Windbreak, Shelterbelt Calculator
Windbreaks, or shelterbelts, are groups of trees planted in one or more rows that protect agricultural crops and livestock from the wind. They form a vegetative ladder that effectively lifts the wind up high above the ground. Windbreaks and shelterbelts prevent the removal of topsoil by the wind, which caused the “dirty thirties” in the American mid-west. The largest shelterbelt stretches from one side of Africa to the other to stop the encroachment of the Saharan desert. Crop yields improve and native ecosystems thrive along its borders due to its ability to collect and hold water.
Prevailing Wind Breaks
Some agricultural areas have predicable wind patterns, which is seen frequently in the mountainous and plain regions of the U.S., Australia, Africa and China in particular. Where there is need to minimize a prevailing wind, trees of a wind break are grown in parallel rows perpendicular to the direction of the wind along the full length of the property line. When the wind is particularly strong, several rods may need to be planted to gradually lift the wind to the level of the leeward side of the belt. In a temperate climate, both coniferous and deciduous tree types may need to be planted to provide partial protection from the winter wind after the deciduous trees drop their leaves.
An example of a prevailing wind break would feature three rows of trees. The leeward innermost row is planted with Lombardy poplars spaced 8 feet apart, which can grow to a height of 100 feet or more. A middle triple row of evergreen Douglas fir trees is planted about 25 feet outside the first row. Trees are alternately planted to plug the wind gaps between each of the three rows of trees. An outer row of low bush type willows is planted 25 feet from the middle row. The flexibility of the willow whips provides an extremely effective “first lift” for the wind and the general permeability of the fir trees provide a natural “second lift”. Wind speed is significantly reduced by the time it reaches the poplar tree row where it is gently lifted over the tree line. In winter months, lifting the wind high above the tree line is not required because agricultural lands lie fallow in the off season.
Windbreak Calculator
Windbreak Calculator
Cross Plot Wind Breaks
A cross plot wind break is used when winds are not predominantly prevailing but circling, blowing from different directions throughout the day and during the night. Depending on the size of cropland a perimeter rectangle cross plot wind break or several cross plot wind breaks that parallel one another would need to be grown.
Rectangular cross plots have a triple wall of trees planted around the entire perimeter of a property, suitable for crop lands between 20 and 100 acres in size. Land parcels of 100 acres of more typically require many rectangular tree enclosures that are adjacent to another. Forestry companies that grow tree seedlings in open field nurseries use this parallel cross plot wind break system as well as on land fisheries.
Water Breaks
A similar technique can be used to drain wetlands or collect and store water in dry regions with less predictable rainfall. In place of a 60 foot deep tree line, a water collection/drainage ditch about 20 feet wide and 10 feet deep is excavated. In extremely dry, semi-desert regions the ditch can be lined with a liquid impermeable rubber barrier to hold water for long periods of time. An enterprising farmer could consider raising fish in these ditches. Providing the ditches are deep enough, they could sustain a fish crop through an ice over water freeze during the winters. A thriving ecosystem would also develop along these water breaks.
Berry Breaks
The same tree break technique can be used to grow a variety of berry plants in areas where wind speeds average below 20 miles per hour. Depending on your area, native berry plants could be grown like huckleberry, chokecherry and gooseberry, for example. Commercial hybrids could also be plants; blueberry, blackberry and raspberry, for example.
Shelterbelts And Climate Change
Windbreaks and shelterbelts have an amazing capability to capture carbon, typically 3 times that of a natural forest due to the fact the force of the wind presses more co2 from the atmosphere as it comes into contact with tree leaves. The shape of these wind belts funnel the wind into pockets of air that get trapped in amongst the varying levels of tree canopies. Trapped air compressed by the wind contains 10 times the carbon of a naturally prevailing wind.
Use the windbreak calculators below to calculate the number of trees by type to grow a windbreak to protect farm crops, farm animals, agricultural buildings and watersheds from excessive wind and snow blow
To use the first row windbreak calculator shown below, enter the total length in feet of a property side, sides or perimeter, Then choose spacing between trees keeping in mind that tall narrow trees like Lombardy or Tower poplar can be planted closer together than Paulownia for example. Press calculate for the total number of trees needed to plant the first row of the windbreak.
Windbreak Calculator
Windbreak Calculator
To use the second row windbreak calculator below, enter the total length in feet of a property side, sides or perimeter, Then choose spacing between trees keeping in mind that you will more than likely be planting 3 alternating rows of evergreen trees, which will be displayed after you press the calculate button.
To use the third row windbreak calculator shown below, enter the total length in feet of a property side, sides or perimeter. Then choose spacing between trees keeping in mind that willow bush is sold in root clumps that will sprout several branches and as such can be planted closer together than the 3 rows of evergreen trees planted in the second row. Press calculate for the total number of trees needed to plant the third and final row of the windbreak.