Aspen Bibliography

Title

Influence of High Light Intensity on Survival of Planted Englemann Spruce

Authors

Frank Ronco

Document Type

Article

Journal/Book Title/Conference

Forest Science

Volume

16

First Page

331

Last Page

339

Publication Date

1970

Abstract

Results of three studies on photosynthesis and needle water deficits are presented. Photosynthesis was higher for Engelmann spruce seedlings grown in the shade than in the open, but it was not significantly different for lodgepole pine seedlings. Spruces reached near-maximum photosynthesis at 4,000 to 5,000 ft-c, but pines did not appear light-saturated even at 12,000 ft-c. Photosynthesis and respiration of potted spruce seedlings were highest at moisture deficits less than 10 percent; with deficits above 20 percent, photosynthesis was zero and respiration minimal. At a deficit of 58 percent seedlings died. Moisture deficits of seedlings during the summer after field planting were below 31 percent and did not differ significantly between sunrise or mid-afternoon measurements, nor between shaded or open-grown treatments. These and other results suggest that solarization occurs in unshaded spruce, has a deleterious effect on photosynthesis, and may be associated with the high mortality in plantations at elevations above 10,000 ft. Forest Sci. 16: 331-339.