THE MYSTERY OF THE LITTLE TREES

Here is an irresistible something in the plant kingdom that impels it to multiply and cover the land. In its abundant growth, husky members often predominate over the frail. Yet there are places where even the strong meet with defeat, the reason not always readily discernible. It was one of these mysteries that my husband, Moulton, and I came across one day in the Kaibab Forest on the North Rim of the Grand Canyon. A beautiful meadow lay before us, painted with colorful splashes of pink and white phlox. At a little pond in the lowland, a huge red-tailed hawk slaked his thirst, and a small herd of deer browsed leisurely nearby. Back of the meadow the North Kaibab forest of spruce and aspen towered against fleecy clouds that drifted across a vividly-blue sky. And then Moulton and I saw the curious display of little trees. From the forest down to the edge of the meadow, dozens of tiny spruce trees were scattered, like a flock of baby chicks whose eagerness had led them to a strange place across which they dared not pass. At the edge of the meadow their journey had been oddly and abruptly halted.

Long after we left the Kaibab Forest we pondered the botanical mystery. The memory of the little spruces kept nudging us; but it wasn't until two years later that we discussed them with a professional naturalist.

We learned that annual tree rings had been counted on six small trees at the North Kaibab meadows, and that the ones counted averaged ranged from 20 to 41 rings to the tree. Whether the count would be typical of all the little trees that is, of course, not known. A few of the little trees at the meadows' edges are Engelmann Spruce (Picea engelmanni). But the predominating species is Blue Spruce (Picea punguns). Blue Spruce, the naturalist told us, usually grows as a single isolated tree or as a single row of trees along the edges of the meadows and in other moist locations. Engelmann Spruce forms the dense stands and is the principal forest spruce of the Kaibab Plateau.

It is true that some small trees tend to grow at a slower rate than "adolescent" saplings. Their branches are more closely crowded which gives them a squat appearance. As they become taller, their growth seems to speed up and a slimming process takes place.

But on infant trees which we have observed, the foliage is more or less tender. On our little trees at the meadow, the foliage was not only dense, but thick, harsh and old-looking, as though their struggle to grow had been thwarted by some grim genie bent on disaster in the plant world.

Under normal conditions Blue Spruce will eventually attain a height of 80 to 100 feet. Engelmann Spruce will grow to 120 feet. The young spruce saplings on the slopes above the meadows we noted were slimming up and bore every evidence that they would reach normal height. The delicacy of their foliage and slimness of trunk showed them to be young trees. On the other hand, many of our little trees at the meadow's edge we believe bear evidence of some kind of growth hindrance.

Not all is known of the underground conditions of

the meadows. But it is known, the naturalist told us, that the meadows are inundated in the spring. Even after the heavy snows meit and surface waters have drained off, the water table may remain just below the surface for two or three weeks. The concentration of moisture creates a too-swampy condition for these species of trees. This is suggested as one reason that the little spruces do not advance into the meadows. "It is also probable," Moulton reasons, "that the overabundance of standing water has leached the plant food from the ground, thereby diminishing the nourishment for the little spruces which is necessary for normal growth. Should this be the case, the growth of the little trees would naturally be retarded." If there are adverse conditions aside from the flood waters under the surface of the meadows, they will one day be discovered, for scientists are constantly at work exploring the hidden recesses of the Grand Canyon area. The present-known culprit seems to be old man Weather, who creates thunder storms in summer and heavy snows in winter and pours their waters into the meadows. Numerous questions are asked each year by tourists about the little trees; one of the most common: "Were they planted there?" The answer, of course, is no, that they are seedlings which grew naturally. Public interest in trees has motivated many popular tree booklets. Grand Canyon Natural History Association a few years back published a booklet called, "Trees of Grand Canyon National Park," with text written by Natt N. Dodge. Indicating the climatic conditions which would deter the little trees from crossing the meadows, he describes one of the silent dramas of the plant world; the continuous "battle" between herbaceous plants, which attempt to invade the forests, and the trees' endeavor to forest the meadows. The delicate balance which holds the "battle line" depends upon climate. A change, though slight, over a sufficient period could upset the balance and swing the tide the other way. Probably for as long a time as you and I may visit the Kaibab Forest, we shall see the exploring little trees mysteriously halted at the meadow's edge-waiting for that "change in climate conditions" when possibly their descendants may be able to venture across the land and pioneer a new evergreen forest.