bluuebunny/crossref_metadata_2025 huggingface dataset:
Genomics and quantitative genetics
Authors: van Buijtenen J P
Published: April 2011

The interaction between genomics and quantitative genetics has been a two-way street. Genomics contributed genetic markers and genetic maps making it possible to study quantitative trait loci (QTLs), and quantitative genetics contributed new theories and computational techniques to deal with the data generated by QTL studies. QTL studies in forest trees have led to the discovery of a few major genes masquerading as quantitative genes, such as genes for rust resistance in several pine species. QTLs for many traits including height growth, leaf traits, wood specific gravity, flowering, frost resistance, disease resistance, and ease of vegetative propagation were found in one or more species. Spring cold hardiness in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) holds the record for number of QTLs with 14. Generally the number is under seven. The effects are often large, but this may often be due to small population sizes. At this time the impact on forest tree breeding is small, although the potential is certainly there. An interesting marker aided back-crossing program is underway in American chestnut (Castanea dentata (Marsh.) Borkh.).
Conservation and management of genetic diversity: a domestic animal perspective
Authors: Barker J SF
Published: April 2011

In the context of domestic animal diversity, the term "breed" is conventionally used for all recognized populations. There are in total about 5000 breeds, a small proportion of which are in planned programs for genetic improvement, while about 30% are at risk of extinction. The primary focus is on the conservation of breeds, including management for better utilization (breeding programs) and conserving those at risk, with the aim of minimizing the loss of among breed diversity. The majority of the world's breeds are in the developing countries, with production environments that are low to medium input and high stress, and each may be expected to have adapted to its specific environment. Empirical evidence strongly supports the expectation that the genetic basis of population differentiation for fitness traits will be nonadditive, with different adaptive gene complexes evolved in each breed. Genetic improvement programs therefore should start with an adapted population, with selection then for production traits. As not all breeds can be conserved, priorities must be determined. Suggested criteria (breed divergence, risk of breed extinction, breed "merit," and within-breed variation) are presented and evaluated. Similar approaches may be appropriate for the conservation of genetic diversity of forest trees.
Genetic parameters and provenenance variation of Pinus caribaea var. hondurensis in 48 international trials
Authors: Hodge G R , Dvorak W S
Published: April 2011

A total of 23 provenances or sources of Pinus caribaea var. hondurensis (Sénécl) Barr. et Golf. were tested in 48 provenanceprogeny trials in Colombia, Brazil, and Venezuela. In Brazil and Venezuela, 8-year heights were approximately 12 m, while in Colombia, mean 8-year height was less than 8 m. The growth rates of the unimproved material correspond approximately to volumes of 1415 m3·ha1·year1 of wood on sites in Brazil and Venezuela, and 45 m3·ha1·year1 in Colombia. Provenances had similar growth rankings in the different countries, with a type-B provenance correlation of 0.63. The best native provenances were Limón and Guanaja, Honduras. Improved first-generation sources from Queensland, Australia and Zululand, South Africa, were 512% better than the mean of the unimproved provenances, depending on country where planted. Mean single-site heritability for volume growth is approximately 0.18. Potential genetic gain for volume at 8 years from selection within provenance is around 30%. Foxtailing is also under moderate genetic control with heritability around 0.15. Genotype × environment interaction for volume growth is generally higher for tests located in different countries than in the same countries. Selection for age-8 volume using age-5 data would be 93% as effective as selection at age 8.
Recent growth of conifer species of western North America: assessing spatial patterns of radial growth trends
Authors: McKenzie Donald , Hessl Amy E , Peterson David L
Published: April 2011

We explored spatial patterns of low-frequency variability in radial tree growth among western North American conifer species and identified predictors of the variability in these patterns. Using 185 sites from the International Tree-Ring Data Bank, each of which contained 1060 raw ring-width series, we rebuilt two chronologies for each site, using two conservative methods designed to retain any low-frequency variability associated with recent environmental change. We used factor analysis to identify regional low-frequency patterns in site chronologies and estimated the slope of the growth trend since 1850 at each site from a combination of linear regression and time-series techniques. This slope was the response variable in a regression-tree model to predict the effects of environmental gradients and species-level differences on growth trends. Growth patterns at 27 sites from the American Southwest were consistent with quasi-periodic patterns of drought. Either 12 or 32 of the 185 sites demonstrated patterns of increasing growth between 1850 and 1980 A.D., depending on the standardization technique used. Pronounced growth increases were associated with high-elevation sites (above 3000 m) and high-latitude sites in maritime climates. Future research focused on these high-elevation and high-latitude sites should address the precise mechanisms responsible for increased 20th century growth.
Accuracy and efficiency of area classifications based on tree tally
Authors: Williams Michael S , Schreuder Hans T , Czaplewski Raymond L
Published: April 2011

Inventory data are often used to estimate the area of the land base that is classified as a specific condition class. Examples include areas classified as old-growth forest, private ownership, or suitable habitat for a given species. Many inventory programs rely on classification algorithms of varying complexity to determine condition class. These algorithms can be simple decision trees applied in the field or computer calculations applied on a field data recorder or after the data are collected. The advantages to using these algorithms are consistent classification of the condition class, reduced crew training, and the ability to define new condition classes after the data are collected, which will be referred to as postclassification. We discuss three types of the errors that can occur when these types of algorithms are employed and quantify the potential for error with examples. The examples are substantial oversimplifications of the true problem, but they show how difficult it is to determine anything but the most general condition classes using plot data alone. A discussion of how condition class is scale dependent and some general guidelines and recommendations are given.
Vegetation management and site preparation effects on 13C isotopic composition in planted white spruce
Authors: Staples Thomas E , Van Rees Ken CJ , Knight J Diane , Kessel C van
Published: April 2011

Moisture availability is the factor that most commonly influences the discrimination against 13C fixation (Δ) by C3 plants. Therefore, by changing the availability of moisture by way of controlling competing vegetation, Δ in white spruce (Picea glauca (Moench) Voss) seedlings should be affected. The objective of this study was to determine the influence of manual brushing on Δ in white spruce seedlings planted in disc-trenched and control (i.e., no site preparation) microsites. The effects of site preparation and vegetation management on soil moisture, photosynthetically active radiation (PAR), and Δ in white spruce seedlings were evaluated over three growing seasons. Vegetation management increased the amount of PAR reaching seedlings in the control and disc-trenched treatments by removing the shading by native vegetation around each seedling. It appears that the increase in PAR reaching seedlings decreased Δ by increasing the photosynthetic consumption of CO2. Differences in soil available moisture (up to 22%) between control and disc-trenched treatments were not reflected in Δ values, contrary to our initial hypothesis. This may indicate that the site was not moisture limiting. Also, these results underline the complexity and difficulty of determining the controlling mechanisms by which Δ is affected.
Balsam fir self-thinning relationship and its constancy among different ecological regions
Authors: Bégin Eric , Bégin Jean , Bélanger Louis , Rivest Louis-Paul , Tremblay Stéphane
Published: April 2011

The constancy of balsam fir (Abies balsamea (L.) Mill.) self-thinning relationship has been investigated among four study areas located in different ecological regions of Quebec's humid boreal forest. These four study areas contained respectively 348, 252, 146, and 55 observations (plots × measures) sampled over a period of up to 40 years. A self-thinning fitting method was developed to position objectively the self-thinning lines but, moreover, to allow comparisons among the different study areas. This method relies on principal component analysis to estimate the self-thinning line parameters and on the "jackknife" procedure to provide a standard error of these estimates. Results demonstrate a concordance for the slope (p = 0.136) and the intercept (p = 0.148) among self-thinning relationships of those study areas. The combination of these four study areas in one large data set, to provide a general estimation of balsam fir self-thinning line, has given a slope of 1.441 with a 4.114 intercept which is in agreement with the 3/2 power law of self-thinning. In this study, this law was able to describe the sizedensity relationship of stands of various ages and growing within different conditions as expressed by the different ecological regions.
Base cation leaching from the canopy of a subtropical rainforest in northeastern Taiwan
Authors: Lin Teng-Chiu , Hamburg Steven P , Hsia Yue-Joe , King Hen-Biau , Wang Lih-Jih , Lin Kuo-Chuan
Published: April 2011

We examined base cation leaching from the canopy of a subtropical rainforest in northeastern Taiwan. The forest is characterized by extremely low levels of base cations in both canopy vegetation and in the soils. The rates of canopy leaching of K+, Ca2+, and Mg2+ were very high, representing up to 30, 35, and 190%, respectively, of the amount stored in leaves. The rate of H+ retention in the canopy was close to the rate of base cation leaching, suggesting that cation leaching is neutralizing acid precipitation. The subtropical forest studied leached cations from the canopy throughout the year, unlike temperate deciduous forests, which are physiologically inert in the winter. The forest canopy of the subtropical forest we studied is impacted by acid deposition and fog throughout the winter because of frequent rainfall and high relative humidity. This continuous exposure to acid precipitation could cause more intense negative effects on the canopy of subtropical forests as compared with temperate forests exposed to similar pollution loads. We suggest that the low base status of subtropical forests growing on low base status soils may make them very vulnerable to the negative effects of air pollution.
Early colonization ofPopuluswood by saproxylic beetles (Coleoptera)
Authors: Hammond H E. James , Langor David W , Spence John R
Published: April 2011

The early colonization of newly created coarse woody material (CWM) by beetles was studied in aspen mixedwood forests at two locations in north-central Alberta. Healthy trembling aspen (Populus tremuloides Michx.) trees, in old (>100 years) and mature (4080 years) stands, were cut to provide three types of CWM: stumps, bolts on the ground (logs), and bolts suspended above the ground to simulate snags. Over 2 years, 1049 Coleoptera, representing 49 taxa, were collected. Faunal structure differed little between the two locations. Species diversity was higher in old than in mature stands, and higher in stumps and logs than in suspended bolts; however, these "snags" tended to have higher abundance when compared with stumps and logs. Overall beetle abundance and the catch of wood-boring beetles was significantly higher in the first year post-treatment, mainly because of the ambrosia beetle (Trypodendron retusum (LeConte)) and one of its predators, Rhizophagus remotus LeConte; however, beetle diversity was higher in the second year, suggesting that early wood-boring species may "precondition" the wood for a number of succeeding species. The high turnover rate of taxa and spatial or temporal variation in faunal structure suggests that effort focused on habitat classification of CWM will facilitate management to conserve saproxylic faunal diversity.
A switching model of bole taper
Authors: Valentine H T , Gregoire T G
Published: April 2011

Numerical switches are employed to change the values of two exponents in a variable-form model of bole taper. The taper of a bole is modeled, with respect to height from the ground, by three connected geometric segments (i.e., a basal, middle, and top segment). The numerical switches provide for either graded or abrupt transition from the basal to the middle segment and from the middle to the top segment. The height of the base of the crown was assumed to be the point of transition between the middle and top segments. Crown height can be either measured or estimated with a simple submodel that emerged from the taper model. Compared with estimated crown height, the use of measured crown height improved the precision of the taper model when fitted for Liquidambar styraciflua L., but not Pinus elliottii Engelm., or Pinus ponderosa Dougl. ex P. and C. Laws. The taper model also was fitted for Liriodendron tulipifera L., but crown height was not available. Correlation among residuals within individual boles was accounted for in the fitting procedure. The taper model proved to be reasonably precise for all four species, and the parameters are easy to interpret.
Responses to canopy openings in architectural development of saplings in eight deciduous broad-leaved tree species
Authors: Takahashi Koichi , Seino Tatsuyuki , Kohyama Takashi
Published: April 2011

Crown-architectural responses to small canopy openings, in relation to relative height growth rate (RHGR), were examined in saplings (0.52.3 m tall) of eight deciduous broad-leaved tree species in northern Japan. Five species were lateral-growth type with high leaf-support cost (branch mass per leaf area) to display many small leaves over a wide area, while three species were vertical-growth type with low leaf-support cost due to a small number of large leaves along a main trunk. In closed-canopy conditions, the lateral-growth species showed a greater increase in leaf area with increasing sapling size than the vertical-growth species. Net production rate (NP) per leaf area was not clearly different between the two groups. As a result, NP per sapling also increased to a greater extent with increasing sapling size for the lateral-growth species. The NP per leaf area was increased in canopy openings for the two groups, but this increase was not clearly distinguished between the two groups. The vertical-growth species supported greater leaf area per sapling in canopy openings because of the low cost of leaf support, which resulted in a greater increase in NP per sapling compared with the lateral-growth species. The lateral-growth species allocated more to trunk in canopy openings, keeping leaf area constant and decreasing the cost of leaf support. The RHGR of the vertical-growth species tended to be greater than that of the lateral-growth species in closed-canopy conditions. RHGR of all species was increased in canopy openings to a similar degree in both groups. Multiple regression analysis showed that RHGR of the lateral-growth species depended on both NP per sapling and allocation to trunk, while that of the vertical-growth species depended strongly on NP per sapling alone. Thus, saplings of each group responded to canopy openings in contrasting ways to increase RHGR.
ReplyA re-examination of the effects of fire suppression in the boreal forest
Authors: Ward P C , Tithecott A G , Wotton B M
Published: April 2011

Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305) presented data that indicated fire suppression activities in Ontario led to reductions in average annual area burned and greater numbers of small fires, compared with what would have been observed in the absence of suppression. Miyanishi and Johnson (K. Miyanishi and E.A. Johnson. 2001. Can. J. For. Res. 31: 14621466) have questioned aspects of that report, suggesting that the evidence does not demonstrate that suppression influences fire size or frequency. Fire-history studies in Ontario's forests and recent fire disturbance records do show that the fire-return interval has lengthened considerably in Ontario's protected forest since pre-suppression times. Analysis of forest inventory age-class distributions also reflect a reduction in overall forest disturbance rates in the past 40 years. Average annual burn fractions (ABF) calculated for protected and unprotected forests in northwestern Ontario for the period 1976-2000 show an ABF of 1.11% in the unprotected forest and only 0.34% in the protected forest. There is clear evidence that fire suppression in Ontario contains many fires at small sizes that would have otherwise grown to larger sizes, and reduces the overall average annual area burned in the protected forest.
Monte Carlo approaches to sampling forested tracts with lines or points
Authors: Valentine H T , Gove J H , Gregoire T G
Published: April 2011

Several line- and point-based sampling methods can be employed to estimate the aggregate dimensions of trees standing on a forested tract or pieces of coarse woody debris lying on the forest floor. Line methods include line intersect sampling, horizontal line sampling, and transect relascope sampling; point methods include variable- and fixed-radius plot sampling, and point relascope sampling. We demonstrate that the line methods can be interpreted as applications of importance sampling and that point methods can be interpreted as two-stage applications of importance sampling and crude Monte Carlo. Interestingly, each of the line methods also can be implemented as a point method. Operationally, the two stages of a point method effectively reduce to a single stage. Estimators of target parameters are derived from the Monte Carlo approach for all six methods. Two new methods of estimating cross-sectional areas of slanted or tilted log-shaped objects are suggested for use in line intersect sampling. Boundary problems also are discussed.
Climatic and human influences on fire history in Pike National Forest, central Colorado
Authors: Donnegan Joseph A , Veblen Thomas T , Sibold Jason S
Published: April 2011

We investigated interannual and multidecadal variability in fire regimes, as related to climate and human land-use in Pike National Forest, central Colorado. Short and long-term trends in fire-scar records were related to tree-ring proxy records of moisture availability and to variability in El Niño  Southern Oscillation (ENSO). Fire occurrence is strongly tied to interannual drought conditions and is associated with cycles of ENSO. Fire events tend to occur in years of reduced moisture availability (La Niña years) and are often preceded by 24 years of increased moisture availability (El Niño years). A period of reduced variability in the tree-ring record from 1760 to 1820 AD, roughly corresponds to a period of reduced fire occurrence from approximately 1792 to 1842. Coincident with increased fire occurrence, variability in the climate proxies was high in the middle to late 1800s until the early 1900s. Multidecadal impacts through land use are also evident in the fire record with sharp increases during Euro-American settlement in ca. 1850 and abrupt declines with the start of active fire suppression after ca. 1920. Both humans and climatic variation appear to have interacted synergistically to create long-term trends in fire occurrence over the past two centuries.
The pollination mechanism of western white pine
Authors: Owens John N , Catalano Glenda , Bennett Jordan S
Published: April 2011

The phenology of post-dormancy pollen cone, pollen, seed cone, and ovule development was determined for western white pine (Pinus monticola Dougl. ex D. Don) growing at a coastal and an interior seed orchard in British Columbia. Pollen cones were preformed and overwintered at the sporogenous cell stage before resuming development in early April. Meiosis occurred in May, and pollen was mature by late May or early June. Potential seed-cone buds resumed development in mid-April, and all bracts and ovuliferous scales were initiated before seed-cone buds burst. Comparable stages of development occurred about 2 weeks earlier at the coastal orchard. Numerical phenological stages were assigned to both pollen-cone and seed-cone development. Pollen-cone and seed-cone phenology were very dependent on temperature, whereas pollen release was dependent on both temperature and drying. Degree-days are a useful way to predict seed cone receptivity and to a lesser extent pollen shed at one site in successive years but not between sites. Receptivity and pollen release were fairly synchronized at both sites in both years of the study. The pollination mechanism is described and was similar to other pines studied in a similar manner. Seed cones were erect at receptivity and ovules inverted. Lipid microdrops were secreted on the micropylar arms to which the saccate pollen adhere. After several days of pollen collection on the arms and other cone surfaces, a pollination drop was secreted from the ovule, and if it was large it filled the space between the micropylar arms. Many large pollination drops were observed in cones at the coastal orchard, and the drops scavenged pollen from the arms and nearby cone surfaces. Few and small pollination drops were observed in cones at the interior orchard where low humidity may cause rapid evaporation of the drop. Water applied as a spray at the interior site increased the size of pollination drops or created artificial drops between the arms. At both sites water applied as a fine spray after pollen shed carried pollen from the hairs on the margins of the bracts and scales into the cone and to the ovules. The pollination mechanism in western white pine is well adapted to the wet humid coastal environment but not as well adapted to the dry interior.
Comparison of basic density and longitudinal shrinkage in tension wood and opposite wood in young stems of Populus euramericana cv. Ghoy when subjected to a gravitational stimulus
Authors: Jourez B , Riboux A , Leclercq A
Published: April 2011

In a greenhouse, under controlled conditions, young shoots, taken from poplar cuttings (Populus euramericana (Dole) Guinier cv. Ghoy), were artificially bent to quantify the modifications of physical properties induced by a gravitational stimulus. At the end of the growing season, basic density and longitudinal shrinkage were measured on very small samples taken from pure tension wood tissue observed on the upper face of the inclined axis and compared with opposite wood tissue, free of gelatinous fibers, developed on the opposite lower face. In a second step, shoots bent at two different lean intensities were analyzed. In young poplar wood, gravitational stimulus was found to have a significant effect on physical properties. Relations between basic density and longitudinal shrinkage are different depending on the types of wood considered. Shrinkage appears more sensitive to lean intensity in the range considered here.
Aspect-dependent high-irradiance damage in two transplanted foliose forest lichens,Lobaria pulmonariaandParmelia sulcata
Authors: Gauslaa Yngvar , Ohlson Mikael , Solhaug Knut Asbjørn , Bilger Wolfgang , Nybakken Line
Published: April 2011

High-irradiance damage in two epiphytic lichens was recorded as reduction in predawn photosystem II quantum yield (Fv/Fm) measured at the end of a night with full hydration. Measurements were repeated during a 29-day transplantation in early summer at defined aspects (north, east, south, west, perpendicular to the sun at noon, and shade) in an open site at 60°N. These treatments included the contrasts that remaining lichens adjacent to clear-cut areas could experience subsequent to logging. The Fv/Fmvalues declined linearly with the mean irradiance during the previous day, with the old-forest epiphyte Lobaria pulmonaria (L.) Hoffm. being consistently more severely photoinhibited than the ubiquitous Parmelia sulcata Taylor. Both irradiance levels and predawn Fv/Fmvalues decreased in the following direction: shaded controls > transplants facing north > south, east, west > transplants perpendicular to the sun. Since the transplantation period happened to be very rainy with favorable conditions for recovery, all transplants survived. Nevertheless, photoinhibition was sustained from one day to the other, especially in the old-forest species L. pulmonaria, implying a long-lasting strain, which could affect long-term performance and survival of thalli. The results are discussed in a wider context including confounding effects of irradiance in forests, with implications to facilitate lichen conservation in managed forests.
Genotype × trial interaction and stability across sites in 11 combined provenance and clone experiments withPicea abiesin Denmark and Sweden
Authors: Karlsson Bo , Wellendorf Hubert , Roulund Hans , Werner Martin
Published: April 2011

In 1997, eleven combined Picea abies (L.) Karst. provenance and clone trials were assessed in two series, with identical genetic constitution and design, in locations ranging from western Denmark to central Sweden, after 14 and 11 years, respectively. The phenotypic variation was larger for mixtures of 24 clones than for seedlings in one series, although 10 times more genotypes were represented amongst the seedlings. This was explained by random C-effects due to propagation. Provenances of seedlings and clone mixtures were fairly stable across sites. Statistically significant clone × trial interaction of growth traits were of the same magnitude as the clonal effects. The median genotypic correlation across sites for total height growth was 0.54. Ecovalence values for growth indicated that most clones contributed about equally to the interaction, with a tendency for clones with early bud break to give a larger contribution. Damage caused by late spring frost was assumed to be a main cause of genotype × environment interaction. Since interactions relatively were more pronounced for growth increment than for the latest height, the interaction seems to increase with age. Cluster analysis based on genotypic correlations between pairs of trials gave a very scattered geographic pattern of the test sites. The results did not justify any suggestions for changes in the P. abies breeding strategy.
A comparison of growth and physiology in Picea glauca and Populus tremuloides at different soil temperatures
Authors: Landhäusser Simon M , DesRochers Annie , Lieffers Victor J
Published: April 2011

Trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) seedlings were grown at uniform air temperatures but different soil temperatures (5, 15, and 25°C), and gas-exchange and growth characteristics were examined during active growth and early dormancy. At 5°C, Populus tremuloides had no root growth and limited growth in leaf area and shoot mass compared with the large increases in leaf and shoot mass at 25°C. In contrast, Picea glauca had some root growth at 5°C and moderate growth of roots at 15 and 25°C; however, there were no differences in aboveground mass at the different soil temperatures. Net assimilation and stomatal conductance in Populus tremuloides were reduced with decreasing soil temperatures, while in Picea glauca soil temperatures did not affect these gas-exchange variables. In both species, root mass was higher in the dormant period than during the growing period, while root volume remained constant. Generally, the growth variables of Populus tremuloides were more suppressed by cold soils than in Picea glauca. Root total nonstructural carbohydrates (TNC) decreased between the active growth and dormancy period by nearly 50% in Populus tremuloides, while there was no change in TNC in Picea glauca. Results suggest a more conservative use of TNC reserves in Picea glauca combined with a tolerance to cold soil temperatures compared with Populus tremuloides.
Growth, physiology, and leachate losses inPicea glaucaseedlings (1+0) grown in air-slit containers under different irrigation regimes
Authors: Lamhamedi Mohammed , Lambany Gil , Margolis Hank , Renaud Mario , Veilleux Linda , Bernier Pierre Y
Published: April 2011

In production tunnels, time domain reflectometry (TDR) was used to manage irrigation and leaching by controlling water content in the rhizosphere of air-slit containerized white spruce (Picea glauca (Moench) Voss) seedlings (1+0). Seedlings were exposed to four irrigation regimes (v/v: IR-60%, IR-45%, IR-30%, and IR-15%) during the first growing season to assess IR effects on growth, gas exchange, nutrient uptake, carbohydrates, root architecture, and leaching. In the province of Quebec, seedling producers generally maintain a high substrate water content (>50%, v/v) during all growth phases. The accuracy and feasibility of using TDR to decrease irrigation without affecting the material attributes of the seedlings at the end of the first growing season was confirmed. However, seedlings grown under IR-15% had significantly lower height, root collar diameter, shoot and root dry masses, root surface, root length, net photosynthesis, and nutrient contents than seedlings grown under IR-30%, IR-45%, and IR-60%. In comparison with IR-30% and IR-45%, the application of IR-60% produced no increase in shoot or root growth, mineral nutrition, and carbohydrates. Seedlings grown under IR-15%, IR-30%, and IR-45% used approximately 28, 37, and 46%, respectively, of the amount of water applied under IR-60%. Nutrient losses including anions and cations under IR-60% were higher in comparison with the other IRs. Maintaining a water content in the rhizosphere that changes with the stage of seedling development is suggested to optimize growth and to avoid excess irrigation and leaching.
Biological performance of the white pine weevil in different host species and in two ecological regions of southern Quebec
Authors: Boucher Dominique , Mauffette Yves , Lavallée Robert
Published: April 2011

The performance of the white pine weevil (Pissodes strobi Peck) was studied on five different host species: Norway spruce (Picea abies (L.) Karst.), white spruce (Picea glauca (Moench) Voss), red spruce (Picea rubens Sarg.), jack pine (Pinus banksiana Lamb.), and eastern white pine (Pinus strobus L.). Attacked terminal leaders were collected prior to adult emergence, within two different ecological regions of Quebec, the Outaouais and Appalaches regions. According to their natural range, jack pine was studied only in the Outaouais region and red spruce only in the Appalaches one. Weevil performance did not differ between regions but differed among host species. The number of eggs laid per leader was greatest on jack pine, white pine, and Norway spruce (279, 219, and 218 eggs per leader, respectively). Adults emerging from white pine were the heaviest (0.0104 g). The number of adults per leader was greater on Norway spruce and white pine (34 and 23 adults, respectively), and survival tended to be greater on Norway spruce and white spruce leaders (18 and 15%, respectively). Norway spruce had the longest leaders, and jack pine had the thickest ones. Leader dimensions were correlated with all variables of weevil performance, except insect survival, but these characteristics explain only a small part of the variation in weevil performance. Norway spruce and white pine can be considered favourable hosts for rapid population buildup according to the high number of emerging adults per attacked leader.
Variation in xylem anatomy of selected populations of lodgepole pine
Authors: Wang Tongli , Aitken Sally N
Published: April 2011

Variation in xylem anatomy among selected populations of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) was examined using digital image analysis based on an annual growth ring (age 10) per tree. Four subpopulations were selected using the following criteria for height growth and wood density: (i) fast growth and high density; (ii) slow growth and high density; (iii) fast growth and low density; and (iv) slow growth and low density. Significant differences were found among subpopulations for several anatomical parameters including tracheid density, lumen size, and cell wall thickness that may affect the economic value and utilization of wood. Principal component analysis indicate that the first four principal components (PCs) were associated with (i) ring area (PC1), (ii) earlywood density (PC2), (iii) latewood density (PC3), and (iv) lumen shape in earlywood (PC4), suggesting that these aspects of wood properties and growth are controlled by different sets of genes. Relative contributions of total number of tracheids, tracheid lumen size, and cell wall thickness to ring area and correlations between cell wall area proportion and X-ray density are discussed.
The effects of partial cutting on forest plant communities of western hemlock  Sitka spruce stands in southeast Alaska
Authors: Deal Robert L
Published: April 2011

The effects of partial cutting on plant species richness, community structure, and several understory species that are important for deer forage were evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 1296 years ago when 1696% of the former stand basal area was removed. The species richness and community structure of understory plants were similar in uncut and partially cut plots. However, plots where more than 50% of the basal area was cut had a significantly different plant community structure. Species composition and abundance also appeared to be distinctly different between hemlock-dominated and spruce-dominated stands. Partial cutting did not significantly change abundance for most of the important forage species for deer. The similarity in plant community structure between partially cut and uncut old-growth stands may be related to forest stand structures. The heterogeneous stand structures that develop after partial cutting are more similar to old-growth stands than to the uniform young-growth stands that develop after stand replacing disturbances such as clear-cutting.
Fine sediment deposition in streams after selective forest harvesting without riparian buffers
Authors: Kreutzweiser David P , Capell Scott S
Published: April 2011

Fine sediment accumulation was measured in streams in low-order forest watersheds across a gradient of selective harvesting with no protective riparian buffers. Comparisons were made among sites in selection-cut (40% canopy removal), shelterwood-cut (50% canopy removal), diameter limit cut (about 85% canopy removal), and undisturbed tolerant hardwood catchments. These were further compared with a headwater stream catchment not harvested but affected by logging road activities. The greatest increases in fine inorganic sediment occurred at the road-improvement site with mean bedload estimates more than 4000 times higher than pre-manipulation values. Sediment bedload was still significantly elevated 2 years after the road-improvement activities. Significant increases (up to 1900 times the pre-harvest average) in inorganic sediment also occurred at the highly disturbed diameter-limit site as a result of heavy ground disturbance and channeled flowpaths from skidder activity in riparian areas. Similar increases were detected at the selection-cut site but were attributable to secondary road construction in the runoff area. In the shelterwood harvest area, where logging roads were not a factor, no measurable increases in sediment deposition were detected. There was little indication that harvesting activities at any site affected the organic fraction or the particle size distribution of fine sediments. The results of this study suggest that riparian buffer zones may not be necessary for selective harvesting in hardwood forests at up to 50% removal, at least in terms of reducing sediment inputs.
RAPD markers in parentage confirmation of a valuable breeding progeny of European white birch
Authors: Åkerman S. , Tammisola J. , Lapinjoki S.P. , Söderlund H. , Kauppinen V. , Viherä-Aarnio A. , Regina M. , Hagqvist R.
Published: April 2011

The general applicability of RAPDs (random amplified polymorphic DNAs) as genetic molecular markers for Betulapendula Roth was evaluated. On average 2.5 clear, potentially useful marker bands were generated per primer from the DNA of a randomly selected birch tree using a set of 60 commercial 10-mer primers. The resulting fragments were typically between 200 and 700 base pairs in length. A novel pooled-progeny analysis of parentage was applied for a posteriori confirmation of parents of an old breeding experiment. The method that saves labour in several laboratory steps is regarded as useful for screening possible errors in breeding. The present work dealt with a case in which one parent was known and there were two candidates for the other. The correct parent was independently confirmed using nine different RAPD loci. The validity of the pooled-progeny application was confirmed by conventional segregation analysis. In this connection, segregation of RAPD alleles at additional loci in the B. pendula cross was also studied.
Development of an improved model estimating the nutrient content of the bole for four boreal tree species
Authors: Rochon P , Paré D , Messier C
Published: April 2011

An improved model for estimating nutrient contents of the commercial portion of tree boles was developed for four boreal tree species (Populus tremuloides Michx., Betula papyrifera Marsh., Picea glauca (Moench) Voss, and Abies balsamea (L.) Mill.). This model considers the spatial pattern of variation of nutrient concentrations inside the bole and its relationships with tree size. For all species-nutrient combinations, no significant pattern was found for vertical variations in nutrient concentrations, while two types of nonlinear models, using distance from the tree periphery as the independent variable, fit the pattern of horizontal (or radial) variations. These patterns of variability were used to estimate the global nutrient concentration of the bole by using mathematical integration. The values obtained with this method were generally lower, especially for large stems, than values obtained with traditional methods that do not consider the variability of nutrient concentrations inside the bole. This improved model would permit better estimates of the amounts of nutrients lost in biomass upon forest harvesting, as well as internal cycling of nutrients within the bole.
Planting density and tree-size relations in coast Douglas-fir
Authors: Scott William , Meade Rodney , Leon Richard , Hyink David , Miller Richard
Published: April 2011

Test plantations were established in western Washington and Oregon to compare tree growth at six initial planting densities ranging from 300 to 2960 trees/ha (120 to 1200/acre). A size-density relation was visually apparent 3 to 4 years after planting. Inventory data from the oldest 11 trials (5 or 6 years after planting) showed that initial spacing strongly influenced early growth of coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii). Average height and diameter at breast height were progressively larger as planting density increased; at the widest spacing (lowest stand density), average height was 75% and average diameter at breast height was 67% of that at the closest spacing. We have no firm explanation for the early faster tree growth at close spacings. Trees planted at 2960 trees/ha (1200 trees/acre) attained breast height (1.3 m) 2 years earlier than trees planted at a density of 300/ha (120/acre). This finding has practical significance to current efforts to achieve early establishment of plantations.
Assessing processes of intraspecific competition within spatially heterogeneous black spruce stands
Authors: Newton P F , Jolliffe P A
Published: April 2011

The objective of this study was to develop and subsequently apply an individual-tree analytical approach for assessing resource competition processes within monospecific, even-aged, and spatially heterogeneous black spruce (Picea mariana (Mill.) BSP) stands. The approach consisted of five basic steps: (1) ranking competitors with respect to subject tree size using a relative scale, (2) stratifying competitors into competition strata based on their relative size differential with respect to a subject tree, (3) quantifying the intensity of competition within each stratum using spatially explicit local competition indices and subsequently formulating directional-specific cumulative indices, (4) regressing relative measures of stem growth against each directional-specific index, and (5) graphically and statistically assessing differences in resultant standardized regression coefficients as competition accumulated upward from below and downward from above. This analytical framework was used with stem growth data derived from 401 subject trees situated within 18 monospecific, even-aged, density-stressed, and spatially heterogeneous black spruce stands. The results indicated directional-specific asymmetrical relationships between subject trees and their neighbours in which increasing competition from above resulted in declines in stem production. Consequently, these results were in accord with those expected when competition is dominated by a resource preemption process.
Compatibility of different pollination techniques with microprojectile bombardment of Norway spruce and Scots pine pollen
Authors: Aronen Tuija S , Nikkanen Teijo O , Häggman Hely M
Published: April 2011

Transformed pollen could be used in crossings to provide a new approach for producing transgenic seedlings of gymnosperms recalcitrant to tissue culture. The aim of this study was to investigate different pollination techniques in Norway spruce (Picea abies (L.) Karst.) and in Scots pine (Pinus sylvestris L.) using both natural pollen and pollen bombarded with DNA-coated microprojectiles. Cone and seed set after liquid pollinations with natural and bombarded pollen was compared with conventional crossings in which dried natural pollen was used. Liquid pollination proved inferior to conventional crossings. In Norway spruce, the percentages of mature cones and full seeds were lower with liquid pollination than with the conventional method; and in Scots pine, the number of conelets was lower than in pollinations in which dried pollen was used. With bombarded pollen, the results were even lower. To improve possibilities to obtain transgenic progenies, a method was developed that allows the use of bombarded pollen in conventional crossings. This technique is based on dehydration of pollen suspensions and storage at -20°C, which results in a slight decrease in the germination ability of pollen but leads to a high level of the beta -glucuronidase reporter gene expression. This is the first report on transient foreign gene expression in plant material stored in a metabolically inactive form for 1 month before gene expression was assayed.
Mycorrhization, physiognomy, and first-year survivability of conifer seedlings following natural fire in Grand Teton National Park
Authors: Miller Steven L , McClean Therese M , Stanton Nancy L , Williams Stephen E
Published: April 2011

Ectomycorrhiza formation, survivability, and physiognomic characteristics were assessed for conifer seedlings encountered 1 and 2 years postfire in the Huck burn site near Grand Teton National Park. Pinus contorta Dougl. ex Loud. germinated and was abundant throughout the first growing season. Abies lasiocarpa (Hook.) Nutt. germinated during May and June but was rarely encountered by September. First-year survivorship of P. contorta seedlings was about 50% for east-facing burn and edge and west-facing burn treatments. Mortality was higher in the west-facing edge treatment at about 64%. Pinus contorta seedlings collected in July and August had allocated approximately 75% more biomass to epicotyl production than to hypocotyl production, whereas by September seedlings had allocated 30-50% of their biomass to hypocotyls, regardless of site or treatment. Few or no ectomycorrhizae were formed until September. By September 100% of surviving seedlings were ectomycorrhizal. The number of ectomycorrhizae was positively correlated with the number of primary needles and the root/shoot ratio. These results highlight the importance of mycorrhizae to conifer seedling survival during the initial growing season and point to alteration of carbon allocation as a primary mechanism affecting seedling survival.
Identification of Armillaria species isolated from bigtooth aspen based on rDNA RFLP analysis
Authors: Frontz T M , Davis D D , Bunyard B A , Royse D J
Published: April 2011

Restriction fragment length polymorphism analysis (RFLP) of the intergenic region (IGR-1) between the 3 ' end of the 26S ribosomal RNA gene and the 5 ' end of the 5S rRNA gene was used to identify 39 isolates of Armillaria species collected from live or recently dead bigtooth aspen (Populus grandidentata Michx.) trees and sucker sprouts in the Tioga State Forest, Pennsylvania. The unknown isolates were identified by comparing their restriction fragment patterns with 18 isolates of known Armillaria species common to the northeastern United States. Twenty of the unknown isolates (50%) were identified as either Armillaria gallica or Armillaria calvescens. Eighteen (46%) of the isolates were identified as Armillaria ostoyae. One isolate of Armillaria sinapina was obtained from a recently dead aspen tree. One isolate of Armillaria mellea, considered to be the most divergent of the Armillaria species, was obtained from basidiomes fruiting on a recently dead aspen tree near Berwick, Pennsylvania. In some instances, amplification of DNA was possible by adding mycelial scrapes directly to the polymerase chain reaction (PCR) mix, thus precluding the need for DNA extraction. Advancements in RFLP analysis may offer a method able to provide rapid and precise identification of most North American and European Armillaria isolates.
Effect of forest drainage on the peat bulk density of pine mires in Finland
Authors: Minkkinen Kari , Laine Jukka
Published: April 2011

Drainage of peatlands for forestry causes the water level to draw down, which results in subsidence of peat surface and increased peat bulk density (Db). Later on, an accelerated rate of organic matter decomposition and the pressure of the growing tree stand further compacts the peat. We measured the peat Db (0-80 cm) in 180 undrained and 209 drained (ca. 60-year-old) peatland sites representing three nutrient levels of pine fens and five macroclimatic regions from southern to northern Finland. Db was affected by climatic conditions, nutrient status, and the tree stand volume of the site. Db was significantly higher in drained than in undrained sites in all regions and site types: the mean (±SD) Db in the whole material was 82 ± 23 kg ·m-3 for the undrained sites and 133 ± 22 kg ·m-3 for the drained sites. The increase in Db was significant in all regions down to a depth of 60 cm and in southern Finland, even deeper than 80 cm. When the increase in carbon concentration was taken into consideration, the average postdrainage increase in the Db of the 0-80 cm layer equalled the amount of carbon in the 54-cm layer in average undrained peat. As the reported subsidences of peat surface in forest drainage areas in Finland are usually below this limit, the carbon storage of peat is likely to increase after drainage.