The forests of the New York City Watershed also provide habitat, food, and protection for a variety of wildlife, while moderating stream temperature and oxygen levels to foster fish habitat. Forests cycle nutrients constantly in many different ways to keep the system thriving. Nutrients move from the soil into tree roots, up the tree to its leaves, then are returned to the soil through leaf and twig fall. Soil microorganisms then utilize and process these nutrients back into a usable form for root absorption. Without forested land to complete this cycle, soil nutrients are lost or eroded into the water supply at levels possibly dangerous to humans.
Forests also cycle carbon and oxygen in the atmosphere.
But, put simply, it is the process by which larger contiguous forest lands are broken into smaller, more isolated fragments or islands, surrounded by human-modified environments of agriculture and urban land uses. A concern in the NYC watershed is that the present taxation system applied to forested land in the Catskills creates inequities between towns and counties and is likely to contribute to unfavorable land use changes within the watershed. Landowners may be forced to sell their forestland because they are unable to pay the corresponding property taxes. These sales often result in forest fragmentation. Ten Year Ownership Projection Sixty-one percent of the forest land in the watershed will be privately owned, and as a result is at a greater risk of fragmentation than publicly owned lands.