There was a very brilliant but rather eccentric biologist in Montreal who was convinced -- or perhaps he just convinced us that he was convinced -- that the squirrels were not only watching him, but were stealing his secrets.

"Look at him," he'd say, pointing to a squirrel perched on the windowsill, "squirreling away information, the same way as he does with nuts. Store and retrieve when needed. Squirrels are going to take over the world, mark my words! They know mankind is doomed."

The scientist had a wonderful, nonsensical sense of humor (he was an avid fan of "The Goons" BBC radio show with Peter Sellers, Spike Milligan and a few other British zanies), but the squirrel thing did become a bit of an obsession. In the end he'd not allow his window to be opened unless he was in the room, and he always left his notebooks closed. His fellow scientists and assistants only encouraged this phobia by sneaking into his office and maintaining a regular supply of nuts on the windowsill.

These were gray squirrels (Sciurus carolinensis), originally native to the deciduous woodlands of eastern North America. This cheeky little animal becomes very accustomed to people, and in many parks and gardens with trees, gray squirrels will take food from your hand. In one park, I saw an old man tapping two large coins, the edge of one against the face of the other, making a noise that sounded like a squirrel's chitter. It brought gray squirrels right up to him, where he fed them peanuts.

The squirrel we have in our Afan Trust woods here in Kurohime, Nagano Prefecture -- as throughout most of Japan -- is the red squirrel (Sciurus vulgaris), known as risu in Japanese. This smaller animal ranges throughout temperate Eurasia, and until the 19th century it was the only tree squirrel found in my native Britain. There, it is usually an attractive reddish-brown, but the colors can vary. In northern Europe it is silvery gray, and in Switzerland black and white. In Japan, the ones I see regularly are grayish-brown. From the tip of its nose to the end of its bushy tail, it can grow to 30 cm.

The squirrel builds untidy-looking round dreys, or nests, of twigs and branches lined with moss, usually high up in the branches of a tree, but sometimes in hollows. It has two litters a year of three to seven young that are born blind, but become independent of their mother by the time they are two months old, and mature in one year.

The red squirrel in Britain has a preference for conifers, and loves pine seeds, but will eat beech mast, nuts, acorns, mushrooms and so on. After the gray squirrel was introduced to Britain, it largely displaced the red, and as a boy I was told that the grays would raid and kill the young reds. The gray squirrel is larger than the red, its body growing up to 30 cm long, with a tail almost as long again, and weighing in at up to 750 grams. It does not have the perky little ear tufts of red squirrels. My grandfather and foresters that I knew in Britain called the gray squirrels "tree rats."

When I was 19, I owned a long-barreled, single-shot, bolt-action, .22-caliber rifle. It was very accurate. As a lad I avidly read tales of the early American pioneers with their "squirrel guns" -- elegantly long-barreled, small-caliber, muzzle-loading rifles that used little powder and lead but were very accurate. I especially enjoyed reading about the War of Independence, when these woodsmen would hide behind trees, bushes and walls to snipe at redcoats armed with clumsy, inaccurate, smooth-bored muskets.

The pioneers hunted squirrels for their meat and their fur, and as Britain's Forestry Commission and private landowners not only encouraged the shooting of the grays, but at times even paid a bounty on the tails, I, too, shot them with my rifle -- and tried various ways of cooking them. This horrified my mother, so my cooking was usually outdoors, but honestly, stewed squirrel was quite good. I tanned the skins myself and made them into mittens to give to ladies, including my dear old mum -- who didn't seem to mind the death of the little animal once it was turned into warm, soft fur. I even made a little pocket money by selling gray squirrel mittens.

I was extremely careful where I aimed when I was shooting at gray squirrels in trees, always making sure there was a trunk or a thick branch behind them, for even a little .22 bullet can be harmful at over a kilometer. It never, ever entered my head to shoot at a little red squirrel, which was protected anyway.

Despite the activities of people like me, the grays spread and in Britain now you are only likely to see reds in isolated pockets in England, Wales and Scotland. A lot of foresters claim that both these squirrels do a lot of damage to trees, but I take that, like my gray squirrel stew, with a pinch of salt. These creatures' habit of burying acorns and nuts and then not always retrieving them results in the dispersal of such deciduous trees, because once planted and left alone, nuts and acorns are likely to grow.

Meanwhile, nitrogen-fixing bacteria in the tissues and spores of mycorrhizal fungi and yeast all interact and survive passage through the intestinal tracts of small forest mammals. In other words, not only do squirrels frequently eat mushrooms, but they also actively spread them and ensure their survival.

The unseen threads of fungi spreading throughout a healthy forest floor are crucial to the health of trees, especially pine, fir, spruce, larch, hemlock, oak, birch and alder, because they depend on exchange below ground between fungal hyphae ("threads") and tree rootlets. The fungus gets some simple sugars, which it can't make itself, and the tree receives an extension of its root system that is physiologically and geometrically effective in taking up nutrients and water.

In other words, more and more, we are coming to realize that animals like squirrels are essential living partners of the forest.

Before I get too technical, let me relate an incident. I was in a patch of woodland in Britain at night, watching badgers (at least, that's my story; I'll not admit to poaching!). As I sat very still under an oak tree, what I first thought were leaves came fluttering down, a couple at a time, every few minutes. Eventually some of these "leaves" landed at my feet and I looked at them. They were not leaves. They were moth wings. Looking up I saw a gray squirrel munching on a moth and dropping the wings. Moth caterpillars can strip a tree, so surely, that is another little illustration of how a squirrel does its bit, squirreling away for conservation and biodiversity.