bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of juvenile wood in two stems of Larixlaricina
Authors: Yang K. C. , Benson C. A. , Wong J. K.
Published: February 2008

The distribution and vertical variation of juvenile wood was studied in an 81-year-old dominant tree and an 83-year-old suppressed tree of Larixlaricina (Du Roi) K. Koch. Two criteria, growth ring width and tracheid length, were used to demarcate the boundary of juvenile wood. The width of juvenile wood, expressed in centimetres and the number of growth rings, decreased noticeably from the base to the top of the tree. The volume of juvenile wood decreased in a similar pattern. These decreasing trends had a strong negative correlation with the year of formation of cambial initials at a given tree level. The length of these cambial initials decreased with increasing age of formation of the cambial initials. In the juvenile wood zone, there was a positive linear regression between the growth ring number (age) and the tracheid length. The slopes of these regression lines at various tree levels increased as the age of the year of formation of the cambial initials increased. At a given tree level, the length of tracheids increased from the pith to a more uniform length near the bark. However, the number of years needed to attain a more uniform tracheid length decreased from the base to the top of the tree. These relationships suggest that the formation of juvenile wood is related to the year of formation of the cambial initials. Consequently, the juvenile wood is conical in shape, tapering towards the tree top.
The effect of elemental sulfur on certain chemical and biological properties of surface organic horizons of a forest soil
Authors: Maynard D. G. , Germida J. J. , Addison P. A.
Published: February 2008

Elemental sulfur is a by-product of sour natural gas processing in Alberta, Canada. Breakup and weathering of the storage elemental sulfur blocks has resulted in the deposition of large amounts of elemental sulfur into adjacent forest ecosystems. This has caused considerable damage to the understory vegetation. Certain chemical and biological properties of surface organic forests horizons (LFH) that have been exposed to elemental sulfur for several years were examined over a 2-year period. Increasing concentrations of elemental sulfur (4 100 to 50 400 mg S kg soil−1) and 1.0 M NH4Cl extractable S and decreasing pH (4.4 to 2.4) occurred in the LFH with increasing proximity (750, 250, and 50 m) to the elemental sulfur source. Thiobacillusthiooxidans appeared to be the main organism responsible for elemental sulfur oxidation in all LFH samples. The site immediately adjacent to the elemental sulfur block (50 m) showed reduced concentrations of total and 1.0 M NH4Cl extractable Ca, Mg, K, and Mn. In addition, in the 2nd year of sampling, CO2 respiration in nonamended and glucose-amended samples was significantly reduced. The other sites (250 and 750 m from the block) showed no significant decrease in nutrient status or heterotrophic microbial activity.
Seasonal patterns of net photosynthesis of loblolly pine from diverse origins
Authors: Boltz Brett A. , Bongarten Bruce C. , Teskey Robert O.
Published: February 2008

Growth and photosynthesis were examined in seedlings of Pinustaeda L. (loblolly pine) from six widely separated provenances. The seasonal patterns of net photosynthesis were similar for each. Seedling net photosynthesis peaked in late October and net photosynthesis per unit leaf area peaked before midsummer and again in late October. When averaged over the entire season, seedling photosynthesis was greatest for Florida seedlings and least for Arkansas–Oklahoma and Texas seedlings. Seedling photosynthesis was strongly correlated with final size on all sampling dates and when averaged over the entire season. Both leaf area and net photosynthesis per unit leaf area contributed to the differences among provenances. Late season growth and photosynthesis, observed in the Florida provenance, increased provenance differences established early in the growing season.
Foliar chemical concentrations, growth, and site productivity relations in western red cedar
Authors: Radwan M. A. , Harrington Constance A.
Published: February 2008

Important site and tree characteristics of western red cedar (Thujaplicata Donn ex D. Don) were examined in 19 natural stands in the coastal and interior zones of western Washington and Oregon, U.S.A., and in western Vancouver Island, British Columbia, Canada. The stands occurred at various elevations and on different soil types and differed in age, soil pH, and associated plant species. Current-year foliage was collected during the winter and concentrations of N, P, K, S, Ca, Mg, Fe, Mn, B, Zn, Cu, Mo, Al, and the chlorophylls were determined. Mean terminal growth during the previous 3 years and site index at 50-year breast-height age were calculated for each stand. Site index ranged from 18 to 26 m. Terminal growth and foliar concentrations of the macronutrients, micronutrients, Al, and the chlorophylls varied among the 19 sites and between the two zones. Compared with known values for the most common associated conifers, foliar concentrations of red cedar were especially low in Mn and Al and high in Ca and Mo. Site index was correlated positively with N, the chlorophylls, S, Cu, and B, and negatively with Fe and Al. Also, N was positively correlated with the chlorophylls and with some of the other nutrients; there were many correlations among the nutrients and between some nutrients and soil pH or stand age. The data obtained provide base-line information for future analytical work with red cedar foliage. In addition, results suggest that (i) nutrient management strategies in western red cedar stands may differ from those for other conifers and different strategies may be necessary for the coastal and interior zones, (ii) productivity of red cedar may be improved by cultural treatments, including fertilization, which would enhance levels of chlorophyll as well as some essential elements (N, S, P, B, and Mo) in the foliage, (iii) levels of some chemicals in the foliage, such as N, chlorophyll, S, and B, may be useful as indicators to assess site quality for red cedar production, and (iv) chlorophyll may be used as a simple means to estimate N status of red cedar.
Effect of timber harvesting on microbial biomass fluxes in a northern Rocky Mountain forest soil
Authors: Entry James A. , Stark Nellie M. , Loewenstein Howard
Published: February 2008

Microbial biomass and relative bacterial and fungal percentages were measured in organic forest soil from a Rocky Mountain site subjected to four harvesting treatments: RL, clear-cut and residue left; RR, clear-cut and residue removed; RB, clear-cut and residue burned; C, uncut control. Microbial biomass peaked in spring and fall regardless of treatment. Biomass in soil from the RB treatment was significantly (p < 0.05) less than that in soil from the other treatments most of the year; biomass did not significantly differ in soil from the RR and C treatments. During summer and winter, microbial biomass in soil from the RL treatment was significantly greater than that in soil from any other treatment, probably because of the large amount of organic residue left after harvest; moreover, this residue insulated the soil, preventing it from drying or freezing. At soil temperatures above 5 °C, microbial biomass correlated positively with soil moisture regardless of treatment; at soil temperatures below 2.5 °C, microbial biomass correlated positively with increasing soil temperature. During periods with snow cover, bacterial and fungal percentages were roughly equal regardless of treatment; during the rest of the year, bacterial percentages were high in the RL and RB treatments and low in the RR and C treatments. During periods without snow cover, bacterial and fungal percentages correlated positively with increasing soil pH; however, at near-freezing temperatures the percentage of bacteria and fungi seemed unaffected by soil pH. These findings suggest that treatments that remove a large portion of available site nutrients while reducing soil microbial activity could limit stand development.
Prescribed fire effects on mixed conifer forest structure at Crater Lake, Oregon
Authors: Thomas Terri L. , Agee James K.
Published: February 2008

Prescribed fire was applied to a mixed conifer forest in southern Oregon, part of which was selectively logged in the 1930's. Structural effects were measured over a 4-year postfire period. Initial tree mortality was concentrated in small diameter and height classes of Abiesconcolor (Gord. and Glend) Lindl., Pinuslambertiana Dougl., and Pinusponderosa Dougl. Most mortality in all three species after the 1st year was associated with bark beetles. Mortality after 1 year for Abiesconcolor remained primarily in smaller tree classes, while both small and large pines were killed. Implications for restoring natural conditions in these ecosystems include recognizing structural as well as process goals, while reintroducing fire, and recognizing the significance of available prescription variables in the prediction of fire effects.
Elm leaf scorch: abnormal physiology in American elms infected with fastidious, xylem-inhabiting bacteria
Authors: Kostka Stanley J. , Tattar Terry A. , Sherald James L.
Published: February 2008

Stem elongation, leaf area, xylem function, water relations, and stem starch reserves were compared between leaf scorch affected American elms (Ulmusamericana L.) infected with fastidious, xylem-inhabiting bacteria and symptomless trees. Stem elongation was significantly lower in elm leaf scorch affected trees than in symptomless trees, while no differences occurred in leaf area. Stem hydraulic conductivity in affected trees decreased from June through September, but increased during the same period in symptomless trees. Dye infiltration rates and number of functional vessels in stems collected from leaf scorch affected trees in September were significantly lower than in symptomless trees. Changes in stem water potential paralleled xylem infiltration rates. No differences in any measured parameters occurred between elm leaf scorch affected and symptomless trees in June prior to symptom onset. Once symptoms developed, stem water potential was more negative in affected trees than in symptomless trees. Mean stem starch levels were significantly higher in symptomless trees than in symptomatic trees. Results confirm that water deficit in leaf scorch affected trees may be attributed to xylem dysfunction possibly caused by bacterial occlusion. Growth reduction can be associated with decreased starch reserves induced by reduced water translocation and reduced effective photosynthetic area caused by the foliar necrosis of elm leaf scorch.
The sediment budget in severely disturbed watersheds, Queen Charlotte Ranges, British Columbia
Authors: Roberts Richard G. , Church Michael
Published: February 2008

Sediment budgets, averaged over one or more decades, have been estimated for four small (3.9 to l2.6 km2) drainage basins in the Queen Charlotte Islands for periods before and after clear-cut logging of 10 to 20% of the area, including stream banks. Data were obtained by field and photogrammetric measurements of sediment deposits supplemented by regional rate estimates for minor erosional processes. Landslides, riparian erosion, and soil creep are important sediment sources before logging, the former two dominating. Sediment production on hillslopes and delivery to stream channels may increase following logging, but not invariably. In each of the study basins, significant stream bank erosion following logging resulted in the accumulation of a substantial "wedge" of coarse sediment in the stream channel. Sediment transport through the channels has increased by up to 10 times; however, the residence time for the greatly increased volume of in-channel sediment has increased by up to 100 times. The in-stream sediment wedges are areas of persistently poor aquatic habitat. Their development was associated with obsolescent logging practices and they remain atypical.
Nutrient dynamics in the litter fall and forest floor of an 18-year-old loblolly pine plantation
Authors: Lockaby B. G. , Taylor-Boyd Jane Ellen
Published: February 2008

Dry weight and N, P, K, Ca, and Mg concentrations were monitored in the litter fall and forest floor of a loblolly pine (Pinustaeda) plantation in north Louisiana for 2 years. Dry weights of both litter fall and forest floor were statistically stable during the sampling period, possibly indicating steady-state conditions. A comparison of litter fall with forest floor weights indicated rapid decomposition (floor turnover = 1.5 years) relative to that of other loblolly pine systems.
Nitrogen fixation in cottonwood wetwood
Authors: Kamp B. J. van der
Published: February 2008

Samples of wetwood from four living western black cottonwood (Populustrichocarpa Torr. and Gray) trees growing near Vancouver, B.C., were incubated anaerobically with acetylene to detect nitrogen fixation using the acetylene-reduction method. Significant acetylene reduction was detected in all trees and ranged up to 5.16 nmol acetylene g–1 day−1. It is suggested that nitrogen fixation in wetwood may be a significant phenomenon in forest ecosystems.
Postcalibration sensitivity procedure for regressor variable errors
Authors: Gertner George
Published: February 2008

Random errors in the independent variables of a calibrated model can make predictions less precise. A method is given for approximating the precision of predictions when there are random errors in the postcalibration data. An example reveals that when independent variables are not error free, an "optimal" model can yield worse predictions than a "suboptimal" model.
Understanding log and stumpage prices in China: a primer for capitalist forest economists
Authors: Xu Zhihua , McKetta Charles W.
Published: February 2008

Log and stumpage price formation in the United States and China appear mathematically identical, but are radically different. In the United States, prices are derived from the demand for final wood products in competitive markets. In China, prices are set centrally based on direct costs of production. The system is borrowed from Russia and is based on a theory of labor value that ignores time and interest rates. We explore the existing Chinese price determination model and Chinese proposals to change it, as prices have had little relation to the value of wood in use or the cost of wood from other sources. A cost-based model has few incentives to minimize costs of production, but ignoring the cost of capital has made stumpage prices abnormally low. Both systems are products of different philosophies of value and evolution in pricing technology must occur in the context of the parent economy.
Lateral variability of forest floor properties under second-growth Douglas-fir stands and the usefulness of composite sampling techniques
Authors: Carter R. E. , Lowe L. E.
Published: February 2008

Lateral variability of forest floor physical and chemical properties is examined in LF and H horizons under six naturally regenerated, second-growth Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in coastal southwestern British Columbia. The number of samples required to predict a mean value at two confidence levels (P = 0.01 and 0.05) and two allowable errors (10 and 20%) are given for each variable. Total C, N, P, S, Zn, pH, and lipids were the least variable, requiring 2–13 samples to estimate a plot mean with a 10% allowable error at the 95% confidence level in LF horizons and 3–51 samples per lot in H horizons. Total K, Cu, and Mn were found to have moderately high lateral variability, while total Ca, Mn, Al, and Fe all required large numbers of samples to estimate the plot mean. In the second part of the paper, composite samples weighted by field depth and bulk density are compared with the depth and bulk density–weighted arithmetic mean of subsamples analyzed individually. Values from analysis of composite samples were within one standard deviation of the mean, with the exception of P and Cu in the LF horizons and lipids in both horizons. Composite values and mean values were significantly correlated across the six sites for all variables except lipids in LF horizons and total C and Mn in both horizons. Composite samples are suggested to provide an adequate estimate of the mean value of subsamples analyzed individually for most purposes and, for some variables (i.e., Ca, Fe, Al, and Mn), the only feasible method of obtaining an estimate of the mean.
Auxin stimulates lateral root formation of container-grown interior Douglas-fir seedlings
Authors: Simpson David G.
Published: February 2008

The effects of 1-napthaleneacetic acid (NAA) and 3-indolebutyric acid (IBA) soil drenches on lateral root formation and growth of interior Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) seedlings were studied. At rates between 10−3 and 10−5 M, NAA was more effective than IBA in stimulating first-order lateral root formation. Seedling age influenced the degree of NAA-induced lateral root formation. At three different nurseries the greatest number of lateral roots was produced by seedlings receiving 10−4 M (18.62 mgL−1) NAA 30 days after sowing. Shoot height and dry weight were reduced, although not at the expense of root growth in some cases.
Comparison of stochastic and deterministic mortality estimation in an individual tree based stand growth model
Authors: Weber Laura A. , Ek Alan R. , Droessler Terry D.
Published: February 2008

Long-term projections (100 years) were made using the deterministic and stochastic mortality algorithms of the STEMS individual tree based stand growth projection model. Deterministic versus averaged stochastic projection results showed no practical differences in mean stand values for number of trees, basal area, volume, or diameter distributions. The deterministic approach also eliminates the need for making repeated stochastic runs and averaging the results where interest lies only in mean projected values.
Use of crown ratio to improve loblolly pine taper equations
Authors: Valenti Michael A. , Cao Quang V.
Published: February 2008

Data from 278 trees felled in a loblolly pine (Pinustaeda L.) plantation were used to include crown ratio as a measure of tree form in a taper equation. The data were divided into 10 crown ratio classes. A segmented taper equation was fitted to each of the 10 classes to detect trends in the coefficients. Coefficients were then expressed as functions of crown ratio. The resulting three-segment taper equation with crown ratio as an additional independent variable was more flexible and provided more accurate predictions of upper stem diameters. Similar techniques were used to include crown ratio in a two-segment taper equation. The three-segment equation fitted the data better than the two-segment equation and provided superior taper predictions for the test data set.
Impact of feeding damage by snowshoe hares on growth rates of juvenile lodgepole pine in central British Columbia
Authors: Sullivan Thomas P. , Sullivan Druscilla S.
Published: February 2008

This study assessed the impact of snowshoe hare (Lepusamericanus Erxleben) feeding injuries on diameter and height growth of juvenile lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.). Five-year growth increments of undamaged and damaged crop trees in control (unspaced) and spaced stands, 20 km east of Prince George, B.C., were compared using analysis of variance. Semigirdling (sublethal) damage clearly suppressed diameter growth of small diameter (control, 41–60 mm; spaced, 31–50 mm) trees, but had little effect on larger stems. Height increment was significantly reduced by semigirdling in all diameter classes except for the 61–80 mm class in the control. Surface area or amount of bark and vascular tissue removed had little effect on growth increments in the spaced stand. The recommendation to delay spacing until the average tree diameter is >60 mm to avoid snowshoe hare damage is further supported for diameter but not necessarily for height growth.
Genetic and environmental variance in cone size, seed yield, and germination properties of black spruce clones
Authors: Stoehr M. U. , Farmer Jr. R. E.
Published: February 2008

Genetic and environmental variances in cone size, seed yield, and germination properties were evaluated for Piceamariana (Mill.) B.S.P. using material from ramets of 19 clones in a northern Ontario seed orchard. Thirty-seven percent of the variance in cone volume (mean, 2.2 cm3) was accounted for by differences among clones (range, 1.3–3.5 cm3) and 19% was accounted for by ramets within clones. Clone means for number of seed per cone ranged from 49 to 100 and averaged 71; 18% of seed was filled. Clonal variances for number of seed per cone and percent filled seed were 31 and 23% of the total variance, while ramets accounted for 18 and 13%, respectively. Germination of filled seed averaged 68% and clone means ranged from 28 to 90%. Sixty-seven percent of the variation in germination percent was due to clonal differences and 18% was associated with ramets.
Influence of hydraulic conductance of xylem on water status in cuttings
Authors: Ikeda Takefumi , Suzaki Tamio
Published: February 2008

not available
Paternal inheritance of chloroplast DNA in Douglas-fir
Authors: Neale David B. , Wheeler Nicholas C. , Allard Robert W.
Published: February 2008

The inheritance of chloroplast DNA in Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was determined using a restriction fragment length polymorphism (RFLP) as a marker. An insertion/deletion sequence homologous to a 15.3 kilobase PstI fragment from petunia chloroplast DNA was detected in SmaI and BamHI digests of total DNAs of parent trees. Full-sib progeny (36 in total) were then assayed for this polymorphism in three sets of crosses between male and female parents with different RFLP markers. The full-sib progeny had the same restriction fragment as the male parent, with three exceptions. These data provide direct evidence for the paternal inheritance of chloroplast DNA in a gymnosperm. This result is in sharp contrast to the strict maternal and occasional biparental inheritance of chloroplast DNA observed in angiosperms. The three exceptions had restriction fragments unlike either the male or female parents of the cross, suggesting that some type of mutational or recombinational event had occurred during the transmission of these genomes.
Tree uprooting: review of terminology, process, and environmental implications
Authors: Schaetzl Randall J. , Johnson Donald L. , Burns Scott F. , Small Thomas W.
Published: February 2008

Floralturbation, the mixing of soil by the action of plants, is an important pedologic process in forested areas. The uprooting of trees, the most obvious form of floralturbation, is a natural process found in nearly all forested landscapes. The term uprooting is distinct from such terms as treethrow, treefall, and blowdown, which imply processes that may occur without soil disturbance, as in bole snap. Uprooting is exacerbated by shallow rooting, topographic exposure, weakened condition of the tree, certain cutting practices, and (or) low soil cohesion and shear strength. The root plate of an uprooted tree may deteriorate into a pit-mound pair, the size and shape of which depends on the characteristics of the root plate and the amount of backward displacement during uprooting. This paper (i) provides a synthesis of related terminology on the topics of treefall and uprooting, (ii) examines various lines of evidence for the widespread occurrence of uprooting, (iii) summarizes disturbance cycles for catastrophic uprooting events in different environments, (iv) discusses several examples of the economic import and scale of widespread uprooting events, and (v) reviews environmental factors and silvicultural practices that may lead to increased uprooting or can be used to minimize its likelihood.
Autumnal photosynthesis is extended in nitrogen-fixing European black alder compared with white basswood: possible adaptive significance
Authors: Neave Ian A. , Dawson Jeffrey O. , DeLucia Evan H.
Published: February 2008

Net photosynthesis was measured at weekly intervals from late September to mid-November in the field on leaves of actinorhizal European black alder (Alnusglutinosa (L.) Gaertn.) and nonactinorhizal white basswood (Tiliaheterophylla Vent.) growing in central Illinois. Black alder retained its leaves and continued to photosynthesize for a month longer than white basswood. Maximum photosynthetic rates occurred in September and declined during the autumn for both species, although weekly values fluctuated widely. Mean maximum CO2 fixation rates for black alder and white basswood were 11.88 and 4.62 μmol CO2 • m−2 • s−1, respectively, at the initial measurement in late September. On each subsequent measurement date black alder had a significantly higher rate of CO2 fixation than basswood. Night temperatures of 0 °C and below caused a sharp decline in photosynthesis for black alder on the following day. Stomatal conductance was highly correlated with photosynthesis, but as these two parameters declined over the autumn, intercellular CO2 concentration increased. Thus, nonstomatal limitations are thought to be involved in the temperature-induced reduction in photosynthesis. Prolonged photosynthesis in autumn may give black alder a competitive growth advantage over other deciduous species, compensate for the high energy cost associated with nitrogen fixation, or be associated with black alder's inefficient conservation of foliar nitrogen via autumnal retranslocation.
Cycling of aluminum and nutrients in litterfall of a red spruce (Picearubens Sarg.) stand in Maine
Authors: Rustad Lindsey E. , Cronan Christopher S.
Published: February 2008

Annual and seasonal variations in the concentration and total return of Al, Fe, Mn, Ca, Mg, K, Na, C, N, and P in litterfall were studied for a period of 2 years in a mature red spruce stand in central Maine. Seasonal differences in elemental composition were large. The greatest change occurred in the autumn, when the concentrations of Al, Fe, N, P, and K declined, while Ca and Mg concentrations peaked. On an annual basis, litterfall contributed 0.5, 0.5, 1.1, 13.8, 2.1, 5.3, 0.2, 17.6, and 1.3 kg •ha−1•year−1 of Al, Fe, Mn, Ca, Mg, K, Na, N, and P, respectively, to the forest floor. The input of Al in litterfall was 10 times as great as that in net canopy throughfall, indicating that the biological cycling of Al in litterfall was an important source of Al to the forest floor at this site.
Origin of the phosphorus deficiency observed in declining sugar maple stands in the Quebec Appalachians
Authors: Paré D. , Bernier B.
Published: February 2008

To investigate the origin of the phosphorus (P) deficiency previously observed in declining sugar maple (Acersaccharum Marsh.) in several sites of the Quebec Appalachians, soils originating from 10 maple stands with foliar P concentrations ranging from 0.85 to 2.36 mg • g−1 were subjected to the following analyses: the chemical composition and P pools of L and F horizons, as well as pH, total nitrogen (N), exchangeable cations, total organic and inorganic P, P reserves fractionated according to their availability, and extractable iron (Fe) and aluminum (Al) of Ah (or H) and B horizons. The number of root tips per unit volume of soil was measured at 0–15 cm depth. Foliar P concentrations were positively correlated with P concentrations and P pools of L and F horizons, with the contents of readily available P fractions of the Ah or H horizon, and with the number of root tips to 15 cm depth. In contrast, foliar P concentrations and the available P fractions of the Ah or H horizon were negatively correlated with pH, with total P reserves, and with the concentrations of extractable Fe and Al and amorphous inorganic Fe of this horizon. The characteristics of the B horizon had little effect on P nutrition. It is concluded that under the conditions now prevailing in the Quebec Appalachians, the nature of the humus form may have a major influence on P nutrition of trees. Stands growing on soils with a moderately acid Ah horizon (mull) exhibited low foliar P concentrations, while those growing on soils associated with a mor humus had adequate P nutrition. A hypothesis is presented that may explain these unusual observations.
Logging of mature Douglas-fir in western Oregon has little effect on nutrient output budgets
Authors: Martin C. Wayne , Harr R. Dennis
Published: February 2008

Precipitation and streamwater quantity have been sampled continuously on three adjacent watersheds since 1964 at the H. J. Andrews Experimental Forest on the western slopes of the Cascade Mountains of Oregon. The chemistry of streamwater has been sampled since 1972, and the chemistry of precipitation since 1973. These watersheds were covered primarily by a mature 130-year-old forest of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). In 1974, one of the watersheds was clear-cut, the logs being removed primarily by a high-lead cable system. At the same time, 60% of the basal area was removed in a shelterwood cut from the adjoining watershed. The third watershed remained uncut for reference. Both harvested watersheds were broadcast burned in 1975 and planted to Douglas-fir in 1976. Streamwater chemistry data and input–output budgets for the three watersheds are presented for 10 years after cutting. Nitrate nitrogen was the only measured solute affected by logging. Despite a 30-fold increase, nitrate nitrogen concentrations were so low that more than twice as much nitrate nitrogen was added to the clearcut from precipitation as was lost in streamwater.
Postdormancy seed-cone development and the pollination mechanism in western hemlock (Tsugaheterophylla)
Authors: Colangeli Anna M. , Owens John N.
Published: February 2008

The development and function of the pollination mechanism is described for hemlock (Tsugaheterophylla (Raf.) Sarg.). Controlled pollinations at various stages following bud burst were used to define the period of maximum receptivity. Western hemlock has a pollination mechanism unlike that observed in other native conifers. The pollen grains were not taken into the micropyles; instead, the roughly sculptured pollen grains adhered to the long epicuticular wax covering the bracts. Seed cones became receptive to pollen soon after the bracts emerged from the bud scales and remained receptive until shortly before cone closure. Several days after the cones fully emerged beyond the bud scales, the ovuliferous scales elongated over the bracts, trapping the pollen between the bracts and scales. Several weeks after pollination, pollen germinated on the bracts and formed long pollen tubes which grew towards and into the micropyles.
Effect of different inbreeding levels on filled seed production in Douglas-fir
Authors: Woods J. H. , Heaman J. C.
Published: February 2008

Matings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were performed to develop inbreeding levels with inbreeding coefficient (F) values from 0.0 to 0.75. A strong inverse linear relationship was found between filled seed per cone and F at values ≤0.5. The following mean filled seed per cone values were obtained: outcross (F = 0.0), 31.6; half-sib cross (F = 0.125), 21.3; full-sib cross (F = 0.25), 16.7; parent–offspring backcross (F = 0.25), 15.5; self (F = 0.5), 1.2; second generation self (F = 0.75), 0.03. Parental effects on filled seed per cone were large, accounting for about 50% of the total variation. The use of related clones in a seed orchard will result in less inbred seed than expected under total panmixia, owing to decreased filled seed production at all inbred levels. Also, breeding programs will require increased effort to obtain seed when mating designs include crosses between related trees.
Efficacy of verbenone in reducing lodgepole pine infestation by mountain pine beetles in Idaho
Authors: Amman Gene D. , Thier Ralph W. , McGregor Mark D. , Schmitz Richard F.
Published: February 2008

Verbenone, a bark beetle antiaggregative pheromone, was deployed in lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) stands in the Sawtooth National Forest, Idaho, U.S.A., to test its efficacy in reducing tree losses to mountain pine beetle (Dendroctonusponderosae Hopkins). Treatments tested were verbenone, mountain pine beetle tree bait, verbenone plus mountain pine beetle tree bait, and a control. Each treatment was applied individually to 1-ha blocks and replicated four times. Treatment effects were measured by percentage of infested (i.e., mass-attacked) lodgepole pine. ANOVA showed a significant treatment effect (P < 0.005). Blocks treated with mountain pine beetle tree baits had significantly (P < 0.002) higher average percentages of infested trees (24.4%), whereas no significant difference occurred in percentages of infested trees among the other three treatments. Average percentages of infested trees were 0.9% for verbenone, 7.4% for verbenone plus mountain pine beetle tree bait, and 3.3% for the control. A 2.3-fold reduction in infested trees occurred when verbenone was applied to blocks treated with mountain pine beetle tree baits.
Reduction of mountain pine beetle (Coleoptera: Scolytidae) attacks by verbenone in lodgepole pine stands in British Columbia
Authors: Lindgren B. S. , Borden J. H. , Cushon G. H. , Chong L. J. , Higgins C. J.
Published: February 2008

The effect of the aggregation-inhibiting pheromone verbenone on mountain pine beetle attacks in lodgepole pine stands was assessed by affixing verbenone release devices on trees on a 10 × 10 m grid. In one experiment, aggregation to trees baited with an attractive combination of trans-verbenol, exo-brevicomin, and myrcene was reduced in verbenone-treated blocks compared with control blocks (attractive baits only). The mean number of trees with mass attacks (≥31.3 attacks/m2), mean percentage of available trees mass attacked, and mean total number of trees infested were reduced by 74.3, 66.7, and 58.5%, respectively. The ratio of 1987 attacks to 1986 attacks was reduced from 14.0 to 2.6. In a second experiment, using no attractive baits, verbenone caused similar but nonsignificant reductions. The mean number of trees with mass attacks, mean percentage of available trees mass attacked, and mean total number of trees infested were reduced by 75.2, 53.5, and 62.1%, respectively. The 1987 to 1986 attack ratio was reduced from 13.2 in control blocks to 0.2 in the verbenone-treated blocks, and the percentage of trees that were infested but not mass attacked was significantly increased, from 45.7% in the control blocks to 63.2% in the verbenone-treated blocks. We conclude that verbenone shows promise as a management tool for controlling the mountain pine beetle.
Phytomass and detrital carbon storage during forest regrowth in the southeastern United States Piedmont
Authors: Schiffman Paula M. , Johnson W. Carter
Published: February 2008

Carbon in soil, forest floor, and phytomass was estimated for two chronosequences of loblolly pine (Pinustaeda L.) plantations, as well as agricultural fields and natural Virginia pine (P. virginiana Mill.) forests. One plantation chronosequence was initiated on postagricultural fields and the other following clearing of natural second-growth pine forests and site preparation. Natural reforestation of old fields over 50–70 years increased carbon storage by about 235%, from about 55 000 to 185 000 kg/ha. Carbon in phytomass accounted for the greatest proportion of the increase (76%), followed by forest floor (13%) and surface soil (10%). Old field plantations stored more carbon than natural forests by approximately 42 000 kg/ha (22%). Virtually all of the gain was in phytomass. The contemporary practice of converting natural forests to plantations yielded only a modest gain in carbon (24%), and this in phytomass scheduled for harvest, not in detritus. The results showed negligible oxidative losses of carbon from soils after harvest and site preparation. Site preparation which includes burning may actually cause slow but long-term increases in detrital carbon as charcoal. Forest floor losses during conversion are largely regained by rotation end. Global carbon models need to be amended to incorporate these findings. Stabilization of the forest land base in the Piedmont foretells a rapidly declining capacity to store carbon at past rates. In terms of carbon gained, the current practice of converting natural forests to plantations is no substitute for the farm to forest conversions of past decades. Whether the southeastern United States Piedmont will continue to act as a net carbon sink depends largely on the balance between gains in detrital carbon, principally from charcoal produced by repeated site preparation, and the extent to which forest products from highly productive plantations are placed in long-term versus short-term storage.
Polycyclic growth and branching in the upper crown in provenances of lodgepole pine
Authors: O'Reilly Conor , Owens John N.
Published: February 2008

The percentage of shoots that originated from polycyclic growth in first-order branches and branch numbers in upper annual segments of leader growth were determined from trees of seven provenances of Pinuscontorta Dougl. ssp. latifolia Engelm. from British Columbia and the Yukon, growing in a provenance trial at Prince George, B.C. The number of first-order branches varied among provenances and year of growth and was related to the frequency of extra cycles. The percentage of polycyclic shoots was greatest in the 2nd to 4th years of branch growth, although this varied with year and provenance. Total branch numbers were influenced mostly by variation in first- and second-order branch numbers. Second-order branch numbers were greatest in the second and third segments of leader growth (from the top down), but this was influenced by year of growth and provenance. The high levels of second-order branching corresponded to the greater frequency of polycyclic branches in these positions. The fast-growing southern provenance had the most branches, while the slow-growing Yukon source had the least. The slower-growing provenances had the most first-order branches per unit height.
The phenology and spore dissemination patterns of Uredinopsismirabilis on Abiesbalsamea and Onocleasensibilis
Authors: Mazzola M. , Bergdahl D. R.
Published: February 2008

Phenology and spore dissemination patterns of Uredinopsismirabilis (Peck) Magnus were monitored from 1982 to 1984 in the Champlain Valley and north central Vermont. Teliospore germination began as early as May 5 and basidiospore dissemination continued as late as the week of June 17. Maximum basidiospore dissemination occurred after measurable precipitation. Infection of Abiesbalsamea (L.) Mill, occurred between May 19 and 30. Pycnia were apparent on current-year needles of A. balsamea by the week of June 17. Aeciospore development was observed by the week of June 24 and dissemination of aeciospores was completed about July 29. Aeciospores were trapped at highest concentrations during precipitation events. During dry periods, aeciospore dissemination showed a diurnal periodicity, with most spores trapped in the late morning hours. Uredia were formed on Onocleasensibilis L. as early as July 28 and urediniospores were trapped as late as October 4. Teliospores were formed in host tissues as early as July 7.
Stem deformation in Pinusradiata associated with previous land use
Authors: Carlyle J. C. , Turvey N. D. , Hopmans P. , Downes G. M.
Published: February 2008

Pinusradiata may exhibit moderate to severe stem deformity (Toorour syndrome) when planted on ex-pasture sites in southern Australia. However, the deformity does not occur on ex-eucalypt forest sites unless N fertilizer is applied. While the symptoms of Toorour syndrome are visually similar to those induced by Cu deficiency, the syndrome is associated with high foliar Cu concentrations (and concentrations of Mn and Zn). Furthermore, although Cu-deficient trees typically exhibit lower stem lignin concentrations than nondeformed trees, there is no apparent reduction in the stem lignin concentrations of trees exhibiting Toorour syndrome. Unlike Cu deficiency, the syndrome is not alleviated by Cu fertilizer applications. From comparisons of soil chemical properties between ex-pasture (deformed) and ex-eucalypt (nondeformed) sites, across a range of soil types and lithologies, it is concluded that (i) the syndrome is associated with previous land use rather than soil type or lithology, (ii) the syndrome is associated with the high fertility of ex-pasture soils, in particular, high NO3-N production, relative nitrification, and Mn availability, and (iii) it is unlikely that the syndrome is a consequence of single trace element or other element deficiencies.
Two dynamic programming algorithms for forest fire resource dispatching
Authors: Kourtz Peter
Published: February 2008

The dispatch of water bombers and fire-fighting crews to newly reported fires is an important task carried out by modern regional forest fire management centres. The problem of bomber dispatch involves the use of aircraft of varying speeds, cost, and fire-fighting effectiveness. Candidate aircraft for dispatch can be situated at remote attack bases or at ongoing fires. The problem of crew dispatch also involves candidate crews situated at remote attack bases or at ongoing fires, but unlike bomber dispatch, helicopter transport must be arranged. A transport helicopter must be flown to the specific crew's location and then to the fire. A helicopter is permitted a second trip to pick up an additional crew. The bomber- and crew-dispatch problems have both been formulated as dynamic programming algorithms. The bomber formulation closely resembles the traditional "knapsack" formulation. The crew and helicopter dispatch problem involves a more general formulation. Both algorithms are illustrated by simple examples. FORTRAN programs have been written for both algorithms. These programs are embedded within a large expert system which defines the desired bomber force and number of crews to be dispatched to a specific fire. This system is presently being tested at the North Central Regional Fire Centre of the Ontario Ministry of Natural Resources, located at Thunder Bay. It is expected that this system will undergo several years of testing and modifications before it is considered operational. Recent trials at the Thunder Bay fire centre have demonstrated the potential of the expert system, including the two dynamic programming algorithms, by matching or exceeding the dispatching performance of the dispatchers.
Historical trends in tree-ring growth and chemistry across an air-quality gradient in Wisconsin
Authors: Frelich L. E. , Bockheim J. G. , Leide J. E.
Published: February 2008

Basal-area increment and chemical composition of xylem wood were measured in three old-growth (ca. 75–100 years) white pine (Pinusstrobus L.) and three sugar maple (Acersaccharum) Marsh.) stands across a pH and SO4 gradient in precipitation in Wisconsin. In 1986 the volume-weighted mean pH and SO4 content of precipitation ranged from 4.5 to 5.0 and from 21 to 11 kg • ha−1, respectively, from southeastern to northwestern Wisconsin. With one exception (a white pine site at Point Beach in eastern Wisconsin), basal-area increment increased from the 1890s until the 1950s (sugar maple) or 1970s (white pine), then levelled off. Growth efficiency, estimated as the ratio of basal area to exposed crown area or crown volume for the 1980–1985 period, was similar for sugar maple across the gradient; however, growth efficiency of white pine was lower at Point Beach than at the two northern Wisconsin sites. Lead concentrations in xylem wood of both species have increased with time, except at Crotte Creek in northwestern Wisconsin, and Pb concentrations in xylem wood of both species were significantly greater in southeastern than in northwestern Wisconsin. Sulfur concentrations in xylem wood of white pine have increased since the 1960s at Point Beach and at one site in north central Wisconsin; S concentrations are significantly greater for both species in southeastern than in northern Wisconsin. Concentrations of Ca, Mg, and K in xylem wood of sugar maple have decreased over the past century. Whereas xylem wood concentrations of Mn and Zn generally show no age-related trends, Fe and P concentrations have increased markedly at all sites, particularly during the past decade. Although additional research is needed to determine the potential of dendrochemistry in evaluating the consequences of environmental pollution, the age- and site-related trends in chemical composition of xylem wood of white pine and sugar maple appear to be related to vehicular emissions (Pb), air pollution (S), migration along ray paths during conversion of sapwood into heartwood (P, Fe, Ca, K, Mg), and possibly reallocation of nutrients from the labile soil pool to perennial tree tissues during stand development (Ca, K, Mg).
Effects of photoperiod and moisture availability on shoot growth, seedling morphology, and cuticle and epicuticular wax features of container-grown western hemlock seedlings
Authors: O'Reilly Conor , Arnott J. T. , Owens John N.
Published: February 2008

The influence of short-day and long-day photoperiods, and moderate drought stress (−1.0 MPa), all applied for 4 weeks beginning in mid-July, 1986, was studied on greenhouse-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings cultured in two Styroblock container cavity sizes. Shoot growth, morphology, and cuticle and epicuticular wax features were investigated. Weekly measurements of shoot growth were made from early June until growth cessation in October. Root collar diameter, shoot length, numbers of branches and needles, and needle lengths were recorded after shoot growth cessation in another subsample of trees. Shoot growth rapidly ceased under short days, whereas free growth continued under long days. Moisture stress had no effect on shoot growth phenology but significantly reduced final values for all morphological variables. The trends were similar in seedlings from both container sizes, but values were greater in those from the larger containers. Long days increased the total number of leaves and branches, especially under no moisture stress conditions. Under long days, stem unit and needle lengths were increased in the proximal portion of the shoot, whereas moisture stress alone reduced these values in the distal section of the shoot. Dormancy induction treatments had little effect on needle cuticle and epicuticular wax features, although fusion of wax rodlets in the stomata was less common under moisture stress conditions.
Phosphorus-fixing potential of Ah and H horizons subjected to acidification
Authors: Paré D. , Bernier B.
Published: February 2008

Invitro experiments on acidification of Ah and H horizons of soils originating from sugar maple (Acersaccharum Marsh.) stands in the Quebec Appalachians revealed that the amount of phosphate released to water by H horizons was not limited by acidification, while the phosphorus-fixing capacity of Ah horizons in the presence of added soluble phosphate increased linearly with increasing acidity. This experiment demonstrates the ability of soils with a moderately acid mull humus to limit the available phosphorus pool under acidification of the soil solution.