A "strut zone" is just wherever he feels like dropping and going at it. Seen 'em strutting a mile out in the middle of a mountain pasture.......... in a wooded meadow......... in open timber....... on a state highway........ in a briar and honeysuckle thicket.
Perennial strut zones, like roost trees, are that way because there's features and factors surrounding the area that appeal to gobblers universally. Kill one and the next one down the pecking order will move in.
If you've suddenly got pine groves with 200 yards of visibility under the canopy, you very well could find that area pulling strutters in. Visibility allows the hens to see his display farther and it also helps prevent critters from sneaking up on him. The "features and factors" may suit the birds better than the areas they had been using.