Weather Risks: Strategies
to Mitigate the Risk of Wind Damage
Table of Contents
For more information
- What it is
- When it occurs
- Where it occurs
- What can you do
This in the 5th in a series to help apple and tender fruit growers
in Ontario assess the weather risks that can damage their trees
and crops. It is important to recognize the weather risks at each
location, and develop strategies to reduce or eliminate the impact
on your business operation.
What it is
Winds may break branches (especially the tree's leader), cause
blowing soil and fruit russeting, bruise fruit and/or knock it
off, snap graft unions (which kills the tree), and stress tree
support systems, especially when carrying a full crop load, and/or
if the ground is saturated. Windy conditions can hamper spray
operations, discourage bee activity and pollination, make ladder
work hazardous, and distract harvest workers. Diseases like fire
blight, canker and fruit rots can gain entry through damage from
When it occurs
Wind damage often occurs when weather systems are swiftly changing
from low pressure to high pressure, changing from moist, humid air
to cooler, drier air. Thunderstorms build up in the unstable air,
and the leading edge of the storm front carries strong or gusty
winds. Spring weather often includes strong winds that limit spraying
time, and may reduce bee activity and fruit set. The fall harvest
sometimes coincides with hurricanes moving up from the south, with
strong winds and heavy rains that loosen soil around roots of trees
that are heavy with crop.
Where it occurs
Wind damage is a common weather risk for tree fruit growers, because
severe storms are frequent throughout the year and often include
strong winds. Tornadoes occur less frequently, but cause much more
damage in localized areas.
What can you do
Some of these potential mitigation strategies may help reduce or
eliminate damage due to winter injury:
- Production insurance (PI):
Production insurance can cover yield loss from fruit blown to
the ground, and unmarketable fruit with limb rubs. It may cover
future yield loss from broken limbs or graft unions. For apples,
tree insurance can also cover trees broken off at the union if
the loss is greater than 7% of your total trees. PI is purchased
well before the season, and can give you peace of mind that at
least some of your input costs will be covered. Your premiums
will depend on the coverage you choose, your claim history, and
the yield potentials of your orchards. Over time, your premiums
can be reduced if you are lucky enough not to have claims. However,
some growers struggle with the premium costs (especially in their
start-up years or if they have claims) and the fact that PI is
not intended to fully cover your loss, either in yield or price.
There is also the problem of reduced coverage levels in the years
after your crop is reduced, due to the effect of the loss on your
long-term average yields. Also, spot loss insurance is not available,
so growers with multiple orchard sites may be penalized when good
yields occur on the non-damaged sites.
- Windbreaks: Windbreaks
located on the windward side of your orchard will protect trees
and fruit for a distance of 10 times their height. Reducing wind
in this area can improve spraying conditions, bee activity for
pollination, fruit quality through less russeting from blowing
soil, and reduce graft union breakage. However, windbreaks take
time to establish and take some acreage out of production.
- Tree row orientation:
Aligning tree rows with the direction of the prevailing wind will
allow wind to flow through the orchard without damaging trees
or fruit. Depending on the topography and layout of your farm,
this may not always be possible or desirable - usually, a north-south
orientation of rows is preferred for optimum sunlight interception.
However, on the windiest sites, it may be prudent to choose the
- Tree support: Trees
that are not supported immediately after planting will blow in
the wind, which alters their growth and reduces subsequent fruiting.
Early support will also avoid union breakage, or limb breakage,
especially the leader. If the full trellis cannot be installed,
use a temporary stake to support the leader and prevent breakage.
- Strong anchorage:
Recent experience with strong winds, including tornadoes, has
shown that when the end anchors hold, the trellis holds. Maximizing
the strength of the trellis, especially the end anchors, is key
to avoiding wind damage. Invest in materials and proper design
to match the weight of your crop and the worst expected winds
to reduce breakage and limb rubs.
- Limb spacing: Properly
spaced scaffold branches will help reduce fruit damage from limb
rubs. This structure has the added advantage of better light interception
and improved fruit quality. However, more detailed pruning has
increased labour costs.
- Summer pruning: Removing
first year branches around the fruit before harvest will reduce
limb rubs in windy weather. Summer pruning can also improve spray
penetration and improve fruit colour and quality. However, there
is an increased labour cost for summer pruning.
Avoiding or reducing wind damage is an ongoing challenge for many
fruit growers. The extensive damage from a short period of strong
winds is discouraging, and the subsequent loss from diseases can
be devastating. As erratic weather patterns produce more wind events,
growers should consider more options to avoid wind damage. The investment
in intensive orchards and high-valued varieties may encourage more
investment in wind strategies in the future.
For More Information
For more information:
Toll Free: 1-877-424-1300