There are four mysteries here:
1) Where in tarnation is sparc?
2) What were the pallets used for that caused them to be brought to the fields?
3) Why are the pallets still in the field?
4) Why are the pallets not seen during the growing season?
My current conjectures:
1) Sparc is MIA--and the possibility of DT's cannot be ruled out without further information. I suggest someone from NJ attend the local AA meetings in hopes of a sparc sighting.
2) The pallets were used to transport cable spools. (See below.)
3) A break down in the local pallet mafia leadership caused a failure to collect the pallets as promised. There were broken legs.
4) From Sparc's roadside viewpoint, the pallets are obscured by vegetation during the growing season: the pallets are always present but not always visible.
2) Addendum
Numerous long straight lines of pallets stretching great distances across several farms indicate a long, straight construction of something. Returning to the wisdom of the ancients, Ptolemy (AD 90 - AD 168), widely credited with originating the KISS principle, had this advice on theories: "We consider it a good principle to explain the phenomena by the simplest hypothesis possible."
The most obvious, simple conclusion is that
a new EnergyStar rated ELF or ULF antenna was installed in the earth of New Jersey. The supposed politically motivated closing of the GW Bridge was a clever cover-up needed to disguise the work to incorporate the bridge structure into the antenna array to achieve electrical lengthening.
The static generated by tires crossing the bridge deck reduced the power requirements needed by older ELF arrays. As strange as it may seem, DARPA actually received a 30% federal tax credit for the development of the "green" antenna array.
Extremely low frequency - Wikipedia, the free encyclopedia
Because of this huge size requirement, to transmit internationally using ELF frequencies, the Earth itself forms a significant part of the antenna, and extremely long leads are necessary into the ground. Various means, such as electrical lengthening, are taken to construct practical radio stations with smaller sizes.
The US maintained two sites, in the Chequamegon-Nicolet National Forest, Wisconsin and the Escanaba River State Forest, Michigan (originally named Project Sanguine, then downsized and rechristened Project ELF prior to construction), until they were dismantled, beginning in late September 2004. Both sites used long power lines, so-called ground dipoles, as leads. These leads were in multiple strands ranging from 22.5 to 45 kilometres (14.0 to 28 mi) long. Because of the inefficiency of this method, considerable amounts of electrical power were required to operate the system.