bluuebunny/crossref_metadata_2025 huggingface dataset:
Substrate freeze–thaw in a drained Alberta fen
Authors: Swanson L. E. , Rothwell R. L.
Published: January 2008

The study of ground frost levels in a drained and undrained forested fen showed a significant delay in thaw as well as lower temperatures at 40 and 60 cm depths in the drained area because of the insulating effect of drier surface peat in the drained area. The undrained area froze to greater depths than the drained area, but thawed more rapidly. Ice was present year-round at 16.7% of the sample points in the portion of the drained area of low hydraulic conductivity. Thickness of the frozen layer appeared to be related to hydraulic conductivity as well as drainage. Thawing from underneath the frozen layer accounted for 38% of total thaw in the undrained area.
Effects of incomplete block design and stand structure on heritability of growth in a jack pine family test in Manitoba
Authors: Klein J. I.
Published: January 2008

Height and diameter were measured in three plantations of a Pinusbanksiana Lamb, family test with stand structure in southeastern Manitoba at 10 years from planting. The plantations were established in a cubic lattice design. For height and diameter, respectively, 90.6 and 90.8% of total variance among trees was within plots, 1.7 and 2.0% was due to stands, 2.0 and 2.0% to families, 2.6 and 1.8% to family by plantation interaction, and the remaining 3.1 and 3.5% to residual plot error. All tested effects were significant for height and diameter at P < 0.05. Family, within-family, and individual tree heritabilities were 0.49 and 0.52, 0.065 and 0.065, and 0.096 and 0.098 for height and diameter, respectively. The stands component was excluded from within-family contributions in estimating heritability. When the data were analyzed as a randomized block experiment, the variance components for plot error increased to 13.9 and 11.3% of total variance, whereas the interaction component decreased to less than 1%. Heritability estimates were slightly lower than those from cubic lattice analysis. Cubic lattice design and analysis were effective in reducing plot error.
Promotion of flowering in western hemlock by gibberellin A4/7 applied at different stages of bud and shoot development
Authors: Owens John N. , Colangeli Anna M.
Published: January 2008

Cone buds were induced on container-grown and field-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) clones during a 3-year period to study the effects of time and duration of gibberellin A4/7 treatment on cone induction, sexuality of cones, and to relate these results to bud and shoot development. The most effective treatment times preceded anatomical differentiation. The most abundant pollen cones and seed cones were produced when trees were sprayed with gibberellin A4/7 before vegetative bud burst and early shoot elongation. Two to three weekly gibberellin A4/7 applications starting at preswollen and swollen-bud stages were adequate for pollen-cone production. Pollen-cone production decreased when the applications were started at vegetative bud burst or during early shoot elongation. A minimum of three weekly applications were required for seed-cone production, and applications were equally effective when started at preswollen, swollen, and vegetative bud burst stages. Seed-cone production decreased when three weekly applications were started during early shoot elongation; however, this was overcome by increasing the number of applications.
Estimation of stand means and other ratios in point sampling
Authors: Vries P. G. De , Schreuder H. T.
Published: January 2008

There exist best linear unbiased estimators based on point sampling data, if certain linearity conditions hold, for any ratio in a tree population (e.g., mean basal area or Lorey's mean stand height). Variance expressions for these estimators are given, and approximate variance expressions for the estimated ratios are proposed.
A soil-site study for inland Douglas-fir
Authors: Monserud Robert A. , Moody Ula , Breuer David W.
Published: January 2008

A soil-site study was conducted for inland Douglas-fir growing in northern Idaho and north western Montana. The hypothesis was that standard soil survey procedures would provide edaphic data that could predict site index in the absence of site trees. Soil profile descriptions and physical analyses were obtained on 133 plots, along with several physiographic site descriptors. Chemical analyses were performed on soil samples from a third of these plots, and moisture availability was determined on 60% of the plots. Site index was based on felled-tree stem analyses. Elevation was the strongest predictor, accounting for a third of the variation in site index. The addition of habitat type information resulted in a significant improvement (as did longitude and precipitation), but still left over half the variation unexplained. After examining numerous soil properties the standard error could only be reduced 0.3 m, a disappointing result in light of the considerable time and expense necessary for soil sampling. The causes of these low soil–site correlations could not be conclusively determined, but the most likely explanations are (i) that the number of important site factor interactions occurring in this large and complex study area far exceeded the sample size, and (ii) failure to measure the true causes of site productivity.
Growth and ectomycorrhiza formation of Douglas-fir seedlings grown in soils collected at different distances from pioneering hardwoods in southwest Oregon clear-cuts
Authors: Borchers Susan L. , Perry David A.
Published: January 2008

A greenhouse bioassay was used to compare the growth, ectomycorrhiza formation, and foliar nutrient concentrations of Douglas-fir seedlings grown in soils collected at different distances from hardwood species. Soil nutrient concentrations and bulk densities were also determined. The soils were collected from two southwestern Oregon sites that had been clear-cut and broadcast burned 5 years previously. The sites, poorly stocked with conifer reproduction, were occupied primarily by grasses, forbs, and scattered individuals of tanoak (Lithocarpusdensiflora (Hook. & Arn.) Rehd.), Pacific madrone (Arbutusmenziesii Pursh), and canyon line oak (Quercuschrysolepis Liebm.). Five-month-old seedlings grown in media containing mineral soil collected beneath hardwood crowns had on average 60% greater height, 2.2 times greater weight (roots plus shoots), and almost 2 times more total and ectomycorrhizal short roots than seedlings grown in media containing soil collected more than 4 m from a hardwood. Rhizopogon sp. and Cenococcumgeophilum dominated on seedlings grown in hardwood soils, and an unidentified brown ectomycorrhiza dominated on seedlings grown in open area soils. The effect of hardwoods did not vary among the three hardwood species or between the two sites. A study of soils collected at various distances from hardwoods indicated that the effect extended between 2 and 3 m. Average foliar nitrogen was higher for seedlings grown in hardwood area than in open area soils, but differences were not statistically significant. Differences in other foliar nutrients of seedlings grown on soils from beneath the three hardwood species were inconsistent. Differences in soil nutrient concentrations were also inconsistent; however, rates of mineralizable nitrogen (anaerobic) were from 2 to nearly 6 times higher in hardwood area than open area soils, and soil pH was higher. Results suggest that the pioneering hardwoods strongly influence soil biological activity in these clear-cuts and impose one or more soil patterns that favor establishment and growth of conifer seedlings.
Paclobutrazol and triadimefon effects on conifer seedling growth and water relations
Authors: Driessche R. van den
Published: January 2008

Growth responses of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings to the gibberellin synthesis inhibitor paclobutrazol were examined in sand culture. Shoot and root dry weights and root lengths were reduced at 5 mg (active ingredient) of paclobutrazol per litre, in the nutrient solution, although the proportion of dry matter allocated to roots was increased by 5 mg (active ingredient) of paclobutrazol per litre. Similar effects were observed with triadimefon, although the reduction in height growth was less in triadimefon-treated seedlings than in paclobutrazol-treated seedlings. Stomatal conductance, transpiration, and needle area:weight ratio were reduced by both paclobutrazol and triadimefon treatments of 13.5-week-old seedlings, although paclobutrazol was more effective than triadimefon in reducing needle arear:weight ratio. Treatment of 1-year-old container seedlings of Douglas-fir and white spruce (Piceaglauca (Moench) Voss) by shoot dipping or plug drenching with paclobutrazol, in December or March, reduced height growth and new needle area:weight ratio after 6 weeks growth in a greenhouse. Xylem water potential of paclobutrazol-drenched seedlings was increased by 0.7 MPa above controls (−1.8 MPa) 11 weeks after planting, and stomatal conductance of drenched white spruce increased with paclobutrazol concentration.
Time series modelling of relationships between climate and long-term radial growth of loblolly pine
Authors: Jordan D. N. , Lockaby B. G.
Published: January 2008

Time series techniques were utilized to evaluate the influence of selected climatic factors on basal area increment growth of loblolly pine (Pinustaeda L.) in rural Alabama and to address the possibility of a changing growth trend. This study is unique in its application of these techniques to an important southern United States timber species. An important asset of the study is the availability of long-term weather records from a weather station only 0.5 km distant. Basal area increment from 1906 to 1986 was modelled using an autoregressive integrated moving average model. Significant predictors of annual increment are previous annual increment, average temperature in June, precipitation in May, June, and August, the annual drought index for southern pine, and the Palmer drought severity index value for August. The best predictor variable examined was the August Palmer drought severity index value. Basal area increment was examined for interventions indicating a changing growth trend. No significant (p ≤ 0.05) interventions were observed in the climatically modelled series.
Stand dynamics and red spruce decline
Authors: Deusen Paul C. Van
Published: January 2008

The red spruce (Picearubens Sarg.) growth decline in the northeastern United States does not appear to be ubiquitous. Some selected tree-ring data sets are compared graphically and with two models that tend to support the notion that differences exist between stands as to the presence and degree of decline. It appears that the degree of post-1960 decline is related to the proportion of trees showing a pre-1950 growth increase, and stratifying the data into as few as two classes can improve model fit substantially. The models used in the comparisons are of interest in themselves, because they are capable of exhibiting the mathematical phenomenon of chaos.
Influence du drainage et de la texture du dépôt sur la vulnérabilité du Sapin baumier et de l'Épinette blanche aux attaques de la Tordeuse des bourgeons de l'épinette
Authors: Archambault Louis , Gagnon Robert R. , Pelletier Georges , Chabot Michel , Bélanger Louis
Published: January 2008

Balsam fir (Abiesbalsamea (L.) Mill.) and white spruce (Piceaglauca (Moench) Voss) mortality was measured in five areas of the province of Quebec severely affected by spruce budworm (Choristoneurafumiferana (Clem.)) defoliation. Mortality was compared for different combinations of soil texture and drainage. For balsam fir, two vulnerability classes, based on combinations of soil texture and drainage, were defined. In the first class, mortality reached 74% of the preoutbreak volume, as compared with 86% in the second class. For white spruce, three vulnerability classes were defined based on soil texture and drainage combinations. In the low, moderate, and high vulnerability classes, white spruce mortality reached 10, 26, and 52%, respectively. Soil moisture regime is an important factor in determining vulnerability. From these results, we propose an ecosystem classification based on vulnerability to spruce budworm. Particular reference is made to what significance the findings may have for forest integrated pest management.
Growth and foliar nutrient response to fertilization and precommercial thinning in a coastal western red cedar stand
Authors: Harrington Constance A. , Wierman Charles A.
Published: January 2008

Seven silvicultural treatments were applied to a young (15- to 20-year-old), naturally regenerated western red cedar (Thujaplicata Donn ex D. Don) stand growing on a poor-quality site in western Washington. The treatments were as follows: unthinned, unfertilized (untreated); unthinned, fertilized with ammonium nitrate, dicalcium phosphate, and potassium sulfate; thinned, unfertilized; thinned, fertilized with urea; thinned, fertilized with ammonium nitrate; thinned, fertilized with ammonium nitrate and dicalcium phosphate; and thinned, fertilized with ammonium nitrate, dicalcium phosphate, and potassium sulfate. Elemental application rates were 300 kg nitrogen, 100 kg phosphorus, 129 kg calcium, 100 kg potassium, and 41 kg sulfur per hectare. Growth and foliar nutrient concentrations were monitored for 5 years. Five-year height growth and diameter growth of the 20 tallest trees per 0.08-ha measurement plot were both substantially greater in all thinned or fertilized treatments than in the unthinned, unfertilized treatment. The three best treatments for height growth (the treatments containing ammonium nitrate and dicalcium phosphate) had 65% more growth than the unthinned, unfertilized treatment. The two best treatments for diameter growth (thinned, fertilized with ammonium nitrate and dicalcium phosphate) had 106% more growth than the unthinned, unfertilized treatment. The effects of thinning alone were small compared with the effects of fertilization alone or fertilization combined with thinning. Initial foliar nitrogen concentrations showed that the site was nitrogen deficient, and both nitrogen sources, urea and ammonium nitrate, increased growth. The addition of dicalcium phosphate resulted in significantly greater incremental growth above that attributed to nitrogen alone, but the further addition of potassium sulfate did not increase growth significantly. Increases in foliar nitrogen and phosphorus associated with fertilization were still evident 5 years after treatment. All sizes of trees responded to treatment, and growth of the total stand followed the same trends as for the 20 tallest trees per plot. Basal area growth on an absolute basis was best in the unthinned, fertilized treatment (more than twice that of the unthinned, unfertilized treatment) and on a percent basis was best in the thinned treatment fertilized with ammonium nitrate, dicalcium phosphate, and potassium sulfate.
Modelling disaggregated lumber demand and supply by constrained estimation techniques
Authors: McKillop William , Liu Gao
Published: January 2008

Constrained estimation techniques were used to estimate a 12-equation demand and supply system for Douglas-fir and hemlock–fir (true fir) lumber by clear and common grades. Such techniques combine sample information with nonsample information and produce estimates with smaller variances than those based only on sample data. Conventional econometric estimation was compared with a quadratic programming technique with regression coefficients constrained to their a priori correct signs. A goal programming technique that minimized the sum of the absolute deviations was rejected because of its substantially different results and lack of information on the statistical properties of its estimates. The quadratic programming technique had the advantages of statistical efficiency, objectivity, and speed. The conventional estimation technique excluded fewer variables from the system and thus was less susceptible to omission of variables bias. Elasticity estimates for most key variables were similar. Quadratic programming versus conventional estimates of demand elasticity were, respectively, −0.95 and −0.88 for Douglas-fir clears, −2.83 and −2.91 for Douglas-fir commons, and −2.13 and −2.27 for all Douglas-fir; whereas supply elasticities for hemlock–fir commons were 1.35 and 1.37, and for all hemlock–fir, −1.76 and −1.42.
Reliability, presentation, and relationships among data from inventories of forest condition
Authors: Innes John L. , Boswell Roger C.
Published: January 2008

Analysis of the variation within and between stands indicates that the variation is greater between stands than within. However, within-stand variation can be significant and should be taken into account when determining the number of trees to be sampled per stand. In even-aged, predominantly single-species stands, 24 trees may be insufficient to characterize the condition of the trees in the stand. The simplest and most commonly used method of presenting the results of annual assessments is cumulative bar charts of crown density. Tables documenting the change in crown densities from one year to the next of trees in a given crown density class provide more useful information and are recommended. Assessments of forest condition normally only record crown density and crown discoloration. Neither of these symptoms is specific to any particular cause. It is possible to record a wide variety of features when assessing the health of a tree. Generally, either crown density or crown discoloration (or both) is correlated with many other symptoms of poor condition within the crown. However, there are considerable differences between species. For example, crown density is more useful for the assessment of Norway spruce than for Sitka spruce. Although crown density and discoloration provide much useful information, collection of data related to other symptoms is required.
Productivity performance of the Canadian pulp and paper industry
Authors: Frank David L. , Ghebremichael Asghedom , Oum Tae H. , Tretheway Michael W.
Published: January 2008

This paper analyzes the productivity performance of the Canadian pulp and paper industry for the 1963–1984 period. The industry's productivity is first measured, then its sources are analyzed. Total factor productivity is used to measure industry productivity, and statistical estimation of neoclassical cost functions are used to determine sources of the productivity changes. In addition to decomposing the productivity changes into technical changes and changing the scale of the industry's output and capacity utilization, an attempt is also made to assess the impact of pollution control expenditures. The paper finds that although labour productivity grew at 2.5% per year (modest in comparison to other industries), the gross total factor productivity grew only by 1.2% per year. This is largely due to the fact that capital investment raises labour productivity but retards overall productivity. Of the 1.2% growth in total factor productivity, 0.88% was due to the increased scale of the industry output and 0.32% to technical change. Although there is no statistically conclusive evidence, the point estimate indicates that pollution control expenditures may have retarded productivity growth. However, this subject requires further investigation.
Transplanted red oak seedlings mediate transplant shock by reducing leaf surface area and altering carbon allocation
Authors: Struve Daniel K. , Joly Robert J.
Published: January 2008

One-year-old red oak seedlings (Quercusrubra L.) from three open-pollinated families were produced in 1 m tall containers during 1989. In spring 1990, the seedlings were either transplanted (which included pruning the main root to a 15-cm length) or not. Transplanted seedlings either received a 5-s basal dip in 20 mM indole-3-butyric acid or did not. The seedlings were placed in a greenhouse and harvested at the beginning of the first lag phase, at the beginning of elongation of the second growth flush, and 70 days after the beginning of the experiment. Root-pruning removed 42 to 50% of whole-plant dry weight. Transplanted seedlings had significantly reduced leaf surface area and began a second growth flush later than untransplanted seedlings. There were no treatment differences in CO2 assimilation rate on a per unit leaf surface area. Predawn xylem water potential in transplanted seedlings was lower than in untransplanted seedlings. Transplanted seedlings used less root and more shoot reserves to develop the first flush than untransplanted seedlings. Treating root-pruned seedlings with 20 mM indole-3-butyric acid did not significantly increase growth potential compared with untreated transplanted seedlings. For transplanted red oak, transplant shock seems to be mediated through reduced leaf surface area, which reduces whole-plant water use.
Fine-root growth and chemical composition in declining Central Ontario sugar maple stands
Authors: Adams Cindy M. , Hutchinson Thomas C.
Published: January 2008

This study examines the condition of fine-root systems of healthy and declining sugar maples (Acersaccharum Marsh.) at two sites in Central Ontario, one moderately declining and the other severely declining. Roots are frequently sensitive indicators of soil nutrition, thus ingrowth cores (soil transplants) were used to assess the effect of bulk surface (F-layered Ah horizon) soils collected from beneath healthy or declining trees on fine-root chemistry and growth. Soil at each site was collected from healthy and declining trees and reciprocally transplanted (buried) in mesh bags, and roots were allowed to grow into the soil cores for 8 weeks. In addition to transplants of untreated soils, additional transplants of "healthy" and "decline" soils treated by either (i) steam sterilization to remove pathogens or (ii) fertilization with superphosphate were made. Root dry weight of healthy and declining trees was reduced 25–70% in untreated decline soils compared with healthy soils (p ≤ 0.007). This was consistent with lower Ca, Mg, Mn, and Fe in the soil solution of declining trees at the severely declining site and a lower Mn concentration and Ca/Al and Mg/Al ratios in the soil solution at the moderately declining site. Compared with roots of healthy trees, roots of declining trees had significantly lower Ca concentrations for both stands, and in addition, significantly lower concentrations of P, Mg, S, K, Mn, Al, Fe, and Zn in the more severely declining stand. The experimental soil transplants established that lower nutrient concentrations in soils from declining trees are reflected in the chemistry of roots growing in them. On the whole, the fertilizer treatment significantly increased root growth and the steam sterilization treatment had no effect on root growth. While this study shows that reduced nutrient availability in the rooting substrate is an important factor in decline, it is not known how recently this nutrient depletion has occurred, nor what is the cause. Although other mechanisms may be involved, reduced nutrient availability in the rooting substrate is consistent with the speculation that deposition of acidic salt solutions of sulphate and nitrate to these forest soils has caused accelerated soil base cation leaching losses that are reflected in nutritional deficiencies and growth decline.
Temporal differences in genetic diversity and structure of sugar maple in an old-growth forest
Authors: Foré Stephanie A. , Hickey R. James , Guttman Sheldon I. , Vankat John L.
Published: January 2008

Genetic data were collected for five developmentally based cohorts of Acersaccharum Marsh in a large southwestern Ohio nature preserve. A minimum of 48 individuals were sampled from each of the following cohorts: embryos, 1st-year seedlings, and three diameter at breast height classes (≤ 2, 15–25, and ≥ 40 cm). Genotypes at eight loci were inferred from phenotypic enzyme patterns of seven enzymes extracted from cambial tissue and resolved by starch gel electrophoresis. Allelic data were subdivided by cohort and statistically compared. There was no significant difference in observed heterozygosity among the cohorts. Nei's gene diversity statistics, Nei's unbiased genetic distance, and χ2 analyses of allele and genotype frequency heterogeneity indicated that there was little genetic differentiation among cohorts. The observed differentiation resulted from allele and genotype frequency differences between seedlings and other cohorts.
Predicting the effects of hardwood competition on red pine seedling growth
Authors: White Alan S. , Elliott Katherine J.
Published: January 2008

Pin cherry (Prunuspensylvanica L.f.) and striped maple (Acerpensylvanicum L.) are potentially important competitors of red pine (Pinusresinosa Ait.) planted on recently clear-cut hardwood sites. By experimentally manipulating initial competitor densities on 2.0-m2 plots, we were able to quantify and compare the effects of competitor species on red pine seedlings 2 years after planting on two sites in western Maine. Various measures of competitor biomass and leaf area index (LAI) were highly correlated; thus, we used LAI to quantify competitor abundance. On the site with poorer growth for both competitors and red pine, the only red pine variable significantly correlated with competitor LAI was specific leaf area (SLA) of current needles. On the site with better growth for all species, various measures of red pine biomass as well as diameter at ground level and SLA were significantly correlated with competitor LAI. Seedling height was not significantly correlated with competitor LAI at either site. Although there were no significant differences between competitor species in terms of their effect per unit of LAI, pin cherry tended to achieve much higher LAI (and biomass) than did striped maple and thus had a greater negative impact on red pine seedling growth. We conclude that general predictions of the early effects of competition under field conditions are possible, but that the strength of the relationships may be influenced by the extent to which microsite factors and site characteristics are incorporated.
Biomass and nutrient content of Douglas-fir logs and other detrital pools in an old-growth forest, Oregon, U.S.A.
Authors: Means Joseph E. , MacMillan Paul C. , Cromack Jr. Kermit
Published: January 2008

Logs, forest floor, and mineral soil were sampled and measured, and snags were measured, in a 450-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand on the H.J. Andrews Experimental Forest, Oregon. Logs, some still identifiable after 300 years on the forest floor, contained large amounts of organic matter (222 Mg/ha), C (100 Mg/ha), water (559–10 700 L/log), N (183 kg/ha), and Ca (141 kg/ha), and smaller amounts of P (5.5 kg/ha), K (22 kg/ha), Mg (14 kg/ha), and Na (3.7 kg/ha). Logs and snags covered about 17% of the forest floor and had an all-sided area index of 0.69 m2/m2. Through mineralization, C, N, and K were lost through time; Ca and Mg increased; and P and Na increased then decreased, showing no net change. Also through mineralization, cellulose and hot acid detergent soluble fraction decreased more rapidly than lignin. Lignin was apparently not lost until the later stages of decay, when N was also lost in significant amounts. This parallels the shift from initial dominance by white rots that degraded cellulose and lignin to later dominance by brown rots that preferentially degraded cellulose. Lignin and cellulose were eventually lost at more similar rates in later decay stages. This may have been due in part to a close association between the remaining cellulose and lignin in later decay stages. Lignin was a better predictor of the onset of N release than was the C:N ratio.
Changing carbohydrate profiles in shortleaf pine (Pinusechinata) after prolonged exposure to acid rain and ozone
Authors: Paynter Valerie A. , Reardon John C. , Shelburne Victor B.
Published: January 2008

Shortleaf pine (Pinusechinata Mill.) seedlings grown in open-top chambers were exposed to several combinations of ozone (near zero, ambient, 1.7 × ambient, or 2.5 × ambient) in conjunction with acid rain (pH 3.3, 4.3, or 5.3) starting in August 1988. Needle samples from the first (89-1) and third (89-3) flushes of the 1989 growing season were analyzed for their glucose, sucrose, total reducing sugars, and starch contents. For the 89-1 flush (current-year needles), no differences in glucose, sucrose, or starch contents were observed among the various ozone exposures during 1989. However, needles exposed to 2.5 × ambient ozone exhibited higher levels of total reducing sugars compared with other ozone exposures for most of 1989. High H+ concentration (pH 3.3) increased glucose content (compared with pH 4.3 or 5.3) in the September sampling only. No significant differences were observed among ozone treatments for the total reducing sugars, glucose, or starch contents of the 89-3 flush (previous-year needles) for most of the sampling periods in 1990. However, the sucrose content was lower in needles receiving 2.5 × ambient ozone compared with other ozone exposures. Although high H+ concentration (pH 3.3) appeared to affect some carbohydrate components, there was no general trend observed.
Le système radiculaire dans les érablières du Québec. II. Le développement radiculaire en relation avec le microrelief et la roche mère
Authors: Badibanga B. , Pagé F. , Sauvesty A. , Ansseau C.
Published: January 2008

The root systems of two sugar maple groves, one on acidic parent material, the other on calcareous parent material, were studied in Quebec. The microrelief of both sites consisted of bumps and holes. Bumps represented 65% of the area. On acidic parent material, the roots > 1 cm in diameter were more than 5 m long. On calcareous parent material, they rarely exceeded 4 m in length. These larger roots branched out into many smaller roots in all directions in the bumps, and in the upper soil horizons of the holes. In the acidic site, the rootlet mass was smaller (about 16 t•ha−1) than that observed in calcareous site (about 19 t•ha−1). In both sites, rootlet mass was higher in the bumps (14–17 t•ha−1) than in holes (2–4 t•ha−1). In bumps, 80 and 69% of these rootlets grew in the B horizons in acidic and calcareous sites, respectively. In the holes, rootlets were concentrated (> 65%) in the F and Ah horizons. In the acidic site, rootlets < 0,5 mm in diameter were longer, more entangled, and more densely packed (7–11 mg•cm−3) in the F and Ah horizons than in the B horizons (1–2 mg•cm−3); F and Ah horizons of the bumps also produced the highest density of rootlets < 0,3 mm in diameter (about 50 and 20 mg•cm−3, respectively). In the other horizons of this site, as well as in all horizons of the calcareous site, the rootlets were short and developed in tufts. In the calcareous site, rootlets < 0,3 mm in diameter were less abundant in the Ah horizons of bumps (about 10 mg•cm−3). This site contained more rootlets 1–2 mm in diameter than the acidic site.
Variation in susceptibility of Eucalyptusglobulus provenances to Mycosphaerella leaf disease
Authors: Carnegie A.J. , Keane P.J. , Ades P.K. , Smith I.W.
Published: January 2008

Quantitative assessments of the incidence and severity of Mycosphaerella leaf disease were made on nine provenances (encompassing the four subspecies) of Eucalyptusglobulus Labill. over three seasons in 1990 in a trial in Victoria, Australia. Defoliation was also assessed and tree height and diameter measured. Mycosphaerella leaf disease increased rapidly from winter to spring with disease incidence reaching 100% in most provenances by summer. There were highly significant differences in disease severity among provenances, with provenances from E. globulus ssp. globulus Kirkpatrick and E. globulus ssp. bicostata (Maid, et al.) Kirkpatrick being the most severely affected, while provenances from E. globulus ssp. maidenii (F. Muell.) Kirkpatrick and E. globulus ssp. pseudoglobulus Kirkpatrick were only slightly affected. There were also highly significant differences among provenances within E. globulus ssp. globulus and E. globulus ssp. pseudoglobulus. There was a high correlation between disease severity in summer and defoliation, suggesting that Mycosphaerella leaf disease was the main causal agent in leaf fall. There was also a high negative correlation between disease severity and growth rate. This study shows the potential benefits of selecting resistant provenances of E. globulus to maximise production from plantations in areas where Mycosphaerella leaf disease is a problem.
Variation in forest inventory field measurements
Authors: McRoberts Ronald E. , Hahn Jerold T. , Hefty Glenda J. , Cleve Jerry R. Van
Published: January 2008

Field crews from the North Central Forest Experiment Station independently measured two forest inventory plots in Michigan's Upper Peninsula; one plot was measured by eight crews and the other was measured by nine different crews. For 61 trees, the variation in measurements of diameter at breast height (DBH), crown ratio, and site index is described. For DBH, the distribution of field crew mistakes and the distribution of measurements without mistakes are described separately. For crown ratio, the distribution of differences between individual estimates and the most frequently occurring estimate for corresponding trees is described. For site index, the distribution of differences between individual estimates and the mean of plot estimates is described. Coefficients of variation were less than 5% for DBH, approximately 73% for crown ratio, and 13% and 16% for site index for the two plots. The effects of variation in measurements on 20-year predictions of basal area and cumulative basal area growth were estimated for the two plots using STEMS, TWIGS, and Monte Carlo simulations. Coefficients of variation were 2% and 3% for basal area and 7% and 9% for cumulative basal area growth for the two plots. Variation in site index estimates had the greatest effect on variation in the output variables.
Soil moisture as a predictor of methane uptake by temperate forest soils
Authors: Castro Mark S. , Melillo Jerry M. , Steudler Paul A. , Chapman Jon W.
Published: January 2008

We conducted soil moisture manipulation experiments in a red pine (Pinusresinosa Ait.) plantation at the Harvard Forest (Petersham, Mass.) in August 1992 and May 1993. To manipulate soil moisture, we added 10 cm of groundwater to 1-m2 plots and allowed the soils to dry down to their pretreatment moisture contents. We measured methane (CH4) flux, soil moisture, and temperature prior to and after the water addition. Soils in both the control and watered plots were usually sinks for atmospheric CH4. Average consumption rates by control soils ranged from 0.12 to 0.17 mg CH4-C•m−2•h−1. Methane consumption rates by watered soils ranged from 0 to 0.12 mg CH4-C•m−2•h−1 and were inversely related to the moisture content of the upper 10 cm of mineral soil. Linear regression between soil moisture and CH4 consumption explained 78% of the variability (CH4 consumption = 0.001 75 (percent water filled pore space)–0.1957). Using this empirical relationship, we predicted CH4 consumption by soils at three other locations in the Harvard Forest, which agreed closely (r2 = 0.7574) with rates measured in the spring, summer, and fall of 1988–1992. Results from our study suggest that soil moisture is a good predictor of methane uptake by these forest soils and may be used to predict how future changes in soil moisture resulting from alterations in regional precipitation patterns will affect the strength of this terrestrial CH4 sink.
Coarse woody debris and forest floor respiration in an old-growth coniferous forest on the Olympic Peninsula, Washington, USA
Authors: Marra James L. , Edmonds Robert L.
Published: January 2008

Carbon dioxide evolution rates for downed logs (coarse woody debris) and the forest floor were measured in a temperate, old-growth rain forest in Olympic National Park, Washington, using the soda lime trap method. Measurements were taken every 4 weeks from October 22, 1991, to November 19, 1992. Respiration rates for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and western hemlock (Tsugaheterophylla (Raf.) Sarg.), logs were determined for decay classes 1–2, 3, and 5 in two diameter classes. Overall, western hemlock logs respired at a rate 35% higher (4.37 g CO2•m−2•day−1) than Douglas-fir logs (3.23 g CO2•m−2•day−1). Respiration rates for decay class 1–2 logs of both species were similar to decay class 5 logs (4.46 and 4.07 g CO2•m−2•day−1, respectively), but decay class 3 logs respired at a lower rate (3.23 g CO2•m−2•day−1). Seasonal patterns of respiration rates occurred, particularly for decay class 1 and 2 western hemlock logs where monthly averages ranged from a low of 2.67 g CO2•m−2•day−1 in February 1992 to a high of 8.30 g CO2•m−2•day−1 in September 1992. Rates for decay class 1–2 western hemlock logs were greater than those from the forest floor, which ranged from 3.42 to 7.13 g CO2•m−2•day−1. Respiration rates were depressed in late July and August compared with fall and spring owing to the summer drought characteristic of the Pacific Northwest. Large-diameter western hemlock logs in decay class 1–2 had higher respiration rates than small-diameter logs, whereas large-diameter decay class 3 western hemlock logs had lower respiration rates than small-diameter logs.
Intratree and intertree variation in selected wood quality characteristics of European oak (Quercuspetraea and Quercusrobur)
Authors: Zhang S.Y. , Nepveu G. , Owoundi R. Eyono
Published: January 2008

Twenty-three trees of European oak (Quercuspetraea (Matt) Liebl. and Quercusrobur L.) were collected from northeastern France to study intratree and intertree variation in the following characteristics: (i) wood density as well as earlywood density and latewood density; (ii) various types of wood shrinkage; and (iii) ring width and its components. Both intratree variation and intertree variation in the three characteristics are significant, but intertree variation is generally smaller. However, the relative magnitude of intertree variation varies with characteristic: intertree variation accounts for about 40% of the total variation in radial, tangential, and volumetric wood shrinkage, 32.5% of the total variation in ring width, and 12.6% of the total variation in wood density. Furthermore, the intertree variation is closely and positively related to the intratree variation: among the three characteristics studied, both intertree variation and intratree variation were highest for ring width and its components, and lowest for wood density and its components. In addition, intratree variation increased remarkably with increasing tree age in these species. In general, intratree variation in wood density and wood shrinkage depends more on cambial age than on ring width. The present study, together with the information available so far, suggests that the quality of European oak wood could be significantly improved.
Chloroplast DNA diversity of Douglas-fir in British Columbia
Authors: Ponoy Bundit , Hong Yong-Pyo , Woods Jack , Jaquish Barry , Carlson John E.
Published: January 2008

The level of chloroplast DNA (cpDNA) diversity was estimated among individuals, populations, and geographic regions of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in British Columbia by analyzing restriction fragment length polymorphisms (RFLP) from 18 populations covering the three geographic regions (coast, transition zone, and interior). Four sets of pooled probes, consisting of four to eight cpDNA clones from lodgepole pine (Pinuscontorta Dougl. ex Loud.), were used as hybridization probes for RFLP analysis. Thirty cpDNA restriction fragments out of a total of 175 observed fragments were detected to be polymorphic in all four sets of hybridization probes. Sixteen haplotypes were characterized among all of the Douglas-fir populations. The transition region showed the highest level of total genetic diversity (0.853) and genetic diversity within populations (0.762) of the three regions. The highest degree of population differentiation was found in the interior region (0.193). A higher proportion of the genetic diversity was allocated within populations than among populations in all three regions. Only 11–19% (mean 14.6%) of the total genetic diversity within geographic regions is due to interpopulation genetic diversities. The distribution of cpDNA diversity in sampled B.C. Douglas-fir is concordant with a typical pattern for long-lived woody species as observed in allozyme studies.
Effect of companion species on the growth of jack pine (Pinusbanksiana)
Authors: Longpré Marie-Hélène , Bergeron Yves , Paré David , Béland Martin
Published: January 2008

The growth and yield of jack pine (Pinusbanksiana Lamb.) was studied in even-aged stands of three types: pure jack pine, jack pine mixed with paper birch (Betulapapyrifera Marsh.), and jack pine mixed with trembling aspen (Populustremuloides Michx.) growing on moderately well-drained glaciolacustrine clay soils in the southern tip of the Clay Belt of northwestern Quebec. Site index, average DBH, and average height of jack pine, and the availability of nutrients in the forest floor were compared among stand types. No differences were found in the height growth of jack pine among stand types. However, diameters of jack pine in mixtures with paper birch were significantly greater than in either pure stands or in mixtures with aspen despite the fact that both mixed stand types showed higher forest floor pH and greater concentrations of exchangeable calcium and magnesium than the pure stands. These results, together with the pattern of height growth of the three species, suggest that the beneficial effect of paper birch on the diameter growth of jack pine is caused mainly by a reduction in the competition for light among individual jack pine trees. The silvicultural implications of the results are discussed.
Genetic variation in cambial phenology of coastal Douglas-fir
Authors: Li Peng , Adams W.T.
Published: January 2008

The objectives of this study were to (i) determine the extent of genetic variation and genetic control of cambial phenology in coastal Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco), (ii) assess the degree to which cambial phenology is genetically related to bud-burst timing, (iii) examine genetic relationships between cambial phenology and growth traits, and (iv) evaluate the potential for indirectly altering cambial phenology in breeding programs when selection is for stem volume. Dates of diameter-growth initiation and cessation, and duration of diameter growth (i.e., cambial phenology traits), as well as diameter increment for a single growing season (1987, at the age of 15 years from seed), were estimated from cumulative diameter growth curves of individual trees of 60 open-pollinated families growing in one plantation. Data on stem height and diameter (DBH), and date of bud burst in 1987 were also collected. Dates of diameter-growth initiation and cessation differed significantly among families, but had lower estimated individual heritabilities (≤0.23) than date of bud burst (0.87). Weak genetic correlations between date of bud burst and dates of diameter-growth initiation and cessation (range −0.09 to 0.26) indicate that timing of diameter growth cannot be reliably predicted from observations on the more easily measured bud burst. Cambial phenology traits were weakly correlated with 1987 diameter increment and moderately correlated with 15-year DBH and volume. Selection of parents in this study for stem volume at age 15 and subsequent crosses among them, would be expected to lead to earlier initiation of diameter growth in the offspring, and possibly later cessation as well. The practical implications of these indirect responses in terms of increased risk of frost damage are unclear, since projected changes are small (i.e., a few days).
Genetic relationships between wood density components and cambial growth rhythm in young coastal Douglas-fir
Authors: Vargas-Hernandez Jesus , Adams W.T.
Published: January 2008

To better understand the genetic control of wood formation in coastal Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco), and to assess the potential impact of selecting for increased wood density on adaptation of trees, genetic relationships of wood density, and its components, with cambial growth rhythm traits were examined in a 15-year-old progeny test. Timing of diameter growth during the 1987 growing season was available from an earlier study, and wood formation traits were estimated by X-ray densitometry of increment core samples. Wood formation traits were under weak genetic control [Formula: see text]. Lengths of earlywood and latewood formation were mostly determined by the timing of latewood transition. Overall core density was negatively correlated with the dates of cambial growth initiation (rA = −0.41) and latewood transition (rA = −0.62), and positively correlated with the date of cambial growth cessation (rA = 0.40). As a result of these relationships, higher wood density was associated with a longer duration of cambial growth (rA = 0.67) and a slower rate of wood formation (rA = −0.37). All density components showed similar relationships with cambial phenology and wood formation traits. Selection for increased wood density is expected to cause only a slight extension of the cambial growth period, but it would also cause an earlier transition to latewood formation, negatively affecting growth rate.
Fungal sporocarp mediated losses of Ca, Fe, K, Mg, Mn, N, P, and Zn from conifer logs in the early stages of decomposition
Authors: Harmon Mark E. , Sexton Jay , Caldwell Bruce A. , Carpenter Steve E.
Published: January 2008

The export of mass and nutrients associated with the formation of fungal sporocarps during the first 7 years of decomposition of logs of four conifer species (Abiesamabilis Dougl. ex Forbes, Pseudotsugamenziesii (Mirb.) Franco, Thujaplicata D. Don, and Tsugaheterophylla (Raf.) Sarg.) was investigated in western Oregon. Abundance of the most common fungal species, Naematolomacapnoides (Fr.:Fr.) P. Kumm, differed significantly with log species; the fungus was most abundant on Abies and least abundant on Thuja. Fungi increased concentrations of N, K, and P over those found in associated logs by as much as 38, 115, and 136 times, respectively. Thus, a fair proportion of the initial N (0.9–2.9%), K (1.8–4.5%), and P (1.9–6.6%) was transported out of logs via sporocarps at a time when immobilization would have been predicted from critical element ratios (e.g., C/N).