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October 1932Volume 7, Number 7


IN EARLY three years ago a crown fire destroyed about eighty acres of pinyon-juniper forest in the vicinity of Yaki Point, about four miles east of Grand Canyon Village. Since the production of such a forest results only from a long process of plant succession it will be many years, probably more than two hundred and fifty, before a similar forest will again occupy this region.

In the meantime a great many plants will come and go on this site, as new species migrate to it, and many of them are eliminated by the vigorous competition that will result.

It is very noticeable that the dominant plants on the area at the present time are species which grew in a suppressed condition on the forest floor before the burn occurred. The reason for this is not difficult to explain, A forest of the pinyon-juniper type produces only small amounts of litter and combustible organic matter on the forest floor. This is due principally to the type of tree, the open stand, and the slow growth.

Consequently, a ground fire which burns deep into an organic soil destroying all living roots, rarely occurs in a pinyon-juniper forest. The crown fire which destroyed this stand no doubt killed every trace of growth above ground, but left the roots of the shrubs and herbs, which grew in a suppressed condition under the dominant trees before the fire, undamaged by the heat. These plants are listed below in the approximate order of their frequency:

1. Little Blue Pentstemon (Pentstemon linarloides)
2. Snow Berry (Symphoricarpos oreophilus)
3. Gambell's Oak (Quercus gambellii)
4. Snake Weed (Gutierrezia microcephala)
5. Quaker Bonnets (Lupinus a pathulatus)
6. Black Sage (Artemisia tridentata)
7. Trefoil (Lotus wrightii)

In addition to the suppressed plants which have become dormant due to the fire, there are a number of other conspicuous plants which have recently migrated to the site. They are listed below in the approximate order of their frequency:

1. Beggar's Ticks (Lappula redouskii occidentalis)
2. Indian Tobacco (Nicotiana attenuata)
3. Door Weed (Polygonum arviculare)
4. Lambs Quarters (Chenopodium album)
5. Alfilaria (Erodium cicutarium)
6. Russian Thistle (Salsola pestifer)
7. Red Root (Amaranthus graecizans)
8. Blue Bells (Pentstemon cyananthus)
9. Scarlet Bugler (Pentstemon bridgesii)
10. Porcupine Grass (Stipa neo-mexicana)

One interesting feature about this last named group of plants is that the seeds of most of them are adapted for dispersal by the wind or animals. It is this quality, probably more than any other single factor, which accounts for their establishment on the burn.

This area will present a changing picture of plant life for many years as new species migrate to the sites and compete with those already there. This competitive process will be a feature of this area for a long time to come - until the pinyon - juniper forest is again established on the site. The coming of these two trees will stabilize the changing plant picture because there are practically no plants capable of effective competition with them as long as the present climatic factors remain unchanged.

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