loss of forest, there is a corresponding nutrient input to the Bay, making water quality goals difficult to achieve. Many trees will never grow to maturity due to a lack of incentive programs for forest management.

Healthy streams can treat 40% of pollutant intake due to their biological life. When streams are deprived of natural forest buffer and are subject to urban point and non-point pollution, it is a larger contributor to stream degradation than agriculture.

Forests are the most beneficial land use for water quality, but there are few programs that target forest protection, rehabilitation, replanting. Tree canopy is useful to reduce urban stormwater runoff, but trees are not integrated into stormwater regulatory framework.

Maryland is only 40% forested, unlike VA which is 57% forested, NY and PA which are 61% forested. By 2030, if current trends continue, we will lose 21% of remaining forests and stormwater runoff will increase by 30%. Communities will spend billions to replace services forests provide free. Stormwater runoff is the #1 problem for urban streams and rivers.

Goetz’ studies of Montgomery County’s 245 watersheds show that with 15% impervious, watershed tree cover reduced to 50% and 60% riparian tree cover, streams were in good condition. Over 75% of urban stormwater does not infiltrate. The most important services of forests, other than stormwater sequestration are, cooling the urban heat island effect, air pollution and ozone reduction, carbon sequestration, improved air quality, energy savings, quality of life, aesthetic and real estate values, neighborhood stability, noise reduction, habitat for birds and other wildlife, People linger longer to shop on tree lined streets. Office space with trees has more productive workers and less absenteeism.

Even in winter, deciduous trees can intercept 15% or rainfall, evergreen, 27%.

We need to preserve priority forests, develop forest goals for each watershed, enhance urban and suburban tree canopy, protect trees and expand plantings on development sites, reduce lawn in favor of trees. Use GIS analyses to predict future stream health and place a value on forest cover.

Establish tree ordinances, neighborhood give-aways, tree vouchers as in Baltimore County. Encourage development to use Environmental Site Design to preserve forest, cluster buildings, narrow streets, shared driveways, include trees in design for stormwater during and after construction, as a public amenity, to increase infiltration in ways that enhance the beauty of the site, increasing, in the process, the value of homes.

Trees are the ultimate multi-tasker. We need cooperation between engineers, landscape architects, planners if we are to succeed in placing a high value on forest retention and replanting.

In the Lake Tahoe region, the League to Save Lake Tahoe sued the state of California and the EPA for non-performance regarding the need to protect the Lake from further degradation from development. The High Court sided with the plaintiff “until a better plan can be developed”, resulting in a three year moratorium on building permits. The Plan that resulted was science based. The Forest Service mapped the areas most sensitive to development, (1% impervious cover) and created a guide for the most impervious surface allowable in the entire basin. When a plan is based on clear science the courts will uphold preservation against private property rights. Three cases challenging the rules were brought before the Supreme Court and all were defeated by the Plan. The Forest Service owns 4-5,000 building lots, purchased as a buy-out for owners who lost their right to develop. The Plan created a huge incentive for redevelopment and restoration, trading credits from other properties.