"Young She and the Grandmother Tree" is surely among the Children's Dance Theatre's prettiest shows. And it points up a number of lessons, not just shrilly espousing the cause of conservation but giving a fair shake to the many legitimate and beautiful uses for wood for which trees must be sacrificed.

The tone of this dance is gentle and rational, and its lesson, strong and clear, is that it's OK to use if we replenish, that finite resources must be recognized as such and replaced. Thus the final message is that death is not the real enemy if it leads naturally to the rebirth of life.A year's work for the dancers, teacher-choreographers and technical staff goes into CDT's spring show - not just dancing but staging, costumes and original music, and the effort always pays off in the smoothness of the final product.

It's interesting to track the progress of dancers up through the CDT training, which is not based on learning a lot of tight muscular control or intricate, tricky steps but on absorbing a free-flowing style of movement that can express the feelings and meaning of life.

You can see the CDT impulse surging through the various age groups. Thus the first embryonic efforts to swoop, glide, whirl and let the arms flow become more controlled and meaningful as the years go by, finally resulting in teenage dancers who move freely, quickly and gracefully - dancers who have the CDT impress of self-confidence and poise, with the power of expressive movement.

The script for "Young She" is by James Gallegos and Mary Ann Lee - a gentle, simple story in which Nancy Borgenicht narrates for the nurturing and beloved Grandmother Tree.

The original musical score by Julie Mark and Maggie Beers, using an interesting mix of synthetic keyboards, strings and flute with percussion, beautifully reinforces the message, often breaking into jigs or other tunes that have an Irish or nordic folk feeling - a feeling that Bruce Heltman's evocative forest backdrop reinforces. Nicholas Cavallaro provides the skillful lighting design.

Friday night's Youngest She was danced by Jennifer Webb, with Ashley Brooks as the older She who learns that sacrifice often leads to the greater good. Saturday's leads will be Jill Stewart and Samantha Snyder.

"Grandmother Tree" features hundreds of striking costumes on which no pains have been spared. Almost 20 volunteers worked more than 20 hours each to prepare the many costumes (not to mention the designing and nonstop sewing of Cynthia Turner and Nancy Cook, or the dozens who worked less time).

Among the prettiest are those for fairies in varied colors with gossamer wings, the flowing draperies with artistic dyeing for the many dancers representing the passage of the seasons, and pretty folk costumes for the maypole dancers.

There are gnomes in striped leotards, brightly colored leaves and crystals in white who manipulate tinsel stretch bands; and of course a bevy of young trees, in white shading to green, who hold up small branches to bespeak the hope for a new forest after Grandmother Tree gives her wood for man's uses, and her seeds for replanting. These costumes are among the most labor intensive in town and the most lovingly crafted, and as usual they are beautiful.

Opening the program is Jacque Lynn Bell's "Shout," which is a prayer for peace, a dream for peace and a shout for peace.

It opens with dancers in a series of supplicating vignettes and follows with dreamlike movement set to a lovely duet from Delibes' "Lakme." Then there's a stageful of kids in rocking rhythm, providing an appropriate closeout for a short and victorious war.