bluuebunny/crossref_metadata_2025 huggingface dataset:
Pollen contamination in a maritime pine polycross seed orchard and certification of improved seeds using chloroplast microsatellites
Authors: Plomion C , LeProvost G , Pot D , Vendramin G , Gerber S , Decroocq S , Brach J , Raffin A , Pastuszka P
Published: April 2011

A new concept of seed orchard was developed by Institut National de la Recherche Agronomique for the maritime pine (Pinus pinaster Ait.) breeding program: the polycross seed orchard (PSO). The expected genetic gain of the PSO can only be reached if the fathers used in the pollen mix contribute equally to the next generation (i.e., to the base material of the PSO) and if pollen contamination from the surrounding stands is limited. Using chloroplast simple-sequence repeats (cpSSR), we showed that the chloroplast DNA was unipaternally inherited in maritime pine and verified that the chloroplast haplotype composition of the megagametophyte tissue corresponded to the chloroplast haplotype of the female parent. As a practical application, a statistical test based on cpSSR markers and simulation was established to verify the PSO origin of maritime pine seed lots. As a result of the cpSSR test, it was observed that (i) departure from even distribution of the fathers in the PSO was barely significant, (ii) the minimum pollen contamination rate in the PSO was 36%, and (iii) the contamination was not evenly distributed in the PSO. As a consequence, the expected genetic gain will range between 50 and 82% of what was initially foreseen.
A reanalysis of nutrient dynamics in coniferous coarse woody debris
Authors: Holub Scott M , Spears Julie DH , Lajtha Kate
Published: April 2011

We analyzed net N, P, K, Ca, and Mg fluxes from decaying coarse woody debris (CWD) by developing a "volume-adjusted method" and applying it to existing chronosequence studies of CWD in temperate coniferous forests. Unadjusted nutrient concentrations may overestimate the amount of a given nutrient remaining or accumulating in CWD, because mass loss, primarily as microbially respired CO2, occurs during decomposition. This overall mass loss tends to increase nutrient concentrations (e.g., µg N/g CWD) by decreasing the denominator and, therefore, can be misleading as an indicator of nutrient flux. Our volume-adjusted method corrects for mass loss, by assuming a constant volume as CWD decays. Using this method we determined that (i) Ca and K were lost from CWD as decay progressed; (ii) N and P increased or had no net change in amount; and (iii) Mg results were mixed. Several studies showed net gains of Mg and several showed net losses. We discuss the applicability and limitations of the volume adjusted method and propose the use of isotopic and conservative tracers as more accurate, but more difficult, methods of investigating CWD nutrient fluxes. We also discuss possible nutrient flux pathways into and out of CWD.
Economics of a nest-box program for the conservation of an endangered species: a reappraisal
Authors: Spring Daniel A , Bevers Michael , Kennedy John OS , Harley Dan
Published: April 2011

An optimization model is developed to identify timing and placement strategies for the installation of nest boxes and the harvesting of timber to meet joint timberwildlife objectives. Optimal management regimes are determined on the basis of their impacts on the local abundance of a threatened species and net present value (NPV) and are identified for a range of NPV levels to identify production possibility frontiers for abundance and NPV. We apply the model to a case study focusing on an area of commercially productive mountain ash (Eucalyptus regnans F. Muell.) forest in the Central Highlands region of Victoria, Australia. The species to be conserved is Leadbeater's possum (Gymnobelideus leadbeateri McCoy), which is locally limited by a scarcity of nesting hollows. The modeling is exploratory but indicates that nest boxes may offer a promising population recovery tool if consideration is taken of their placement and areal extent through time.
Benefitcost analysis of DNA marker-based selection in progenies ofPinus radiataseed orchard parents
Authors: Wilcox P L , Carson S D , Richardson T E , Ball R D , Horgan G P , Carter P
Published: April 2011

The financial viability of DNA marker-based within-family selection (MBS) compared with full-sib family forestry was evaluated for Pinus radiata Donn. ex D. Don. Two traits were investigated: wood density (WD) and diameter at breast height (DBH, 1.4 m). Assuming 20 biallelic loci of equal additive effect controlling trait variation in 15 unrelated top full-sib families of P. radiata, marginal costs of quantitative trait loci (QTL) detection and selection were estimated based on an average of slightly less than five loci per family. We assumed a program where 10 genotypes per family per year were deployed over a 5-year period, and each replicated 100 000 times via fascicle cuttings methods. Estimated marginal costs were NZ$32 and NZ$72 per 1000 plants for WD and DBH, respectively. Genotyping costs were the single largest component for both traits. Genetic gains were estimated by modifying predicted log volumes (DBH) or proportion of structural-grade timber (WD) with and without pruning. Estimated genetic gains ranged from 3.2 to 3.4%. Net present values (assuming a 9.5% discount rate) ranged from an average of NZ$51 to NZ$621/ha. Results showed that MBS for DBH was more profitable than for WD, despite markedly higher costs of QTL detection. All trait-silviculture combinations showed financial gains with internal rates of return of 9% or greater, even when estimated revenues were decreased 70% from forecast revenues. While this analysis is based on a large number of assumptions, it is robust and the results show that significant financial gains from MBS are possible even when selection is based upon DNA markers linked to a few loci each of relatively small effect.
Nonuniform random sampling: an alternative method of variance reductionfor forest surveys
Authors: Williams Micheal S
Published: April 2011

Areal sampling has been used extensively in forest inventories. Prior to the 1950s, areal sampling used fixed-area plots exclusively. The advent of variable radius plot (VRP) sampling provided a substantial improvement in efficiency, both in terms of reducing the variance of the estimator for attributes such as basal area and volume and in the amount of fieldwork required to collect samples. However, since the advent of VRP sampling, there have been few substantial improvements in the efficiency of areal sampling. The purpose of this paper is to illustrate how varying the distribution of sampling points to account for large scale spatial variation can further improve the efficiency of forest inventories. While this is not a new idea, the approach taken here attempts to present the material in such a way as to make it accessible to the broadest spectrum of inventory practitioners. The method, referred to as nonuniform random sampling, is developed using a small forest population where the attribute of primary interest is the total number of trees. A simulation study, drawing samples of 20 fixed-area plots, was performed to compare the new method with current practice. The standard deviation of the estimator of the number of trees was reduced by a factor of about 1.4, meaning that almost 40 sample plots would be needed to achieve equal variance of the estimator using plot locations that were uniformly distributed over the population. To illustrate the potential shortcomings of this approach, the performance of the estimator of the total basal area was studied concurrently. The standard deviation of this estimator actually increased by a factor of more than 2, meaning that fewer than five sample plots would have been needed if the plot locations had been located in accordance with a uniform distribution over the area. Thus, while this technique can substantially reduce the variance for a single or small set of spatially correlated attributes for which the inventory is designed, the estimators of other attributes can be seriously compromised.
Heartwood production in a 35-year-old black walnut progeny test
Authors: Woeste K E
Published: April 2011

A 35-year-old black walnut (Juglans nigra L.) progeny test was evaluated for growth and production of heartwood. The test trees, which were open-pollinated progeny of select females in seven states, were planted on a good-quality, uniform site in Wabash County, central Indiana, U.S.A. Increment cores were used to estimate the amount of heartwood at 1.3 m above ground level. There were significant differences among open-pollinated families (α = 0.10) for both area of heartwood and percent area of heartwood. Narrow-sense heritability estimates for these traits were moderate (0.40 and 0.27), indicating opportunity for gain from selection. Faster growing trees had more heartwood and a higher percentage of heartwood area in cross section. Genetic correlations indicated that the rate and amount of heartwood formation is closely related to diameter growth.
Prescribed Burning in an Aspen – Mixed Hardwood Forest
Authors: Perala Donald A.
Published: April 2011

The effects of prescribed burning and complete clearcutting on Populustremuloides and associated hardwoods and shrubs were compared for 8 years after commercial harvest of a 60-year-old P. tremuloides stand. Because of the lack of suitable burning weather, P. tremuloides suckers were 2 years old before the burn could be made. All suckers were killed by fire and new suckers were more numerous but less vigorous, probably because of heat damage to shallow sucker-producing roots, loss of nitrogen, and reduced root carbohydrate reserves. Although prescribed fire can effectively control residual hardwood overstories detrimental to P. tremuloides sucker growth and survival, the long term effect of fire on sucker growth is unknown. Fire can be used to prepare sites for P. tremuloides regeneration when other methods are unavailable or impractical. Burning should be done during the first dormant season following logging. Effort should be made to distribute slash uniformly to provide even burning conditions. Burning prescription guidelines are given.
Dissemination of Seeds of the Eastern Dwarf Mistletoe by Birds
Authors: Hudler George , Nicholls Thomas , French D. W. , Warner Gloria
Published: April 2011

Seeds of the eastern dwarf mistletoe (Arceuthobiumpusillum Peck) were found on gray jays (Perisoreuscanadensis) and a red squirrel (Tamiasciurushudsonicus) trapped in a black spruce (Piceamariana (Mill.) B.S.P.) infection center in the Fond du Lac State Forest, Carlton County, Minnesota, U.S.A. In some instances, seeds of A. pusillum were carried as far as 100 m by gray jays.
Structure of Subarctic Forests on Hummocky Permafrost Terrain in Northwestern Canada
Authors: Zoltai S. C.
Published: April 2011

Examination of 30 stands in subarctic woodlands showed that most were even-aged, having been established after fires. Most fires killed all trees in the stand, but in some instances some trees survived, indicating light fires. The rare occurrence of uneven-aged stands shows that fire is not necessary for the development of open spruce–lichen woodlands. Diameter growth is relatively rapid in the young, fire originated stands, but slows down after about 100 years. Continuous heaving of the ground by frost action under the trees causes them to lean. In young, fire-originated stands the trees generally grow upright, but most trees are leaning after the stands are over 100 years old.
The Effect of Rooting Volume on the Early Growth of Lodgepole Pine Seedlings
Authors: Endean F. , Carlson L. W.
Published: April 2011

Lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) seedlings were germinated and grown for 20 weeks in containers with volumes ranging from 10 to 524 cm3 (0.6 to 32.0 in.3). Containers for four of seven volumes were constructed in three different ratios of height:diameter (1:1,3:1, and 6:1), with the remaining three volumes at 3:1. Rooting volume had a pronounced effect on dry weight and shoot length between 8 and 20 weeks. Rooting intensity was inversely correlated with shoot dry weight and a restricting intensity of about 0.45 mg/cm3 is suggested. Configuration of the container had no effect on dry weight or shoot length.
Relative susceptibility of five pine species, 2 to 36 months of age, to infection by Cronartiumcomandrae
Authors: Bergdahl D. R. , French D. W.
Published: April 2011

Five species of pines (Pinuscontorta Dougl. var. latifolia Engelm., P. divaricata (Ait.) Dumont = P. banksiana Lamb., P. nigra Arn., P. ponderosa Laws., and P. sylvestris L.) from 2 to 36 months of age were inoculated with basidiospores of Cronartiumcomandrae Pk. in the greenhouse and field. For the youngest age class (2 months), combined results from greenhouse and field inoculations indicate that P. sylvestris (18.8% infected) was the least susceptible. The combined infection averages for P. divaricata, P. nigra, P. contorta var. latifolia, and P. ponderosa were 52.4, 58.7, 63.8, and 68.2% infection, respectively. One-year-old P. ponderosa seedlings had the highest percentage infection (27.5%). Except for one 3-year-old P. ponderosa seedling, the seedlings older than 1 year were not infected. Pycniospores occurred within 80 days on some of the seedlings of all pine species except P. nigra (86 days).
Dry matter production in 40-year-old Pinusbanksiana stands in Quebec
Authors: Doucet Rene , Berglund John V. , Farnsworth C. Eugene
Published: April 2011

Dry matter production data were obtained for jack pine (Pinusbanksiana Lamb.) stands growing at three density levels on two sites. Regression equations relating tree weight to diameter and height were calculated for stem wood, stem bark, branches, needles, cones, and total aboveground biomass, as well as for periodic net annual increment of these components. Different sets of equations were needed to evaluate biomass on each site, but density levels within sites could be grouped. Total net periodic annual weight increment was linearly related to foliage weight and basal area, but a levelling-off at higher densities was evident when basal area was replaced by stand density index or bole area equivalent as the measure of density.
Biomass of jack pine and mixed hardwood stands in northeastern New Brunswick
Authors: MacLean David A. , Wein Ross W.
Published: April 2011

Biomass accumulation in 12 jack pine and 11 mixed hardwood stands of fire origin ranging in age from 7 to 57 years is presented. Logarithmic equations relating aboveground tree, crown, and stem biomass to tree diameter at breast height are given for eight tree species.
Prediction of cold hardiness in Douglas fir seedlings by index of injury and conductivity methods
Authors: Driessche R. van den
Published: April 2011

Electrical conductivities of diffusate from stem segments of Douglas fir (Pseudotsugamenziesii (Mirb.) Franco) were measured after exposing segments to various freezing temperatures and after heat killing. These data were expressed as conductivity percentage (conductivity after freezing as a percentage of conductivity after heat killing) or as index of injury (It, equivalent to conductivity percentage corrected for conductivity of unfrozen sample). Conductivity percentage, meaned over six test temperatures, predicted the temperature lethal to subsamples of whole plants exposed to different freezing temperatures reasonably well (R2 = 0.77, SEE = ±3.3 °C). However, 'critical' values of It associated with the temperature lethal to 50% of whole plants (T50) could only be determined for the three lowest test temperatures, and they varied from 32 to 40. In a controlled-environment experiment, levels of hardiness predicted by mean conductivity percentage, which seemed the most promising method, did not fully agree with survival results obtained from whole plants after freezing tests.
Stand reduction of red pine by Gremmeniellaabietina
Authors: Dorworth Charles E.
Published: April 2011

Damage to red pine (Pinusresinosa Ait.) by the North American race of Gremmeniellaabietina (Lagerb.) Morelet occurs primarily within the first 10 years after plantation establishment when mortality of 50 to 100% is common. Damage in the residual stands occurs as reduction in bole diameter at 1.3 m, increase in effective plantation edge as a consequence of the infection-pocket mode of disease etiology with consequent decrease in natural pruning and increase in branch diameter, and reduction in stand uniformity in terms of stem distribution and stem size. Not only are quantity and quality of products reduced but disruption of stand uniformity sharply limits the management forester's scope of silvicultural options.
Sodium chloride effects on carbon dioxide exchange rates and other plant and soil variables of ponderosa pine
Authors: Bedunah D. , Trlica M. J.
Published: April 2011

The effects of winter-applied sodium chloride on different plant and soil variables of ponderosa pine (Pinusponderosa Laws) were studied. Potted [Formula: see text]-year-old pine seedlings were treated with sodium chloride foliar sprays and subjected to irrigation treatments at salt concentrations of 0, 3000, 6000, and 9000 mg/L. Sodium chloride irrigations significantly affected the amount of foliar injury, electrical conductivity of the soil, and soil and foliar sodium and chloride levels. All sodium chloride irrigation treatments caused severe foliar injury and almost total mortality during the experiment.Treatments with sodium chloride foliar spray and distilled water irrigations had little effect on soil pH or electrical conductivity, foliar levels of sodium and chloride, and leaf injury or net photosynthesis. However, when plants were grouped according to soil levels of sodium and chloride, it was obvious that those plants having the highest soil sodium and chloride concentrations also had significantly higher injury levels and lower net photosynthesis rates. Soil concentrations of both these ions were too low to cause a decrease in soil solute potential. However, one or both of the sodium or chloride ions could have interfered with nutrient balance, osmotic regulation, or caused some type of specific ion toxicity.
Fire-induced water repellency in forest soils of upper Michigan
Authors: Reeder Cheryl J. , Jurgensen M. F.
Published: April 2011

Soils on 53 burned sites in the upper peninsula of Michigan were examined for fire-induced water repellency. The development of water repellency was found to be fire related with over 40% of the burned soils showing at least some water-repellent properties. Most water-repellent layers occurred in the upper 5 cm of mineral soil and were related to burn intensity. Laboratory burning experiments with 10 hardwood and conifer litters showed that white pine, red pine, and quaking aspen litter produced water repellency in underlying mineral soil. Repellency was also found on unburned sites, particularly under aspen. Water-repellent soils were widely distributed, but their nonwettable properties generally decreased rapidly over time. Fire-induced water repellency does not appear to present a major long-term management problem on most soils in this region. However, on certain burned sites, water repellency may influence seedling survival and subsequent stand establishment.
Survival of Phellinusweirii in Douglas-fir stumps after logging
Authors: Hansen E. M.
Published: April 2011

Stumps and roots of trees harvested 20, 30, and 50 years ago were examined for survival of Phellinusweirii. Survival was compared among sites regenerated to Pseudotsugamenziesii (Douglas-fir) and Alnusrubra (red alder). Distinctive patterns of decay and the persistence of setal hyphae and zone lines after death of the fungus enabled documentation of survival time and of the retreat of P. weirii from roots. Phellinusweirii often died from a decay column without colonizing adjacent sound wood.Data from 1076 roots on 340 stumps were analyzed. After 50 years, the fungus survived in 26% of the stumps and in 11% of the roots sampled. Surface mycelium was present on 17% of the roots after 20 years, 15% after 30 years, and 1% after 50 years. The decrease in survival time was similar on sites presently occupied by red alder or by Douglas-fir. Survival was not correlated with stump diameter or degree of deterioration after 20 and 30 years. In the current stand, trees killed by P. weirii were found within 5 m of 45% of infected stumps after 50 years.
Laser activation of phytochrome-controlled germination in Pinusbanksiana
Authors: Campbell Robert A. , Durzan Donald J.
Published: April 2011

A 100 ms exposure from a 5 mW helium–neon laser was sufficient to potentiate fully phytochrome-controlled germination in Pinusbanksiana Lamb. The energy requirement for the brief, high-intensity light exposure was comparable to that for a much longer, low-intensity light exposure. As a result, the laser may be valuable in studies of the germination process and the primary mode of action of phytochrome.
Nutrient use by three geographic sources of eastern cottonwood
Authors: Blackmon B. G. , Baker James B. , Cooper D. T.
Published: April 2011

Three geographic sources (Louisiana, Mississippi, and southern Illinois) of 11-year-old eastern cottonwood (Populusdeltoides Bartr.) growing in Mississippi, U.S.A., were studied for differences in biomass and nutrient accumulation. The three sources produced about the same biomass (70–80 t/ha (1 short ton = 2000 lb. = 0.907 t; 1 long ton = 2240 lb. = 1.016 t)), but the Louisiana source contained significantly lower N contents in the stems and lower K contents in both the stems and the total tree. Trees originating in Louisiana produced 640 g of dry matter for each 1 g of N found in the tree, compared with 430 g per gram of N for the Illinois source. The Louisiana source produced 430 g of dry matter per gram of K whereas the Illinois source produced about 200 g of biomass per 1 g of K. Thus, the Louisiana source appears to be more efficient in N and K utilization. Data indicate that if this stand were harvested at age 11, the Illinois source would remove 118 kg of N and 284 kg of K per hectare from the site. The Louisiana source would remove only 73 kg of N and 127 kg of K per hectare.
Light and temperature induced sporocarp formation of Phellinusweirii
Authors: Li Ching Y.
Published: April 2011

Eight isolates of Phellinusweirii (Murr.) Gilb. (Poriaweirii (Murr.) Murr.), a serious pathogen of conifer roots in northwestern United States and southern British Columbia, formed sporocarps on malt agar after exposure to continuous near-ultraviolet light for 4 days at certain temperatures followed by incubation at normal laboratory temperature (22–24 °C) and lighting conditions (118 lx for 8–9 h). Isolates G7312 and T-55 formed sporocarps when cultures were placed in normal or inverted positions; other isolates produced sporocarps only in an inverted position. Effective light–temperature combinations varied among isolates. Of all isolates, only G7312 and T-55 were induced to form sporocarps by fluorescent white light.
Range-wide genetic variation of black spruce: discussion
Authors: Falkenhagen E. R.
Published: April 2011

not available
Influences of spacing on radial growth and percentage latewood of Douglas-fir, western hemlock, and western redcedar
Authors: Smith J. Harry G.
Published: April 2011

Growth in ring width and percentage latewood on a very good site is described for 21-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), 20-year-old western hemlock (Tsugaheterophylla (Raf.) Sarg.), and western redcedar (Thujaplicata Donn) planted at five spacings (0.91 to 4.57 m). Cores extracted at breast height are used to show the effects of spacing through growth rate and crown development, and of age through number of rings from pith for the years 1965 to 1976. Percentages of latewood measured by binocular microscope are compared with results obtainable by X-ray methods for analysis of ring widths and densities. Influences of spacing on wood quality are discussed. It is concluded that wide initial spacings increase ring width and decrease percentage latewood significantly, but the reduced costs and increased sizes at wide spacings provide more than adequate compensation for the moderate reduction in wood quality.
An enzyme-linked immunosorbent assay for the detection of apple mosaic virus in yellow birch
Authors: Hardcastle T. , Gotlieb A. R.
Published: April 2011

An enzyme-linked immunosorbent assay (ELISA) method was developed to detect apple mosaic virus (ApMV) in Betulaalleghaniensis Britton. Tests for virus using bark and bud tissues of dormant trees were successful. ApMV was also detectable in old leaf tissue in August and September, as well as in newly emerging leaf tissue forced in a greenhouse in March. Whole crude antiserum used to coat ELISA plates in tests with bud tissues was a reliable substitute for purified immunoglobulin without loss of sensitivity or specificity. An attempt was made to use ELISA for quantifying virus concentrations in field samples of ApMV-infected birch leaves.
Clearcut harvesting and ectomycorrhizae: survival of activity on residual roots and influence on a bordering forest stand in western Montana
Authors: Harvey A. E. , Jurgensen M. F. , Larsen M. J.
Published: April 2011

Low numbers of active ectomycorrhizal roots persisted until July in forest stands that had been clearcut the preceding October. Two years after clearcutting, active ectomycorrhizal roots supported by an adjacent, uncut stand were found only 1.5 m into a clearcut, broadcast burned area. Effects of the clearcut burn reduced ectomycorrhizal activity for at least 7.6 m into the adjacent uncut stand. Taking advantage of the residual ectomycorrhizal mycelium in fall clearcuts requires that outplanting must be accomplished before July of the following season. Active fungal mycelium from roots of an adjacent stand will be of limited help to the rapid establishment of ectomycorrhizae on tree regeneration in broadcast burned clearcuts.
Photosynthesis and needle elongation response of Pinusstrobus clones to low level sulfur dioxide exposures
Authors: Eckert Robert T. , Houston Daniel B.
Published: April 2011

Sensitive and tolerant eastern white pine (Pinusstrobus L.) clones were exposed to 5.0 ± 0.5 pphm SO2 for 2 h. At the end of the fumigation, the average apparent photosynthetic rate was depressed by 27% in sensitive clones and by 10% in tolerant clones. Regression analysis of rate of reduction in photosynthesis over the 2 h was significant (0.05 level) for both classes, as was the difference (0.01 level) between the levels of the two regressions. Differences in final needle lengths of fumigated tolerant and sensitive clones were not significant.
Chronological sequence of element concentrations in wood of Carya spp. in the southern Appalachian Mountains
Authors: Berish C. W. , Ragsdale H. L.
Published: April 2011

Tree-ring analyses of hickory (Carya spp.) from the long-term ecological research site, Coweeta Hydrologic Research Laboratory, revealed that concentrations (micrograms per gram) of lead, aluminum, and zinc are increasing, that concentrations of copper, cadmium, nickel, and manganese have remained generally constant since the 1880's, and that hickory annual radial growth increments are declining. Lead, aluminum, and zinc burdens (microgram per growth interval), unlike their respective concentrations, have remained generally constant during the 1900's. The interpretation of growth and burden data indicates that hickory trees at Coweeta are in a mature phase of their life cycle and that annual growth does not seem to be reduced by pollutants.
Heritability and genetic correlations for stem diameter and branch characteristics in white spruce
Authors: Merrill R. E. , Mohn C. A.
Published: April 2011

Heritabilities were calculated for several traits in a selected population of 20-year-old Piceaglauca (Moench) Voss. The population had been modified by selection for rapid height growth at ages 12 and 18 years. Heritability estimates were moderate for branch angle and low for stem diameter, branch diameter, and number of branches per whorl. The genetic correlations among the traits indicated a negative relationship between rapid growth and desirable branch characters, although the correlations were generally small. The use of a two-stage selection procedure, selecting initially for rapid growth and subsequently for desirable branching traits, appears feasible in this population.
Ecological genetics of Pinuscontorta in the Wasatch and Uinta Mountains of Utah
Authors: Rehfeldt G. E.
Published: April 2011

Genetic differentiation of 45 populations of Pinuscontorta primarily from the Wasatch and Uinta Mountains was studied in field, greenhouse, and laboratory tests. Analyses of variables reflecting growth potential, morphology, cold hardiness, and periodicity of shoot elongation revealed population differentiation for a variety of traits. Regression models related as much as 77% of the variance among population means to the elevation and geographic location of the seed source. For genetic variation to be arranged along relatively steep environmental clines implies pronounced adaptive differentiation. As a result, seed transfer in reforestation should be restricted severely if maladaptation is to be controlled.
Biomass and nitrogen dynamics of hybrid poplar on two different soils: implications for fertilization strategy
Authors: Hansen Edward A. , McLaughlin Richard A. , Pope Phillip E.
Published: April 2011

One concern of short-rotation intensively cultured hardwood plantations is the accelerated loss of nutrients due to removal of large amounts of biomass and short harvest cycles. In this study, we examine simultaneously the nitrogen trends in all the various pools (trees, weeds, soil, and soil water). We compare the N trends and fertilization rates with leaf N status and tree growth on two soil types over 5 years. The data show a gradual transition from an early herbaceous plant dominated system to a tree-dominated system later in the rotation. On the more fertile site, fertilization was not beneficial to tree growth the 1st year, or even the 2nd, if all weeds were kept out. However, when weeds were present, fertilization was very beneficial to tree growth in the 2nd and 3rd years. After crown closure, fertilization declined in importance as herbaceous vegetation was eliminated, tree foliage biomass stabilized, and N cycling increased. Foliar N was strongly related to fertilizer rate during years 2 and 3 on the fertile site and during the entire 5 years on the infertile site. Form these relations and others, we infer possible critical times for N fertilization during the first 5 years of a rapidly growing hybrid poplar plantation from the time of initial planting through complete canopy closure and shading out of the herbaceous competition.
Stomatal conductance and growth of five Alnusglutinosa clones in response to controlled water stress
Authors: Hennessey T. C. , Lorenzi E. M. , McNew R. W.
Published: April 2011

An experiment to quantify the response of unnodulated, fertilized European black alder (Alnusglutinosa (L.) Gaertn.) seedlings to progressive water stress showed contrasting drought tolerance among five clones, using stomatal conductance, leaf area, and height as indices of drought sensitivity. In particular, one rapidly growing clone (AG 8022-14) showed the ability to moderate changes in water stress more efficiently than the more slowly growing clones. After 30 days of moderate levels of water stress, clones that had higher stomatal conductance also had greater leaf area and height growth. Leaf area and height were both sensitive to plant water status, although no threshold of stress associated with a cessation of leaf area or height expansion was found even though stomatal conductance decreased to 0.05 cm s−1 under severe water stress.
Shoot phenology and water relations of Piceaglauca
Authors: Grossnickle Steven C.
Published: April 2011

Piceaglauca var. albertiana (S. Brown) Sarg. shoot phenology and water relation parameters were monitored monthly for 1 year. Seedlings were kept outdoors, well watered, and exposed to seasonal changes in temperature and day length. Changes in shoot water relation parameters corresponded with changes in phenology. During spring, shoot elongation, osmotic potential at saturation, and turgor loss point were least negative, −1.30 and −1.56 MPa, respectively, whereas bulk modulus of elasticity at full turgor was at its highest, 22 MPa. Both osmotic potential at saturation and turgor loss point were most negative, −2.01 and −2.73 MPa, respectively, during late winter just before bud break. Shoot dry weight fraction was at its lowest, 0.33 g dry wt./g shoot weight and maximum symplastic water per unit weight of shoot tissue was at its highest, 3.99 g H2O/g dry wt., during spring shoot elongation. Number of osmoles of solute per kilogram shoot dry weight was highest during spring and late summer shoot elongation phases, 1.03 and 0.91 osmol/kg dry wt., respectively. These data suggest that P. glauca seedlings do not adjust well to dry site conditions.
Production of clonal plantlets of tropical pine in tissue culture via axillary shoot activation
Authors: Baxter R. , Brown S. N. , England N. F. , Ludlow C. H. M. , Taylor S. L. , Womack R. W.
Published: April 2011

A method for the production of multiple clonal plantlets of Pinuscaribaea var. hondurensis Morlet, P. oocarpa Schiede, and P. tecunumanii Equiluz and Perry (P. patula Schiede and Deppe ssp. tecunumanii (Equiluz and Perry) Styles) from juvenile sources is described. The procedure is based on the spontaneous production of axillary shoots following shoot elongation. Much interclonal variation exists with respect to expiant multiplication. The addition of activated charcoal (0.1%) stimulates shoot elongation, especially in recalcitrant clones of P. caribaea. Axillary bud initiation may be stimulated by 6-benzylaminopurine, but levels above 1 μM can result in failure of induced buds to form shoots. Rooting occurs at about 50% in nonsterile peat–perlite medium without auxin pretreatment. Rooted plantlets can be readily hardened and will grow normally in the glasshouse.
Characterisation of a fall protein of sugar pine and detection of its homologue associated with frost hardiness of western white pine needles
Authors: Ekramoddoullah Abul K.M. , Taylor Doug , Hawkins Barbara J.
Published: April 2011

A 19-kDa protein of sugar pine (named Pinl I; i.e., protein I of Pinuslambertiana Dougl.) was detected in increasing amounts in the fall. This protein was separated by SDS–PAGE and also by two-dimensional gel electrophoresis. Pinl I was composed of two acidic isoforms. This protein was subjected to N-terminal amino acid sequence analysis. The two isoforms had an identical N-terminal amino acid sequence. The N-terminal peptide was synthesized and purified, and the purity of the synthetic peptide was greater than 95%. The peptide was conjugated to a carrier protein, keyhole limpet hemocyanin (KLH). Rabbits were immunized with peptide–KLH and the antipeptide antibody was purified from the crude antisera by immunoaffinity chromatography. The antibody was shown to bind specifically to PinI I. This anti-Pin I I antibody was used in a Western immunoblot to detect the homologues of Pin1 1 in two other five-needled pines: western white pine (Pinusmonticola Dougl.; named Pinm III) and eastern white pine (Pinusstrobus L.). The antibody was also used to monitor the seasonal variation of Pinm III in western white pine needles. Pinm III was shown to be associated with overwintering of western white pine seedlings. A significant correlation was observed between the frost hardiness of western white pine foliage and the content of Pinm III.
Photosynthesis of black spruce, jack pine, and trembling aspen after artificially induced frost during the growing season
Authors: Lamontagne Manuel , Margolis Hank , Bigras Francine
Published: April 2011

Light-saturated photosynthesis following artificial frosts was monitored for black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), and trembling aspen (Populus tremuloides Michx.). None of the species exposed to -9°C in May or to -6 and -9°C in August recovered within the 23- and 14-day monitoring periods, respectively. Black spruce and jack pine treated at -6°C in May recovered within 5 and 23 days, respectively. Black spruce treated at -3°C in August recovered within 10 days. Frosts were applied to the upper and lower canopies of mature black spruce and jack pine in June and to mature trembling aspen in July. For black spruce, the lower canopy did not recover whereas the upper canopy partially recovered over the 10-day monitoring period. For jack pine and trembling aspen, there were no differences in recovery between canopy levels. Jack pine treated at -5.5°C recovered within the 10-day monitoring period whereas at -8.5°C, it only partially recovered. Although recovery period varied with species, phenological state, and frost temperature, gradual recovery of photosynthesis over 5-21 days seems a reasonable modelling algorithm for boreal tree species when growing season frosts lower than -3°C occur. However, cooling rates in our experiments were greater than those that normally occur in nature.
Relating land-use history and climate to the dendroecology of a 326-year-old Quercus prinus talus slope forest
Authors: Ruffner Charles M , Abrams Marc D
Published: April 2011

Dendroecology and land-use history were used to investigate the ecological history of a 326-year-old Quercus prinus L. forest. Quercus prinus, Castanea dentata (Marsh.) Borkh., and Pinus rigida Mill. dominated this talus slope prior to European settlement based on witness tree records. Oak species have exhibited continuous recruitment over three centuries probably in response to periodic fire and wind disturbances. While the stand escaped the direct impacts of timber cutting and the charcoal iron industry, the indirect effects of these land-use practices increased growth and recruitment. Different criteria were used for understory versus overstory trees to improve our detection of growth releases. Overall, major disturbances occurred approximately every 40 and 31 years before and after European settlement, respectively. This century, old-growth Q. prinus experienced marked growth increases coupled with high recruitment following the introduction of the chestnut blight (Cryphonectria parasitica (Murr.) Barr.) to the stand in 1909. Tree growth was also highly correlated with temperature and Palmer drought severity indices between 1895 and 1995. Climatic fluctuations in the 1820s-1830s and 1920s reduced radial growth and recruitment resulting in stem exclusion stages following regeneration pulses. Relating land-use history and climatic data to the dendroecology of this forest improved our understanding of its historical development.
Correspondence between single-tree and multiple-tree plot genetic tests for production traits in Pinus sylvestris
Authors: Jansson Gunnar , Danell Öje , Stener Lars-Göran
Published: April 2011

Although single-tree plots are often used in genetic tests in tree breeding programmes, it has often been argued that multiple-tree plots can express actual production traits more accurately. Single-tree plots can only be used without objection in genetic tests if they mimic production in closed stands sufficiently well. To determine the degree of this correspondence, genetic correlations between results from single-tree plots and those from multiple-tree plots, expressed as volume per unit area, were estimated for three sets of Scots pine (Pinus sylvestris L.) data, using restricted maximum likelihood methodology with an expectation-maximization algorithm. The number of parents common to the single- and multiple-tree plots varied between 18 and 28 among the different data sets. At the time of measurement the trees were 10-30 years of age. Genetic correlations between height, height increment, diameter, and volume per tree, respectively, in single-tree plots and volume per unit area in multiple-tree plots were strong, with a mean value of approximately 0.8. The results indicate that the performance of single-tree plots corresponds well with production in multiple-tree plots. Comparisons that took the higher selection intensity and lower generation interval into account showed that selection based on height in single-tree plots seemed more efficient than selection based on volume per unit area in multiple-tree plots.
Height and foliar responses of white spruce and lodgepole pine seedlings to deep tillage of Gray Luvisols
Authors: Nadeau L B , Pluth D J , Blenis P V
Published: April 2011

Seedlings of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss) were grown for 8 years under five different levels of deep tillage. These were, in increasing order of disturbance: control, vibration ripping, deep plowing, deep plowing plus residue, and Marttiini plowing. Five-year growth curves of each tree were partitioned into three orthogonal components: mean, linear, and quadratic trends. Nitrogen and phosphorus concentrations and mass of the current-year needles were analyzed. Deep plowing plus residue significantly reduced pine heights relative to both vibration ripping and the control, whereas spruce heights were less in the control treatment than in the vibration-ripped treatment. Tillage treatments did not affect nitrogen or phosphorus concentrations of current-year pine or spruce needles. In pine, deep plowing plus residue treatment resulted in the lightest needles, and Marttiini plowing, deep plowing and control treatments resulted in the heaviest needles. In spruce, needle mass was lowest for the deep plowing plus residue treatment and similar among the other treatments. Vibration ripping of medium-textured, well to imperfectly drained Gray Luvisols may be recommended to increase spruce seedling height growth, but any of the deep-tillage treatments used cannot be recommended for pine.
Development of freezing tolerance in roots and shoots of Scots pine seedlings at nonfreezing temperatures
Authors: Ryyppö Aija , Repo Tapani , Vapaavuori Elina
Published: April 2011

The hardening of hydroponically cultured Scots pine (Pinus sylvestris L.) seedlings and their recovery after freezing was studied at the end of the second growing season (LD), after 3 weeks of short day treatment (SD), after a gradual decrease in temperature to 5°C over 4 weeks (H1), and after 4 weeks at 5°C (H2). Frost hardiness was determined by several methods and the recovery as survival of the seedlings. The highest frost hardiness was achieved in the distal parts of needles (-21 to -27°C) and in the proximal parts of needles (-18 to -25°C), followed by woody roots (-7 to -9°C), the 1-year-old and current stem (-8°C), and the fine roots (-5°C), all at the end of H2. Hardening of needles was induced by SD, but the stem and woody roots started to harden later, as a response to low temperature. As a result of frost treatment during LD and SD, potential plasma membrane roman H+-ATPase activity of roots decreased as electrolyte leakage increased and extracellular resistance decreased, but this relationship was lost during H1 and H2. The present study demonstrates the lack of hardening capacity in the fine roots of Scots pine seedlings at nonfreezing temperatures and the increased mortality of the young seedlings having frost damage on roots.
Nutrient status and growth of black spruce layers and planted seedlings in response to nutrient addition in the boreal forest of Quebec
Authors: Paquin Raynald , Margolis Hank A , Doucet René
Published: April 2011

The effect of nutrient addition (fertilization with N, P, and K at a rate of 448, 224, and 224 kg ·ha-1, respectively) on height growth, root biomass, leaf area, and foliar nutrient concentrations of slow-growing layers and newly planted seedlings of black spruce (Picea mariana (Mill.) BSP) was evaluated on an apparently productive mesic site in Quebec. Annual height growth increment of fertilized layers was greater than 20 cm ·year-1compared with 3-4 cm ·year-1for the other three treatments. Fine root biomass (< 2 mm in diameter) and leaf area growth were significantly higher for fertilized layers and seedlings compared with their respective controls. For both current and 1-year-old needles, foliar N concentration on a unit leaf area basis increased significantly for both layers and seedlings, and vector analysis showed that, in all cases, N was the most limiting nutrient. Five growing seasons after treatment, the only residual effect of fertilization on foliar nutrient concentrations was higher foliar N in fertilized seedlings. Thus, it appears that the slow growth of the unfertilized layers on this site was due to resource limitation rather than to the type of regeneration as such.
Growth and morphological responses of yellow birch, sugar maple, and beech seedlings growing under a natural light gradient
Authors: Beaudet Marilou , Messier Christian
Published: April 2011

Height and lateral growth, biomass distribution, leaf morphology, and crown architecture were studied in yellow birch (Betula alleghaniensis Britton), sugar maple (Acer saccharum Marsh.), and beech (Fagus grandifolia Ehrh.) seedlings growing under 1-50% of above-canopy light in a sugar maple stand, in Quebec. All three species showed increasing growth with increasing light, but growth of yellow birch was higher and more responsive than that of sugar maple and beech. All three species showed typical sun-shade morphological responses, such as decreasing specific leaf area and leaf area ratio, and increasing leaf area index, with increasing light availability. Sugar maple was morphologically more plastic than the other species. It showed variations in biomass allocation to leaves and branches, a decrease in branch length to seedling height ratio, and a marked increase in the ratio of leaf area to stem length. Although our results clearly demonstrate the ability of these three species to modify several of their morphological features in response to variations in light, they do not show a clear relationship between species shade tolerance and morphological response to light variations. We suggest that species-specific developmental patterns may act as important constraints to morphological acclimation to light variation.
Factors affecting seed and cone development in Pacific silver fir (Abies amabilis)
Authors: Owens John N , Morris Sheila J
Published: April 2011

The reproductive development from pollination until seed maturity for Pacific silver fir (amabilis fir; Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes) was studied at two sites in British Columbia. Ten trees growing at varying elevations at each site were flagged and two or more cones were collected from each tree every 1 or 2 weeks. Following size measurements, cones were dissected and 20 ovules from each cone were sampled, fixed, embedded in paraffin, sectioned, and stained for anatomical study. Ovule, megagametophyte, and embryo size was measured and stage of ovule or seed and embryo was determined. At both sites the phenology and details of development were similar. The major causes of cone loss were frost at pollination and insect damage following pollination. The seed potential per cone was 359-408, but the filled seeds per cone based on cutting tests and X-raying was only 18-22%. The major causes of seed loss were insect damage (32-39%) during ovule and seed development and failure of ovules to be pollinated (26-31%). Although the amount of insect damage was similar at both sites, damage at Site 1 was primarily caused by Megastigmus sp. larvae in the seeds whereas at Site 2, damage was to seeds, scales, and the cone axis and due to Earomyia abietum larvae. Megagametophyte and embryo development is described and the time and causes of the seed loss are related to development. Anomalous types of development are described and possible causes discussed.