A pressurized-sounding wind seen moving slowly about a Wildlife Preserve without any visible craft above its effects.Greetings- I have never been a skeptic after witnessing an orange/red glowing orb in upstate NY as a teenager which resulted in a time lapse to my knowledge but was never discussed afterward amongst the two people in my company.The following event occurred today: As an avid hiker, I was resting on a trail which I enjoy trekking every week for about 5 months now. The trail itself is roughly two hours long. I was about half an hour into the hike. The trail head is not near any main thoroughfare and the number of cars at the trailhead today was minimal so there were few people on trail.Let me describe the area; The trail area was a wishbone-shaped terrain. The main trail was singular before breaking into two parts. I was resting at the lower "part". On each opposing side the terrain grew gradually on the opposing sides into simple enbankments rising somewhat quickly. Opposite to me was not a rocky terrain but was mostly low-level scrub brush and the local spruce reaching no more than 10-12 feet in this specific area.As I rested I began hearing what sounded like a wind in the distance. It immediately registered to me as a moving vehicle before I realized I was miles from any road. The sound was first heard moving from my right out of sight up the trail from where I had just traveled. As I realized there was no way it could be a vehicle I tried to register what in the world it was. I kept watching the trail bend where I heard the sound approaching and wondering what in the world it was.The wind here in Oklahoma is different- it can gust quite differently than most places. I've lived after having been active-duty in the Air Force for 10 years abroad and having live in upstate NY near Lake George and south of Lake Placid growing up. This wind was unlike anything I've heard or seen.It was moving up the path still out of my line of sight. When the sound came into view I knew it was something but I saw nothing. I saw no object or any craft but "it" continued to emit a strange sound like a "hollow wind" but there was no object. It began deviating slowly away from the trail up the embankment and I watched its effects. It was moving quite slowly and deliberately and it made my hair stand up to watch it.I knew it wasn't the wind but there wasn't any object or anything. As it moved slowly enough for me to watch it the effects area of its entire motion was about 20-25 feet in length- meaning, the area which was affected by this movement of air was a 20-25 foot space of land/shrubbery/dirt underneath which was continully being moved as it moved slowly forward or more accurately to my left at about 50-75 yards in front of me.I was quite mezmorized knowing wind doesn't make that sound or travel that slow or deliberate while remaining as though contained in the same specific area.As it moved into almost my direct sight at approx. 50-75 yards away, I muttered "what is that"? At that point it slowed and stopped in place but continued moving things about underneath it but in place with an approx. width of about 20-25 feet. I was still dumbfounded as I continually looked above it and saw nothing but watched its effects beneath.At this point my instinct fight/flight was taking over but as "it" remained still, I was better able to hear the sound more clearly and it sounded more like escaping pressurized air. Also at this time I noticed clear evidence that this was nothing ordinary because the branches of the small spruce trees underneath were moving vertically up and down and NOT horizontally as they would have with any normal wind.Ater "it" remained in place for about 4-5 seconds there is no question I could not see anything above it. I did feel like I was looking at something though because I let my eyes scan freely and they locked on about 30 feet above the spot.However- the sound slowly stopped, not immediately but it faded and was gone. That was it. No further sound- no nothing. After reading some about sightings I've read there is often radiation found in the vicinity so I was not eager to inspect the area but to perfectly honest I just wanted to leave the area quickly.