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1
Erickson, Heather E., R. L. Edmonds, and C. E. Peterson. "Decomposition of logging residues in Douglas-fir, western hemlock, Pacific silver fir, and ponderosa pine ecosystems." Canadian Journal of Forest Research 15, no. 5 (1985): 914–21. http://dx.doi.org/10.1139/x85-147.
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Logging residue decomposition rates were determined in four conifer forest ecosystems in the State of Washington, U.S.A. (coastal western hemlock, Puget lowland Douglas-fir, high-elevation Pacific silver fir, and eastern Cascade ponderosa pine), by examining wood density changes in a series of south-facing harvest areas with residues of different ages. Decomposition rates were determined for two diameter classes (1–2 and 8–12 cm) and two vertical locations (on and >20 cm above the soil surface). Pacific silver fir and ponderosa pine ecosystems had the lowest k values (0.005 and 0.010 year−1, respectively) followed by Douglas-fir (range, 0.004–0.037 year−1) and western hemlock (range, 0.010–0.030 year−1). Small-diameter residues decomposed at rates significantly slower than large-diameter residues in Douglas-fir and western hemlock ecosystems; this relationship was also implied in the other ecosystems. In all four ecosystems, dry season moisture contents were lower in smaller-diameter residues. Moisture levels associated with small-diameter residues were too low for significant decomposition to occur during the dry summer period and probably contributed to the slow annual decay rates. Residues located above the soil surface decomposed significantly slower than residues on the soil surface only in the Douglas-fir ecosystem. Dry season residue moisture, rather than initial lignin concentration, appeared to be the dominant factor determining residue decomposition rates on exposed harvested areas.
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Jurgensen, M. F., M. J. Larsen, R. T. Graham, and A. E. Harvey. "Nitrogen fixation in woody residue of northern Rocky Mountain conifer forests." Canadian Journal of Forest Research 17, no. 10 (1987): 1283–88. http://dx.doi.org/10.1139/x87-198.
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N fixation rates, as estimated by the acetylene reduction technique, were determined for large woody residues on four old growth conifer sites in western Montana and northern Idaho. Residue loadings ranged from <50 Mg ha−1 on a warm, dry Douglas-fir site in Montana to >150 Mg ha−1 on a highly productive, wet, cedar–hemlock site in northern Idaho. Lignin and carbohydrate analyses indicated that wood on these sites was being decayed primarily by brown rot fungi. Ethylene production rates increased on all sites as wood decay progressed. Assuming that N-fixing bacteria were active for 180 days year−1, N fixed in woody residues ranged from a high of nearly 1.5 kg ha−1 year−1 on a cedar–hemlock site to a low of 0.16 kg ha−1 year−1 on a Douglas-fir site. The application of the N fixation results from this study to the northern Rocky Mountain region indicated that the majority of stands in the Douglas-fir, subalpine fir, and cedar–hemlock cover types would have N gains <0.5 kg ha−1 year−1. However, in some areas where residue loadings are heavy, such as overmature stands on cool, moist sites, or following harvesting, N gains could be much greater.
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Dien, Bruce S., J. Y. Zhu, Patricia J. Slininger, et al. "Conversion of SPORL pretreated Douglas fir forest residues into microbial lipids with oleaginous yeasts." RSC Advances 6, no. 25 (2016): 20695–705. http://dx.doi.org/10.1039/c5ra24430g.
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Edmonds, Robert L., Daniel J. Vogt, David H. Sandberg, and Charles H. Driver. "Decomposition of Douglas-fir and red alder wood in clear-cuttings." Canadian Journal of Forest Research 16, no. 4 (1986): 822–31. http://dx.doi.org/10.1139/x86-145.
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Decomposition rates of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and red alder (Alnusrubra Bong.) wood (simulating logging residues) were determined in clear-cuttings at the Charles Lathrop Pack Experimental Forest of the University of Washington, which is located approximately 120 km south of Seattle, WA. The influence of diameter (1–2, 4–6, and 8–12 cm), vertical location (buried, on the soil surface, and elevated), season of logging (summer and winter), aspect (north and south), and wood temperature, moisture, and chemistry on wood decomposition rates were determined. Red alder wood decomposed faster (k = 0.035–0.517 year−1) than Douglas-fir wood (k = 0.006–0.205 year−1). In general, buried wood decomposed faster than surface wood, which decomposed faster than elevated wood. Small diameter wood generally decomposed faster than larger diameter wood. Aspect and season of logging had little influence on decomposition rates. Moisture and temperature were the dominant factors related to Douglas-fir wood decomposition, with initial chemistry playing a minor role. Initial wood chemistry, particularly soda solubility, was the dominant factor related to red alder wood decomposition.
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Socha, Aaron M., Samuel P. Plummer, Vitalie Stavila, Blake A. Simmons, and Seema Singh. "Comparison of sugar content for ionic liquid pretreated Douglas-fir woodchips and forestry residues." Biotechnology for Biofuels 6, no. 1 (2013): 61. http://dx.doi.org/10.1186/1754-6834-6-61.
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Biswas, Rajib, Philip J. Teller, and Birgitte K. Ahring. "Pretreatment of forest residues of Douglas fir by wet explosion for enhanced enzymatic saccharification." Bioresource Technology 192 (September 2015): 46–53. http://dx.doi.org/10.1016/j.biortech.2015.05.043.
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Zhang, Chao, J. Y. Zhu, Roland Gleisner, and John Sessions. "Fractionation of Forest Residues of Douglas-fir for Fermentable Sugar Production by SPORL Pretreatment." BioEnergy Research 5, no. 4 (2012): 978–88. http://dx.doi.org/10.1007/s12155-012-9213-3.
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Srinivas, Keerthi, Fernanda de Carvalho Oliveira, Philip Johan Teller, Adilson Roberto Gonҫalves, Gregory L. Helms, and Birgitte Kaer Ahring. "Oxidative degradation of biorefinery lignin obtained after pretreatment of forest residues of Douglas Fir." Bioresource Technology 221 (December 2016): 394–404. http://dx.doi.org/10.1016/j.biortech.2016.09.040.
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Alvarez-Vasco, Carlos, Mond Guo, and Xiao Zhang. "Dilute Acid Pretreatment of Douglas Fir Forest Residues: Pretreatment Yield, Hemicellulose Degradation, and Enzymatic Hydrolysability." BioEnergy Research 8, no. 1 (2014): 42–52. http://dx.doi.org/10.1007/s12155-014-9496-7.
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Bloomberg, W. J., and G. Reynolds. "Equipment Trials for Uprooting Root-Rot-Infected Stumps." Western Journal of Applied Forestry 3, no. 3 (1988): 80–82. http://dx.doi.org/10.1093/wjaf/3.3.80.
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Abstract Root residues were measured following stump-root extraction 1 year after harvesting a 55-year-old Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stand with 20% infestation of Phellinus weirii (Murr. Gilbertson) root rot. A D8 Cat, a 180-hp (large) backhoe, and a 115-hp (small) backhoe were each used to uproot stumps on 1.2-1.3 ha blocks. All treatments resulted in less than 10% of root volume remaining in the soil compared with pretreatment volumes calculated from dbh-root volume relationships on a similar site. Average numbers and lengths of root residues/m³ soil were significantly greater for the small backhoe than for the other treatments, and volume was greatest for the D8 Cat treatment. The large backhoe treatment resulted in smaller residual volumes than the other treatments. West. J. Appl. For. 3(3):80-82, July 1988.
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Rofii, Muhammad Navis, Satomi Yumigeta, Shigehiko Suzuki, and Tibertius Agus Prayitno. "Effects of Shelling Ratio and Particle Characteristic on Physical Properties of Three-Layered Particleboard Made from Different Wood Species." Wood Research Journal 4, no. 1 (2017): 25–30. http://dx.doi.org/10.51850/wrj.2013.4.1.25-30.
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Wood waste materials such as flakes, particles, sawdust, planer shaving, which are residues from furniture industry can be utilized to manufacture many composites such as particleboard. The most commonly used particleboard has three layers: two face layers and one core layer. The face layers consist of fine particles and the core layer is made of coarse particles.This study aimed to show the effect of shelling ratio and particle characteristic on physical properties of three-layer particleboard with high density core and different particles on surface layers. The materials used in this study were hinoki (Chamaecyparis obtusa) strand and knife-milled Douglas-fir (Pseudotsuga manziesii) as surface layers and hammer-milled matoa (Pometia sp.) as core layer. The wood particles were collected from a wood company. Adhesive used was MDI resin (methylene diphenyl diisocyanate) with 6 % content in mat preparation. The pressing conditions were: temperature 180°C, pressure 3 MPa and pressing time 5 min. The target density was 0.72 g/cm3 with board size of 340 mm x 320 mm x 10 mm. Factors used in this study were layer structure according to board shelling ratio and particle characteristic. The parameters of this study were density, moisture content, thickness swelling, water absorption, linear expansion and vertical density profile.The results of this study indicate that all boards meet the requirements of JIS A 5908-2003. Higher shelling ratio of surface layers resulted in higher physical performance of three-layer particleboard. In terms of particle type, hinoki strands showed the best performance in board density and linear expansion, while Douglas-fir particle showed the best performance in moisture content, thickness swelling and water absorption. Improvement of physical properties of particleboard with high density wood particles in core layer can be conducted by adding surface layer with higher quality wood particles such as hinoki strands or Douglas-fir particles. Compared to Douglas-fir particles, hinoki strands as surface layers contribute to higher enhancement of three-layer particleboard with matoa as the core layer.
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Kitanovic, Smiljka, Chad A. Marks-Fife, Quincy A. Parkes, P. Ross Wilderman, James R. Halpert, and M. Denise Dearing. "Cytochrome P450 2B diversity in a dietary specialist—the red tree vole (Arborimus longicaudus)." Journal of Mammalogy 99, no. 3 (2018): 578–85. http://dx.doi.org/10.1093/jmammal/gyy039.
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Abstract Although herbivores rely on liver enzymes to biotransform plant secondary metabolites ingested in plant-based diets, only a few enzymes from a handful of species have been characterized at the genomic level. In this study, we examined cytochrome P450 2B (CYP2B) sequence diversity and gene copy number in a conifer specialist, the red tree vole (Arborimus longicaudus). We fed captive individuals exclusively Douglas-fir (Pseudotsuga menziesii) foliage, cloned and sequenced their liver CYP2B cDNA, and estimated CYP2B gene copy number. We identified 21 unique CYP2B nucleotide sequences, and 20 unique CYP2B amino acid sequences. Gene copy number of CYP2B was estimated at 7.7 copies per haploid genome. We compared red tree vole CYP2B with CYP2B sequences of a generalist, the prairie vole (Microtus ochrogaster), found in GenBank. Our study revealed that the CYP2B enzymes of red tree voles possess unique sequences compared to CYP2B enzymes of other herbivorous species. The unique combination of amino acid residues at key substrate recognition sites of CYP2B enzymes may underlie the ability of the red tree vole to specialize on a highly toxic diet of Douglas-fir.
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He, Xiao, Lianjun Wang, and Anthony Lau. "Comparison of Gaseous Emissions from Stored Biomass Residues." E3S Web of Conferences 194 (2020): 02005. http://dx.doi.org/10.1051/e3sconf/202019402005.
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Woody biomass used as alternative fuel to generate power becomes a significant element of sustainability nowadays. Biomass is usually stored for some period before direct combustion or processing in biorefineries. The objective of this study is to quantify and compare the gas emissions from Western Red Cedar (WRC) and Douglas fir (DF) chips during storage at a range of temperatures (5-50oC) under both non-aerobic and aerobic conditions. Results showed that the dominant mechanism is different depending on the stored materials. Emissions of CO and CH4 were 2-5 orders of magnitude less than CO2 emission for both WRC and DF chips. The major components of VOCs detected by GC/MS from both materials are similar, consisting of hydrocarbons, aldehyde, terpenes, methanol, acetone, ketone, acid and esters, benzene and its derivatives. The total concentrations of VOC (TVOC) under both conditions differed with temperature, and they were much higher from the DF chips than WRC. The emission factors under the aerobic condition were higher when compared to those under the non-aerobic condition over the storage time period.
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Størdal, Ståle, and Darius M. Adams. "Testing for variation in the western Oregon softwood log price structure." Canadian Journal of Forest Research 35, no. 3 (2005): 713–23. http://dx.doi.org/10.1139/x05-008.
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Timber owners in western Oregon have been concerned about the erosion of price premiums for higher quality grades of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) sawlogs over the past decade. Time series tests indicate that the ratio of 3Saw (lower quality) to 2Saw (higher quality) sawlog prices did rise over the 19902000 period, suggesting convergence between the prices. To identify causes of this trend, we estimate reduced form equations for Douglas-fir sawlog prices with time-varying coefficients using flexible least squares. Log grade prices were related to prices of lumber by grade, prices of chipped residues, labor wage rates, and volumes of public timber supplied. Changes in the relation of log grade prices are reflected through changes in both reduced form coefficients and levels of the exogenous variables. Changes in the coefficients, in turn, may derive from shifts in the distribution of log qualities within grade categories and from grade-specific changes in sawing and log production technologies. Coefficient trends showed that higher quality lumber grades became more important for 3Saw logs during the sample period, while lower quality lumber grades and chips became more important for 2Saw, moving the log grade prices closer together. Comparison of simulated 2Saw and 3Saw prices with and without historical time patterns in the exogenous variables had little impact on their relationship, suggesting that factors shifting the coefficients may have been the primary drivers of price convergence.
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Preston, C. M., J. A. Trofymow, and J. R. Nault. "Decomposition and change in N and organic composition of small-diameter Douglas-fir woody debris over 23 years." Canadian Journal of Forest Research 42, no. 6 (2012): 1153–67. http://dx.doi.org/10.1139/x2012-076.
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Managing second-growth forests for multiple benefits requires enhanced information on decomposition of woody debris generated during forestry operations. Experimental thinning and biomass sampling at the Shawnigan Lake Research Forest on southern Vancouver Island facilitated retrospective sampling of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) stem sections (4.9–21.5 cm diameter) from 0 to 23 years after cutting. A sigmoidal pattern of density loss was observed, while a single-exponential fit gave a decay rate (k) of 0.058 year–1. Initial N concentrations were higher in bark than in sapwood and heartwood, and all increased during decay, while C/N ratios declined to around 175 for wood and 70 for bark. Nitrogen contents initially increased but tended to decline after about 50% C loss. Solid-state 13C nuclear magnetic resonance spectroscopy showed little change in organic composition, consistent with white-rot fungal decay, with only a few 19-year samples showing large increases in lignin typical of extensive brown-rot decay. Hydrolyzable monosaccharides of wood and bark were dominated by glucose followed by mannose, xylose, galactose, and arabinose. For wood, the mole fraction of mannose decreased with decomposition, whereas those of glucose, arabinose, and galactose increased slightly and that of xylose remained constant for both brown and white rot. Our results support indications that decomposition of smaller diameter woody debris from managed conifer forests will likely be dominated by white-rot fungi, leaving residues high in cellulose rather than in lignin.
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Ben, Haoxi, Fengze Wu, Zhihong Wu, Guangting Han, Wei Jiang, and Arthur J. Ragauskas. "A Comprehensive Characterization of Pyrolysis Oil from Softwood Barks." Polymers 11, no. 9 (2019): 1387. http://dx.doi.org/10.3390/polym11091387.
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Pyrolysis of raw pine bark, pine, and Douglas-Fir bark was examined. The pyrolysis oil yields of raw pine bark, pine, and Douglas-Fir bark at 500 °C were 29.18%, 26.67%, and 26.65%, respectively. Both energy densification ratios (1.32–1.56) and energy yields (48.40–54.31%) of char are higher than pyrolysis oils (energy densification ratios: 1.13–1.19, energy yields: 30.16–34.42%). The pyrolysis oils have higher heating values (~25 MJ/kg) than bio-oils (~20 MJ/kg) from wood and agricultural residues, and the higher heating values of char (~31 MJ/kg) are comparable to that of many commercial coals. The elemental analysis indicated that the lower O/C value and higher H/C value represent a more valuable source of energy for pyrolysis oils than biomass. The nuclear magnetic resonance results demonstrated that the most abundant hydroxyl groups of pyrolysis oil are aliphatic OH groups, catechol, guaiacol, and p-hydroxy-phenyl OH groups. The aliphatic OH groups are mainly derived from the cleavage of cellulose glycosidic bonds, while the catechol, guaiacol, and p-hydroxy-phenyl OH groups are mostly attributed to the cleavage of the lignin β–O-4 bond. Significant amount of aromatic carbon (~40%) in pyrolysis oils is obtained from tannin and lignin components and the aromatic C–O bonds may be formed by a radical reaction between the aromatic and aliphatic hydroxyl groups. In this study, a comprehensive analytical method was developed to fully understand and evaluate the pyrolysis products produced from softwood barks, which could offer valuable information on the pyrolysis mechanism of biomass and promote better utilization of pyrolysis products.
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Trofymow, J. A., N. C. Coops, and D. Hayhurst. "Comparison of remote sensing and ground-based methods for determining residue burn pile wood volumes and biomass." Canadian Journal of Forest Research 44, no. 3 (2014): 182–94. http://dx.doi.org/10.1139/cjfr-2013-0281.
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Following forest harvest, residues left on site are often piled and burned. Quantification of residue piles is required in many jurisdictions to estimate billable waste, harvest efficiency, smoke emissions, C budgets, and available bioenergy biomass. Piled residues and harvested wood were measured on four blocks of a second-growth Douglas-fir forest in coastal British Columbia. Pile wood volumes were determined by two ground-based methods (a Waste and Residue Survey (WRS) and a geometric equation (EEP) used for smoke emissions) and by two geospatial methods using orthophotography (GIS) and LiDAR. Eight sample piles were disassembled to determine plot densities (PD) and packing ratios (PR). Plot density did not differ between the WRS and GIS method. Packing ratios of the EEP were 50% of that of the LiDAR method. LiDAR pile bulk volume and PR were negatively correlated. Choice of LiDAR digital elevation model had no significant effect on pile bulk volumes. The WRS method underestimated pile areas by 50% and the EEP method overestimated pile bulk volumes by two times. Pile wood volumes from the WRS method (20.0 m3·ha−1 (SE 2.8)) were 30%–50% of those for all other methods (46.1–60.4 m3·ha−1). The EEP method overestimated wood volume if nonspecific PRs were used. The residues to harvest ratio for the WRS method (3.3% (SE 0.45)) was lower than for all other methods (7.5%–9.6%). Total pile wood biomass from LiDAR was 25.4 t dry mass·ha−1 (SE 5.9). Ground-based methods are still required to determine PD or PR. Since their estimation depends on the method used to determine pile area or bulk volume, and may vary with pile size and type, they remain the major source of uncertainty in determining pile wood volumes. However, use of remote sensing techniques to determine the area or bulk volume of all piles in a cutblock can improve estimates of pile wood volumes and biomass.
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Brandeis, Thomas J., Michael Newton, and Elizabeth C. Cole. "Underplanted conifer seedling survival and growth in thinned Douglas-fir stands." Canadian Journal of Forest Research 31, no. 2 (2001): 302–12. http://dx.doi.org/10.1139/x00-174.
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In a multilevel study to determine limits to underplanted conifer seedling growth, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex D. Don), and western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were planted beneath second-growth Douglas-fir stands that had been thinned to basal areas ranging from 16 to 31 m2/ha. Understory vegetation was treated with a broadcast herbicide application prior to thinning, a directed release herbicide application 2 years later, or no treatment beyond harvest disturbance. Residual overstory density was negatively correlated with percent survival for all four species. Broadcast herbicide application improved survival of grand fir and western hemlock. Western redcedar, grand fir, and western hemlock stem volumes were inversely related to overstory tree density, and this effect increased over time. There was a strong indication that this was also the case for Douglas-fir. Reduction of competing understory vegetation resulted in larger fourth-year stem volumes in grand fir and western hemlock.
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Cline, E., B. Vinyard, and R. Edmonds. "Spatial effects of retention trees on mycorrhizas and biomass of Douglas-fir seedlings." Canadian Journal of Forest Research 37, no. 2 (2007): 430–38. http://dx.doi.org/10.1139/x06-229.
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Retention forestry places seedlings in proximity to residual trees, exposing seedlings to additional sources of ectomycorrhizal fungus (EMF) inoculum. To investigate this, Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) seedlings were planted near (2–6 m) and far (16–30 m) from 44- to 72-year-old residual Douglas-fir trees in western Washington, USA. From 1998 through 2000, seedling shoot and root biomass was assessed and EMF taxa were identified using morphology and sequence analysis of internal transcribed spacer and large subunit ribosomal RNA genes. Seedlings near residual trees had significantly greater ectomycorrhiza (ECM) abundance (percent active ECM root tips), less necrotic root tips, and higher root to shoot biomass ratios. Seedlings near trees had a richness index of 4.1 EMF taxa per seedling and 42 total taxa compared with 3.5 taxa per seedling and 33 total taxa for seedlings far from trees. Proximity to residual trees may increase seedling ECM abundance and diversity.
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Schauwecker, Christoph, Milo Clauson, Matthew J. Konkler, Arijit Sinha, and Jeffrey J. Morrell. "Properties of Aging Pentachlorophenol-Treated Douglas-Fir Crossarms." Forest Products Journal 70, no. 3 (2020): 364–69. http://dx.doi.org/10.13073/fpj-d-20-00025.
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Abstract Wooden crossarms play a major role in supporting electric distribution lines in North America, but relatively few data exist on their condition as they age. The residual capacity of Douglas-fir crossarms in service in western Oregon for 45 to 60 years was investigated. Arms were sampled for residual preservative retention, the presence of visible decay fungi, and residual flexural properties; these results were then compared with three nondestructive tools. A majority of the arms tested had preservative levels well below those required for new arms, but only one decay fungus was isolated, and only five arms removed and dissected had any evidence of visible internal decay. Moduli of rupture for the arms were generally below the minimum levels required by national standards, but most still retained at least 67 percent of this value. Nondestructive evaluation tools were generally poorly correlated with flexural properties, possibly because of the heavily weathered and checked exterior condition.
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Turnblom, Eric C., and Randol L. Collier. "Growth of Residual Branches on Pruned Coastal Douglas-Fir." Western Journal of Applied Forestry 18, no. 3 (2003): 185–88. http://dx.doi.org/10.1093/wjaf/18.3.185.
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Abstract Anecdotal evidence gathered from pruning crew observations indicates that there may be enhanced branch growth at the new crown base in young pruned coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) trees compared to unpruned trees. This has the potential to reduce the quality and value of the stem above the pruned portion of the bole. An analysis of the size of branches in the remaining crown on pruned trees and matched unpruned trees of the same size at the time of pruning indicates that residual branches do not increase in diameter or length in response to light and moderate pruning. However, with a severe pruning there was a modest increase in branch length. Residual branch size in response to pruning 4 yr after treatment appears to offer no real risk in degrading quality of the unpruned portion of the stem as a cost for increasing the quality of the pruned stem. West. J. Appl. For. 18(3):185–188.
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Oleson, Karl R., and Daniel T. Schwartz. "Extractives in Douglas-fir forestry residue and considerations for biofuel production." Phytochemistry Reviews 15, no. 5 (2015): 985–1008. http://dx.doi.org/10.1007/s11101-015-9444-y.
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Kershaw Jr., John A., and Douglas A. Maguire. "Crown structure in western hemlock, Douglas-fir, and grand fir in western Washington: trends in branch-level mass and leaf area." Canadian Journal of Forest Research 25, no. 12 (1995): 1897–912. http://dx.doi.org/10.1139/x95-206.
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Extensions of a basic allometric equation applied in predicting total foliage of individual trees were developed to estimate foliage and woody components of individual branches in western hemlock (Tsugaheterophylla (Raf.) Sarg.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and grand fir (Abiesgrandis (Dougl. ex D. Don) Lindl.). Nine initial equations were fitted on both nonlinear and log-transformed scales to data collected in the western Cascade Mountains of Washington. In all cases, the logarithmic form of each equation provided the best fit to the data based on a modified likelihood criterion and residual patterns. Branch diameter was the overall best predictor of branch foliage and woody mass; however, significant (p = 0.05) improvements in fit were obtained when other structural and positional variables were included in the equations (e.g., foliated branch length and depth into crown). The effects of fertilization and site (locality) differences were explored using indicator variables for western hemlock branches. Significant site effects were observed for intercept terms for all three branch components (total foliage area, total foliage mass, and total woody mass), while fertilization effects were observed in interaction with relative height above crown base for both foliage components.
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Tinnin, Robert O. "Effect of Dwarf Mistletoe on Bole Taper and Volume in Young Douglas-Fir." Western Journal of Applied Forestry 16, no. 1 (2001): 5–8. http://dx.doi.org/10.1093/wjaf/16.1.5.
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Abstract Boles of 210 residual understory Douglas-fir trees, ranging from uninfected to heavily infected with Douglas-fir dwarf mistletoe, were measured for cylindrical form factor, Girard form class, height-to-diameter ratio, bole profile, and volume. Height-to-diameter ratio and Girard form class were significantly reduced by dwarf mistletoe across the range of infection classes. However, no effect due to infection by dwarf mistletoe was found on cylindrical form factor, and only a slight difference in bole profile between uninfected and heavily infected trees was found. These results suggest that dwarf mistletoe increases bole taper and affects the volume of younger Douglas-fir by affecting tree diameter and height but not by a substantive change in bole profile. West. J. Appl. For.16(1):5–8.
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Lam, Tzeng Yih, and Douglas A. Maguire. "Thirteen-Year Height and Diameter Growth of Douglas-Fir Seedlings under Alternative Regeneration Cuts in Pacific Northwest." Western Journal of Applied Forestry 26, no. 2 (2011): 57–63. http://dx.doi.org/10.1093/wjaf/26.2.57.
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Abstract Interest in managing Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) forests in the Pacific Northwest under silvicultural systems other than traditional clearcutting has prompted research on the efficacy of alternative systems for successful regeneration and sustained timber productivity of Douglas-fir. The College of Forestry Integrated Research Project, implemented by Oregon State University, was established to compare various ecosystem responses and public perceptions among treatments implemented under clearcutting, shelterwood-with-reserves, and group selection silvicultural systems. The objective of this analysis was to quantify the following three responses of planted Douglas-fir seedlings to initial regeneration cuts: cumulative 13-year height growth (H13yr; 1992–2004), cumulative 13-year diameter growth (D13yr; 1992–2004), and most recent 5-year height growth (ΔH5yr; 2000–2004). Differences in variability of overstory density at the treatment level led to significant differences in the variance of understory growth responses. After accounting for heterogeneous variance, analysis of variance indicated significant treatment effects for all three responses. Treatment effects were explained by the decline in H13yr, D13yr, and ΔH5yr with increasing overstory competition as represented by basal area of residual trees immediately after harvesting (initial basal area). Predicted height:diameter ratio of Douglas-fir seedlings increased as IBA increased. Under regeneration methods that retain a portion of the overstory, a residual overstory with basal area <80 ft2/ac allows establishment, growth, and continued survival of Douglas-fir regeneration during the 13 years following harvest.
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Leu, Shao-Yuan, J. Y. Zhu, Roland Gleisner, John Sessions, and Gevan Marrs. "Robust enzymatic saccharification of a Douglas-fir forest harvest residue by SPORL." Biomass and Bioenergy 59 (December 2013): 393–401. http://dx.doi.org/10.1016/j.biombioe.2013.08.014.
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Littke, K. M., T. B. Harrington, S. M. Holub, W. R. Littke, R. B. Harrison, and E. C. Turnblom. "Douglas-Fir Biomass Allocation and Net Nutrient Pools 15–20 Years after Organic Matter Removal and Vegetation Control." Forests 11, no. 9 (2020): 1022. http://dx.doi.org/10.3390/f11091022.
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Douglas-fir (Pseudotsuga menziesiivar. menziesii (Mirbel) Franco) plantation forests of the coastal Pacific Northwest have been intensively managed to improve the yield of forest products. However, the long-term effects of these management techniques have received limited research attention in this region. Three affiliate Long-Term Soil Productivity study sites were installed in Douglas-fir forests to understand the impacts of organic matter removals and vegetation control on soil productivity over time. Matlock and Fall River are located in Washington, USA and Molalla is located in Oregon. Organic matter removal treatments included traditional bole-only harvest (BO), whole tree removals (WT), and a whole tree plus coarse woody debris removal (WT+) (Fall River only). Five years of annual vegetation control (AVC) was compared with a conventional initial vegetation control (IVC) treatment at all sites. Douglas-fir biomass allocation to foliage, branch, and stem components was modeled using 15- to 20-year-old trees from this study along with 5- to 47-year-old trees from previous studies on these sites. Across all sites, model predictions indicated that the WT treatment had 7.1 to 9.7 Mg ha−1 less Douglas-fir biomass than the BO treatment. There was 1.5 to 20.5 Mg ha−1 greater Douglas-fir biomass in the AVC treatment than in the IVC treatment at all sites. Douglas-fir carbon and nitrogen biomass were consistently lower in the WT treatment, but there were no significant changes in overall site nutrient pools. The AVC treatment resulted in greater Douglas-fir nutrient pools yet there was a net loss in site calcium, magnesium, and potassium due to lower forest floor and soil base cation pools. While WT removals did not significantly affect site nutrition, the decrease in Douglas-fir biomass at all sites and increase in invasive Scotch broom (Cytisus scoparius (L.) Link) biomass at Matlock suggests that the standard practice of retaining harvest residuals is beneficial. The use of intensive vegetation control to improve Douglas-fir biomass and nutrition must be balanced with retaining soil base cations.
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Ross, Darrell W., Bruce B. Hostetler, and John Johansen. "Douglas-Fir Beetle Response to Artificial Creation of Down Wood in the Oregon Coast Range." Western Journal of Applied Forestry 21, no. 3 (2006): 117–22. http://dx.doi.org/10.1093/wjaf/21.3.117.
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Abstract Douglas-fir beetle populations were monitored before and after thinning and felling of trees to create down wood in an 88-year-old Douglas-fir plantation in the Oregon Coast Range. Treatments included an unthinned control, thinning to a target of 75 trees/ha, and thinning to a target of 150 trees/ha. Actual mean tree densities on the plots after thinning were 406, 102, and 154, for the control, 75 trees/ha, and 150 trees/ha treatments, respectively. Fifty trees/ha were felled and left on all thinned plots to create down wood for ecological values. Catches in pheromone-baited traps indicated that the local beetle population increased for 1 year in response to felling and leaving large diameter trees in partial shade. Douglas-fir beetle entrance holes and brood were significantly more abundant on the sides of felled trees and wood borers were significantly more abundant on the upper surface suggesting that treatments that provide maximum exposure of felled trees will create the least favorable habitat for Douglas-fir beetles. However, there were no differences in Douglas-fir beetle entrance holes or brood densities in felled trees between the two thinning intensities. Douglas-fir beetle-caused tree mortality was significantly higher on thinned plots with residual felled trees compared with unthinned controls, although infestation levels were low on all plots (<2 trees/ha). The small increase in beetle-caused tree mortality associated with leaving felled trees would be unlikely to interfere with resource management objectives. These results are applicable to mature, managed forests west of the Cascades with relatively low Douglas-fir beetle populations. In different regions and stand types, or under different environmental conditions, beetle populations could increase to higher densities, remain at high densities longer, and cause higher levels of tree mortality. West. J. Appl. For. 21(3):117–122.
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Emmingham, Wm, Rick Fletcher, Stephen Fitzgerald, and Max Bennett. "Comparing Tree and Stand Volume Growth Response to Low and Crown Thinning in Young Natural Douglas-fir Stands." Western Journal of Applied Forestry 22, no. 2 (2007): 124–33. http://dx.doi.org/10.1093/wjaf/22.2.124.
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Abstract We consider tree and stand response to low, crown, and no thinningof well-differentiated, naturally regenerated even-aged Douglas-firstands over 15 years on a moderately productive Cascade Mountains siteand over 10 years on a highly productive Oregon Coast Range site.Regardless of treatment, trees in dominant and codominant crown classescontinued growing at preinitiation rates and contributed 92–100% ofstand growth 5–15 years later. Most leave trees in suppressed crownclasses died during the first 10 years and suppressed and intermediatecrown classes contributed little to stand growth because survivorscontinued to grow slowly. Low thinning remains the most reliablethinning method for increasing stand volume in high-quality trees.Crown or selection thinning may be used to achieve certain objectivesif managers carefully use information about response of trees invarious crown classes. Growth rates of residual stands will depend onthe amount of residual growing stock and the degree to which it iscomprised of vigorously growing dominant and codominant trees.Residual subordinate trees may provide snags but few living trees insmall-diameter classes. Implications for management of the Douglas-firare discussed.
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Mainwaring, Douglas B., Douglas A. Maguire, Alan Kanaskie, and Jeff Brandt. "Growth responses to commercial thinning in Douglas-fir stands with varying severity of Swiss needle cast in Oregon, USA." Canadian Journal of Forest Research 35, no. 10 (2005): 2394–402. http://dx.doi.org/10.1139/x05-164.
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Concern has risen about the degree to which Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands with severe infections of Swiss needle cast (SNC) respond to thinning. A retrospective study was established in the fall of 2001 to assess the growth of Douglas-fir stands that were commercially thinned between 4 and 10 years ago. Current SNC infection levels in these stands ranged from severe to very light. Past volume and basal area growth declined with increasing severity of SNC, as measured by current foliage retention and crown length / sapwood ratio. As has been observed in many other studies, thinning to lower residual stock reduced stand level growth; however, individual tree growth increased with lower residual stand density. The ratio of growth in successive periods and analysis of annual basal area growth since thinning suggested that trees did respond to thinning, although less so as SNC increased. A positive response to thinning, regardless of infection level, was confirmed by an analysis of annual trends in basal area growth over the first 5 years after thinning.
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Garber, Sean, Tzeng Yih Lam, and Douglas A. Maguire. "Growth and Mortality of Residual Douglas-Fir after Regeneration Harvests under Group Selection and Two-Story Silvicultural Systems." Western Journal of Applied Forestry 26, no. 2 (2011): 64–70. http://dx.doi.org/10.1093/wjaf/26.2.64.
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Abstract Complex management objectives for many publicly owned Douglas-fir forests have prompted renewed interest in silvicultural systems other than clearcutting. The College of Forestry Integrated Research Project at Oregon State University was implemented to test for differences in economic, biological, and human responses to group selection and two-story silvicultural systems. Three separate blocks were established and treated between 1989 and 1991. Trees were measured immediately after the harvest treatments (1991 or 1992) and after the 2004 growing season. Responses of residual overstory trees to initial group selection and two-story treatments were tested relative to untreated controls units in terms of (1) gross basal area and stem volume growth of all residual trees and of the 10 largest trees per acre; (2) gross basal area and stem volume growth conditional on initial basal area and stem volume, respectively, of all residual trees and of the 10 largest trees per acre; and (3) mortality of all overstory trees. Basal area and volume growth were greatest in the control and least in the two-story treatment, but volume growth conditional on initial volume did not differ significantly among treatments. Mortality was significantly greater in the two-story treatment. Overstory growth release in residual Douglas-fir may require 10 years or more to appear after regeneration cuts on some sites, and the possibility of increased overstory mortality complicates attainment of desired long-term structure under two-story silvicultural systems.
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Acker, S. A., E. K. Zenner, and W. H. Emmingham. "Structure and yield of two-aged stands on the Willamette National Forest, Oregon: implications for green tree retention." Canadian Journal of Forest Research 28, no. 5 (1998): 749–58. http://dx.doi.org/10.1139/x98-039.
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Green tree retention, a practice based on ecosystem science, has been integrated into forest management as a working hypothesis, requiring research and monitoring to quantify its effects. We undertook a retrospective study of natural, two-aged forest stands on the Willamette National Forest to provide preliminary estimates of the effects of green tree retention on forest structure and yield. Fourteen stands in the western hemlock (Tsuga heterophylla (Raf.) Sarg.) zone (mostly dominated by Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco) were sampled using adjacent, paired plots: one with residual trees over a younger cohort (median age of younger cohort, 97 years) and one with only the younger cohort. The younger cohorts all had much higher densities of trees than typical of local Douglas-fir plantations. Basal area, volume, and mean annual increment (MAI) of the younger cohort all declined with increasing residual tree basal area. These relationships were best described by curvilinear models; the greatest effect per unit of residual tree basal area occurred at low residual tree levels (5-10 m2/ha). For 10 m2/ha residual tree basal area (equivalent to about 12 average (diameter at breast height 105 cm) residual trees per hectare), we predicted a 26% decline in younger cohort MAI (95% confidence interval: -30% to -22%).
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Thomson, A. J., and Y. A. El-Kassaby. "Trend surface analysis of a Douglas-fir provenance–progeny transfer test." Canadian Journal of Forest Research 18, no. 5 (1988): 515–20. http://dx.doi.org/10.1139/x88-075.
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Spatial variability in heights of 8-year-old Douglas-fir in a IUFRO provenance–progeny transfer test was analyzed using trend surface analysis to differentiate genetic and environmental effects on tree height. The test installation was located in the University of British Columbia Research Forest, and was a randomized incomplete block design with three replications. Only the 25 provenances that were replicated in each block and had a balanced data set (eight families, five trees per family) were used. Trends were fitted to the average height of each replicate of each provenance, and also to the average size of the largest and smallest families per replicate. Interpretation was based on the assumption that the effects of microsite (mainly grass invasion of one block) were defined by the trend surface, while genetic effects were represented by the residuals from the trend. The data had previously been analyzed by ANOVA methods and these results were contrasted with the results using trend surface analysis. Trend surface analysis generally gave results similar to ANOVA, but in some cases resulted in different conclusions. Additional insights into the interaction of genotype and environment were obtained. Trend surface analysis is proposed as a useful supplement to analysis of variance in provenance transfer studies. Potential problems in using the method are discussed.
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Fraser, R. G., J. D. Beale, and R. J. Nevill. "Reduction of Phellinusweirii inoculum in Douglas-fir stumps by the fumigant Telone ll-B." Canadian Journal of Forest Research 25, no. 1 (1995): 63–68. http://dx.doi.org/10.1139/x95-008.
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Two dosages of Teione II-B (1,3-dichloropropene) at 3.4 and 6.7 mL/kg of stump and root biomass were tested to determine the efficacy in reducing Phellinusweirii (Murr.) Gilb. inoculum in infected Douglas-fir, Pseudotsugamenziesii (Mirb.) Franco, stumps. After 21 months, both doses of Teione II-B proved equally effective and significantly (p < 0.05) reduced residual P. weirii mycelium in infected roots. Fumigation reduced residual endotrophic P. weirii in the large-diameter root classes nearest the stump, but survival of the fungus was less affected with increasing distance from the stump and in the smaller root diameter classes. Treated stumps also had significantly (p < 0.05) fewer roots with ectotrophic mycelium than untreated stumps. Four weeks after application, soil samples taken near treated stumps revealed no evidence of the fumigant. These findings suggest that application of Teione II-B could be used as an effective control measure for P. weirii.
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Gartner, Barbara L., Eric M. North, G. R. Johnson, and Ryan Singleton. "Effects of live crown on vertical patterns of wood density and growth in Douglas-fir." Canadian Journal of Forest Research 32, no. 3 (2002): 439–47. http://dx.doi.org/10.1139/x01-218.
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It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production of the two types of wood. Foresters commonly assume the bole of softwoods produces juvenile wood within the crown and mature wood below. We tested that assumption by comparing growth ring areas and widths and wood density components of the outer three growth rings in disks sampled from different vertical positions of 34-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. The 18 trees were sampled from one site and had a wide range of heights to live crown. Most of the variance (6393%) in wood characteristics (growth ring area: total, earlywood, latewood; growth ring width: total, earlywood, latewood; latewood proportion: by area, width; and ring density: total, earlywood, latewood) was due to within-tree differences (related to age of the disk). Stepwise regression analysis gave us equations to estimate wood characteristics, after which we analyzed the residuals with a linear model that included whether a disk was within or below the crown (defined as the lowest node on the stem with less than three live branches). After adjusting for tree and disk position, only 210% of the residual variation was associated with whether the disk was in or out of the live crown. There were no statistically significant differences at p = 0.05 between a given disk (by node number) in versus out of the crown for any of the factors studied. Moreover, the wood density characteristics were not statistically significant at p = 0.30. This research suggests that there was no effect of the crown position on the transition from juvenile to mature wood as judged by wood density. Therefore, we found no evidence to support the concept that tree spacing and live-branch pruning have a significant effect on the cambial age of transition from juvenile to mature wood in Douglas-fir trees of this age.
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Filip, Gregory M., Craig L. Schmitt, and Kristen L. Chadwick. "Incidence of Heterobasidion annosum in Mixed-Conifer Natural Regeneration Surrounding Large True Fir Stumps 20–25 Years after Harvesting in Northeastern Oregon." Western Journal of Applied Forestry 21, no. 4 (2006): 178–84. http://dx.doi.org/10.1093/wjaf/21.4.178.
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Abstract High-elevation true fir stands on federal lands have a long history of selective harvesting. In 1989 a high frequency (89%) of Heterobasidion annosum, the cause of annosus root disease, was found in residual true fir stumps (mean, 20-in. diameter) cut 5–9 years earlier in northeast Oregon. In 2004, H. annosum was found at the stump surface of 29% of the natural conifer regeneration (mean, 18 years) within 20 ft of infected residual stumps. A total of 16 of 122 (13%) live saplings had H. annosum–caused stain or decay. Only 3% of 126 sample trees, however, were dead and infected by H. annosum. Infection was confirmed in 62% of decayed trees, 33% of stained trees, and 22% of trees with no visible stain or decay at the stump surface. Only 3 of 122 living saplings showed typical root disease crown symptoms (chlorosis), but only one of these had H. annosum. Only 1 of 16 live saplings with H. annosum–caused stain or decay was chlorotic. Incidence of infection was 44% in Engelmann spruce (7 of 16 trees), 31% in Douglas-fir (5 of 16 trees), 31% in subalpine fir (4 of 13 trees), and 27% in grand fir (21 of 77 trees). The S-type of H. annosum was confirmed in a sampled grand fir. There were no significant differences between H. annosum–infected and apparently healthy trees regarding live crown ratio and distance from infected residual stumps. Infected trees, however, were significantly (P = 0.025) larger in diameter than apparently healthy trees. The dynamics of H. annosum infection in spruce and Douglas-fir in northeast Oregon are discussed as well as treating true fir stumps with boron-containing products to prevent stump infection by H. annosum. West. J. Appl. For. 21(4):178–184.
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Han, Han-Sup, and Loren D. Kellogg. "Damage Characteristics in Young Douglas-Fir Stands from Commercial Thinning with Four Timber Harvesting Systems." Western Journal of Applied Forestry 15, no. 1 (2000): 27–33. http://dx.doi.org/10.1093/wjaf/15.1.27.
Full textAbstract:
Abstract Damage to residual trees from commercial thinning was characterized and compared among four common harvesting systems in western Oregon: tractor, cut-to-length, skyline, and helicopter. Six young (30- to 50-yr-old) Douglas-fir (Pseudotsuga menziesii) stands with various residual densities were studied: Scarring was the most typical damage to crop trees, accounting for 90% of the total damage in most cases. Damage levels greatly decreased as the minimum scar size that defines damage was increased. Scarring by ground-based systems was more severe: scars were larger, and gouge and root damage were more prevalent than in skyline and helicopter systems. Damaged trees were concentrated within 15 ft of skid trails or skyline corridor centerlines. In the cut-to-length system, the harvester caused more wounding (70%) to crop trees than did the forwarder (30%), but forwarder scars were larger and sustained severe gouging. Recommendations for minimizing stand damage are included. West. J. Appl. For. 15(1):27-33.
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Nigh, Gordon D., and Matthew G. E. Mitchell. "Development of Height-Age Models for Estimating Juvenile Height of Coastal Douglas-Fir in British Columbia." Western Journal of Applied Forestry 18, no. 3 (2003): 207–12. http://dx.doi.org/10.1093/wjaf/18.3.207.
Full textAbstract:
Abstract Douglas-fir (Pseudotsuga menziesii var. menzeisii) is an important and abundant tree species in coastal British Columbia. Juvenile height estimates are important for management prescriptions and decisions involving regenerating stands. We used 100 plots to investigate the juvenile height growth of coastal Douglas-fir. The growth patterns of the sample trees were observed by felling and splitting them longitudinally and measuring the height of the annual nodes from the point of germination. Sixty-four plots were used to develop a height model as a function of total age and site index. The Chapman-Richards, Gompertz, and modified exponential and power models were fit using nonlinear least squares regression. The models were tested with the remaining 36 plots. The modified exponential and power equation was the best fitting of the three models. None of the models met the regression assumption of independently normally distributed residuals with a mean of zero and a constant variance. The modified exponential and power model was further analyzed using the complete data set by fitting height growth and incorporating a model for serial correlation in the error term to improve the statistical properties of the model. West. J. Appl. For. 18(3):207–212.
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Maguire, Douglas A., and David W. Hann. "Constructing models for direct prediction of 5-year crown recession in southwestern Oregon Douglas-fir." Canadian Journal of Forest Research 20, no. 7 (1990): 1044–52. http://dx.doi.org/10.1139/x90-139.
Full textAbstract:
Crown recession rates were estimated by branch mortality dating on 357 sectioned Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stems from temporary plots. Numerous nonlinear, logarithmic, and gamma-theory generalized linear models were developed for predicting 5-year crown recession across a range in tree, stand, and site conditions. Residual analyses and indices of fit demonstrated that a multiplicative model with lognormal errors was the most appropriate model form. The recommended logarithmic model predicts crown recession from current crown ratio, total height, breast height age, height growth, and crown competition factor. Data from southwestern Oregon indicate that within a given stand, trees with midsized crown ratios experience the most rapid crown recession.
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Roberts, Scott D., Constance A. Harrington, and Thomas A. Terry. "Harvest residue and competing vegetation affect soil moisture, soil temperature, N availability, and Douglas-fir seedling growth." Forest Ecology and Management 205, no. 1-3 (2005): 333–50. http://dx.doi.org/10.1016/j.foreco.2004.10.036.
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Maguire, Douglas A., and João L. F. Batista. "Sapwood taper models and implied sapwood volume and foliage profiles for coastal Douglas-fir." Canadian Journal of Forest Research 26, no. 5 (1996): 849–63. http://dx.doi.org/10.1139/x26-093.
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Sapwood dimensions lend insight into the functional and ecophysiological structure of trees and can therefore be profitably applied in various types of growth analyses and simulation models. Ten taper models were fitted to sapwood data from the stems of 134 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees and were compared by various fit statistics, residual behavior, and validation performance on 21 additional trees. The recommended model was a variable exponent model with six parameters and three basic tree-level predictors: diameter, height, and height to crown base. The resulting equation can be applied for estimating sapwood area at crown base, leaf area, sapwood volume, and vertical foliage distribution on standing trees. Ten sample plots are examined to demonstrate that sapwood taper models allow more explicit portrayal of stand structure in dimensions that have a direct functional link to various growth and developmental processes.
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Oren, Ram, Walter G. Thies, and Richard H. Waring. "Tree vigor and stand growth of Douglas-fir as influenced by laminated root rot." Canadian Journal of Forest Research 15, no. 5 (1985): 985–88. http://dx.doi.org/10.1139/x85-156.
Full textAbstract:
Total stand sapwood basal area, a measure of competing canopy leaf area, was reduced 30% by laminated root rot induced by Phellinusweirii (Murr.) Gilb. in a heavily infected 40-year-old coastal stand of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) compared with that of a similar uninfected stand. Annual basal area increment per unit of sapwood area, an index of tree vigor, was expected to increase in uninfected trees in the infected stand as surrounding trees died from root rot; vigor of the uninfected trees did increase by an average of 30%, offsetting the reduction in canopy leaf area. This increase, although less than might be expected in an evenly spaced thinned stand, was sufficient to maintain stand basal area growth at levels similar to those of unthinned forests. These findings indicate that increased growth by residual trees must be taken into account when the impact of disease-induced mortality on stand production is assessed.
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Yang, Mingyan, Hairui Ji, and J. Y. Zhu. "Batch Fermentation Options for High Titer Bioethanol Production from a SPORL Pretreated Douglas-Fir Forest Residue without Detoxification." Fermentation 2, no. 4 (2016): 16. http://dx.doi.org/10.3390/fermentation2030016.
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Homann, Peter S., Bruce A. Caldwell, H. N. Chappell, Phillip Sollins, and Chris W. Swanston. "Douglas-fir soil C and N properties a decade after termination of urea fertilization." Canadian Journal of Forest Research 31, no. 12 (2001): 2225–36. http://dx.doi.org/10.1139/x01-162.
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Chemical and microbial soil properties were assessed in paired unfertilized and urea fertilized (>89 g N·m2) plots in 13 second-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands distributed throughout western Washington and Oregon. A decade following the termination of fertilization, fertilized plots averaged 28% higher total N in the O layer than unfertilized plots, 24% higher total N in surface (05 cm) mineral soil, and up to four times the amount of extractable ammonium and nitrate. Decreased pH (0.2 pH units) caused by fertilization may have been due to nitrification or enhanced cation uptake. In some soil layers, fertilization decreased cellulase activity and soil respiration but increased wood decomposition. There was no effect of fertilization on concentrations of light and heavy fractions, labile carbohydrates, and phosphatase and xylanase activities. No increase in soil organic C was detected, although variability precluded observing an increase of less than ~15%. Lack of a regionwide fertilization influence on soil organic C contrasts with several site-specific forest and agricultural studies that have shown C increases resulting from fertilization. Overall, the results indicate a substantial residual influence on soil N a decade after urea fertilization but much more limited influence on soil C processes and pools.
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Zamani, Arezoo, Rona N. Sturrock, Abul K. M. Ekramoddoullah, Jun Jun Liu, and Xueshu Yu. "Gene Cloning and Tissue Expression Analysis of a PR-5 Thaumatin-Like Protein in Phellinus weirii-Infected Douglas-Fir." Phytopathology® 94, no. 11 (2004): 1235–43. http://dx.doi.org/10.1094/phyto.2004.94.11.1235.
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In western North America, Douglas-fir (Pseudotsuga menziesii) is the most economically important conifer species susceptible to laminated root rot caused by Phellinus weirii. While attempting to internally sequence an endochitinase found to be up-regulated in P. weirii-infected Douglas-fir roots, we obtained overlapping peptide fragments showing 28% similarity with a PR-5 thaumatin-like protein (TLP) designated PmTLP (Pm for Pseudotsuga menziesi). A rabbit polyclonal antibody was reared against a synthetic peptide composed of a 29-amino-acid-long, conserved, internal sequence of PmTLP and purified by immunoaffinity. Western immunoblot analysis of infected roots of 24-year-old coastalfir showed significantly higher amounts of PmTLP (P < 0.01) closest to the point of P. weirii inoculation and infection than in uninfected regions of the same root. The antibody was also used to screen for PmTLP in roots of 25-year-old interior Douglas-firs naturally infected with a related pathogen, Armillaria ostoyae, and results showed significantly higher levels of PmTLP in bark tissues adjacent to infection (P < 0.05) than in uninfected tissue. Using polymerase chain reaction (PCR)-based cloning, the cDNA of PmTLP was shown to have a 702-bp open reading frame with a signal peptide cleavage site at 155 bp corresponding to a 29-amino-acid-long residue prior to the start of the N-terminal. Based on the deduced amino acid sequence, the molecular mass of the putative PmTLP was calculated to be 21.0 kDa with an isoelectric point of 3.71. Alignment analysis of PmTLP cDNA with a representative genomic DNA PCR sequence showed presence of one intron of variable size, within the coding region. The induction of PmTLP at the site of root infection and its presence in needle tissue suggests a general role for this protein in adaptation to stress and may be part of an integrated defense response initiated by the host to impede further pathogen spread.
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Chiang, Vincent L., and Masamitsu Funaoka. "The Formation and Quantity of Diphenylmethane Type Structures in Residual Lignin during Kraft Delignification of Douglas-Fir." Holzforschung 42, no. 6 (1988): 385–91. http://dx.doi.org/10.1515/hfsg.1988.42.6.385.
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Konkler, Matthew J., Jed Cappellazzi, Connie S. Love, Camille Freitag, and Jeffrey J. Morrell. "Performance of Internal Remedial Treatments on Douglas-Fir Poles: A Large-Scale Field Trial." Forest Products Journal 69, no. 4 (2019): 289–304. http://dx.doi.org/10.13073/fpj-d-19-00030.
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Abstract Internal decay is a common problem in poles or timbers of thin sapwood species. Several internal treatments have been developed to arrest this attack, and these systems are widely used in North America. Although these treatments have been evaluated in numerous independent field trials, there is no single test of all treatments. The objective of this study was to assess the chemical distribution and fungal colonization in Douglas-fir poles treated with each of 13 different internal remedial treatments over a 10-year period. Metam sodium treatments provided the shortest protective period, with little evidence of residual chemical 3 years after treatment. Methylisothiocyanate (MITC) in pure form provided a very high initial flush of active ingredient and a longer protective period extending from 5 to 8 years after treatment. Dazomet, which must decompose to produce MITC, took slightly longer to reach effective levels, but was still present at effective levels 10 years after treatment. Chloropicrin, which has strong interactions with wood, was associated with the highest chemical levels after 10 years. Borates took longer to reach effective levels in the poles and their protective zone was narrower than the fumigants, but boron was still present at effective levels 10 years after application. The results illustrate the different properties provided by each treatment, but also show that all tested remedial treatments were effective within certain limitations.
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Johnson, Morris C., Maureen C. Kennedy, and David L. Peterson. "Simulating fuel treatment effects in dry forests of the western United States: testing the principles of a fire-safe forest." Canadian Journal of Forest Research 41, no. 5 (2011): 1018–30. http://dx.doi.org/10.1139/x11-032.
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We used the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) to simulate fuel treatment effects on 45 162 stands in low- to midelevation dry forests (e.g., ponderosa pine ( Pinus ponderosa Dougl. ex. P. & C. Laws.) and Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) of the western United States. We evaluated treatment effects on predicted post-treatment fire behavior (fire type) and fire hazard (torching index). FFE-FVS predicts that thinning and surface fuel treatments reduced crown fire behavior relative to no treatment; a large proportion of stands were predicted to transition from active crown fire pre-treatment to surface fire post-treatment. Intense thinning treatments (125 and 250 residual trees·ha–1) were predicted to be more effective than light thinning treatments (500 and 750 residual trees·ha–1). Prescribed fire was predicted to be the most effective surface fuel treatment, whereas FFE-FVS predicted no difference between no surface fuel treatment and extraction of fuels. This inability to discriminate the effects of certain fuel treatments illuminates the consequence of a documented limitation in how FFE-FVS incorporates fuel models and we suggest improvements. The concurrence of results from modeling and empirical studies provides quantitative support for “fire-safe” principles of forest fuel reduction (sensu Agee and Skinner 2005. For. Ecol. Manag. 211: 83–96).
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Crotteau, Justin S., and Christopher R. Keyes. "Restoration Treatments Improve Overstory Tree Resistance Attributes and Growth in a Ponderosa Pine/Douglas-Fir Forest." Forests 11, no. 5 (2020): 574. http://dx.doi.org/10.3390/f11050574.
Full textAbstract:
Research Highlights: This study provides much needed insight into the development of resistance to disturbance and growth dynamics of overstory trees in response to restoration-based fuel reduction, and will be useful to scientists and managers attempting to better grasp the relative merits of restoration treatment types. Background and Objectives: Restoration-based fuel reduction treatments are common in dry, fire-prone forests of the western United States. The primary objective of such treatments is to immediately reduce a stand’s crown fire hazard. However, the impact of these treatments on residual trees is relevant to assess their longevity and resistance to future disturbances. In this study, we evaluate the effects of restoration on retained overstory ponderosa pine (Pinus ponderosa Lawson & C. Lawson) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees in western Montana, where treatments were experimentally implemented 13 years prior as part of the national Fire and Fire Surrogate study. Materials and Methods: We examined tree attributes in response to the following replicated treatments: thin-only, burn-only, thin + burn, and a no-action control. We analyzed three different tree attributes that confer resistance to common disturbances: height-to-diameter ratio (resistance to wind), bark thickness (resistance to surface fire), and growth efficiency (resistance to bark beetles). Results: Our models suggest that thinning (with or without burning) alters tree attributes relative to the control in a manner that may increase tree resistance to wind and snow breakage, surface fire, and biotic agents such as bark beetles. Further analysis of annual growth of ponderosa pine and Douglas-fir varied by treatment type: thinning-based restoration (thin-only and thin + burn) increased diameter growth for both species, crown length and width in ponderosa pine, and crown length in Douglas-fir relative to unthinned treatments. Burning (burn-only and thin + burn) did not significantly affect tree growth relative to unburned treatments. Conclusions: While low-severity prescribed burning treatments are often used for restoration and have various ecosystem benefits, this study demonstrates that thinning (alone or in addition to burning) produces more measureable, beneficial results to overstory tree disturbance resistance metrics and growth.
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O'Hara, K. L. "Stand structure and growing space efficiency following thinning in an even-aged Douglas-fir stand." Canadian Journal of Forest Research 18, no. 7 (1988): 859–66. http://dx.doi.org/10.1139/x88-132.
Full textAbstract:
The growth of individual trees from four thinning treatments in a 64-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was analyzed to determine desirable residual stand structures after thinning. Dominant and codominant trees had the highest individual tree stem volume growth rates over the previous 5 years, and accounted for most stand volume growth in thinned and unthinned stands. Two measures of growing space, crown projection area and sapwood basal area (a surrogate for leaf area), were used to measure how efficiently individual trees used their growing space. Crown classes were useful in characterizing growing space efficiency (volume growth per unit of growing space) only in the unthinned treatment. In thinned treatments, tall trees with medium-sized crowns were most efficient, while in the unthinned treatment, tall trees with relatively large crowns were most efficient. A large crown in an unthinned stand was comparable in size to a medium-sized crown in a thinned stand. Results suggest growing space is not limiting individual tree growth in thinned stands and that thinning to a particular stand structure is more appropriate than thinning to a particular level of stand density.