May / June 2000
afternoon in Soledad (Monterey County) on California's Central Coast, the wind
rises and blows steadily and strong from the northwest for several hours. In
1987, when Franciscan purchased the 800-acre ranch east of Soledad that is now
Estancia Estates, this wind was a factor that Howard Tugel, general manager
(vineyard manager until 1998), knew had to be dealt with if the vineyard was to
produce high-quality grapes.
In 1988, during redevelopment of the 660 acres originally planted by Paul
Masson in 1961-62, Estancia planted windbreaks of Casurina trees to
protect the grapevines. Spaced one meter apart and almost 50 feet tall after
nearly 12 years, the trees reduce the wind impact significantly.
When winds measure 20 to 25 mph outside the windbreaks, they are only 12 mph
inside. Winds of 7 to 10 mph are reduced to 3 to 5 mph inside the windbreaks.
As a result, Estancia has achieved a consistent set every year.
Windbreaks offer many benefits. They reduce leaf tatter, sandblast desiccation,
and wind damage to growing tips. Protected grapevines produce greater leaf area
with larger leaves, longer shoots, higher pruning weights, increased vine
capacity, longer internode length, improved pollination and fertilization,
improved berry set, and improved stomatal conductance and photosynthesis.
Evapotranspiration is improved and water stress is reduced.
Estancia reports increased bunch weight with more berries per bunch and
increased bunch number per vine. In addition, time to grape maturity is reduced
by as much as two weeks compared to unprotected neighboring vineyards.
Windbreaks improve irrigation efficiency, and they improve spraying conditions
by allowing a 10-hour spray day despite surrounding winds. Spraying of two or
three vine rows can be done with an over-the-row air-blast fan system mounted
on a Braud harvester chassis.
In the first tree-protected
vineyard section of 104 acres planted in 1988, a row of Casurina
seedlings six to eight inches tall was planted every 500 feet. The tree rows
are parallel to the vine rows of Clone-4 Chardonnay on 5C rootstock, which are
east-west oriented and spaced 10x6.
In addition, cross rows of Australian willow trees were planted in three main
avenues and along the outside perimeter of the ranch to protect the vines from
the potential wind channeling effect. Two rows of the willow trees were planted
five feet apart in a staggered pattern with 10 feet between trees. They are 35
feet from grapevines and have grown to be 40 to 50 feet tall. "Our goal
was to achieve a 'boxed in' vineyard as seen commonly in New Zealand,"
"We planted Casurina trees within the vineyard because leaf-out
occurs early enough in the growing season to provide protection when grapevine
budbreak occurs. We did not want willows in the vineyard itself because they
have a shallow, spreading root system. Also, willows are deciduous, and we did
not want to end up spraying fallen willow leaves when trying to control
Within the vineyard in 1991, a 45-acre block of Chardonnay was planted with
north-south oriented vine rows spaced 8x4. Rows of Casurina trees were
planted 250 feet apart. Tugel says new vines are spaced 6 feet 3 inches by 5
feet, and tree rows are being planted every 250 feet because their experience
has taught them that this spacing gives the most effective windbreak
Resulting vineyard sections are 250 feet wide, 1,200 or 1,600 feet long, with
trees surrounding six to nine acres of vines. In general, the area protected by
the trees extends 10 to 12 times the height of the windbreak on the leeward
side and three to five times the height of the windbreak on the windward side.
Vine rows are planted no closer than 15 feet on each side of the row of
Casurina trees. The trees are laterally pruned in February or March up
to 12 feet high to improve tractor access to the vines. Casurina trees
grow four to eight feet in height per year and have a maximum circumference of
about three feet.
a tall, evergreen Australian tree, commonly called the river she-oak. It has a
tap root rather than a filamentous root system and has dark green branchlets,
which are jointed and look like pine needles, allowing some blow through. The
tree has separate male and female flowers, and when the female flowers mature,
they resemble small pine cones. Seeds are small, winged nutlets.
The Casurina tree tolerates alkali and saline soils, is drought
resistant, and will withstand strong prevailing winds. It tolerates temperature
to 15ºF, or colder if it is well watered. Periodic cultivation is
recommended to reduce competing vegetation and improve planting survival and
growth. At least two discing passes in the tree row are needed each year for
weed control. The trees receive the same fertilization as grapevines through
the drip irrigation system.
Every winter for the first five to seven years after planting, Estancia prunes
the tree roots at about four to six feet on either side of the tree row, using
a four-foot deep single shank pulled by a D68U Caterpillar tractor at 3 to 3.5
mph. Older trees are root-pruned on one side of the tree row only (alternated
The most important benefit of planting windbreaks at Estancia is told in the
resulting grape yields. An 85-acre Estancia vineyard block grafted to
Chardonnay in 1988 that has not been protected with windbreaks has internode
lengths of less than 3/4-inch and yields only 2.5 to 3 to tons per acre.
But in the tree-protected vineyard sections, reports vineyard manager Peter
Figge, "The yield from Pinot Noir is 5.5 to 6 tons per acre, from the
Clone-4 Chardonnay is 6 to 7 tons per acre (11 to 15 pounds per vine), and from
Pinot Gris is 5 to 6 tons per acre."
Tugel and Figge agree that this boost in yields validates the use of windbreaks
in their vineyard.