Thought-provoking programming is one hallmark of the concerts music director David Zinman conducts here in Aspen. For the Sunday afternoon concert with the Aspen Festival Orchestra, he juxtaposed Richard Strauss' quiet, dignified lament for strings, Metamorphosen, with Gustav Mahler's considerably more boisterous Das Lied von der Erde, which ends with one of the most heart-rending good-byes in the concert literature.

Thoughtful listeners can find plenty to chew on after hearing worthy performances of these works Sunday in the Benedict Music Tent. Not least, to me, is the edginess and harmonic adventurousness of the sprawling Mahler work, written in 1911, coming after the conservative Romanticism of the Strauss, written more than a third of a century (and two world wars) later.

The Mahler piece is a collection of six songs based on poems translated from the Chinese into German -- all reflections on death -- set lavishly to music. It employs a tenor and a contralto (or mezzo soprano) and an outsized orchestra. To hear it preceded by the gentle sounds of Strauss' piece, written for a string orchestra of 23 musicians, only highlights the brashness and technicolor brilliance of the earlier, bigger work.

In his conducting, Zinman marked the difference even more strongly, keeping a tight rein during the Strauss. There could have been greater contrasts between phrases, more changes of tone and tempo to set the sections apart, but Zinman got none of that. Instead, he went for and achieved a sort of gentle arc and a unanimity of feeling. In a nice gesture, he walked through the orchestra shaking the hand of each musician individually after the gentle finish.

In contrast, Das Lied opens with jaunty horn call and a robust introduction from the full orchestra. Zinman drew lithe, responsive playing from the musicians, and among the many fine solo turns special mention should be made of Louis Ranger's sprightly trumpet filigrees in the first movement and Nadine Asin's flute quietly closing the first half of the heartbreaking finale.

The tenor gets the first song, Das Drinklied von Jammer der Erde ("The drinking song of Earth's sorrow"), and the two singers alternate thereafter. Much of the tenor's music lies in the high register and requires him to compete with some serious volume from the orchestra. In a solid, straightforward performance, Jon Villars, who sings a lot of the heroic roles in opera, never seemed to be straining but he didn't always get through the thick orchestration, either. Phrases that ended low often were inaudible.

Nancy Maultsby has a true contralto but she can also maneuver well in the higher reaches of the mezzo-soprano territory. The voice is seamless and strong, even if it isn't as colorful or loud as others. She was especially effective in he quieter moments, and delivered when it counted. In Abschied ("Farewell"), the final song and the longest and most thoroughly developed of the six movements (lasting about a half hour), she had the space to develop pathos and nobility. By the time Maultsby got to the final, fading repetitions of "ewig..." ("eternally") she and Zinman created exactly the sort of suspension in time that Mahler wanted.