Woodland Heights is a study of forest canopy ecology. More specifically, the work is an illustration of the premise that “species composition and tree size distributions become more diverse with increasing stand age” and that “with increasing age stochastic processes play increasingly important roles in creating structural complexity” ¹.


The form of the piece maps the growth of a model forest stand over a projected 720-year period, where a crotchet in the score is equal to a year in ecological time. The structure is divided into three successionary periods demarcated by radical change in accordance with the principle that “local disturbances not only maintain the character of the system by maintaining the species that are early colonists but poor competitors; they also maintain the resiliency of the system, preserving the opportunistic species that thrive under the conditions accompanying the unpredictable but inevitable environmental changes that occur at broader spatial scales, such as windthrows or fire.” ²


The imagined forest is composed of seven tree species common to the garden of my original family home in Chorleywood, from which the piece also takes its title. The first two sections map the projected interactions of six species: Silver Birch (Betula pendula), Laurel (Prunus laurocerasus), Holly (Ilex aquifolium), Rowan (Sorbus rosaceae), Beech (Fagus sylvatica) and Oak (Quercus robur) which take their roots from E, A, D, C#, G and C respectively. In the third section, the viola solo introduces the seventh species: Wild Apple (Malus sylvatica) on Bb.


Particular qualities of each species type are translated into musical elements in the score: maximum height, average lifespan and reproductive cycles are expressed through the statistical distribution of the overtone series from the open strings fundamentals of the orchestra, the adaptational qualities of a species by its role in the formal development of the piece and its phyllotaxis by motivical structure.


Writing this piece necessitated an exploration of the fascinating terrain that is contemporary ecology and provided a reassurance that humanity’s deep love of the biosphere still finds expression in our societal priorities. Today’s ecologists have embedded conservational and educational elements deep into their discipline and together form a large and extremely open network of individuals working across the world to better understand and preserve the immense diversity found on planet Earth. In the words of two of canopy ecology’s pioneers: “Perhaps that is the ultimate goal of canopy research – all scientific research for that matter – to produce a sense of the vast and the infinite and to promote our sense of wonder, a curiosity that needs to be fed by experience to be long-lived.” ³


It requires very little rephrasing of this idea to appreciate that the beauty of this statement could be applied equally to the objective of the artist. In composing this work I have come to appreciate the enormous translatative power of music and the many vantage points that it offers us for immersion and enquiry into its sources of inspiration and have also come to understand that the web-like creational processes of investigation, experimentation, epiphany and revision share many commonalities across the Sciences and the Arts. Numerous great minds throughout human history have proved a constant reminder that in reality there is no separation between these two great fields of discipline, and that just as two hands work together in playing an instrument, so these two aspects of human nature form part of a single integrated response to the questions of our environment.


In creating both new work and new theories, we must exercise great freedom in our relationship to a subject matter in order to allow scope for intuitive processes to develop. Similarly we must give free reign to the imagination in order to find connections between ideas and to build structures that can later become material for further development. Perhaps in the future we will understand more about how the imagination works and its evolutionary development, but for now we must be content with understanding that without freedom and diversity there can be no development. The same lesson taught in fact, by forest canopy ecologists with regard to species biodiversity. It is no coincidence that every great work of both art and science contains some unanswered and perhaps unanswerable question buried within itself, and it is this that I believe inspires that ‘sense of wonder’ and imbues it with a complexity that is a microcosm of the depth found in life itself. A work that is the result of a logical or mechanical process alone risks becoming lifeless and predictable – in art, as in life, rules are made to be broken. Our greatest priority at this moment in the history of our planet should be to conserve and protect the spectral magnificence of life in all of its many forms, preserving and protecting the unknown as well as the known will provide a future for our planet and its wealth of expression in form.


I am greatly indebted to numerous individuals who assisted in the creation of this work. In particular I would like to thank Dr. Thomas E. Lovejoy, Dr. Margaret D. Lowman, Dr. Simon Levin, Dr. Henry S. Horn, Dr. Michael Jones, Sven P. Batke and Noel O’Shea for their scientific and technical expertise; Katherine Hunka, Robin Panter, Malachy Robinson, Cora Venus Lunny, Adrian Hart, Olesya Zdorovetska, Francesco Turrisi, Linda Bsiri, Sachiko Kuriowa, Ellen Fallowfield, Kate Ellis and Russell Rolen for their musical counsel; Sheila Pratschke and Nora Hickey M’Sichili together with all of the staff at the Centre Culturel Irlandais, Paris for the amazing opportunity to work on this piece in such creatively fertile surroundings and finally a special thanks to artist Ruth O’Donnell for providing the beautiful illustrations for the score.


This piece is dedicated to the trees of ‘Woodland Heights’, Greenhills Close, Chorleywood – to the laurel, oak, birch, rowan, beech, holly…and the wild apple.



¹ Hiroaki T. Ishii, Robert Van Pelt, Geoffrey G. Parker, Nalini M. Nadkarni (2004). Age-Related Development of Canopy Structure and Its Ecological Functions. Forest Canopies, Second Edition.

² Simon Levin (1999). Ecological Assembly. Fragile Dominion.

³ Margaret D. Lowman and H. Bruce Rinker (2004). Introduction. Forest Canopies, Second Edition.


†  String harmonics image on glossary p.1 taken from, reprinted with permission of author.


first 13 harmonics clearer

Flocking III

Performance Notes

Flocking III explores the mechanisms of the emergent system, in which individual components can be perceived to express themselves as a group. Nature offers many spectacular examples of this type of behaviour, of which perhaps the most beautiful is the flocking of birds in flight.

Of all the birds found in this world, the starling flock is considered to be the most impressive in terms of number and reaction time, and so perhaps for this reason it is given the most beautiful of names – a murmuration. Starling murmurations are also the subject of the most scientific research for these very same reasons; flocks can number greater than 100,000 individual birds and their reaction time whilst in flight as little as 0.026 seconds.

My work on the Flocking Series was informed by the research of computer scientist Dr. Pavlos Antoniou of the University of Cyprus and mathematical biologists Luke Coburn and Dr. Iain Couzin of CouzinLabs in Princeton University. As source material for Flocking I-II, data derived from bird flocking simulators (or boids) and their x,y and z co-ordinates in space was translated in musical values of pitch, attack frequency and dynamic. The streams of numbers yielded behavioural types that emulated the movements of birds in the air and in places the score itself bore resemblance to flock patterns and the motion of the wing.

Flocking III is a new type of score, based on the realisation that humans also display behavioural patterns and can express themselves as a group. In fact we do this every day of our lives, whether walking in a crowd or listening and responding in the language of music.

The grammatical structure of music is formed of basic variables, just as a spoken language is self-organised, and these emergent properties can be translated into action through improvisation. This process is actually how we learn to play music in a large group, as was traditionally found in human societies throughout history and continues simultaneously today in many parts of the world.

Performance of the piece requires each member of the ensemble to listen and reach to three variables in the music. These areas are defined as ZoR, ZoO and ZoA and correspond to the zones of Repulsion, Orientation and Attraction, which are used to translate the motions of flock mechanics into simulations. These areas govern the behaviour of the individual bird; when another bird moves into the zone of Repulsion the instinctual response is to move away, and similarly to align or move towards in the zones of Orientation and Attraction.



The zone of Attraction (ZoA) takes pitch as its variable. The performer should graduate the pitch or pitches that they are playing according to the sounds that they hear around them, always moving towards the notes that they perceive. 

The transition to move from ZoA into the next zone occurs when all of the performers play a single unison pitch (or its octaves).


The zone of Orientation (ZoO) takes attack as its variable. The performer should adjust the frequency of attack of the gestures that they are playing according to the frequencies of the rhythmic attacks that they hear around them, always trying to align with these frequencies.

The transition to move from ZoO into the next zone occurs when all of the performers play in rhythmic unison (or in metered polyrhythm). 


The zone of Repulsion (ZoR) takes dynamic as its variable. The performer should emulate the dynamic of the performers around them, but also is encouraged to break the rules of this zone and to improvise freely if they feel so inclined.

The transition to move from ZoR into the next zone occurs when all of the performers are playing at a minimum dynamic using breath sounds.

The final structural element of the composition is the introduction of the predator to the group flock dynamic. In a large ensemble, one of the performers should be assigned this soloistic role and either do not participate in the performance with the rest of the group, or leave the flock after a certain number of completed cycles. This performer is then freed to periodically interject with varying dynamic gestures using multiphonics solely. Upon hearing the interjections of the predator, the other performers making up the flock should continue to obey the rules of the particular zone in which they find themselves, but also employ solely multiphonic gestures.

The spatial positions of the performers and the speed of their responses will govern the behavioural characteristics of the sonic flocking effect. Experimentation is invited with this element of the performance, with relation to both the positioning or mobility of the flock and the predator. The default position of the ensemble is a semi-circle with instruments ordered according to pitch range from stage left to right.

Flocking III may begin in any one of the three zones, and the transitional points can lead to either of the two remaining zones. These structural decisions may however be predetermined, in which case the default movement should be ZoA – ZoO – ZoR and continue in a cyclical form. Other predetermined variations may also be developed once the ensemble has performed this initial formal structure. The structure of the work may also, and preferably, by determined in real-time by the improvised responses by the members of the ensemble to the rules for each zone and their transitional movements. 

It is worth noting that whilst in a particular zone it will prove beneficial to focus primarily on the musical variable that governs this temporal area, even to the extent of limiting the degree of variance in the other two variables employed at other times during the piece.



[1] Pavlos Antoniou, Andreas Pitsillides, Tim Blackwell, Andries Engelbrecht, and Loizos Michael, “Congestion control in wireless sensor networks based on bird flocking behavior,” Elsevier Computer Networks Journal, vol. 57, no. 5, pp. 1167-1191, April 2013. [pdf]