Product Code Database
The use of vine training systems in viticulture is aimed primarily to assist in canopy management with finding the balance in enough foliage to facilitate photosynthesis without excessive shading that could impede grape ripening or promote grape diseases. Additional benefits of utilizing particular training systems could be to control potential yields and to facilitate mechanization of certain vineyard tasks such as pruning, irrigation, applying pesticide or fertilizing sprays as well as harvesting the grapes.J. Robinson (ed) "The Oxford Companion to Wine" Third Edition pg 134-230, 300-341, 399-413, 551-553, 617-634, 661-692, 706-733 Oxford University Press 2006
In deciding on what type of vine training system to use, growers also consider the climate conditions of the vineyard where the amount of sunlight, humidity and wind could have a large impact on the exact benefits the training system offers. For instance, while having a large spread out canopy (such as what the Geneva Double Curtain offers) can promote a favorable leaf to fruit ratio for photosynthesis, it offers very little wind protection. In places such as the Châteauneuf-du-Pape, strong prevailing winds called le mistral can take the fruit right off the vine so a more condensed, protective vine training system is desirable for vineyards there.T. Stevenson "The Sotheby's Wine Encyclopedia" pg 19-24 Dorling Kindersley 2005
While closely related, the terms trellising, pruning and vine training are often used interchangeably even though they refer to different things. Technically speaking, the trellis refers to the actual stakes, posts, wires or other structures that the Vitis is attached to. Some vines are allowed to grow free standing without any attachment to a trellising structure. Part of the confusion between trellising and vine training systems stems from the fact that vine training systems will often take on the name of the particular type of trellising involved.J. Cox "From Vines to Wines" Fourth Edition, pg 40-49 Storey Publishing 1999 Pruning refers to the cutting and shaping of the cordon or "arms" of the grapevine in winter which will determine the number of buds that are allowed to become grape clusters.K. MacNeil The Wine Bible pg 26-29 Workman Publishing 2001 In some wine regions, such as French wine, the exact number of buds is outlined by Appellation d'origine contrôlée (AOC) regulations. During the summer growing season, pruning can involve removing young plant shoots or excess bunches of grapes with green harvesting. Vine training systems utilize the practice of trellising and pruning in order to dictate and control a grape vine's canopy which will influence the potential yield of that year's crop as well as the quality of the grapes due to the access of air and sunlight needed for the grapes to ripen fully and for preventing various grape diseases.Oz Clarke Encyclopedia of Grapes pg 18-27 Harcourt Books 2001
Historically, regional tradition largely dictated what type of vine training would be found in a given area. In the early 20th century, many of these traditions were codified into specific and regulations such as the French AOC system. The widespread study and utilization of various training systems began in the 1960s when many New World wine regions were developing their wine industry. Without the centuries of tradition that influenced Old World winemaking and viticulture, vine growers in areas like California wine, Washington wine, Australian wine and New Zealand conducted large scale research into how particular vine training systems, pruning and canopy management techniques impacted wine quality. As research in this area continued into the 21st century, new vine training systems were developed that could be adapted to the desired wine making style as well as the labor needs and particular mesoclimate of the vineyard.
In viticulture, growers want to avoid any part of the cordon from touching the ground because of the vine's natural inclination to send out suckers or and take root in that area where the cordon is touching the ground. Ever since the phylloxera epidemic of the 19th century, many vines are Grafting on phylloxera-resistant rootstock. However, the "top part" of the grafted vine is still very susceptible to the phylloxera, and should a part of that vine take root both the daughter and the original mother vine will risk being infected by the louse. Additionally this daughter vine will leech resources of water and nutrients from the mother vine which can diminish the quality of both vines' grape production.
Other reasons for vine training involve setting up the vineyard and each individual vine canopy for more efficient labor usage or mechanization. Vines that are trained to have their "fruiting zone" of grape clusters at waist to chest height are easier for vineyard workers to harvest without straining their bodies with excessive bending or reaching. Similarly, keeping the fruiting zone in a consistent spot on each vine makes it easier to set up machinery for pruning, spraying and harvesting.
The grape clusters receive some benefit from receiving direct sunlight through enhanced ripening of various phenolic compounds that can contribute to a wine's aroma and quality. In addition to having decreased physiological ripeness, excessive shade will negatively impact a grape's quality by causing increases in the levels of potassium, malic acid and pH in the grapes while decreasing the amount of sugar, tartaric acid and Wine color . Beyond a lack of sunlight, excessive shading limits the amount of air circulation that can take place within a vine's canopy. In wet, humid climates poor air circulation can promote the development of various grape diseases such as powdery mildew and Botrytis cinerea.
Cordons are trained in either a unilateral (one arm) or bilateral (two arms) fashion with the latter resembling the letter "T". The cordons of grapevines are most commonly trained horizontally along wires as in the Lyre and Scott Henry systems. However, notable exceptions do exist, such as the "V" and "Y" trellis systems which elevate the cordon to various angles that resemble their namesake letter. Note that vertical trellising systems, such as the VSP system often used in New Zealand, refer to the vertical orientation of the fruit canes in an upward manner and not the cordon "arms" of the vines.
From the cordon, emerge from the bud that eventually develops mature bark and becomes the fruiting cane from which grape clusters will emerge. These canes can be positioned and trained to whatever angle is desired by the grower. Typically, they are positioned upwards but they can be bent into an arch such as a Pendelbogen or Mosel arch system, or trained to point downwards such as the Scott Henry and Sylvos system. The latter method requires more labor-intensive trellising and training for Vitis vinifera vines which are naturally more inclined to grow upwards rather than down. In systems such as the Scott Henry, this downward growth is achieved by the use of movable wires that first allow the canes to grow upwards until about 2 to 3 weeks before harvest when they are then shifted downwards where the weight of gravity on the hanging grape clusters helps keep the canes pointing down.
The leafy foliage of a grapevine's canopy will be dependent on the particular grape variety and its propensity for vigorous growth. These leaves emerge from shoots on the fruiting cane in a manner similar to the grape clusters themselves. A vine is described as "vigorous" if it has a propensity to produce many shoots that are outwardly observable as a large, leafy canopy. The ability of the grapevine to support such a large canopy is dependent on the health of its root system and storage of carbohydrates. If a vine does not have a healthy and extensive root system in proportion to its canopy, then it is being overly vigorous with parts of the vine (most notably the grape clusters) suffering due to lack of resources. While it may seem that more foliage would promote increased photosynthesis (and such carbohydrate production), this is not always the case since the leaves near the top of the canopy create excess shading that hinders photosynthesis in the leaves below. One of the objectives of vine training is to create an "open canopy" that allows limited excess leaf growth and allows plenty of sunlight to penetrate the canopy.
One of the most common manners of classifying vine training systems now is based on which parts of the vines are permanent fixtures which determines which parts of the vine are removed each year as part of the winter pruning. With a cane-trained system, there are no permanent cordons or branches that are kept year after year. The vine is pruned down to the spur in winter, leaving only one strong cane which is then trained into becoming the main branch for next year's crop. Examples of cane trained systems include the Guyot and Pendelbogen. With spur-trained systems, the main branch or cordon is kept each year with only individual canes being pruned during the winter. While vines that are cane trained will often have a thin, smooth main branch, spur trained vines will often have thick, dark and gnarled cordon branches. Many old vine vineyards will often utilize spur training system. Some examples of spur-training systems include the goblet or bush vine systems, and Cordon de Royat. Some systems, like the Scott Henry and VSP Trellis, can be adapted to both spur and cane training. Vine systems that are classified as either cane or spur trained may be alternately described by the way they are pruned in the winter so systems that are described as "cane-trained" will be spur pruned while systems that are "spur-trained" will be cane-pruned.
Within these larger classifications, the vine training system may be further distinguished by the canopy such as whether it is free (like goblet) or constrained by shoot positioning along wires (such as VSP trellising) and whether it includes a single curtain ( Guyot) or double ( Lyre). For cordon and many other spur trained systems, they could be described as unilateral (utilizing only 1 arm or cordon) or bilateral with both arms extending from the trunk. Two other classifications, based on trellising, are whether or not the vine is "staked" with an external support structure and the number of wires used in the trellising. Vines may be individual staked either permanently, as many vineyards along the bank of the Rhone Valley which are at risk of wind damage, or temporarily as some young vines are to provide extra support. Within a trellis system fruiting canes and young shoots are attached to wires strung out across the rows. The number of wires used (one, two, three) and whether or not they are movable (such as the Scott Henry) will influence the size of the canopy and the yield.
+ Partial list of common vine training systemsTable references:
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