Germaine Greer, who did ?¨so much for feminism, has ?¨got herself a new cause: gardening. But it's gardening on a grand scale. Weeding for her is removing acres of lantana and kangaroo vine. Planting involves tending 150 white beech saplings that will grow into trees 40 metres (131ft) high. Instead of slugs, she has got ?¨tics and leeches. For Greer decided ?¨12 years ago to restore 60 hectares of Mesozoic 'Gondwanan' rainforest, called Cave Creek, near the Eastern tip of Queensland.

From the moment settlers arrived in Australia, they seem to have devoted themselves to obliterating everything that lived. To see a tree was to cut ?¨it down. They passed 15 different Marsupial Destruction Acts. They willingly doused their own land with Agent Orange, and consistently attacked not just ancient societies and ecosystems, but such startlingly marvellous things as koalas, gliders, Wonga Wonga pigeons, pademelons and glow-worms. How could they look at all this stuff and just think, "Kill"?

Becoming a conservationist was ?¨not the plan. Greer was originally searching for a house in Australia in which to store her vast archive. But she came upon a rundown dairy farm and was smitten, thanks to a bower bird: "I needed a sign and the bird was it … an ambassador from the realm of biodiversity, which is every earthling's birthright." Earthling! Is she writing from Mars? The archive is never mentioned again (it's recently been purchased by Melbourne University).

Having bought a place she knew nothing about, Greer embarks on knowing more about it than anyone else. The result is a book that ranges from natural history and botany ?¨("The Australian tamarinds belong to the sapindaceous genus Diploglottis, whereas the historic Tamarind … is fabaceous") to genealogy, technical info and practical advice, at times matey, polemical and mystical. But it is no Moby Dick.

There are too many long, improbable conversations as Greer and her sister, or other pals, sort out abstruse botanical conundrums, most of which could have been handled more simply and elegantly in prose form.

"'How old would you say they are?'

'They grow slowly. Twenty years, mebbe?'" Etc, etc.

Repetitive and meandering, Greer's material begs to be organised, compressed and synthesized into ?¨a coherent structure. You never know what is going on. She gives us an impressive litany of Australian errors social, botanical and biological, is wonderfully scathing about their genocidal treatment of animals, and her description of the timber industry makes rightly painful reading. Her excitement about the flora and fauna she encounters too is contagious. But the book is as tangled as one of Greer's strangling figs that squeeze the life out of the host tree (or, in this case, the reader).

My concern is not so much aesthetic as ecological: that White Beech's peculiar construction may distract attention from an admirable project. Reading it, you feel like you are tagging along behind Greer on an arduous expedition, wondering if she even knows you are there. Her 20-page disquisition on the macadamia genus nearly killed me:

"'Funny isn't it?' said I to Jenny. ?¨'In Enzed you've got two genera of Proteaceae and both are monotypic, making a grand total of two species. Mind you, there are many monotypic genera in the family. Out of 42 genera in Oz 16 or 17 have only one species. Isn't it odd that New Zealand, only 2000 kilometres or so off the coast of Australia should have only two proteaceous species when Australia has more than 850?'"

It's not autobiography either. We find out nothing further about her life in Australia (where Greer now spends several months a year) except that she occasionally cracks open a bottle ?¨of wine and eats a salad, or makes black apple popsicles. At one point she flings a "sated" leech from her sock, leading to the perplexing statement: "Vital substance of mine was already incorporated in the Cave Creek biomass."

Greer writes best about her cherished trees, the slumbering snakes, or a Rufous Fantail whose "fanned brick-red tail is edged with ?¨a white so bright that it seems to leave tracks in the sunlit air". You get the feeling she is just too busy heaving tree trunks around with her male workforce (who have the nerve to find some of her ideas "girly") to sort the book itself out into a satisfactory organism, with its own shape and substance. The link between environmentalism and feminism, ?¨for instance, she almost wholly omits. But if Greer will not stress it, I will. Men have wrecked the world through greed, Oedipus complexes, an innate desire for destruction and lust for steak. "Darlings, what have you done, what have you done to the earth?" asks Carol Ann Duffy's The Woman In The Moon. Reversing this ruination, if it can be reversed, is a feminist issue.

Greer's project, in conjunction with some kindred conservation efforts, is contributing to a growing chain (now covering 3665 kms, 2300 miles) of prehistoric rainforest remnants across Australia, and beyond. It is an indubitable achievement and has given Greer, she says, "heart's ease" and a certain humility: "The tiny snail negotiating the edge of that lettuce leaf is my cousin." That's nice. The thing is, she now expects us all to do it! "The same opportunity is out there for everyone … You can stop mowing … let your quarter-acre revert to Moonah Woodland and Coast Banksia… [and] combine your backyards, to make ?¨a safe place … for echidnas to mosey about in." In Edinburgh? I only have ?¨a little iron balcony with a couple of empty flower pots on it. No sign of an echidna yet. Funny, isn't it?