River Experimental Forest Research Articles

Biogeochemistry of Adjacent Conifer and Alder‐Conifer Stands

To determine the long—term effect of alder on soil fertility, biogeochemical fluxes were measured and calculated for two pairs of adjacent, 55—yr—old stands dominated by conifers, primarily Douglas—fir (Pseudotsuga menziesii), and by conifers and nitrogen—fixing red alder (Alnus rubra). At a low—fertility site in the Wind River Experimental Forest in southwestern Washington, biomass of the alder—conifer stand (289 Mg/ha) exceeded that of the conifer stand (171 Mg/ha), and the aboveground net primary production (ANPP) of the alder—conifer stand (10.3 Mg.ha—1.yr—1) was more than twice that of the conifer stand (4.8 Mg.ha—1.yr—1). At a more fertile site in the Cascade Head Experimental Forest in western Oregon, both biomass and ANPP were higher than at Wind River, and biomass and ANPP were higher in the conifer stand (584 Mg/ha and 19.2 Mg.ha—1.yr—1) than in the alder—conifer stand (342 Mg/ha and 10.7 Mg.ha—1.yr—1). Nitrogen accretion in the alder—conifer stand at Wind River averaged 54 kg.ha—1.yr—1 for the 52 yr since stand establishment, with a current rate of N fixation of °75 kg.ha—1.yr—1. For the alder—conifer stand at Cascade Head, N accretion averaged 73 kg.ha—1.yr—1 for 55 yr, with a current N—fixation rate of 85 kg.ha—1.yr—1. The cycling of all nutrient appeared very malleable under the influence of alder. At Wind River, return of nutrients in fine litterfall in the alder—conifer stand ranged from 1.5 (P) to 7.9 (N) times those in the conifer stand; whereas at Cascade Head, these ratios ranged from 1.7 (S) to 4.2 (N). Nutrient—use efficiencies (kilograms of ANPP per kilogram of nutrient uptake) were generally lower for the alder—conifer stands at both sites. Denitrification appeared negligible (<0.3 kg.ha—1.yr—1) in all stands. Leaching of organic plus inorganic N ranged from °5 kg.ha—1.yr—1 for the conifer stand at Wind River, to 50 Kg.ha—1.yr—1 for the alder—conifer stand at Cascade Head.

Soil Source, Seed Source, and Organic‐Matter Content Effects on Douglas‐Fir Seedling Growth

AbstractDouglas‐fir [Pseudotsuga menziesii var. glauca (Beissn.) Franco] seedling success on harvested areas in northern Idaho is often limited on harsh sites because of moisture and nutrient stress. This study was conducted to determine the importance of soil source, seed source, and organic matter on seedling growth and nutrition. Soil and seed were taken from both high‐ and low‐elevation sites at the Priest River Experimental Forest, Priest River, ID. In a greenhouse, seed was sown in both home‐source soil (taken from local seed‐collection zone) and nonsource soil (taken from opposite seed‐collection zone) mixes. Soil mixes included 100% organic, 50% organic/50% mineral, or 100% mineral soil. Seedlings were measured for height, bud length, root collar diameter, dry root and shoot weight, total N, total P, K, and number of ectomycorrhizal roots tips g−1 of dry root. Both soil and seed sources had similar nutrient and growth characteristics for each of the three soil mixes. One hundred percent organic soils, after only one growing season, produced seedlings that were significantly taller and had greater bud length, root collar diameter, and biomass than those growing in either mineral soil or the organic/mineral mix. Total N and P uptake was greater in the organic soil than in the mineral soil or the mix, but K uptake was greater in pure mineral soil. Low‐elevation seed‐source trees were always taller than their high‐elevation counterparts, an apparent result of adaptation to longer growing seasons. The best ectomy‐corrhizal colonization took place in the mineral soil mix. Ectomy‐corrhizae were most prolific on seedlings grown in nonsource soil when compared with those grown in home‐source soil. Regeneration success in the Inland Northwest will be substantially improved by maintaining the integrity of organic horizons on harvested areas and by adhering closely to seed‐transfer‐zone guidelines.

Mineralization and immobilization of soil nitrogen in two Douglas-fir stands 15 and 22 years after nitrogen fertilization

Additions of 15N-labelled ammonium chloride were used to examine the role of microbial immobilization in long-term growth response of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations to nitrogen fertilization. Soil samples were collected in the summer of 1986 from fertilized (448 or 470 kg N/ha) and nonfertilized plots at previously established N fertilization experiments near Shawnigan Lake, British Columbia, and the Wind River Experimental Forest near Carson, Washington. Douglas-fir on these sites were reported to still be responding to N fertilization after 12 and 18 years. Less than 2% of the added 15N was recovered as mineral N after a 14-day laboratory incubation of soil samples from the fertilized and nonfertilized plots. This indicates that gross mineralization could be over 50 times greater than net mineralization in these infertile soils if the remaining 98% of the added 15N was all biologically immobilized. Net mineralization was significantly greater (p ≤ 0.10) in soils from the fertilized plots than in those from the non-fertilized plots at the Wind River site. Though the current differences in N availability did not appear to be related to differences in microbial immobilization, such large rates of immobilization warrant closer scrutiny as a factor in long-term response to fertilization.

Long-term increase of nitrogen availability from fertilization of Douglas-fir

Most Douglas-fir stands respond to nitrogen fertilization by increasing stem growth for less than 8 years, but one plantation at the United States Forest Service Wind River Experimental Forest has responded for over 15 years. The nitrogen concentration of foliage and fresh litter were higher in the fertilized (applied at 470 kg N/ha) plots 18 years after fertilization. Retranslocation of N from senescent needles was not affected and stem growth per unit N in the canopy was similar between unfertilized and fertilized plots. An index of soil N availability in the fertilized plots was twice that of unfertilized plots. The higher stem growth, leaf area, and stem growth per unit leaf area appeared related to a sustained increase in soil N availability rather than increased N-use efficiency. Soil N transformation processes need to be examined to complete the explanation of the unusually prolonged fertilizer response in these plots.

Adaptation of Pinuscontorta populations to heterogeneous environments in northern Idaho

Genetic variation among 28 lodgepole pine (Pinuscontorta Dougl.) populations from northern Idaho was studied in three contrasting environments. Populations were located within 55 km of the Priest River Experimental Forest where 4-year-old seedlings were compared in environments at 750, 1200, and 1500 m elevation. Statistical analyses of six variables (4-year height, leaf length, freezing injury, multiple whorls, lammas growth, and adjusted height) detected differentiation among populations. Multiple regression models related adaptive differentiation to geographic and ecologic characteristics of the seed source. Elevation of the seed source, represented in a quadratic model, accounted for as much as 86% of the variance among populations. Results were used to estimate the limits and consequences of elevational transfers of seed.

History of Forest Service Research in the Central and Southern Rocky Mountain Regions, 1908–1975. By Raymond Price Frontiers of Forestry Research-Priest River Experimental Forest, 1911–1976. By Charles A. Wellner

<i>History of Forest Service Research in the Central and Southern Rocky Mountain Regions, 1908–1975.</i> By Raymond Price <i>Frontiers of Forestry Research-Priest River Experimental Forest, 1911–1976.</i> By Charles A. Wellner

Seasonal and Diurnal Water Relations of Selected Forest Species

Leaf diffusive conductance, leaf water potential, and leaf osmotic potential measurements were made on one tree species and three woody brush species on north and south aspects in the Priest River Experimental Forest of northern Idaho. Douglas maple (Acer glabrum) and western white pine (Pinus monticola) occurred on both aspects. Sitka alder (Alnus sinuata) and mallow ninebark (Physocarpus malvaceus) occurred only on north and south aspects, respectively. Physocarpus on the south aspect attained osmotic and leaf water potentials near ‐30 bars and daytime leaf diffusive conductances (reciprocal of resistance) near 0.3 cm/s. The Pinus on this site attained osmotic and leaf water potentials near °25 bars and leaf diffusive conductances near 0.06 cm/s. Osmotic potential and leaf water potential decreased to a minimum specific to each deciduous species as the season progressed. The Alnus and Acer species exhibited osmotic potentials near ‐16 bars with the Acer leaf water potential decreasing further to near ‐20 bars. The Pinus maintained a uniform osmotic potential between ‐20 and ‐25 bars throughout the year. Leaf diffusive conductance appeared to be controlled during the day by a combination of atmospheric demand, soil moisture availability, and plant adaptation to water stress. Stomatal control of leaf water potential was evident in Pinus on both aspects and in the brush species on the north but not on the south aspect.

A New Western Species of Chroogomphus

In the fall of 1964, Dr. Alexander H. Smith of the University of Michigan and I collected a rather large unknown agaric under a Douglas fir behind the headquarters building at the Priest River Experimental Forest in northern Idaho. It possessed a dry cuticle, amyloid pileus trama, as tested with Melzer's solution, long cystidia and subfusiform spores. It was without doubt a very unusual member of the genus Chroogomphus in the Gomphidiaceae. The robust size, dry cuticle, and caespitose habit of this fungus as well as the striking coloration of the stipe in the immature stages of development were different from any species yet encountered in the genus. Microscopically it had the thick-walled cystidia and the amyloid reactions of C. vinicolor (Peck) O. K. Miller.

Accumulation of Organic Matter and Soil Nitrogen Beneath A Plantation of Red Alder and Douglas‐Fir

AbstractSoil nitrogen accumulation beneath a plantation of red alder and Douglas‐fir was compared with that under a pure fir segment of the same 30‐year‐old stand on the Wind River Experimental Forest in southwestern Washington.Beneath the mixed plantation, there were significantly greater amounts of nitrogen in the forest floor and in the upper 24 inches of the mineral soil. Organic matter content in the upper 12 inches of mineral soil was also greater and bulk density at 0 to 3 inches was significantly less. Beneath the alder‐fir stand, the carbon‐nitrogen ratio was less, both in the forest floor and at 0 to 3 inches.There were 938 pounds more N per acre to a depth of 36 inches under the alder‐fir plantation. Consequently, an average of 36 pounds more soil N per acre per year has accumulated beneath the mixed stand than under pure fir.

The Contribution of Dew to the Summer Water Budget of Northern Idaho

Duration and amount of dew under a variety of topographic and vegetative-cover conditions were studied on the Priest River Experimental Forest in northern Idaho during the summer of 1958. Dew was measured by a continuous-recording device that registered the change in weight of an expanded polystyrene (Styrofoam) block. Dew deposits ranged from zero on cloudy, windy nights to a maximum of 0.014 inch during a clear night following a day with rain. Monthly amounts of dew ranged from 7 to 29 per cent of the monthly rainfall. Dew was deposited only on the flat of the Priest River Valley and along the Benton Creek valley bottom. Dew was not deposited under the forest canopy or on the slopes.

A Comparison of Season of Cambial Growth in Different Geographic Races of Pinus ponderosa

1. Radial growth was studied in forty-one trees including Pinus ponderosa Laws. and its var. scopulorum Engelm., during the calendar year 1948. These trees represented populations obtained from known sources over a wide area in the western United States and had been growing on the same habitat at Priest River Experimental Forest in northern Idaho since 1911-1917. 2. Median dates for completion of 5%, 50%, and 95% of total radial growth were May 23, June 21, and August 22. Although there was considerable variation in growing seasons within populations, there was but little difference among the populations. Susceptibility to frost damage does not appear to be correlated with radial growth that continues late in the season. In these fourteen populations representing nearly 14⚬ of latitude, daylength appears to exert no influence upon the growing season. Duration of cambial activity is not related to grouping of the populations into races on the basis of morphology and anatomy.

Soil‐freezing and forest‐cover

An important though little‐investigated problem is the relationship of soil‐freezing to forest‐cover. With the idea of determining some of the phases of soil‐freezing under different cover‐conditions, measurements of depth of frost in the ground were undertaken at the Gale River Experimental Forest in northern New Hampshire. In agreement with the exploratory character of this study, no attempt was made to analyze statistically the correlation between the depth of frost in the ground and the individual factors affecting soil‐freezing. Any definite trends, however, were noted and additional measurements taken in order to throw some light on the influence of some of the important factors.The study was initiated in the fall of 1937. On three 0.1‐acre plots established in the spruce flat and spruce swamp types and in an open field, measurements of frost‐depth were continued for three successive winters. In 1939 two additional plots, one in a fir flat, the other in a northern hardwoods type, were established and measurements continued through the winter of 1939–40. In addition to measurements on these plots, numerous borings were made in surrounding areas differing from the sample areas in drainage and soil‐texture. Most of the measurements were taken with a frozen‐soil boring tool developed especially for this purpose by B. C. Goodell.

Sterile Conks of Polyporus Glomeratus and Associated Cankers on Beech and Red Maple

In 1930 Hirt 1 reported sterile conks on beech (Fagus grandifolia Ehrhart.), which were associated with a normal fruiting body of Fomes Everhartii (Ellis & Gall.) Schrenk. During the summer of 1938 another type of sterile conk, with or without associated cankers, was found commonly on beech in the Green Mountain National Forest. These sterile conks, except for their smaller size, resembled those on birch recently reported by Campbell and Davidson 2 to be a sterile form of a Poria (probably Poria obliqua). Because of this resemblance and because P. obliqua or a similar Poria had been collected on beech in Pennsylvania and New Hampshire, it was originally thought that the sterile conks might be the sterile form of it. However, pure cultures of Polyporus glomeratus Peck, described by the writers,3 were isolated from the sterile conks and the associated decay. In addition, P. glomeratus fruited on down beech on which there were sterile conks and cankers. Later in the season a number of red maples (Acer rubrum Linn.) on the Gale River Experimental Forest, New Hampshire, were found to be badly cankered and decayed. Sterile fungus material characteristic of P. glomeratus was associated with the cankers and pure cultures from this material and from the decay confirmed the