bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of interior spruce seedlings treated with abscisic acid analogs
Authors: Grossnickle Steven C. , Folk Raymund S. , Abrams Suzanne R. , Dunstan David I. , Rose Patricia A.
Published: May 2008

This research examined the performance of interior spruce (Piceaglauca (Moench) Voss × Piceaengelmannii Parry ex Engelm.) seedlings, each group treated with one of nine abscisic acid (ABA) analogs, during the initial stages of seedling establishment under a range of environmental conditions. Interior spruce seedlings were removed from frozen storage, ABA analog treatments were immediately applied, and seedlings were tested under low root temperature or moderate drought cycle conditions. Alternatively, seedlings were removed from frozen storage and held until bud break had occurred before ABA analog treatments were applied. These seedlings were then tested under severe drought or optimum environmental conditions. ABA analog 1, followed by ABA analog 2, had the most consistent performance of the nine tested ABA analogs under all combinations of environmental test conditions. These ABA analogs reduced needle conductance for 7–9 days when seedlings were tested under low root temperature conditions with only a reduction in net photosynthesis on the first day of testing. During three successive moderate drought cycles, seedlings treated with ABA analogs 1 and 2 had partial stomatal closure, thereby increasing mean shoot water potential by around 50%. During a severe drought, ABA analog 1 caused partial stomatal closure, which allowed seedlings to maintain a mean shoot water potential of greater than −3.0 MPa and a positive net photosynthesis up to 8 days longer than control seedlings. Under optimum environmental conditions, ABA analogs 1 and 2 reduced needle conductance for up to 7 days, with net photosynthesis reduced for 1 day. Root growth was not adversely affected in seedlings treated with any of the ABA analogs prior to bud break. However, when seedlings were treated after bud break, all ABA analogs reduced growth of long roots (>4.0 cm) by approximately 60%. ABA analogs 1 and 2 delayed bud break by 4 days, when compared with control seedlings. Results are discussed in reference to the establishment process of spruce seedlings on reforestation sites.
Foliage–sapwood area relationships for Abiesbalsamea in central Maine, U.S.A.
Authors: Gilmore Daniel W. , Seymour Robert S. , Maguire Douglas A.
Published: May 2008

Studies of forest productivity commonly invoke the pipe-model theory, which implies that leaf area or leaf mass in the tree crown is proportional to cross-sectional xylem (sapwood) area below the crown, to estimate leaf area or leaf mass from cross-sectional sapwood area. Prior ecophysiological studies have suggested that models to predict projected leaf area (PLA) from sapwood area for Abiesbalsamea (L.) Mill, are valid across a broad geographical region in northeastern North America. However, no single study has explicitly tested the applicability of different model forms to predict PLA from sapwood area. The objectives of this study were to (1) test the consistency of leaf area/sapwood area ratios at the base of the live crown among four canopy positions, (2) select the best sapwood-based model out of several published model forms to predict projected leaf area, (3) explore the ability of nonsapwood-based models to predict projected leaf area, and (4) test the validity of a common model to predict projected leaf area for A. balsamea in central Maine, U.S.A. We detected no strong statistical differences in the leaf area/sapwood area ratio at the base of the live crown among the open-grown, codominant, intermediate, and suppressed canopy positions. Using a modified likelihood criterion to compare the ability of various model forms to predict PLA, we found that a log–linear model incorporating sapwood area at breast height (BH) and crown length (CL) performed the best, but a log–linear model with CL as the sole predictor variable also performed well. We concluded that a single logarithmically transformed model form using sapwood area at BH and CL to predict PLA is valid among canopy positions, but a single model to predict LA from sapwood area is not valid across a broad geographical region in northeastern North America.
Height growth of jack pine (Pinushanksiana) in relation to site types in boreal forests of Abitibi, Quebec
Authors: Béland Martin , Bergeron Yves
Published: May 2008

A combination of surface deposit and moisture regime class was used to investigate the utility of site type as a predictor of jack pine growth in northwestern Quebec. Height–age curves produced from stem analyses of dominant trees from 96 sample plots produced three jack pine (Pinusbanksiaina Lamb.) productivity classes. The low productivity class includes moderately dry shallow tills, shallow organic deposits over bedrock, and fluvioglacial sands with moisture regime classes moderately dry and fresh. Moderately dry to very moist deep tills and moderately dry to moist clays are classified as having high and very high productivity, respectively. The large difference in height growth between these latter two groups and the low productivity class precluded the definition of a moderate productivity class. The form of the height-growth curves was very similar among site types except for sandy, moderately dry sites, which showed a growth delay at young ages. On dry sites, particularly on well-drained tills, density and basal area were higher than on clay sites. Although volume yield of natural stands on tills and clays would thus be similar, it would likely be spread among a greater number of stems on tills. There was little difference in site index between natural jack pine growing on clays and tills. The low nutrient and moisture requirements and strong taproot of jack pine could explain why soil depth and bulk density are more important than soil richness. Although site type, expressed as a combination of surface deposit and moisture regime class, may be more detailed than needed, it provided an adequate prediction of potential jack pine productivity.
A methodology for estimating production possibility frontiers for wildlife habitat and timber value at the landscape level
Authors: Arthaud Greg J. , Rose Dietmar W.
Published: May 2008

This paper presents a method for estimating production possibility frontiers when the objective is joint timber and wildlife habitat production. The developed method is a guided-search technique that iteratively changes stands to new harvest schedules based on the lowest marginal cost of habitat increases. To illustrate the technique, joint production of ruffed grouse (Bonasaumbellus) habitat and value from harvesting of aspen (Populustremuloides Michx. and Populusgrandidentata Michx.) stands is considered. A ruffed grouse habitat suitability model, with a focus on interspersion of four aspen age-classes, was used to evaluate habitat conditions. Aspen timber value was evaluated through use of growth and yield models in combination with discounted costs and revenues. The technique was implemented on a 261-ha land unit in Itasca County, Minnesota. The resulting production possibility frontier was estimated from analysis of only 2000 possible harvest schedule scenarios and was convex, indicating increasing marginal habitat costs. Habitat quality could be increased, to a maximum of 23%, at a cost of 25% of aspen timber value. Using 25 000 random harvest schedules, analysis of the underlying distribution of objective function values indicated that points on the estimated production possibility frontier consisted of values greatly exceeding the 99.99th percentile.
Deicing Salt (Sodium Chloride) Damage to Pinusresinosa Ait.
Authors: Sucoff Edward , Feller Ray , Kanten Dennis
Published: May 2008

Four studies demonstrated that NaCl spray was the primary cause of browning of Pinusresinosa Ait. along salted roads. All damaged needles had high Cl and when analyzed, high Na; the symptoms produced by spraying NaCl on forest trees appeared identical with highway symptoms; damage occurred in the spring warm-up after a winter buildup of Na and Cl; damage was greatest where use of deicing salts was greatest. Coincidence between Cl in needles and on needles indicated spray was the source of the salt. Brown needles had higher osmotic potentials (Ps) in proportion to NaCl content, but high Ps was probably incidental to damage. Still unexplained are the occasional green highway pines with high Na and Cl.
Resistance to Pulsed Electric Current: an Indicator of Stress in Forest Trees
Authors: Wargo Philip M. , Skutt H. Richard
Published: May 2008

Resistance to pulsed electric current was measured in stem tissues of white, chestnut, black, and red oak trees that had been defoliated by the gypsy moth, and their resistance was compared with that of undefoliated trees. Resistance to pulsed current was affected by tree species, diameter, crown class, and crown condition. However, regardless of species, diameter, crown class, or crown condition, defoliated trees had higher resistances than undefoliated trees. The relationship of resistance to pulsed current and tree vigor is discussed.
Nutrient Content of the Aboveground Tissue of 12-week-old Loblolly Pine Intraprovenance and Interprovenance Crosses
Authors: Woessner R. A. , Davey C. B. , Crabtree B. E. , Gregory J. D.
Published: May 2008

Nutrient content (P, K, Ca, Mg) of the aboveground tissue of a series of full-sib loblolly crosses was found to vary by genotype. Variability among and within seed sources is indicated for the ability to absorb Ca and Mg. Absorption of P and K was not found to be dependent on seed source, but the full-sib crosses differ. Good linear relationships were found between plant dry weight and weight of element but not between plant dry weight and percentage of element. Certain highly efficient crosses can be expected to be good producers of dry matter on sites low in available nutrients.
Wildfire Effects on Nutrient Distribution and Leaching in a Coniferous Ecosystem
Authors: Grier Charles C.
Published: May 2008

Distribution of nutrients after the Entiat fire in north central Washington was examined. This intense fire produced an average ash weight on the soil surface of 2900 kg/ha. The ash layer contained 23 kg/ha N, 314 kg/ha Ca, 54 kg/ha Mg, 70 kg/ha K, and 22 kg/ha Na. Nutrient losses during the fire as a result of combined volatilization and ash convection were 855 kg/ha N, 75 kg/ha Ca, 33 kg/ha Mg, 282 kg/ha K, and 698 kg/ha Na. Nitrogen loss apparently was proportional to fuel dry weight loss.Leaching of the ash layer in the 1st year after burning transferred a trace of N, 149 kg/ha Ca, 50 kg/ha Mg, 92 kg/ha K, and 33 kg/ha Na from the ash layer to the soil. Of the amounts leached from the ash, 134 kg/ha Ca, 48 kg/ha Mg, and 84 kg/ha K were retained in the 0-to 19-cm layer of soil. In the same interval a net loss of 29 kg/ha Na was observed from the 0-to 19-cm layer of soil.Cation leaching from ash layers was primarily related to water percolation through the ash. Equations are given that describe leaching of Ca, Mg, K, and Na from an average ash layer of the Entiat fire.
Nutrient–Growth Relationships in the Grand'Mère White Spruce Plantations before and after Fertilization
Authors: Phu Truong Dinh , Gagnon J. Daniel
Published: May 2008

Relationships were studied between the concentrations of N, P, K, and Mg in the needles and the growth of planted white spruce (Piceaglauca (Moench) Voss) on sandy marine and associated soils at Grand'Mère, Quebec. Multiple correlation analysis indicated a positive and highly significant relationship between K concentrations and growth expressed in terms of basal area and total volume. Foliar N was positively and significantly correlated with basal area and Mg with total volume. There was a negative relationship between P concentrations and both basal area and total volume. However, the coefficients of partial correlation for N, Mg, and P were low.Significant increases in increments of basal area and total volume were obtained with 50 and 100 kg/ha K, 5 and 10 years after application. There was a moderate response in total basal area to rates of 57.5 and 115 kg/ha N in the first 5 years only. No growth response was obtained with 45 kg/ha Mg for either period of observation. K, N, and Mg were applied as K2SO4, urea, and MgSO4 respectively. No significant residual effects of N or K on foliar levels of N, K, and Mg could be established 10 years after treatment, although a marked and significant residual effect of Mg on foliar Mg concentrations could still be detected in the fertilized plots. Thus, K appeared to be the main element that limited growth of white spruce in these plantations.
Analyse factorielle des relations entre le milieu et la production: étude des tremblaies de la section Laurentienne
Authors: Waksman Guy , Ménard Mario , Bélanger Jacques
Published: May 2008

The primary objective of this work is to study the relationships between ecological characteristics and forest production of the transition communities of trembling aspen (Populustremuloïdes Michx.) of the Laurentian section (L. 4a) defined by Rowe (1959). The study shows that factorial analysis of correspondences can be used to find ecological variables which influence the production level and for the study of the dynamics of communities.
Effect of Mechanical Stress on Growth and Anatomical Structure of Red Pine (Pinusresinosa Ait.): Torque Stress
Authors: Quirk J. Thomas , Smith Diana M. , Freese Frank
Published: May 2008

Torque is a vector component of wind acting on a growing tree. Mechanical devices which were attached to the tree were used to twist a single internode, which simulated the torque component in the absence of bending.Treatments either in a clockwise or counterclockwise direction were initiated at 20° and increased periodically through the entire growing season. Grain angle changed as much as 250% and radial growth was enhanced by as much as 100%, but fiber length decreased 20%.
Heart Rot of Jack Pine in Ontario. IV. Heartwood-inhabiting Fungi, Their Entry and Interactions within Living Trees
Authors: Basham J. T.
Published: May 2008

The five most common stem-inhabiting fungi of jack pine (Pinusbanksiana Lamb.) in Ontario were inoculated into the stems of living trees that were roughly 40 years old. Their natural occurrence in branch stubs and at various heights in the stems of these trees was also studied. From these results, and from those that were obtained from older trees in earlier studies, conclusions which concern the occurrence, importance, and apparent avenues of entry of these fungi are presented. Some of the trees were inoculated with one of the Ascomycetes, which was followed 1 year later by one of the Basidiomycetes. The interactions of the fungi in vivo did not always correspond with those observed in vitro; however, they do explain many of the observed relationships between the occurrence of these fungi in living jack pine and other factors. Fomespini (Brot. ex Fr.) Karst., the Basidiomycete that is responsible for most of the trunk rot of jack pine in Ontario, was not affected in living tree stems by the presence of the Ascomycetes that frequently colonize this tissue. On the other hand, Peniophorapseudo-pini Weres. and Gibson, the Basidiomycete that is responsible for about one quarter of the red trunk stain in this species, was almost completely inhibited in living trees by the presence of Ascocorynesarcoides (Jacq. ex Gray) Groves and Wilson, which would explain many of the unusual patterns of occurrence of P. pseudo-pini in living jack pine.
Mass Inoculation of Douglas-fir Seedling Roots with Phellinus (Poria) weirii (Murr.) Gilbertson
Authors: Wallis G. W. , Reynolds G.
Published: May 2008

A technique is described for the inoculation of roots of large numbers of seedlings in an undisturbed state, using stem wood of Douglas fir that was naturally infected by Phellinusweirii.
Estimators for successive forest sampling with partial replacement
Authors: Omule Stephen A. Y. , Kozak Antal
Published: May 2008

The coefficient of variation of forest stand volume can remain approximately constant over successive measurements. This consideration was exploited to provide an efficient estimator of the mean timber volume on the current occasion when sampling with partial replacement (SPR) on two occasions. For even-aged and normally distributed forest populations, the gains in precision were shown to be in the range of 8 to 200% when using the modified SPR estimator of the current mean volume.
Determining logging costs for long-term timber-supply projections: estimation of input requirements by phase of logging
Authors: Cooney T. M. , Haley D.
Published: May 2008

The problem of measuring the economic dimensions of a timber resource is discussed. It is suggested that for rational timber-supply analysis, a means of estimating economically recoverable timber stocks on a regional basis is required, plus an ability to forecast how these stocks will change over time in response to changes in technology, input costs, and timber prices. As a first step towards achieving these goals, a study is described which demonstrates that statistically significant relationships can be developed for predicting logging operability, using only those resource characteristics which are, or could be, included in inventory records. Using data collected for 48 logging operations in coastal British Columbia for the period 1977–1979, equations are estimated for predicting the length of roads required for harvesting an area, falling and bucking productivity, yarding productivity, scaled volume of logs harvested, and the probability of choosing a specific harvesting system. The use of these, or similar equations, for timber stock supply modelling is briefly described.
Nitrogen and organic-matter accumulation in coal mine spoils supporting red alder stands
Authors: Heilman Paul
Published: May 2008

Rates of nitrogen and organic-matter accumulation under red alder (Alnusrubra Bong.) stands were estimated by analyzing spoil materials at three abandoned open-pit coal-mine areas in western Washington. Average age of trees in natural stands at the three study areas varied from 10 to 30 years. Mean site indices (50 years) varied from 27 to 30 m. Mean pH of spoil surface samples varied from 4.0 to 4.6 which was less than for adjacent alder stands on natural soils but similar to values reported for alder stands in western Oregon. The increase in organic matter concentration in the surface 18 cm ranged from 0.96% under the 10-year-old stand to 2.94% under the 30-year-old stand. This represented an average increase of about 0.09% per year for all three stands with no significant differences among stands. The mean increase in nitrogen concentration ranged from 0.04 to 0.14% for the 10- and 30-year-old stands, respectively. This corresponded to an annual increase of 0.004% N with no significant difference among areas. Average rate of N accumulation in spoils varied from 59 to 65 kg N/ha•year−1. Differences between areas were not significant.
Early patterns of flowering, winter injury, and flushing of red maple progenies grown in five locations
Authors: Townsend A. M. , Wright J. W. , Beineke W. F. , Guries R. P. , Mohn C. A.
Published: May 2008

Red maple (Acerrubrum L.) seedlings grown from seed collected from throughout the species' natural range were planted in five states: Ohio, Michigan, Indiana, Wisconsin, and Minnesota. Flowering was almost exclusively dioecious and commenced in certain precocious progenies in the Ohio plantation 3 years after seed germination. Significant differences were found in all plantations among 7- and 8-year-old progenies in percentage of trees with flowers. Three plantations had differences in the number of flower buds per flowering tree and percentage of trees with winter injury. Variation among seedlots was apparent for length of the terminal leader injured by cold at two sites and for earliness of flushing in all plantations where recorded. Frequency of winter injury and time of budbreak of progenies showed a close relationship to geographic and climatic variables of seed sources, with northernmost progenies being less frequently injured and beginning growth first. There was also consistent progeny response between plantations in these two traits. Progeny from high elevations in the central and southern regions had less winter injury than progeny from low elevations. Flushing occurred in the seed lot sequence of northernmost origin first, southern next, and midlatitude last. Correlations of flowering frequency of progenies common to several plantations were in many cases significant, but correlations between plantations for numbers of flowers (per flowering tree) were less often significant.
Relationship between spacing and nitrogen fertilization of seedlings in the nursery, seedling size, and outplanting performance
Authors: Driessche R. van den
Published: May 2008

Nursery sowings of coastal and interior varieties of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), Sitka spruce (Piceasitchensis (Bong) Carr), and lodgepole pine (Pinuscontorta Dougl.) were thinned to different spacings 5 weeks after germination. Spacings in the drills, which were 15 cm apart, were 1, 2, 4, 8, and 12 cm, with the nursery sowing rate (about 0.6-cm spacing) as control. Spacings were applied factorially with three levels of N fertilizer: 60, 140, and 235 kg N ha−1. Two-year-old seedlings were planted out at Campbell River (coastal Douglas-fir) and Port Alice (Sitka spruce), both on Vancouver Island, and at Lyne Creek (interior Douglas-fir) in the Cariboo region and at Fulton Lake (lodgepole pine) in the Prince Rupert region of British Columbia. Wider spacing and greater N supply increased 2-0 seedling dry weight, root-collar diameter, and shoot height and also affected distribution of dry matter between needles, stems, and roots. Wider spacing increased survival of outplanted interior Douglas-fir by 12%. Survival of coastal Douglas-fir and Sitka spruce species was high and only increased 4 to 7% due to wide spacing after one season, but after three seasons wide spacing increased survival 17 – 19%. Compared with control, 12-cm spacing increased first-season shoot growth 53% for coastal Douglas-fir, 82% for interior Douglas-fir, and 71% for Sitka spruce. Second-season shoot growth of lodgepole pine was increased 92% by the widest spacing. Much of the improved growth was explained in terms of increased seedling size. At the highest level of N supply, increasing spacing to 4 cm did not greatly reduce yield of seedlings with root-collar diameters greater than 3 mm, except for interior Douglas-fir. Thus moderate increase in spacing improved quality without materially reducing yield of seedlings per unit area of nursery. Nursery fertilization at 235 kg N ha−1 increased new-shoot growth one season after planting by 36–58% compared with the 60 kg N ha−1 level. After three seasons the effect of higher N supply was reduced to 0–42%. High N level increased survival of coastal Douglas-fir and Sitka spruce slightly, but decreased survival of interior Douglas-fir.
Effects of dewinging, soaking, stratification, and growth regulators on germination of green ash seed
Authors: Tinus Richard W.
Published: May 2008

Dewinging stored seed of green ash (Fraxinuspennsylvanica Marsh.) increased speed of and total germination. Fresh seed germinated best with a 4-day warm-water soak followed by 30-day stratification at 3 °C. Best procedures for stored seed were a 4-day soak in 100 ppm giberellic acid or a 2-day soak in 1 – 10 ppm 6-benzyladenine, followed by 30-day stratification at 3 °C.
Measurement of water stress in subalpine trees: effects of temporary tissue storage methods and needle age
Authors: Kaufmann Merrill R. , Thor Gary L.
Published: May 2008

Water stress of subalpine conifer species may be measured with the pressure chamber after several hours of tissue storage. Tissue samples stored in cool, humid vials exhibited very little change in xylem pressure potential over a 4-h period. However, xylem pressure potential declined steadily when a source of water vapor was not available. Xylem pressure potentials of current-year and 1-year-old needles of lodgepole pine (Pinuscontorta var. latifolia Engelm.) were slightly lower than those of older needles.
Nodulation and nitrogen fixation by red alder and Sitka alder on coal mine spoils
Authors: Heilman Paul , Ekuan Gorden
Published: May 2008

Nodule number, nodule weight, and nitrogen fixation (nitrogenase activity by acetylene reduction) were determined for 3 years for red alder (Alnusrubra Bong.) and Sitka alder (Alnussinuata Reg. Rydb.) on three types of coal spoils in western Washington. Generally, the two species were similar in number and weight of nodules and in nitrogen-fixation rates when measured in June (these rates varied from 23 to 27 µmol•g−1•h−1). The type of coal spoil material influenced nodule number but not nodule weight. Topsoil covered subsoil had the highest number of nodules. Trees on unweathered subsoil had the lowest number, particularly for Sitka alder. Nodule weight (dry, ash free) varied from 68 kg•ha−1 for 5-year-old Sitka alder interplanted in a 1:1 mix with Douglas-fir (1790 alders•ha−1) to 188–200 kg•ha−1 for pure stands of both alder species at age 5 (5380 trees•ha−1). The difference in nodule weight between species was not significant. Both species fixed nitrogen at similar rates although in the last year of measurement red alder trees fixed 37% more nitrogen than Sitka alder. This difference was not significant, however. Nitrogen fixation per unit area depended on tree age and spacing, varying from 17 kg•ha−1•year−1 at age 3 with 1830 alders•ha−1 to 150 kg•ha−1•year−1 by both species at age 5 and a density of 5380 trees•ha−1. Fixation rates increased from age 3 to 5 years primarily because of increased nodule weight. Nitrogen fixation by the Sitka alder in mixture with Douglas-fir was relatively high and was encouraging for the concept of mixed plantings of these two species. However, response of Douglas-fir to mixed planting with Sitka alder has not been demonstrated.
Rate, timing, and mode of gibberellin application for female strobilus production by grafted loblolly pine
Authors: Greenwood Michael S.
Published: May 2008

Gibberellin A4, gibberellin A7, and their mixture (60:40, GA4:GA7) were approximately equally effective in promoting female strobilus production on 3-year-old grafted mature scions of loblolly pine (Pinustaeda L.). Gibberellin A3 was ineffective. The female flowering response to GA4/7 was proportional to the log of its concentration, but no significant effect on male flowering was observed. Topical application from June through September was the most effective mode of application. Application for shorter intervals during this period resulted in proportionately less flowering. GA was equally effective prior to and following female bud initiation, but most effective during both.
Hardiness and growth of western spruce species and hybrids in Ontario
Authors: Ying C. C. , Morgenstern E. K.
Published: May 2008

Forty-five provenances or progenies of Piceaglauca (Moench) Voss, P. sitchensis (Bong.) Carr., P. engelmannii Parry, and their various F1 and F2 hybrids and backcrosses were tested in two replicated and one unreplicated experiments at Chalk River, Ontario. At ages 10, 15, and 22 years from seed, large differences in survival, growth, and hardiness were found. Hardiness was closely correlated with the proportion of Piceaglauca germ plasm. Implications for the use of hybrids in silviculture are discussed.
Response of sweetgum to mycorrhizae, phosphorus, copper, zinc, and sewage sludge
Authors: Lambert D. H.
Published: May 2008

A recent study has suggested that sweetgum (Liquidamberstyraciflua L.) differs from other species in that its marked response to mycorrhizae is not due to improved nutrient uptake. To investigate this possibility, sweetgum seedlings were grown in a 1:1:1 mix of peat, sand, and sandy loam treated factorially with: (i) 0, 50, or 500 ppm P; (ii) 0 or 5 ppm Cu; (iii) 0 or 8 ppm Zn, and (iv) Glomusfasciculatus Gerdemann and Trappe or no mycorrhizal inoculum. After 5 months' growth in the greenhouse, nonmycorrhizal seedlings receiving 500 ppm P were growing at the same rate as P-fertilized mycorrhizal seedlings and foliar P concentrations were higher in the mycorrhizal treatments. Mycorrhizae also alleviated a minor copper deficiency which occurred at the high level of P in the nonmycorrhizal treatments. The benefit of mycorrhizae to sweetgum is therefore a typical nutrient response, which may have been overlooked in previous work with this species by use of too narrow a range of phosphorus levels.
Chemical composition of forest fuels affecting their thermal behavior
Authors: Rogers Janice M. , Susott Ronald A. , Kelsey Rick G.
Published: May 2008

Flaming combustion is dependent upon the production of flammable volatiles that originate from the heating of the fuel materials. The thermal reactions that take place during this heating are determined by the chemical composition of the fuel. A knowledge of fuel chemistry and thermal reactivity can be useful in understanding and predicting fire behavior. Four plant materials were studied because their thermal decomposition curves showed unusually strong peaks from unknown combustible volatiles. The objective was to isolate and identify the chemical source of these volatiles. The tissues were methodically fractionated by following previously published techniques. Effects of each fractionation were carefully monitored by thermogravimetric analysis before and after treatment. Arabinogalactan was identified as the source of 325–350 °C volatiles from western larch (Larixoccidentalis Nutt.) wood. The major component of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) bark that decomposed above 400 °C was suberin. Foliage from gallberry (Ilexglabra (L.) Gray) and ponderosa pine (Pinusponderosa Laws.) contained cutin, which was responsible for their volatiles produced above 400 °C. The thermal behaviors of suberin and cutin reflect their similar chemical composition. The presence of these chemical components may produce similar thermal behavior in numerous other plant tissues.
Distribution and cycling of macronutrients in a Pinusresinosa plantation fertilized with nitrogen and potassium
Authors: Bockheim J. G. , Leide J. E. , Tavella D. S.
Published: May 2008

Fertilization with 100 kg K ha−1 as KCl and 100 kg N ha−1 as NH4NO3 resulted in an 11% increase in aboveground biomass and a 32% increase in aboveground production 4 years following fertilization of a 33-year-old red pine (Pinusresinosa Ait.) plantation in central Wisconsin. The greatest absolute increase in dry matter occurred in the foliage, followed by the sapwood and the live branches. Fertilization increased all macronutrients (N, P, K, Ca, Mg) in the aboveground tissues. The increase was greatest for N, followed by Ca, K, Mg, and P. The net gains in macronutrients in the live branches and the sapwood were due not only to increases in dry matter production but also to increases in nutrient concentrations. However, the increases in macronutrients in the foliage were related to an increase in foliage mass rather than to changes in foliar concentrations. Whereas 26 kg K ha−1 (26% of applied K) was recovered in the biomass and forest floor 4 years after fertilization, 107 kg N ha−1 (107% of applied N) was recovered in these pools. The greater recovery of N than the amount applied was attributed to additive errors associated with preparation of nutrient budgets. Fertilization increased leaching losses of all macronutrients, especially [Formula: see text] and Ca2+, at the bottom of the rooting zone. However, leaching losses returned to levels measured in the control stand within 5 [Formula: see text] to 14 months [Formula: see text] following fertilization.
White ash seedling growth response to ozone and simulated acid rain
Authors: Chappelka III A. H. , Chevone B. I.
Published: May 2008

Five-week-old white ash (Fraxinusamericana L.) were exposed to O3 (0.00, 0.05, 0.10, or 0.15 ppm, 4 h/d, 5 d/week) in combination with simulated rain (pH 3.0, 4.3, or 5.6, 1 h/d, 2 d/week, at 0.75 cm/h) for 5 weeks, under controlled environmental conditions, with rain applied either just before or after fumigation. Across all other treatments, increasing concentrations of O3 resulted in significant linear decreases in root, leaf, and total dry weights, total height increase, root/shoot ratio, and mean relative growth rates of the total plant, stem, root and leaves ([Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively). Significant linear decreases in root dry weight, [Formula: see text], and root/shoot ratio occurred with increasing rain acidity. A significant quadratic response was observed with rain pH for all aboveground variables measured. Growth was the greatest for seedlings treated with pH 4.3 and the least for those treated with pH 5.6 or 3.0 simulated rain. The timing of rain application relative to O3 exposure did not significantly alter any growth variable. Visible symptoms of O3 (0.15 ppm), simulated rain (pH 3.0), or O3 plus simulated rain (0.15 ppm and pH 3.0) were observed on 61, 61, and 54% of the seedlings in each treatment, respectively. The combined effect of O3 and simulated rain resulted in significantly less root dry weight, [Formula: see text], and root/shoot ratio at 0.05 ppm O3 and significantly less [Formula: see text] and root/shoot ratio at 0.10 ppm O3 as rain pH decreased. These findings are discussed relative to the implications of O3 and acidic precipitation on white ash growth.
Electrophoretic and morphological differentiation of Piceasitchensis, Piceaglauca, and their hybrids
Authors: Yeh Francis C. , Arnott J. T.
Published: May 2008

Isozymes and seedling morphology were used to differentiate among nine reforestation seed lots that included three Piceasitchensis (Bong.) Carr., two Piceaglauca (Moench) Voss, and four putative hybrid spruces from the coast–interior zone of reported introgression in British Columbia. Among 18 isozymes, 6 (Adh, Dia-2, Gdh, G6p, 6pg-1, and 6pg-3,) were most useful in separating P. sitchensis and P. glauca. 6pg-1 was the best single criterion to differentiate among the seed lots. Among 10 morphological characteristics, 5 (pattern of terminal bud set when photoperiod was reduced to 15 h, to 14 h 10 min, and to 13 h 25 min, shoot length at end of growing season, and degree of needle serration) were highly variable among seed lots. Pattern of terminal bud set when photoperiod was reduced to 14 h 10 min and degree of needle serration were the two best morphological criteria for seed lot differentiation. Electrophoretic and morphological data were in complete agreement with respect to species classification for the nine seed lots. Such results suggested that isozymes would be useful for taxonomic classification of spruce seed lots collected in areas where introgressive hybridization of P. sitchensis and P. glauca has been reported.
Fertilizer stimulates growth and mortality in a young Populus–Betula stand: 10-year results
Authors: Safford L. O. , Czapowskyj M. M.
Published: May 2008

Following a uniform thinning, a young bigtooth aspen (Populusgrandidentata Michx.), quaking aspen (Populustremuloides Michx.), paper birch (Betulapapyrifera Marsh.), and red maple (Acerrubrum L.) stand was treated with nitrogen (N), phosphorus (P), and lime, singly and combined. Nitrogen increased the growth of all species. Lime and P also tended to increase the growth of bigtooth aspen and paper birch. Nitrogen increased mortality and lime reduced mortality. Quaking aspen suffered proportionally greater mortality than other species. The results suggest that both N and lime will be required for an optimum response of aspen and birch growing on acid spodosols in the Northeast, but the cause of and a means to avoid increased mortality caused by fertilizer needs to be determined before large-scale N fertilizer treatments are adopted.
Stomatal and photosynthetic response of drought-stressed cherrybark oak (Quercusfalcata var. pagodaefolia) and sweet gum (Liquidambarstyraciflua)
Authors: Pezeshki S. R. , Chambers J. L.
Published: May 2008

The effects of water stress on stomatal conductance and net photosynthesis of cherrybark oak (Quercusfalcata var. pagodaefolia Ell.) and sweet gum (Liquidamberstyraciflua L.) seedlings were studied under controlled environment conditions during the 1983 growing season. Drought stress induced stomatal closure and significant declines in net photosynthesis for both species. Stomatal conductance declined by as much as 43% in cherrybark oak and 82% in sweet gum compared with predrought levels. Net photosynthetic rates also declined 85% from predrought levels in sweet gum and fell below zero in cherrybark oak. The remarkable decline in net photosynthesis in cherrybark oak while stomata remained partially open suggests that in addition to a stomatal effect, nonstomatal factors were involved in the reduction of net photosynthesis. In sweet gum, however, stomatal limitation of net photosynthesis seems to be the dominant factor. The greater relative decline in mean leaf conductance in sweet gum suggests a greater reaction to drought by this species through effective and rapid stomatal closure resulting in avoidance of leaf desiccation. Stomata of cherrybark oak, on the other hand, were less sensitive to low leaf water potentials; therefore, stomatal closure occurred at significantly lower (more negative) leaf water potentials when compared with sweet gum.
Growth and production of leaf litter nitrogen by Alnusincana in response to liming and fertilization on degenerated forest soil
Authors: Huss-Danell Kerstin
Published: May 2008

Degenerated and nonproductive forest soils having a very low content of nitrogen and organic material can probably be restored by cultivation of nitrogen-fixing plants such as Alnus spp. The effects of liming and N fertilization on enhancement of early growth and biomass production of Alnusincana (L.) Moench were studied in northern Sweden. Survival was over 90% in all treatments. During the 1st year, root growth was more rapid than shoot growth, reflecting acclimation of the nursery grown plants to the field conditions. In the following 5 years, the height increase and the production of leaf litter biomass and leaf litter nitrogen were significantly higher in limed than in unlimed alders. N–P–K fertilization also had a positive effect, while N alone had a negative effect. During the 6th year, limed alders, at a spacing of 1.5 × 1.5 m, produced 440–710 kg leaf litter ha−1 containing 11–17 kg Nha−1. Unlimed alders produced 50–250 kg leaf litter ha−1 containing 1–6 kg Nha−1. Therefore, the simple and inexpensive treatment of liming at planting considerably enhanced the growth and production of leaf litter nitrogen by A. incana at the site.
Heat tolerance of actively growing, bud-initiated, and dormant black spruce seedlings
Authors: Koppenaal R. S. , Colombo S. J.
Published: May 2008

To determine the effect of stage of bud development on heat tolerance, overwintered black spruce seedlings (Piceamariana (Mill.) B.S.P.) were (i) maintained in a dormant state, (ii) allowed to grow new shoots under favorable greenhouse conditions, or (iii) induced to initiate bud scales using short-photoperiod treatment following a period of new shoot elongation. Seedlings of the three shoot types were then exposed for 10 min to temperatures of 25, 42, 45, 50, or 55 °C in an environmental test chamber. Damage to the current-year shoot was lower in bud-initiated seedlings than in active seedlings, particularly at 42 °C, when 0 and 46%, respectively, of the length of the main shoot was damaged. The current-year shoot growth was much more sensitive to heat stress than the lignified first-year shoot, and therefore dormant seedlings, which had only first-year shoot growth, were most heat tolerant, showing damage only at 50 and 55 °C.
Height growth and survival of within- and between-provenance crosses in jack pine
Authors: Magnussen S. , Yeatman C. W.
Published: May 2008

Controlled pollinations with provenances from Petawawa (Ontario), Fife Lake (Michigan), and Big River (Saskatchewan) were made in all possible combinations, with the ensuing offspring planted at three sites along a north-south transect in Ontario. Survival at age 8 decreased with increased boreal character at the site. Survival of provenance hybrids was intermediate to that of their intraprovenance counterparts. Statistically significant heterosis (departure from midvalue of associated intraprovenance performances) was observed in tree height at two locations. At the northern-most site, growth was poor, with no significant differentiation among any of the tested full-sib families. Within-block microsite quality was unevenly distributed at two sites, which resulted in a low blocking efficiency and a highly significant among-plot variation. However, with five full-sib families per provenance cross, the impact on the statistical analysis of crosses was negligible.
Relations entre la microtopographie, les caractéristiques de la couverture morte et la répartition des essences dans une érablière à Bouleau jaune
Authors: Ruel Jean-Claude , Loustau Denis , Pineau Marius
Published: May 2008

Some effects of microtopography on forest floor, organic matter dynamics, and tree species distribution were studied in a northern hardwood stand near Québec. Forest floor thickness was 12.4 cm in pits while it was only 7.6 cm on mounds. These variations in thickness were attributed to a smaller litter accumulation (186 vs. 318 g m−2 year−1 in pits) and a more rapid decomposition on mounds (weight losses of wooden probes, 17.3 vs. 13.7% in pits). Over 43% of yellow birch stems (Betulaalleghaniensis Britton) were found on mounds in comparison with 20% for beech (Fagusgrandifolia Ehrh.). Sugar maple (Acersaccharum Marsh.) distribution was intermediate between those species. Thus, mounds seem more suitable for yellow birch installation, either because of their characteristics after their formation or because of the thinner forest floor formed on these microsites.
Growth and net assimilation rates in thinned and unthinned stands of balsam fir
Authors: Lavigne M. B.
Published: May 2008

Current annual stem growth rates per hectare of unthinned young stands of balsam fir (Abiesbalsamea (L.) Mill.) were 2–3 times greater than in adjacent stands thinned 4–6 years earlier, largely because unthinned stands contained 2.5–4.0 times more foliar weight per hectare. Stem growth rates per tree in thinned stands were 3–8 times greater than those in unthinned stands because of the reduced competition and the lower ratio of heterotrophic to autotrophic tissues (S/F). However, the foliar efficiencies, as measured by annual stem growth per unit of foliar weight (E), of thinned plots were not significantly greater than those of unthinned plots, in spite of the reduced competition and lower S/F ratio. The lack of response of foliar efficiency to thinning is discussed in relation to published information about photosynthetic rates and stem respiration rates. In all stands, the E values of dominant trees were equal to, or less than, those of subordinate trees, in spite of their superior competitive position and lower S/F ratio. The lack of correlation between competitive position and foliar efficiency is also discussed.
An ecophysiological basis for understanding plantation establishment
Authors: Margolis Hank A. , Brand David G.
Published: May 2008

Forest plantations in the early stages of establishment are considered as hierarchical biological systems, and some implications for the design of research projects and the education of regeneration foresters and scientists are discussed. Since less than optimum environmental conditions convey stress to seedlings, seedlings will in turn exhibit a strain response at either the biochemical, physiological, or morphological level. Environmental conditions in a clear-cut are contrasted with other regeneration niches, and implications for the performance of different plantation species are discussed. The important physiological and biochemical limitations on the absorption of water, nitrogen, and carbon by seedlings during their establishment phase are described. Methods of quantifying stress at the plantation site, including simple ways to separate seedling growth into its different physiological components, are shown. An example of an eastern white pine (Pinusstrobus L.) plantation grown under different levels of soil temperature, fertilization, and brush control is presented to illustrate the concepts. An approach to silvicultural research is proposed that determines the effects of silvicultural treatment on the seedling environment and then relates these environmental conditions to seedling biochemistry, physiology, and growth.
Growth and survival of shoots, roots, and mycorrhizal mycelium in clonal Sitka spruce during the first growing season after planting
Authors: Coutts M. P. , Nicoll B. C.
Published: May 2008

Rooted cuttings of three Sitka spruce (Piceasitchensis (Bong.) Carr.) clones were grown out of doors in 2 m tall acrylic tubes of peat that projected from the tops of insulated boxes. During the year, periodic measurements were made of temperature and the growth of shoot, root, and extramatrical mycelium of mycorrhizal fungi. Differences were found between clones in total shoot and root growth and in their periodicity, especially in the timing of the onset of root dormancy in the winter. No fine root death was observed during a 7-month period of observation. Most of the plants became colonized by mycorrhizal fungi, and fruiting bodies were produced in the tops of the tubes. Two of the clones were colonized by Thelephoraterrestris (Ehr.) Fr., but in a third clone some plants were colonized by T. terrestris and others by Laccariaproxima (Boud.) Pat. The extramatrical mycelium of T. terrestris grew at about half the rate of the main roots during the summer, and by November it had grown a mean distance of 22 to 25 cm, depending upon the tree clone colonized. The mycelium grew slowly during the winter when the main roots were dormant. The L. proxima mycelium grew much more slowly than the T. terrestris, and it disappeared during the autumn.
A comparison of numerical methods for optimizing even aged stand management
Authors: Valsta Lauri T.
Published: May 2008

A two-species, whole-stand, deterministic growth model was combined with three optimization methods to derive management regimes for species composition, thinnings, and rotation age, with the objective of maximizing soil expectation value. The methods compared were discrete time – discrete state dynamic programming, direct search using the Hooke and Jeeves algorithm, and random search. Optimum solutions for each of the methods varied considerably, required unequal amounts of computational time, and were not equally stable. Dynamic programming located global optimal solutions but did not determine them accurately, owing to discretized state space. Direct search yielded the largest objective function values with comparable computational effort, although the likelihood of finding a global optimum solution was high only for smaller problems with up to two or three thinnings during the rotation. Random search solutions varied considerably with regard to growing stock level and species composition and did not define a consistent management guideline. In general, direct search and dynamic programming appeared to be superior to random search.