ALBANY

Stymied from cutting trees along the path of the proposed Constitution natural gas pipeline, its owners Thursday pushed back the start of the line's expected operation at least six months, from the end of 2016 to the second half of 2017.

The company blamed the delay on a "rapidly closing environmental window" to cut trees along the line's planned route in New York, where gas from the hydrofracking fields of northern Pennsyvania would move through the Southern Tier to the Schoharie County town of Wright.

Limits imposed by the Federal Energy Regulatory Commission (FERC) and U.S. Fish and Wildlife Service allow Constitution to cut trees only between Nov. 1 and March 31 in order to protect migratory songbirds and the northern long-eared bat, whose numbers have been decimated by a fungal disease. The bat is listed as threatened under the U.S. Endangered Species Act.

On its route in New York, the pipeline would cross 270 bodies of water and clear 1,000 acres of forest containing 700,000 trees. More than 700 parcels of land are affected by the proposed pipeline, and 120 landowners face losing property to the gas company under eminent domain.

Constitution already has cut trees along about 25 miles of the pipeline's route in Pennsylvania, but has been unable to to start work in New York. The state Department of Environmental Conservation is still considering necessary water quality permits, and without those permits, Constitution cannot legally cut trees.

DEC is expected to decide on the permits by March 31. Last month, Constitution sought permission from FERC to start cutting trees in New York before DEC action on the permits, but that effort was blocked by state Attorney General Eric Schneiderman, as well as environmental groups including Catskill Mountainkeeper, Clean Air Council, Delaware Otsego Audubon Society, Riverkeeper, Sierra Club and Stop The Pipeline.

The planned $750 million pipeline would carry hydrofracked natural gas from Pennsylvania into New York, crossing through Broome, Chenango, Delaware and Schoharie counties to connect with the existing Iroquois gas pipeline in Wright.

Iroquois now carries gas from western Canada southward into New York, the Hudson Valley, Connecticut and Long Island. Last year, Iroquois' owners proposed reversing that flow northward, so gas could flow toward Canada. Once there, another pipeline network through Ontario, Quebec, Maine and New Brunswick leads to Nova Scotia as a path to potential natural gas export facilities.

According to a Constitution statement issued Thursday, the company "anticipates beginning limited mainline construction in the summer of 2016. Full mainline construction would continue after Oct. 1 to minimize and avoid adverse impacts to migratory birds and the Northern Long Eared Bat.

"All activities are subject to third party environmental monitoring. In coordination with state and federal agencies, Constitution Pipeline has agreed to voluntarily provide $8.6 million in conservation funding for the restoration and preservation of migratory bird habitats in New York and Pennsylvania as a conservation measure," according to the release.

The pipeline is a partnership of Houston-based Cabot Oil and Gas Corp; Williams, an Oklahoma-based energy company; Piedmont Natural Gas, and WGL Holdings.