WE DON'T often, nowadays, have to worry about the vista through the trees on the other side of the lake.

A friend who has this glorious problem lives in a 150-year-old log house that has been added on to so that now it accommodates a wife, a good number of children and a couple of bull mastiffs, one of them pregnant. There's a terrace, edged with prostrate junipers and mugho pines, and a couple of hundred feet beyond is the pond, maybe 10 acres, and beyond it a stretch of meadow and beyond that a thick line of trees.

At one point the trees have been opened up, allowing a 40-foot-wide view to the fields and violet hills beyond.

The question in my friend's mind is how to thicken and enrich the far side of the pond, to make it more interesting in winter, but also to enhance the vista across the water and through the trees.

At one side of the opening a couple of elms have died and will be removed. Well to the left side is a fine old ash, which will of course be saved, and well to the right is a clump of fairly mature yellow poplars.

The other trees are rather a hedgerow, all grown together and pleasant enough to look at but without any special focus or interest.

On each side of the vista opening, he thought it would be a good idea to frame it with conifers, with cedars. Cedrus deodara and C. atlantica glauca are the ones he has chosen. I admired the knee-high trees in cans. He is a patient man, fortunately, since it will be some decades before they make their tremendous tabulated masses. If he is wise, he will plant them 25 feet to the side of the vista opening, since they are forest trees.

I took the liberty of suggesting a few other things:

Back of these cedars I would plant clumps of the Leyland cypress (Cupressocyparis leylandii), which can increase in height two or three feet a year. The first 10 years, the cedars will look like minor bushes in front of the upright cypresses, but in 20 or 30 years the cedars will become dominant.

If the place were mine, I would add a few native redcedar (Juniperus virginia) to the existing trees. This juniper, which grows wild all over that part of Virginia, is as beautiful as any confier can well be. My friend's wife is not sure she likes it.

Nonsense. No other conifer will add weight to the bare trees as well as that juniper, which keeps an exceptional beauty at all seasons and which is glorious to see at any age during its life.

He is very lucky the woodland trees do not come right to the lake, but that a space of 150 or 200 feet of meadow or pasture is at the lake edge.

At the left edge of the lake, he might try three golden willows and a clump of bald cypress.

To the extreme right of the lake, he might have a clump of sycamores and sweet gums. A little closer -- moving to the center from both sides -- I would try clumps of sour gums on both sides. At the water's edge.

I would guard against planting right up to the edge of the lake in general, however, keeping the meadow fore-ground to a large extent.

In that meadow, however, especially at the two sides farthest from the center, I would indulge myself with American hollies, inkberries, the hybrid hollies 'Fosteri No. 2' and 'Nellie R. Stevens.'

After those framing blocks and rounded masses of green, I would try a few treasures like sourwood, dogwood, some of the smaller Asian mountain ashes, the white Magnolia denudata, a Virginia fringe (Chionanthus virginica), some amelanchiers and choke cherries and the Asian Euonymus alatus.

If I thought things were getting too heavy or monumental looking, I would plant the elegant (though rather conspicuous) form of our wild locust called 'Frisia' with yellowish leaves.

A clump of witch hazels ('Orange Beauty') could be allowed near enough the lake edge to reflect in it with orange and mahogany viels in late winter.

Maples are a question. I would not want anything like the red-leaf Japanese maples, but some of the small green sorts of Acer palmatum, with due attention to the fall coloring of their leaves (for they vary a lot) might be included.

I would not hesitate to use the great 14-foot grass, Arundo donax, in one tremen-dous clump maybe 12 feet thick, and the variegated Chinese miscanthus might come in well near the lake edge several hundred feet away from the arundo.

A gunnera or the giant-leaf Petasites japonicus, could go near the bald cypress at the water.

As you view the far side of the lake from the house terrace you are looking north. From left to right the distance is maybe 1,500 feet, with the vista through the trees set more or less in the center.

I would thicken the extreme left and right points, then, with the plants mentioned, getting thinner and lighter toward the center. I would leave the plain meadow grass of the center, so that nothing is in the way of the tremendous cedars (as they someday will be) from the lake -- I would not like to see a gang of dogwoods and other small fry there.

Nothing would prevent me, either, from planting a little ivy on some of the hedgerow-type trees, and an occasional mantle of the Asian clematis that blooms around Labor Day, and the Virginia creeper up one or two of the yellow poplars.

I would persuade the Carolina jasmine to get busy on some of the smaller and less important shrubs, not only because of its winter greenery but its scented yellow flowers in April.

I might even try a couple of 50-foot-long beds of azalea just to the side of the central cedars and coming partly in front of them. Not a formal bed but shaped something like a whale, and I might well plant both of them solid with 'Stewartstonian,' a smoldering red azalea that has bronzy red leaves in winter. I know very well I would not plant mixed azaleas in such a place.

In suburban or town gardens, where space is so limited, the clotted pinks, whites, roses, magentas, scarlets and purples of azaleas do not bother me at all, but I would think them trifling in agreat landscape across the lake. There I would not hesitate to use something as flashy as scarlet, but I would have plenty of it in the two great azalea drifts, and then be done with it; resisting the temptation to plant this and that azalea elsewhere.

The grouping of the plants would be, of course, critical.

If choke cherries are used, say, that does not mean one every 20 feet along the way, but maybe five in one big clump. Once.

There are several danger points for the gardener in such a project:

Any gardener is going to want to try out all the big plants he ever heard of along the lake. And if he does, he will wind up with a dull fringe of sticks, when viewed from the house terrace. Nothing could be worse than trying out all the button-bushes, reed-maces, bam-boos, etc., up to the lake itself.

A similar danger arises in treating the meadow that now lies between the lake and the row of trees in the distance. There are several hundred variations among Japanese maples alone, and any gardener is going to have one or two waves of passion at the thought that now, by God, I can have a pretty complete collection.

He will get over it.

The lust towards libocedrus and parrotias -- which the gardener has seen at some great garden or other -- can be got over in time.

Of course if the gardener is sure they will do, under his conditions, there is no reason not to have them.

But our dogwoods are, when you look as long as three seconds, far more noble plants than any Japanese maple. The dogwoods, amelancheirs, aronias, sweet and sour gums, sourwoods, persimmons, are simply not to be surpassed for fall color, and our native hollies (though you notice I suggest a Chinese-English hybrid, for I am no snob) and our native redcedar juniper are as good for winter green as anything.

A further danger is wanting one of everything: Even after the itch for 279 kinds of Japanese maples has been alleviated, the gardener is going to want one each of several sorts of horse chestnut, 12 kinds of willow, the 29 best oaks, etc., and then he is going to fall in love with one plant more than the others, and is going to think of planting it from one end of the lake to the other.

Seeing how handsome the golden willows are, or how marvelous the sourwoods are at all seasons, why not put some on the other side to balance them?

And a few in between? To keep the continuity going?

No. The sourwoods go here. They would look just as well over there, too, but they aren't going over there. One mini-grove of sourwoods. And then no more, not anywhere and not ever.

All the things that are left over -- what? no persimmons? no barberries? no magnolias? no andromedas? -- or left out, can go elsewhere on the farm. Or, if one cannot live without barberries, then work them in, but leave other things out.

There is nothing magical about the plants to be selected.

There is something magical indeed in massing them (I do not like the word "Massing," it suggests they are jammed in) so they show off their best qualities and enhance their neighbors. Nothing should stick out like a sore thumb. Except, I suppose, the cedars. All the rest must give richness, depth, variety, tone, overtone and so forth. Not stop the show.

Let me say that a day with a friend worried about the lake vista does little to cheer a fellow on his 40-foot city lot. And yet it is the same excitement, the same difficulty, the same triumph either place.