Violins and very cold weather – a hypothesis

A
There is considerable controversy surrounding reasons why instruments made by the artisans of Cremona in Italy in the late 17th and early 18th centuries sound superior compared to modern instruments. The famous violin-making families of Amati, Stradivari, and Guarneri certainly included many highly accomplished craftsmen, and the popular belief is that the skills of these Cremonese artisans, combined with either a secret ingredient or undocumented process, gave their instruments the rich sound so highly admired by professional musicians. The nature of that secret ingredient has been the subject of conjecture for many years and is still fuelling discussion. Theories have included the development and use of a specially formulated varnish applied to the wood to protect it, drying the wood in ovens, the re-use of old wood taken from castles, and soaking the wood in water to get rid of supposedly harmful chemicals before seasoning.

B
However, no basis has been found for these possible explanations. There is no documented evidence of wood being artificially dried by violin-makers, and this process was most likely unknown to these artisans. Nor can seasoning – the practice of leaving wood for the moisture to evaporate naturally – be invoked as a possible explanation, as considerable variability exists in the lengths of seasoning periods, even among individual makers. Instruments made by the most renowned of all violin-makers, Antonio Stradivari (1644–1737), have seasoning periods as short as seven years and as long as 31 years, for example. A secret varnish has yet to be demonstrated, despite considerable scientific analyses that include ultraviolet photography, electron microscopy, ion backscattering and x-ray investigations. Finally, some have suggested that Stradivari used wood taken from castles. This theory has been discounted because analyses on numerous instruments attributed to Stradivari demonstrated ages for the wood that were contemporary with his lifetime.

C
Violin-makers have always known that the secret of a quality instrument lies in the selection of the wood. Maple wood (*Acer spp.*) is preferred for the back, ribs, and neck of the instrument while spruce (*Picea spp.*) is often used for the top. These woods have superior acoustical and mechanical properties, having the least loss of energy through internal friction compared to other woods. For example, spruce cells are light, physiologically simple, hollow, and rigid—ideal properties for enhanced acoustic quality. Only trees that have grown in thin, poor soils at higher elevations on north-facing slopes have the dense wood grain that helps instill a superior tone in violins. Long winters and cool summers produce wood that has the slow, even growth ideal for producing quality sounding boards.

D
Stradivari and other eminent Italian violin-makers of the 17th and early 18th centuries had neighbouring workshops in Cremona and would most probably have used the nearby high forest slopes of the southern Italian Alps for their supplies of spruce wood. A probable location is the famous “Forest of the Violins” in the Parco Naturale Paneveggio in the eastern part

E
Wood with high density can, however, be found in trees growing in a variety of habitats and environmental settings in numerous higher-elevation locations throughout the world. Hence, an account of the Cremonese craftsmen’s superior sound quality based solely on wood properties is insufficient. Instead, could the superior sound quality be explained by a combination of wood properties, environmental characteristics, and macroclimatic conditions? Could the wood used by the Cremonese makers have had particular physical characteristics that were perhaps time-specific? These were questions that required more thorough research.

F
The well-documented Maunder Minimum (1645–1715) was a period characterized by a scarcity of sunspots and a reduction in overall solar activity. It coincided with a sharp dip in temperatures and a period of extremely cold weather in western Europe. Analyses of high-elevation forest areas of the European Alps reveal a long period of reduced growth rates between approximately 1625 and 1720, identified by the narrow rings visible in the cross-sections of tree samples from that era.

G
It seems likely that the narrow tree rings that identify the Maunder Minimum in Europe played a significant role in the enhanced sound quality of instruments produced by the Cremonese craftsmen. Narrow rings would not only strengthen the violin, but lend the wood a high degree of density—the property so important for acoustic resonance. It is surely significant that Stradivari’s working lifetime coincides exactly with this climatic period, and that to fashion the most prized and valued instruments of his ‘Golden Period’ (1700–1720), he would have used the only wood available to him, i.e. from trees that grew during the Maunder Minimum. The onset of the Maunder Minimum at a time when the skills of the Cremonese violin-makers reached their peak perhaps made that crucial difference in the violin’s tone and brilliance. Furthermore, the conjunction of elevation, topography, soil properties and a deterioration in climate was temporally unique—climate conditions with temperatures such as those that occurred during the Maunder Minimum simply cannot and do not occur today in areas where the Cremonese makers obtained their wood.