Treesearch

We compared growth and cone production of Douglas-fir treated 4 years earlier with ISO pounds N per acre applied as urea prill by hand and as a 32-percent N solution applied by helicopter. Nitrogen fertilization increased growth by 3 88 ft per acre during the 4 years after treatment; this 3S-percent gain was similar for both soil (prill) and foliar (solution) applications. Although cone production on the prill-treated plots averaged twofold to fourfold greater than on the control plots, these differences were not statistically significant.

Using nitrogen-fixing plants in forestry becomes financially more attractive as the costs of fertilizers and their application continue to increase. Eight legume cultivars were screened for suitability in Douglas-fir forests of southwest Oregon. The legumes were sown on concurrently fertilized and unfertilized plots within deer exclosures in three logged and burned clearcuts. Percent cover after the first and during the ninth growing season was clearly greater on 2-by 2-meter plots sown with alfalfa, crownvetch, and birds foot deervetch (trefoil) than with wetland deervetch, perennial...

Basal area response to 150 pounds of nitrogen per acre applied as urea or ammonium nitrate was monitored on 1/5-acre plots for 4 years in a recently thinned, 110-year-old, site II, Douglas-fir stand. Nitrogen fertilization significantly increased growth. Basal area increment was increased 59 percent over the controls by ammonium nitrate and 37 percent by urea. The difference in response between urea and ammonium nitrate was statistically significant. Crown class had a highly significant influence on basal area growth of individual trees; however, the increases in growth due to fertilization...

Volume growth response to 200 Ib of nitrogen per acre applied as urea or ammonium nitrate was monitored for 4 yr in an 80-yr-old, site I, Douglas-fir stand. Fertilization increased gross total cubic growth by 20 percent over the controls. Response to urea and to ammonium nitrate was similar. The rapid volume growth on the control plots, 34 2 ft 3 per acre per year, plus the substantial increase in growth on the fertilized plots, indicate the desirability of delaying final harvest of this stand.

Public and private agencies are cooperating in a study of eight thinning regimes in young Douglas-fir stands. Regimes differ in the amount of basal area allowed to accrue in growing stock at each successive thinning. All regimes start with a cornmon level-of-growing-stock which is established by a conditioning thinning. Thinning interval is controlled by height growth of crop trees, and a single type of thinning is prescribed. Nine study areas, each involving three completely random replications of each thinning regime and an unthinned control, have been established in western Oregon and...

Height growth and site index curves and equations for managed, even-aged stands of Douglas-fir (Pseudotsuga menziezii (Mirb.) Franco) east of the Cascade Range in Oregon and Washington are presented. Data were collected in stands where height growth apparently has not been suppressed by high density or top damage.

Height growth and site index curves and equations for white or grand fir growing in managed, even-aged pure stands or mixed with other conifers east of the Cascade Range in Oregon and Washington are presented. Data were collected in stands where height growth apparently has not been suppressed by high density or top damage.

Area and volume data are given for the first intensive inventory of a 188,000-acre unit on the west side of Cook Inlet, 130 miles southwest of Anchorage. Commercial forest land totaled 45 thousand acres with a total cubic volume of 105 million feet. The major species component is a hybrid mixture of Sitka and white spruce. An introductory section has comments on this hybridization, forest location, use, defect, regeneration, and stocking.

A survey of shelterwood cuttings in mixed conifer forests in the eastern Oregon Cascade Range showed that, on the average, shelterwood units were well stocked with a mixture of advance, natural subsequent, and planted reproduction of a number of species. Because of slow invasion by understory vegetation, frequent heavy seed crops, and adequate density of the overstory, natural regeneration was prolific on most units. Planting is recommended only as a supplemental reforestation method. Greater stocking was associated with increasing overstory density and more exposed mineral soil; such...

After a near record output in 1976, Washington log production declined 5.4 percent in 1977 to 6.59 billion board feet. Western Washington production was 415 million board feet lower than in 1976; eastern Washington, 36 million board feet higher. The private harvest was 62 percent of the total, the lowest in 4 years. For the past 15 years, the harvest from the western half of the State has remained a steady 83 to 84 percent of the State total.