bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of harvest cycle and spacing on productivity of black cottonwood in intensive culture
Authors: Heilman Paul , Peabody Jr. D. V.
Published: July 2007

Results after 8 years at two experimental sites show no productivity advantage for very short rotations of black Cottonwood; in fact, harvest cycles less than 8 years reduced productivity. At one site, the combined yield from two harvests at 4-year intervals was only 75% of the yield from one harvest at 8 years. Mean annual dry biomass increment per hectare was 6.05 t for the former versus 8.05 t for the latter (P ≤ 0.001).At another, more productive site, annual dry biomass increment averaged 5.8 for the first 2-year harvest, 8.9 for the second 2-year harvest, and 9.7 t/ha for the third harvest made after 4 years (total age of the planting at time of the third harvest was 8 years). Productivities for the second and third harvests were significantly higher than for the first harvest (P ≤ 0.05) but were not significantly different from each other.Highest productivity over 8 years for 2- and 4-year harvest cycles was obtained with 30 × 30 to 61 × 122 cm spacings. Productivity from a single 8-year harvest cycle was also highest at 61 × 122 cm spacing. However, data from both studies indicated a declining effect of spacing on productivity with increasing age of the planting.
Physiological response of large Douglas-fir to natural and induced soil water deficits
Authors: Lassoie James P. , Salo David J.
Published: July 2007

The effect of soil water deficits on net photosynthesis, transpiration, stomatal activity, twig xylem pressure potentials, and cambial growth were studied in large, field-grown Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). Abnormally high soil and tree water deficits were periodically induced during the summer by withholding supplementary irrigation water from a 28-m Douglas-fir contained in a weighing lysimeter. This eventually promoted persistent stomatal closure which limited gas exchange rates. At such times, net photosynthesis was confined to early morning daylight hours and daily totals were reduced by about 70% compared with the well-watered condition; xylem pressure potentials decreased only about 0.6 MPa during the day from a predawn level of −1.6 MPa. After irrigation or major rainfall, predawn xylem pressure potentials increased to −0.4 MPa and the tree stem abruptly increased in size; both indicated the hydraulic recharge of internal tree tissues depleted during the induced drought. Stomata then responded primarily to light, even though midday xylem pressure potentials remained near −2.2 MPa. These data are compared with those obtained from a nearby tree which was responding to natural fluctuations in soil moisture content.
Accumulation of food reserves in cottonwood stems during dormancy induction
Authors: Nelson Eric A. , Dickson Richard E.
Published: July 2007

Early chemical storage as related to growth changes that occur in cottonwood (Populusdeltoides Bartr. ex. Marsh) stems during dormancy induction was investigated. In this experiment, plant dormancy was induced by 8-h photoperiods (short days) and 20 °C: 14 °C temperature regimes. Tissue samples were taken at four stem positions for 8 weeks under short days. Leaf expansion and stem elongation had stopped by the 4th week under short days, and terminal buds had formed. Starch concentration in the lower stem began to increase during the 3rd week and continued throughout the dormancy induction period. By the 8th week starch concentration in the stem was about 24% residue dry weight (RDW). Total nonstructural carbohydrates (starch and soluble sugars) increased almost linearly after the 1st week to about 38% RDW. Free amino acids increased during the first 2 weeks to 1.6%, declined to 0.2% by 6 weeks, then remained constant. Triglyceride concentration remained level for the first 2 to 3 weeks, then increased from 1 to 3% RDW. Changes in the various chemical fractions were sequential and associated with different phases of dormancy induction. Cottonwood, although previously considered a "fat-storing" tree based on histochemical analyses of winter food reserves, stores primarily carbohydrate. Carbohydrate is stored initially as starch and then converted to soluble sugars under cold conditions.
Regression equations for calculating component biomass of young Abiesamabilis (Dougl.) Forbes
Authors: Grier Charles C. , Milne William A.
Published: July 2007

Regression equations for estimating dry weight of new, old, and total foliage; new twigs; live and dead branch; stem wood; stem bark; and wood and bark increment and stem diameter increment from stem diameter were calculated from data obtained by destructive analysis of 57 trees in a 23-year-old, naturally established Abiesamabilis stand in the western Washington Cascades. Regressions are presented and compared with similar regressions based on analysis of mature trees.
Biomass and nutrient removals by conventional and whole-tree clear-cutting of a red spruce – balsam fir stand in central Nova Scotia
Authors: Freedman B. , Morash R. , Hanson A. J.
Published: July 2007

Data are presented of biomass and nutrient removals by conventional and whole-tree clear-cutting of 0.5-ha blocks of an all-aged Picearubens – Abiesbalsamea stand in central Nova Scotia. The biomass yield from the conventional clear-cut plot was 105 200 kg dry weight•ha−1, and the removals of N, P, K, Ca, and Mg were 98.2, 16.3, 91.7, 180.9, and 17.0 kg•ha−1 respectively. Biomass removals from the whole-tree clear-cut plot were 152 500 kg dry weight•ha−1, and the removals of N, P, K, Ca, and Mg were 239.1, 35.2, 132.6, 336.5, and 36.9 kg•ha−1, respectively. These removals of N, P, K, Ca, and Mg from the whole-tree harvested plot, expressed as percentages of the quantities of these nutrients in the "total" pool within the exploitable soil horizons, were 5.0, 2.8, 1.0, 5.9, and 2.1%, respectively. However, when these removals were expressed relative to the quantities in the "available" soil pools, they were much larger, i.e., 500, 34, 184, 306, and 95% for N, P, K, Ca, and Mg, respectively.
Nodule biomass and acetylene reduction rates of red alder and Sitka alder on Vancouver Island, B.C.
Authors: Binkley Dan
Published: July 2007

Three comparisons examined acetylene reduction rate and nodule biomass of red alder (Alnusrubra Bong.) and Sitka alder (Alnussinuata (Regel) Rydb.) on Vancouver Island, British Columbia. The first showed that the acetylene reduction rates of Sitka alder on four sites in early July 1979 varied from 8.8 to 22.0 μmol C2H2•g−1 dry nodule per hour; smaller nodules had the higher rates. In the second comparison, red alder and Sitka alder acetylene reduction rates for young plants were similar when assayed on the same day on the same site. Finally, acetylene reduction rates and nodule biomass were determined for both species growing in closed canopy stands on adjacent sites. In this pair of 20-year-old stands, red alder had double the acetylene reduction rate and three times the nodule biomass of the Sitka alder. Combining the nodule biomass estimates with the seasonal average reduction rates yielded current annual nitrogen fixation estimates (using C2H2) of 130 kg•ha−1•year−1 for the red alder plot and 20 kg•ha−1•year−1 for the Sitka alder plot. These estimates are within published ranges for the species. The lower fixation rate of Sitka alder is still substantial, relative to the nitrogen demands of conifers, and its shrub-like growth form makes it an attractive management alternative to red alder for biological nitrogen fixation in mixed conifer–alder plantations.
Plot, stand, and cover-type aggregation effects on projections with an individual tree based stand growth model
Authors: Moeur Melinda , Ek Alan R.
Published: July 2007

A distance-independent, individual tree based growth model (the multipurpose forest projection system (MFPS)) was used to project changes in stand structure on aspen, red pine, and jack pine cover types in northern Minnesota for 37 years. Individual 0.058-ha plot projections, projections of plots aggregated within stands, and projections of plots aggregated within cover types were compared with each other and with observed plot conditions. Actual plot observations were available for up to 17 years. Individual plot, stand, and cover-type aggregations produced very similar projections in terms of number of trees, average diameter, basal area, and biomass. Plot by plot projections were most accurate in comparison with observed conditions, followed by stand and then cover-type aggregations. Differences from actual values and among projections generally increased with longer projections.
Aspects of statistical bias due to the forest edge: horizontal point sampling
Authors: Fowler Gary W. , Arvanitis Loukas G.
Published: July 2007

A tree-concentric procedure is presented to eliminate edge effect statistical bias for horizontal point sampling. For known forest populations, the exact mean of the unbiased (adjusted for edge effect) and biased (unadjusted for edge effect) estimators of a forest characteristic can be determined along with the exact bias. Edge-effect bias is investigated for three forests that vary in area, four basal area factors (BAF), and three forest characteristics. Exact and estimated results based on 5000 random points were compared. Edge effect bias increases as the BAF decreases and varies with forest size, size and spatial distribution of trees, percentage of edge trees, and forest characteristic. The variance of the biased estimator was always smaller than the variance of the unbiased estimator. Using mean square errors, the biased estimator was found to be, in general, more accurate and the distortion of probability statements caused by the bias negligible for small to moderate sample sizes, especially for larger BAF's and certain forest characteristics.
Biomass production of several jack pine provenances at three Lake States locations
Authors: Zavitkovski J. , Jeffers R. M. , Nienstaedt H. , Strong T. F.
Published: July 2007

Total biomass, biomass production, component distribution, and water content of stems and branches were estimated in 24- and 25-year-old jack pine (Pinusbanksiana Lamb.) stands of four provenances planted at three Lake States locations. The initial spacing was 1.5 × 1.5 m (5 × 5 ft). Total biomass and mean annual biomass production (MAB) were negatively related to location latitude. The overall range of MAB was 2.6–5.8 t•ha−1•year−1 (about 1.2–2.6 tons•acre−1•year−1). The highest MAB was 58% higher than the maximum reported in the literature. Stems accounted for 64–75% and branches with needles for the rest of the aboveground biomass. Stem percentages decreased at the northernmost location. Stems of all harvested trees had a significantly higher water content (127–141% on a dry weight basis) than their branches with needles (100–115%). Water content was the lowest in late winter (March). The study showed that suitable seed source selection is a very important factor in increasing jack pine stand production in the Lake States.
Optimum foliar nitrogen concentration in pine and its change with stand age
Authors: Miller Hugh G. , Miller John D. , Cooper Jean M.
Published: July 2007

Levels of nitrogen in foliage associated with optimum growth of pine were determined in two hydroponic experiments in the glasshouse and two forest fertilizer experiments each designed to cover the full response range for Pinusnigra var. maritima (Ait.) Melv. During the years prior to canopy closure optimum nitrogen concentrations declined with the logarithm of tree weight, falling from 3.3% in very young seedlings to 1.5% in forest trees of 2.0–2.5 m in height. After canopy closure the level increased to about 2.0%. At all stages the concentrations associated with maximum height growth were less than those for maximum volume, weight, or diameter increment. The relationships in the forest experiments, which are on sand dunes in the north of Scotland, could be improved by including factors of rainfall during the previous August and September and of temperature in June of the same year, but this did not alter the optima. It is concluded that for diagnostic purposes critical foliar nitrogen levels must be qualified by the age or developmental stage of the trees.
Above- and below-ground net production in 40-year-old Douglas-fir stands on low and high productivity sites
Authors: Keyes Michael R. , Grier Charles C.
Published: July 2007

Above- and below-ground net primary production was estimated for 40-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands growing on sites with apparently large differences in productivity potential. Aboveground net production was estimated from direct measurements of tree growth; belowground productivity was derived from data obtained by sorting live and dead roots from soil cores used in combination with measurements of root growth on observation windows.Aboveground net production was 13.7 t•ha−1 on the high productivity site and 7.3 t•ha−1 on the low productivity site. Belowground dry matter production on the high productivity site was 4.1 t•ha−1 compared with 8.1 t•ha−1 for the poorer site. On the more productive site, 8% of total stand dry matter production was in fine roots in contrast to over 36% on the poorer site. The difference in total net production (aboveground plus belowground) between the two sites was small (2.4 t•ha−1). Apparent differences in aboveground productivity may, to a large extent, result from the need for a greater investment in the fine roots on harsher sites.
Effects of minor drainages on woody species distributions in a successional floodplain forest
Authors: Buchholz Kenneth
Published: July 2007

A complex gradient of environmental factors exists on river floodplains oriented perpendicular to and affected by the river system. Previous investigations on the development and structure of floodplain forests have not adequately considered the possible effects of minor drainages intersecting the floodplains on vegetation distributions. The density distributions of Fraxinusamericana and Cornusflorida in the lower floodplain region of a portion of the Raritan River system intersected by Chambers Brook in central New Jersey illustrate that minor drainages may be dominant landscape features affecting woody species distributions. Minor drainages appear to primarily affect flooding and drainage patterns and thereby alter the orientation of the complex environmental gradient associated with the river system. When sampling on a floodplain it is important to consider sampling position relative to all drainages to ensure that samples collected at various locations along the floodplain represent similar sets of environmental conditions.
Nitrogen dynamics in the forest floor of interior Alaska black spruce ecosystems
Authors: Weber M. G. , Cleve K. Van
Published: July 2007

Low addition levels of high enrichment isotope (>1% of the total nitrogen pool with 99 at.% excess 15N) were used to follow nitrogen movement through selected forest floor components of permafrost-free and permafrost-dominated black spruce ecosystems in subarctic Alaska. The nitrogen pool examined in this study was the total nitrogen pool. 15N was retained most effectively by the feather moss layer (Pleuroziumschreberi (BSG.) Mitt. and Hylocomiumsplendens (Hedw.) BSG.) on both black spruce sites. Twenty-eight months after isotope application the feather moss layer still contained over 90% of the 15N that could be recovered. The limited movement of 15N between feather moss layers and underlying forest floor horizons appeared to be slightly affected by climatological events. Differences in 15N movement patterns between permafrost-free and permafrost-dominated black spruce sites are discussed in terms of precipitation, soil temperature, and biological controls.
Estimating the total extent of Phellinusweirii root rot centers using above- and below-ground disease indicators
Authors: Wallis G. W. , Bloomberg W. J.
Published: July 2007

The reliability of aboveground indicators, mycelium on the root collar and stain–decay on the stump surface as estimators of the total number of Phellinuswėirii diseased trees and the total area within root rot centers was examined in 25- to 60-year-old Douglas-fir stands.Although variation occurred among stands, aboveground indicators provided a reliable estimate of the total number of diseased trees and of the affected area. Recognizing only trees with aboveground indicators accounted for half the total number of diseased trees and half the diseased area in stands 45 to 60 years of age and half the number and two-thirds the area in 25- to 30-year-old stands. By also including trees with root collar mycelium and (or) stain–decay on the stump surface, a further 25 to 30% of the infected trees and infection area were recorded. However, the reliability of estimating the total number and area was not significantly improved; consequently, the time spent in uncovering and recording the occurrence of mycelium on the collar or stain–decay on the stump surface could not be justified.
The effect of sonication on the growth of some tree seeds
Authors: Weinberger Pearl , Burton C.
Published: July 2007

Air-dry seeds of jack pine (Pinusbanksiana Lamb.), red pine (P. resinosa Ait.), tamarack (Larixeuropaea L.), and white spruce (Piceaglauca (Moench) Voss) were subjected for 30 min to 1 MHz ultrasound at one of three intensities of ultrasound ranging from 0.5 to 6.0 W/cm2. Subsequent germination was assessed in terms of percent germination, mean daily germination (MDG), and peak velocity of germination (PV). From these, germination values (GV) were obtained. Only jack pine responded to the ultrasonic treatments by giving rise to higher MDG and GV values. The seeds were equally stimulated by all the intensities used. The rates and percent germination of the other tree species were unaffected by any of the sonication treatments. Seeds of jack pine were also sonicated at 25, 50, 100, 250, and 750 kHz at an intensity in the range of 0.5–1.0 W/cm2. None of these treatments affected the course of germination.Subsequent seedling growth of all the seeds in all treatment sets was also monitored by summing the total length of all the seedlings following 8 and 14 days of growth. The seedlings were divided into five length-range categories. The jack pine seedlings alone, sonicated at 1 MHz, had significantly more seedlings in the larger size group than the untreated seedlings.
Enhanced root and shoot development of poplar cuttings induced by Pisolithus inoculum
Authors: Navratil S. , Rochon G. C.
Published: July 2007

Cuttings from four poplar hybrids, Populus × cv. Northwest, P. × euroamericana cv. I-45/51, P. × euroamericana cv. DN-21, and P. × cv. robusta superba, were rooted in a medium inoculated with vermiculite-based vegetative inoculum of Pisolithustinctorius (Pers.) Coker and Couch, produced by Abbott Laboratories, Chicago. The addition of the inoculum to the medium resulted in an enhancement in shoot and root development of all four clones. All clones except I-45/51 responded with significantly increased shoot length. At least two of the root characteristics measured, number of roots per cutting, average induced and preformed root length, total root length, and root dry weight, were significantly increased by the addition of the inoculum in three of the clones: cv. Northwest, cv. I-45/51, and cv. DN-21. Cultivar variations in response to the inoculation were evident. Hormonal exudates liberated by the mycelium of Pisolithus are suspected as a cause of the enhanced shoot and root development.
Prediction of snow-water equivalents in coniferous forests
Authors: Harestad Alton S. , Bunnell Fred L.
Published: July 2007

Less snow accumulates under forest canopies than in small openings. Analysis of relationships between canopy cover and snow-water equivalents (SWE) for coniferous forests indicate substantial differences between areas and years. Many of these differences result from differences in the total amount of snowfall. The difference between SWE values in open and forested areas increases with increasing SWE in the open. However, the relative influence of canopy cover on maximum SWE decreases with increasing SWE in open areas. By incorporating this latter relationship, canopy cover can be used to predict snow-water equivalents in coniferous forests.
Biomass and nutrient equations for mature Betulapapyrifera Marsh.
Authors: Jokela Eric J. , Shannon Colleen Ann , White Edwin H.
Published: July 2007

not available
The use of unsaturated salt solutions to generate conifer needle water-release curves
Authors: Livingston N. J. , Jong E. de
Published: July 2007

Reversible changes in cell wall water content, elasticity, and osmotic adjustment are all important drought tolerance mechanisms. Pressure chambers have been used extensively to generate water-release curves from which these basic water relations parameters are derived. Major limitations of this technique include the considerable time required to generate water-release curves and the difficulty in avoiding damage to tissue during the process. A simple and practical technique is descried that overcomes these limitations and allows the routine and rapid generation of water-release curves. Needles were removed from hydrated black spruce (Piceamariana (Mill.) B.S.P.) shoots, weighed on a precision balance, and suspended above unsaturated salt solutions of known molality in sealed test tubes held at 5 °C. Eighteen solutions were used with water potentials ranging from −0.09 to −4.67 MPa. Once needles had equilibrated with air above the salt solution (8–30 h depending on needle age), they were weighed and oven-dried. Water-release curves were obtained by plotting paired values of needle relative water content and solution water potential. Typically, 35 curves were generated over 3 days compared with 7 curves generated using a pressure chamber over the same period. There was excellent agreement between methods in estimates of elastic modulus, osmotic potential, and apoplastic water content.
Influence of dormancy induction treatments on western hemlock seedlings. I. Seedling development and stock quality assessment
Authors: Grossnickle S. C. , Arnott J. T. , Major J. E. , Tschaplinski T. J.
Published: July 2007

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings were grown in a greenhouse and subjected to four dormancy induction treatments (DIT) (i.e., long-day dry, long-day wet, short-day dry, and short-day wet) during midsummer. In the late summer and fall, seedling development was monitored and it was found that (1) short-day DIT caused a rapid cessation of shoot growth; (2) short-day DIT caused rapid fall development of needle primordia, while long-day DIT took until midwinter to produce the same number of needle primordia; and (3) short-day DIT seedlings had lower saturated and turgor loss point osmotic potentials and greater maximum modulus of elasticity in October than long-day DIT. Seedlings were tested with a comprehensive stock quality assessment procedure just before late winter field planting. These tests showed the following: (1) morphological parameters: short-day DIT reduced shoot to root ratios; (2) pressure–volume analysis: short-day wet seedlings had the lowest osmotic potentials at saturation and turgor loss point; (3) soluble sugar analysis: greater levels of total soluble sugars were found in non water stressed DIT compared with water stressed DIT seedlings; (4) seedling water movement: short-day DIT seedlings had the lowest resistance to water movement at low root temperature (5 °C); (5) low root temperature response: short-day compared with long-day DIT seedlings had greater photosynthesis and stomatal conductance at low root temperatures; (6) root growth capacity: seedlings from all DIT were capable of growing roots at optimum root temperature (22 °C), but short-day compared with long-day DIT had greater root growth at low root temperatures; (7) drought stress response: short-day wet seedlings had the highest photosynthesis and stomatal conductance levels as predawn shoot water potentials decreased; and (8) frost hardiness: short-day wet seedlings had the least needle damage when tested at temperatures of −15 and −18 °C.
Water-stress effects on heating-related water transport in woody plants
Authors: Cohen Warren B. , Omi Philip N.
Published: July 2007

Effects of drought-induced water stress on heating-related water transport in three woody plants is examined. By comparing residual water in intact and detached branch tips after heating in a specially designed tree branch calorimeter, and also the energy absorbed during heating, we illustrate that water is transported to heated branch material from unheated material. Similarly, we demonstrate that the amount of water transported is at least partly a function of plant water stress. The implication is that crown fire models do not adequately account for all water vaporized during heating of woody plant crowns.
The perceived security of institutional investment environments of some British Columbia forest tenures
Authors: Luckert Martin K.
Published: July 2007

Changes in forest tenure policies may create insecure investment environments for tenure holders, which can result in misallocations of investment capital. A methodology is developed to measure tenure holders' perceived security in their tenure arrangements. The methodology is applied to three types of tenures in British Columbia. Results indicate that tenure holders perceive Tree Farm Licences and Timber Lands as insecure and Taxation Tree Farms as secure.
Dynamic adjustments in the United States and Canadian construction industries
Authors: Gellner Brett , Constantino Luis , Percy Michael
Published: July 2007

A factor demand dynamic model is estimated for the Canadian and United States construction industries using quarterly data from 1979 through 1986. The model allows for the existence of adjustment costs in the industry, related for example, to the innovative nature of some products. The demand for nonveneered structural wood panels is consistent with the behavior of an innovative product in the United States but not in Canada. A labor–capital composite input is not quasi-fixed in either country. Short-run adjustments, long-run demand elasticities, and biases of technical change are also derived. A decomposition analysis is used to investigate factors underlying the demand substitution of nonveneered structural wood panels for plywood.
Serbian spruce, a narrow endemic, contains much genetic variation
Authors: Kuittinen H. , Muona O. , Kärkkäinen K. , Borzan Ž.
Published: July 2007

Serbian spruce (Piceaomorika (Pančić) Purk.) is reputedly a self-fertile and morphologically uniform species with a natural distribution restricted to a total area of less than 60 ha in central Yugoslavia. This has led to the conclusion that the species lacks genetic variation. In this study, genetic variation at 19 enzyme loci was investigated in two populations: a natural Yugoslavian population and a cultivated Finnish population. The average expected heterozygosities over 19 loci were 0.13 and 0.15 in the two populations, which are similar to those observed in other conifers. Heritabilities of four seedling traits were estimated on the basis of a progeny trial. They varied from 0.34 to 1.23, with standard deviations of 0.17–0.37. Because of maternal effects, these are probably inflated estimates, but they show that there may be considerable genetic variation in quantitative traits, as well. The observed amount of genetic variation in Serbian spruce is unexpectedly high considering its self-fertility and lack of morphological variation. We conclude that drift due to small population size has not had a large impact on the level of genetic variation in this species The lack of morphological variation observed by many authors is probably a result of selection.
Stimulation of flowering by grafted black spruce and white spruce: a comparative study of the effects of gibberellin A4/7, cultural treatments, and environment
Authors: Greenwood Michael S. , Adams Gregory W. , Gillespie Michele
Published: July 2007

Flower stimulation treatments, including gibberellin A4/7 (GA4/7) application, root-pruning, and greenhouse environment during the latter part of shoot elongation, were applied to grafted, clonal black spruce (Piceamariana (Mill.) B.S.P.) and white spruce (Piceaglauca (Moench) Voss) of roughly the same size and age. In addition, the size of pot-grown ramets of both species was increased by inducing additional growth cycles by several applications of a chilling treatment followed by an 18-h photoperiod in a heated greenhouse. This treatment doubled the height growth of both species over a 2-year period, and female cone bud production was promoted by GA4/7. GA4/7 also promoted female flowering on field-grown material, but root-pruning had little effect; black spruce was more responsive to GA4/7 (10× increase) than white spruce (3× increase). Male flowering in black spruce was consistently, and sometimes significantly, inhibited by GA4/7, but was promoted in white spruce. In the latter case the response was not statistically significant. In contrast, male flowering was increased in potted trees of both species by allowing shoots to elongate 50–75% outdoors, after which the trees were moved into a greenhouse.
Radial growth after a shelterwood seed cut in a mature stand of white spruce in interior Alaska
Authors: Youngblood Andrew P.
Published: July 2007

Radial growth following a shelterwood seed cut in a 174-year-old stand of white spruce (Piceaglauca (Moench) Voss) in interior Alaska was compared with growth in an adjacent undisturbed stand of the same age. After a 2-year lag, radial growth of residual trees accelerated an average of 27% in 5 of the next 6 years. Net mean increase in growth after 8 years was 164%. Basal area growth of individual shelterwood trees increased 26.8% over the 14-year posttreatment period, while control trees increased 16.5%.
Effects of Hebelomaarenosa on growth of red pine seedlings in high-fertility nursery soil in Wisconsin
Authors: MacFall J. S. , Slack S. A.
Published: July 2007

Mycorrhizal colonization and growth of red pine (Pinusresinosa Ait.) inoculated with the fungus Hebelomaarenosa Burdsall, MacFall & Albers were investigated in a highly fertile nursery soil. In greenhouse tests, seedlings became mycorrhizal with H. arenosa when inoculum was incorporated throughout the soil to a 1:256 dilution (v/v). Inoculated seedlings had greater root dry weights and root/shoot ratios than noninoculated seedlings. Seedlings that grew in soil where inoculum had been placed around the seeds had greater root dry weights (at a 1:64 dilution) and shoot dry weights (at a 1:4 dilution) than noninoculated seedlings from unpasteurized or pasteurized soil. Hebelomaarenosa inoculum stimulated increased root and shoot dry weights for 2 years compared with noninoculated seedlings mycorrhizal with indigenous fungi. This study supports the hypothesis that H. arenosa can colonize red pine and cause an increase in growth even in highly fertile nursery soils.
Sapwood and heartwood width relationship to tree age in Pinusbanksiana
Authors: Yang K. C. , Hazenberg G.
Published: July 2007

The relationships of sapwood and heartwood width with tree age were studied in 101 trees of Pinusbanksiana Lamb. The sample trees were selected from natural stands growing at various stand densities at the Lakehead University woodlot, Thunder Bay, Ontario, and ranged in age from 6 to 97 years at breast height. The number of rings in both sapwood and heartwood and their respective widths were recorded. The sapwood basal area was expressed as the difference between the stem basal area and the heartwood basal area. A linear relationship was found between tree age and sapwood width, sapwood basal area, and heartwood width. A curvilinear relationship was observed between the number of rings in the sapwood or heartwood and tree age. The number of rings in sapwood increased at an average rate of 0.43 ring per year until the tree reached the age of about 70 years. The number of rings in sapwood was, more or less, constant after 70 years. Heartwood began to form at about the age of 6 years. Heartwood was produced at the average rate of 0.57 ring per year until the tree reached approximately 70 years. After 70 years, the average rate of heartwood expansion was 1 ring per year. It is concluded that tree age is one of the main factors that controls sapwood and heartwood width.
Lack of allozymic variation in disjunct Newfoundland populations of red pine (Pinusresinosa)
Authors: Mosseler A. , Innes D. J. , Roberts B. A.
Published: July 2007

Disjunct, geographically isolated populations of red pine (Pinusresinosa Ait.) on the island of Newfoundland were investigated by enzyme electrophoresis to determine if these populations were genetically distinct from a range-wide sample of mainland populations. Genetic variation at 23 putative gene loci from 12 enzyme systems was assayed by cellulose acetate gel electrophoresis. Each of the 96 trees sampled was monomorphic for all enzyme gene loci assayed, and no genetic differentiation between Newfoundland and mainland populations was detected. The striking lack of genetic variation at enzyme gene loci in red pine has been confirmed for the most isolated populations at the extreme northeastern margins of its range.
Sprouting ability of aerial and underground dormant basal buds of Betulapendula
Authors: Kauppi A. , Paukkonen K. , Rinne P.
Published: July 2007

The effect of ground level on the bursting and development of primary basal buds, formation of secondary basal buds, and survival of sprouts was studied with 2-year-old pot plants of silver birch (Betulapendula Roth) in an experiment in which the ground level was changed. Both intact and decapitated seedlings were manipulated. Raising the ground level reduced the bursting of dormant basal buds, while lowering it promoted both the bursting of buds and survival of the sprouts, especially in the decapitated plants. Many new basal buds developed regardless of the ground level. The intact plants also formed secondary basal buds, but these mostly remained dormant, like old, primary buds. In addition, the concentration of new bud clusters in the uncovered part of the stem suggested that although the plant's internal condition is important for the development and bursting of its basal buds, environmental factors are also involved. Ground-level changes on drained mires and at afforestation sites may significantly affect the success of sprouting.
Dominant-height and site-index equations for ponderosa pine in east-central Arizona
Authors: Stansfield W. F. , McTague J. P. , Lacapa R.
Published: July 2007

A dominant-height equation for ponderosa pine (Pinusponderosa Laws.) was constructed utilizing a parameter prediction method and a model by J.E. King. The site-index equation was obtained by inverting the dominant-height equation. A method was examined for indirectly obtaining parameter prediction equations. It proved superior to two direct parameter prediction approaches. Other site-quality variables, such as habitat type groups and elevation, were included in the dominant-height and site-index equations and were successful in refining predictive capability.
Genetic diversity and structure in Pinuspungens (Table Mountain pine) populations
Authors: Gibson J. P. , Hamrick J. L.
Published: July 2007

Pinuspungens Lamb. (Table Mountain pine) occurs in isolated populations from Georgia to Pennsylvania. Estimates were made of the levels of allozyme diversity within and among 20 populations of P. pungens from throughout its range. Pinuspungens has the high levels of genetic diversity typical of conifer species (0.242) and high intrapopulational diversity (0.204). However, P. pungens has twice as much of its diversity among populations (0.135) as the average conifer species. It is argued that the high degree of stand isolation and the opportunity for genetic drift to occur during succession are major factors contributing to the population genetic structure of this species.
Etiology of a sugar maple decline
Authors: Bauce Eric , Allen Douglas C.
Published: July 2007

Studies in an 85-year-old sugar maple, Acersaccharum Marsh., stand indicated that since the early stages of stand development, sugar maples that are currently declining showed slower growth than healthy trees. A steady growth decline of all dominant trees during the last 30 years was significantly correlated with adverse climatic conditions. High levels of stand density (competition) appeared to predispose sugar maple trees to adverse affects of climatic (winters with periodic thaws and sparse snow cover, summer drought, low autumn soil water recharge) stresses. In some cases, sugar maple decline may be part of a natural stand density regulatory process, and it may be prevented by silvicultural intervention.
Responses of jack pine and black spruce seedlings to inoculation with selected species of ectomycorrhizal fungi
Authors: Browning Mark H. R. , Whitney Roy D.
Published: July 2007

Seedlings of jack pine (Pinusbanksiana Lamb.) and black spruce (Piceamariana (Mill.) B.S.P.) were inoculated with liquid cultures of fragmented hyphae of 10 species of ectomycorrhizal fungi and grown in either aseptic culture tubes for 20 weeks or nonaseptic pots for 16 weeks. Seedlings in pots received more total nutrients and produced larger root systems than those in tubes. Four of the fungi produced higher levels of colonization associated with these larger root systems. Short-root density of black spruce was increased compared with that of uninoculated seedlings by inoculation with Laccariabicolor (Maire) Orton, Hebelomacylindrosporum Romagnési, or Thelephoraterrestris Ehrh. ex Fr. Colonization of jack pine by Rhizopogonrubescens (Tul.) Tulasne, L. bicolor, H. cylindrosporum, or Pisolithustinctorius (Pers.) Coker & Couch resulted in greater short-root densities than in uninoculated controls. Inoculation of potted black spruce with Laccariaproxima Boudier resulted in larger shoot weights and those inoculated with H. cylindrosporum had smaller root weights than did uninoculated seedlings. Both fungi resulted in increased shoot/root dry-weight ratios in black spruce. In contrast with black spruce, seedling weights were not affected by inoculation of jack pine with the same fungal species. However, inoculation of jack pine with R. rubescens resulted in a significantly higher shoot/root dry-weight ratio.
Polymorphic site index equations for four New Brunswick softwood species
Authors: Ker M. F. , Bowling C.
Published: July 2007

As part of a provincial forest site classification program, polymorphic site index equations were developed for Pinusbanksiana Lamb., Piceaglauca (Moench) Voss, Piceamariana (Mill.) B.S.P., and Abiesbalsamea (L.) Mill. in New Brunswick using a generalized version of the Chapman–Richards' height-growth model and data from stem analysis of dominant and codominant trees growing on a wide range of sites. Two generalized five-parameter versions of the Chapman–Richards' model were tested. The resulting equations explain from 96 to 98% of the variation in dominant tree height using breast-height age and site index as independent variables.
Seedling shoot growth of loblolly pine families under two nitrogen levels as related to 12-year height
Authors: Li Bailian , McKeand S. E. , Allen H. L.
Published: July 2007

Seedling shoot elongation and biomass were examined for 23 open-pollinated loblolly pine (Pinustaeda L.) families grown in a greenhouse under two nitrogen regimes. Significant genetic variation was detected among families for the number of growth cycles, total seedling height, cyclic-growth elongation, the number of stem units, and biomass of stem free growth, cyclic growth, total stem, needles, and total shoot. Heritability estimates were generally high for shoot characteristics except for mean stem-unit length. Shoot biomass measures were weakly or negatively correlated with 12-year-height performance. Elongation of cyclic growth, number of growth cycles, and number of stem units showed stronger correlations with field performance than did seedling height. Juvenile–mature correlations were higher for the low nitrogen treatment, suggesting that 12-year height of loblolly pine families can be more accurately predicted when the seedlings are grown under greenhouse conditions that mimic field nitrogen levels.
Physiological indicators of tolerance to cold storage in Sitka spruce and Douglas-fir seedlings
Authors: McKay H. M. , Mason W. L.
Published: July 2007

Two-year-old transplants and undercuts of Piceasitchensis (Bong.) Carr. and Pseudotsugamenziesii (Mirb.) Franco were cold-stored (1 °C) for 1 to 7 months ending in April 1989. Their physiological arid morphological condition at lifting and after storage was assessed and related to survival and height increment on a reafforestation site after one growing season. Physiological assessments made between October and April at lifting were root growth potential, tolerance of fine roots to chronic cold, shoot and root mitotic index, root elongation, and electrolyte leakage from the shoot and roots. Shoot cold hardiness was assessed between October and mid-December. The seasonal changes in these parameters and the effect of species and undercutting treatments are described. At lifting, root growth potential identified (i) differences due to species and undercutting treatments and (ii) the earliest possible safe lifting dates of P. menziesii but not of P. sitchensis. After cold storage, plant vigour was assessed by root growth potential and shoot and root membrane integrity. Membrane integrity of the fine roots was a very good indicator of survival. There was a highly significant, negative correlation between the rate of electrolyte leakage, indicating membrane damage, and survival (p ≤ 0.001, r = −0.90).
Influence of stemflow and throughfall from common oak (Quercusrobur) on soil chemistry and vegetation patterns
Authors: Andersson Thomas
Published: July 2007

Vernal herb vegetation patterns and soil chemistry beneath common oak (Quercusrobur L.) on a former sea bottom with occurrences of calcareous clay on the Swedish west coast were investigated in relation to nutrient addition from bark, stemflow, and throughfall. Nutrient input from bark litter played a negligible role in differentiating soil nutrient and vegetation gradients. Instead, nutrient addition via stemflow seemed to be the main reason for considerably higher pH and calcium content near the stems, and for an altered herb composition, mainly consisting of Mercurialisperennis L. and Hepaticanobilis Mill., in the stem zone of many oaks. The effects of stemflow were not observed around thin-stemmed oaks, nor around oaks growing on soils with high base saturation. This suggests that old, broad-stemmed oaks with deep root systems, reaching more fertile, calcium-rich layers, can redistribute calcium via stemflow, thereby strongly affecting originally nutrient-poor topsoil, and as a consequence, also can regulate the herb composition near the stem.
Effect of trap dimensions on mass of litterfall collected in an Acersaccharum stand in northern Ontario
Authors: Morrison I. K.
Published: July 2007

A comparison of four types of litter traps was conducted during three growing seasons in an old-growth Acersaccharum Marsh, dominated forest on rugged topography in northern Ontario, Canada. The comparison involved traps of two rim heights (0.25 and 1.0 m) and two surface areas (0.25 and 1.0 m2). A supplementary study, also described, compared the two smaller sizes of traps over the same time period. Analysis of variance showed significant effects of both height and surface area on the mass of litter trapped. In a four-way comparison, however, only small traps positioned close to the ground produced estimates that differed significantly from the others. The higher catches associated with these traps are probably the result of a more favorable microsite for entrapment and accumulation of windblown leaves. The number of traps of each type required to constitute a representative sample ranged from ca. 6 to 14 when calculated over three growing seasons. Over the course of a single growing season, the number of traps required increased substantially. No trap type exhibited a distinct advantage in this regard. Generally, however, traps that present a favorable microsite for accumulation of windblown leaves should be avoided in A. saccharum forest.
Aseptic tapping of sugar maple (Acersaccharum) results in light color grade syrup
Authors: Morselli M. F. , Whalen M. L.
Published: July 2007

An aseptic technique was used to collect 227 sap samples from 84 tapholes, including several initial and successive collections, of 27 sugar maples (Acersaccharum Marsh.) over six sap flow seasons (mid-February to late April). In this technique, all material used is sterilized, and the bark as well is sterilized with alcohol. Of the 227 sap samples, 62.5% were sterile or essentially sterile (0–10 colony forming units of microorganisms per millilitre), and of the 74 sap samples from initial collections, 83.8% were sterile or essentially sterile, in contrast with successive collections from the same taphole (P = 0.001). The 35 composite sap samples collected from 1800 nonaseptically tapped tapholes on 900 trees, which were our control, were all contaminated with greater than 800 colony forming units of microorganisms per millilitre. Sap obtained with the aseptic tapping technique produced 92.8% light amber grade syrup and 7.2% medium amber grade syrup. Sap obtained with the traditional tapping technique produced 61.8% light amber syrup, 11.8% medium amber syrup, 14.7% dark amber syrup, and 11.8% syrup that was darker than the dark amber grade. The grade was determined both visually and by a spectrophotometric method. We have substantiated that maple sap is sterile in maple xylem. If sap microbial contamination is minimized and cold sap storage is used, lighter color grade syrup than what is achieved with traditional practices (P = 0.001) can be produced to the end of the season. To avoid the usage of a chemical taphole sanitizer, we recommend cleaner ways for tapping maple trees.
Competitive interactions between the mountain pine beetle and the pine engraver in lodgepole pine
Authors: Rankin L. J. , Borden J. H.
Published: July 2007

The pine engraver (PE), Ipspini (Say), often coexists with the mountain pine beetle (MPB), Dendroctonusponderosae Hopk., in lodgepole pine, Pinuscontorta var. latifolia Engelm. The PE colonizes the upper bole, while the MPB infests the lower bole. We investigated the hypothesis that interspecific interactions between the PE and the MPB within trees can adversely affect MPB progeny production or survival. In lodgepole pine bark attacked by both species, PE and MPB emergence holes had a strong negative interrelationship, suggesting that high numbers of one species resulted in lower numbers of the other. In the laboratory, attacks by PEs on lodgepole pine logs resulted in significantly decreased numbers of MPB progeny, particularly when MPBs and PEs were allowed to attack logs simultaneously. Reductions in MPB progeny were 92.8 and 96.2% when the ratios of attacking beetles were 100 PE: 50 MPB per square metre and 200 PE: 50 MPB per square metre, respectively, compared with that in control logs with 50 MPB per square metre. In an August field experiment, pheromone-induced attack by the PE on trees just attacked by the MPB resulted in a 72.5% reduction in mean MPB progeny production compared with that in MPB-attacked control trees. Possible reasons for the reduced success of MPB when it and the PE coinhabit the same host may be exploitation competition, interference competition, or introduction of fungal competitors deleterious to the MPB. Induced infestation by PEs of MPB-infested trees may have the potential to reduce or control MPB populations.