Silviphonics: Sound In Timber

Vincent Wozniak O’Connor

The unique mechanical and conductive properties of wood have made it the material of choice for making musical instruments from antiquity to the present. Ancient lyres, rattles and slit drums all rely on the acoustic properties of timber to convert human actions into sound. While wooden instruments are used to produce sound, trees themselves make sound without human intervention. This essay focuses on the material connection between timber and sound. It examines sound outputs derived directly from timber, considering multiple methods for deriving sound from timber. By examining the connection between instruments and timber, the role trees play in physically shaping instruments is highlighted as having direct influence in coloring the sounds they produce. 


Artists engaged with the relationship between sound and timber include instrument builders and sound and installation artists, who have chosen timber as the basis for making sound as a transmission medium or in field recording interventions involving live trees. Artists Laurie Anderson and Doug Aitken use the physical properties of timber, such as acoustic velocity, as a basis for their sound sculptures and installations. Research into the qualities of timber reveals shared histories between bioacoustics, instrument building and the sonic arts. The Xylophonic phonograph experiments of the 1960s, including John Cage’s Cartridge Music (1960), connects early plant bioacoustics with a shared history in hardware hacking and experimental sound. Recording directly from plants and living trees, Patrick Farmer and Robert Birch contribute to a framework of Silviphonic instrument building focusing on the vibrational quality of living trees. Developing from Farmer and Cage’s piezoelectric experiments, my own recording projects are considered here as they highlight the readymade acoustic qualities of forestry grown pines, relating silviculture to sound. The musical aspects of trees in the wind will also be examined, as they possess similarities to Aeolian instruments. The basis of these sonic practices relies on the qualities inherent to wood that enable it to radiate and transmit sound. This essay explores these practices as they expand the variety of sound outputs produced by timber.

Instruments and Timber  


Most instruments are built largely with plant-derived materials, and the practice of using plants for instrument building probably predates the earliest examples of instruments we have (Wegst 2006: 1439).This longstanding tradition relies on both the resonant and mechanical qualities of timber. The sounds made by instruments have developed through the responses to striking, bowing and scraping, but also the conductive properties inherent to timber that enable it to radiate sound.The material qualities of timber vary greatly according to the density of individual species, and even their dimensions are tied to the development of certain instruments, for example, tubular drums carried with them the dimensions of hollowed-out trees (Sachs 2012: 31).Instrument building exploits the densities and anatomy of individual tree species, designating them as desirable for very specific uses. 


Discussing the specificity of this relationship between individual timber and corresponding instruments, wood scientist and CNRS researcher Iris Brémaud explains that timber species “play a direct role in idiophone instruments, such as xylophones, in which wood constitutes the primary vibrating body” (Brémaud 2012: 807). The bars of a xylophone are examples of timber idiophones, resonant bars of different pitches that are struck to produce tones based on the resonation of the entire object. Earlyxylophonesare described by Curt Sachs as “leg xylophones” and were played by laying timber sections across outstretched legs (Sachs 2012: 31). Subsequent iterations and evolutions of this instrument are also described by Sachs as arrangements, including the log Xylophone, which replaced the human legs with lengths of timber and included a hollow carved into the ground. While Sachs is relatively brief in discussing the evolution of the xylophone, he compiles more detailed information on the construction of large scale slit drums that are constructed by forming an entire tree into a hollow chamber and played by stamping or striking. The tree-scaled slit drum operates as an instrument on nearly the scale of a living tree and speaks to the key role trees play in instrument making as the materials used to transmit musical sounds to our ears. The use of individual timbers for certain instruments has a consequent effect on the sound being produced, as Brémaud explains: “In string instruments, their importance is widely recognized for soundboards, which serve to transmit and radiate the vibration of a string, and act as a “filter” that colors the timbre” (Brémaud 2012: 807).


Within specific fields of instrument building, the selection of individual trees plays a role beyond their availability for harvest. For example, determining the provenance of resonance wood from thirty-seven violins within the collection of the Luigi Cherubini Conservatory in Florence has been undertaken to locate the specific forests where the wood used was harvested(Bernabei, Bontadi and Rossi Rognoni 2010: 196). By determining the age and geographic location of the wood utilized in making such instruments we learn of specific forests where the timber was sourced and subsequently supplied to master violin makers. This research has led to the discovery of specific locations of timber that had been sourced in Ötztal, Austria; Northern and Southern Bavaria; and Bibbiena, Tuscany. The selection of timbers for instrument making has also evolved with instrument development and fluctuating access to timber sources beyond local availability. The trees traditionally designated for flute making in Europe, such as Boxwood (Buxus sempervirens) and Plum (Prunus domestica), came to be replaced by exotics due to the availability of the “green gold” of non-European species accessed via colonial bioprospecting aimed at unearthing new cash crops (Schiebinger2007: 34). Materials and manufacturing engineer Ulrike Wegst has described the progression from common hedge and fruit trees to exotic timbers, including African blackwood (Dalbergia melanoxylon) and Brazilian rosewood (Dalbergia nigra). According to Wegst, shifts in the use of the timber species was due to the favorable structural character of the exotics, which allowed for instruments to be turned and drilled with greater accuracy. The role of timber in shaping the tonal and physical character of instruments is greater than its role in coloring their sound and influences instrument manufacture despite the departure from using whole trees as instruments. The sound of instruments is inherently based on this departure from trees themselves, while the slit drum and individual stands of trees continue to play a role in physically and sonically shaping instruments. 


The specificity of this bond can be seen not only in the physical dimensions of trees but also the ecological conditions of wood growth. Trees are shaped by the stresses and conditions particular to their environment, and luthiers and musicians can hear the influence of timber grown within specific locales in the instruments derived from different locations. Instrument makers have historically favored and differentiated between boards made from timber derived from the same tree species, and this practice is documented in wood archaeology research conducted by Mauro Bernabei et al, which determined that Tuscan violin makers selected instrument boards based on the appearance and regularity of veining (Bernabei, Bontadi and Rossi Rognoni 2010: 196). According to dendrochronological comparisons, Tuscan violin makers selected narrow rings for smaller instruments, resulting in decreased variations and greater regularity in the sounds produced by different instruments. In another example, Aldo Zorzitells the story of an ancestor in Val di Fiemme in Paneveggio, Italy, who was building a cabin from boards of locally cut timber and was approached by a master violin maker who saw a tree trunk among the building materials that displayed characteristics desirable for the manufacture of violins (Zorzi 1985: 13). The timber was destined to be used as building materials, however, the violin maker managed to acquire the tree, as their sonic characteristics might otherwise be wasted on a cabin. The timber used in traditional Italian violin making is named “Abeti di Risonanza,” or Resonance Spruce, and while there are anatomical and structural variations present in individual logs, which can be visibly discerned by luthiers, the location and external climatic conditions also generates special sonic characteristics in the timber. The Paneveggio Forest of The Violins produced the timber used to make the Stradivarius violins, regarded as belonging to the pinnacle of violin making. During 1645–1715 the Paneveggio forests were subject to special climatic conditions, the Maunder Minimum, with reduced solar activity, which has been attributed to improving the tonal qualities of timber. As speculated by Lloyd Burckle and Henri Grissino-Mayer, researchers within tree ring science, the Maunder Minimum had a profound effect on the growth of the timber: “longer winters and cooler summers produced wood that had slower, more even growth, desirable properties for producing higher-quality sounding boards” (Burckle and Grissino-Mayer 2003: 41).

Instrument Building and the Sonic Arts: Velocity and Resonance


The diverse character of timber is caused by the morphologies of individual species. The nature of this variability is put to use in the fabrication of instruments, from violins to drumsticks; by examining the transmission of sound it is revealed that the speed of sound is inherently faster when travelling through timber than through the air itself. The speed of sound in air is 343 m/s, while in wood the speed of sound increases greatly, ranging between 3300-5000 m/s. Observing this characteristic, philosopher Richard Green Parker provides an example of listening to sound travel through a board: “If a person lay his head on a long piece of timber, he can hear the scratch of a pin at the other end, while it could not be heard through the air” (Parker 1846: 86). Sound radiation in instruments is based on the coupling between the timber and the air itself, into which timber transmits the vibratory energy of the string, radiating the sound (Wegst 2006: 1445).


While the characteristics of wood and their relationship to resonance have been examined through instrument building, artists have also examined the transmission of sound through the timber itself. With Doug Aitken’s Sonic Table (2012) and Laurie Anderson’s Handphone Table (1978), timber density is employed to transmit sound to listeners. Anderson uses the conduction of sound within a wooden table, with dowel rods mounted to transducers, to transmit sound through the bones of the listener’s forearms and into their hands, cupped over their ears. The playback system hidden beneath the apron of the table conveys two different lyrics at the opposite ends of the table: “Now You in Me Without a Body Move” and “And I Remember You in my Bones.” The audience experiences sound transmission through the table top and through their bones, which function as sound conductors for recordings that are “heard/felt” (Celant2014: 258). Explaining the work, Germano Celant quotes Anderson’s concept of a conductive listening, whereby sound was heard by the forearms as well as the ears: “you heard the final piece using the same gesture involved in its invention, closing the circuit, your head in your hands, listening, listening through your bones” (Celant 2014: 296).


Doug Aitken’s Sonic Table (2012) is a timber percussion instrument in which zones of a table are “carved and tuned to the same family of pitches” (Wainright 2012). The surface of the table is drummed upon by the audience, who are tasked with playing the instrument as a social device originally devised as a tool for overcoming the awkwardness of art-world dinners. Both Aitken and Anderson’s works examine the resonant characteristics of timber boards and specify approaches to instrument building that are based on the conductive and resonant applications of timber manufacturing rather than the fabrication of traditional instrument forms.  


The resonance of timber can be heard even in simple instruments, such as the one used in Michael Gordon’s Timber (2009), whichutilizes untuned two-by-four planks cut into different sizes and played by six percussionists with a shifting rhythm and resonance. The sound made by the two-by-fours, according to one of the performers, Mark McCurdy of Mantra Percussion, is unlike the primary fundamental of a xylophone bar. Instead, McCurdy described it as an “angelic chorus” arising from the interplay of harmonics produced by the untuned beams (anon. 2011). Gordon cites the Simantra – devised by composer Iannis Xenakis – as the basis for a specifically untuned percussive composition that produces a phasing effect by moving the accent of sound from one player to another. For Persephassa (1969), Xenakis encircles the audience with percussion instruments, including both metal and wooden Simantra,upon which imitative rhythms are passed between performers (Harley 1994: 293). Xenakis’s Simantron was an adaptation of an Orthodox liturgical instrument, the Sēmantron, a sonorous hardwood beam that is played with mallets: varying the positions of the mallet strikes changes the pitch produced by a single board (Chew and Mathiesen 2017). The compositions devised by Xenakis and Gordon use timber boards for their resonance and reveal the sonorous character contained within untuned timber beams.  


Aside from instrument building, the qualities of timber as transmission medium are exploited in a field recording series of abandoned rail bridges undertaken by field recordist Jay-Dea Lopez (Lopez 2017). Here, the beams of a rural railway bridge became the medium through which a field recording documents insect life in Northern New South Wales. Exploiting the conduction of vibrations through the timber trusses, Lopez recorded the sound of insects living in decaying rail pylons by inserting contact microphones into cracks and splits in the surface of the timber. The popping, scratching and squeaking of the insects living inside the beams brings to mind Richard Green Parker’s example of listening to a pin scraping a board, showing how the acoustic velocity of timber can be used as the basis for recording minute sounds. The audio recorded by Lopez documents the life of insects in a decaying timber structure and the wood-borne transmission of sound.

Bioacoustics and Acoustic Emissions


Timber has a relationship to sound outside of its use in vibrating instrument boards, as trees themselves are full of sound in the form of acoustic emissions. Sound can be generated by trees, one example being “cavitation,” which generates ultrasonic acoustic emissions in vascular plants (Pena and Grace 1986: 515). Cavitation is the formation of air in solids or bubbles in liquids. In the context of plant biology, Alberto Vilagrosa et al explains: “This phenomenon occurs in the xylem of vascular plants when the tension of the sap within a conduit becomes high enough that dissolved air within the sap expands to fill vessels or tracheids” (Vilagrosa, Chirino, Peguero-Pina, Barigah, Cochard and Gil-Pelegrín 2012: 63). Field recordings by Bernie Krause include audio from cavitation events that were inadvertently recorded from “singing trees” (Krause 2009). Krause describes a field recording session in Utah aimed at detecting the ultrasonic vocalizations of bats. While attempting to record the bats, Krause accidently picked up the emissions of a Cottonwood tree as it generated ultrasonic audio due to drought stress. While Krause’s bat detector revealed a spectrum of audio unanticipated by him, John Milburn documented audio events generated as a by-product of the workings of plant hydraulics as early as 1966. The audio experiments of Milburn used handmade acoustic detection equipment to register the pops and clicks caused by drought stress in the leaves of the Castor oil plant (Ricinus communis). Specific to his experiments was an assemblage of hacked music playback equipment and laboratory supplies, including a phonograph cartridge modified into an acoustic probe made from an electrical solder (Milburn and Johnson 1966: 45). The solder was used to impale individual leaves of a Castor oil plant, which were screened for cavitation-related audio. With this botanical-acoustic interface Milburn proved plants produced sound as a result of water tension changes in plants, with cavitation generating clicks. According to Milburn sound production has been  observed accompanying cavitation in plants, with sap rupturing and clicking when water loss was induced in a cut Ricinus leaf that was exposed to the heat of a 100 watt lamp. 


The piezoelectric phonograph cartridge used in Milburn’s recording apparatus shares a musical feature with a “xylophonic” recording device mentioned by field recordist Martin Michener. Xylophonics best describes the sounds of xylon (Plowman 1976: 141), indicating the wood associated with timber boards (Thayer 1889: 432). The piezoelectric qualities of the phonograph cartridge allow for acoustic detection to occur by means of direct contact with the timber and the sonic potential of “sounds inaudible without amplification” (Bernstein 2014: 559). As readily available components, which could be modified for audio experiments, phonograph cartridges formed the basis of Cage’s Cartridge Music (1960). Cartridge Music featured multiple modified turntable cartridges used to articulate indeterminate compositions for which the phonograph needle was replaced by “pipe cleaners, wires, feathers, Slinkies, matches, toothpicks, nails, twigs, cocktail parasols, and miniature American flags” (Kelly 2009: 115). Both Milburn and Cage modify the phonograph cartridge to pick up sound as it is conducted through timber in the form of acoustic emissions, or in an exploration of the sonic characteristics of everyday materials.

Acoustic Testing and Forestry  


The term Silviphonic describes the interventions designed to access the sound of trees standing in a forest. Silviculture deals with the care and growth of trees in forests and the management of timber production. Within the evolution of silviculturalpractices, sound as a tool has developed from the percussive use of mallets to drum the surface of trees. This drumming was a method employed by silviculturalists to inspect decay in a tree; the trained ear listened for “the tell-tale drum sounds of internal cavities” (Ross 2015: 78). The testing of standing timber has developed from these simple sounding devices to sophisticated acoustic imaging and grading equipment, including handheld testing devices used to assess internal rot with 3D acoustic tomograms in order to make assessments about the stability and density of trees (Wang and Allison 2015: 80). Equipment specifically developed to assess and grade the longitudinal acoustic velocity of standing timber includes the Sylvatest Duo, Treetap and TreeSonic. This equipment uses acoustic resonance and wave transmission tests to verify the density of entire logs prior to processing. Forestry researchers Ross Dickson, Bill Joe, Paul Harris, Stephen Holtorf and Col Wilkinson describe the promise of acoustic testing as “a means by which silviculturalists can understand the effects of site, silviculture and genetics on the stand, thus guiding prudent silvicultural policies and genetic strategies” (Dickson, Joe, Harris, Holtorf and Wilkinson 2004: 261). Acoustic segregation tests taken during timber grading tests are used to assess pine as a conductive medium, using velocity as a basis for equating fast transmission values with denser timber. 

Silviphonics: Tree-scaled Idiophones 


While entire trees are assessed using sound with equipment such as Sylvatest Duo and Treetap, the acoustic qualities of individual standing trees are the focus of Silviphonic interventions that use the conduction of audio through living trees as a basis for audio recordings. Recent work by artists Patrick Farmer and Rob Birch features recordings from trees. Patrick Farmer’s field recording Aeolian Trees (2007) is a recording of the aerodynamic properties [and the attendant sonic qualities] of gorse, pine and oak foliage. These recordings document individual tree species across the UK. Rather than providing renderings of forest situations, Farmer’s field recordings document the individual acoustic qualities of trees and foliage when animated by the wind. Farmer’s Aeolian Treesfocuses on trees as the subject of a recording rather than a passive "environmental" backdrop. Robert Birch’s collaboration, part of The One Tree Project (2017), experiments with taking recordings from different surfaces on a single Pin Oak (Quercus palustris) on the Washington University campus in Saint Louis. The One Tree Project examines land use and resource legacy by examining a single oak from the historic pin oak allée on the Danforth campus that was being removed as part of a campus redevelopment (Duffy 2017). Birch’s investigations involve cutting into the tree bark and embedding an ElectroVoice model 805 crystal contact microphone, a microphone historically used for recording insect activity in trees. The sounds documented by Birch are the results of “playing” the surface of the pin oak with a mallet, handling the tree surface and speaking into a hole bored into the bark (Birch 2017). 


Instead of screening for bioacoustic emissions, the recording interventions of Farmer and Birch focus on listening to the sounds of trees. Comparing the sounds of the two separate piezoelectric methods, the experiments of Milburn result in clicks tracked on an oscilloscope, while for Farmer and Birch, the results of connecting audio equipment to vegetation produced sounds full of the bowing and brushing of leaves and the minor collisions of branches. The jagged scratching of the twigs and timber needles in recordings of Cartridge Music display the recognizable handling sounds of piezoelectric instruments, whereas Farmer’s Aeolian Treesresemble the reverberation of the long wire recordings of Alan Lamb or Jodi Rose’s recordings of singing bridges.

Contact microphone embedded within a pin oak by Robert Birch as part of The One Tree Project.

In my own Silviphonic interventions that were developed during the recording of Millionth Acre2015discussed in detail below, wind provided the crucial input across the various surfaces of branches, generating a frictional bowing transmitted through the conductive xylem and into recording probes drilled into the base of the pine. Considering the wind as a musical bowing force has implications for instruments beyond Aeolian harps, as friction idiophones also produce sound as a result of bowing and are a family of instruments including Triolins and Nail Violins. The most well-known of the friction idiophones is ironically the saw violin, an object crucial to woodworking and forestry but also put into the service of making music. The aforementioned Silviphones use the readymade musical functions of trees and the wind, adapting entire trees into idiophones bowed by the wind.

The Music of Trees: Aeolian Instruments 


Recording through trees attempts to configure a compatibility between recording equipment and the living tree timber with the view that, despite plantation pines being “natural” materials, the trees themselves are inherently subjected to processes designed to ensure the production of sawlogs. Rather than emphasizing the chasm between natural materials and technical end products, silviphonics approaches standing timber as possible live instruments that rely on the innate musical qualities of trees and wind. The music generated by wind through its effects on trees is examined both in instrument building and naturalist literature, and it relies on the interaction between trees and meteorology. As an animating force matching the scale of entire trees, wind is capable of activating the sonic properties of trees and even entire forests.  Aeolian instruments use wind to generate music, and Aeolian music is described as emanating from both the landscape as well as the instrument. Derived from Greek Mythology in which Aeolus is the ruler of the winds, the Aeolian harp is a string instrument played by the wind. With special significance to transcendental and romantic philosophy, the Aeolian harp allowed listeners to listen to the “sad and triumphant melodies of nature” (Bock 2008: 110). 


Of specific interest here is the Aeolian musicality observed in nature by listeners tuned into the audio of forests. The “sphere music” witnessed by Thoreau and the wider field of Aeolian music is discussed in depth by Kahn as musical systems operating at an earth-scale (Kahn 2013: 56). For Kahn, John Muir’s description of the Aeolian sounds of trees is both locative and musical, incompassing Muir’s ability to hear the difference between tree species and speaking to a kind of Aeolian music generated entirely by the spatial configuration of forests, which Muir was supposedly capable of using as a navigational tool (Kahn 2013: 59). Another account of the music of trees involves an Aeolian harp described by romantic composer Hector Berlioz in a configuration where the harp was mounted in a tree: 


On one of those sombre days which sadden the close of the year, read Ossian and listen to the fantastic harmony of an Aeolian Harp hung at the top of a tree stripped of its leaves, and I defy you not the experience a deep feeling of sadness, of surrender, a vague and boundless yearning for another existence, an immense loathing for this one; in a word, a sharp attack of spleen link to a temptation toward suicide. (Hankins and Silverman 1995: 99)


Berlioz’s arrangement describes an intentional interfacing between botany and Aeolian instruments and, although simple, the possible sound generated by Berlioz’s harp relies on an atmosphere, imagined or otherwise, where a cold winter’s day generates comparatively somber tones.


Instrument building practices use the input of the wind and its interaction with trees as an additional avenue for hearing the Aeolian music of trees. For instrument builder Ros Bandt, Aeolian instruments are based not only on the Strouhal number (Bandt 2003: 195), which animates harp strings, but also objects that display an Aeolian character, including trees. The modified violin by Australian instrument builder John Rose – the Aeolian Double Necked Violin (1981) – interfaces between the Aeolian tones of trees and Aeolian instruments. Rose’s violin initially resembles Berlioz’s arrangement of an Aeolian harp hanging in a tree, with documentation of Rose’s instrument picturing the violin suspended between trees near Hawkesbury River in New South Wales (Rose 2007). Rather than relying on the wind to bow the strings, Rose engineered the instrument to catch the wind with a small sail that caused the instrument to “resonate in sympathy with the larger instrument structure” (Priest 2008: 186). In elaborating on forms of typically Australian-found Aeolian music, Bandt mentions the Casuarina tree species native as producing Aeolian tones. The music of the Casuarinaceae species is based on the long needle-like scales that grow in whorls and catch the breeze, producing a roaring sound like pine trees. 


The specific appreciation of the tones produced by vibrating pine needles is known as Matsukaze,or “song of the pines.” Violinist Shinichi Suzuki details how pines produce this musical note, explaining: “A rapid succession of small vortices are alternatively formed and detached from the rear sides of each pine needle, causing pressure perturbations to be imparted to the ambient air and heard as a musical note” (Suzuki 1958: 20). For Suzuki the musical aspects of pines operate according to the same principals as an Aeolian harp. Calculating the phenomena, Suzuki predicted the Strouhal number of pine needles, measuring the average diameter of the needle and the average velocity of the sea breeze of western Japan as three meters per second. The result of Suzuki’s calculation returned four hundred cycles per second, a pitch similar to the A string of a violin (Suzuki 1958: 21). 

Recording Agroforestry, Radiata Pine and Millionth Acre 


Drawing upon the xylophonic tree recording mentioned by Martin Michener and the acoustic testing being carried out in Australian radiata pine plantations, my recording experiments Millionth Acre (2015-2017) and Dark Corner (2016) are based ontaking recordings from pines in radiata pine plantations.Millionth Acredocuments the millionth acre of radiata pine planted in the Central Tablelands of New South Wales in 1972. The site features a small roadside plaque commemorating the expansion of the timber industry, yet when I first visited the site in 2012, the site had been clear-felled. Instead of thick pines, the land was blackened by burn piles and shriveled native plants poisoned by herbicide. Subsequent site visits aimed at field recording this zone of desolation, documenting a barren windswept plain where the forest previously stood. Ongoing documentation of the Millionth Acre site has been undertaken with two iterative installations, featuring  field recordings taken through pine trees, alongside documentary drone footage taken in Hampton State Forest. Dark Corner focused on taking recordings through individual trees along fire trails and minor access roads in a documentation of the New South Wales logging town Dark Corner. 


The Silviphonic recordings I made in agro-industrial forests were undertaken with a concern for trees beyond their use value simply as timber products. The recordings captured the woodborne sounds of pine needles and branches, moved by winds and transmitted through tree timber. Field recordings document the wind effects across clusters of needles and the collisions of minor branches, which caused sharper twangs, like the resonant twanging of fencing wire. The recordings from installation Millionth Acre featured durational audio, for which compact field recorders were used to document the movement of wind across the various surfaces of a pine. These recordings spanned almost a full day in mid-winter and document the windy, barren hills above Hampton State Forest. The interaction of wind with the different surfaces of the pines reveals the aerodynamic behaviors of trees, from the sweeping of needles to the resonant bounce of branches.

Pine forest devastation after clear-felling in Dark Corner, New South Wales. 

My documentation of these mass planted forests returns to the origins of silviculture, which developed from John Evelyn’s Silva, written in 1729. While Evelyn’s text was intended to be read as a forestry manual, he used the Silvato nominate trees of “greatest use, and the fittest to be cultivated” as well as advocate for conservation of culturally significant trees and sacred groves (Evelyn 1729: 2). Although Evelyn was personally engaged with forestry operations, Silva is littered with poetic anecdotes, including accounts of leafy groves by Petrarch and Virgil. However, the most evocative empathic relationship between human and tree is presented in Evelyn’s Silva with a passage from Lucan’s Pharsalia, speaking to a bodily connection between trees and the Roman soldiers set to remove the sacred grove. 


The Woods he bids them fell, not standing far 

From all their Work: Untouch'd in former War, 

Among the other bared Hill; it stands

Of a thick growth; the Soldiers valiant hands 

Trembled to strike, mov'd with the Majesty, 

And think the Axe from off the Sacred Tree 

Rebounding back, would their own Bodies wound. (Evelyn 1729: 312)


Evelyn’s personal fondness for trees and forests extended beyond increasing the cultivation of oak trees in British forests to a care and empathy for trees. Fabricating temporary silviphonic instruments during field recording visits to the Millionth Acre site became a way to listen to the high intensity agroforestry according to Evelyn’s empathic framework for cultivating trees and his veneration of forests. Despite his great admiration for forests, he was also engaged in forestry operations and goes to great length describing the correct execution of pruning and harvesting techniques. The history of silviculture is full of tree modification practices based on grooming trees into uniform products. 


The recordings made through pines in Million Acre and Dark Corner similarly involved modifications and drilling screws directly into trees. During the recording process, screws were fastened into standing pines to form a coupling of the conductive xylem of the pines; the exposed screw shafts protruding through the bark were mounted with piezoelectric disks that were connected to field recorders. This was undertaken as an adaptation of the friction idiophone, the family of instruments that includes Triolins and Nail Violins with wooden bodies and bowed metal pegs. As already mentioned, the most well-known of the friction idiophones is, ironically, the saw violin, an object crucial to woodworking and forestry but also put into the service of making music. The creation of silviphonic instruments involved forestry equipment and the acoustic qualities of standing timber in order to create tree-scaled friction idiophones. My adaptation of forestry power tools for recording tree sound employ common practices in silviculture, such as drilling. Cordless drills are commonly used for detecting internal cavities, employing sequential boring to ‘feel’ for hollows in tree (Ross 2015: 61). 


Forestry-specific modifications of radiata pine forests are widespread and include pruning the lower trunk sections of trees in order to generate straight sawlogs and increase the longitudinal structure of timber. This increases the similarity between living trees and their intended use for products such as boards. The recordings carried out for the project exploit the technical interventions of forestry in order to improve the conductive characteristics of trees for my own process of recording. As a conductive medium, the longitudinal modification of radiata pine to resemble straight logs makes them ideal for recording and adapting into instruments. In plantation pine forests the naturalness of the trees and incidental forest situations often conceals the inherent technical aspirations of silviculture. The large-scale site development and maintenance of the forests is undertaken ultimately with the aim of decreasing defects and variability and producing structural building materials. Whereas attempting to connect audio equipment to the pines highlights the material incompatibly between nature and recording equipment, evoking Caleb Kelly’s evaluation of the inherent material incompatibility between recording equipment and the places chosen as subject. Kelly writes: “field recording as a type of representation is always at odds with what it is representing. The tools and technologies used are far from any semblance of ‘nature’” (Kelly 2014: 9).

Millionth Acre (2017) found objects from Hampton state forest and audio recordings taken through radiata pine trees at the site of the millionth acre of pines planted in Oberon, New South Wales. 

The examination of the multiple sonic properties of trees, through the configuration of Silviphones, is based on a listening sensibility that treats trees as possessing a greater material significance than simply raw materials. Recording individual trees within state forests produces different tonal characteristics from tree to tree, yet despite their slight biological variations the pines are inherently destined to become sawlogs or pulp within the 30-year rotation cycles. The conversion of Australian native forest into plantations is an ecological inheritance that was fought fiercely by researcher and activist Richard Sylvan during the 1970s, however my recording works make no judgements regarding the persistence of this productive system but rather document the conditions found within agroforestry sites. The constant state of felling and planting provides an inherited system of land use in which eerily perfect forests are closely followed by clear-felling and utter destruction. The equipment of acoustic detection used in forestry grading became the basis for enabling a listening experience with forestry trees. While timber testing equipment such as the Sylvatest and Treetap employs sound for a diagnostic function, this process does not require any form of listening from the user or an audible output. Sylvaphonic recordings from living timber enables an aesthetic listening of forestry-grown radiata pine, akin to the matsukaze, offered by pines otherwise designated as insignificant crops or non-native intrusions. 



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