Articles+ start Author "Todoroki, Christine L."

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1. Validation of models predicting modulus of elasticity in Douglas-fir trees, boles, and logs [2016]

  • Todoroki, Christine L. and Lowell, Eini C.
  • New Zealand journal of forestry science, 2016; v.46 n.11:15p

2. Radial variation in selected wood properties of three cypress taxa [2015]

  • Todoroki, Christine L.
  • New Zealand journal of forestry science, 2015; v.45 n.24:14p

3. Maps and models of density and stiffness within individual Douglas-fir trees [2012]

  • Todoroki, Christine L.
  • New Zealand journal of forestry science, 2012; v.42:p.1-13

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5. Observations of parasitoid behaviour in both no‐choice and choice tests are consistent with proposed ecological host range [2021]

  • Withers, Toni M., Allen, Geoff R., Todoroki, Christine L., Pugh, Andrew R., and Gresham, Belinda A.
  • Entomologia experimentalis et applicata. 169(1):97-110

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7. Lumber volume and value from elliptical western hemlock logs [2007]

  • TODOROKI, Christine L, MONSERUD, Robert A, and PARRY, Dean L
  • Forest products journal. 57(7-8):76-82
Subjects
Forestry, silviculture, Foresterie, sylviculture, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Bois. Papiers. Non tissés, Wood. Paper. Non wovens, Bois, Wood, Propriétés et essais, Properties and testing, Traitements mécaniques et séchage, Mechanical woodworking and drying, Dégradation et protection, Degradation and preservation, Bois résineux, Softwood, Madera de coníferas, and Spermatophyta
Abstract
The effect of log ovality and orientation on lumber yield and value recovery was examined through sawing simulation. Ovality was modeled on digitized western hemlock (Tsuga heterophylla) logs by altering the ratio of minor to major axes on a given cross section from 1.00 (circular) to 0.80 (oval) in 0.05 unit decrements, while holding cross sectional area and volume constant. The log models were cant-sawn in the AUTOSAW simulator across the full range of rotational settings and lumber was tallied and priced according to WWPA grade. Responses (lumber yield and value recovery) were normalized relative to those of the circular logs at their initial orientation to eliminate effects due to the large range in log diameters. Maximum responses were calculated and the orientations attaining those maxima recorded. Log ovality was, contrary to the common assumption, beneficial to lumber yield when the log was sawn at the optimum orientation. A 3.2 percent increase in yield relative to the circular logs was recorded for the optimally rotated logs with an ellipticity ratio of 0.80 (95% CI, 1.1% to 5.3%). With ellipticity 0.90, approximately equal to the average for western hemlock, the increase was 3.4 percent (95% CI, 1.8% to 4.9%). Ovality was neither beneficial nor detrimental to maximum value recovery; differences were not significant. Optimal lumber yield occurred more frequently at 90° and 270°, equivalent to primary sawing parallel to the major axis. However, value recovery fluctuated considerably, even with circular logs, and there was no unique angle at which maximum value recovery occurred.

8. Predicting internal lumber grade from log surface knots : Actual and simulated results [2005]

  • TODOROKI, Christine L, MONSERUD, Robert A, and PARRY, Dean L
  • Forest products journal. 55(6):38-47
Subjects
Forestry, silviculture, Foresterie, sylviculture, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Bois. Papiers. Non tissés, Wood. Paper. Non wovens, Bois, Wood, Propriétés et essais, Properties and testing, Traitements mécaniques et séchage, Mechanical woodworking and drying, Coniferales, Gymnospermae, Spermatophyta, Bois résineux, Softwood, Madera de coníferas, Effet dimensionnel, Size effect, Efecto dimensional, Etude théorique, Theoretical study, Estudio teórico, Morphologie, Morphology, Morfología, Pseudotsuga menziesii, Sciage, Sawing, Aserradura, Simulation numérique, Numerical simulation, Simulación numérica, Usinage, Machining, Mecanizado, Noeud bois, and Wood knot
Abstract
The purpose of this study was threefold: 1) compare actual with simulated lumber yields; 2) examine the effect of measurement errors associated with knot angles and morphology, on lumber grade; and 3) investigate methods for predicting lumber quality within unsawn logs from surface knots. Twenty-eight Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) logs were measured, mapped, sawn, and the lumber dried and graded. A corresponding set of digital log models was developed. Further sets that altered knot azimuth (within measurement error), rake (according to branch distributions), and branch morphology (live or dead) were generated. All log models were processed in the sawing simulator AUTOSAW and the simulated lumber with knot defects was graded to Western Wood Products Association criteria (American Lumber Standards). The simulations showed that lumber grade is sensitive to knot angle, in particular azimuth, and even more so, to morphology. However, other factors not represented in this study have an additional effect on lumber grade. An index, Grade Average, was developed to quantify log quality in terms of lumber grades. In general Grade Average decreased with increasing mean knot diameter. This tendency was stronger for simulated grade yield (r2 ranging from 0.74 to 0.76) than actual (r2 = 0.26). Grade Average tended to over-predict when there were fewer than 10 surface knots, and to under-predict with smaller diameter logs. The relationship between actual and simulated Grade Average was quite poor (r2 ranging from 0.10 to 0.11). These results suggest that knowledge of the log surface knots alone is not enough to accurately predict internal lumber grade.

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10. Linking acoustic velocity of standing Douglas-fir trees to veneer stiffness: a tree-log-product study across thinning treatments [2014]

  • Lowell, Eini C, Todoroki, Christine L, Dykstra, Dennis P, and Briggs, David G
  • New Zealand Journal of Forestry Science. December 2014 44(1):1-16

11. Comparing timber and lumber from plantation and natural stands of ponderosa pine [2009]

  • Lowell, Eini C., Todoroki, Christine L., and Thomas, Ed
  • Western journal of applied forestry, 2009 July, v. 24, no. 3, p. 137-143.
Subjects
lumber, trees, knots, age structure, simulation models, and surface area
Abstract
Data derived from empirical studies, coupled with modeling and simulation techniques, were used to compare tree and product quality from two stands of small-diameter ponderosa pine trees growing in northern California: one plantation, the other natural. The plantation had no management following establishment, and the natural stand had no active management. Fifty trees of similar diameter classes were selected from each site, measured, bucked into logs, and sawn into boards, and the boards were scanned for defects. Trees from the plantation stand demonstrated less variability in tree height, crown length, and age structure. The plantation trees were on average 4 years younger than their natural cohorts, yet for all but the smallest diameter there were no significant differences between mean tree height or crown length. Predicted merchantable volumes differed significantly for the largest diameter class. Merchantable volume was estimated to be 5% greater for the plantation trees than for the natural stand trees. More logs were bucked from the plantation stands, resulting in greater lumber production and greater value overall. Butt logs from the plantation stand had an average of 9 whorls per log, whereas natural butt logs averaged 10 whorls per log. The most numerous defects, outnumbering knots and wane, were needle traces. These occupied some 31% of natural board surface area, in comparison with 19% for plantation boards. Given the shorter time frame required to grow plantation trees, the greater merchantable volumes, and more consumer-acceptable defects, plantation stands, even with a minimal level of management, offer greater product potential than natural stands.

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13. Linking acoustic velocity of standing Douglas-fir trees to veneer stiffness: a tree-log-product study across thinning treatments

  • Lowell, Eini C, Todoroki, Christine L, Dykstra, Dennis P, and Briggs, David G
Subjects
Modulus of elasticity, Wood density, Stand density, Tree breeding, Veneer, Acoustic velocity, Douglas-fir
Abstract
In general, trees with MOE exceeding the recommended tree breeding value of 11 GPa were of low taper and small diameter, suggesting that regimes with a lesser impact on taper and diameter, as demonstrated by Plot E, are worthy of further investigation.

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