Windbreaks: Maintaining the Health, Productivity and Longevity of Your Trees

Key Maintenance Practices

Healthy, productive windbreaks require maintenance to help prolong their life and effectiveness. There are several essential maintenance practices:

planted windbreak.

Farmers appreciate windbreaks for more than crop and soil protection:

"Before [the windbreak] was planted here, it was nothing to have four or five feet of snow up through the driveway - and this year with all the snow we had, we had a maximum of ten inches of snow. I'm thrilled with it. It's done everything it's supposed to do and probably more."
- Mike Downey
- Alma, Wellington County

Watering and Refill Planting

In the first year of tree growth, watering and refill planting are necessary to establish an effective windbreak.

Watering the windbreak in the first year is critical because the trees are establishing new roots. Second and third year watering should still be considered, especially during really dry summers. After the third year, the root system should be developed enough to support the tree in drought conditions.

John Enright, a forester with the Upper Thames River Conservation Authority, maintains that it is important to assess the amount of tree growth and survival rate a year after the windbreak is planted. Assessing the tree survival rate can help farmers decide if refill planting is needed. Leaving gaps allows excessive winds to pass through the windbreak, which can damage crops and erode soil. Refill planting will bring the density of the windbreak back to 100 per cent by filling any gaps left by dead trees from the first growing season.

Vegetation Control and Mowing

Planting windbreaks into ground covers (e.g. winter wheat under seeded to Dutch white clover) reduces maintenance costs and weed pressures in the windbreak area, and makes future mowing easier. Mowing several times a year up to three years after the windbreak is established helps to reduce the amount of weeds that compete for moisture, nutrients and sunlight.

Mowing late in the fall can reduce winter rodent habitat. This is especially important when trying to establish a hardwood windbreak because rodents will remove bark in the winter months, putting the tree's health at risk. Removing easy rodent habitat makes it easier for predators, such as hawks and foxes, to find their prey.

Herbicides can prevent weeds and grass from growing around the trees. Herbicide application is recommended two to three times in the first three years after the windbreak is planted. Farmers can decide if herbicide treatment, including spot or band spraying, is necessary for their trees after the first year of growth. Some conservation authorities offer a windbreak herbicide program. Contact your local Conservation Authority for advice an applying herbicides for vegetation control when establishing windbreaks.

Thinning and Pruning

Thinning after ten years of growth may be necessary to maintain crop and soil protection, or to develop harvestable wood products. Thinning also helps to create a more effective shelter zone on either side of the windbreak, reducing the effects of wind up to 10 times the height of the tree. Mark Funk, the Grand River Conservation Authority's Forestry Specialist, suggests that when windbreaks are thinned, the remaining trees have more resources and room available to grow. Minor gaps created by thinning will usually close within a few years, resulting in stronger and healthier trees.

man pruning a tree.

Pruning is another form of maintenance. Pruning of hardwood windbreaks enhances the structure of the trees and is necessary for the development of future harvestable wood products. It also results in a more effective windbreak. Pruning can provide clearance for farm equipment and improves the longevity of the windbreak.

It is better to prune regularly rather than infrequently. Infrequent pruning places a lot of stress on trees, often resulting in slow growth and windbreak development.

Make a pruning and thinning plan before you cut your trees. Farmer Mike Downey, for example, consulted his local conservation authority on the best way to thin his windbreak. Together, they developed a plan to remove trees from a two-row spruce windbreak in a staggered pattern, which prevents major gaps in the windbreak that would allow a direct path for wind.

man thinning  a windbreak.

Thinning a two-row spruce windbreak by removing trees in a staggered pattern eliminates a direct path for wind through the windbreak.

Windbreak Maintenance Tips

  • During summer drought conditions, watering every two to three weeks is considered adequate for new trees. Over watering can be harmful as it may create shallow root growth.
  • Fertilizers are not recommended for use in a windbreak. The nutrients will be taken up by the weeds and grass, creating growth competition for new trees.
  • Mow the vegetation around the trees for the first three years after a windbreak is planted.
  • A mixture of wheat and white clover are ideal ground covers for around the trees. The wheat grows taller and protects the young trees, and the clover provides great ground cover and moisture retention.
  • Wait a few years after the tree is planted before pruning. Pruning a tree when it is too young can "shock" it.
  • It is easier to make frequent minor pruning cuts, such as yearly, than to make major cuts, such as once a decade.

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