About 35 years ago, Edstrom first set foot in an almond orchard. His Chico-area home sat in a 50-tree-per-acre orchard with towering 50-foot-tall almond trees. The standard tree spacing in those days was 30-by-30 feet.

Today’s high density-planted orchards can include up to four times more trees, Edstrom says. In the Sacramento Valley, spacings of 15-by-22 and 16-by-22 are common today. In prime soils, 18-by-24 and 20-by-24 spacings are preferred.

“High-density plantings fill the canopy faster and yields are dramatically higher in the third, fourth, and fifth year,” Edstrom said. “Years ago we did not harvest third year crops — that’s not the case anymore.”

Soil modifications increase yields. The slip plow and other equipment effectively mix the soil layers to create improved root growth plus better oxygen and water infiltration.

Pruning has evolved from heavy pruning to moderate or minimal pruning depending on the soil type.

These research-developed findings by this researcher trio and others have sparked high yield increases. Yet dense, high-vigor orchards have generated production obstacles including more disease problems (alternaria leaf spot, rust, scab, and hull rot); ceratocystis canker-related shaker damage; and delayed crop maturity and hull drying tied to increased shading and stagnant air.

“Increased disease requires more fungicides and higher costs,” Edstrom said. “I know several growers this last season who applied seven fungicide sprays. If a single spray costs $50 per acre then that’s $350 an acre. That’s more than the cost of bee pollination.”

Mario Viveros moved to Kern County in 1979 when statewide almond acreage totaled about 63,100 acres; about 60,500 bearing. Today, California farmers grow almonds on about 750,000 bearing acres in 16 counties.

Kern is the largest almond-producing county in the state, in order, by Fresno, Stanislaus, and Merced counties. Today, California almond growers produce an 80 percent chunk of world production.

In 1979, Kern County almond yields averaged about 1,400 pounds/acre.

“A good grower was happy with 1,600 pounds,” Viveros said.

Production costs averaged $900 to $1,100 per acre. Frost risk was minimal in most areas and diseases were almost nonexistent. The primary problem was insects.

“The navel orangeworm ate our cake,” Viveros said.