bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenolic character of sequential solvent extracts from western hemlock and white spruce barks
Authors: Fraser H. S. , Swan E. P.
Published: April 2011

Barks from two important British Columbia conifers, white spruce (Piceaglauca (Moench) Voss) and western hemlock (Tsugaheterophylla (Raf.) Sarg.) were extracted sequentially with solvent of increasing polarity (alcohol–benzene, alcohol, water, dilute base). High yields and good formaldehyde reaction with the hemlock–alcohol solubles and the spruce-water solubles showed promise that these will be useful in adhesive formulation. Average yield and poor reaction with formaldehyde from the base-soluble phenolic acids showed that these should be avoided in adhesive formulations. The yields of the extractives are given and the phenolic character, and thus possible adhesive reactivity of these bark extractives, is discussed.Variables studied were inner and outer bark, and geographical location; formaldehyde number, phenolic hydroxyl group content, and differential scanning calorimetry were used to assess adhesive reactivity.
The occurrence of bisexual strobiles on black spruce (Piceamariana (Mill.) B.S.P.) in the forest-tundra ecotone: Keewatin, Northwest Territories
Authors: Elliott Deborah L.
Published: April 2011

not available
Distribution of methyl benzimidazol-2-yl carbamate phosphate in elm: effects of chemical properties and formulation variables
Authors: Roy D. N. , Purdy J. R. , Ayyamperumal P.
Published: April 2011

The distribution of fungitoxic activity in twig samples taken from the crown of elm trees (Ulmusamericana L.) after injection with methyl benzimidazol-2-yl carbamate phosphate (MBCP) was erratic with respect to tree size and dosage. Evidence is presented which supports the view that this resulted from stoppage of flow in the xylem, probably as a result of precipitation of the free base (MBC), and was aggravated by variables associated with the fungicide and its formulation. Physiological and environmental effects were partly or completely masked. Bioassays showed that MBCP was more active than methyl benzimidazol-2-yl carbamate hydrochloride (MBCC) invitro, whereas Calixin and Meltatox were not active against Ceratocystisulmi (Buism.) below a 1000-ppm concentration. A new elm tissue culture bioassay showed that MBCP was not phytotoxic at low levels. The insecticides aldecarb, diazinon, dimethoate, Meta-Systox R, and phosphamidon were excessively phytotoxic, and thus not suitable as injectable systemic insecticides.
Comparative root system morphologies of seeded-in-place, bareroot, and container-cultured plug Sitka spruce seedlings after outplanting
Authors: Carlson W. C. , Preisig C. L. , Promnitz L. C.
Published: April 2011

Root systems of Piceasitchensis (Bong.) Carr. seedlings of natural, bareroot, and container origin were quantitatively analyzed to determine effects of seedling source on root system morphology, particularly lateral root orientation.Planted stock types were differentiated from natural seedlings on the basis of root system morphology. Container-induced effects on root system morphology were no greater than effects of bareroot cultural and planting practices. The data presented indicate that effects of culturing and planting on root system morphology are probably not severe enough to cause instability or growth retardation.
Inheritance and correlations of frost injury, growth, flowering, and cone characteristics in white spruce, Piceaglauca (Moench) Voss
Authors: Nienstaedt Hans
Published: April 2011

White spruce progenies from the Lake States (61) and from the Ottawa River Valley, Ontario (31), were tested in north-central Wisconsin. Transplants were raised in nurseries in Wisconsin and Ontario and planted in 1969 in an open field after thorough weed control. Observations in the Wisconsin nursery and in the field between 1971 and 1979 are reported. They included heights, frost damage, spring vegetative growth phenology, strobili production, and three cone characteristics. The discussion concentrates on the relationships between heights and the other measured characteristics. Frost damage proved difficult to assess. In the year of frost, damage is severe, a 50% growth reduction, and the fastest growing trees are most severely damaged. However, in environments with only occasional late spring frosts, permanent damage is negligible. Spring growth initiation was not correlated significantly with total height growth or frost damage. Breeding of late-flushing genotypes that can avoid frost damage is questionable in spite of the high heritability for flushing. Female strobili production was substantial at age 10 years, male production was not. Even so, generation turnovers of 10–15 years may be possible. The impact of fecundity on growth potential is discussed as it relates to multigeneration breeding.
The Shasta red fir forest of California
Authors: Barbour Michael G. , Woodward Roy A.
Published: April 2011

Thirty pristine Shasta red fir stands (Abiesmagnifica var. shastensis Lemmon) in the North Coast Range and in the southern Sierra Nevada of California were sampled for stand and age structure by point-quarter and quadrat methods. In most respects, the two group of stands were not significantly different. The average Shasta red fir importance value was 285, the density of individuals >45 years old and >3 cm dbh was 318 ha−1, the basal area was 58 m2 ha–1, and the canopy cover was 56%. Sapling (1–45 years old) density averaged 1636 ha−1 and seedling (<1 year old) density averaged 12 400 ha−1. Shrub and herb cover and species richness were moderately low and most species were not present in more than one stand. Stand population age structure was many aged. Generally, there was a steep decline in numbers from seedling to sapling to understory tree (45–250 years) to mature overstory tree (250–600 + years) categories, a pattern characteristic of a climax species. The average annual radial trunk increment (breast height) was 1.4 mm year−1. These Shasta red fir stands were not significantly different from Shasta or red fir (Abiesmagnifica A. Murr.) stands sampled by others throughout the state.
CO2 and water vapor exchange of Pinustaeda in relation to stomatal behavior: test of an optimization hypothesis
Authors: Fites J. A. , Teskey R. O.
Published: April 2011

Responses of CO2 and water vapor exchange to absolute humidity deficit (AHD) were measured for seedlings of Pinustaeda L. at high and low irradiance in the laboratory. Diurnal patterns of CO2 and water vapor exchange of P. taeda seedlings and trees were monitored in the field. Stomatal behavior was evaluated in relation to a recent hypothesis of "optimal" stomatal behavior, in which changes in stomatal conductance in response to environmental variation are such that water loss is minimized for a given amount of carbon gain. That is, when stomatal behavior is "optimal," the ratio (gain ratio) of the sensitivities of transpiration and net photosynthesis to changes in stomatal conductance [Formula: see text] is constant.Laboratory and field stomatal behavior generally did not conform with this hypothesis. Under controlled conditions, at high irradiance, the gain ratio increased with AHD. In the field, the gain ratio increased diurnally on most days. Increasing gain ratios were associated with increasing [Formula: see text] values but relatively uniform [Formula: see text] values. Uniform gain ratios in the field were observed on some days, associated with uniform environment, constant [Formula: see text], or varying [Formula: see text] values.
Nursery growth of conifer seedlings using fertilizers of different solubilities and application time, and their forest growth
Authors: Driessche R. van den
Published: April 2011

Douglas-fir (Pseudotsugamenziesii (Mirb.) (Franco) and white spruce (Piceaglauca) (Moench) Voss) seedlings were grown in a bare-root nursery for two growing seasons with one of four fertilizers, Osmocote (17-7-12) (OSM), ammonium phosphate (11-55-0) (AMP), ammonium sulphate (21-0-0) (AMS), or Hi-Sol (20-20-20) (HIS), each supplying one of three levels of N: 0, 210, or 350 kg N ha−1, at two different frequencies throughout the growing seasons. Fertilizers, levels, and frequencies were arranged in a factorial design and replicated in three blocks on each species. Additionally, Douglas-fir seedlings that had been grown for two seasons without fertilization were treated with the same amounts, as supplied over two seasons, of AMP, AMS, and HIS between 1 September and 20 October, as a late-season treatment. After two seasons, mean dry weight differences due to fertilizers were, for Douglas-fir seedlings: AMP > AMS > HIS = OSM, and for white spruce seedlings: AMS = AMP > HIS > OSM. Dry weight was increased by increasing level of fertilizer. Fertilization increased shoot growth compared with root growth and resulted in seedlings having more dry matter in stems and less in needles at the end of two seasons. Dry weight of 2-0 white spruce was correlated with soil pH (r2 = 0.61) NO3 (r2 = 0.57), and P (r2 = 0.34) measured in September of the first growing season, indicating that fertilizers affected growth by their influence on these factors. Measurements made at planting showed late-season fertilized Douglas-fir had higher N and P tissue concentrations than growing-season fertilized trees. On average late-season fertilized trees had 6% higher survival than growing-season fertilized trees after planting in the forest. Survival appeared related to needle N concentration at planting, with maximum survival occurring at about 2.1% N. Height and stem volume relative growth rates were higher for late-season fertilized trees, although growing-season fertilized trees were still 9% taller than late-season fertilized trees after three seasons in the forest. Results suggested that fertilizer solubility was not as important for nursery growth as fertilizer composition, and its effect on soil pH, and that late-season fertilized stock might outperform growing-season fertilized stock in the forest.
Two new height models for volume estimation of lodgepole pine stands
Authors: Zakrzewski W. T. , Bella I. E.
Published: April 2011

To reduce the cost and increase the efficiency of obtaining individual tree height information required for sample plot volume estimation, two general height–diameter (H/D) regression models were developed using two-stage regression analysis and data from 96 lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) sample plots. The derived models were examined using an independent data set of 28 plots. In addition to diameter at breast height (D), these models also included two easily measurable stand parameters as independent variables: quadratic mean diameter (Dq) and the height of a tree with diameter Dq (Hq). With a practical method to estimate Hq (from up to three heights measured) and using these two new H/D models in conjunction with available regional standard volume equations (V = f (D,H)), the stand volume estimates, on the average, were 0.003% higher (SD 4.1%) for the first model and 1.081% lower (SD 4.6%) for the second model than those obtained using traditional H/D curves for each plot based on 30 or more height measurements. The new models are therefore recommended for use in height estimation of lodgepole pine trees within the range of conditions of the data. This approach may be applied to other species and regions.
Leaf area - sapwood area relations of lodgepole pine as influenced by stand density and site index
Authors: Long James N. , Smith Frederick W.
Published: April 2011

Leaf area to sapwood area ratios for a given species are believed to vary with factors such as site quality, stand density, early stand growth rates, and crown class. Based on data from 55 mature lodgepole pine trees (Pinuscontorta var. latifolia Dougl.) from 10 plots in southeastern Wyoming, we conclude that putative density and site effects on leaf area - sapwood area relations are actually a consequence of the increase in the leaf area to sapwood area ratio with increasing sapwood area. When leaf area is estimated with a nonlinear model that includes tree size and distance to the live crown, the apparent effects of stand density and site index disappear. We consider a constant ratio of leaf area and sapwood cross-sectional area to be inappropriate for the estimation of leaf area aross the range of stand conditions included in most studies of forest ecology.
Restoration of high adventitious root regeneration potential in mature Betulapapyrifera Marsh, softwood stem cuttings
Authors: Struve Daniel K. , Lineberger R. Daniel
Published: April 2011

Grafted mature (flowering) Betulapapyrifera Marsh, scions were used to investigate restoration of high adventitious root regeneration potential in softwood stem cuttings. Scion manipulation (defoliation), serial propagation (using previously rooted cuttings as stock plants), hedging (severe pruning), and micropropagation were used as possible restoration treatments. Over a 15-month period, more than 8000 softwood stem cuttings were taken for propagation. Serial propagation more than doubled (from 20 to 44%) rooting response. Rooting response of tissue cultured microcuttings resulting from adventitious shoot initiation averaged 95% for 35 clones. By comparison, rooting response of open pollinated seedling families was 87% and stem cuttings from stock plants grown from tissue cultured microcuttings averaged 75%. Variation in clonal rooting response among propagation times represented a greater source of variation than that attributed to serial propagation or clone. Scion manipulation and hedging were ineffective in increasing stem cutting rooting potential. High rooting potential in mature birch can best be restored via tissue culture.
Composite vector estimators derived by weighting inversely proportional to variance
Authors: Gregoire Timothy G. , Walters David K.
Published: April 2011

A composite estimator of the coefficient vector in a linear regression model is derived by weighting inversely proportional to variance. The resulting estimator is identical to the mixed estimator and to the single-update Kalman filter.
The effects of stand density on frequency of filled seeds and fecundity in lodgepole pine (Pinuscontorta Dougl.)
Authors: Smith Christopher C. , Hamrick J. L. , Kramer Charles L.
Published: April 2011

In lodgepole pines self- and cross-pollination initiate the development of seeds with equal frequency, but self-pollination results in filled seeds only 17% as frequently as cross-pollination. A study of the frequency of initiation of seed development and filled seeds in 17 stands of lodgepole pine differing in spacing and growth form of trees indicates that both the quantity of pollen produced by a tree and the density of conspecific individuals influence the frequency of filled seeds. Moreover, the positioning of a cone relative to the top and bottom or windward and leeward sides of a tree influences the frequency of filled seeds. Genetic markers used in controlled crosses indicate that cross pollen fertilizes significantly more than half the filled seeds resulting from crosses with equal mixes of self and cross pollen. The effect of density of conspecifics and growth form of trees on the frequency of filled seeds gives an adaptive basis for the facultative shift in sex ratio in lodgepole pine. It also suggests an adaptive basis for the high frequency of dioecy in wind-pollinated, woody perennials of the Great Basin Region. This relationship also has practical implications for the management of breeding systems for seed production and reforestation.
Multiplication du Thujaplicata par culture invitro de tissus juvéniles et âgés
Authors: Misson Jean-Pierre
Published: April 2011

Young fragmented stems of Thujaplicata D. Don ex Lambert were soaked in a cytokinin solution and then induced to bud on a modified Murashige and Skoog culture medium. N6-benzyIadenine and N6-(2-isopentyl)adenine both induce bud formation. N6-(2-isopentyl)adenine is preferable for subsequent lengthening of the buds. A histological study of T. plicata leaf axils showed the existence of meristematic zones or zones able to dedifferentiate after treatment with cytokinin, which demonstrated the origin of the buds obtained. Shoots rooted on a culture medium containing α-naphthalineacetic acid and N6-furfuryladenine (kinetin). The vegetative multiplication technique of juvenile tissues were used on aged clones in a rejuvenation phase. The budding obtained is similar to that of juvenile tissues. Successive soakings in cytokinin during the budding period and prior to the rooting phase resulted in a significant increase in the percentage of rooting.
Regression analysis using auxiliary information from time studies of cable yarding operations
Authors: Howard Andrew F. , Thérien Guillaume
Published: April 2011

Time studies are commonly employed in the analysis of cable yarding productivity. For a given site and system, productivity is a function of the yarding distance and the load size. Field conditions make it more difficult to sample load volume than yarding distance, which leads to substantial differences in sample size for the two variables. When multiple linear regression is used to fit equations for predicting yarding productivity to these data, many of the observations must be omitted. Two alternatives to conventional multiple linear regression that make use of the auxiliary information in the additional observations on yarding distance were compared on the basis of statistical efficiency. A mixed estimator was found to be most efficient for all yarding systems studied.
Factors influencing the induction of embryogenic and caulogenic callus from embryos of Piceaglauca and P. engelmanii
Authors: Webb D. T. , Webster F. , Flinn B. S. , Roberts D. R. , Ellis D. D.
Published: April 2011

Zygotic embryos of Piceaglauca (Moench) Voss from five half-sib seed families and P. engelmanii Parry from one half-sib family, collected on July 13 and 27 and August 24, were cultured in the presence of 2,4-dichlorophenoxyacetic acid, N6-benzyladenine, and sucrose ranging from 0.5 to 4% for the induction of embryogenic callus and the production of stable embryogenic callus lines. Embryogenic callus was induced from all three collections with all seedlots. The July 13 collection was two to four times more embryogenic than the later collections. Embryogenic callus was induced at all sucrose levels, but 4% sucrose was clearly inferior, whereas 1% was best overall. Factors that favored the induction of embryogenic callus also favored the production of stable embryogenic callus lines. There was a 40% decline in callus line establishment compared with embryogenic callus induction and some seed lots failed to yield embryogenic lines from the two later collections. The formation of caulogenic callus was promoted at 3 and 4% sucrose. Embryos from the August 24 collection were more caulogenic than those from the earlier collections.
Permeabilization of Piceaglauca protoplasts to macromolecules
Authors: Bekkaoui Faouzi , Dunstan David I.
Published: April 2011

Chemical permeabilization (polyethylene glycol, molecular weight 3350) and electropermeabilization (electroporation) treatments were applied to white spruce protoplasts to determine their effectiveness for uptake of membrane impermeable macromolecules. The two techniques have been compared using the membrane impermeable fluorescent dye calcein (molecular weight 622). The effects of varying the polyethylene glycol concentration, or the capacitance and voltage, were tested. In both techniques, the viability of protoplasts decreased after treatment compared with the controls. However, electroporation (capacitance 25 μF; voltage 300 V, 750 V•cm−1) gave better-permeabilization results (55% protoplast viability with 96% of these being fluorescent protoplasts) than the best treatment with polyethylene glycol (20%) (30% protoplast viability with 15% being fluorescent protoplasts). An investigation was made with the dye fluorescein isothiocyanate dextrans at different average molecular weights: 4000, 70 000, and 150 000. The degree of internalization by electroporation of each of these molecules did not substantially differ, though they were all low compared with calcein, which is suggestive of a limitation in permeability. The protoplasts subjected to either polyethylene glycol or electroporation treatments gave rise to callus and proembryos.
Controlling vitrification in Larixdecidua via culture media manipulation
Authors: McLaughlin J. , Karnosky D. F.
Published: April 2011

Vitrification rates obtained from our inverted embryo system were significantly decreased by lowering the cytokinin concentrations in Brown and Lawrence medium containing 10 mM L-glutamine from 10 to 1 mg/L, or by replacing 10 mM L-glutamine with equimolar concentrations of Ca(NO3)2 or by adding 1 g/L Gelrite to the normal 10 g/L Difco–Bacto agar in the culture media. In all treatments, decreased vitrification was accompanied with decreased adventitious bud production. With reduced N6-benzylaminopurine, vitrification decreased from 77 to 29%, but bud production decreased from 61 to 17 buds per explant and mortality increased from 3 to 33%. Incorporation of Ca(NO3)2 into the media decreased vitrification from 87 to 21%, but the number of adventitious buds per embryo decreased from 75 to 42. Vitreous shoots were reverted to normal development with an 81% reversion frequency and a 6% mortality rate by culturing these shoots on Gresshof and Doy medium with one-half total nitrogen. Elongation of previously vitreous shoots was best when these shoots were cultured on Gresshof and Doy medium + 0.5 mg/L N6-benzylaminopurine for 2 weeks, followed by subculture on Gresshof of and Doy medium + 10 g/L charcoal.
Biomass partitioning and nitrogen retranslocation in black spruce seedlings on competitive mixedwood sites: a bioassay study
Authors: Malik V , Timmer V R
Published: April 2011

Black spruce (Picea mariana (Mill.) BSP) seedlings were exponentially nutrient loaded by applying 3 or 6 times more fertilizer than recommended for conventional seedling production in the nursery. Loaded seedlings were similar in height and biomass to nonloaded seedlings after nursery culture, but their tissue N, P, and K content was almost twice as much as that of nonloaded seedlings. The seedlings were transplanted on intact potted substrates (bioassays) retrieved with natural vegetation from two boreal mixedwood sites and grown for one season in a greenhouse to study early- and late-season growth and nutrient dynamics, and nutrient loading and herbicide effects on N retranslocation processes. After transplanting, height and biomass growth of loaded seedlings were, respectively, 9-14% and 24-49% more than nonloaded seedlings in herbicide-treated plots, and 14-32% and 42-85% more in untreated plots, resulting in 32-39% biomass reduction in natural vegetation. The effect of nutrient loading on growth was attributed to earlier and greater biomass and N partitioning to current needles and roots that promoted N uptake (up to 20.9 ± 1.7 mg) compared with nonloaded seedlings (up to 11.8 ± 1.2 mg). Although both loading and herbicide treatments stimulated seedling growth and N uptake, N retranslocation from older to actively growing tissues was promoted by loading but reduced by herbicide treatment. The results demonstrate the high dependence of seedlings on internal nutrient reserves when planted in competitive environments, and that nutrient retranslocation is mainly driven by current growth, nutrient uptake, and internal nutrient reserves.
Positional accuracy of boundaries between clearcuts and mature forest stands delineated by means of aerial photointerpretation
Authors: Næsset Erik
Published: April 2011

Four skilled interpreters delineated 48 boundaries between mature forest stands and clear-felled or nonproductive areas using black and white and color infrared aerial photographs. The positions of the boundaries were compared with ground-truth points located along the boundaries. On average, the interpreters located the boundaries 1.22-2.44 m inside the mature forest stands. Film type, focal length, location of the boundaries within different parts of the stereo models, and the height of the trees along the boundaries did not affect the interpretations significantly. Shadows caused by the trees, which is a hinderance to ground visibility, seriously affected the interpretation. The interpreters placed the boundaries 0.62 m farther inside the mature stands for boundaries covered by shadow than for boundaries without shadows.
Competitive effects of conspecific and herbaceous (weeds) plants on growth and branch architecture of Populus xeuramericana cv. Eugenei
Authors: Marino Paul C , Gross Katherine L
Published: April 2011

The influence of tree density (2 x 3, 1 x 2, and 0.5 x 1 m) and weed control (weedy vs. weed free) on the growth and branching architecture of Populus xeuramericana cv. Eugenei was examined in an experimental plantation in southwestern Michigan, U.S.A. In the presence of weeds, poplars were shorter (p < 0.0001), had a smaller basal diameter (p < 0.0001), initiated fewer branches (p = 0.0004), and had fewer living branches (p = 0.002), shorter branches (p < 0.0001), and branches that spread outward (p < 0.0001). Increasing tree density decreased poplar height (p < 0.0001), basal diameter (p < 0.0001), branch length (p = 0.0062), and the number of living branches (p < 0.0001). At high densities, branches spread outward at their origin (p = 0.0015) and then curved sharply upward (p = 0.002). At the highest planting density there was no difference in branching in plots with and without weed control. However, poplars in the weedy treatment were smaller than those in the weed-free treatment (p < 0.0001). Our results demonstrate that poplar growth and architecture can be influenced by competitors of very different stature. Weeds, in fact, have a greater effect on growth than conspecifics. As a result, poplars grown in the presence of weeds are stunted relative to poplars grown in the absence of weeds, even at the highest tree density where the competitive effects of poplars reduced weed biomass.
Impact of timber-fee increases on British Columbia forest products companies: an economic and policy analysis
Authors: Binkley Clark S , Zhang Daowei
Published: April 2011

On 14 April 1994, the British Columbia government announced a new stumpage formula that, at then-expected product prices, increased the average charge by about $12/m3 and more than doubled the rate at which stumpage fees change when lumber prices change. Most of the increased revenues are reinvested in the forest sector by a new organization, Forest Renewal British Columbia (FRBC), created specifically for that purpose. Using standard event-study methodologies, this paper documents the net effect of the fee increases and new policy direction on British Columbia forest products companies. After controlling for firm-specific risk and the decline in the Toronto Stock Exchange that occurred at about the same time, the new stumpage policy extracted about $1.0 billion from shareholders of the firms studied, and perhaps $2.4 billion from all licencees (an amount roughly equal to the capitalized after-tax cost of the higher fees). The impact on individual firms is highly correlated with the allowable annual cut (AAC) in replaceable licenses each holds, with an average impact of about $33.3/m3 of AAC. The market appears to have discounted both the good news about offsets in impending timber-supply reductions that the creation of FRBC implies and the reductions in earnings risk that the new stumpage system provides. When added to the increased regulatory costs associated with the new provincial Forest Practice Code, the timber-fee increases appear to have fully depleted the value of holding British Columbia timber quotas.
Outlier-resistant estimators for Poisson sampling: a note
Authors: Williams Michael S , Schreuder Hans T
Published: April 2011

Poisson (3P) sampling is a commonly used method for generating estimates of timber volume. The usual estimator employed is the adjusted estimator, Y hata. The efficiency of this estimator can be greatly influenced by the presence of outliers. We formalize such a realistic situation for high-value timber estimation for which Y hata is inefficient. Here, yi approx beta xi for all but a few units in a population for which yi is large and xi very small. This situation can occur when estimating the net volume of high-value standing timber, such as that found in the Pacific Northwest region of the United States. A generalized regression estimator and an approximate Srivastava estimator are not affected by such data points. Simulations on a small population illustrate these ideas.
Spread of S and P group isolates of Heterobasidion annosum within and among Picea abies trees in central Lithuania
Authors: Vasiliauskas Rimvydas , Stenlid Jan
Published: April 2011

Spread of Heterobasidion annosum (Fr.) Bref. was investigated in a 60-year-old Norway spruce (Picea abies (L.) Karst.) stand in central Lithuania. Of the 375 trees sampled, H. annosum was isolated from 85 (22.7%). Forty nine (56.3%) of the isolates belonged to the S group and 38 (43.7%) to the P group. Among the S-group isolates, 35 genets occupied 49 trees (1.4 trees per genet on average). In the P group, 24 genets were detected in 37 trees (1.5 trees per genet on average). The largest S and P genets were 21 and 20 m in diameter, respectively. The S group spread was more extensive within stems than for the P group; mean length of the decay column for S-group isolates was 459 ± 159 cm (mean ± SD), and it was 327 ± 101 cm for P-group isolates (p = 0.0001). Average stump area affected by decay was 56 ± 15%for the S group, and 47 ± 16% for the P group (p = 0.016). This is the first published field data on intersterility group related difference in decay extension in tree stems. The S group is better adapted than the P group to growth in Norway spruce wood.
Crown structure and growth efficiency of red spruce in uneven-aged, mixed-species stands in Maine
Authors: Maguire Douglas A , Brissette John C , Gu Lianhong
Published: April 2011

Several hypotheses about the relationships among individual tree growth, tree leaf area, and relative tree size or position were tested with red spruce (Picea rubens Sarg.) growing in uneven-aged, mixed-species forests of south-central Maine, U.S.A. Based on data from 65 sample trees, predictive models were developed to (i)estimate the amount of foliage held by individual trees from sapwood cross-sectional area and (ii)define the relationship between stem volume growth and three variables: total foliage area, relative position in the stand, and the degree of past suppression. A model that included variables representing tree size (or relative social position) and degree of past suppression (live branch whorls per unit crown length) indicated that stem volume growth first increased but later decreased over leaf area when other variables were held constant. Growth efficiency declined with increasing tree leaf area, although greater height and diameter enhanced growth efficiency and greater past suppression diminished growth efficiency. The decline in growth efficiency with greater leaf area likely is attributable to one or several of the factors previously identified as contributing to growth declines in mature, even-aged stands.
Aboveground biomass partitioning and crown architecture of Eucalyptus nitens following green pruning
Authors: Pinkard E A , Beadle C L
Published: April 2011

The effects of green pruning on aboveground biomass partitioning and crown architecture were explored in a 3-year-old Eucalyptus nitens (Deane and Maiden) Maiden plantation. Responses were measured in five height zones and three foliage age classes over a 20-month period following removal of 0, 50, or 70% of the green crown length. Development of foliage in the upper crowns of 50%-pruned trees was faster and total leaf area at the end of the experiment was greater than in unpruned trees. Leaf area development of 70%-pruned trees was similar to that of unpruned trees. Larger apical leaves, with a lower specific leaf area (SLA), developed following 50% pruning. However, 70% pruning resulted in smaller leaves, and SLA increased in some crown positions. Pruning reduced branch diameter and length in the upper crowns. However, branches of 50%-pruned trees had an increased ratio of foliage to wood dry mass. These responses to green pruning may have increased the carbon-fixing capacity and the efficiency of carbon utilisation of the remaining crown. Following 50% pruning, responses were sufficient to maintain stem dry mass increment at a level similar to that of unpruned trees. However, following 70% pruning, stem and branch dry mass increment was reduced.
Canopy leaching, dry deposition, and cycling of calcium in Austrian oak stands as a function of calcium availability and distance from a lime quarry
Authors: Berger Torsten W , Glatzel Gerhard
Published: April 2011

Three Austrian oak stands were chosen along a 4-km distance gradient from a lime quarry to study effects of Ca availability both on dry deposition rates and on Ca cycling in these ecosystems. A fourth stand was used as a more regional reference site, some 30 km west of the lime quarry. Calcium bulk precipitation fluxes decreased with increasing distance from the lime quarry, contributing to major differences in available Ca along the transect over the last decades. Higher supply of Ca changed biogeochemical cycling by increasing pool sizes and fluxes of Ca in foliage, litter, throughfall, forest floor, soil, herbaceous vegetation, and soil solution. Regression analyses of net throughfall was a useful tool for separating between dry deposition and leaching of Ca. Dry deposition rates of particulate Ca declined rapidly with increasing distance from the Ca source. Leaching of Ca from the canopy declined along the gradient according to Ca content of the green foliage during the growing season. Leaching rates as a percentage of the stand's annual requirement indicated a relative shift from solid (litter) toward more solute Ca fluxes reaching the forest floor with increasing Ca availability of the stand.
Integration of somatic embryogenesis in a tree breeding programme: a case study with Picea abies
Authors: Högberg K -A , Ekberg I , Norell L , von Arnold S
Published: April 2011

Potential for integration of somatic embryogenesis in a breeding programme of Norway spruce (Picea abies (L.) Karst.), and its limitations, were investigated in a case study with an ordinary breeding population. A standard protocol was used for initiation, proliferation, and cryopreservation of embryogenic cultures; maturation of somatic embryos; and plant regeneration. This is a practical necessity when dealing with a large number of genotypes. Proliferation and maturation were identified as major constraints. Clear differences among families were seen for proliferation and for maturation. For plant regeneration, differences among cell lines within families were considerable while no significant differences were found among families. Significant differences among male parents were obtained for proliferation and maturation. Our calculations show that by using an improved standard protocol, at least one third of the genotypes can be propagated via somatic embryogenesis. No clear relationship was found between embryogenic characters of selected parents based on progenies and corresponding parental breeding values for growth and phenology characters. Three years can be gained by using somatic embryogenesis instead of cuttings in a breeding programme. Maintained propagation ability by including cryopreservation in the breeding programme will provide a very useful link between breeding and mass propagation. The results are encouraging, but further improvement of the standard protocol is necessary.
Soil carbon dioxide fluxes and profile concentrations in two boreal forests
Authors: Billings S A , Richter D D , Yarie J
Published: April 2011

Because a large fraction of the world's carbon exists in the soil of boreal forests, understanding how soil temperature and moisture affect soil respiration is vital for predicting soil response to climate change. We measured soil respiration and CO2 concentrations within soils of floodplain and upland forests in interior Alaska from 1996 to 1997. At each site, a 0.10-ha-area shelter was constructed that prevents summer precipitation from infiltrating into the soil. Measurements of soil profile CO2, soil respiration, soil temperature, and soil moisture were made inside (treatment) and outside (control) the sheltered areas through two growing seasons and the winter of 1996-1997. Sheltered soils had decreased profile concentrations and surface flux of CO2. At the upland control site, individual flux rates ranged from 0.10 to 0.95 g·m-2·h-1 in the summer and at sites under the shelter from 0.10 to 0.53 g·m-2·h-1. Rates at the floodplain control site ranged from 0.11 to 1.45 g·m-2·h-1 and under the shelter from 0.11 to 0.55 g·m-2·h-1. Fick's Law could predict surface CO2 flux when the CO2 concentration gradient within the profile accurately represented the soil surface gradient and biological sources and sinks of the gas did not overwhelm flux calculations.
Effect of acorn size on development of northern red oak 1-0 seedlings
Authors: Kormanik P P , Sung S S , Kormanik T L , Schlarbaum S E , Zarnoch S J
Published: April 2011

The effect of acorn size on seedling development was determined for 20 northern red oak (Quercus rubra L.) mother tree selections from the USDA Forest Service's Eastern Tennessee Watauga seed orchard. Acorns from each mother tree were visually separated into three size groups, weighed, and sown separately in forest nurseries located in Georgia, North Carolina, and Tennessee. Seedling height, root collar diameter, and survival within sibling seedlots were significantly related to acorn mass. The three sizes of acorns showed the same trends in seedling development among the four nurseries. Heritability (h2) estimates for the variables were uniformly high among all acorn sizes. A wide range in sibling seedling quality occurred within each acorn size class regardless of nursery location. This suggests that while sizing of acorns into several categories may result in more uniform germination within a seedbed, it will not result in uniform seedling development even when using sibling seedlots and acorns of uniform size.
A transition from gap to tree-island regeneration patterns in the subalpine forest of south-coastal British Columbia
Authors: Brett Robert B , Klinka Karel
Published: April 2011

We examined regeneration patterns and their relationships to snow and microsite factors in subalpine old-growth stands in the Coast Mountains near Vancouver, B.C. Regeneration patterns resembled those in tree islands of the subalpine parkland more than those in gap-driven stands at lower elevations. Regeneration was overrepresented on mounds and close to a canopy tree where snow melted earliest. In contrast to lower elevation stands, canopy cover was mostly unrelated to regeneration patterns, a result that we attribute to relatively homogeneous light levels in the understory and to the confounding influence of late-melting snow, especially in canopy gaps. The absence of colonization in some gaps and very slow colonization in others further demonstrated that gap creation is not required for canopy turnover. Tree-island regeneration patterns were more clearly expressed by Alaska yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach), a species near the upper limit of its elevational range, than by mountain hemlock (Tsuga mertensiana (Bong.) Carr.), a species in the middle of its range. We conclude that cutting is inappropriate in stands where tree-island regeneration patterns predominate because of the uncertainty of regeneration success.
Nutrient stores and dynamics of woody detritus in a boreal forest: modeling potential implications at the stand level
Authors: Krankina Olga N , Harmon Mark E , Griazkin Anatolii V
Published: April 2011

Concentrations of 14 chemical elements (Al, B, C, Ca, Cu, Fe, K, N, Mg, Mn, Na, P, S, Zn) were measured in wood and bark of 126 sample trees representing different stages of decomposition in three major tree species of northwestern Russia: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.), and birch (Betula pendula Roth.). Changes in nutrient stores in decay classes were calculated with adjustments for the loss of density and volume by dead trees. Although the concentration of many nutrients increased relative to the estimated initial level, the total amount of most nutrients contained in dead trees declined with decay. For example, nitrogen stores declined from decay class 1 to 4 by 45% for birch, 39% for spruce, and by 60% for pine. The rate and pattern of these losses varied by nutrient and by species and were primarily related to the patterns of bark loss. Pine lost bark early in the process of decomposition and released many essential nutrients (i.e., N, P, Ca) at the early stages, while birch retained most of its bark throughout the decomposition process and lost nutrients more gradually. The temporal dynamics of N, Ca, and K loss in pine were examined using a chronosequence approach, and the results were used in stand-level modeling. The analysis of modeling results suggests that, in northwestern Russia, post-disturbance release of nutrients from woody detritus can potentially supply a large proportion of the net N, Ca, and K accumulation in live forest biomass.
Effect of coppicing on root system morphology and its significance for subsequent shoot regeneration of birches
Authors: Paukkonen Katri , Kauppi Anneli
Published: April 2011

The growth of the root system after stem cutting and the effects of the root system and its size on the regeneration of stem are poorly known. These aspects were here investigated in 8-year-old silver birch (Betula pendula Roth.) and common white birch (B. pubescens Ehrh.) growing in the field. One eighth of the root systems of birches of both sprout and seed origins were excavated for morphometric analysis. Seven years after the first cutting, fresh mass, length, and diameter of the roots of sprout-origin B. pendula were smaller than those of seed-origin ones. After the cutting of the experimental season, the root system did not develop new structural root tips. When both root pruning and stem cutting were performed, stumps sprouted well by July, but the number of sprouts decreased clearly by August. The positive effect of stem cutting on sprouting disappears in a few years in these species. As the size of the root system does not clearly influence the growth of sprouts, the competition of root systems of adjacent trees does not restrict the shoot growth of birch plants at least in planted birches up to about 10 years of age.
The response of Härtel's turbidity test is controlled by the acidity of the conifer needle extracts rather than by the availability of Ca2+ ions
Authors: Pfeifhofer Hartwig W
Published: April 2011

Härtel's turbidity test (Trübungstest) has been one widely used diagnostic test for air pollution injury for decades. This test is based on the extraction of lipophilic substances into an aqueous suspension, whose light absorption is used as an indication of exposure to pollution. Little is known about the underlying principles controlling the response of the test. In this study, the influence of the cations Li+, Na+, K+, and Ca2+ and that of the anions Cl-, Br-, I-, and SO42- on the response of Härtel's test was reinvestigated. In contrast to an earlier study, both the extracts' absorbance and acidity were monitored. Additionally, the effects of the Ca-chelating agents ethylenediaminetetraacetate (EDTA) and oxalic acid were compared with that of deionized water and different buffers. All effects of ions including that of Ca2+ on the response of the test were accompanied by shifts of the extracts' acidity. Even small changes in the pH caused significant variations in the test's response. On the other hand, addition of the Ca chelating agents EDTA and oxalic acid to the solvent did not affect the response of the test when the pH was equal to solvents without Ca chelating compounds. Therefore, the previously published assumption that the availability of Ca2+ could be the main principle of the test's reaction mechanism was not confirmed.
Genetic variation in cold hardiness of Douglas-fir in relation to parent tree environment
Authors: Balduman L M , Aitken S N , Harmon M , Adams W T
Published: April 2011

The extent to which parent trees within breeding zones of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) are locally adapted to their native environments was evaluated. Forty families from each of one Coastal and one Cascade breeding population in Oregon were assessed for cold hardiness and growth phenology, and family means for traits were summarized using principal components analysis (PCA). Composition of the first two principal components (PCs) was consistent between breeding zones, years, and test sites. PC-1, describing 39-46% of trait variation, represents a suite of traits related to spring phenology and spring cold hardiness. PC-2, describing 20-22% of trait variation, consists of cold-hardiness traits not associated with phenology. The first two PCs from each population, as well as univariate traits, were regressed on parent tree location variables and modeled climatic indices separately. In the Coastal zone, PC-1 was weakly but significantly related to temperature and moisture regimes (0.176 [Formula: see text] r2 [Formula: see text] 0.235), varying with elevation and distance from the ocean. PC-2 was related to temperature and moisture regimes in both populations (0.087 [Formula: see text] r2 [Formula: see text] 0.249). These relatively weak geographic patterns for adaptive traits within breeding zones suggest that current zone size is not excessive and could likely be increased north or south.
Fire-scar formation and compartmentalization in oak
Authors: Smith Kevin T , Sutherland Elaine Kennedy
Published: April 2011

Fire scars result from the death of the vascular cambium resulting from excessive heating, which exposes sapwood to infection and initiates the wood decay process. In southeastern Ohio, prescribed fires in April 1995 and 1997 scarred Quercus prinus L. and Q. velutina Lam. Low-intensity fires scorched bark and produced scars, primarily on the downslope side of the stem. Eighteen scorched trees (4-23 cm at DBH) were dissected in November 1997, 14 of which had fire scars. The vascular cambium beneath natural bark fissures was most vulnerable to injury. No charred or scorched wood was associated with scars of trees exposed to single fires; wood exposed by scars from the 1995 fire was charred by the 1997 fire. Consistent with the compartmentalization process, discoloration and whiterot occurred within compartment boundaries of wood present at the time of wounding. Scars from the prescribed fires were consistent in size and shape with scars in nearby oak trees previously hypothesized to have been burned prior to 1950.