Density and Yield
The standard orchard density is a 6 × 6 meters.
One way to get profitable returns from a hazelnut orchard much earlier than usual, while avoiding the usual drawbacks of intercropping (planting another crop between the tree rows), is to plant a high-density orchard. Because the yield per tree from a high-density orchard is nearly the same as that from a standard-density orchard for the first 5 or 6 years, yield per hectare goes up in proportion to the increased number of trees. Thus, in a double-density orchard, per-acre early yield is double that of a standard orchard.
Rectangular spacing of 3 × 6 meter with 538 trees per hectare or 3.6 × 5.5 meters with 496 trees per hectare allows for thinning to a triangle of approximately 6, 6.4, or 6.7 meters, which makes cross-flailing (flailing in two directions) easy. An herbicide-treated strip of soil down the rows reduces the need for cross-flailing, but cross-flailing helps eliminate grooves in the soil surface, which makes harvest easier.
Table 1 shows theoretical yields from 3 × 6 meter spacing versus a standard 6 × 6-meter planting. When the trees become crowded, some growers prune back the temporary trees to allow the permanent trees to grow out in a fairly normal pattern. The temporary trees are removed after year 10.
Spacing and Arrangement of Permanent Trees
The standard 6 × 6 meters with 267 trees per hectare is adaptable to a variety of soils and situations. The advantage of this slightly wider permanent spacing is that it provides a good, productive environment that has plenty of sunlight. A disadvantage, compared with closer spacing, is lower early yield. Figure 1 shows an orchard layout with 10% pollinizers placed every third tree in every third row.
For well-managed orchards with good soils, an 5.5 × 5.5 meters square with 331 trees per hectare is a good permanent spacing for some soils and varieties. It accommodates standard-size equipment and makes it possible to work the orchard in three directions. This helps avoid grooves in the soil surface, which may form when the orchard always is worked in a single direction. The main disadvantage is that it is difficult to interplant other crops between the rows because of the reduced alley width between trees.
A 3 × 5.5 with 598 trees per hectare can be thinned to form a 6 × 6.3 meters by removing every other tree. The main advantage of this arrangement is early yield. Disadvantages include the inability to cross-flail, higher costs to purchase and maintain additional trees, and the cost of tree removal at thinning time. Use this arrangement only if you are willing to provide intensive management.
Head Lands and Loading Zones
It is important to leave enough room at the edges of the orchard to comfortably turn a tractor and sprayer or harvester. You need to leave enough room to turn into the next row without stopping and backing up. Also leave some open area where you can stack tote bins during harvest. Placing the loading area near a road will reduce the time needed to fill a truck for delivery to the receiving station.