bluuebunny/crossref_metadata_2025 huggingface dataset:
Scheduling forest core area production using mixed integer programming
Authors: Wei Yu , Hoganson Howard M.
Published: April 2008

Core area, the area of mature forest protected by a buffer area from edge effects of surrounding habitats, is an important spatial measure describing forest ecological conditions. Three alternative mixed integer programming (MIP) formulations are presented for explicitly scheduling core area production in a forest management scheduling model. Formulations utilize detailed data preprocessing that develops a set of influence zones. Each influence zone identifies an area of the forest that can produce core area. Each zone is influenced by a unique combination of management units (stands) of the forest. The assumed width of the buffer surrounding core area affects both the number of zones in the forest and the number of stands associated with each zone. Numerous test cases were applied, varying the MIP formulation used to describe core area production, the assumed buffer for core area (50 or 100 m), and the set of additional forest-wide constraints to control harvest levels and core area production levels over time. Solution times varied substantially between the alternative MIP formulations. Solution times were substantially less for the formulation that used more, but simpler, spatial constraints. Solution times for large test cases suggest that real-world applications are likely feasible.
Variation in cedar leaf blight (Didymascella thujina) resistance of western redcedar (Thuja plicata)
Authors: Russell John H. , Kope Harry H. , Ades Peter , Collinson Heidi
Published: April 2008

Western redcedar ( Thuja plicata Donn ex D. Don) seedlings from a population study with family structure were planted at four sites across coastal British Columbia. All seedlings at the time of planting were infected with cedar leaf blight (CLB) ( Didymascella thujina (E.J. Durand) Maire). CLB severity and tree heights were measured at various ages from 2 to 12 years. There were significant site differences in CLB severity with the coastal hypermaritime site showing the most and with the submaritime site showing the least. Population differences in disease severity were evident with British Columbia coastal, low-elevation populations exhibiting the most resistance and with British Columbia high-elevation and California sources showing the least. Population resistance was consistent across all four sites (all r > 0.90, p < 0.001). Coefficients of additive genetic variation in CLB severity at all four sites varied from 13.2% to 20.1% with narrow-sense heritabilities from 0.21 to 0.66. Type B genetic correlations in CLB severity across sites averaged 0.59. Type A genetic correlations between 6 year CLB severity and height at the Jordan River site on western Vanvouver Island and at the site on the Queen Charlotte Islands were –0.96 and –0.86 (p < 0.001), respectively. Results are discussed with respect to climatic influences and prior exposure to CLB on among- and within-population variation in western redcedar natural populations and impact on gene resource management.
Water use by eastern hemlock (Tsuga canadensis) and black birch (Betula lenta): implications of effects of the hemlock woolly adelgid
Authors: Daley Michael J. , Phillips Nathan G. , Pettijohn Cory , Hadley Julian L.
Published: April 2008

Eastern hemlock ( Tsuga canadensis (L.) Carr.) is a coniferous evergreen species found across the northeastern United States that is currently threatened by the exotic pest hemlock woolly adelgid (HWA; Adelges tsugae Annand). As HWA kills eastern hemlock trees, black birch ( Betula lenta L.) has been found to be a dominant replacement species in the region. Seasonal changes in water use by eastern hemlock and black birch were investigated utilizing whole-tree transpiration measurement techniques. Annual evapotranspiration in an eastern hemlock and deciduous stand was also estimated. During the peak growing season, daily rates of transpiration were 1.6 times greater in black birch. Cumulative transpiration in black birch exceeded hemlock transpiration by 77 mm from June until October. During the dormant season, evapotranspiration rates were higher in the hemlock stand; however, estimated annual evapotranspiration was 327 mm in eastern hemlock compared with 417 mm in the deciduous stand. Our results suggest that a transition from a hemlock-dominated to a black birch-dominated stand will alter the annual water balance with the greatest impact occurring during the peak growing season. Late in the growing season, flow may be unsustainable in streams that normally have light or moderate flow because ofincreased water use by black birch.
Use of different seed tissues for separate biparentage identification of dispersed seeds in conifers: confirmations and practices for gene flow in Pinus densiflora
Authors: Iwaizumi Masakazu G. , Watanabe Atsushi , Ubukata Masatoshi
Published: April 2008

To investigate how accurately biparentage assignments for coniferous seeds can be improved by using different kinds of seed tissues, we assigned biparentage to dispersed seeds in a natural stand of Pinus densiflora Siebold & Zucc. (288 mature trees) using two procedures: with or without megagametophyte haplotype data (“MH” and “ordinary” procedures, respectively). Using archived clones, we confirmed the conifer-specific modes of inheritance of three kinds of seed tissues from certain maternal trees using six microsatellite markers. In the natural stand, under the MH procedure, 39.2% of male parents and 77.0% of female parents for a total of 204 seeds analyzed were assigned to at least one mature tree within the study area. At that time, the proportion of exactly matching seeds out of seeds with one matching parent under the MH procedure was significantly larger than that of the seeds under the ordinary procedure. The biparentage assignments under the ordinary procedure corresponded to only 53.7% of the accurate separate assignments under the MH procedure. It is suggested that analyzing different seed tissues is effective for exact and accurate biparentage assignments in investigations of biparentally mediated gene flow in coniferous populations, particularly at the seed-dispersal stage.
Relationships between climate and double rings in Quercus ilex from northeast Spain
Authors: Campelo F. , Gutiérrez E. , Ribas M. , Nabais C. , Freitas H.
Published: April 2008

The influence of climatic factors on tree-ring width and the formation of double rings was studied in Quercus ilex L. growing in a coppice stand left unmanaged for 22 years. Ten trees were felled and discs were taken every 30 cm from bole and dominant branches. Dendrometer bands were installed on 10 nearby trees and the data recorded were used to confirm the accuracy of our tree-ring identification. They were also used to relate the seasonal radial growth pattern to double-ring formation. Double rings were frequent and occurred consistently along the stem. Two types of double rings could be recognized according to their width: type I, with the extra growth band accounting for approximately 50% of the tree ring; and type II, with a narrow extra growth band. Type I double rings were formed when approximately 1/2 of the growing-season precipitation occurred during the second growth period of the season and after the summer drought. Type II double rings occurred when approximately 1/3 of the precipitation in the growing season occurred after the summer drought. The formation of double rings was triggered by rainfall in summer and the extra growth-band width was related to summer and autumn environmental conditions. Double rings in Q. ilex can potentially be used in dendroclimatological studies, as they are formed in response to climatic conditions within the growing season.
Comparison of fire scars, fire atlases, and satellite data in the northwestern United States
Authors: Shapiro-Miller Lauren B. , Heyerdahl Emily K. , Morgan Penelope
Published: April 2008

We evaluated agreement in the location and occurrence of 20th century fires recorded in digital fire atlases with those inferred from fire scars that we collected systematically at one site in Idaho and from existing fire-scar reconstructions at four sites in Washington. Fire perimeters were similar for two of three 20th century fires in Idaho (1924 and 1986). Overall spatial agreement was best in 1924 (producer’s accuracy = 94% and 68% and user’s accuracy = 90% and 70% for the 1924 and 1986 fires, respectively). In 1924, fire extent from the atlas was greater than for fire scars, but the reverse was true for 1986. In 1986, fire extent interpreted from the delta normalized burn ratio derived from pre- and post-fire satellite imagery was similar to that inferred from the fire-scar record (producer’s accuracy = 92%, user’s accuracy = 88%). In contrast, agreement between fire-scar and fire-atlas records was poor at the Washington sites. Fire atlases are the most readily available source of information on the extent of late 20th century fires and the only source for the early 20th century. While fire atlases capture broad patterns useful at the regional scale, they should be field validated and used with caution at the local scale.
Relating changes in duff moisture to the Canadian Forest Fire Weather Index System in Populus tremuloides stands in Elk Island National Park
Authors: Otway S. G. , Bork E. W. , Anderson K. R. , Alexander M. E.
Published: April 2008

The manner in which trembling aspen ( Populus tremuloides Michx.) forest duff moisture changes during the growing season was investigated in Elk Island National Park, Alberta, Canada. A calibration–validation procedure incorporating one calibration site with moisture sampling across three topographic positions was used to develop predictive models, which were subsequently compared with 12 validation sites across three vegetation types throughout the Park. Duff moisture was modelled against the Duff Moisture Code and Drought Code components of the Canadian Forest Fire Weather Index System. Spring, summer, and fall rates of duff moisture change differed (P < 0.050) during calibration, with moisture loss greatest in spring. Additionally, while moisture changes on the south-facing and crest topographic positions were similar during spring, moisture losses were greater (P < 0.050) at these locations compared with the north-facing landscape position. Correlation analysis indicated that duff inorganic content and bulk density were both related to duff moisture but were limited in importance compared with weather-based influences. When compared with predicted values obtained from calibrated models, moderate predictability of duff moisture was found (mean absolute error = 20.7%–54.2%). Relative to the national standard equations, unique but very different empirical relationships were developed between the Duff Moisture Code and Drought Code and the moisture content of the duff layer in aspen forest stands found in Elk Island National Park.
The changing relationships between forestry and the local community in rural northwestern IrelandAn earlier version of this paper was presented at the IUFRO 3.08 conference “Small-scale Forestry and Rural Development,” 18–23 June 2006, Galway, Ireland.
Authors: Fléchard Marie-Christine , Carroll Matthew S. , Cohn Patricia J. , Dhubháin Áine Ní
Published: April 2008

Following centuries of deforestation, Ireland has undergone a substantial afforestation programme in the last 40 years. This paper presents the results of a case study undertaken to examine local response to afforestation. The study is set in Arigna, a region in northwestern Ireland that has traditionally depended on agriculture but has experienced relatively high rates of afforestation in recent decades. Relying on documentary evidence and in-depth qualitative interviews conducted with local stakeholders, the results suggest more local resistance to afforestation than one might expect in a country that has historically experienced such massive deforestation. Among the reasons uncovered for this resistance is the history of land tenure in rural Ireland, the institutional means by which afforestation has been conducted, the tree species used, and the aesthetic appearance of the forest stands once established. Underlying all of this is an apparently widespread local perception that forestry has benefited outsiders more than locals. Yet, the study also documents local perceptions that those responsible for afforestation have responded to concerns and that resistance to afforestation may be declining, as well as the reasons for this decline. The paper concludes with a discussion of the importance of local history and community involvement in developing socially acceptable forestry.
Natural regeneration and vegetation changes in wet spruce forests after natural and artificial disturbances
Authors: Jonášová Magda , Matějková Ivona
Published: April 2008

An extensive area of Norway spruce ( Picea abies (L.) Karst.) forests in the Šumava Mountains, Central Europe, has been affected by a massive bark beetle ( Ips typographus L.) outbreak since the mid-1990s. One part of the area was left without intervention and two types of intervention have been applied in other parts: (1) the classical forest approach, based on the logging of attacked trees and (2) “sanitation”, in which attacked trees were cut down, debarked, and left lying in the stand. The main goal of our research was to test the impact of nonintervention and both types of intervention on the regeneration of the Norway spruce forests. The Norway spruce forests influenced by natural disturbances (bark beetle outbreak and windfalls) regenerated very well if left without intervention. The bark beetle outbreaks and windfalls do not represent a threat to the long-term persistence of the forests. Clearcuts resulted in formation of pioneer stages with a postponed spruce regeneration. In sanitation plots, the reduction of both previous vegetation and tree regeneration was obvious. Generally, both interventions against bark beetle delayed the recovery of Norway spruce forests.
Why does longleaf pine have low susceptibility to southern pine beetle?
Authors: Martinson Sharon , Hofstetter Richard W. , Ayres Matthew P.
Published: April 2008

Pine forests throughout the world are subject to disturbance from tree-killing bark beetles, but pine species differ in their susceptibilities. In the southeastern United States, Pinus palustris Mill. suffers far less mortality from the southern pine beetle, Dendroctonus frontalis Zimmermann, than do its sympatric congeners. We tested the commonly invoked hypothesis that P. palustris has relatively low susceptibility because it has higher oleoresin flow than other pines, especially Pinus taeda L. However, seven studies in three states over 6 years refuted the hypothesis that P. palustris and P. taeda differ in their constitutive resin flow or in their capacity to replace resin depleted by either experimental wounding or natural beetle attacks. Additionally, surveys of natural beetle attacks revealed that P. taeda and P. palustris were equally likely to be attacked and killed when they cooccurred in front of growing infestations. Thus, the relative susceptibility of these two species changes with the spatial scale at which they are mixed, and the strong landscape-scale pattern of low mortality in P. palustris is not because individual trees are physiologically less susceptible. Ultimately, the conspicuous differential impact of D. frontalis on P. taeda and P. palustris may be the product of coevolution between tree defenses and beetle behavior.
Geographic variation in Prunusserotina
Authors: Carter Katherine K. , Cech Franklin C. , DeHayes Donald H.
Published: April 2008

In 1969, 1-year-old black cherry (Prunusserotina Ehrh.) seedlings from 21 to 33 provenances were planted at each of four locations in the northeastern United States. After 10 growing seasons, survival at each plantation was related to the latitude of the seed source. Differences in height among provenances were not correlated with the latitude of the seed source. Provenance × plantation interaction for height was large, as were differences in mean height among plantations. Differences in leaf characteristics were associated with the location of the seed source, but the pattern of variation in stem form was random rather than regional.
Low-site class black spruce and jack pine nutrient removals after full-tree and tree-length logging
Authors: Weetman G. F. , Algar D.
Published: April 2008

An old, merchantable, low-site class black spruce (Piceamariana (Mill.) B.S.P.) stand growing on a Lithic Humo-Ferric Podzol overlying a granite bedrock, and a younger but merchantable low-site class jack pine (Pinusbanksiana Lamb.) stand growing on a Ferro-Humic Podzol overlying a deep coarse sand near Baie Comeau, P.Q., were analysed for stand biomass and macronutrient contents of both stand and soil. The magnitude of the depletions of macronutrients from the site, in full-tree and tree-length methods of logging, are compared with their available and total quantities in the soil. The range of values from the literature for nutrient inputs are presented and discussed in relation to logging losses. The results suggest that full-tree logging in the dry jack pine stand could cause a severe loss of potentially mineralizable N supply; P, K, and Mg deficiency problems owing to export are not apparent, but a Ca balance problem is apparent. The implication is that full-tree logging should be avoided on such sites.
Mating system of Eucalyptuscitriodora in a seed-production area
Authors: Yeh Francis C. , Brune Arno , Cheliak William M. , Chipman Diane C.
Published: April 2008

Arrays of open-pollinated seeds were assayed for allozyme polymorphisms at three loci (Adh, Gdh, and Mdh-2) to obtain a quantitative estimate of outcrossing rate in a seed-production area of Eucalyptuscitriodora (Hook). Rate of outcrossing varied among loci, but suggested overall that up to 14.7% of the seed might be derived from self-fertilization at the viable embryo stage. Such a level of partial self-fertilization, together with local variation in the mating system, yielded an observed average inbreeding coefficient of 0.205 for these loci in the progeny arrays. By contrast, the mature trees exhibited substantial excesses of heterozygotes (F = −0.300), concordant with but not necessarily supportive of earlier hypotheses that selection against homozygotes through the life cycle occurred in eucalypts.
Formation of organic sulfur in forest soils: a biologically mediated process
Authors: Fitzgerald John W. , Ash Jaru T. , Strickland Timothy C. , Swank Wayne T.
Published: April 2008

The ability of soils from hardwood, clear-cut, and pine forests to incorporate sulfur from added inorganic sulfate into salt-extractable (adsorbed) and nonsalt-extractable forms was investigated. At least 65% of the added sulfate was adsorbed while 8–27% of the sulfate added was recovered only after treatment of salt-extracted samples with acid and base (nonsalt-extractable sulfur). The incorporation of sulfur into this latter fraction was dependent upon incubation time, temperature, and depth and exhibited both spatial as well as seasonal variation in samples taken along a transect of one of the watersheds. Sulfur incorporation into the nonsalt-extractable fraction was inhibited 75–87% by sodium azide, 62–84% by erythromycin, and 41–68% by candicidin suggesting that the process is mediated by bacteria and fungi. Data on factors influencing sulfur incorporation suggest that sulfate was incorporated into organic matter as a covalent linkage and released after rupture of this linkage during acid and base treatment. The observations that 35S incorporation was inhibited 93–99% by unlabelled sulfate and stimulated 21–65% by increased carbon availability are consistent with this suggestion.
Crown architecture of short-rotation, intensively cultured Populus. III. A model of first-order branch architecture
Authors: Burk Thomas E. , Nelson Neil D. , Isebrands J. G.
Published: April 2008

A model was developed to describe the first-order branch architecture of Populus clones grown under short-rotation, intensive culture. Four basic model components describe branch location along the tree bole, orientation of the branch in the plane in which it arises, taper of the branch, and the relation between leaf surface area supported by the branch and branch size. Branch arrangement along the tree bole was found to be symmetric for portions of the bole containing branches. Branch orientation was well described by assuming curvature to be constant, and branch taper was successfully modeled using a simple power function. Branch surface area was determined to be the most appropriate predictor of leaf surface area supported by the branch. Combining the four model components in a computer program allows an analysis of the dynamics of Populus crowns not previously possible.
Root-system morphology of common boreal forest trees in Alberta, Canada
Authors: Strong W. L. , Roi G. H. La
Published: April 2008

Twenty-four specimens of six boreal tree species were excavated: eight Pinusbanksiana Lamb., five Populustremuloides Michx., four Piceaglauca (Moench) Voss, three Piceamariana (Mill.) B.S.P., two Abiesbalsamea (L.) Mills., and two Lara laricina (Du Roi) K. Koch. Root systems were described, and percent biomass determined for above- and below-ground components for half these specimens. Tree ages ranged from 3 to 120 years. Horizontally spreading lateral roots dominated the root systems of all species and occurred within 3– 15 cm of the ground surface. Nutrient and moisture absorption appear to be the principal functions of lateral roots. Maximum vertical root growth occurred near the tree stump as: tap-, heart, sinker, and oblique lateral roots. Vertical root morphology is influenced by site conditions. In addition to providing mechanical support, sinker and taproots may be important adaptations for deep-water utilization on xeric sites. Our data suggest that roots may be important in boreal succession processes through two related mechanisms: (i) nutrient and water deprivation occurring through preemptive growth of tree roots from climax species over roots of serai species, and through interception by mosses; and (ii) niche partitioning occurring below ground between serai and climax, and among climax tree species, by vertical separation of the root systems.
Postemergence weed control in loblolly, slash, longleaf, and eastern white pine nursery seedbeds
Authors: South David B. , Gjerstad Dean H.
Published: April 2008

Pine seedling tolerance to postemergence applications of herbicides was examined in field experiments conducted on loblolly (Pinustaeda L.), slash (Pinuselliottii Engelm. var. elliottii), longleaf (Pinuspalustris Mill.), and eastern white pine (Pinusstrobus L.) at eight southern forest nurseries in 1976 and at five nurseries in 1977. Herbicides suitable for postemergence use are (kilograms per hectare): bifenox, 2.2 and 4.5; acifluorfen, 0.3 and 0.6; oxyfluorfen, 0.3 and 0.6; oxadiazon, 2.2 and 4.4; napropamide, 1.7 and 3.4; butralin, 3.4 and 6.7. Seedling injury to some species was caused by chloramben at 4.5 and 9.0 kg/ha and prometryn at 1.1 and 2.2 kg/ha. Chlorosis was noted with 2.2 kg/ha of perfluidone.
Relative sensitivity of various types of eastern white pine, Pinusstrobus, to sulfur dioxide
Authors: Genys J. B. , Heggestad H. E.
Published: April 2008

Sixteen different types of white pine (Pinusstrobus L.) were exposed for 6 h to 1.5 ppm SO2 in controlled environment chambers in 1979. The specimens, except the controls, were potted grafted seedlings, in active growth when treated. Among nine strains from different geographic regions, the least sensitive were trees from Prince Edward Island, Canada; those from New York, Ontario (No. 75), and Illinois were more sensitive; and the most sensitive were specimens from South Carolina. Among five other types, P. strobus cv. Nana, P. strobus cv. Umbraculifera, Brigham clone, and the control seedlings were moderately sensitive, and cv. Fastigiata was the least sensitive. Two sources treated while dormant were affected less than those in active growth.
Water balance and irrigation planning in a forest tree nursery
Authors: Prévost Marcel , Stein Jean , Plamondon André P.
Published: April 2008

A soil water budget was established to estimate the water loss from the 0- to 60-cm layer as a result of evapotranspiration in a forest tree nursery. Estimated evapotranspiration totaled 69% of potential evapotranspiration (as estimated by the Penman equation) for 36 selected periods from May 15 to July 30, 1975. The root zone (0- to 15-cm layer) supplied 58% of the total evapotranspired water from the soil profile. Evapotranspiration from this layer was found to be a good predictor of total water loss. Evapotranspiration from the root zone, expressed as a percentage of potential evapotranspiration, was related to soil water tension at 3 cm depth. This relationship, combined with a knowledge of soil hydrodynamic properties, can be used to estimate evapotranspiration from the 0- to 60-cm soil profile, which in turn can be used to predict irrigation needs. For practical purposes, a relationship using net radiation instead of potential evapotranspiration can also be used. Depending on the available information, either of these two relationships may be used for irrigation planning.
Fire-related recruitment in stagnant Quercusdouglasii populations
Authors: McClaran Mitchel P. , Bartolome James W.
Published: April 2008

Quercusdouglasii H. & A. (blue oak) age structure, stem analysis, and fire-scar history from more than 500 individuals on two sites in central California, U.S.A., revealed (i) meager tree recruitment since the 1940s and few trees older than 150 years, (ii) increased fire frequency following Anglo-American settlement in 1848 until fire suppression efforts in the 1940s, (iii) a positive association between tree ages and fire dates, and (iv) superior vertical growth to 135 cm of postfire sprouts (trees with ground-level ages within 1 year after fires) on the site with less livestock browsing pressure. We suggest that the association between tree ages and fire dates may have resulted from temporal concentration of postfire seedling sprouts, and faster vertical growth of postfire sprouts compared with true seedlings. However, sampling from existing trees may dampen the difference in vertical growth rates between sprouts and true seedlings where there is heavy browsing, because only true seedlings that grew as fast as sprouts survived and were available for sampling. Our findings contradict previous assumptions of the negative role of fire in Q. douglasii recruitment, and suggest that low recruitment since the 1940s in partly due to fire suppression.
Tree-ring model interprets growth decline in natural stands of loblolly pine in the southeastern United States
Authors: Zahner Robert , Saucier Joseph R. , Myers Richard K.
Published: April 2008

Annual ring widths and ring areas from 131 even-aged, natural, well-stocked stands of loblolly pine (Pinustaeda L.) in the Piedmont region were analyzed to reveal possible causes of a previously reported decline in radial growth. A linear aggregate model was used to separate independent factors that are known to contribute to radial growth variation in this species. Stand, site, and climatic conditions were reconstructed for each stand for the 36-year period 1949–1984 from previous inventories and from weather records at appropriately located stations. Within each of six 5-year age-classes, the model identified declines in both ring width and ring area associated with stand density, climate changes, and the passage of time. Regional climate first ameliorated this decline as pine stands passed from droughty conditions early in the 36-year period to a favorable climate during the middle of the period, and the decline accelerated later with the return of dry conditions toward the end of the period. The tree-ring model simulates a decline in radial increment in trees in natural pine stands between the ages of 20 and 45 years in the Piedmont which has averaged 1% per year since 1950. Part of the downward trend was attributed to increased competition, part to regional drought, and a considerable part to unidentified factors, possibly regional atmospheric deposition.
Temporal changes in tissue water relations of seedlings of Quercusacutissima, Q. alba, and Q. stellata subjected to chronic water stress
Authors: Kwon Ki Won , Pallardy Stephen G.
Published: April 2008

In a greenhouse experiment, seedlings of Quercusacutissima, Quercusalba, and Quercusstellata were subjected to several lengthy drying cycles or were kept well watered. Three times during the 94-day experiment, samples were obtained for pressure–volume analysis of leaves so that tissue water relations responses to long-term water stress could be assessed. There was a general temporal decline in osmotic potential at full turgor (ψπ0) and at the turgor loss point (ψπp) for well-watered seedlings of all species. In water-stressed seedlings, ψπ0 declined from the first (pre-stress) to second sample dates, but then showed a subsequent increase from the second to third sample dates. Despite this increase in ψπ0, ψπp declined in the latter part of the experiment in water-stressed seedlings because of substantial increases in tissue elasticity. The late-period increase in ψπ0 in water-stressed plants was attributable to declines in solute levels and not to increased osmotic volume, as the latter showed a distinct decrease over the experiment. Although slight reductions in ψπp for water-stressed plants compared with values for well-watered plants were noted for Q. acutissima and Q. alba at the second sample date of the experiment, these differences were not significant. By the experiment's end, ψπp values for plants of both treatments were similar for all species. These results indicate that there is a limit to the capacity for solute accumulation under chronic water stress in Quercus, but that compensatory responses of tissue elastic properties may offset this influence.
Climate sensitivity of wood-anatomical features in a ring-porous oak (Quercusmacrocarpa)
Authors: Woodcock D. W.
Published: April 2008

Anatomical characters of the early- and late-wood of individuals of a ring-porous oak (bur oak, Quercusmacrocarpa Michx.) growing in southeastern Nebraska display sensitivity to yearly variations in precipitation. Characteristics of the latewood increment (latewood vessel diameter and density) are closely related to ring width, with vessel diameter varying directly and vessel density varying inversely with ring width. Various analyses indicate that ring width appears to be a less direct climatic indicator than latewood vessel diameter in these trees. A regression equation incorporating latewood vessel diameter is used successfully to reconstruct precipitation over a 9-month period (October–June).
A methodology for estimating canopy disturbance frequency and intensity in dense temperate forests
Authors: Lorimer Craig G. , Frelich Lee E.
Published: April 2008

Analysis of the frequency of past moderate and high-intensity disturbances has been hindered in forests of complex age structure by methodological problems. A methodology is proposed for developing a disturbance chronology in such stands by identifying the probable date of canopy accession for each sample tree. Canopy accession dates are based on an evaluation of radial growth pattern and early growth rates of existing canopy trees. Canopy disturbance intensity is defined as the percentage of sample trees with canopy accession events in each decade. Rotation periods for disturbances of various intensities are calculated from the chronology. The method was evaluated using 893 increment cores from 70 plots in northern hardwood stands of western Upper Michigan. The estimated average disturbance rate for all plots and decades was 5.7–6.9% of land area per decade, with an implied average canopy tree residence time of 145–175 years. These estimates are similar to those obtained by on-site estimates of canopy tree residence time and studies in the literature on the rate of gap formation. Problems in radial increment analysis and possible solutions are discussed.
Linear regression models for biomass table construction, using cluster samples
Authors: Gillespie Andrew J. R. , Cunia Tiberius
Published: April 2008

Biomass tables are often constructed from cluster samples by means of ordinary least squares regression estimation procedures. These procedures assume that sample observations are uncorrelated, which ignores the intracluster correlation of cluster samples and results in underestimates of the model error. We tested alternative estimation procedures by simulation under a variety of cluster sampling methods, to determine combinations of sampling and estimation procedures that yield accurate parameter estimates and reliable estimates of error. Modified, generalized, and jack-knife least squares procedures gave accurate parameter and error estimates when sample trees were selected with equal probability. Regression models that did not include height as a predictor variable yielded biased parameter estimates when sample trees were selected with probability proportional to tree size. Models that included height did not yield biased estimates. There was no discernible gain in precision associated with sampling with probability proportional to size. Random coefficient regressions generally gave biased point estimates with poor precision, regardless of sampling method.
Decomposition of Populustremuloides leaf litter accelerated by addition of Alnuscrispa litter
Authors: Taylor Barry R. , Parsons William F. J. , Parkinson Dennis
Published: April 2008

Decomposition of a slow-decaying litter type is expected to be faster in the presence of a nutrient-rich, fast-decaying litter type, but this effect has never been conclusively demonstrated for deciduous leaves. In a Rocky Mountain aspen forest, we followed decomposition of leaf litter of trembling aspen (Populustremuloides), a relatively slow-decomposing, nutrient-poor species, and green alder (Alnuscrispa), a nutrient-rich, faster-decomposing species, as well as a mixture of the two, for 2 years. Mass losses over the first winter were greatest for aspen alone, probably as a result of loss of solubles, but the mass loss rate overall was lowest for aspen (k = −0.191/year) and greatest for alder (k = −0.251/year). Mass loss rate for mixed litter (k = −0.245/year) was much closer to the rate for alder than for aspen, demonstrating a marked acceleration of mass loss rates in the mixed-litter bags. At these rates, 95% mass loss would be achieved by aspen, alder, and mixed litter in 14.5, 11.5, and 11.6 years, respectively.
Individual tree merchantable volume to total volume ratios based on geometric solids
Authors: Newberry James D. , Burkhart Harold E. , Amateis Ralph L.
Published: April 2008

Individual tree volume ratio equations were developed on the basis of the volume formulas of certain geometric solids. Two parameter-free and two parameterized models were formulated, based on different basal diameters. The parameter-free models should be useful when few individual tree volume ratio data exist for a given species or for a particular population of trees. The parameterized models are appropriate, of course, to those situations where volume ratio data exist. The parameter-free models performed as well as the parameterized models in the upper half of the tree stem for the loblolly pine data used for comparison. The parameterized models performed well all along the tree stem.
Maltol protects against infection of lodgepole pine seedlings by western gall rust
Authors: Blenis Peter V. , Wiggins Kathleen L. , Cunningham James E. , Pickard Michael A.
Published: April 2008

not available
Forest taxation and the timing of private nonindustrial forest harvests under interest rate uncertainty
Authors: Ollikainen Markku
Published: April 2008

The effects of forest taxation (lump sum, unit, and yield taxes) on timber supply are analyzed in a two-period model with an uncertain real interest rate under perfect or credit-rationed capital market conditions. The results differ considerably from the implications in price uncertainty models. First, an uncertain interest rate introduces asymmetry between lenders and borrowers, unknown in those models. Lenders tend to decrease and borrowers to increase forest cutting as a response to interest rate uncertainty. Second, the qualitative effects of timber taxes on supply also differ between the models. The reason for this lies in the change of the source of uncertainty. Interest rate uncertainty implies that the wealth effects of lump sum taxes are not zero even under constant absolute risk aversion, as they are zero under price uncertainty. Third, these differences imply differences in the relative effectiveness of taxes.
Cation binding in wood: applications to understanding historical changes in divalent cation availability to red spruce
Authors: Momoshima N. , Bondietti E. A.
Published: April 2008

The ion exchange characteristics of red spruce (Picearubens Sarg.) bolewood were investigated to understand factors that control divalent cation and H+ concentrations in tracheid cell walls. Vertical concentration measurements of selected cations along the stem demonstrated that the alkaline earths showed the expected chromatographic fractionation, while other cations showed variable patterns relative to calcium. The concentration of cation binding sites (pectates) decreased in a predictable manner from the pith towards the cambium as a function of radius, not chronological age, explaining why in red spruce calcium concentrations are usually highest in the oldest wood. Red spruce wood from Maine and Tennessee had divalent base saturations of about 60 to 65% before the mid-1900s; however, divalent base saturations increased to about 75 to 80% in the mid-1900s, after which they decreased. Wood pH values were highest when divalent base saturation was highest. Calcium and potassium equilibration experiments were conducted, and the results were used to parameterize the Donnan model of cation exchange to understand why base saturation in woody tissues changes in different time periods. Increased divalent cation concentrations in red spruce wood formed during the 1940s to the 1970s are explainable by small increases in both sap pH and divalent cation concentrations and may be the signal of cation mobilization following increasing mineral acid anion deposition from the atmosphere.
A historical perspective on divalent cation trends in red spruce stemwood and the hypothetical relationship to acidic deposition
Authors: Bondietti E. A. , Momoshima N. , Shortle W. C. , Smith K. T.
Published: April 2008

Anomalies in the radial concentration trends of Ca2+, Mg2+, and other divalent cations in the stemwood of red spruce (Picearubens Sarg.) occurred in trees grown in New England, Tennessee, and North Carolina. These anomalies may be assumed to result from changes in sap chemistry. These inferred changes in sap chemistry were the expected result of changes of divalent cation availability in forest soils. The patterns of these anomalies may be interpreted as a signal of a regional mobilization of cations in the rooting zone of red spruce. The anomalous increase in divalent cations present in wood formed in the mid-1900s is coincident both with rapid increases in SOx and NOx deposition in eastern North America and with increases in radial growth increment. The anomalous decrease in divalent cations in wood formed in the late-1900s is coincident with declines in radial increment. Comparisons with divalent cation trends in eastern hemlock (Tsugacanadensis (L.) Carr.), Fraser fir (Abiesfraseri (Pursh) Poir.), and yellow birch (Betulaalleghaniensis Britt. = B. lutea Michx.) suggested that these anomalies were not restricted to red spruce. Radial concentration trends of 90Sr introduced to the environment through radioactive fallout during the 1950s and 1960s were used to investigate the physiology of these divalent cation concentration anomalies. The distributions of 90Sr were also used to estimate the turnover rates for the nutritionally available pools of alkaline earths such as calcium.
Host range and geographic distribution of Armillaria root rot pathogens in the Canadian prairie provinces
Authors: Mallett K. I.
Published: April 2008

A survey to identify Armillaria root rot pathogens, their host range, and geographic distribution was conducted in the Canadian prairie provinces. Collections of basidiocarps and isolates from the wood of gymptomatic or dead trees were made. Armillaria species were identified by interfertility testing and by the L-DOPA method. Three Armillaria species, A. ostoyae (Romagn.) Herink, A. sinapina Bérubé & Dessureault, and A. calvescens Bérubé & Dessureault, were identified. Armillariaostoyae was the most common species in both the subalpine and boreal forests and was found on a wide variety of coniferous and deciduous host species. Armillariasinapina was in both the boreal and subalpine forests but occurred primarily on deciduous host species. Armillariacalvescens was rare and was found only in the boreal forest on both coniferous and deciduous host species.
Successional replacement of old-growth white oak by mixed mesophytic hardwoods in southwestern Pennsylvania
Authors: Abrams Marc D. , Downs Julie A.
Published: April 2008

Presettlement forests in southwestern Pennsylvania were dominated by Quercusalba L. A relatively undisturbed remnant of this forest type on a mesic site was surveyed to investigate the successional status of Q. alba in the region. This old-growth stand is now dominated by Fagusgrandifolia Ehrh., Acerrubrum L., and Liriodendrontulipifera L., representing 62% of the importance value total. Oaks (Q. alba, Q. rubra L., and Q. velutina Lam.) totalled only 18% of the importance value total. The overstory mainly comprised L. tulipifera, F. grandifolia, Q. alba, and Nyssasylvatica Marsh. Acerrubrum and Prunusserotina Ehrh. were the most abundant seedlings, and few saplings of any species were present. The oldest and largest trees were oak, with two Q. alba >300 years. Over 90% of all trees were <120 years old, including many F. grandifolia, L. tulipifera, A. rubrum, and A. saccharum Marsh., but few oaks. Logging of several trees in the 1930–1940s apparently accelerated the speed of obtaining dominance for these mixed mesophytic species. Radial growth patterns varied with species and canopy position. On average, the oldest oaks exhibited slow radial growth of <0.75 mm/year. Many understory trees had average radial growth of >1.5–2.0 mm/year and exhibited a release in growth associated with logging in the 1930–1940s. We believe this forest represents a primary example of an advanced stage of oak replacement by mixed mesophytic species, a process that seems inevitable in many eastern forests.
High temperature effects on apical bud morphology, dark respiration, and fixed growth of blue spruce
Authors: Deal D. L. , Raulston J. C. , Hinesley L. E.
Published: April 2008

Night temperatures during bud elongation affected the fixed growth of preformed subapical buds of blue spruce (Piceapungens Engelm., 'Fat Albert' and 'Foxtail') but not apical bud growth. Plant volume decreased when nights were >14 °C, primarily because of reduced growth of each elongating subapical bud and not a decrease in number of growing points. Apical buds produced under a 30 °C day generally were broader and more flat topped, with more open, noncompressed bud scales than those produced under a 26 °C day. Night temperature had a greater effect on apical bud morphology than day temperature. The extent of bud break and growth during year n + 1 was inversely related to night temperature under which bud initiation and development occurred and directly related to the degree of apical bud normality noted during year n. 'Foxtail' had a greater degree of apical bud normality, a higher percentage of bud break, and retained its characteristic growth habit better than 'Fat Albert' following bud formation at high day and night temperatures. 'Foxtail' also had the lowest respiration rate and appeared to minimize detrimental effects of high temperatures through maintenance of a relatively low respiratory Q10 value (increase in respiration rate for each 10 °C increase in temperature) over a wide temperature range.
Development of large vortices on prescribed fires
Authors: McRae D. J. , Flannigan M. D.
Published: April 2008

A detailed set of data has been compiled on large fire whirlwinds occurring on prescribed burns conducted in Ontario. There appear to be two types of such whirlwinds: one occurs in pairs on the leeward side of the convection column and the other is created after the entire convection column begins to rotate. The second type occurs in association with very intense fires that may be described as fire storms. Fire whirlwind occurrence appears to be related principally to meteorological conditions in which wind speeds are less than 10 km/h, to the stability of the atmosphere up to 3000 m altitude, and to conditions where the amount of energy released from the fire is high. The roles of atmospheric stability, rate of energy release from the fire, and ignition pattern in the development of whirlwinds require further study.
An assessment of pitch pine (Pinusrigida) health and mortality in southern Ohio
Authors: McClenahen James R. , McCarthy Nikki H.
Published: April 2008

The status of pitch pine (Pinusrigida Mill.) health and mortality and relationships between pitch pine vigor or mortality and potential causal factors were studied in natural stands in southern Ohio, and less intensively in northeastern Kentucky, southern Pennsylvania, eastern West Virginia, and the Thousand Islands region of southern Ontario, Canada. High pitch pine mortality was largely confined to the Thousand Islands and ridgetop southern Ohio stands. Mortality was not explained by endogenous site factors on southern Ohio ridgetop sites. Ohio trees with decreased vigor (sparse crowns) also typically exhibited the following: (i) stunted needles; (ii) chlorotic needle mottling that was indistinguishable from O3 and SO2 symptoms induced in laboratory fumigations; (iii) lower total foliar mass; and (iv) higher rates of mortality. The cause(s) of mortality and declining vigor within southern Ohio pitch pine populations remains largely unexplained, but was not associated with pathogens in the bole or main roots, or bark beetle infestation. The possibility that air pollution is acting upon sensitive portions of the Ohio population cannot be ruled out.