bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative effectiveness of nutrient concentrations in living foliage and needle fall at predicting response of loblolly pine to N and P fertilization
Authors: Lea R. , Ballard R.
Published: January 2008

Concentrations of N, P, Ca, and Mg but not K in loblolly pine (Pinustaeda L.) needle fall were significantly correlated with their respective levels in both young and older living foliage; correlations were generally highest with levels in the older foliage. Tissue P concentrations were significantly correlated with 5-year response to P fertilization, while tissue N concentrations were poor predictors of response to N fertilization. No single tissue type exhibited any superiority at predicting fertilizer response. Needle fall was easier to collect than living foliage but showed greater within-site variation.
Biomass and growth of Populustremuloides in northeastern Alberta: estimates using hierarchy in tree size
Authors: Lleffers V. J. , Campbell J. S.
Published: January 2008

Biomass and growth (productivity) of Populustremuloides Michx. was determined from 20 × 20 m plots in 39 even-aged stands in northeastern Alberta. The diameters of all trees were measured at a 1.3-m height. In each stand, the periodic annual basal area increment (1977–1981) of 10–16 sample trees was proportional to the square of the diameter of each tree. This relationship was used to estimate the change in diameter of each tree in the stand for the 5-year period. The current biomass and the biomass per tree 5 years earlier were determined from an allometric equation of tree biomass versus diameter. A point estimate of growth over the last 5 years was determined by the difference between these values. Stands ranged from 23 to 57 years old, aboveground biomass from 37 to 156 t ha−1, and current rates of production from 1.5 to 5.2 t ha−1 year−1. Single tree cumulative biomass and growth were highest in low density and older stands. Stand biomass was highest in older stands but showed no relationship to stand density. Stand growth was not related to age, but was higher in more dense stands. There was no detectable reduction in growth near an SO2 source in the study area.
Monte Carlo simulation of white spruce regeneration after logging in interior Alaska
Authors: Fox John D. , Zasada John C. , Gasbarro Anthony F. , Veldhuizen Robert Van
Published: January 2008

Regeneration surveys on nine logged areas in the vicinity of Fairbanks, Alaska indicated low levels of white spruce (Piceaglauca (Moench.) Voss.) regeneration. In view of the limited field data, Monte Carlo simulation methods were used to estimate the probabilities of obtaining various levels of white spruce stocking by the 1st and 10th years after logging. The simple model developed, combined the irregular seed production of white spruce with a declining seedbed availability to estimate quadrat stocking (4-m2 plots). Results of simulation experiments indicated that the probability of achieving greater than 40% stocking with white spruce by the 10th postharvest year was 0.63. This result was sensitive to initial postharvest seedbed conditions and the frequency of good to excellent seed years and nonspruce revegetation rates. Both the field data and simulation results indicate the prospects of obtaining adequate white spruce restocking after timber harvest by unassisted natural regeneration were poor. However, simulation results also indicate that seedbed management may increase the probabilities of regeneration success significantly.
Responses of Douglas-fir trees to injection of chloropicrin
Authors: Goodell Barry S. , Helsing Guy G. , Graham Robert D.
Published: January 2008

The heartwood in each of eight decay-free Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees was injected with 125, 250, or 500 mL of the agricultural fumigant chloropicrin (nitrotrichloromethane). The trees were periodically inspected during 4 years to determine the extent of the phytotoxic response. Diffusion of fungistatic vapors within the heartwood and sapwood of the trees was monitored by closed-tube bioassay of increment cores. During the 1st year, all trees reacted adversely to the treatment, especially those of least diameter. Reaction was less severe in trees treated with smaller doses of fumigant. After 4 years, no continued, adverse response to treatment was apparent, and growth of all trees remained comparable to that of control trees. Fungistatic vapors were detected in the heartwood of the treated trees at some sites 1 and 2 m from the treatment zone. Additional experimentation using trees infected with decay is suggested.
Long-term responses of stem growth and leaf area to thinning and fertilization in a Douglas-fir plantation
Authors: Binkley Dan , Reid Paula
Published: January 2008

Within a 53-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantation, replicated thinning and fertilization plots were examined for responses in stem growth, leaf area, and stem growth per unit leaf area. Although measurements occurred 20–30 years after plot installation, substantial effects from the various treatment levels were still present. Thinning reduced leaf area of the stands but increased stem growth per unit of leaf area, resulting in little difference in stem growth per hectare over the 5-year measurement period (1977–1981). Fertilization increased both stand leaf area and stem growth per unit leaf area, and more than doubled 5-year stem growth per hectare. Consideration of the role of leaf area and stem growth per unit leaf area in determining stand treatment responses may account for much of the variation found among replicates of treatments or between studies on different sites.
Hazard rating of lodgepole pine stands to mountain pine beetle outbreaks in southcentral Oregon
Authors: Stuart John David
Published: January 2008

Stand structure and vigor variables were used to develop a model for predicting the development of a Dendroctonusponderosae Hopk. outbreak in climax Pinuscontorta Dougl. ex Loud. var. murrayana Grev. and Balf. stands in south central Oregon. Stepwise discriminant analysis indicated the significant predictor variables were quadratic mean diameter and the number of rings in the outermost centimetre of radial growth at breast height (p = 0.00001, canonical correlation coefficient = 0.77235). Ninety-three percent of the stands were correctly classified into their appropriate groups (attacked versus unattacked). None of the five indices of competition tested (i) Waring and Pitman's tree vigor index, (ii) Mahoney's periodic growth ratio, (iii) Krajicek's crown competition factor, (iv) Hegyi's competition index, and (v) Curtis's stand density index) were significant discriminators.
Variation in susceptibility to sweet fern rust among Pinuscontorta and P. banksiana
Authors: Hunt R. S. , Sickle G. A. Van
Published: January 2008

Cronartiumcomptoniae incidence was measured on 62 provenances of Pinusbanksiana and 77 provenances of P. contorta. Infection incidence varied among provenances in both hosts. Pinusbanksiana provenances beyond the geographic range of Comptoniaperegrina, and P. contorta provenances beyond the geographic range of Myricagale, were more susceptible than some provenances within the range of these alternate hosts. It is hypothesized that selection pressure is important in maintaining resistance to C. comptoniae.
Changes in isoenzyme patterns during imbibition and germination of lodgepole pine (Pinuscontorta var. latifolia)
Authors: Pitel J. A. , Cheliak W. M. , Wang B. S. P.
Published: January 2008

Isoenzymes of esterase (EST), glutamate-oxaloacetate transaminase (GOT), leucine aminopeptidase (LAP), and peroxidase (PER) were examined following various periods of imbibition and germination of lodgepole pine (Pinuscontorta var. latifolia Engelm.) seeds. The acidic and basic isoenzymes of embryos, and roots and shoots of germinating seedlings were analyzed by polyacrylamide gel electrophoresis. One major band of EST disappeared with imbibition, while some minor bands appeared and disappeared with imbibition and germination. Comparison of the roots and shoots after 7 and 14 days of germination showed several tissue-specific differences. The number of bands of GOT increased with imbibition and germination. The levels of activity of three isoenzymes differed between the root and shoot tissues. One band of LAP disappeared with imbibition. The levels of activity of two bands varied between the root and shoot tissues. The number of bands of PER increased dramatically following imbibition and germination. Also, many tissue-specific differences were observed between root and shoot tissues.
Floristic composition before and after prescribed fire on a jack pine clear-cut site innorthern lower Michigan
Authors: Abrams Marc D. , Dickmann Donald I.
Published: January 2008

Permanent frequency and cover plots were established and monitored for 3 years on a recent jack pine (Pinusbanksiana Lamb.) clear-cut in northern lower Michigan to characterize vegetational changes on burned and unburned blocks. Community data were also recorded from an adjacent mature jack pine stand. Vaccinium dominated (30% cover) the mature jack pine understory, whereas at the time of burning, the clear-cut site (3 year old) was dominated (33% cover) by Carexpensylvanica Lam. Two years after fire, burned blocks were significantly different from unburned blocks in terms of total cover, cover of grasses and sedges, and number of perennial forbs. Egler's initial floristic composition model was supported by the fact that every species in the mature jack pine understory was present on either the unburned or burned clearcut blocks.
The late Quaternary history of lodgepole and jack pines
Authors: Critchfield William B.
Published: January 2008

Lodgepole and jack pines (Pinuscontorta Dougl. ex. Loud. and Pinusbanksiana Lamb.), components of the North American boreal forest, have pioneering roles after major disturbances such as fire or glaciation. These species are closely related and hybridize in western Canada, but their fossil records and contemporary variation patterns suggest they had completely different late Quaternary histories. Several taxonomically recognized geographic races of lodgepole pine apparently survived the last glaciation without drastic modification, the northern races either persisting in far-northern refugia or migrating from the south. The uneven influence of jack pine on northern lodgepole populations implies repeated genetic contacts, but less marked introgression in the other direction could be of post-Pleistocene origin. Jack pine occupied its entire range after the last glacial maximum and lacks taxonomically recognized races. In the Great Lakes region, however, the presence of regionally distinct populations suggests the species had at least two Midwestern refugia. This hypothesis is contrary to the widely held view that jack pine occupied most or all of its range from a well-documented refugium in southeastern North America, but is supported by limited fossil evidence that pine persisted in the Midwest during the last glaciation.
Xylem sap analysis for determining the nutrient status and growth of Pinusponderosa
Authors: Stark N. , Spitzner C.
Published: January 2008

Natural variation in the ion concentration of the xylem sap of ponderosa pine (Pinusponderosa Laws.) in Montana was studied relative to tree height, crown aspect, age, time of day and year, species, tree to tree (within-stand variation), soil chemistry, and growth prediction. Xylem sap was extracted from branches at 2.4–2.7 MPa. The sap was analyzed chemically for 13 ions and total nitrogen. Extraction and analysis are fast and inexpensive. The top third of the crowns of P. ponderosa normally had higher ion concentrations in the sap for all but four ions. Crown aspect has little effect on the ion concentrations in sap. Age is a significant factor in xylem sap ion concentrations. Trees to be compared should be within 10 years in age. Time of day causes significant changes in ion concentration in the sap, but two stands can be compared over the same 2 to 8 sunlight hours. Xylem sap can be collected easily in the winter from frozen branches or in the summer when transpiration should be measured as well. Most ions decrease in concentration in the sap from the time of flush through hardening off. Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) sap has higher Ca than P. ponderosa sap. Slowly growing P. ponderosa had low Ca, Mn, K, P, and N, but high Mg and Si in the sap, compared with more rapidly growing trees. Xylem sap shows promise as a means of simultaneously evaluating the water, nutrient, and energy stress of trees and may be useful as a rapid means of predicting various parameters of tree growth.
Adenylate energy charge during stratification and germination of Quercusrubra
Authors: Hopper George M. , Parrish David J. , Smith David Wm.
Published: January 2008

In an effort to better understand dormancy in Quercusrubra, adenylate energy charge was measured during stratification and germination. Adenylate energy charge has been suggested as a useful index of metabolic activity and seed vigor. Adenylate nucleotides were measured using the luciferin–luciferase assay. Energy charge was compared with germinability at 28 days. Energy charge increased during the first 2 weeks of stratification when germination was low. Thereafter, energy charge decreased before increasing at 8 weeks of stratification. This second rise in energy charge coincided with increased germinability. During the 28-day germination period, energy charge fluctuations appeared to be associated with peaks of activity in the growth of roots and shoots. Application of energy charge as a biochemical index of the degree of dormancy and seed quality is discussed.
Mineral nutrition, dinitrogen fixation, and growth of Alnuscrispa and Alnusglutinosa
Authors: Prégent G. , Camiré C.
Published: January 2008

Invitro cultures of Alnuscrispa (Ait.) Pursh and Alnusglutinosa (L.) Gaertn. were used to estimate critical foliage levels of selected nutrients for optimal growth and dinitrogen (N2) fixation. For A. crispa to obtain 90% of maximum growth and N2 fixation, foliar levels of 0.12% P, 0.13% Mg, <0.31% K, and <0.04% Ca on a dry weight basis were needed. For A. glutinosa, the critical levels were 0.138% P, 0.10% Mg, 0.29% Ca, and ~0.20% K. From all the deficiencies observed, P had the more pronounced effects on N status of both species.
Evaluating growth responses to fertilization
Authors: Auchmoody L. R.
Published: January 2008

When fertilizers increase radial growth rates, they also increase the diameter of trees that will be used to compute future basal area responses. If the mean basal area growth per tree is computed for fertilized trees that are larger than the unfertilized trees, the length of time that fertilizers directly affect growth can be overestimated. In this paper, a model that describes mean basal area responses per tree over time as a function of direct nutrient effects and indirect tree-size effects is suggested. Application of the model to a uniform field fertilization experiment shows that after the 1st year, some or all of the average basal area response of individual trees is due to the difference in size between fertilized and unfertilized trees. To evaluate direct fertilizer responses properly, mean basal area growth per tree must be adjusted for the unequal size of fertilized and unfertilized trees.
A comparison of vegetative cover and tree community structure in three forested Adirondack watersheds
Authors: Cronan Christopher S. , DesMeules Marc R.
Published: January 2008

The Integrated Lake–Watershed Acidification Study (ILWAS) was conducted using three forested watersheds (Panther, Sagamore, and Woods) in the central Adirondack Park of New York State. By comparing the biogeochemical behavior of these watersheds, the ILWAS investigators hoped to elucidate the major ecosystem parameters controlling the fate of strong acids introduced from the atmosphere to lake–watershed systems. The ILWAS vegetation research program was designed to compare the quantitative patterns of forest structure in these midelevation watersheds. Results showed that the ILWAS catchments contain closely related variants of the northern hardwood – spruce – fir complex of the Adirondack region. The dominant tree species in these watersheds are beech (Fagusgrandifolia Ehrh.), red spruce (Picearubens Sarg.), sugar maple (Acersaccharum Marsh.), red maple (Acerrubrum L.), and yellow birch (Betulaalleghaniensis Britt.). On an areal basis, the watersheds contain 57–88% hardwood cover type and 5–29% spruce–fir cover type. Mean live basal area values range from 22 to 30 m2 ha−1 between catchments, while standing dead basal area values range from 4 to 8 m2 ha−1. Mean live stem densities range from 1400 to 1700 stems ha−1. Mean aboveground biomass projections for the tree stratum in the three watersheds range from 143 to 199 Mt ha−1, while estimated aboveground annual biomass increments range from 4.1 to 5.3% of standing biomass.
Decomposition of logging residues in Douglas-fir, western hemlock, Pacific silver fir, and ponderosa pine ecosystems
Authors: Erickson Heather E. , Edmonds R. L. , Peterson C. E.
Published: January 2008

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.
Relationship between jack pine growth and site variables in New Brunswick plantations
Authors: Hamilton W. N. , Krause H. H.
Published: January 2008

Mean and dominant tree heights were determined on 28 sample plots within 18 jack pine (Pinusbanksiana Lamb.) plantations varying in age from 6 to 16 years. An average dominant tree was removed from each plot for stem analysis. The height versus age data were used to determine 2-, 3- and 4-year growth intercepts in each sample tree. Growth intercepts were positively correlated with foliar concentrations of nitrogen, phosphorus, and potassium, total nitrogen concentration in the main rooting layer of the mineral soil, as well as soil physical parameters associated with good drainage. Depth of forest floor and Ae horizon, clay content, bulk density, and drainage class were negatively correlated with growth. Close correlations were also revealed for site occupancy by ericaceous ground cover species and growth intercepts. The numerous site variables included in this study were reduced to five factors with significance to jack pine growth: (i) ericaceous cover – forest floor, (ii) drainage, (iii) extractable P, (iv) exchangeable K, and (v) Ae horizon development.
The effects on the short-run supply of wood from subsidized regeneration measures: an econometric analysis
Authors: Brännlund Runar , Göransson Monica , Löfgren Karl Gustaf
Published: January 2008

Using an econometric model of the sawtimber and pulpwood market in price region 1 (the northern part of Sweden), it is considered whether the subsidies paid to regeneration costs in this region since the end of the 1960's have had any measurable short-run effect on wood supply. Two interrelated markets are introduced, a sawtimber market and a pulpwood market. The sawtimber market is modelled as a competitive market, while the pulpwood market is treated as a monopsonistic market structure. The model shows a good fit and the subsidies seem to have had a significant negative effect on sawtimber supply and an insignificant negative effect on pulpwood supply. The paper ends with a discussion of possible reasons for this somewhat unexpected result.
Effects of disrupting stem sapwood water conduction on the water status in Douglas-fir crowns
Authors: Brix H. , Mitchell A. K.
Published: January 2008

The sapwood cross-sectional area at breast height was reduced by 0 (control), 42, 69, and 100%, in 36-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees to study treatment effects on the water status in the crowns. Only the complete removal of breast-height sapwood affected the leaf water potential which decreased rapidly the 1st day, but then changed little for the next 38 days varying only from −2.3 to −2.6 MPa. Water use for those trees was limited to that stored above breast height, primarily in stem sapwood, and amounted to approximately 45 L. This corresponded to 6.5 mm of precipitation or 4% of potential transpiration. The finding that leaf water potential was not affected by partial sapwood reduction but rather by changes in soil water potential suggests that resistance to water flow in stems was small compared with that in other parts of the water-flow pathways of soil and trees.
Tree vigor and stand growth of Douglas-fir as influenced by laminated root rot
Authors: Oren Ram , Thies Walter G. , Waring Richard H.
Published: January 2008

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.
Screenometer: a device for sampling vegetative screening in forested areas
Authors: Rudis Victor A.
Published: January 2008

A device for estimating the degree to which vegetation and other obstructions screen forested areas has been adapted to an extensive sampling design for forest surveys. Procedures are recommended to assure that uniform measurements can be made. Examination of sources of sampling variation (observers, points within sampled locations, series of observations within points, and sectors within series) and sampling intensity suggests a sample design which involves a combination of points and sectors.
Relationship between phloem thickness and lodgepole pine growth characteristics
Authors: Shrimpton D. M. , Thomson A. J.
Published: January 2008

Depth of the phloem (inner bark) layers in lodgepole pine (Pinusconforta Dougl. var. latifolia Engelm.) is a factor in the development of outbreaks of the mountain pine beetle (Dendroctonusponderosae Hopk.). Five lodgepole pine stands in the interior of British Columbia spanning the ages affected by this beetle (47–147 years) were studied. Relationships were determined between thickness of the phloem layer and radial and area increments over various periods of time, as well as DBH. The thickness of the phloem layer declined over the age spanned in this study. The best predictor of phloem thickness was the basal area increment in the 6–10 years before sampling. Diameter was a poor predictor of phloem thickness.
Use of mycelial slurries of mycorrhizal fungi as inoculum for commercial tree seedling nurseries
Authors: Boyle C. D. , Robertson W. J. , Salonius P. O.
Published: January 2008

Blended mycelial slurries of a variety of ectomycorrhizal fungi were assessed for their suitability as inoculum for containerized tree seedlings. Mycelium of most fungi tested, with the exceptions of Pisolithustinctorius (Pers.) Coker & Couch and Paxillusinvolutus (Batsch.: Fr.) Fr., withstood blending well. Viability remained high after storage in modified Melin–Norkrans agar medium, water, or dilute saline at either 4 °C or room temperature, indicating that slurries are robust enough to tolerate conditions that would be encountered in a commercial setting. Experiments investigating methods for applying slurries to containerized seedlings were conducted using Hebelomalongicaudum (Pers.: Fr.) Kummer. Slurry infectivity dropped after it was mixed into a peat–vermiculite growing medium, particularly in the presence of high levels of fertilizer. This indicated that incoculum should not be added to multipots until short roots capable of becoming mycorrhizal are present and that contact of the inoculum with fertilizer should be avoided. Injection of slurry into the root zone resulted in the most consistently high colonization, but application of the slurry to the surface of the growing medium was also effective, the latter being more feasible in a commercial setting. Mycorrhizae developed with as little as 1 mg mycelium per seedling, although 100 mg gave more consistent results. In inoculation trials in which slurries of nine representative fungi were injected into the root zones of 8-week-old black spruce or jack pine seedlings, five of the fungi consistently formed mycorrhizae. For these fungi, slurries could be an effective inoculum.
Genetic diversity and population structure of Piceaglauca on an altitudinal gradient in interior Alaska
Authors: Alden John , Loopstra Carol
Published: January 2008

Allozyme variation at 13 loci for 11 enzyme systems was studied in four white spruce (Piceaglauca (Moench) Voss) populations extending from a floodplain at 120 m above sea level to the altitudinal tree limit at 750 m above sea level in interior Alaska. Although 97% of the total genetic diversity was among trees within stands and 1% was among stands within populations, frequencies of several allozymes and allozyme genotypes were significantly different (P < 0.05) among populations. Ninety-two percent of the loci were polymorphic. Total heterozygosity was 0.276. Heterozygosity and allozyme frequencies were not related to altitude. The population at the tree limit was as genetically diverse as populations at low elevations [Formula: see text] and contained four of seven rare alleles observed in all populations. These observations suggested that white spruce is genetically diverse in interior Alaska and the tree-limit population will continue to colonize new habitats. Genetic distance was not related to altitude and geographic distance and was less between the tree-limit and upper slope populations than among other populations A detectable gene substitution rate was estimated at 10−6 per year. Populations on the upper slope and at the tree limit may have diverged about 2500 years ago and reached tree-limit altitudes only recently. Populations at low altitudes may have diverged during early Holocene white spruce expansion. We concluded that white spruce is genetically diverse in a small geographic area in interior Alaska. Results suggested that local white spruce populations should be regenerated from indigenous seed and that provenance research is needed to support afforestation programs.
The influence of moisture and mineral soil on the combustion limits of smoldering forest duff
Authors: Frandsen William H.
Published: January 2008

Laboratory experiments were conducted to investigate how both mineral soil and moisture content affect the smoldering combustion in forest duff. Peat was used to represent the fermentation and humus horizons (Oe and Oa soil horizons) of a coniferous forest floor nominally called duff. Although moisture content is traditionally considered to be a major factor limiting the combustion of duff, inorganic content from mineral soil also limits combustion. Results show that the peat moss selected sustained smoldering up to the range 93 to 103% moisture content in its natural state of 3.7% inorganic content (both relative to the dry organic mass). Adding inorganic material in the form of finely divided mineral soil (clay to silty clay) depressed the moisture limit that previously permitted smoldering. Smoldering is not sustained when the inorganic to organic ratio reaches 4.3 (430%) in the absence of moisture. Between these two extremes, there is an approximate linear decrease in the moisture limit with increasing inorganic content. A comparison with the limits of smoldering for duff (fermentation) samples collected from under an inland Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) canopy shows a similar dependence on moisture and inorganic content.
Hydraulic design of culverts on forest roads
Authors: Donahue John P. , Howard Andrew F.
Published: January 2008

Design of drainage structures is an important part of planning forest roads, which usually includes culverts. Determining the appropriate pipe size for a given site involves estimation of expected flows and evaluation of the hydraulic performance of pipes of different sizes. In this paper a review of the hydraulic relationships applicable to the evaluation of pipe hydraulics is presented. A computer model is introduced that incorporates these relationships. The model is used to compare two algorithms for computing headwater depths, given inlet control (supercritical flow). The relative efficiency of four inlet types was also investigated. Results indicate that potential cost savings exist by altering inlet geometry and that computer-assisted design can facilitate accommodation of conflicting design goals.
Effects of broadcast slash burning on fuels and soil chemical properties in the Sub-boreal Spruce Zone of central British Columbia
Authors: Macadam A. M.
Published: January 2008

Soil samples were taken before and 9 and 21 months after the operational broadcast burning of logging slash in two clear-cuts in the Sub-boreal Spruce Zone of central British Columbia. Average slash consumption on the two clear-cuts was estimated from line intersect samples at 20 and 24 t/ha and forest floor depth was reduced by 28 and 36%. Nine months after burning, soil N had decreased by 376 kg/ha (18% of preburn levels) while available P had increased by 37–157 kg/ha. Burning resulted in substantial increases in forest floor base saturation, pH, exchangeable Ca and Mg, and available P. Changes within the 0–15 and 15–30 cm mineral soil layers were variable and in general less pronounced. Significant positive correlations were observed between the consumption of large fuels and postburn changes in forest floor pH and exchangeable Ca and Mg. Changes in forest floor N were negatively correlated with amounts of fine slash consumed. A strongly negative correlation was observed between forest floor depth of burn and changes in forest floor exchangeable K concentrations.
Patterns of log decay in old-growth Douglas-fir forests
Authors: Sollins Phillip , Cline Steven P. , Verhoeven Thomas , Sachs Donald , Spycher Gody
Published: January 2008

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).
A comparative analysis of the reduced major axis technique of fitting lines to bivariate data
Authors: Leduc Daniel J.
Published: January 2008

not available
Growth responses of field-grown loblolly pine to chronic doses of ozone during multiple growing seasons
Authors: Shafer S. R. , Heagle A. S.
Published: January 2008

Dose–response relationships were developed for ozone and four full-sib families of Pinustaeda L. Seedlings were planted in field plots in open-top chambers near Raleigh, North Carolina, and exposed daily during three growing seasons (1985, 1986, and 1987) to ozone at concentrations from 0.022 to 0.092 μL/L of air (seasonal mean concentrations for the daily exposure period 08:00 to 20:00 eastern standard time). Plants were harvested on five dates during the study to quantify effects of ozone on growth. Ozone suppressed stem height, root collar diameter, total branch length, and (or) dry weights of above-ground parts of plants in three families, but response to ozone depended upon dose, family, and the plant part measured. One family exposed during 1985 and 1986 did not exhibit significant growth responses to ozone. The family that exhibited the greatest growth suppression in 1985 and 1986 was exposed during the 3rd year, and ozone continued to reduce growth. Suppression of root dry weight was observed after three seasons of exposure. Root collar diameter and dry weight of stem + branches (without needles) may be the most useful measurements of growth response in multiple-year experiments. Dose–response models predicted that ambient levels of ozone could reduce growth relative to the growth predicted for chronic exposure to half-ambient levels (charcoal-filtered air). For aboveground woody tissue, this suppression ranged from 0 to 19% among the four families after two seasons of exposure and was 13% for the most sensitive family after three seasons.
Geographic variation, nursery effects, and early selection in lodgepole pine
Authors: Ying C. C. , Thompson C. , Herring L.
Published: January 2008

Thirty provenances of lodgepole pine (Pinuscontorta Dougl.) test stock raised at two nurseries, Cowichan Lake (coastal British Columbia) and Red Rock (interior British Columbia), were assessed in two 15-year field trials. Analyses indicated three broad geographic regions of genetic differentiation in British Columbia: coast, coast–interior transition, and central and southern interior. Provenance elevation was found to have a strong influence on growth. The results suggest that the present seed transfer guidelines for lodgepole pine in the interior region of this province are conservative enough to prevent the use of maladapted seed sources. Nursery effect declined over a period of 15 years, while provenance differences increased with the age of the trials. Interactions between provenances and sites also increased after age 9. This suggests that the effect due to seedling culture and environment in the nursery is short-term relative to the influence of the genetic component. Nursery growth was generally not a good predictor of provenance field performance.
Some observations on the leaf oil terpene composition of mountain hemlock, Tsugamertensiana
Authors: Rudloff E. Von , Lapp Martin S.
Published: January 2008

The leaf oil terpene composition of mountain hemlock (sugamertensiana (Bong) Carr.) from eight central–coastal, three interior, and three southern populations was determined. High intra- but low inter-population variation was found. No significant elevational differences were recorded. Most trees from the southern populations had lower car-3-ene and higher α-pinene and β-phellandrene percentages than those from northern locations. Interior populations did not differ extensively from coastal populations. Owing to the high tree-to-tree variability, putative hybridization of mountain hemlock with western hemlock would be difficult to detect by leaf oil terpene analysis.
Trends in genetic and environmental parameters, genetic correlations, and response to indirect selection for 10-year volume in a Norway spruce clonal experiment
Authors: Bentzer B. G. , Foster G. S. , Hellberg A. R. , Podzorski A. C.
Published: January 2008

Seventy-five clones of Norway spruce (Piceaabies (L.) Karst.) were tested for height, diameter, and volume at two locations in southern Sweden. Total height was measured at seven ages from age 1 to 10 years, whereas diameter at breast height was measured and volume index calculated only at age 10. Clone effects were consistently significant for all traits, whereas clone × location interaction effects only showed significance for diameter at breast height at age 10, volume index, and height at age 3. Location effects for height were small and error effects large, up to age 6. Between ages 7 and 10, location effects increased considerably, while error effects decreased correspondingly. Clone-mean heritability for height remained stable from years 3 to 10, but was slightly higher at age 1. Genetic correlations between traits were generally large, which made efficient selection for height possible as early as age 4. The correlated response in volume index at age 10, when selecting for height at age 4 or later, was exceptionally good, and it provided gain estimates in volume that were as large as or larger than estimates from direct selection for volume index at age 10.
Genetic improvement of sugar maple for high sap sugar content. I. Clone selection and seed orchard development
Authors: Kriebel Howard B.
Published: January 2008

A grafted seed orchard of Acersaccharum Marsh, was established in Ohio in 1957 as part of a program of genetic improvement of sugar yield. During the 3rd decade, the orchard trees averaged 4.2% sap sugar. Although environmental sources of variance in sugar concentration were large, clonal differences were evident and generally consistent over the years; the clone × year interaction was negligible. Sap sugar concentration varied from year to year, but after an increase coinciding with early crown development in the 1st decade, there was no upward or downward trend with age. Inclusion of one seedling family in the orchard made it possible to obtain an approximation of within-family variance by comparison with within-clone variance. It was estimated to be about one-third of total family variance. The clone–family comparison also suggested that about 11% of total clonal variance was a rootstock effect. Sap tests over 3 years in a plantation of seed-orchard offspring showed that an initial thinning to an average 6.3 × 6.3 m spacing would leave trees with an average 4% sap sugar concentration. At final spacing the concentration would be higher. Only a few clones in the orchard produced medium or heavy crops of male or female flowers prior to age 27, but those from which seed was collected in early years averaged at least 4% sap sugar. All clones and the seedling family flowered by age 27.
Estimating leaf area of Abieslasiocarpa across ranges of stand density and site quality
Authors: Long James N. , Smith Frederick W.
Published: January 2008

For a given species, differences in the relation between leaf area and sapwood cross-sectional area at breast height have been attributed to the effects of varying stand density and site quality. When leaf area of Abieslasiocarpa (Hook.) Nutt. is estimated as a function of sapwood cross-sectional area at breast height and distance from breast height to the midpoint of the crown, the apparent effects of stand density and site quality are eliminated. A comparison of these results with those for Pinuscontorta Dougl. suggests this model form should provide unbiased estimates of leaf area for a variety of species and stand conditions.
A proposal for the development of a land race of Sitka spruce in Newfoundland
Authors: Hall J. Peter
Published: January 2008

Results from a 20-year-old series of exotic Sitka spruce provenance trials in western Newfoundland were analysed. The average performance of the Sitka spruce over nine locations was poor, but some trees grew faster than the native black spruce on three of the sites. A land race may be in the early stages of development. Exploitation of this variation through a selection and breeding program presents an opportunity to increase forest productivity in western Newfoundland.
Conifer bole utilization by wood-boring beetles in western Oregon
Authors: Zhong H. , Schowalter T. D.
Published: January 2008

We studied wood excavation by scolytid and cerambycid beetles in decomposing boles of four conifer species during the first two years on the ground in western Oregon. Colonization density and gallery volumes were measured in experimental boles (0.5 m diameter × 5 m length) of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), Pacific silver fir (Abiesamabilis (Dougl.) Forbes), and western red cedar (Thujaplicata Donn). Ambrosia beetles (Coleoptera: Scolytidae) colonized boles only during the 1st year and were essentially restricted to Douglas-fir and western hemlock (removing 0.2% of the sapwood volume). Bark beetles (Coleoptera: Scolytidae) colonized boles only in the 1st year, primarily in Douglas-fir and Pacific silver fir (removing 7–8% of the phloem surface area). Wood borers (Coleoptera: Cerambycidae) excavated an additional 2.3% of the phloem surface area of Pacific silver fir in the 1st year and continued to excavate all species except Douglas-fir during the 2nd year. Consequences for the decomposition process are discussed.
Assessing multiple estimates of plantation productivity
Authors: Reed David D. , Jones Elizabeth A.
Published: January 2008

Forest managers are often faced with several estimates of plantation productivity. Not only are there different measures of productivity, such as site index or mean annual increment at some fixed age, but estimates of each may be obtained from several sources, including habitat classification systems, soil site equations, and growth measures from young stands. Site index cannot be truly observed until the stand reaches index age, and mean annual increment cannot be truly observed without measuring standing volume at the age of interest. Without observations of these "true" values, common measures of accuracy have only generally evaluated performance compared to a standard method that accurately predicts these values. In this paper, a technique of assessing alternative estimates of site index and mean annual increment in the absence of observations of the true values is presented and is illustrated through a quantitative evaluation of the alternative productivity estimates for young red pine plantations.
Microwave digestion of tree foliage for multi-element analysis
Authors: Kalra Y. P. , Maynard D. G. , Radford F. G.
Published: January 2008

A microwave digestion procedure was developed for multi-element determinations in tree foliage by inductively coupled plasma–atomic emission spectrometry. The procedure involved the sequential digestion of 0.500 g of plant material with HNO3 (10 mL), H2O2 (1 mL), and HCl (2 mL) at 90% power for 30 min, 90% power for 15 min, and 30% power for 10 min, respectively. The proposed method gave Ca, Mg, K, Na, Mn, P, and S results in good agreement with the National Institute of Standards and Technology plant reference materials. Iron and aluminum concentrations were 20 to 30% lower than the certified National Institute of Standards and Technology values. Recovery of standard additions of the elements tested (including iron and aluminum) ranged from 93 to 105%. The proposed digestion method provides accurate and precise results for multi-element analysis on one solution. In addition, HClO4, an extreme laboratory hazard, has been replaced in the digestion procedure by H2O2. The microwave digestion method has been used successfully in our laboratory for over 1 year for routine analysis and for a quality assurance program using a variety of plant materials. With this method 36 to 48 samples per person per day can be prepared for inductively coupled plasma–atomic emission spectrometry analysis.
Les caractéristiques papetières du bois attaqué par la tordeuse des bourgeons de l'épinette
Authors: Nlombi K. , Koran Z.
Published: January 2008

Chemithermomechanical pulp was manufactured from a supply of budworm-killed balsam fir wood in a pilot plant at the Université du Québec. The physical properties of these pulps were evaluated according to the standard methods of the Canadian Pulp and Paper Association and compared with those of a corresponding sample of experimental pulp prepared from a supply of sound balsam fir wood under the same experimental conditions. It was found that the trees killed 3 years before they were cut produced significant reductions in tear strength (50%), breaking length (25%), burst (24%), and in its brightness (4.5%). The decreases were accompanied by a corresponding increase in the opacity of the sheet (5%) and a significant decrease in energy consumption (15%), the latter representing an important reduction in the electric energy cost of refining. Since in practice budworm-killed wood is always used in some blends with sound wood, the reductions in tear and tensile properties will be directly proportional to the proportions of each type of wood. Thus, in a 50/50 blend of chips made up of sound wood and budworm-killed wood, the burst strength is reduced only by 12%, but at the same time the decrease in the electric bill is also cut in half. Thus, if the budworm-killed forest is harvested not later than 3 years after the trees have been killed, the utilization of this wood in the pulp and paper industry is more promising than we were led to believe in the past.
A mathematical model for fire containment
Authors: Anderson David H.
Published: January 2008

The problem of containment of wildland fires is considered. One method of attack is to attempt to put out the flames directly. This involves the suppression team working at the fire front during the entire containment process. This method is not possible if the fire is spreading too rapidly. The analysis presented in this paper outlines conditions under which containment using such a direct method is possible. A less restrictive alternative is to use some method of indirect attack. A method is presented that would be simple to apply in practice, and even if the method itself is not used, it would assist fire managers in preliminary fire control planning and initial attack dispatching. Estimates are required for various parameters controlling the spread of the free-burning fire, and these can either be obtained directly from the user or from a fire-modelling computer program such as the USDA Forest Service BEHAVE program.