bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic control of wood physicochemical properties, growth, and phenology in hybrid aspen clones
Authors: Yu Q , Pulkkinen P , Rautio M , Haapanen M , Alén R , Stener L G , Beuker E , Tigerstedt P MA
Published: April 2011

To better understand the genetic control of wood chemical and fibre properties in hybrid aspen, genetic relationship of these with growth and phenological traits were examined. In all, 18 hybrid aspen clones were sampled in the 13- and 14-year-old clone trials in Sweden. Strong clone within family effects were present for growth and wood properties. The repeatability estimates across two sites were 0.85, 0.65, 0.56, 0.54, and 0.65 for alkali soluble lignin content, arithmetic average fibre length, coarseness, diameter, and height, respectively. Genetic correlations generally exceeded the corresponding phenotypic correlations. The phenotypic and genetic correlations were negative between fibre count and height growth (0.64 and 0.65, respectively) and between fibre count and length of growth period. The result suggests that the length of the growth period could be a good predictor of clone differences in fibre count. The estimated correlations were unfavourable, in the sense that clonal selection directed at increasing the fibre count is expected to produce an indirect genetic decline in growth. Intersite genetic correlations indicated that wood characters were more stable than growth traits.
CommentA re-examination of the effects of fire suppression in the boreal forest
Authors: Miyanishi K , Johnson E A
Published: April 2011

A report by Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305.) is frequently cited in the literature as providing evidence of the effects of fire suppression on the boreal forest. The study is based on 15 years of fire data and stand age data from Ontario, Canada. A re-examination of this report reveals serious flaws that invalidate the conclusions regarding effects of fire suppression on fire size and fire frequency. The fire-size data from the unprotected zone are censored in the small size classes because of detection resolution, invalidating comparisons of shapes of the distributions between the protected and unprotected zones. Use of different plotting scales gives the false appearance of large differences in the number of large fires between the two zones. Stand age data are used to show a change in fire frequency in the 20th century, and this change is attributed to fire suppression. However, no evidence is presented to conclude that this change in fire frequency is attributable to fire suppression and not to climate change. The estimate of the current fire cycle is based on too short a record to give a reliable estimate given the variation in annual area burned. Therefore, this report does not present sound evidence of fire suppression effects and should not be cited as such.
Dendroclimatic analysis of Acer saccharum, Fagus grandifolia, and Tsuga canadensis from an old-growth forest, southwestern Quebec
Authors: Tardif Jacques , Brisson Jacques , Bergeron Yves
Published: April 2011

Radial growth of three tree species (eastern hemlock, Tsuga canadensis (L.) Carrière; sugar maple, Acer saccharum Marsh.; and American beech, Fagus grandifolia Ehrh.) from an old-growth forest, in southwestern Quebec was compared using a dendroclimatic approach. The beech and maple tree-ring chronologies were significantly correlated, whereas the hemlock chronology was correlated only to that of beech. Radial growth of all three species was positively correlated with precipitation and negatively correlated with temperatures during the early summer months of the year the annual ring was formed. This suggests early summer water balance limits the growth of these species on this site. Radial growth of the three species was also negatively correlated with temperatures during the late summer months of the year prior to ring formation. Only hemlock and sugar maple showed a positive correlation with precipitation during the year prior to ring formation. Of the three species, hemlock was most influenced by temperature and showed a positive correlation with winter temperatures. Our results also showed that, since the mid-19th century, certain climatic variables temporarily dominated the growthclimate association of the species. Hemlock showed the most stable growthclimate association, whereas in sugar maple, negative correlations with late winter temperature showed up during the second half of the 20th century.
Assessing large-scale surveyor variability in the historic forest data of the original U.S. Public Land Survey
Authors: Manies Kristen L , Mladenoff David J , Nordheim Erik V
Published: April 2011

The U.S. General Land Office Public Land Survey (PLS) records are a valuable resource for studying pre-European settlement vegetation. However, these data were taken for legal, not ecological, purposes. In turn, the instructions the surveyors followed affected the data collected. For this reason, it has been suggested that the PLS data may not truly represent the surveyed landscapes. This study examined the PLS data of northern Wisconsin, U.S.A., to determine the extent of variability among surveyors. We statistically tested for differences among surveyors in recorded tree species, size, location, and distance from the survey point. While we cannot rule out effects from other influences (e.g., environmental factors), we found evidence suggesting some level of surveyor bias for four of five variables, including tree species and size. The PLS data remain one of the best records of pre-European settlement vegetation available. However, based on our findings, we recommend that projects using PLS records examine these data carefully. This assessment should include not only the choice of variables to be studied but also the spatial extent at which the data will be examined.
Analysis of early tree height in forest genetic trials is enhanced by including a spatially correlated residual
Authors: Costa e Silva João , Dutkowski Gregory W , Gilmour Arthur R
Published: April 2011

This study explores the use of a mixed linear model including spatially correlated residuals in addition to the traditional randomized complete block (RCB) analysis in 12 forest genetic trials. The analysis of early height data from progeny and clonal tests of three species (Picea sitchensis (Bong.) Carr., Pinus pinaster Ait., and Pinus radiata D. Don) showed that there was significant spatial variation in all trials. Adding a basic first-order separable autoregressive error term more effectively modelled the spatial variation than the RCB model and greatly reduced the block and plot variances. There was no evidence that extended spatial modelling was required. The spatial analysis greatly improved the accuracy of genetic value estimation in some trials and was accompanied by large changes in rank of the genetic entries and by greater gains in selection relative to the RCB analysis.
Transpiration Rates of Fraxinusamericana and AcersaccharumLeaves
Authors: Kozlowski T. T. , Davies W. J. , Carlson S. D.
Published: April 2011

Experiments were conducted in the greenhouse and under constant environmental conditions on transpiration rates and stomatal aperture of intact seedlings and excised leaflets or leaves of Fraxinusamericana and Acersaccharum. Leaf surfaces of both species were studied with scanning electron microscopy. Transpiration rates on a leaf area or dry weight basis were consistently higher for Fraxinus than for Acer seedlings. Transpiration rates also were higher in excised leaves of Fraxinus than in those of Acer. The higher transpiration capacity of Fraxinus was associated with larger (but fewer) stomata, less efficient stomatal closure, and less effective cutinization than in Acer. Differences in transpiration rates between Fraxinus and Acer were greater for excised leaves than for intact seedlings. This was largely the result of more rapid stomatal closure of excised leaves of Acer than of Fraxinus. The paramount importance of control of stomatal aperture in influencing internal water balance of plants is emphasized.
Effects of Fertilization and Irrigation on Root Numbers in a Red Pine Plantation
Authors: Farrell Edward P. , Leaf Albert L.
Published: April 2011

A core sampling technique was used for the investigation of root numbers in a 42-year-old red pine (Pinusresinosa Ait.) irrigation – K fertilization experimental area of a K deficient sandy outwash plain in the southeastern Adirondack Mountain Region of New York. Soil cores were collected from plots, 6 years after initiation of treatments, at 0–15 and 15–30 cm depths, using a 5.2 cm diameter corer. Roots were separated from soil cores by a sieving technique. Root tips, including each tip of mycorrhizal structures, were counted by classes established on the basis of morphological characteristics. Numbers of root tips were greater under nonfertilized than fertilized plots, and greater under irrigated than nonirrigated plots. This response pattern did not follow that of wood volume increment, which was greatest in fertilized plots, but was similar to the previously reported pattern in soil microarthropod numbers. The great natural variation observed suggests that root tip numbers may be highly sensitive to changes in soil conditions. Calculated sampling intensity, based on the variance estimates, and specific levels of probabilities (α and β) and allowable sampling error (ε), indicated the need for high numbers of samples.
A Cold Temperature Error in the Pressure Chamber Technique
Authors: Evans A. Kent , Reid C. P. P.
Published: April 2011

Pressure chamber data for Engelmann spruce indicate that a cold temperature error causes artificially low (more negative) xylem pressure potential (Ψxp) values below −0.5 °C xylem temperature. Heat of compression in the chamber causes partial thawing of the frozen sample allowing some water to be forced from the twig at a reasonable, although artificially low, Ψxp value. It is important that the investigator know sample temperature in order not to misinterpret these low Ψxp values as indicative of severe water stress due to decreased absorption of water by root systems at low soil temperatures.
The Error of Area Estimates from Dot Grids
Authors: Bonnor G. M.
Published: April 2011

Tests were made on simulated forest map areas of various sizes and shapes, using dot grids of different densities, to determine if the error of area estimates from single dot counts can be predicted. It was found that the error is closely related to the number of dots in the area and area shape, and that the error can be predicted from these variables with a given statistical probability. It is shown that, from estimates of area size and shape made preliminary to the dot count, a dot grid can be selected such that a specified error will be attained.
Corky Root Disease: Population Fluctuations of Xiphinemabakeri Nematodes, and Disease Severity in Forest Nursery Soil Cropped with Different Seedling Species
Authors: Sutherland Jack R. , Sluggett L.J.
Published: April 2011

Buildup and fluctuations of Xiphinemabakeri Williams nematode populations and disease severity were determined in seedbeds of Sitka (Piceasitchensis (Bong.) Carr.), and white (P. glauca (Moench) Voss) spruces and western hemlock (Tsugaheterophylla (Raf.) Sarg.) and Douglas-fir(Pseudotsugamenziesii (Mirb.) Franco). Population levels were the same on spruces and hemlock, and on coastal and interior forms of Douglas-fir. Numbers of total and female nematodes, and gravid females peaked in September, and May to June, respectively, then declined in late winter and early spring. No post-oviposition increase occurred in early developmental stage nematodes and the nematode overwintered primarily as eggs and juveniles. Total and gravid female population peaks correlated positively with higher ambient temperatures, and the September peak in total nematode numbers coincided with new root-growth of Douglas-fir. Soil moisture had no direct effect on nematode populations.Root disease severity of all seedling species was related to numbers of nematodes per seedling root system throughout the first and second growing seasons, but soil nematode populations for previous and current sampling dates were not correlated with current disease severity. A negative correlation was obtained between nematode numbers per cubic centimetre of root and shoot growth of Douglas-fir.
Diurnal albedo variation of black spruce and sphagnum–sedge bogs
Authors: Berglund Erwin R. , Mace Jr. Arnett C.
Published: April 2011

Diurnal albedo relationships were determined for black spruce (Piceamariana (Mill.) B.S.P.) and sphagnum–sedge bogs in northern Minnesota. Two opposing, cart-mounted, Kipp and Zonen pyranometers traversed a tramway to integrate space and time variations of incoming and reflected solar radiation (waveband 0.3–3.0 microns (μ)).The black spruce stand's diurnal albedo was parabolic. Albedo increased with solar altitude to a maximum at 1200 h (7–8%) and then decreased. Greatest within-season variation occurred during June and September. Canopy roughness was the dominant influence on albedo variation and differences.The sphagnum–sedge type diurnal albedo was M-shaped. A minimum albedo between two maxima occurred at 1200 h. Albedos increased from the 1200-h minimum to each maxima as a result of reported surface 'flattening' effects, increased specular reflection, and changes in solar radiation quality. Albedos before the first and after the second maxima were dominated by the microrelief roughness of the sphagnum–sedge hummocks.
Factors influencing infection and initiation of decay by the Indian paint fungus (Echinodontiumtinctorium) in western hemlock
Authors: Etheridge D. E. , Craig H. M.
Published: April 2011

Sporulation by the Indian paint fungus was maximal during cool, wet periods in the fall. Basidiospores were viable throughout the year, but maximum germination occurred only after temperatures had fallen below 0 °C. It is postulated that infection of western hemlock (Tsugaheterophylla) occurs in spring when a single basidiospore comes in contact with the stub which remains after shade-killed branchlets, about 1 mm in diameter, are broken off at their base. Anatomical studies of branch stub formation showed that this stage is reached around age 40 and that residual stubs must be exposed almost 2 years before they can serve as infection courts. After stub closure, the fungus becomes dormant and can survive in the medullary tissues for up to 50 years or more without causing decay. The possibility is discussed that conditions associated with large branch stubs and other deep-seated injuries, such as logging scars, broken tops, or frost cracks, are responsible for reactivating dormant infections and initiating the decay process. Clarification of the infection mechanism explains observed variations in severity of decay caused by E. tinctorium in different forest associations and provides a simple method, based on host age and stem-ring patterns, for estimating the decay threat in individual trees and stands, without extensive, destructive sampling.
Dispersal and survival of seed of eastern dwarf mistletoe
Authors: Hudler George , French D. W.
Published: April 2011

Seed dispersal of eastern dwarf mistletoe (Arceuthobiumpusillum) parasitizing black spruce (Piceamariana) in the Fond du Lac State Forest, Carlton Co., Minnesota, U.S.A., began in the 1st week of September and continued until the first frost. Most seeds were discharged during the first 3 h after sunrise. Seed expulsion was a function of rising temperature during that time. The mean horizontal distance travelled by discharged seeds was 1.65 m. One seed travelled 13.7 m. Freezing temperatures on August 31, 1970, caused nearly complete fruit abortion in that year of the study and caused a substantial reduction in seed discharge in the other 2 years. Of 3200 seeds placed on the needles of healthy black spruce in September 1971, only 6.5% of the seeds had germinated by August 1972.
A model for determining optimal clear-cut strip width for black spruce harvest and regeneration
Authors: Ek A. R. , Balsiger J. W. , Biging G. S. , Payandeh B.
Published: April 2011

Clear-cut strip width determination for harvest and regeneration operations is illustrated by a deterministic simulation model. Model components are also presented for expressing future strip yields as a function of density in terms of trees per unit area and mean diameter with both of these independent variables varying across the strip. Future density and diameter in turn are expressed as functions of clear-cut strip width, seed dispersal, germination rate, type of seedbed, and survival of the regenerated stand. The model is emphasized as a tool for synthesizing research knowledge for silvicultural decisions. An example for black spruce is developed based primarily on limited data from northern Ontario. Preliminary trials indicate that for any given rotation age of 60 years or more, yields vary little over a wide range of clear-cut strip widths. Suggestions are made for refinement of the model to provide definitive results for more specific geographical areas.
Elements in leaves of a trembling aspen clone by crown position and season
Authors: Verry Elon S. , Timmons D. R.
Published: April 2011

Concentrations of N, Ca, K, P, Mg, Na, Zn, Mn, Fe, Al, B, and Cu were determined in the leaves of a 43-year-old stand of Populustremuloides Michx. by upper, middle, and lower crown positions and for seven sampling dates over the growing season. Concentrations of Ca and K in the upper third crown position were consistently lower than those in either the middle or lower third positions by an average of 0.19 and 0.20% ovendry weight, respectively. Concentrations of Mg and Na remained constant over time; concentrations of N, K, and P continually decreased over time; and minor elements showed a net increase over the growing season with an intermediate peak on June 30. Suggestions for sampling schemes are given.
The effect of wrenching on morphology and field performance of Douglas fir and loblolly pine seedlings
Authors: Tanaka Yasuomi , Walstad J. D. , Borrecco J. E.
Published: April 2011

Second-year Douglas fir and 1st-year loblolly pine nursery stock were undercut and wrenched while actively growing in nursery beds. Their morphology and field performance were compared with Douglas fir seedlings that had been undercut only and with loblolly pine seedlings that had been left intact.The treatment produced shorter, thinner-stemmed loblolly pine seedlings with reduced shoot dry weight. Height, diameter, and shoot dry weight of Douglas fir seedlings were virtually unaffected, but root dry weight was increased substantially. Development of fibrous lateral roots was stimulated in both species. As a consequence, shoot–root ratios were considerably improved, and the seedlings were better conditioned to withstand outplanting. On droughty sites, field survival of Douglas fir was increased by 20 percentage points and loblolly pine by 30 percentage points. Wrenching also extended by several weeks the fall and spring planting periods for loblolly pine and the fall planting period for Douglas fir.
Delayed germination of southern pine seeds related to seed coat constraint
Authors: Barnett James P.
Published: April 2011

The data suggest that constraint by the coat and megagametophyte was an important cause of slowness in southern pine (Pinus spp.) seed germination. As much as 69% of the variation in the speed of germination in five pine species was related to percentage coat weight among the three physical criteria measured. The validity of the constraint concept was supported by higher rates of water and oxygen uptake, increased size of megagametophytes during imbibition, and faster speed of germination of decoated seeds.
Seed production in forests of Chamaecyparislawsoniana
Authors: Zobel Donald B.
Published: April 2011

In 3 years of seed collection throughout the range of Chamaecyparislawsoniana (A. Murr.) Parl., 30 seed crops varied from 20 000 to 4 600 000 seeds per hectare. The overall mean was 829 000 seeds per hectare per year. Annual production per square metre of basal area (BA) varied from 600 to 185 000. Only 6 of 30 seed crops exceeded 50 000 seeds/m2 BA per year but these were produced by the youngest (65 year old) and oldest (450 + year old) stands and throughout the environmental range of the species. Of other seed crops, 11 had 10 000–50 000 seeds/m2 BA per year and 13 had fewer than 10 000 seeds/m2 BA per year. Year-to-year variation had a local, not regional, pattern. An open-forest community produced more seed per square metre of basal area than a denser one at two mixed evergreen zone sites. Seedfall peaked from October to November, with a smaller spring peak, but some seeds fell throughout the year. Most sites differed little in the timing of peaks. Germination of trapped seed from seven sites in 1 year was 11–44% and showed no correlation with crop size. Other species in this genus produce many more seeds per hectare than C. lawsoniana but there is no evidence that seed production limits reproductive potential of this species. In mixed forests, C. lawsoniana and especially Tsugaheterophylla (Raf.) Sarg. were over represented in the seedfall (compared with their basal area), whereas Pseudotsugamenziesli (Mirb.) Franco and Abiesconcolor (Gordon and Glend.) Lindl. ex Hildebr. produced less than their share.
Leaf and twig abscission relationships in a mature white oak
Authors: Chaney William R.
Published: April 2011

Litter fall from a mature white oak (Quercusalba L.) was sampled weekly from August through December for 4 years. Litter was separated into abscised twigs with attached leaves, abscised twigs without leaves, leaves attached to abscised twigs, individually abscised leaves, and acorns. Two phases of leaf fall were evident. The first occurred in early autumn and was characterized by abscission of twigs with leaves still attached. The second phase occurred later in the season and was characterized by shedding of individually abscised leaves. The peak of abscission of twigs with attached leaves preceded the peak of individual leaf fall by 10 to 14 days. Approximately 25% of leaves shed early in autumn were attached to abscised twigs. However, only about 10% of total, annual, leaf litter consisted of leaves lost from the tree while attached to abscised twigs. A significant acorn crop was produced only once during the 4-year study.
Effects of sowing time and container type on height growth and survival of seedlings of Eucalyptusregnans
Authors: Kellas J. D. , Edgar J. G.
Published: April 2011

The height growth and survival of E. regnans F. Muell. seedlings raised in six container types following sowings made at six different times were studied in the nursery and 14 months after outplanting. Seedling height growth during the nursery stage was directly related to container volume and was modified by cold hardening of stems and leaves. Time of sowing influenced survival of outplanted seedlings; however, percentage survival generally satisfied the minimum standard of 1000 trees/ha. The seedlings raised in Jiffy pot 522 (33 mL) were significantly smaller than seedlings raised in Paperpot FH415S (170 mL), Jiffypot 515 (61 mL), Styroblock 2 (40 mL), and Styroblock 8 (125 mL). Container types Paperpot FH415S and Styroblock 8 produced seedlings suitable for present prescriptions of 25–30 cm as required by the Forest Commission in Victoria. However, growth and survival, although variable, were satisfactory for most container types when sown throughout the summer for late winter outplanting.
Shoot elongation of black oak and white oak sprouts
Authors: Johnson Paul S.
Published: April 2011

Weekly events in shoot elongation were observed and measured for 43 black oak (Quercusvelutina Lam.) and 41 white oak (Q. alba L.) sprouts in their second growing season. In addition, total net shoot elongation (i.e., elongation minus current dieback) was measured at the ends of the first four growing seasons. Sprouts originated from stumps with diameters of 0.6 in. (1.5 cm) to 12 in. (30.5 cm). Average net elongation of both species reached a weekly maximum of 0.6 ft (18.3 cm) during the 3rd growth week (May 4–10). Although elongation among individual sprouts was extremely variable, most sprouts of both species flushed two or more times during the 17-week study period. Periods of individual flushes ranged from 1 to 3 weeks and most occurred during the first 13 growth weeks. Based on regression estimates, 2nd-year gross shoot elongation increased with increasing stump diameter up to 6 in. (15.2 cm); above this diameter shoot elongation decreased. Net 4-year elongation of both species also tended to increase with increasing stump diameter up to 6 in. There were no significant differences between species in 2nd-year gross elongation or in total 4-year net elongation.
Effects of thinning and nitrogen fertilization on xylem development in Douglas-fir
Authors: Brix H. , Mitchell A. K.
Published: April 2011

The rates and duration of tracheid production of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were studied by periodic marking of the cambium during two growing seasons. Trees were growing in plots that had been subjected to four treatments, 3 and 4 years previously when trees were 24 years old: (1) control; (2) thinned to one-third the original basal area; (3) fertilized at a rate of 448 kg N/ha; or (4) given the combined thinning and fertilization treatment. From prepared microscope slides of wood sections containing the markings and the previous year's growth, the diameter and wall thickness of tracheids and width of earlywood and latewood were measured for the years since treatment. Rates, but not duration, of tracheid production were highly affected by treatments with maximum radial file productions of 0.80, 1.27, 1.53, and 2.00 cells/day, for the above treatments, respectively. Seasonal changes were related to air temperature until mid-July; some effect of soil water stress was apparent in July–August, and growth cessation was attributed to a short photoperiod. Radial stem growth was more than doubled by the single treatments and this was primarily caused by an increase in cell number, the effects on cell diameter being small. Treatments, except thinning, tended to decrease the percentage of latewood, and thinning increased tracheid wall thickness of earlywood.
Kraft pulp yields and wood properties of fertilized red spruce
Authors: Shepard Jr. Robert K. , Shottafer James E. , Genco Joseph M.
Published: April 2011

Red spruce (Picearubens Sarg.) near Princeton, Maine, U.S.A. fertilized with 168 kg N/h in 1970 increased in volume growth by nearly 50% over pretreatment rates during the 8-year posttreatment period; specific gravity was not affected. Average pulp yield per unit weight of posttreatment wood from fertilized trees was 1.9% greater than average yield from pretreatment wood, but rejects increased by 2.2% and kappa number by 17.7 mL. Average pulp yield per unit weight of posttreatment wood from unfertilized trees was 1.2% less than from pretreatment wood; rejects were 0.4% less and kappa number 2.6 mL higher. Fertilization increased the lignin content of posttreatment wood by about 3% and the resin content by 2%. Ash content also increased after fertilization.
The use of genetic strains in studying the activity and interactions of a fungus inoculated in the stems of living sugar maple
Authors: Basham J. T. , Good H. M.
Published: April 2011

Five auxotrophic mutants of Coniochaetavelutina (Fckl.) Munk, a fungus frequently isolated from defective wood associated with stem wounds of sugar maple (Acersaccharum Marsh.), were selected on the basis of their genetic stability, reliability of identification, and comparable behavior with the wild type invitro. Maple dowels infected with the mutants were inserted in mature, living sugar maple at the site of wounds which had been inflicted with drawknives 5 years earlier. Other nonwounded maple trees were similarly inoculated at two positions with a natural wild type C. velutina isolate and with a mutant strain. Specific mutants were recovered from stem wood directly above or below inoculation dowels in 65% of the attempts made in previously wounded regions and in 100% of those made in nonwounded trees. There was little difference in the rate of spread of C. velutina mutants and the wild type within individual trees. The relative aggressiveness of the five mutants was comparable in both experiments. Despite the long period of time involved in initial experimentation with this technique, the encouraging results suggest that it has promise in overcoming many of the difficulties associated with studies of microorganism activity and interactions within the stems of living trees.
Flowering phenology of Populustremuloides and P. grandidentata and the potential for hybridization
Authors: Pregitzer Kurt S. , Barnes Burton V.
Published: April 2011

Flower phenologies of Populustremuloides, P. grandidentata, and P. ×smithii were monitored for 39 clones in southeastern Lower Michigan, U.S.A., and 73 clones in northern Lower Michigan. In southeastern Michigan the two species were generally found to be reproductively isolated where average flowering times were compared. Populustremuloides exhibited greater intra- and interclonal variation than P. grandidentata and flowered for a significantly longer period. However, overlap in flowering times occurred in southeastern Michigan indicating a potential for hybridization and gene flow. Populusgrandidentata female clones pollinated by P. tremuloides males were most likely to produce hybrid seeds. Small, late-developing female catkins of P. tremuloides also showed strong potential for hybrid seed production. Natural F1 hybrids were intermediate in flowering time between the parents. Therefore, phenology is not a complete barrier to natural backcrossing in southeastern Lower Michigan. Little overlap occurred in northern Michigan, thus strongly limiting the potential for hybridization.
Cone moisture content influences seed release in lodgepole pine
Authors: Hellum A. K. , Barker N. A.
Published: April 2011

Seed release is closely associated with cone moisture content in lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.). Moisture contents varied between 12 and 16% in cones stored in unheated shelters in Alberta. Moisture contents between 15.5 and 18.5% were required to obtain full seed release in bulk lots of cones, depending on the lot. Past research has pointed out the variable nature of cone serotiny in lodgepole pine, and this study suggests that a large part of this variability is due to variable cone moisture.
Predicting root age of advance growth beneath hardwood canopies
Authors: Tryon Earl H. , Powell Douglas S. , Harner E. James
Published: April 2011

Advance growth of seedlings and seedling sprouts is necessary to regenerate certain hardwood species naturally. Also, measurements of abundance, size, and age will help guide silvicultural practices. Root age of advance hardwood regeneration beneath tree canopies is difficult to determine, especially for seedling sprouts. In an attempt to find an easier yet satisfactory method, the use of variables such as root diameter and other tree, stand, and site characteristics were considered. Future predicted values of root age using only root diameter generally were poor, being only within ±6 years or more (95% confidence limits for individual future values (CLI)) for most of the eight species studied. Prediction models for seedling sprouts were then built using variables in addition to root diameter. The prediction of root age was improved. For most species, future root age values could be predicted to within ±4 or ±5 years (CLI), with root diameter and stem age generally contributing the most to R2.
Photographs improve statistical efficiency of truckload scaling
Authors: Demaerschalk J. P. , Cottell P. L. , Zobeiry M.
Published: April 2011

A photographic method is described and tested to improve or replace weight scaling of truckloads of timber on the coast and in the interior of British Columbia. The method uses auxiliary information from colour photographs taken with a 35-mm camera at constant distances from the back and the side of the load. Results reveal that the use of photographic data increases significantly the statistical efficiency of the weight scaling technique. If weight scaling were replaced entirely by photoscaling, required sample sizes (manually scaled) could be reduced by at least 68%. Further study is recommended to evaluate the potential economic advantages of the photoscaling technique in practice.
Protoplast isolation from Ulmusamericana L. pollen mother cells, tetrads, and microspores
Authors: Redenbaugh M. K. , Westfall R. D. , Karnosky D. F.
Published: April 2011

Meiotic protoplasts of Ulmusamericana (American elm) are potentially valuable for producing interspecific elm hybrids through protoplast fusion. Meiotic cells (pollen mother cells, tetrads, and microspores) were incubated in either a cellulase, hemicellulase, and pectinase enzyme solution or a β-1,3-glucanase (laminarinase) solution. Respective protoplast isolation frequencies for the three meiotic cell types were 100, 50, and 10%. Exclusion staining with 0.2% Evans blue and 0.1% methyl blue suggested protoplast viability. Some of the microspore protoplasts were vacuolated, which is an important condition for cell division. Although attempts to regenerate cell walls and induce cell division were unsuccessful, these two problems may be superceded by protoplast fusion with more regenerative protoplasts. To our knowledge this is the first report of protoplast isolation from meiotic cells of a tree species.
Responses of Pinushalepensis seedlings to flooding
Authors: Gomes A. R. Sena , Kozlowski T. T.
Published: April 2011

Pinushalepensis Mill, seedlings adapted poorly to flooding. Soil inundation up to 40 days induced stem swelling and splitting and inhibited dry weight increment of seedlings. Flooding decreased dry weight increment of shoots, largely by inhibiting formation of secondary needles. However, flooding had much greater inhibitory effects on root growth. Flooding inhibited root growth almost completely and also caused some deterioration of the original root system.
Volume, dry weight, and kraft pulping of fertilized balsam fir from Nova Scotia
Authors: Hunt K. , Timmer V. R. , Warren W. G.
Published: April 2011

Volume, dry weight, density, and kraft pulping data were obtained from control and fertilized, mature balsam fir (Abiesbalsamea (L.) Mill.) from Nova Scotia. Fertilization treatments consisted of 450 kg N/ha; 450 kg N and 112 kg P/ha; and 450 kg N, 112 kg P, and 112 kg K/ha, plus the untreated control. Samples were taken at three height positions in trees: stump, breast height, and mid-stem. Wood laid down for 5 years after treatment was separated from wood laid down for 5 years before treatment, and its density determined before being pulped by the kraft process.Fertilization significantly increased volume and dry weight increment and reversed patterns of growth decline during the response period. Any effect specifically due to phosphorous or potassium fertilization over that of nitrogen could not be detected with certainty. Wood density was reduced by N and NP applications; however, pulp yield was unaffected by the fertilization treatments. The need for tree equivalence prior to treatment is stressed for more precise testing of differences.
Changes in mitotic index during onset of dormancy in Douglas-fir seedlings
Authors: Carlson W. C. , Binder W. D. , Feenan C. O. , Preisig C. L.
Published: April 2011

A method is presented for rapid determination of the mitotic index in terminal buds of Douglas-fir, Pseudotsugamenziesii (Mirb.) Franco. Fertilization at planting increased mitotic index but fertilized seedlings entered dormancy at the same time as unfertilized seedlings. Cold storage, prior to dormancy, reduced mitotic index rapidly and was related to reduced height growth the following year. The effects of moderate moisture stress and seed source on mitotic index were slight.
Effect of applied growth regulators on cone production in Douglas-fir, and relation of endogenous growth regulators to cone production capacity
Authors: McMullan E. E.
Published: April 2011

Extracts of buds and young shoots of a good cone-producing clone of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were tested for cone production effect on seed orchard Douglas-fir trees chosen for their history of poor cone production. Other metabolites, including gibberellin 4/7, arginine, and abscisic acid were also tested. Growth regulator levels in good and poor cone-producing clones of Douglas-fir were compared over the period of bud break and shoot elongation.No evidence was obtained for the presence of growth regulators critical to cone production in purified extracts from ramets of the good cone-producing clone. Applied gibberellin 4/7 increased male and female cone production. Crude extracts of a good cone-producing clone increased male cone bud production. Arginine and abscisic acid had no effect.Bioassays indicated that growth regulator levels in buds and young shoots changed greatly with stage of development but were similar in good and poor cone-producing clones.
Effects of four fungicides on survival and growth of containerized Douglas-fir seedlings: greenhouse performance
Authors: Thies Walter G. , Owston Peyton W. , Hansen Dian C.
Published: April 2011

Several disease control strategies were tested on Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings grown in a greenhouse-shadehouse facility in western Oregon. Potting mixture was exposed to two pasteurization treatments combined factorially with four fungicides (benomyl, captan, fenaminosulf, and ethazol) and three application schedules (pregermination drench, postgermination drenches, and a combination of pre- and post-germination drenches). Both pasteurization of the potting mixture and applications of fenaminosulf caused statistically significant phytotoxic effects.
Clonal selection prospects in western hemlock combining rooting traits with juvenile height growth
Authors: Foster G. Sam , Campbell Robert K. , Adams W. Thomas
Published: April 2011

Variation in 1st-year height (HT) of western hemlock (Tsugaheterophylla (Raf.) Sarg.) rooted cuttings was partitioned into environmental and genetic components. C effects, a unique type of environmental effect, was highly significant and made up 8% of the total variation. Much of the variation (21%) resulted from genetic control of HT, producing a broad-sense heritability of 0.81. As reported in a previous paper, initial rooting ability of the rooted cuttings affected the 1st-year height growth of the trees. Genetic correlations between HT and the five rooting traits ranged from 0.37 to 0.59. Using a selection index (assuming 33% selection intensity) containing both HT and a rooting trait (VOL) would result in gains of 8–10% for HT and 20–34% for VOL, depending on relative economic weights for the two traits.
Girdling: an effective and practical treatment for enhancing seed yields in Douglas-fir seed orchards
Authors: Wheeler N. C. , Masters C. J. , Cade S. C. , Ross S. D. , Keeley J. W. , Hsin L. Y.
Published: April 2011

Results of three girdling experiments in operational Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seed orchards, spanning a period of 12 years are summarized. Saw-cut girdles were superior to band girdles for stimulating a cone crop because they were easier to perform, healed faster, and resulted in lower abortion rates in the stimulated crop. Both annual and biennial saw-cut girdle regimens resulted in improved cone yields relative to untreated controls in four successive years. Over that same period of time, cumulative response to annual girdling was greater than to biennial girdling, but in certain response years biennial girdling was best. Girdling had no significant effect on filled seed per cone, filled seed weight, and germination of existing or stimulated crops. There was some indication that repeated girdling increased abortion rates in existing crops but decreased the rate of abortion in the stimulated crop. The long-term effect of repeated girdling on vegetative health and vigor was minor. Flower promotion treatments such as girdling probably improve the genetic quality of orchard seed by creating near-random mating conditions and by preempting unwanted pollen sources.
An integrated approach to individual tree volume distribution and stem profile modeling
Authors: Newberry James D. , Burk Thomas E.
Published: April 2011

Individual tree merchantable volume – total volume ratios with respect to stem diameters and heights on the tree stem were described with the SB distribution. Different volume ratio estimates were obtained from these models for a given location on the tree stem depending on whether the location is indexed by a diameter or height. This problem is common with many volume ratio systems. To overcome this problem, the merchantable volume – total volume ratios with respect to joint stem diameters and heights were described with the SBB bivariate distribution. Error analyses showed that the bivariate distribution had less error than the marginal SB distribution for stem diameters, but more error than the marginal SB distribution for stem heights. A stem taper model was obtained from the conditional distribution of diameter given height using the median regression.
Does the temperature response of rest break of woody plants change during the development?
Authors: Hänninen Heikki , Pelkonen Paavo
Published: April 2011

Preliminary data concerning rest break of buds of 2-year-old seedlings of Pinussylvestris L. and Piceaabies (L.) Karst suggested that (i) an ambient, temperature of 12 °C has a slight rest breaking effect, and (ii) the ability of the rest breaking mechanism to respond to 12 °C is gradually lost when the seedlings are first chilled near 0 °C. This change in the response is interpreted to represent the acclimation of the seedlings to prevailing temperature conditions. A very long forcing period is required to obtain the pattern found by us.
Selection of flood-resistant and susceptible seedlings of Populustrichocarpa Torr. & Gray
Authors: Smit Barbara A.
Published: April 2011

To identify Populustrichocarpa plants with contrasting levels of resistance to flooding, seedlings from five diverse riparian sites were evaluated for growth and survival under flooding conditions. All seedlings survived 6 or 8 weeks of flooding. Total branch length and leaf number were reduced in all flooded plants relative to nonflooded controls. There was also a marked reduction in individual leaf area and increased stomatal resistance of flooded plants compared with nonflooded controls. Growth of flooded and nonflooded plants was highly variable within populations and no significant trends were found among populations. Therefore differential responses to flooding can be selected for within any of the seed collection sites. Plants that were rated as particularly resistant or susceptible fo flooding were selected for further study.
A dimensionless correlation for the spread of wind-driven fires
Authors: Nelson Jr. Ralph M. , Adkins Carl W.
Published: April 2011

Data for the behavior of 59 experimental wind-driven fires were extracted from the literature for use in determining a correlation among several variables known to influence the rate of forest fire spread. Also included in the correlation were unpublished data from six field fires. This information consisted of behavior measurements on small-scale burns of artificial fuels in the laboratory and measurements on field fires in diverse fuels such as grass and logging slash. Fire intensities ranged from about 40 to 4600 kW/m. Dimensional analysis was used to derive three variables governing the fire spread process. These variables, rearranged into a dimensionless rate of spread and a dimensionless wind speed, are strongly correlated and lead to a simple expression for fire spread rate in terms of fuel consumption, ambient wind speed, and flame residence time.
Cyclophytic effects on wood structure in Pinusradiata D. Don. II. Tracheid morphology
Authors: Dodd Richard S.
Published: April 2011

The effects of apical ontogeny on xylem morphology in Pinusradiata were examined in grafted trees and in clonal pairs of trees grown from cuttings from hedge- and tree-form donors (H and T). At the time of sampling the grafted rootstocks were 21 years old, and trees from H and T plants were 11 years old from the date of planting rooted cuttings. In grafted trees tracheids were longer, and the rate of increase in tracheid length was greater above the graft. Since growth rings were narrower above the graft, the difference in rate of increase in tracheid length above and below the graft was greater when plotted against distance from pith than against growth ring number. In comparisons of H and T plants, T plants (expected to be at a later stage of apical ontogeny) produced fewer but longer and wider tracheids. Cell wall volumes per tracheid were greater in T plants, but because the tracheid diameters in H plants were smaller, wall volumes per unit tracheid volumes were consistently greater in H plants. The role of apical ontogeny in explaining patterns of anatomical variation within the stem is discussed. H and T plants of radiata pine were from the three mainland populations: Año Nuevo, Monterey, and Cambria. The Año Nuevo population produced the greatest numbers and the largest tracheids. The Monterey population had the shortest tracheids amongst H plants, but their tracheid lengths were equal to those of the Año Nuevo population in T plants.
Hydrologic soil properties and application of a soil moisture model in a balsam fir forest
Authors: Barry Richard , Plamondon André P. , Stein Jean
Published: April 2011

An analysis of hydrologic soil properties and the prediction of volumetric soil water content during four summers have been done for a site located in the balsam fir (Abiesbalsamea (L.) Mill.) forest of the Lac Laflamme watershed. The hydrologic properties were used to identify three different soil layers, THIRSTY, a soil moisture model using the Penman evapotranspiration formula, was applied to predict daily volumetric water content of these layers. Predictions of soil moisture with the calibrated model were close to the observed data for the median layer (20–60 cm from the soil surface) and less accurate for the surface layer (0–20 cm) where important transpiration activities take place. The model appeared unreliable for predicting soil water content of the bottom layer (60–100 cm) which was often saturated by groundwater. The calibration of the model required modifications of the observed values of the available water content at field capacity and the relative root density factor and was adjusted with the crop coefficient of the Penman evapotranspiration formula. These modifications of observed physical parameters raise the question of the feasibility of extrapolating the model to other sites without extensive calibration. The high sensitivity to variations of the crop coefficient applied to the evapotranspiration equation indicated that a more physically based transpiration model, supported by field-oriented process studies, would be required to improve the model's performance.
Decision analysis for jack pine management
Authors: Martell D. L. , Fullerton J. M.
Published: April 2011

This paper demonstrates how decision analysis techniques can be used to develop a planning methodology that foresters can use to help resolve regeneration and tending decision-making problems associated with the management of jack pine (Pinusbanksiana Lamb.) cutovers on sand flats in the Boreal Forest region of the province of Ontario. The use of the technique is illustrated by applying it to a hypothetical jack pine sand flat cutover that is representative of such sites.