Effect of habitat and substrate quality on Douglas fir litter decomposition in western Oregon

1977 ◽  
Vol 55 (12) ◽  
pp. 1632-1640 ◽  
Author(s):  
Robert Fogel ◽  
Kermit Cromack Jr.
Keyword(s):  
Lignin Content ◽  
C:N Ratio ◽  
Growth Index ◽  
Moisture Stress ◽  
Douglas Fir ◽  
Linear Regression Models ◽  
Female Cone ◽  
Substrate Quality ◽  
Woody Litter ◽  
Plant Moisture

Linear regression models were developed for Douglas fir needle, female cone, branch, and bark decomposition in seven stands representing four mature vegetation types in western Oregon. Rate constants (k) for annual weight loss of needles ranged from 0.22 to 0.31 year−1, from 0.047 to 0.083 year−1 for cones, from 0.059 to 0.089 year−1 for branches, and from 0.005 to 0.040 year−1 for bark. The decomposition constant (k) of needles had a negative linear correlation (P < 0.01) with maximum plant moisture stress and temperature growth index of the seven stands. In comparing substrate quality of needle and woody litter components, k was more closely correlated with lignin content than with C:N ratio.

Predicting field performance of Douglas-fir seedlings: comparison of root growth potential, vigor and plant moisture stress

New Forests ◽  
1987 ◽  
Vol 1 (3) ◽  
pp. 153-169 ◽  
Author(s):  
Douglas D. McCreary ◽  
Mary L. Duryea
Keyword(s):  
Root Growth ◽  
Field Performance ◽  
Moisture Stress ◽  
Douglas Fir ◽  
Growth Potential ◽  
Root Growth Potential ◽  
Plant Moisture

HOST FOLIAGE IN THE SUSCEPTIBILITY OF FOREST SITES IN CENTRAL CALIFORNIA TO OUTBREAKS OF THE DOUGLAS-FIR TUSSOCK MOTH, ORGYIA PSEUDOTSUGATA (LEPIDOPTERA: LYMANTRIIDAE)

1981 ◽  
Vol 113 (4) ◽  
pp. 325-332 ◽  
Author(s):  
R. R. Mason
Keyword(s):  
Egg Production ◽  
Moisture Stress ◽  
Site Index ◽  
Douglas Fir ◽  
Higher Plant ◽  
Central California ◽  
Tussock Moth ◽  
Orgyia Pseudotsugata ◽  
Forest Sites ◽  
Plant Moisture

AbstractHost foliage was evaluated for nonpreference and antibiosis by field rearing Douglas-fir tussock moth larvae, Orgyia pseudotsugata (McDunnough), (instars 2–6) at typical outbreak and non-outbreak forest sites in central California. Nonpreference was evaluated by comparing frass production and antibiosis by comparing survival, pupation, and fecundity on the different sites. Typical outbreak sites had a lower site index and higher plant moisture stress than typical non-outbreak sites. Production of frass for all crown levels collectively was not significantly different between sites, although more frass was produced in the tops of trees on outbreak sites. Survival and pupation were also not significantly different between sites, but egg production was 28% higher on outbreak sites than non-outbreak sites. If differences in foliage quality did exist between sites, they did not affect the tussock moth enough to explain observed differences in population numbers.

scholarly journals Mapping of Quantitative Trait Loci Controlling Adaptive Traits in Coastal Douglas Fir. III. Quantitative Trait Loci-by-Environment Interactions

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1489-1506
Author(s):  
Kathleen D Jermstad ◽  
Daniel L Bassoni ◽  
Keith S Jech ◽  
Gary A Ritchie ◽  
Nicholas C Wheeler ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Complex Traits ◽  
Moisture Stress ◽  
Interval Mapping ◽  
Douglas Fir ◽  
Adaptive Traits ◽  
Growth Cessation ◽  
Trait Loci ◽  
Growth Initiation

Abstract Quantitative trait loci (QTL) were mapped in the woody perennial Douglas fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) for complex traits controlling the timing of growth initiation and growth cessation. QTL were estimated under controlled environmental conditions to identify QTL interactions with photoperiod, moisture stress, winter chilling, and spring temperatures. A three-generation mapping population of 460 cloned progeny was used for genetic mapping and phenotypic evaluations. An all-marker interval mapping method was used for scanning the genome for the presence of QTL and single-factor ANOVA was used for estimating QTL-by-environment interactions. A modest number of QTL were detected per trait, with individual QTL explaining up to 9.5% of the phenotypic variation. Two QTL-by-treatment interactions were found for growth initiation, whereas several QTL-by-treatment interactions were detected among growth cessation traits. This is the first report of QTL interactions with specific environmental signals in forest trees and will assist in the identification of candidate genes controlling these important adaptive traits in perennial plants.

Controls on Decomposition Processes in Alpine Tundra

2001 ◽  
Author(s):  
Timothy R. Seastedt ◽  
Marilyn D. Walker
Keyword(s):  
Low Temperatures ◽  
Lignin Content ◽  
Research Effort ◽  
Arctic Tundra ◽  
Decay Rates ◽  
Wet Meadow ◽  
Substrate Quality ◽  
Decomposition Processes ◽  
1960S And 1970S ◽  
The 1960S

The snowpack gradient in the alpine generates a temperature and moisture gradient that largely controls organic matter decomposition. While low temperatures constrain decomposition and mineralization (chapter 12), moisture appears to be the strongest source of landscape variation in the alpine, with surface decay rates of plant materials highest in moist and wet meadow habitats. Despite a longer snow-free season and higher surface temperatures in dry meadows, decay in these areas is substantially lower than in moist meadows. Studies of decay rates of roots within the soil indicate that decay is uniformly low in all habitats and is limited by low temperatures and perhaps by the absence of certain groups of decomposer invertebrates. As in other ecosystems, substrate quality indices such as nitrogen and lignin content can be shown to be important factors influencing the rate of decay of specific substrates. Alpine ecosystems were overlooked during the flurry of activity associated with the extensive ecosystem science programs of the 1960s and 1970s. With the few exceptions to be discussed here, decomposition studies in cold regions were conducted in arctic tundra or northern temperate and boreal forests. The need for this information in conjunction with efforts to understand carbon cycling in the alpine stimulated a substantial research effort in the 1990s. Studies have included both the effects of landscape location on decay (O’Lear and Seastedt 1994; Bryant et al. 1998), information on the importance of substrate chemistry on decomposition processes (Bryant et al. 1998), and preliminary information on some of the decomposer organisms (O'Lear and Seastedt 1994; Addington and Seastedt 1999). Niwot Ridge researchers also participated in the Long-term Intersite Decomposition Experiment Team (LIDET) study, which involved placement of a dozen different litter types in the alpine and in 27 other sites from the tropics to the arctic tundra (Harmon 1995). All but one of the plant species used in the LIDET experiments were exotic to the alpine. Collectively these studies have provided sufficient information to represent the alpine in global decomposition modeling efforts.

Biomass and nutrient content of Douglas-fir logs and other detrital pools in an old-growth forest, Oregon, U.S.A.

1992 ◽  
Vol 22 (10) ◽  
pp. 1536-1546 ◽  
Author(s):  
Joseph E. Means ◽  
Paul C. MacMillan ◽  
Kermit Cromack Jr.
Keyword(s):  
Forest Floor ◽  
Soluble Fraction ◽  
Close Association ◽  
C:N Ratio ◽  
Mineral Soil ◽  
Nutrient Content ◽  
Douglas Fir ◽  
Area Index ◽  
Old Growth Forest ◽  
N Release

Logs, forest floor, and mineral soil were sampled and measured, and snags were measured, in a 450-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand on the H.J. Andrews Experimental Forest, Oregon. Logs, some still identifiable after 300 years on the forest floor, contained large amounts of organic matter (222 Mg/ha), C (100 Mg/ha), water (559–10 700 L/log), N (183 kg/ha), and Ca (141 kg/ha), and smaller amounts of P (5.5 kg/ha), K (22 kg/ha), Mg (14 kg/ha), and Na (3.7 kg/ha). Logs and snags covered about 17% of the forest floor and had an all-sided area index of 0.69 m2/m2. Through mineralization, C, N, and K were lost through time; Ca and Mg increased; and P and Na increased then decreased, showing no net change. Also through mineralization, cellulose and hot acid detergent soluble fraction decreased more rapidly than lignin. Lignin was apparently not lost until the later stages of decay, when N was also lost in significant amounts. This parallels the shift from initial dominance by white rots that degraded cellulose and lignin to later dominance by brown rots that preferentially degraded cellulose. Lignin and cellulose were eventually lost at more similar rates in later decay stages. This may have been due in part to a close association between the remaining cellulose and lignin in later decay stages. Lignin was a better predictor of the onset of N release than was the C:N ratio.

Effects of Plant Moisture Stress and Rainfall on Population Dynamics of the Twospotted Spider Mite (Acari: Tetranychidae)

1990 ◽  
Vol 19 (6) ◽  
pp. 1773-1779 ◽  
Author(s):  
Thomas H. Klubertanz ◽  
Larry P. Pedigo ◽  
Richard E. Carlson
Keyword(s):  
Population Dynamics ◽  
Spider Mite ◽  
Moisture Stress ◽  
Twospotted Spider Mite ◽  
Plant Moisture ◽  
Twospotted Spider

Changes in osmotic potential of Douglas-fir (Pseudotsugamenziesii) seedlings in relation to temperature and photoperiod

1989 ◽  
Vol 19 (4) ◽  
pp. 413-421 ◽  
Author(s):  
R. van den Driessche
Keyword(s):  
Osmotic Potential ◽  
Moisture Stress ◽  
Douglas Fir ◽  
Ambient Conditions ◽  
Xylem Water Potential ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Curve Method ◽  
Volume Method ◽  
Lower Irradiance

The influences of temperature and photoperiod on osmotic potential (ψπ) at full turgor (ψπSAT) of container-grown Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings, which had completed one growing season, were examined in four experiments. Osmotic potential was measured cryoscopically on expressed sap and also by the pressure volume curve method in experiment 4. In experiment 1, started in January when ψπSAT was low, seedlings exposed to 25 °C for 5 weeks showed an increase in ψπSAT of 0.48 MPa compared with seedlings held at 8 °C, which showed little increase. There were no differences in ψπSAT between 8- and 16-h photoperiods. In experiment 2, started in September when ψπSAT was relatively high, seedlings of interior origin showed decreases in ψπSAT at 8 °C under an 8-h photoperiod (0.55 MPa) and at 25 °C under a 16-h photoperiod (0.69 MPa). Relatively little decrease in ψπSAT occurred in interior seedlings at 8 °C under a 16-h photoperiod. Coastal seedlings showed no decrease in ψπSAT in this experiment. In experiment 3, seedlings were exposed to 1 and 8 °C under an 8-h photoperiod, but at lower irradiance levels (85 μE•m−2•s−1) than those used in the other experiments (340 μE•m−2•s−1). Starting at values of about −1.9 MPa in October, ψπSAT decreased, on average, for coastal and interior seedlings by 0.76 MPa at 1 °C and 0.42 MPa at 8 °C over 6 weeks. Values for coastal seedlings decreased less (0.36 MPa) than those for interior seedlings (0.83 MPa). In experiment 4, seedlings were maintained under ambient conditions outdoors (mean temperatures of 5 °C day and 3 °C night), or at 12 or 25 °C under a 10-h photoperiod, in January and February. After 5 weeks of treatment, ψπSAT at 25 °C was 0.50 MPa, measured cryoscopically, or 0.80 MPa, measured by the pressure-volume method, higher than for seedlings under ambient conditions. At the turgor loss point (ψπSAT), ψπ was 1.36 MPa higher at 25 °C than at ambient temperature. The increase in ψπSAT at the beginning of the season and the reduction of ψπSAT at the end of the season were therefore dependent on temperature, but an interaction of photoperiod with temperature was observed in September. Index of injury values, calculated from leakage of electrolytes from drought-stressed needles and stems, showed a linear relationship to moisture stress between − 10 and − 2 MPa xylem water potential. In experiment 4, needle and stem index of injury values increased with increase in temperature, as did ψπSAT and ψπTLP values, tending to confirm that information about drought tolerance can be obtained by either method.

Patterns of log decay in old-growth Douglas-fir forests

1987 ◽  
Vol 17 (12) ◽  
pp. 1585-1595 ◽  
Author(s):  
Phillip Sollins ◽  
Steven P. Cline ◽  
Thomas Verhoeven ◽  
Donald Sachs ◽  
Gody Spycher
Keyword(s):  
C:N Ratio ◽  
Dry Weight ◽  
Douglas Fir ◽  
Time Span ◽  
Western Hemlock ◽  
Tissue Type ◽  
Old Growth ◽  
Total N ◽  
Red Cedar ◽  
Western Red Cedar

Fallen boles (logs) of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and western red cedar (Thujaplicata Donn) in old-growth stands of the Cascade Range of western Oregon and Washington were compared with regard to their physical structure, chemistry, and levels of microbial activity. Western hemlock and western red cedar logs disappeared faster than Douglas-fir logs, although decay rate constants based on density change alone were 0.010/year for Douglas-fir, 0.016/year for western hemlock, and 0.009/year for western red cedar. We were unable to locate hemlock or red cedar logs older than 100 years on the ground, but found Douglas-fir logs that had persisted up to nearly 200 years. Wood density decreased to about 0.15 g/cm3 after 60–80 years on the ground, depending on species, then remained nearly constant. Moisture content of logs increased during the first 80 years on the ground, then remained roughly constant at about 250% (dry-weight basis) in summer and at 350% in winter. After logs had lain on the ground for about 80 years, amounts of N, P, and Mg per unit volume exceeded the amount present initially. Amounts of Ca, K, and Na remained fairly constant throughout the 200-year time span that was studied (100-year time span for Na). N:P ratios converged toward 20, irrespective of tree species or wood tissue type. C:N ratios dropped to about 100 in the most decayed logs; net N was mineralized during anaerobic incubation of most samples with a C:N ratio below 250. The ratio of mineralized N to total N increased with advancing decay. Asymbiotic bacteria in fallen logs fixed about 1 kg N ha−1 year−1, a substantial amount relative to system N input from precipitation and dry deposition (2–3 kg ha−1 year−1).

scholarly journals Fungal Community, Not Substrate Quality, Drives Soil Microbial Function in Northeastern U.S. Temperate Forests

2020 ◽  
Vol 3 ◽  
Author(s):  
Amelia A. Fitch ◽  
Ashley K. Lang ◽  
Emily D. Whalen ◽  
Kevin Geyer ◽  
Caitlin Hicks Pries
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Community Composition ◽  
Fungal Community ◽  
Enzyme Production ◽  
C:N Ratio ◽  
Am Fungi ◽  
Fungal Community Composition ◽  
Substrate Quality ◽  
Soil Microbial

Mycorrhizal fungi can affect soil organic matter cycling through several mechanisms including priming, nutrient competition, and direct enzyme production. Differences in nutrient foraging strategies between ectomycorrhizal (EcM) and arbuscular mycorrhizal (AM) fungi produce divergent belowground dynamics: where EcM can take up organic nitrogen and directly break down soil organic matter (SOM) by producing enzymes, AM fungi are limited to scavenging mineral N. EcM-associated tree species also have leaf litter with relatively higher ratios of carbon to nitrogen (C:N), and belowground saprotrophic communities more dominated by fungi. Consequently, free-living microbes in EcM-dominated soils should experience nitrogen limitation, with subsequent increases in enzyme production and decreased carbon use efficiency (CUE). However, the relative importance of the effects of substrate quality and fungal community composition on enzyme production and CUE are unclear. To assess this distinction, we sampled the organic horizon and 10 cm of the mineral horizon in northern temperate forest soils along a gradient of EcM dominance. We characterized fungal community composition by measuring EcM relative abundances from extracted fungal DNA and the fungal to bacterial (F:B) ratios from phospholipid fatty acid (PLFA) analysis. We assessed soil substrate quality as the soil C:N ratio. Soil microbial functions were measured as potential activities of five hydrolytic and two oxidative enzymes, and microbial CUE. We found that the fungal community, represented by either the F:B ratio, EcM relative abundance, or both, affected CUE and six measured enzyme activities, while the C:N ratio affected only oxidative and chitin-targeting extracellular enzyme activities. Our results highlight the use of EcM relative dominance as a predictor of soil microbial community composition and function independent of substrate quality.

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