bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic variance of early height growth and expected gains from selection in a Minnesota population of black spruce
Authors: Nelson C. Dana , Mohn Carl A.
Published: July 2007

A genetic improvement project for black spruce (Piceamariana (Mill.) B.S.P.) was initiated in Minnesota in 1974, with an objective of improving the inherent growth rate of the local population. This study reports some field results from the initial phase of the project. Study objectives were to (i) estimate genetic and environmental variance components of early (age 10 years) tree height, (ii) estimate expected genetic gains from various selection methods in three seedling seed orchards and a clonal seed orchard, and (iii) evaluate the effect that these selection methods have on inbreeding levels in the rogued seedling orchards. Additive genetic variance accounted for 15 to 22% of the phenotypic variance in three wind-pollinated family tests and 10% of the phenotypic variance across the tests. Expected gains from combined-index (family and individual) selection in the family test - seed orchards (selection of 22 to 27%) ranged from 4.6 to 6.1%. Family + within-family selection and individual selection were 18 and 32% less efficient, respectively. Index selection resulted in the highest estimated levels of inbreeding in the rogued orchards. However, the largest difference between the various selection methods resulted in a difference in the average inbreeding coefficient of less than 0.15%. Based on this small difference, index selection could be used in roguing similarly designed seedling seed orchards with minimal risk of elevated inbreeding levels.
Effects of thinning on the allocation of growth and respiration in young stands of balsam fir
Authors: Lavigne M. B.
Published: July 2007

The current annual growth of foliage, branches, and stems per unit of foliar weight was approximately the same in unthinned stands of young balsam fir (Abiesbalsamea (L.) Mill.) and stands thinned 4–6 years earlier. Foliage, branches, and stems accounted for approximately 30, 30, and 40%, respectively, of aboveground growth in the thinned and unthinned stands. The allocation of photosynthates to stems was estimated by adding the carbon used for respiration to that used for growth. The proportion of photosynthetic production allocated to stems was greater in an unthinned stand than in a thinned stand. The additional proportion of net photosynthetic production allocated to stems in the unthinned stand was used for maintenance respiration. Since the photosynthetic production per unit of foliar weight of thinned stands should equal or exceed that of unthinned stands, differences in the proportion of photosynthates allocated to stems between these stands imply differences in the proportion of photosynthates allocated to other tree components. Therefore, it appears that a larger proportion of photosynthates was allocated to branch respiration and (or) roots in thinned stands than in unthinned stands.
Nitrogen mineralization characteristics of forest floor organic matter on slash-burned sites in coastal British Columbia
Authors: Fyles J. W. , Fyles I. H. , Feller M. C.
Published: July 2007

Nitrogen mineralization characteristics of the dominant types of organic matter in the forest floor of slash-burned sites were measured using a 26-week aerobic incubation. Six classes of forest floor material were distinguished on the basis of morphology and N mineralization characteristics. Fermentation layer materials, matted together with fungal hyphae, had a high content of total and potentially mineralizable N (N0) (7804 and 2816 μg/g, respectively) and mineralized the most N during incubation (1605 μg/g). Decayed wood had the lowest level of total N (1816 μg/g) and N0 (195 μg/g) and mineralized the least N (266 μg/g) despite a high inherent mineralization rate (k) (0.16). Humified materials (Hd and Hr) occupied a midrange, with the exception of those from thin residual horizons, which had high N0 values (2246–6009 μg/g) and low k-values (0.005–0.012). The significant differences in N mineralization among organic materials that are morphologically or ecologically distinct in the field suggest that it may be possible to assess site N fertility using intensive forest floor and soil survey data and information on the N characteristics of dominant horizon types.
Near-normal, empirical, and identity yield tables for estimating stand growth
Authors: Leary Rolfe A.
Published: July 2007

Historically, forest growth was estimated using a normal or near-normal yield table as a density standard, and a relative density change equation to estimate approach to the standard. Although normal yield tables have come under intense criticism, critics have generally ignored the relative density change equation. If a yield table captures the "true" relations between volume, age, and site for a species, the relative density change equation can be a simple function of initial relative density and age. If a yield table does not capture the true relations between volume, site, and age, the inadequacy can be overcome by developing more complex relative density change equations, i.e., by transferring representation burden to the change equation. Introduced in the present paper is the concept of an identity yield table (all entries are one), wherein the entire burden of representing the relations between volume, site, and age is transferred from a density standard to a relative density change equation. Modern whole stand (net) growth models are equivalent to historical relative density change equations based on identity yield tables. The conjecture of a continuum of methods to estimate growth from near-normal to empirical to identity yield tables, each with an appropriate relative density change equation, and each equally accurate, is tested on Wisconsin jack pine (Pinusbanksiana Lamb.). The empirical yield table and its relative density change equation were more biased than near-normal and identity-based projection systems.
Soil chemistry changes after 27 years under four tree species in southern Ontario
Authors: France Elizabeth Anne , Binkley Dan , Valentine David
Published: July 2007

not available
White spruce artificial regeneration options on river floodplains in interior Alaska
Authors: Youngblood Andrew P. , Zasada John C.
Published: July 2007

Reforestation options for artificial regeneration of white spruce (Piceaglauca (Moench) Voss) were tested on three floodplain sites near Fairbanks, Alaska. Survival of containerized seedlings after outplanting was above 96%, regardless of harvest cutting method or mechanical site preparation, and declined little between the third and fifth growing seasons. Establishment and survival after direct seeding on seed spots was more variable and differed by harvest cutting method, by type of site preparation, and by the use of plastic seed shelters for seedling protection. Maximum terminal leader growth, seedling total height, and basal diameter were found on planted seedlings in clear-cut units on the better site. In clear-cut units prepared by blading on one site, basal diameter of seedlings five seasons after outplanting was almost 50% more than on similar surfaces in shelterwood units. Planted seedlings on unscarified surfaces and in small scalped patches generally had similar basal diameters. Results suggested that similar interior Alaska floodplain forests of white spruce can be successfully regenerated by using the clear-cutting harvest method and planting nursery-reared seedlings without mechanical site preparation.
Multiple-trait selection in jack pine
Authors: Adams G. W. , Morgenstern E. K.
Published: July 2007

Open-pollinated jack pine (Pinusbanksiana Lamb.) families were evaluated at four sites in New Brunswick after seven growing seasons for height growth, crown quality, stem straightness, branch angle, and relative branch diameter. Variance and covariance components were estimated to determine heritability of traits and genetic correlations between traits. Results indicated that there is a negative genetic correlation between height growth and all other traits. Selection based on height growth alone would result in degradation of quality traits of secondary economic importance at this age. A restricted selection index approach was examined for family roguing in seedling seed orchards because of the adverse genetic relationships between traits. Such an approach may be used to hold secondary quality traits constant, although some loss in maximum potential genetic gain in height at 7 years is incurred.
Internal circulation of carbon within a tree
Authors: Hari Pertti , Nygren Pekka , Korpilahti Eeva
Published: July 2007

The internal transport of carbon dioxide by water flow has until now been omitted when interpreting measurements of photosynthesis and respiration. Theoretical and empirical analyses of the behaviour of carbon dioxide within a tree show that the consideration of dissolved carbon transportation may be important when estimating the respiration rate, but not so important when considering photosynthetic production.
Response of western hemlock (Tsugaheterophylla) and early huckleberry (Vacciniumovalifolium) seedlings to forest windthrow
Authors: Alaback Paul B. , Tappeiner II John C.
Published: July 2007

Seedlings of western hemlock (Tsugaheterophylla (Raf.) Sarg.) and early huckleberry (Vacciniumovalifolium Smith) were studied for 5 years following windthrow in a dense 45-year-old forest to better understand the contrasting reproductive and growth stategies of woody shrubs and trees to small natural disturbances in temperate rain forest environments. Seedlings of both species responded to the disturbance with increased growth and increased recruitment. Tsuga seedling establishment and Vaccinium seedling density increased after the disturbance. Tsuga height growth, number of branches, and biomass were linearly related to solar radiation transmission in all 3 years. Vaccinium exhibited an exponential shoot growth pattern characterized by an initial delay of 3–4 years, whereas Tsuga increased productivity within months of the disturbance and continued to increase its growth exponentially throughout the study. Vaccinium increased rate of branching, total biomass, and allocation of biomass to roots following the windthrow, but did not significantly increase twig elongation rates until the fourth growing season. No significant difference in soil or air temperatures was detected between the forest and open windthrown areas, but litter temperatures increased by as much as 1 °C in the windthrow during the summer. Infrequent opening of dense second-growth conifer canopies whether by thinning or by small-scale disturbances is likely to result in dense secondary canopies of shade-tolerant trees and in little understory vegetation or forage for wildlife.
Soil water content as a key factor determining the source of nitrogen (NH4+ or NO3−) absorbed by Douglas-fir (Pseudotsugamenziesii) and the pattern of rhizosphere pH along its roots
Authors: Gijsman Arjan J.
Published: July 2007

Pseudotsugamenziesii (Mirb.) Franco was grown on an acid sandy soil [Formula: see text], fertilized with ammonium nitrate as the nitrogen source (50 and 150 kg N•ha−1), and maintained at two soil water levels. At both nitrogen levels, ammonium uptake was much higher in the wet soil than in the dry soil, whereas nitrate uptake was not affected by soil water content. From calculation of the nitrogen supply at the root surface, it was concluded that P. menziesii preferentially took up ammonium. Under dry soil conditions, movement of ammonium in the soil was impeded, so that the ammonium preference could not manifest itself; thus a large part of the nitrogen absorbed was in the nitrate form. Proton excretion per unit organic nitrogen formed was greater in the wet soil than in the dry soil owing to a larger ammonium contribution to total nitrogen uptake. In all treatments, the rhizosphere at the root tip was more alkaline than the bulk soil, whereas along the older root zones, acidification of the rhizosphere occurred. The strongest alkalization at the root tip occurred in the dry soil. Analysis of the rhizosphere pH pattern with a simulation model on proton transport in the soil showed that the results could only be explained by a gradual transition from OH− excretion at the root tip to H+ excretion along the older root zones. Soil water content was an important factor in determining rhizosphere pH. By extrapolating the results to forest conditions, it was determined that rhizosphere acidification may occur when the nitrification rate is low and the soil is not too dry.
The reliability of tree crown position classification
Authors: Nicholas N. S. , Gregoire T. G. , Zedaker S. M.
Published: July 2007

Traditionally, forest crown position is classified into one of four categories: dominant, codominant, intermediate, and suppressed. The crown definitions have two primary components: a tree's stature relative to the stand's canopy level and the amount and type of light received by its crown. While this classification is meant primarily for even-aged, single level canopy stands, it is applied widely to uneven-aged stands and to those with multilevel canopies. The objective of this study was to examine the repeatability of estimating crown position in a variety of stands in the southern Appalachian spruce–fir forest. We found that crown position was difficult to similarly reclassify on the second visit in uneven-aged stands. Distinguishing a dominant from a codominant crown resulted in the lowest remeasurement proportion of agreement. We propose that the canopy position definitions be clarified and suggest an alternate system of crown classification.
Comparison of centroid and paracone estimates of tree volume
Authors: Wiant Jr. Harry V. , Wood Geoffrey B. , Forslund Robert R.
Published: July 2007

The use of the centroid and paracone methods for deriving the volume of 957 sample trees from four data sets was compared. The four data sets were as follows: Australian radiata pine (Pinusradiata D. Don) (114 trees); six species of Australian commercial hardwoods (140 trees); and two sets of Appalachian hardwoods, one comprising four species (538 trees) and the other 13 species (165 trees). Comparable accuracies of prediction were achieved with both methods, although the paracone method was slightly better for all data sets except radiata pine when predicting total volume. The similarity in the predictions was shown to be a direct result of the similarity in the total volume equations of the two methods. The centroid method consistently predicted merchantable volumes better than the paracone method, which had a tendency to give poorer estimates for smaller stems as the merchantable height decreased.
Inheritance of chloroplast and mitochondrial DNA in incense-cedar (Calocedrusdecurrens)
Authors: Neale David B. , Marshall Kimberly A. , Harry David E.
Published: July 2007

Paternal inheritance of chloroplast and mitochondrial DNA in incense-cedar (Calocedrusdecurrens (Torr.) Florin (Cupressaceae)) controlled crosses was demonstrated using restriction fragment length polymorphisms. The only other plant species for which paternal inheritance of both organelle genomes has been reported is Sequoiasempervirens (D. Don) Endl., a member of the family Taxodiaceae, which is thought to be closely related to the Cupressaceae. These taxa differ from the family Pinaceae, where chloroplast DNA is predominately paternally inherited and mitochondrial DNA is maternally inherited.
The influence of floral bud phenology on the potential mating system of a wind-pollinated Douglas-fir orchard
Authors: Copes Donald L. , Sniezko Richard A.
Published: July 2007

Reproductive bud phenology from 1983 through 1989 limited potential outcross efficiency to a maximum of 58 to 87%, in a Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) clonal orchard near Monmouth, Oregon. Potential outcross efficiency was calculated for 20 clones from dates of male and female bud opening and pollination mechanism information. Cool weather before bud opening of the earliest clones delayed and compressed the breeding period and resulted in a greater percentage of trees having synchronous periods of pollen release and receptive seed strobili. Length of breeding season among years averaged 20 days and ranged from 16 to 27 days. Differences in phenology significantly impacted the breeding system because the overall breeding period of the orchard clones exceeded the 8-day receptive period of individual clones by two or three times and often prohibited or limited potential outcrossing between the earliest and latest clones. Outcrossing was greatest in clones with intermediate phenology and least in the earliest clones. The breeding system appears to be an almost continuous series of overlapping breeding subpopulations. Each year's breeding subpopulations were different from those of other years because of large shifts in rank order of bud opening by 10 to 20% of the clones and because of great differences in the length of breeding season. Average temperature during March was linearly associated with time of floral bud opening. Geneticists may be able to use average temperature of the 4-week periods prior to opening of the earliest floral buds as a tool to identify seed crops formed during years with compressed breeding seasons. Such seed crops have potential of being more diverse than do seed crops produced during years with extended breeding seasons. Use of procedures in this report will allow tree-improvement workers to calculate the maximum outcross efficiency of each seed crop produced by their orchards.
Genetic control of wood density profile in young Douglas-fir
Authors: Loo-Dinkins J. A. , Gonzalez J. S.
Published: July 2007

The relative density profile from pith to bark was examined in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stems at 1.3, 0.7, and 0.4 m above the ground. The trees represented 22 half-sib families growing at two progeny test locations. The objective was to evaluate the reliability of wood samples taken from below breast height (1.3 m) for selection for relative density in young coastal Douglas-fir progeny tests. The relative density profile appeared to be different for the first 6 or 7 years from the pith at the different sampling heights, but the difference decreased with cambial age. Genetic correlation estimates were sufficiently high to indicate identical genetic control at the three sampling heights, but heritability estimates were higher at 1.3 and 0.7 m than at 0.4 m. Sampling at 0.7 m is as effective as at 1.3 m. This allows reliable selection 1 to 2 years earlier than by sampling at 1.3 m.
Growth and ectomycorrhiza formation of container-grown red oak seedlings as a function of nitrogen fertilization and inoculum type of Laccariabicolor
Authors: Gagnon J. , Langlois C. G. , Garbaye J.
Published: July 2007

Containerized red oak (Quercusrubra L.) seedlings were inoculated at the time of sowing with Laccariabicolor (Maire) Orton using two methods to compare the efficiency of two inoculum types: a mycelial suspension (Ecot-Sol®101) produced by Rhizotec Laboratories Inc. and calcium alginate beads containing this mycelial suspension. Red oak seedlings were also grown for 19 weeks in a peat moss – vermiculite substrate under three levels of N fertilization (100, 120, and 140 mg/seedling per season) to determine the N level that maximizes the ectomycorrhizae formation and growth of seedlings. After 19 weeks in the greenhouse, seedlings inoculated with liquid inoculum had significantly more mycorrhizae than both those inoculated with beads and controls, regardless of the N level. For any of the N levels, liquid-inoculated seedlings had significantly lower shoot height, root-collar diameter, and dry weights (shoot, root, and total) than both those inoculated with beads and the controls, whereas there were no significant differences for any growth parameters between the bead and control treatments. For the three inoculum treatments, root and total dry weights of seedlings fertilized with 100 mg N were significantly lower than those of seedlings that received both 120 and 140 mg N, whereas shoot height, root-collar diameter, and shoot:root ratio of seedlings did not differ significantly between any of the three N levels. After 19 weeks, seedlings inoculated with liquid inoculum had significantly greater N and P concentrations (%) and contents (mg/seedling) than those inoculated with beads only at the 140 mg N level. Analyses show that seedling concentrations of 1.2% N and 0.1% P and substrate fertility of 25 ppm N and 30 ppm P would be appropriate to maintain the ectomycorrhizal association Q. rubra – L. bicolor.
Effect of tree roots on a shear zone: modeling reinforced shear stress
Authors: Abe Kazutoki , Ziemer Robert R.
Published: July 2007

Tree roots provide important soil reinforcement that improves the stability of hillslopes. After trees are cut and roots begin to decay, the frequency of slope failures can increase. To more fully understand the mechanics of how tree roots reinforce soil, fine sandy soil containing pine roots was placed in a large shear box in horizontal layers and sheared across a vertical plane. The shapes of the deformed roots in the sheared soil were explained satisfactorily by an equation that had been developed to model the deformed shape of artificial reinforcement elements, such as wood dowels, parachute cord, Bungy cord, and aluminum rods. Root deformation in sheared soil is influenced by the diameter and concentration of roots. A model is proposed that uses root strain to estimate the shear stress of soil reinforced by roots. The shear resistance measured from the shear tests compared quite well with the model simulation.
Characteristics of shortwave and longwave irradiances under a Douglas-fir forest stand
Authors: Black T. Andrew , Chen Jing-Ming , Lee Xuhui , Sagar Robert M.
Published: July 2007

Measurements of the spatial mean values of global irradiance, photosynthetic photon flux density, and the downward longwave irradiance under a 26-year-old, second-growth Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forest canopy on a 26° south-facing slope were made with a tramway system, which scanned a 20-m transect in 12 min. The diffuse solar irradiance under the canopy was measured with a stationary pyranometer equipped with a shadow band. The extinction coefficients for the direct, global, and photon components were derived as functions of the solar incident angle over the range of 15° to 85°. The extinction coefficient for the diffuse radiation was found to correlate well with the ratio of the direct to diffuse irradiance above the canopy. Complete diurnal cycles of the downward longwave irradiance were simulated with a simple model based on the air temperature inside the stand. Analyses of the measurements of all the shortwave and longwave components were made using an effective leaf area index, which was derived from the measurements of the direct irradiance above and below the stand. It was found that the distribution of the leaf inclination angle of a Douglas-fir canopy has strong planophile characteristics, and that in the case of a forest stand on a slope, it is critical to obtain the characteristics of the light transmission through the canopy over the entire incident angle range before effective leaf area index is calculated. Warren Wilson's 57.5° approximation did not hold for the Douglas-fir canopy, which had distinct foliage clumping features.
The role of phenols in sprouting and wood decay of birches
Authors: Kauppi A. , Paukkonen K. , Tela H-L.
Published: July 2007

Changes in the total phenol content after coppicing of Betulapubescens Ehrh. were studied in the stumps, basal buds at different stages of growth, and sprouts of various ages to determine the role of phenols in sprouting. The phenol content of the wood at the cut surface of stumps had clearly decreased 24 h after cutting, and another apparent decrease occurred about 2 weeks later, when the suppressed buds on the stump started developing. High phenol levels were maintained the longest in the light wood of the inner parts of the stump, but remained relatively low in the brown, mycelium-containing wood. Total phenol content in the dormant basal buds was highest at the beginning, over 9% of dry weight, but rapidly fell during the bursting of buds and further growth in the sprouts. Total phenol content declined still further in the stumps, sprouts, and seedlings with age. Seasonal changes in phenol content were found in seedlings of both B. pubescens and Betulapendula Roth, with the highest levels occurring in September and March. In general, total phenol content seems to be highest in young, healthy but inactive tissues. In contrast with previous studies, injury was found to decrease total phenol content in the stumps of birches. Development of the basal buds into sprouts is inhibited by phenols, so felling is a precondition for sprouting, as it leads to a decline in the phenol content. On the other hand, a decrease in phenols in the stump seems to diminish sprouting by predisposing it to wood-rotting fungi.
Stability of juvenile wood specific gravity of loblolly pine in diverse geographic areas
Authors: Jett J. B. , McKeand S. E. , Weir R. J.
Published: July 2007

The stability of wood specific gravity for 12-year-old loblolly pine (Pinustaeda L.) was evaluated for 18 open-pollinated families and four bulked seed lots representing provenances from the eastern shore of Maryland; Marion County, Florida; Gulf Hammock, Florida; and Livingston Parish, Louisiana. Wood samples were collected from seven plantings chosen to provide a north–south and east–west sample distribution essentially encompassing an area spanning the natural range of loblolly pine. There was significant genotype × environment interaction, and 4 of the 18 families were classified as unstable for specific gravity. These four families accounted for 49.5% of the genotype × environment interaction sum of squares. However, the loss in potential gain in a breeding program for specific gravity due to the presence of a significant genotype × environment interaction was estimated to be only 1%. Loblolly pine from the Florida provenances and from the widely planted Livingston Parish provenance consistently displayed low specific gravity and ranked at or near the bottom at all test locations, including the southernmost plantings.
Paired-tree study suggests 20-year recurrent slash pine blight
Authors: Deusen Paul C. Van , Snow Glenn A.
Published: July 2007

In the late winter of 1988, pairs of slash pine (Pinuselliottii Engelm.) trees were chosen and marked on the Harrison Experimental Forest in Gulfport, Mississippi. One tree of each pair had a blight and the associated fungi Lophodermellacerina Darker on all mature needles, while the other tree had healthy needles. The blight recurred on the same study trees in 1989 and 1990. Analysis of tree cores shows that the blighted member of each pair has had less radial growth than the clean (nonblighted) pair member since about 1971, when a severe needle blight occurred throughout the slash pine region. It appears that the needle blight is causing growth loss and possibly a genetic narrowing of the slash pine resource. The evidence suggests that the most severe occurrence of the blight is near metropolitan areas of the Gulf Coast.
The regrowth production and allocation of Salixarbusculoides in three growing seasons following right-of-way clearing
Authors: Grosbois T. De , Kershaw G. P. , Eyton J. R.
Published: July 2007

A homogeneous 4.3-ha area of black spruce (Piceamariana (Mill.) B.S.P.) forest located 10 km north of Fort Norman, Northwest Territories, was selected for this study. A 25 m wide corridor was cleared in the spring of 1985 to simulate a transport corridor (e.g., winter road, seismic line, or pipeline). Salixarbusculoides Anderss., the dominant erect deciduous shrub found in this area, was monitored for three growing seasons after canopy removal. Regrown shrubs on the cleared right-of-way were compared with undisturbed shrubs in an adjacent black spruce stand, which served as a control. Salixarbusculoides has an excellent propensity for natural recovery from clear-cutting through vegetative regeneration. Regrown right-of-way shrubs attained total dry weights equal to those of control shrubs by the second growing season. High rates of aboveground biomass production, which were most pronounced in the second growing season of recovery, occurred following clearing. This increased production was primarily stem growth, as leaf production in regrown shrubs was never significantly greater than leaf production in control shrubs over the 3-year period. Shrub ground cover and leaf density both increased for regrown shrubs, as leaf biomass relative to both the area of ground covered and the shrub canopy volume was higher for right-of-way shrubs in all 3 years. This suggests that over the period of the study, the shading and gas-exchange capabilities per unit area of ground of right-of-way shrubs equalled or exceeded those of undisturbed shrubs. In this area where thaw-susceptible permafrost occurs, both characteristics of resprouting shrubs are desirable in maintenance of right-of-way integrity.
Time trends in inheritance and projected efficiencies of early selection in a large 17-year-old progeny test of Pinusradiata
Authors: King J. N. , Burdon R. D.
Published: July 2007

In an open-pollinated progeny trial of Pinusradiata D. Don, stem diameter assessments were cross-referenced for 410 families for ages 5, 10, and 17 years from planting. Also cross-referenced were Cyclaneusma needle cast (CYCLA) and wood density (PILO) measured by Pilodyn needle penetration. Estimated narrow-sense heritability for stem diameter declined mildly from 0.34 at age 5 to 0.25 at age 17. Estimated heritability of family means, however, only declined from 0.59 to 0.55. CYCLA and PILO gave, respectively, narrow-sense heritability estimates of 0.32 and 0.40, with repeatabilities of family means of 0.57 and 0.67. The genetic age-age correlations for stem diameter were all positive and somewhat higher than phenotypic (family-mean) age–age correlations. Such correlations indicated comparable or slightly slower rank changes among progeny families than had been reported previously for diameter, basal area, or stem volume in P. radiata and Pinustaeda L., but faster rank changes than the literature reports for tree height. A considerable contribution of CYCLA to rank changes in stem diameter was evident from path coefficients and partial correlations. PILO made no evident contribution to rank changes. Predicted gains for stem diameter at age 17 were almost maximal using year-10 data, while using CYCLA as an auxiliary selection criterion enhanced expected gain, particularly with selection at year 5. Predicted gains for stem diameter, with age–age correlations extrapolated according to the Lambeth relationship, indicated maximal gains per annum with selection at 7–8 years for rotations of 25–30 years.
Aerated water soak increases red oak seed germination and seedling emergence
Authors: Struve Daniel K. , Dress Martin F. , Bennett Mark A.
Published: July 2007

Red oak (Quercusrubra L.) acorns were collected from three trees in September, placed in plastic bags, and held at 2 °C for 150 days. Acorns were given 0-, 10-, or 14-day aerated water soaks before germination tests were conducted. Acorns from two trees, given a 14-day soak, had significantly higher germination capacity and uniformity than untreated acorns. In another test, acorns were given a 10-day aerated water soak treatment and returned to 2 °C for 30 and 60 days. After 30 days, treated acorns had superior germination compared with untreated acorns. After 60 days, there were no significant differences in germination between treated and untreated acorns. In a greenhouse study, acorns given an aerated water soak had higher shoot-emergence capacity than untreated acorns. However, the aerated water soak treatment did not increase seedling efficiency, the ratio between the number of plantable seedlings and the number of seeds sown.
Ozone decreases spring root growth and root carbohydrate content in ponderosa pine the year following exposure
Authors: Andersen Christian P. , Hogsett William E. , Wessling Rose , Plocher Milton
Published: July 2007

Storage carbohydrates are extremely important for new shoot and root development following dormancy or during periods of high stress. The hypothesis that ozone decreases carbohydrate storage and decreases new root growth during the year following exposure was investigated. Ponderosa pine seedlings (Pinusponderosa Dougl. ex Laws.) exposed to ozone in 1989 were harvested prior to shoot elongation (nongrowing seedlings) and following a root growth test (growing seedlings) in the spring of 1990 to evaluate starch and soluble sugar concentrations. Seedlings exposed to the highest ozone level had 34% less lateral root biomass and 65% less new root biomass the following spring. Exposure to 122 and 169 ppm-h (sum of hourly means, 24 h/day, over the exposure period) during the 1989 growing season resulted in significant decreases of carbohydrate pools examined in both nongrowing and growing seedlings the following spring. Starch concentrations were most affected: at the highest ozone level, there were decreases of 43 and 44% in coarse and fine roots, respectively, of nongrowing seedlings, and 50, 65, and 62% in coarse, fine, and new roots, respectively, of growing seedlings. The results suggest that (i) ponderosa pine seedlings exposed to 122 and 169 ppm-h ozone for one season have significantly less root starch reserves available just prior to and during bud break the following year and (ii) spring root growth is decreased following ozone exposure. The carry-over effects of ozone stress may be important in long-lived perennial species that are annually subjected to ozone.
Resistance to western gall rust in artificially inoculated ponderosa pine
Authors: Hoff R. J.
Published: July 2007

Seedlings from 80 open-pollinated families of ponderosa pine (Pinusponderosa Laws.) were inoculated with western gall rust (Endocronartiumharknessii (J.P. Moore) Y. Hiratsuka) at the beginning of their 2nd year of growth. The overall infection level was 41 %, with a family heritability of 0.76. Several resistance responses were evident, heritabilities of which ranged from moderate to high; i.e., for seedlings with no symptoms, the heritability value was 0.60, while for trees with bark reactions that prevented gall formation, the heritability value was 0.71. There were three such types of bark reactions, for which heritability values were 0.36, 0.58, and 0.60. Heritability values of 0.38, 0.41, and 0.45 were found for trees with dead galls, rust-killed trees, and rate of gall appearance, respectively. Resistance of ponderosa pine to western gall rust is not only high but highly variable and exhibits a rich assortment of resistance reactions that probably account for the low level of gall-rust damage. The findings emphasize the importance of maintaining resistance in ponderosa pine tree-improvement programs.
Dew on reindeer lichen
Authors: Péch Gyula
Published: July 2007

Four reindeer lichen (Cladinarangiferina (L.) Nyl) samples were placed near ground level in the open at a meteorological station where dew and other meteorological parameters were measured. One sample was covered occasionally from sunset to sunrise to prevent dew and to evaluate moisture gain due to wetting by atmospheric vapour alone. Mass measurements were done day and night following a set schedule. At the conclusion of the field program the samples were oven-dried and all weight measurements were converted to moisture contents. The results showed that a simple linear relationship adequately describes the overnight rise of lichen moisture caused by dew, and that atmospheric vapour alone, on nights without rain or condensation, can raise lichen moisture by 15%. Further, the results confirmed that nocturnal moisture gains by either dew or atmospheric vapour dissipate on subsequent clear mornings by noon. These findings suggest that at locations where humidity is measured at night and dew may be assessed visually in the morning, one can estimate both the 06:00 maximum moisture content of the lichen and, on subsequent clear mornings, the hourly rate of its drying.
Application of Härtel's turbidity test across Europe
Authors: Cape J. N. , Vogt T. C.
Published: July 2007

The history and development of Härtel's turbidity test ("Trübungstest") for investigating the effects of sulphur dioxide on conifer needles are briefly reviewed. The turbidity test was applied to samples of Norway spruce (Piceaabies (L.) Karst.) and Scots pine (Pinussylvestris L.) needles from 13 sites in western Europe, from southwestern Germany to northeastern Scotland. Turbidity and electrical conductivity of the needle extracts were measured on duplicate samples of current-year, 1-year-old, and 2-year-old needles. The greatest differences among sites were observed for 2-year-old needles, but these differences were not related to needle sulphur content, nor to exposure to sulphur dioxide. The largest values were from British sites, and the smallest were from Dutch sites, with German sites intermediate. Turbidity values for both tree species were positively correlated (p < 0.01) with electrical conductivity of extracts, amounts of leaf surface dust, and total foliar calcium and magnesium; they were negatively correlated with amounts of chloroform-extractable wax and the acidity of macerated needles. Turbidity values for 2-year-old Norway spruce needles and conductivity values for 2-year old Scots pine needles were significantly greater (p < 0.05) within sites for trees with visible decline symptoms (needle loss and discoloration). The large differences in turbidity values among sites suggest that the turbidity test provides a simple method for characterizing conifer needles, and that a better understanding of the basis of the test may lead to a better understanding of the physiological and biochemical status of conifer foliage.
National site-index and height-growth curves for white spruce growing in natural stands in Canada
Authors: Alemdag I. S.
Published: July 2007

Based on stem analyses, national site-index equations and height-growth equations for white spruce (Piceaglauca (Moench) Voss) were developed covering an area from the Yukon to Newfoundland. The objective was to construct a single set of curves for each relationship by combining all regions, instead of separate curves for individual provinces or regions. The results of these tests indicated that the objective could be reached without any significant loss of accuracy. In developing the equations a modified form of the Chapman–Richards function was employed, and results are presented in tabular and graphical forms.
Shoot-length frequencies in black birch (Betula lenta)
Authors: Wilson Brayton F.
Published: July 2007

Lengths of all parent and current shoots were measured on three 8- to 10-year-old black birch (Betulalenta L.) trees with branches <8 years old. Older branches had more short shoots (<1 cm long) and shorter long shoots (>2 cm long) than younger branches. Parent long shoots produced three to nine basal short shoots. Observations on short-shoot production were consistent with the hypothesis that only buds with adequate nutrition formed long shoots. Three growth rules were developed for a model that simulated individual branch growth: (i) a regression predicting lateral shoot number from each parent shoot length; (ii) probabilities for the number of short shoots produced by a parent shoot based on the total number of current shoots produced per parent shoot; (iii) a regression predicting current shoot length from parent shoot length, current shoot position (longest to shortest), branch age, and main-axis elongation in the current and previous year. Simulations of 81 branches using these rules predicted shoot numbers and total shoot lengths close to those of the actual branches (R2 = 0.73–0.84).
Sensitivity of leaf gas exchange to atmospheric drought, soil drought, and water-use efficiency in some Mediterranean Abies species
Authors: Guehl J. M. , Aussenac G. , Bouachrine J. , Zimmermann R. , Pennes J. M. , Ferhi A. , Grieu P.
Published: July 2007

The responses of CO2 assimilation rate (A), transpiration rate (E), and leaf conductance (g) to increasing leaf to air water vapor concentration difference (ΔW) were investigated (i) using excised shoots from mature trees of Abiesalba, Abiescephalonica, Abiesmarocana, and Abiesnordmanniana and (ii) in situ on a mature tree of Abiesbornmulleriana. Gas-exchange responses to increasing soil drought were also studied in plants of A. bornmulleriana, A. cephalonica, and Cedrusatlantica. Stable carbon isotope composition measurements were carried out on annual growth rings of A. bornmulleriana to estimate the time-integrated values of the ratio of intercellular leaf (Ci) to ambient (Ca) CO2 concentration. Increasing ΔW around the shoots reduced A and g in such a way that either Ci remained constant or its decrease was not pronounced enough for the changes in A to be accounted for by changes in g only. This suggests a direct effect of ΔW on photosynthesis. The different Abies species showed clear differences in water-use efficiency. Abiescephalonica and A. marocana had lower water costs of CO2 assimilation (E/A) than A. nordmanniana and A. alba. It has also been shown that A. cephalonica and A. marocana are characterized by an optimal stomatal control of leaf gas exchange. Stomata closed very rapidly in A. bornmulleriana in response to water supply being withheld, even prior to there being any important decrease in leaf predawn water potential. The stomatal response in C. atlantica was more gradual. In A. bornmulleriana, drought adaptation appears to be linked to the ability to avoid internal water stress, whereas drought adaptation in C. atlantica involves the ability to tolerate internal water stress. The high stomatal sensitivity mA. bornmulleriana is also supported by the isotopic carbon composition data, as shown by the substantial interannual variations in the estimates of Ci/Ca, ranging from 0.48 for the dryest years to 0.61 for the rainy years.
Coarse woody debris in an old-growth deciduous forest on the Cumberland Plateau, southeastern Kentucky
Authors: Muller Robert N. , Liu Yan
Published: July 2007

Volume and mass of coarse woody debris (> 20 cm diameter) in an old-growth forest on the Cumberland Plateau in southeastern Kentucky averaged 66.3 m3/ha and 21.8 Mg/ha, respectively. Coarse woody debris was patchily distributed among 80 sample plots (0.04 ha each), with 10 plots containing 39% of the total mass. Coarse woody debris mass was inversely, although not strongly, related to plot basal area. While 23 species contributed to the accumulation of coarse woody debris, five accounted for 72% of the total mass. These included Quercusprinus L. (25% of the total), Fagusgrandifolia L. (16%), Quercusalba L. (12%), Castaneadentata (Marsh.) Borkh. (11%), and Quercusvelutina Lam. (9%). The few studies of coarse woody debris in old-growth deciduous forests of North America suggest a regional pattern of accumulation correlated with temperature. In warmer regions, old-growth deciduous forests accumulate a mass in the range of 22–32 Mg/ha, while in cooler ecosystems, coarse woody debris ranges from 34 to 49 Mg/ha.
An evaluation of the water balance technique for the estimation of evapotranspiration for a mixed forest
Authors: Papakyriakou T. N. , McCaughey J. H.
Published: July 2007

In the summer of 1987 a detailed field experiment was conducted at the Petawawa National Forestry Institute at Chalk River, Ontario, to evaluate the performance of the water balance technique for the estimation of evapotranspiration. Bowen ratio – energy balance estimates of evapotranspiration, available over a portion of an intensive measurement period, provided an independent check on the water balance estimates. The daily totals of evapotranspiration were on average 1% less than the Bowen ratio – energy balance estimate. The length of time required to maintain the evapotranspiration estimates below a 10% level of uncertainty using the water balance technique is 13 days. The lowest average daily percent probable error is obtained for an integration period with (i) a minimum number of precipitation events, (ii) a large number of days, and (iii) a high evapotranspiration rate.
Aire minimum d'échantillonnage ou nombre de points de prisme nécessaires pour établir la structure d'un peuplement inéquienne
Authors: Grenier Yvon , Blais Louis , Lavoie Éric
Published: July 2007

A complete forest survey was conducted on an 18-ha maple stand mixed with yellow birch and American beech. Diameter at breast height of all merchantable stems was recorded. The location of all those stems was reported on a grid system to allow subsequent simulation of sampling by varying the size of rectangular sample plots. Prism sampling was also carried out in the same area. Statistical testing (χ2) were used to verify if randomized sampling gave the same diameter distribution as the original stand. Both sampling methods were adequate. Rectangular sample plots, 2 m wide by 5000 m long, representing an area of 10 000 m2 (i.e., 5.6% of the original stand) or 36-point sample (2 points per hectare) gave a good representation of the entire population at a probability level of 90%, with a confidence level of α = 0.05. For both sampling methods, sampling units must be scattered as much as possible in the forest area to be surveyed.
Elevation-mediated effects of balsam woolly adelgid on southern Appalachian spruce–fir forests
Authors: Dale V. H. , Gardner R. H. , DeAngelis D. L. , Eagar C. C. , Webb J. W.
Published: July 2007

The pattern of distribution of endemic Fraser fir (Abiesfraseri (Pursh) Poir.) in the southern Appalachian Mountains is being affected by infestation of the exotic balsam woolly adelgid (BWA) (Adelgespiceae (Ratz.)). BWA kill mature fir trees in about 3–9 years after initial infestation. Prediction of the effects of BWA in a forest region requires an assessment of (i) the population dynamics of the BWA and the fir, (ii) the prevailing physical conditions that affect the spread of BWA, and (iii) the subsequent pattern of fir mortality. This paper predicts the patterns of fir mortality and recovery on an elevation gradient by using a population model with site-specific environmental conditions and ecological interactions. The model shows that temperature range and amplitude, which affect the survival and development rates of BWA, can have an indirect influence on the spatial pattern of living trees. The model results suggest that persistence of both species, with oscillations in numbers over time and space, is probable.
Forest understory plants as predictors of lodgepole pine and white spruce site quality in west-central Alberta
Authors: Strong W. L , Pluth D. J. , Roi G. H. La , Corns I. G. W.
Published: July 2007

The feasibility was explored of using cover estimates of a few understory species with high indicator value, rather than total species lists, to evaluate site quality for lodgepole pine (Pinuscontorta Loudon var. latifolia Engelm.) and white spruce (Piceaglauca (Moench) Voss). Analysis of 112 vascular and 7 nonvascular understory plant species from 211 lodgepole pine and white spruce dominated forests revealed that 39 and 30 of these species had significantly different percent cover among site-index classes for stem-analyzed pine and spruce, respectively. Individual species cover values were then used in simple and multiple linear regression equations to predict the site index (at 70 years) for pine and spruce in 60–90 year and 91–160 year stand age subsets. Equations for pine based on understory species cover explained 38% of the variance in site index in younger stands and 59% in older stands; comparable maxima for spruce were 42% in younger stands and 50% in older stands. These percentages may be too low for stand-alone predictions of site index. Several possible sources of error may cause the low explained variance, including crude field estimates and seasonal variations of cover. Many of these potential sources of error could be minimized, allowing better prediction of forest site quality.