Leaves were solar collectors. They generated sugars that flowed through the inner bark and changed into the wood material of the branches, trunk, and roots. The slide of stored light (each year recorded in growth rings) was how the tree increased in size – with an effect like a candle coating itself and growing fatter at the base.

From the bare gate a kilometre off a particular tree on the high sandy plateau resembled a child’s transfer. Scattered across the slope were others of the same species. Some showed brittle, skeletonised limbs and gappy, insect-eaten foliage. Others seemed to have been drawn with a snapped pencil. The light showed through all of them. As I drove closer the one tree thickened and spread, showing itself immense in the winter light. The way it played back and forth with scale, now puny, now enormous, was a conversation we had every time I drove the last kilometre. When I left the car the trunk rose sleek as marble, cold and weighted to the touch. Checking it over by feel, smoothing the bark, impressed by its elephant-like presence, I stepped back seeing what sticks had fallen while I was away (upper wood with a habit of loosing itself and crashing). There was a matting of twigs underfoot, a rain of firewood fallen among corkscrewed scrolls of bark and layered leaves. Out came a cardboard box and in moments enough kindling was gathered for the fire.

Inside the house the Warmray stove crackled with flame struck from the tree’s stored light.

There might be a sign over this to say ‘Poet at work’, in that the whole is rich in characteristic poetic resources. These include the organising of the account around a few cardinal notions (the storing of light, the incessancy of transformation, the constant disclosures), the confidence in analogy and imagery, the readiness to reiterate for illumination’s sake, the instinctive reaching for the rhythmic. McDonald’s writing, here as elsewhere, tends towards enchantment, as engrossment develops into celebration. The whole book is a ‘laudatio’, a song in praise of trees, a song all the more taking in that its maker has a hawk’s eye for the particular. That ‘candle coating itself and growing fatter at the base’, those trees which ‘seemed to have been drawn with a snapped pencil’, those ‘corkscrewed scrolls of bark’ – these things legitimate the elation which shows on every page.

But McDonald’s poem ‘Recent Archaeology’ ends with the words, ‘The suburban king and queen in their burial mound of waste / cry out as they never dared while living’, a note of ruefulness and compassion to be heard often in his writing. The Tree in Changing Light, too, makes ample room for that note. So, well into the book:

Visiting my friend in the spinal unit he asked me how many trees would grow on five acres. Lying there paralysed from the neck down, smiling and talking about trees, it didn’t matter to him for those few minutes that he was a ‘ventilated quad’ (what he remembered each morning when he woke – imagine it). The block was bare and maybe this was something he could do when at last they took him home, manage hundreds of trees into existence and oversee every aspect of their lives – olives, nuts, citrus. I pictured him on his five acres after his workmates built the house for him, getting around in an electric wheelchair on shaded paths damp with sprinkler throw.

George Herbert, guardedly unhappy, says in one poem, ‘I read, and sigh, and wish I were a tree’, and in another, ‘Oh that I were an Orange-tree, / That busie plant’, hoping not to be fruitless. McDonald’s way is more edged, and more angular. The trees he applauds are emphatically on the human horizon, including that horizon’s tragedies. It is one thing to be, abstractly, at home in a tree-filled world, and quite another to be of their company as a ventilated quad. The ‘changing light’ of the book’s title might apply to the many lights in which trees are seen, but also to the lights and darknesses in which its numerous characters find themselves.

Amongst those characters is the narrator himself: the book is veined through with autobiography, though it is altogether free of the imperfectly masked narcissism which taints so much autobiographical writing. Sometimes attention is on the immediate and the particular, as when he says, of dealing with wild tobacco, ‘I felt a fist clench in my chest every time I chopped’. And sometimes the reflective mind spans past and present, in a kind of Yeats-in-Australia reverie:

Family history as it expresses itself in an individual can feel like something coming from nowhere, because the roots are buried. It is only now, in midlife, that I feel this matter of trees as part of a line of continuation. My mind sinks back; I go into the shade; it feels like drawing water up through fine capillary veins and having leaves uncurl, and then those leaves hanging edge-on to the hard Australian sunlight. I like to think of the earth around the roots being kept damp by a sprinkler disgorging cold, silver water.

It is a mark of original minds, original imaginations, that they are not dictated to by someone else’s notion of how reality is to be sounded or sliced across: they may be avid for reading, but they will not take dictation. Sometimes, as in Juan Ramon Jimenez’s injunction, ‘If someone gives you lined paper, write the other way’, they may issue manifestos or retorts. McDonald is not usually one for that, but a passage like this one displays his characteristic sense that thought and feeling are Adamic: the great garden is all around, but one has to find all the names for it and its creatures by oneself.

It is only slightly paradoxical that The Tree in Changing Light is deeply indebted to a wide and various reading about its matter: Ruskin, Pasternak, Auden, Rilke, William Hart-Smith, Stevenson, and Judith Wright are only a few of those who have been laid under contribution. McDonald has made them his own: in the words of the first passage quoted here, they ‘generated sugars that flowed’ into the distinctive life and structure of his book. They, too, make for the book’s ‘stored light’.