The paintings, of course, are flat. But they seem to have depth, are indeed designed to invite you into them. As Welliver has admitted (or defiantly asserted), speaking particularly about the scale of some of his work, he is “trying to seduce a person into really feeling that he can walk into your canvas.”

But then there is the further complication that his paintings are of Maine landscape, where, as he has remarked, “there is extraordinary clarity. You can look for a mile but objects seem right before your face; you can identify them. I’m interested in the character of the light -- that northern flat light -- were the sun doesn’t get very high.”

That paradox -- of distance in that kind of light and of depth and flatness in the painting -- is only one of an intricate set of ambiguities and enrichments by which Welliver’s paintings not only make their strong first impression but remain vivid, speaking to us engagingly over time so that one begins to think that duration serves an analogue for that third dimension that is not quite an illusion. The desolation of some of his dead trees is not sad but only an interesting moment in nature’s series of rough transactions, just as the riot of color of some of his recent studies of foliage is all the more dramatic because of our knowledge of the desolation that must inevitably follow. He has done some paintings of Moose Horn, for instance, that look to an urban eye to be representations of ruin and despair, but the water-logged terrain and the dead trees are the result of the work of beavers that dammed a stream which killed a part of the forest. In the long run, the impact on the ecology will be beneficial -- as Welliver expects us to understand. He is sympathetic but never sentimental, and what we come to realize is that his clarities of draftsmanship and palette are eerily necessary correlatives of a spiritual honesty, which he demands of us, too.

We have been warned about the excesses of Romanticism and, in particular, the dangers of the pathetic fallacy -- in which cold or stormy weather is supposed to stand for gloomy internal moods. But a level of sophistication that is altogether insusceptible to such blandishments would be a deformity, a disconnection from life and the ability to participate in the natural world. Those burnt stretches of woods in Welliver’s paintings of the early nineties with their oppressive foregrounds of browns and ochres and their glimpses of green or blue in the distance were, at first encounter, heartbreaking, even though we could tell ourselves how fire is a part of life and a necessary part of the life of the woods. We see now the same range of color, the browns and blacks close up and the relenting delicate greens and pale sky-blues in the distance in “Blueberry Burn Morey’s Hill.” The cleft of the peaks in that painting is frankly sexual, and, even while knowing better, we cannot help responding.

Nature, in Welliver’s work, turns out to be a shimmer of otherness: in that flat Maine light he likes, he invites us to peer in as clear-eyed a way as possible through an intricate cultural dazzle. These rustic scenes of his are pastorals, then, Eclogues that derive at least some of their power from our yearning for something more immediate and long-lasting than the mechanization and artifice in which we live and among which the finished works are themselves likely to hang. He paints his studies in plein air but then revises and expands these works back in the studio where he is altogether craftsmanly and theoretical. His way of working, in swaths across his large canvases from top to bottom, is that of the Douanier Rousseau, at the same time methodical and fantastic. The mark his paintbrush leaves is never merely that but allusive, a reaching out to an Arcadian idea, which, as we come to realize, insists upon itself as an idea. Welliver studied with Josef Albers, whose severe paintings are mostly experiments in different colors of squares, but it is the Hudson River painters whose lush and almost theological landscapes Welliver has called “procedural, systematic, structured, controlled, and prefabricated.”

We are invited to look at what is before us, but are required to look hard, for there are intimations and suggestions of things that may not be within the frame of the painting. A shadow of an overarching tree may make itself known if we look at the ripple of the brook in which the trout swims. The border of the water in “Sand Pool” suggests at first a flying buttress arching boldly across the field of the painting, but after we have resolved that impossibility by recomposing to the gentler image that is there, we find that the energy of the soaring remains and continues to charge our vision.

Those somber rocks he loves to paint -- we see them in “Blueberry Burn Morey’s Hill,” and “West from Morey’s Hill” as well as in “Aqua Spring” -- are conventional icons of perdurability and constancy, but of course they are changing all the time with every modulation of light and season. Because they suggest weight, they can give compositional heft to the pictures, anchoring the very ground that falls away to the left in “Aqua Spring.” But they can surprise us, too, and even allow an upward motion, as the eye of the beholder bounds higher from rock to rock as in the 1976 “Cedar Breaks” (Pennsylvania Academy of the Fine Arts).

Welliver’s stolid rocks assert what his still or flowing water modifies or clarifies in a conversation of contrarieties. These rocks, as we come to realize, are not inert but vivid and numinous, phenomenally aspiring to mortality and fleshliness. They make their suggestions even more clearly when we look back over the body of Welliver’s work to earlier paintings in which he posed voluptuous nudes in the woods. Those nudes no longer appear, because they don’t have to. To those who know, they are never altogether absent.

Neither is Neil Welliver. As his friend, the poet Mark Strand has written with characteristic acuity, “He will paint nothing else. The woods are not only his, they are him. That wildness, those turbulent waters, those trees and rock-strewn hilltops -- they are the images by which Welliver chooses to be seen and through which he sees himself. They occur again and again because they are the means by which his existence is affirmed. . . . a virtual sufficiency of self.”

And there is even more that the paintings say, because they are a medium of that curious relationship that the artist contrives with different degrees of intimacy for the different circles of his audience. This, it seems to me, is one of the increasingly important mysteries of art in our time. All those crowds that parade by the big shows of Monet or Van Gogh, or Matisse, with their audio tours and their gift shop souvenirs are troublesome, not hostile but not the artists’ friend, either. Museums may put an artist’s work on display to large numbers, but how many are really looking, and how many of them really see? More to the point, how does the artist find a way to speak differently and privately to those who are his true friends?

A painting you love and live with opens up to you. No matter where it may hang, you may come to own it, as it owns you. It repays with interest what interest and intelligence you bring to it, and what it teaches may take you some time to grow to learn. Bonnard’s work, for all its initially disarming appeal, is often quirky and demanding in that way. Welliver’s is, too.

-- David R. Slavitt

David R. Slavitt is a poet, translator, novelist, and critic whose recent books include PS3669.L3, Solomon Ibn Gabirol’s “A Crown for the King”, Three Amusements of Ausonius, and Joaõ Pinto Delgado’s “La Poema de la Reina Ester”. His new volume of fiction, Get Thee to a Nunnery: Two Shakespearean Divertimentos, will be published this month.