|Abstract or Summary
- The phrase "canopy management" has recently become trendy in many New World grapegrowing areas.
Interestingly enough, the concepts are not new and are generally acknowledged in Old World viticulture,
though often these empirical observations are misinterpreted, as we will soon show. It was Nelson
Shaulis of Cornell University who developed ideas of canopy management, especially for New World
audiences, which culminated in his description in 1966 of the Geneva Double Curtain.
Shaulis' studies showed him that the primary limiting factor in modern vineyard production was
sunlight, once pests, diseases, and weed competition were overcome. Widely spaced rows alternating
with dense vine canopies was standard vineyard practice. While the exterior leaves were well exposed,
there was a high proportion of shaded interior leaves and fruit, which was shown to have negative
effects on both yield and fruit composition. The solution was to divide dense canopies, and he found that
an improved trellis system was preferable to closer row spacing.
Although published over twenty years ago, there has been a reluctance to accept some of these basic
biological principles. Probably a major reason was that the initial studies were with Labruscana grapes
(Concord) and many believed the same results would not apply to Vitis vinifera, the European
winegrape. Also, many believed that similar responses would not be obtained in "sunny" climates, like
California or Australia. These same people had obviously never measured light levels in the center of
dense canopies - they are equally low in "sunny" as in "cloudy" climates, and both inferior from a vine
physiology point of view! Another major reason was the reluctance of researchers to evaluate other
peoples' ideas or systems. This disturbing trend is still evident. While some may claim lack of
mechanization as an impediment to local evaluation, it is noteworthy that Shaulis developed GDC for
both mechanical harvesting and pruning.
There were, however, a few converts to the Shaulis approach. During the early 1970's, Dr. Cesare
Intrieri of Italy, Dr. Alain Carbonneau of France, and I (Richard Smart of Australia) learned from
Shaulis and further developed these ideas for vinifera winegrapes. The results were equally encouraging,
and now, in the late 1980's, canopy management is being actively researched throughout the New
Over centuries of trial and error and empirical observation, the Europeans have determined vineyard
factors important for wine quality - and, by the way, vineyard factors are regarded as more important
than cellar practices generally! Several adages come to us from Europe, to wit: "A struggling vine makes
the best wine" and the old favorite "High yield gives lower quality". I understand why there is support for these ideas and recognize that they do represent reasonable observation. But, like most empirical
dogma, they are not necessarily correct. They show association only and do not prove cause and effect.
A feature of both low vigor ("struggling vines") and low yields is that the canopies are open. That is,
most leaves and fruit are exposed. As one increases yield, this is invariably accompanied by an increase
in shading. Similarly, high vigor means long shoots and more and bigger leaves, and this also increases
shading. Perhaps it is not the "high vigor" or the "high yield" that cause reduced quality, but more
shading. This is the central idea to what we regard as proper canopy management.
The last two decades have witnessed many studies of canopy microclimate and effects on wine quality.
These studies have demonstrated similar responses with a range of varieties and over a range of
climates, from "hot" to 11 cool". I have personally witnessed experimental wine tasting where wine
judges (competent enologists all) thought they were tasting wines from different regions and were
impressed to learn they all came from the same vineyard, the only difference being in canopy
We might add a word here about our Ruakura philosophy of canopy management. Our primary aim is to
improve quality. It turns out that as we improve quality by canopy management, yields also increase.
We can live with that. Also, we are interested in mechanization. We believe the future lies in
mechanization of all vineyard operations, including harvest, winter pruning, and summer pruning as
well as cultivation and spraying. While we understand that Oregon growers are not at the moment as
concerned with mechanization, that may change along with immigration laws in the future. Our goal is
to maximize quality and minimize unit cost of production.
This article is written as a series of questions and answers - we anticipate the question, then answer it!
Hope we get the questions right!