bluuebunny/crossref_metadata_2025 huggingface dataset:
Overstory influences on herb and shrub communities in mature forests of western Washington, U.S.A.
Authors: McKenzie Donald , Halpern Charles B , Nelson Cara R
Published: April 2011

Understanding the relationships between forest overstory and understory communities is essential for predicting changes in the abundance and distribution of understory plants through successional time and in response to forest management. We used correlation analysis, multiple regression, and nonparametric models to explore the relationships between overstory characteristics (canopy cover, stand density, and tree-size distributions) and the abundance of species in the herb and shrub layers in mature forests of western Washington. Overstory variables explained >50% of the variation in the mean response of total shrub cover and ca. 50% of the variation in cover of Acer circinatum Pursh (the most common shrub species) and late-seral herbs (species reaching their greatest abundance in late-successional forests). Stronger relationships (80-90% variance explained) were found between overstory variables and the maximum cover of total shrubs, A. circinatum, total herbs, and each of three functional groups of herbaceous species. These empirical relationships represent both direct resource limitations and time-dependent responses for which overstory characteristics may be surrogates. Models of maximum abundance yielded the most consistent results, suggesting the relative importance of different overstory variables as limiting factors for understory response, although these limiting factors have different effects on plants with different life-history strategies.
High heritability of wood extractives in Pinus sylvestris progeny tests
Authors: Fries Anders , Ericsson Tore , Gref Rolf
Published: April 2011

Pinosylvin, resin acid, fatty acid, and sterol contents were analyzed in north Swedish Scots pine (Pinus sylvestris L.) heartwood from 160 and 44 trees in two full-sib progeny tests, aged 25 and 44 years, respectively. Large variations were found between individual trees, with coefficients of variation of ca. 0.7, 0.8, 0.3, and 0.5 for the four groups of extractives, respectively. Heritabilities were estimated to be 0.5-0.7, ca. 0.6, 0.3-0.8, and 0.6-0.9, respectively, and corresponding genetic coefficients of variation were 0.4-0.8, ca. 0.6, ca. 0.2, and 0.2-0.5, respectively. The results indicate that there is strong genetic control of the wide individual variation, which consequently provides excellent opportunities for genetic improvement. Although similarities in genetic parameters were observed at the two test sites, some differences in total levels of the extractive groups and in their isomeric ratios were detected. This suggests that the genetic control of these features, although strong, may be modulated by environmental factors or other influences, such as the phase of tree development.
Impact of liming on the abundance and vigor of Armillaria rhizomorphs in Allegheny hardwoods stands
Authors: Marçais B , Wargo P M
Published: April 2011

Abundance of rhizomorphs of Armillaria was characterized in 1995-1996 in 32 plots located in sugar maple (Acer saccharum Marsh.) stands in the Susquehannock State Forest (Pennsylvania, U.S.A.). All of the plots were thinned, and half of the plots were limed in 1985 when the plots were established. Frequency and abundance of Armillaria rhizomorphs in soil samples, on dead wood food bases (stumps, snags, fallen logs), and on the root collar of living sugar maples were determined in each plot. Rhizomorph vigor was evaluated by measuring their ability to colonize fresh striped maple (Acer pennsylvanicum L.) stem sections in the soil, or potato tubers in the laboratory. Isolates of Armillaria were obtained from rhizomorphs in the soil samples and species were determined by somatic incompatibility tests. Armillaria calvescens Bérubé & Dessureault was the major species present, representing about 66% of the isolates. Armillaria gemina Bérubé & Dessureault and Armillaria mellea (Vahl:Fr.) Kummer were also identified in the plots. Frequency of rhizomorphs in the soil, on food bases, abundance of rhizomorphs on root collars, as well as the proportion of rhizomorphs per plot that regenerated and (or) colonized fresh substrates were all correlated. However, abundance of ectotrophic rhizomorphs on the root collar was only weakly correlated with the other components of rhizomorph abundance and vigor. Frequency of the rhizomorphs as well as their ability to colonize fresh substrates were greater in plots either limed or with a high proportion of the basal area in sugar maple prior to thinning. By contrast, abundance of ectotrophic rhizomorphs on root collars was not affected by these factors.
Dispersal and viability of seeds from cones in tops of harvested loblolly pines
Authors: Shelton Michael G , Cain Michael D
Published: April 2011

Seed supply is one of the most important determinants of successful natural regeneration. We conducted a study to determine the potential contribution of cones in the tops of harvested loblolly pines (Pinus taeda L.) to the stand's seed supply if trees were felled after seed maturation but before dispersal. Closed cones, collected in October 1996, were stored in wire cages with periodic removals over 2 years to determine the number and viability of extracted seeds. Storage sites were an opening in a seed-tree stand and a closed-canopy pine-hardwood stand in southeastern Arkansas. Of the initial 83 viable seeds/cone, 73% had dispersed in the opening and 63% in the closed stand by March 1997, which is considered the end of the normal dispersal period from standing trees. By October 1997, only 1 viable seed/cone remained in the opening and 5 viable seeds/cone in the closed stand, indicating rather complete dispersal or mortality of seeds by the first summer after harvest. Results indicate that cones in tops of trees cut during the 2-month period after seed maturation and before substantial dispersal can make an important contribution to the stand's seed supply, especially in reproduction cutting methods where most of the trees are harvested.
Estimating maximum mean canopy stomatal conductance for use in models
Authors: Ewers B E , Oren R , Johnsen K H , Landsberg J J
Published: April 2011

Fertilized (F) and irrigated and fertilized (IF) stands of Pinus taeda L. produced twice the leaf area index of irrigated (I) and control (C) stands. Based on sap flux-scaled mean stomatal conductance (GS), we found that stomatal conductance in F was half that in other treatments. During the growing season, GS was related to vapor pressure deficit (D) and soil moisture. During the cooler season, soil moisture was high and light accompanied D in controlling GS. Under all conditions and treatments, the rate of decrease in GS with D was proportional to GS at low D (= 1 kPa). We evaluated whether GS can be used as an input to growth models and used a simple growth model (3-PG), which also predicts stand transpiration (EC), to compare with direct EC measurements in the four stands. Model predictions of monthly EC based on Penman-Montieth equation parameterized with maximum GS (GSmax) estimated under highest "native" soil moisture (0.07 m3·m3) produced long-term values within 10% of measured EC. When the model was parameterized with GSmax estimated under experimentally raised soil moisture, or with porometrically measured conductance, EC values were consistently overpredicted from 12 to 33%. Thus, sap-flux scaled mean canopy stomatal conductance obtained under non limiting light conditions, low D, and highest native soil moisture, is the most appropriate parameter value for certain single-leaf type of models.
Vertical distribution and radial growth of coarse roots in pure and mixed stands of Fagus sylvatica and Picea abies
Authors: Schmid Iris , Kazda Marian
Published: April 2011

The vertical distribution of roots greater than 2 mm diameter was determined from digital images covering 116-m2 profile walls in soil pits in pure stands of European beech (Fagus sylvatica L.) and of Norway spruce (Picea abies (L.) Karst.) and in a mixed stand of both species. Radial root growth was assessed for roots greater than 5 mm diameter by growth ring analysis. Beech roots showed maximum density at the 10- to 20-cm depth, whereas the density of spruce roots decreased exponentially with increasing soil depth. Roots of both species reached the maximum excavation depth (1 m) in their monospecific stands. However, the root system of spruce was shallower in the mixture with beech, where large roots (diameter (d) >20 mm) were limited to the upper 10 cm. Beech roots reached the same rooting depth as in the pure stand but showed higher root densities in deeper soil layers. Neither root diameter nor root growth of any species was correlated with soil depth. Radial root growth of beech exceeded that of spruce significantly in both pure and mixed stands. Radial growth rate of beech roots further increased when mixed with spruce. The enhancement of beech root growth in the mixed stand suggests a higher belowground competitive ability of beech compared with spruce; as a result the spruce root system developed even shallower in the mixed versus in the pure stand.
Above- and below-ground effects of aspen clonal regeneration and succession to conifers
Authors: Shepperd Wayne D , Bartos Dale L , Mata Stephen A
Published: April 2011

Above- and below-ground characteristics were measured and compared for six sets of paired trembling aspen (Populus tremuloides Michx.) clones on the Fishlake National Forest in central Utah. Three self-regenerating clones were compared with three non-regenerating clones and three pure aspen stands were compared with three mixed aspen-conifer stands. Regenerating clones had dense understories of younger aspen stems, which were not present in non-regenerating clones. Regenerating clones also had greater numbers of roots and greater total root surface area than non-regenerating clones. Aboveground biomass and growth of the aspen in mixed stands was less than that of pure stands. A corresponding difference in aspen root mass was not apparent, indicating that the decline of aspen in mixed stands had not yet affected the root system. Conifer height and basal area growth rates were clearly greater than those of aspen, suggesting that aspen will eventually disappear from these forests in the absence of stand-reinitiating disturbances.
Individual tree detection in digital aerial images by combining locally adaptive binarization and local maxima methods
Authors: Pitkänen Juho
Published: April 2011

Locating local maxima of grey levels in aerial images was used for individual tree detection in boreal, closed forest conditions in southern Finland. Image smoothing and binarization were used as preprocessing steps. Binarization was used to restrict the local maxima searching to the bright areas of the images, which were assumed to be tree crowns. Because brightness variations are typical of aerial images, both within and among images, locally adaptive methods were suggested for binarization. Aerial digital camera images and mapped tree data of eight stands in three field plots were used. Four adaptive binarization methods were compared. Differences in tree detection accuracy were small even though the appearance of the binarized images were different. Image smoothing improved the results of tree detection in the three stands that had the largest mean tree size. Tree detection worked fairly well in all seven stands with a density of less than 1500 trees/ha. In these stands, 7095% of the trees were detected, whereas only 54% were detected in the last stand, which had a density of approximately 1900 trees/ha.
The use of forest maps for the description of wildlife habitats: limits and recommendations
Authors: Dussault Christian , Courtois Réhaume , Huot Jean , Ouellet Jean-Pierre
Published: April 2011

We evaluated the reliability of forest maps for describing wildlife habitats. During the summer of 1997, we sampled 186 boreal forest stands located in Jacques-Cartier Park, Quebec. In each stand, we measured slope, crown closure, basal area, as well as tree height and age. We determined if map classifications, with regard to dominant species composition, density, tree height, tree age, and slope, correlated with field observations. We also measured lateral cover and deciduous browse availability, variables that are considered useful for the characterization of wildlife habitats, to examine how these habitat features were related to map classification. Age (57% of the sites correctly classified) and density (34%) were the variables for which map classification had the best and worst correspondence with field measurements, respectively. Dominant species on maps were correctly identified in <74, <55, and <40% of the sites in coniferous, mixed, and deciduous stands, respectively. The use of a simple classification method based on cover type alone resulted in improved correlations, since 94, 60, and 29% of the coniferous, mixed, and deciduous stands, respectively, were properly identified on maps. We related lateral cover and food availability to stand categories using the most reliable map variables. We conclude that forest maps are useful for describing major habitats at the stand level. When forest resource maps are to be used for studying habitat suitability, we recommend sampling a subset of stands to assess if important wildlife habitat features, which reflect species requirements, can be related to habitat characteristics as determined by the maps.
Manipulation of density of Pseudotsuga menziesii canopies: preliminary effects on understory vegetation
Authors: Thysell David R , Carey Andrew B
Published: April 2011

Managing second-growth forests to conserve biodiversity has been proposed by both foresters and conservation biologists. Management, however, can have unintended consequences, including reduction in native species diversity and increased invasion by exotic species. Our goal was to determine if inducing heterogeneity in managed forest canopies could promote a diversity of native species without contributing markedly to invasion by exotic species. We examined 1- and 3-year responses of understory plants to variable-density thinning of 55- to 65-year-old stands of Pseudotsuga menziesii (Mirb.) Franco. Our study stands had been managed either with retention of old-growth legacies (large live trees, dead trees, and fallen trees) and no thinning or with removal of legacies and twice-repeated conventional thinning. Variable-density thinning initially resulted in decreased understory cover but increased importance of 20 native species, including 2 species of trees. Two native species, however, decreased in importance, and 11 exotic species increased in importance. Within 3 years, understory cover recovered, species richness increased by >150%, only four exotic species persisted with increased importance, eight native species (including four graminoids) increased in importance, and seven native species decreased in importance. Variable-density thinning shows promise as part of holistic silvicultural systems applied across landscapes throughout stand rotations and as a technique to restore vegetative complexity to closed-canopy second-growth forests.
Long-term trends in growth of Pinus palustris and Pinus elliottii along a hydrological gradient in central Florida
Authors: Foster Tammy E , Brooks J Renee
Published: April 2011

Forest species composition in Florida is sensitive to changes in hydrology that accompany small shifts in elevation. In this study, we use dendrochronological techniques to determine how the growth of Pinus elliottii var. elliottii Engelm. (slash pine) and Pinus palustris Mill. (longleaf pine) along a hydrologic gradient from mesic flatwoods to xeric sandhills responds to fluctuations in climate (temperature, precipitation, river flow, and Palmer drought severity index). Interspecies and intraspecies comparisons of growth responses were made between a xeric P. palustris plot, a transition zone plot containing both species, and a mesic P. elliottii plot. Growth of P. elliottii individuals was negatively correlated with increased water availability on sites with a shallow water table (<1 m) but positively correlated on sites with a deeper water table. The basal area increment (BAI) of P. elliottii individuals on the drier site was 41% lower than the BAI of individuals on the wetter site. In contrast, the growth response of P. palustris, which only grows in the dryer sites, was similar along the hydrologic gradient, with growth being positively related to water availability and only a 16% lower BAI on the driest site.
Using landscape metrics to measure suitability of a forested watershed: a case study for old growth
Authors: Lundquist John E , Lindner Larry R , Popp John
Published: April 2011

Several metrics for spatial heterogeneity based on distribution of stands suitable for old growth were calculated for the actual and optimal conditions of a watershed in the Medicine Bow National Forest in Wyoming. Optimal conditions were based on expert opinions. The actual condition was compared with target conditions using a multivariate method called profiling, which develops profiles based on various spatial statistics and examines the similarity of these profiles using a multidimensional scaling (MDS) procedure. Profiles for various target landscapes clustered together in MDS space, and this space could be defined and quantified using a kernel density estimator. The distance from the centroid of the target space to the position of the actual stand is used as a measure of dissimilarity. By comparing the condition of a given watershed to that of what experts envisioned would be optimal, we argue that the relative condition of the watershed can be characterized. We make a distinction between stand-scale metrics and landscape-scale metrics. We propose that this method may be useful in quantifying changes in landscape conditions and could be useful as a monitoring method in forest plans.
Temporal and spatial variation of nitrogen transformations in nitrogen-saturated soils of a central Appalachian hardwood forest
Authors: Gilliam Frank S , Yurish Bradley M , Adams Mary Beth
Published: April 2011

We studied temporal and spatial patterns of soil nitrogen (N) dynamics from 1993 to 1995 in three watersheds of Fernow Experimental Forest, W.V.: WS7 (24-year-old, untreated); WS4 (mature, untreated); and WS3 (24-year-old, treated with (NH4)2SO4 since 1989 at the rate of 35 kg N·ha1·year1). Net nitrification was 141, 114, and 115 kg N·ha1·year1, for WS3, WS4, and WS7, respectively, essentially 100% of net N mineralization for all watersheds. Temporal (seasonal) patterns of nitrification were significantly related to soil moisture and ambient temperature in untreated watersheds only. Spatial patterns of soil water NO3 of WS4 suggest that microenvironmental variability limits rates of N processing in some areas of this N-saturated watershed, in part by ericaceous species in the herbaceous layer. Spatial patterns of soil water NO3 in treated WS3 suggest that later stages of N saturation may result in higher concentrations with less spatial variability. Spatial variability in soil N variables was lower in treated WS3 versus untreated watersheds. Nitrogen additions have altered the response of N-processing microbes to environmental factors, becoming less sensitive to seasonal changes in soil moisture and temperature. Biotic processes responsible for regulating N dynamics may be compromised in N-saturated forest ecosystems.
Holocene vegetation and natural disturbance in the Engelmann Spruce  Subalpine Fir biogeoclimatic zone at Mount Kobau, British Columbia
Authors: Heinrichs Markus L , Hebda Richard J , Walker Ian R
Published: April 2011

The vegetation and natural disturbance history of the Mount Kobau area, in the Engelmann spruce (Picea engelmannii Parry ex Engelm.)  subalpine fir (Abies lasiocarpa (Hook.) Nutt.) (ESSF) forest of southern British Columbia, was reconstructed using pollen, plant macrofossils, and microscopic charcoal. Late-glacial vegetation, occurring from about 11 000 14C years BP, consisted of an Artemisia steppe under a cold and dry climate. Rapid warming occurred at the start of the Holocene, approximately 10 000 to 9500 years BP, and grassland steppe vegetation prevailed. Moisture increased during the mid-Holocene, from approximately 7000 to 3800 years BP, and fires may have occurred more widely and burned more severely. Open lodgepole pine (Pinus contorta Dougl. ex Loud.) parkland occupied the mountain summit. Late-Holocene cooling at 4000 years BP resulted in the establishment of modern ESSF forest. The vegetation and inferred climate history confirm a broad three-stage (warm dry  moderate moist  cool moist) regional climatic pattern of the Holocene. Under future anticipated climate change, the high-elevation, dry ESSF forests in southern British Columbia may be replaced by grasslands.
Vertical Distribution of Xiphinemabakeri Nematodes in Soil in a Douglas-fir Nursery
Authors: Sutherland Jack R.
Published: April 2011

Soil samples were collected throughout the year to determine the vertical distribution of Xiphinemabakeri nematodes in soil in a Douglas-fir [Pseudotsugamenziesii (Mirb.) Franco] nursery and to monitor seasonal changes in nematode distribution pattern. Root distribution, moisture content, available pore space, and osmotic pressure were also determined for soil samples taken at various depths to see if they were related to nematode distribution. More than 90% of the nematodes were present in the upper 20 cm of soil, especially from 0 to 10 cm, and this percentage did not change with season. Nematode distribution was related only to root distribution. The significance of the results for nematode control practices is discussed.
Effects of Environment on Growth and Survival of Douglas-fir Transplants
Authors: Tregunna E. B. , Crown M.
Published: April 2011

Variation in lifting date, planting date, planting site, seedling history, root treatment, and storage time were tested for their effects on Douglas-fir transplants. Survival, water status, types of damage, and both shoot and root growth were measured. Survival decreased with later spring planting date in the field, but this was partly offset by trends in browsing. Survival was greater at the lower elevation. Differences in seed lot, or conditions in the nursery, resulted in differences in tree size, which had some effects because the larger trees were browsed more. Survival and growth were not markedly different between root treatments. Cold storage increased survival of trees lifted late in the spring. The relative turgidity of leaves from bareroot trees in storage was related to lifting date and subsequent survival. Survival decreased severely as lifting date progressed through March.
Photosynthesis and Carbon Dioxide Transfer Resistance of Lodgepole Pine Seedlings in Relation to Irradiance, Temperature, and Water Potential
Authors: Dykstra Gary F.
Published: April 2011

Photosynthesis and stomatal and total equivalent mesophyll resistances to CO2 transfer were measured in relation to irradiance, needle temperature, and tree water potential. Maximum rates of net photosynthesis were attained at 380 W m−2 irradiance, 20 °C needle temperature, and the highest tree water potential obtained, ca. −2.5 bars. Stomatal and total mesophyll resistances have a significant rate-limiting role when environmental conditions are less than optimum. Mesophyll resistance was larger than stomatal resistance under all environmental conditions.
Inhibition of Root- and Butt-decay Fungi by Extractives of Balsam Fir Root Wood
Authors: Sterner Thomas E.
Published: April 2011

Growth of the root- and butt-decay fungi, Coniophoraputeana, Polyporusbalsameus, Scytinostromagalactinum, and Odontiabicolor, was significantly less on root centerwood than on stem heartwood of balsam fir. Also, root centerwood was much more resistant to decay than was stem heartwood. The inhibitory properties of the root wood were markedly reduced by chloroform extraction, and the concentrated extracts inhibited the growth of the decay fungi. Through bioassay, most of the inhibition was found to be attributable to four of the several spots appearing on chromatograms of the extract neutral fraction.
Performance After Planting of Four Types of Container-grown White Spruce Seedlings
Authors: Hocking D. , Endean F.
Published: April 2011

Four types of container-grown white spruce (Piceaglauca (Moench) Voss. var. albertiana (S. Brown) Sarg.) seedlings were produced by rearing to two ages and applying two different moisture and nutrient regimes. They were planted at three field sites and in a controlled environment with cooled rooting zone, two soil textures and two moisture levels. Growth after 12 weeks was related to a variety of initial seedling characteristics in an attempt to identify predictive characteristics useful for assessing seedling quality.The oldest, most fertilized and irrigated and hence largest seedling type performed best under all test conditions, both in terms of survival and growth. There were no interactions between seedling type and treatment conditions. All initial characteristics were strongly predictive of subsequent characteristics except shoot/root ratio and number of white root tips.A set of rearing conditions are specified suitable for white spruce container seedlings in central Alberta.
Root and Shoot Development on Cuttings of Basswood (Tiliaamericana L.) as Affected by Auxin Treatments and Size of Cuttings
Authors: Morsink W. A. G. , Smith V. G.
Published: April 2011

A population of saplings of basswood was studied to determine the effect of size of cutting and a 2-min basal dip in an aqueous solution of either indolebutyric acid (IBA), indoleacetic acid (IAA), or naphthaleneacetic acid (NAA) on root and shoot development of softwood cuttings grown under intermittent mist. Cuttings were 12–60 cm long, and treatments were: distilled water control; and aqueous solutions of auxin at levels of 1000, 5000, 10 000, and 20 000 p.p.m. Significant increases in the growth of roots were obtained with 5000 and 10 000 p.p.m. of IBA. Significant increases in root growth were also obtained with increasing sizes of cuttings.
Effect of Mid-day Shading on Stem Diameter, Xylem Pressure Potential, Leaf Surface Resistance, and Net Assimilation Rate in a White Oak Sapling
Authors: Hinckley T. M. , Chambers J. L. , Bruckerhoff D. N. , Roberts J. E. , Turner J.
Published: April 2011

The diurnal relationship between xylem pressure potential and stem diameter in white oak (Quercusalba L.) resulted in a hysteresis loop on clear days where, for a given level of xylem pressure potential, the stem was thinner upon rehydration than during dehydration. Cloudy days complicated this pattern by forming a loop within the main loop. This additional loop was caused by the same factor which caused the main loop, the delayed reaction or lag between changes in stem diameter and xylem pressure potential. Both net assimilation rate and leaf surface resistance were closely linked and responded rapidly to changes in radiation. Hydroactive increases in leaf surface resistance were observed as xylem pressure potential decreased below −23 bars. A discussion of the relationship between stem diameter, radiation, leaf surface resistance, and xylem pressure potential is presented.
Airborne Fungal Spores at Lumber Seasoning Yards in the Lower Ottawa Valley
Authors: Ünligil H. H. , Shih M. S. H. , Shields J. K.
Published: April 2011

Airborne fungal spores were trapped at three lumber storage locations in the lower Ottawa Valley by exposing petri dishes containing malt agar medium. The fungal colonies developing were counted and identified. Highest counts from morning exposures were obtained at Braeside in June, at Ottawa in July, and at Thurso in September. Afternoon exposures, made only in Ottawa, yielded generally higher counts than morning exposures. While dark colonies predominated at Ottawa and Braeside sites, where mainly softwood lumber was stored, hyaline and white colonies prevailed at the hardwood lumber yard at Thurso. The three most common fungi at the Ottawa and Braeside locations were Alternaria spp., Aureobasidiumpullulons, and Penicillium spp. At the Thurso site, Alternaria spp., Trichodermaviride, and Penicilliumspp. were most numerous. A Cladosporium sp., a Graphium sp., and an Alternaria sp., caused considerable staining on the surface of white birch blocks in laboratory tests.
Effects of Partial Girdling on Growth in Lodgepole Pine with Application to Damage by the Weevil Hylobiuswarreni Wood
Authors: Cerezke H. F.
Published: April 2011

Leader growth and radial increment on the stem and main lateral roots during three consecutive years following partial girdling treatment were analyzed on 25- to 30-year-old lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) from a natural stand in west-central Alberta. Simulation of the larval feeding wounds of the weevil, Hylobiuswarreni Wood, consisted of the removal of a 7-mm-wide band of bark from 0% (control), 20%, 40%, 60%, 80%, and 90% of the root-collar circumference of 58 sample trees.Partial girdling reduced leader elongation and radial increment of the leader and lateral roots. Leader height decreased with increased girdling of the root-collar during each of the three post-treatment years. Below the leader, partial girdling of the root-collar did not affect radial increment in the first year, caused an increase during the second year, and a decrease in the third year. At 2 cm above the partial girdles, radial growth above the girdled side of stems was always less than that on the nongirdled side and showed a trend of increase with increased girdling on both girdled and nongirdled sides of the stem. Radial increment was considerably reduced on lateral roots extending below girdle wounds during the three post-treatment years. Two graphs are prepared which can be used to estimate height and radial increment losses in young pine stands infested by H. warreni.
Longitudinal Variation of Specific Gravity in Stems of Black Spruce, Balsam Fir, and Lodgepole Pine
Authors: Heger L.
Published: April 2011

The relationship between disc specific gravity (dependent variable) and relative disc height was investigated for 50 black spruce (Piceamariana (Mill.) B.S.P.), 50 balsam fir (Abiesbalsamea (L.) Mill.), and 36 lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.). The sample trees represented various geographic areas and sizes. The simplest polynomial adequately describing the relationship was a parabola whose minimum was at mid-stem in spruce and fir and at 70% of the total height in pine. The linear term was significant only in pine and could be detected with 95% confidence if at least 14 trees were sampled. The quadratic term could be detected with 95% confidence if at least 48 spruce, or 8 fir, or 38 pine were sampled. It was concluded that the conflicting evidence in the studies concerned with the longitudinal variation of specific gravity in species of the genus Picea may be due to insufficient sample size of trees. Deviations of the sample averages from the fitted values exhibited a pattern that was similar for each species. This similarity suggested that the action of factors governing wood structure in stems of conifers depends more on the relative height in the stem than it does on species, geographic area, and absolute size.
Développement de Odontia bicolor chez le sapin baumier infecté artificiellement
Authors: Lachance Denis
Published: April 2011

In a balsam fir stand, two different humus moisture conditions were artificially produced and maintained for 2 years by covering the forest floor with polythene sheets on two out of four plots. In the two covered sample plots the water saturation of the humus layer was 30% lower and the moisture contents of root-wood was 35% lower than those of uncovered plots. Roots in covered plots, inoculated with Odontiabicolor, showed 51.4% infection as compared to 57.7% for those growing in control plots. Similarly, trunk inoculations yielded infection levels of 35.8% and 44.5%, respectively. Statistical tests show no significant difference in infection percentages between wetter and drier conditions for roots and trunks, and a significantly greater susceptibility to infection of the roots by O. bicolor as compared to the trunks. Growth rates of the fungus toward the trunk (in the roots) or up the trunks of 4.4–5.8 cm per year was 25–44% greater than growth in the opposite direction. Root and trunk sizes had no definite influence on infection percentages and growth rate, but the latter was always faster in trunk wood than in root wood.
An Input–Output Model of Ontario Forest Based Industries
Authors: Raizada H. C. , Nautiyal J. C.
Published: April 2011

A simple static input–output table of the forest based industries in Ontario for the year 1969 is presented. It shows the interrelationships between various timber products activities in the provincial economy and provides information on the origin and destination of the outputs and cost structure of individual sectors. Implications of changes in consumption of various forest products of Ontario on the income generated in the province are briefly discussed and ways of using the model for other purposes are shown. Features of a more detailed model that should be constructed for Ontario are enumerated.
Within-crown Variation of Sitka Spruce Polyphenols
Authors: Forrest G.I.
Published: April 2011

The variation in polyphenol concentration was studied in current year's shoots taken at different heights from young trees of Sitka spruce, and in 2-year-old branches taken from various parts of older trees. Polyphenol variation with shoot position was caused by variation in the ratio of leaf to stem material in the different shoots. In the older trees, polyphenol variation was small, but definite trends associated with height were found, particularly in the patterns of stilbene accumulation. The material showing minimum variation and having high stilbene levels, and hence being of most value for routine sampling, was 2-year-old lateral branches taken from the upper part of the tree. A comparative analysis of several provenances showed that this material furnished data compatible with those previously obtained from current year's shoots.
The Distribution of Photoassimilated Carbon and the Growth of Douglas-fir Seedlings
Authors: Webb Warren L.
Published: April 2011

Two-year-old Douglas-fir seedlings accumulated photoassimilated carbon in the tissues of new needles, previous years' needles, new shoots, stem, and roots at rates relative to tissue carbon of 1.25, 0.57, 0.42, 0.60, 0.61%/d, respectively. These daily net accumulation rates were measured just after bud set, and the rates parallel the carbon accumulation expected based on phenological observation. Results were obtained with a new system for long-term labelling of groups of seedlings with 14CO2 at a constant specific activity. This system is described.
Effect of Moisture Stress on Germination and Radicle Development ofPinuseldarica Medw. and Pinusponderosa Laws.
Authors: Djavanshir Karim , Reid C. P. P.
Published: April 2011

Polyethylene glycol (PEG-4000) was used to study the effect of substrate water potential, ranging from 0 to 20 negative bars, on the germination of Pinusponderosa and P. eldarica seeds over a 35 day period. A marked reduction in percentage germination and germination value (GV) occurred at −4 bars for P. ponderosa and −6 bars for P. eldarica and optimum germination occurred at −2 and −4 bars, respectively. The best radicle growth (elongation) occurred at −2 bars for both species, but was severely reduced at potentials −4 bars or less. Although germination occurred at potentials as low as −8 bars for P. ponderosa and −12 bars for P. eldarica, it was estimated that percentage seedling survival would be near zero at these moisture stresses because of a marked reduction in radicle growth.
The Absorption of Fenitrothion During Germination of Stratified and Nonstratified White Pine Seeds and Identification of Metabolites Formed
Authors: Hallett D. J. , Greenhalgh R. , Weinberger P. , Prasad R.
Published: April 2011

White pine seeds, P. strobus were treated with a 1.5 × 10−4 M solution of fenitrothion, 0,0-dimethyl-0-(4-nitro-3-methyl-phenyl)-phosphorothioate. The seed coat, endosperm, and embryo were monitored for residues of the insecticide and metabolites during germination and early seedling growth. Absorption and accumulation of fenitrothion, and accumulation of fenitro–oxon, and S-methyl fenitrothion were demonstrated in the endosperm and embryos of germinated seeds and seedlings. Neither the parent compound not its metabolites adversely affected the later development of the pine seedlings.
Interactions of P, Mn, and Cu in Nutrient Uptake by Sugar Maple
Authors: Gysi C. , Winget C. H. , Bernier B.
Published: April 2011

Uptake of P from nutrient solutions by excised roots of sugar maple wildlings was stimulated by Mn and inhibited by Cu. A reciprocal inhibition of uptake was observed between Mn and Cu. Future studies of sugar maple nutrition in both artificial and natural growth media should anticipate the possibility of similar effects.
Archy and Diameter of Primary Xylem in Horizontal and Vertical Roots of Red Pine
Authors: Fayle D.C.F.
Published: April 2011

In root systems of red pine from two plantations, horizontal roots up to 10 m long and vertical roots to nearly 3 m deep in the soil were primarily diarch but triarch and tetrarch portions occurred. Average primary xylem diameter (PXD) of main horizontal roots increased from 0.25 mm near their base to over 0.60 mm at 3–5 m, declining to 0.55 mm by 7 m. PXD of deep vertical roots showed a similar increase with distance from their origin; there was always a drop in PXD between the parent horizontal root and its vertical branch. Substantially increased PXD in shallow vertical roots may have been caused by the high bulk density ( > 1.40) of the soil. The occurrence of 'split' primary and secondary xylem is described.
A comparison of mature with recently clear-cut and scarified lodgepole pine forests in the Lower Foothills of Alberta
Authors: Corns Ian G. W. , Roi George H. La
Published: April 2011

Mature, even-aged lodgepole pine (Pinuscontorta Dougl. var latifolia Engelm.) forests on upland sites with Orthic Gray Luvisols in the Lower Foothills of Alberta have been clear-cut for pulpwood and scarified by bulldozer since 1958. Undisturbed stands had weak shrub strata, well developed herb – dwarf shrub strata, and continuous feather moss strata.In 25 clear-cut stands 6–12 years old, the average cover of vascular plants was 54% and did not change significantly during the sampled age interval. Cover of tree 'regeneration' (immature size classes) was 5%, increasing slowly, and codominated by lodgepole pine and aspen (Populustremuloides Michx.). Shrub cover was also 5% and dominated by prickly rose (Rosaacicularis Lindl.). Herb – dwarf shrub cover was 44% and dominated by nine species of the mature forest. Bryoid cover was 13 %.The density of young trees stabilized within 6 years after clear-cutting, and the above-ground biomass of both pine and aspen increased rapidly during the sampled age interval.An ordination of the clear-cut stands showed that the distribution and abundance of several important plant species were well correlated with soil moisture on two gravimetric sampling dates in summer.A comparison of dominance–diversity curves and indices for mature and clear-cut stands revealed that the clear-cut community was richer in vascular species (100 cf. 57) and had a more even distribution of cover among species.The early stages of secondary succession after clear-cutting and scarification of lodgepole pine forest are discussed.
Leaf area differences associated with old-growth forest communities in the western Oregon Cascades
Authors: Gholz Henry L. , Fitz Franklin K. , Waring R. H.
Published: April 2011

Total leaf area varied from 20 to 42 m2/m2 in 250- to 450-year-old forest communities developed under different temperature and moisture conditions. The largest values were in communities at midelevations where winter snowpack accumulated and growing-season temperatures were cool. Shrub and herb leaf area varied from 3% to 14% of the total. Equations for converting from foliage biomass to surface area are included for most species encountered.
The effect of prescribed burning on some physical soil properties of jack pine sites in southeastern Manitoba
Authors: Sims H. P.
Published: April 2011

The effect of prescribed burning on physical soil properties of clear-cut areas originally supporting jack pine (Pinusbanksiana Lamb.) was studied in southeastern Manitoba.Average temperatures recorded during three burns ranged from <52 °C at 5-cm depth to 300 °C at the mineral soil – humus interface. The most severe burn increased the weight of organic horizons by 7% because of deposition of fuel residues, while the least severe burn produced a 31% reduction in the weight of the organic mantle.Soils at 3.8 and 7.6 cm under burned seedbeds reached permanent wilting point at days 9 and 23 respectively during a 30-day rain-free period. Moisture contents at similar depths on an adjacent scarified area were significantly higher than on the burn, were much less variable, and remained above permanent wilting point for the duration of the 30-day period. Burning did not significantly affect percolation rate.
Selection cutting in over-mature spruce–fir stands in Quebec
Authors: Weetman G. F. , Algar D.
Published: April 2011

On the North Shore of the St. Lawrence River in the boreal forest (Forest Section B.1b) there are extensive stands of old-growth black spruce (Piceamariana (Mill.) B.S.P.) and balsam fir (Abiesbalsamea (L.) Mill.). They grow on high-quality valley-bottom sites with a diameter class distribution that is close to the theoretical ideal of the straight-line log relationship considered ideal for selection forests.In 1962, two stands containing about 3500 ft3/acre (246 m3/ha) on 36 acres (14.5 ha) were cut to remove between 20% and 50% of the volume in the form of a selection cut. Basal area and volume, growth, ingrowth, mortality, logging damage, and blowdown losses were monitored in two 5-year remeasurements on a network of 72 permanent sample plots. Only 18 of these plots showed a net loss in basal area for the 10-year period after treatment.It is concluded that in sheltered locations it could be possible to maintain stands such as these in a productive and aesthetically pleasing condition by careful selection cutting.
Vegetation, site, and fire relationships within the area of the Little Sioux fire, northeastern Minnesota
Authors: Nordin John O. , Grigal David F.
Published: April 2011

The relationships among various landscape features were examined in an area in northeastern Minnesota that burned in a forest fire in May 1971. Maps based on fire intensity, cover types in 1948 and 1970, soils, and topography were randomly sampled. A total of 34 comparisons were made between pairs of classifications based on the mapped characteristics. The closest relationship was between dominant vegetation in 1948 and that in 1970. Relationships between soil mapping units and slope position and between vegetation and soils were also relatively high. The vegetation–soil relationships were influenced by the close associations of lowland vegetation to lowland soils and of upland vegetation to upland soils. However, specific categories of upland vegetation were not well related to specific categories of upland soils. Fire intensity was most closely related to slope position. An 80% decrease in balsam-fir cover types occurred from 1948 to 1970. This decrease was accompanied by a nearly equal increase in aspen cover types. This balsam-fir to aspen cover type change is attributed to the spruce budworm epidemic, which occurred from the mid-1950's to the mid-1960's. Decreases in jack pine, red pine, and white pine cover types are attributed to commercial logging.
The use of product form in form-class volume equations
Authors: Smith V. G.
Published: April 2011

This paper describes studies on testing of form-class volume equations in tree-length logging operations where upper-tree diameters are easily measured, and it investigates a modified procedure for estimating the relationship between diameter and the product of form and length. Stacked wood measurements for some 84 piles of spruce–fir tree lengths, obtained on four different logging operations in Newfoundland and Labrador in 1973–1974, were compared with corresponding estimates obtained by using regional volume, standard volume, form-class volume, and product-form volume equations.Product-form volume equations gave more accurate estimates than any of the other equations for these data.Regional volume/diameter equations were more accurate than the standard volume equations and were on a par with the conventional form-class volume equations. Regional volume/diameter equations should be used when the cost of developing local volume tables from sample observations is too great.
Red pine foliage variation and field sampling intensity
Authors: Berglund John V. , Leaf Albert L. , Leonard Raymond E.
Published: April 2011

Three sources of variation are considered for their effects on measured variability in foliar analysis of plantation-grown red pine and the concomitant effects of this variability on sample size determinations. The influence of temporal (year-to-year), spatial(site), and treatment (fertilization and irrigation) response variation is discussed. The results indicate that there is a need for a high sampling intensity when the risk, α, that the actual error would be larger than the allowable error, ε, is set at equal to or less than 0.05 and the allowable error, ε, is set at equal to or less than ±10% of the mean for all foliage parameters studied. They also indicate that treatments tended to induce heterogeneity of variances of foliar measurements, increasing the number of samples required at specific risk and allowable error levels over those required if variances on treatment and control plots were homogeneous.
Estimation de la production de jeunes plantations de pin rouge et de pin gris du sud du Québec
Authors: Bolghari H. A.
Published: April 2011

Multiple regression equations have been developed to predict yield from young red pine and jack pine plantations. Data from 446 sample plots representing young red pine and jack pine stands located on the south shore of the St. Lawrence River between Quebec and Montreal were analysed. The red pine plantation yielded more than the jack pine. However, in plantation both species yield more than in natural stands. Taking into account the age and spacing of the sampled plantations, the equation obtained can provide information on yield of red pine and jack pine stands the maximum spacing of which is 3 × 3 m, up to the age of 45 and 35 years respectively. The equations will allow the construction of preliminary yield tables for both species.