CONCORD — The Society for the Protection of New Hampshire Forests announced Monday it has purchase-and-sale agreements with four North Country landowners that could thwart construction of the Northern Pass.

Now its “Trees Not Towers” campaign must raise $2.5 million by Oct. 31 to complete the transactions.

“New Hampshire needs to protect itself from an industrialized corridor that could support multiple transmission lines in the future, regardless of the outcome of the immediate Northern Pass proposal,” said Jane Difley, president and forester of the state's oldest and largest conservation organization.

All four parcels were being sought by the developers of the $1.1 billion project, which is being proposed by Northeast Utilities and Hydro-Quebec.

“They have tried and failed to stop the project,” Martin Murray, spokesman for Northern Pass, said Monday, noting Northern Pass will continue to work with “willing landowners” on acquiring land.

He called the announcement a “convenient fund-raising tool” for the conservation group.

Last December, the society signed a purchase-and-sale agreement for 5,800 acres of the Balsams resort property in Dixville Notch — land also being sought by Northern Pass. Within five weeks, it was able to raise $900,000 to buy the tract.

The proposed high-power transmission line would run 180 miles, using 140 miles of existing right-of-way owned by Public Service of New Hampshire from Groveton to Deerfield. The remaining 40 miles from Groveton to Pittsburg has to be acquired by the project because there is no existing right-of-way.

The society and other opponents are concerned the 1,100 proposed towers — ranging in height from 80 to 135 feet — would destroy the landscape, hurt tourism and reduce property values.

Developers of the project and their supporters contend it would be good for the state, reduce utility costs and add construction jobs.

Officials for Northeast Utilities have told investors it expects to have the proposed route identified by the end of the third quarter, which is Sept. 30. If not, it indicated, it was likely the project would move back from a 2016 on-line production date to 2017.

The Legislature took eminent domain off the table for the project last winter, forcing the developers to work on a willing-seller basis. So far it is estimated the project has spent $15 million acquiring 40 North Country parcels, sometimes paying more than 20 times the assessed value, said Will Abbott, vice president for policy of the Forest Society.

The society is seeking to purchase 1,895 acres in five separate tracts. They include:

-525 acres of North Hill in Stewartstown owned by Green Acre Woodlands.

-The 970-acre McAllaster Farm on Mudget Mountain in Stewartstown.

-Two small parcels owned by Lynne Placey, totaling roughly 100 acres in Stewartstown.

-300 acres in Columbia owned by the Lewis family, which links the southern boundary of the Balsams tract and the boundary of the Nash Stream State Forest.

Asked why the society set an Oct. 31 deadline, Forest Society spokesman Jack Savage said there is “an urgency to stop them now ... there is an imperative to raise enough to protect not only these, but other lands as we move forward.”

Click Here to view a map of the Northern Pass route prepared by the Society for the Protection of NH Forests

Click Here to view another map of the Northern Pass route prepared by the Society for the Protection of NH Forests (closer view)

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