Canopy Management

1. Maintain health of tree:

• Remove all dead, dying and diseased limbs
• Remove crossovers, which can rub together and damage limbs and harbor disease
• Remove hazardous branches before they fall
• Correct and repair damage

2. Raise the canopy to enable passage of machinery (sweepers/harvesters) through the orchard

3. Rejuvenate the tree by removal of old wood in such a way that encourages the formation of new wood (remove no more than 1/3 of the wood in one year)

4. Improve the aesthetic quality of the tree and thus its value

5. Slow the tree's growth by timely removal of foliage

6. Maintain nut production

• Remove limbs that grow down or straight up
• Maintain tree size
• Develop strong 45 degree angles to support nuts

The best time to prune trees is generally during the dormant period, usually in late winter (November–March). However pruning can be done year-round, as needed; for example, dead or diseased branches can be removed any time, the sooner the better.

When pruning trees keep this in mind: Pruning done during the dormant season tends to have an invigorating effect on tree growth. Pruning done during peak growth times tends to slow growth by removing leaves that manufacture nourishment, but too much summer pruning can damage a tree. Pruning during the spring (post-dormancy) and fall (pre-dormancy) is generally the least desirable time as the plant is most vulnerable during those times.

Sooner rather than later: When you cut away part of a plant, a wound is left, susceptible to pests and diseases. To avoid trouble always prune so as to make small wounds, rather than large ones.

Removing a bud or twig produces a smaller wound than waiting until it is a large limb! Rubbing off a sucker bud leaves a smaller wound than if you wait until it has a year's growth or more.

The best time to prune trees is generally during the dormant period, usually in late winter (November–March). However pruning can be done year-round, as needed; for example, dead or diseased branches can be removed any time, the sooner the better.When pruning trees keep this in mind: Pruning done during the dormant season tends to have an invigorating effect on tree growth. Pruning done during peak growth times tends to slow growth by removing leaves that manufacture nourishment, but too much summer pruning can damage a tree. Pruning during the spring (post-dormancy) and fall (pre-dormancy) is generally the least desirable time as the plant is most vulnerable during those times. Sooner rather than later: When you cut away part of a plant, a wound is left, susceptible to pests and diseases. To avoid trouble always prune so as to make small wounds, rather than large ones. Removing a bud or twig produces a smaller wound than waiting until it is a large limb! Rubbing off a sucker bud leaves a smaller wound than if you wait until it has a year's growth or more.

When pruning, be aware that hazelnuts are very susceptible to wood rot fungi. This means that the larger the size of the cut made, the higher the chances are for infection. To prevent this, keep the branch collar (the raised area at the base of each branch) intact while making the cut, as it contains specialized cells which seal off a pruning wood naturally. In coastal areas, be sure to slope cuts slightly so that water runs off when it rains. Generally, cutting straight across to limit the size of the open wound is a good practice. If cuts are greater than 2.5 cm in diameter, protect them from exposure by application of a pruning cover (spray on or paint on).

Heading (topping)

 Heading is the process of cutting the tops of tall trees to a desired height, either angled or horizontally. Cutting a portion of a branch off tends to cause a flush of multiple shoots to grow below the cut. Oftentimes this regrowth is not productive- making too many heading cuts causes the growth of excessive outside foliage, which limits the tree’s light exposure.

Thinning

Removing whole branches often improves light penetration, which is necessary for flower and eventually nut set.  In mature trees, most cuts should be thinning type cuts.  Make the cut to a lateral branch as this helps redirect the regrowth and making a healthy pruning cut.

• Oregon Hazelnuts
• OSU Basic Pruning Guide

In overgrown orchards, cutting off about 10-15 feet in height may be necessary.  Remember to cut lateral branches that are within the range of height that should be achieved. Branches should be cut at varying heights to prevent flat tops.  Over all, the goal in a rotational pruning program is to reduce the fruiting wood by half on the trees.  This goal can be achieved through height reduction cuts and proper management.

• Oregon Hazelnuts