Hedgerows & Windbreaks

Hedgerows & Windbreaks

The Island was once almost entirely forested. As land was cleared for agriculture, the boundary lines between farms had to be fenced to keep livestock from straying. Many times the first fences were roughly-piled stumps and poles (the expression “ugly as a stump fence” comes from that era). Stones laboriously picked from fields were thrown along these lines as well. Internally, farms had to be cross-fenced into fields of a suitable size for crop rotation, and also to keep livestock where they belonged. The result was to turn the land into an attractive and functional checkerboard pattern of inclosures and exclosures.

Traces of this pattern remain today in the living boundaries that we call hedgerows. This Island wants to grow trees, so land not cultivated will soon start to become woody again. Single or double lines of trees, often grazed out underneath as high as livestock could reach mark the old fence-lines. White spruce, often scarred with wire, is the most common tree, but several others frequently appear: apple, cherry, poplar, hawthorn and white birch turn an old fence-line into a thin, elongated woodland – very different from the original forest but still pleasing to many living things.

These hedgerows have several values, not the least of which is to serve as windbreaks and thus to be important in saving our easily-eroded soils. Snow melt and runoff is slowed – sometimes slowed too much for an impatient farmer anxious to get on the land. Shallow tree roots can also project from the hedgerow to catch a plowshare. The move to industrialized farming with big machinery meant that too many hedgerows were casually removed; fields got bigger and erosion increased. Today we have only a fraction of the hedgerows of a century ago, but what we have still gives rural PEI much of its landscape character.

Hedgerow biology:

Given a chance, a hedgerow will expand and diversify to provide habitats for an astonishing number of plants and animals. As the backbone trees grow, shade is provided for common woodland species such as bunchberry (Cornus canadensis) and wild lily-of-the-valley (Maianthemum canadense). Many shrubs, particularly from the rose family, will appear. Ferns take advantage of the newly-shaded habitat. Birds and small mammals become highly evident, and larger mammals use the edge as a corridor along which to hunt. A hedgerow is not just a line of trees – with protection, it becomes, quite naturally, a complex ecosystem.

The European ‘quickset’ hedges of hawthorn and willow never became popular on the Island, perhaps because maintaining them is quite laborious. However, hawthorns, wild pear, cherry, rose, mountain ash and other food-producing shrubs are easily established in a hedgerow, and will survive all but the most severe attacks by wintering mice.

Establishing a hedgerow or shelter-belt begins with planning, not only in terms of shelter but also in the connections that will be established. Try to get space for at least two, preferably three lines of trees. If you want a natural look, avoid planting trees in too regimented a fashion, but give them plenty of space to grow. Inter-plant with shrubs but give naturally-invasive species a chance as well; the hedge as it grows should surprise you with something new almost every year.

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Planting Hedgerows and Windbreaks

Hedgerows, also called windbreaks or shelter-belts, once divided Island farms into a pattern of small fields. They provided shelter for livestock, protected houses and barns from winter winds and helped cool the buildings in the summer. The micro-climate in the fields was improved as the trees provided wind protection for the crops; the soil held heat and moisture and wind erosion was minimal. As farm mechanization increased the number of hedgerows decreased. Larger machines needed larger fields in which to maneuver . Soil erosion increased and important wildlife habitat corridors were lost as hedgerows were cut.

Many of the hedgerows which were not cut are old and collapsing. Old hedgerows can be revitalized and new hedgerows can be established. With good planning and the appropriate tree and shrub species a hedgerow can provide cover and food for birds and wildlife, be a source for fuel-wood and lumber, provide privacy, reduce road noise and be beautiful year round, in addition to the other benefits that hedgerows give to the land and the buildings on it.

An important factor to remember while designing and planting a hedgerow is that the effect will keep changing as the trees grow. A young hedgerow may cause snow to drop away from a driveway but as the trees mature snow may land directly on the driveway. Remember also, that the aim of a hedgerow is to reduce the velocity of the wind, letting it pass over and through the trees. A 50% density is ideal and can protect a field, orchard or building on the leeward side for a distance of up to ten to fifteen times the height of the trees. Planting shrubs with trees will create an even wall of foliage and branches from the ground up to sieve the wind.

Many species of trees and shrubs will grow well in hedgerows. Quick maturing species such as poplar, willow, red maple, and white birch can be planted with slower maturing white spruce, white ash and red oak. The fast growing species will provide protection for the other trees and shrubs and cover and food for birds. Once the slower maturing, longer living trees and shrubs are well established the pioneer species will begin to decline; they can be harvested for fuelwood or left to provide nesting sites for cavity-dwelling birds. If the trees and shrubs grow together and block too much wind, lower limbs can be pruned or some trees removed to keep the density between 40-60%.

A single row of trees and shrubs can be effective but plantings of two and three rows are better. Choose native species when designing a hedgerow as they are adapted to the local climactic changes, provide food and cover for the bird and mammal population, are readily available and are beautiful. Ideally, windbreaks should be planted at right angles to the prevailing winds. In the winter the winds are generally from the north and northwest but in the summer the winds come from the south and southwest. Another design consideration when enclosing a field is access. Angle planting at entrances will slow the wind. Access also allows cold air to leave a field. If possible leave an opening about 50 feet (15 m) wide at the low end of the field.

Newly established hedgerows can sometimes be hard to see, especially from tractor seats. Plant a row of sunflower seeds when planting the trees and shrubs in the spring. The sunflowers will grow quickly and with their large leaves and bright yellow flowers they are easy to see. They will provide some wind protection, make passer-bys smile and provide food for birds.

The best time to plant is early spring, especially if using bare root stock. If you are planning ahead, prepare the site in the fall. Rows can be plowed, compost added, and the area mulched with straw, wood chips or eelgrass to provide winter cover, add organic material and keep weeds down. The earth will be easy to dig in the spring and the mulch can be used in between the rows to keep competition down. Or individual holes can be dug, planted and mulched with wood chips. It is important to control vegetative competition until the trees and shrubs are well established. The space between the rows can be mowed, mulched or tilled and mulched.

To revitalize an old hedgerow, plant a single or double row of trees and shrubs 15 feet (4 m) from existing trees, on the most protected and sunniest side possible. Do not plant between the existing trees unless there are large gaps. When the new trees are well established remove the old trees. Plant new trees and shrubs in the old line. A word of caution: Old hedgerow trees may have wire fencing embedded in them. They are often rotten in the middle and can be dangerous to remove.

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Planting A White Spruce Hedge

Hedges provide privacy, protection from wind, and reduced erosion. On Prince Edward Island, white spruce is often planted and pruned for a hedge near a house. Without pruning, white spruce becomes a tall tree, but with annual pruning the height and diameter can be controlled. The growth will eventually be thick and lush, but to look their best the trees need to be planted properly and pruned annually.

Developing a White Spruce Hedge

      • Acquire healthy stock with a dense root mass and preferably from 1 – 2 feet (30 – 60 cm) in height.
      • If possible, plant before the long weekend in May.
      • Choose a site with full sun. If shaded, white spruce will drop its lower branches.

 

The best soil is dry, rich loam. White spruce does not tolerate wet ground.

      • If your ultimate hedge height is 6 feet (1.8 m) or more, plant the trees 2 to 2 1/2 feet (60 – 75 cm) apart. Remember, the hedge needs to be pruned annually and a tall hedge is harder to prune. If your ultimate height is less than 6 feet (1.8 m) plant the trees closer together, approximately 1 1/2 feet (45 cm).
      • Do not plant a double row of trees. The hedge will be very wide and hard to prune properly.
      • Water trees well right after planting. Mulch with wood chips to reduce moisture loss and control competition.
      • During the growing season, water if the weather is hot and dry for long periods.
      • Shear each tree annually, when the new growth appears (usually by late June). The new “flushed” growth will be light green and floppy. Do not cut the leaders until the desired height is reached.shear the sides after the new growth appears but before the end of the growing period. More new growth will appear after the shearing, which will give the hedge a softer look.
      • While the young trees are growing to the desired height and width, shear just the tips of the new growth, not all of it.
      • When the desired height and width is reached, shear most of the new growth to limit the tree’s size.
      • Shape the hedge as it grows.A square, or top heavy shape will shade the bottom branches which will kill them. The hedge will then have an open, scraggly, unattractive bottom which will not grow back.
      • Prune to have a wider bottom than top, such as a pyramid shape. Light will be able to reach the lower branches, keeping them alive and green.

 

Other native species can be pruned to be hedges, including deciduous hardwood trees. A hardwood hedge is unusual but in the right place it can be lovely and useful. Birds will use it for cover in the summer and a food source in the winter. Some suggestions:

    • Hawthorn will grow into a tight tangle of branches and thorns, and provide excellent cover for small birds. If left with a natural, “soft” finish, the plants will flower in the spring and produce haws to supply food for the birds. Prune every other year to maintain the shape.
    • Hemlock is considered one of the best choices for a sheared hedge. It is not wind tolerant but does well in partial shade or sunny locations if protected from the wind.
    • Eastern White Cedar makes a lovely hedge if the right site is chosen. Cedar will not tolerate salt spray, so do not plant near the road or where salt spray may reach it from the shore. Cedar is also intolerant of wind. Both wind and salt may cause the leaves to turn brown. 

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Come celebrate the wonderful world of owls at one of three Owl Prowls at the Macphail Homestead in Orwell on April 21, 22 and 29. The Sir Andrew Macphail Foundation will open up the Great