Out back in the hundred acres of yellow pine crowding close to C. C. Thompson's mobile home, the scattered sprays of blue paint readily stand out on the tall old trees.

The sprays are the hallmark of harvest time, and the crop is timber, wood for the South's resurgent forest industry to convert to plywood, studs and fiber board for the nation's current boom in housing construction.

That construction, nearing the record year of 1973, has squeezed lumber supplies and pushed prices to record levels - bringing complaints from Washington that too many Americans are being priced out of the housing market.

But the demands for lumber also have brought additional prosperity to people like Thompson who sell timber, and to the small cities and tiny towns like those here in east Texas that are so reliant on their woodland industries.

"It's been wonderful," said James M. Vardaman, a private forestry consultant in Jackson, Miss., who helps landowners across the South manage and market their timber. "All of our clients are extra-pleased at these prices."

"The impact is tremendous," Edwin Barron, head of the forest management department of the Texas Forest Service, says of this economic effect on timber communities.

"I gotta use what I got to live on," says landowner Thompson, a 64-year-old retired security chief from the port of Houston who bought his 102-acres in 1947. He declines to say how much he received for his timber, but based on prices quoted here the 205,600 board feet he sold this summer to International Paper Co. should have fetched between $25,000 and $30,000. He and his wife, Adell, do admit to splurging on a new car at the local Buick dealership to give to their daughter in Houston.

The prices paid for timber have never been so high - helping to add $700 and $1,500 to the cost of an average new home, according to Housing and Urban Development Secretary Patricia R. Harris. They have been a particular blessing for the South. For while the region stretching from Virginia to Texas is not the nation's largest timber producer, the bulk of the woodlands, 73 per cent, is held by individual landowners. They may have more acreage or less than Thompson, be local residents or big city investors living hundreds of miles from their holdings, or be landed gentry with large and long-held family tracts.

Multi billion dollar International Paper say it expects to buy 60 per cent of the timber it buys here this year - about 48 million board feet - from such private landowners. The price is expected to range from $90 to $140 for each 1,000 board feet (reflecting an increase of $30 in the past 10 months) for up to $6.7 million in local timber purchases.

"Timber is an important factor, one of our biggest business," notes Nacogdoches mayor and Ferdonia State Bank president A. L. Mangham Jr. Unemployment in the city of 26,000, 137 miles north of Houston, is less than 3 per cent, he says. Bank deposits are rising steadily and two savings and loan firms are operating at capacity, with a third about to open. From 1960 to 1970 Nacogdoches grew 76 per cent, making it the fastest growing non-metropolitan area in Texas.

While Thompson's timber sale was his first, A. Wayne Corley, a 36-year-old certified public accountant in Lufkin, and two partners can attest to what has happened to timber prices in the past years.

In June, 1976, Corley said, they sold one million board feet of timber for $115,000 or $115 per 1,000 board feet; nine months later they sold timber from an 11-acre tract for $160 per 1,000. A board foot is a piece of wood 12 inches by 12 inches by one inch, or an equlvalent volume.

The price of timber is not the only windfall in these east Texas communities and elsewhere in the South. Because of increased cuttings, the demand for private crews to cut and haul timber has driven their fees up. One firm, Temple-Eastex, said logging costs are up some 20 per cent over a year ago, meaning that crews that received $32 to $40 a thousand board feet a year ago now get $35 to $48 as they fell the towering Southern pines, strip them of branches and stack them on huge logging trucks that roar up and down U.S. 59 and a score of lesser roads in this east Texas timber belt.

Lumber mills and plywood plants have also lengthened workers' shifts or added employees. The Temple-Eastex plywood plant in Pineland has added 50 people to its labor force of 500 this year as it brings the five-year-old plant up to full capacity.

"This whole county would be ship-wrecked without us," said John Booker, the plant's manager, of his $4.5 million annual payroll. "This is the tax base for several independent school districts." As he speaks, a growing 8 1/2-foot-wide lathe peels a thin veneer from skinned pine logs, unrolling eight-foot, four-inch-wide ribbons of sweet smelling wood, 30, 40, even 50 feet long, to be sheared treated, bonded and trimmed into plywood.

Until 15 years ago the South's pine trees, the regrowth of woodlands decimated by overcutting in the late 1800s and early 1900s, were considered too small in diameter to be peeled for plywood. Then new technology made it possible to produce plywood from trees as small as 11 inches in diameter.

The result: Today the South produces 35 per cent of the nation's plywood and expects to increase that share. So it may be that Pineland and hundreds of other outlying Southern towns would be wrecked without plywood manufacturing. In many respects, the prosperity of the so-called Sunbelt, with its growing population centers and prospering economies, has extended into the rural communities as well as the big cities.

The timber industry, like most based on agriculture, is subject to downs as well as ups. Thomas Orth, president of the Kirby Lumber Co. in Houston and also president of the National Forest Products Association trade group, notes that between the three good years of 1969, 1973 and 1977 there were bad ones. Indeed, the current demand, says Tom Finch, has allowed his International Paper plywood plant here to get back to full plywood production and full staffing after 50 per cent reductions in the slack years of 1974 and 1975.

Orth and others in the lumber industry say prices - both for trees and finished products - move almost precisely with the number of new houses being built.

Moreover, industry analysts say that this year lumber dealers depleted their stocks and then began almost panic-buying as predictions of a 1977-78 housing boom began. The increased demand drove prices up accordingly.

"There's nothing criminal going on," said a long-time industry expert, "there's something stupid going on."

But already there are signs that prices have peaked and are edging back down. But Orth, citing past patterns, says the prices probably will not go as low as they did before the current rise.

And if the cycle of high prices repeats itself, that will be fine for the C.C.Thompsons. He figures that in about five years he'll be ready to have more trees cut from his land. "It's going to help us do the things we want to do and go the places we want to go," he says. "I just love this place."