It looks like a tree plantation or heavily managed forest where an area was cleared years ago and replanted with seedlings all of the same age, in rows. This patch of forest will be cut at some time in the future. The forest as a whole is made of many patches of different ages, scheduled to be cut at different times.

The trees have dropped their lower limbs as they grew probably because of competition for light.

A tree that grows taller and puts less energy into maintaining lower limbs will be more successful in such an environment. Foresters plant trees closely enough to cause such growth as it results in straight, tall trunks.

There is a park like look to the scene because of the lack of understory. This is most likely also because of an even lack of light. If there were some dead trees there would be small areas of sunlight with grasses, ferns, small bushes, etc.

The second reason is that the forest floor is covered with moss. This means the area is wet enough of the time to support moss and may not be appropriate for many other plants that you might find in similar light levels. The carpet of pine needles that probably falls may also prevent the growth of some low understory plants.

At least, that's my interpretation of the scene.