bluuebunny/crossref_metadata_2025 huggingface dataset:
Ring opening of α,β-epoxy phenyl ketones with ceric ammonium nitrate (CAN) and potassium bromide
Authors: Lu Zhou , Wu Wentao , Peng Lijun , Wu Longmin
Published: March 2008

Ring-opening reaction of α,β-epoxy phenyl ketones was achieved cooperatively using cerium ammonium nitrate (CAN) and potassium bromide. The reaction occurred regioselectively at the β-C to afford syn-β-bromo-α-hydroxyl ketones as main outcomes.Key words: ring-opening, epoxide, ceric ammonium nitrate, potassium bromide.
Bright blue luminescent pyrenyl-containing organosilicon compounds with contrasting charge transport functionality — SiPh2(p-C6H4-pyrenyl)(p-C6H4-N-benzimidazolyl) and SiPh2(p-C6H4-pyrenyl)[p-C6H4-NPh(1-naph)]
Authors: Bai Dongren , Han Shijin , Lu Zheng-Hong , Wang Suning
Published: March 2008

The authors investigated the impact of electron-transport and hole-transport functional groups on the properties and the performance of blue luminescent organosilicon compounds as bifunctional materials in organic light-emitting devices. Two new pyrenyl-containing organosilicon compounds, SiPh2(p-C6H4-pyrenyl)(p-C6H4-N-benzimidazolyl) (1) and SiPh2(p-C6H4-pyrenyl)[p-C6H4-NPh(1-naph)] (2) were synthesized. Both compounds display bright blue luminescence in solution and in the solid state with a high quantum efficiency, but they have contrasting electroluminescent properties. The presence of the benzimidazolyl group in 1 enables it to function as a bifunctional material (blue emitter and electron transporter) in OLEDs. An efficient triple-layer (CuPc/NPB/1) blue OLED (C.I.E. 0.15, 0.14) was fabricated successfully. The presence of the NPh(1-naph) group in 2 enables its use as an effective transparent hole injection material, but not a blue emitter in OLEDs.Key words: organosilicon compounds, synthesis, luminescence, electroluminescence, devices.
Highly selective oxidation of toluene using air over [Fe(III)TPP]Cl supported on chitosan
Authors: Huang Guan , Cai Chun-Cai , Luo Jin , Zhou Hong , Guo Yong-An , Liu Shang-Yue
Published: March 2008

The highly selective catalytic oxidation of toluene with air to benzaldehyde and benzyl alcohol in the liquid phase has been studied with the use of iron tetraphenylporphyrin (Fe TPP) supported on chitosan (CTS), (Fe TPP/CTS). The rates of toluene conversion and selectivity (aldehyde + alcohol) were subject to the reaction temperature, air pressure, and amount of iron tetraphenylporphyrin. By the use of the Fe TPP/CTS, containing 2 mg of iron tetraphenylporphyrin as catalyst, toluene oxidation with air under the optimum conditions of 190 °C and 0.6 MPa produced benzaldehyde and benzyl alcohol at 90% selectivity and 5.4% conversion of toluene, the mole turnover of the catalyst was about 6 × 106, and it could be reused efficiently for one more time. It is suggested that the amine groups (–NH2) on the chitosan chain act as a key assistor to the catalysis of Fe TPP for toluene oxidation. Compared with the conventional method of synthesizing benzaldehyde and benzyl alcohol, the new method has the advantages of reduced environmental pollution, higher selectivity for the two main products, and easy recovery of the catalyst.Key words: chitosan-supported iron porphyrin, catalysis, toluene oxidation, benzaldehyde, benzyl alcohol.
Historical range of variability in live and dead wood biomass: a regional-scale simulation study
Authors: Nonaka Etsuko , Spies Thomas A. , Wimberly Michael C. , Ohmann Janet L.
Published: March 2008

The historical range of variability (HRV) in landscape structure and composition created by natural disturbance can serve as a general guide for evaluating ecological conditions of managed landscapes. HRV approaches to evaluating landscapes have been based on age-classes or developmental stages, which may obscure variation in live and dead stand structure. Developing the HRV of stand structural characteristics would improve the ecological resolution of this coarse-filter approach to ecosystem assessment. We investigated HRV in live and dead wood biomass in the regional landscape of the Oregon Coast Range by integrating stand-level biomass models and a spatially explicit fire simulation model. We simulated historical landscapes of the region for 1000 years under pre-Euro-American settlement fire regimes and calculated biomass as a function of disturbance history. The simulation showed that live and dead wood biomass historically varied widely in time and space. The majority of the forests historically contained 500–700 Mg·ha–1 (50–70 kg·m–2) of live wood and 50–200 Mg·ha–1 (5–20 kg·m–2) of dead wood. The current distributions are more concentrated in much smaller amounts for both biomass types. Although restoring the HRV of forest structure is not necessarily a management goal for most landowners and managing agencies, departure from the reference condition can provide relative measure to evaluate habitat conditions for managers seeking to use forest structure as a means to maintain or restore ecosystem and species diversity.
Adding uncertainty to forest inventory plot locations: effects on analyses using geospatial data
Authors: Sabor Alexia A. , Radeloff Volker C. , McRoberts Ronald E. , Clayton Murray , Stewart Susan I.
Published: March 2008

The Forest Inventory and Analysis (FIA) program of the USDA Forest Service alters plot locations before releasing data to the public to ensure landowner confidentiality and sample integrity, but using data with altered plot locations in conjunction with other spatially explicit data layers produces analytical results with unknown amounts of error. We calculated the potential error from using altered location data in combination with other data layers that varied in mean map unit size. The incidence of errors associated with the use of altered plot locations exhibited a strong inverse relationship to the mean map unit size of the other data sets used in the analyses. For a 30 m × 30 m resolution land cover map, plot misclassification rates ranged from 32% to 66%, whereas only 1%–10% of plots were misclassified for ecological subsection data (mean polygon size 9067 km2). Housing density data derived from the US Decennial Census (mean polygon size = 5.7 km2) represented an intermediate condition, with 5%–70% of data points misclassified when altered plot locations were used. These analyses demonstrate the impacts of altering FIA plot locations and represent an important step toward making the FIA database more helpful to a broad variety of end users.
Evaluating sample plot imputation techniques as input in forest management planning
Authors: Duvemo Karl , Barth Andreas , Wallerman Jörgen
Published: March 2008

Recent advances in the use of data from airborne laser scanners have produced results that are potentially useful for forest-management planning. In this study, the results from recently developed imputation techniques using laser scanner and satellite data were evaluated as input in a timber-oriented forestry planning context. Evaluation comprised a cost plus loss analysis in which the data cost for a specific method is added to the expected loss arising from nonoptimal forestry activities caused by erroneous forest descriptions. Forest data from sample plot imputations based on laser scanner data, satellite data, or a combination of both were available for 64 stands in southern Sweden. For comparison, sample plot field inventories of 5 and 10 plots were simulated for each stand. Different stand areas and real interest rates were tested. The best performing imputation method, using both laser scanner and satellite data, produced the lowest total cost plus loss in the smallest stands when using the highest interest rate. In all other cases, the sample plot methods performed better. Operative phase considerations, altering the original plan, would likely mitigate the effect of nonoptimal forest-management decisions, improving the competitiveness of the imputation methods. Further analysis should include such owner-specific considerations.
Carbon rentals and silvicultural subsidies for private forests as climate policy instruments
Authors: Uusivuori Jussi , Laturi Jani
Published: March 2008

A forest model with an endogenous growth description and age-class structure is applied to study the impacts of potential climate policy instruments on the carbon services of privately owned and managed forests. The model describes the behaviour of a utility-maximizing private nonindustrial landowner who optimizes consumption flow, harvest timing, and the intertemporal allocation of silvicultural investments. Two policy options, one in which the landowner is granted periodic carbon rental payments and one in which the government subsidizes the costs of silvicultural investments, are studied. The rules for when the policy measures have both intended and unintended effects are derived. Using numerical examples, we demonstrate that the effectiveness of both policy options depends on the age-class structure of forests when future carbon benefits are discounted. In that case, carbon rental payments are more effective for forests with old age-class structures, while silvicultural subsidies are more effective for forests with young age-class structures.
Plastic and adaptive response to weather events: a pilot study in a maritime pine tree ring
Authors: Sánchez-Vargas Nahum M. , Sánchez Leopoldo , Rozenberg Philippe
Published: March 2008

This work proposes a novel approach to describing intraring wood density characteristics as functions of annual weather events. This approach was tested using three different maritime pine clonal experiments, in which X-ray microdensitometry has revealed conspicuous within-ring patterns affecting most of the trees in 1996. This pattern has been interpreted as the variation of tree response to weather-controlled changes of water balance during the 1996 growing season. The level of tree response was estimated using an original norm of reaction obtained from the microdensity profiles. A 1996 site drought index profile was synchronized with the 1996 microdensity profile by pairing conspicuous points of abrupt change in both profiles (breakpoints). Regression of density breakpoints on drought breakpoints describes the norm of reaction of radial increment to water availability, and the plasticity of radial increment to changes in soil moisture is described by the slope of the regression. The slope showed moderate levels of genetic control that depended on the site and could potentially be used as criteria for the evaluation of tree adaptation to weather.
A chance constraint estimation approach to optimizing resource management under uncertainty
Authors: Bevers Michael
Published: March 2008

Chance-constrained optimization is an important method for managing risk arising from random variations in natural resource systems, but the probabilistic formulations often pose mathematical programming problems that cannot be solved with exact methods. A heuristic estimation method for these problems is presented that combines a formulation for order statistic observations with the sample average approximation method as a substitute for chance constraints. The estimation method was tested on two problems, a small fire organization budgeting problem for which exact solutions are known and a much larger and more difficult habitat restoration problem for which exact solutions are unknown. The method performed well on both problems, quickly finding the correct solutions to the fire budgeting problem and repeatedly finding identical solutions to the habitat restoration problem.
Reformulation of Rothermel’s wildland fire behaviour model for heterogeneous fuelbedsThis article is one of a selection of papers published in the Special Forum on the Fuel Characteristic Classification System.
Authors: Sandberg David V. , Riccardi Cynthia L. , Schaaf Mark D.
Published: March 2008

The Fuel Characteristic Classification System (FCCS) includes equations that calculate energy release and one-dimensional spread rate in quasi-steady state fires in heterogeneous but spatially-uniform wildland fuelbeds, using a reformulation of the widely used Rothermel fire spread model. This reformulation provides an automated means to predict fire behavior under any environmental conditions in any natural, modified, or simulated wildland fuelbed. The formulation may be used to compare potential fire behavior between fuelbeds that differ in time, space, or as a result of management, and provides a means to classify and map fuelbeds based on their expected surface fire behavior under any set of defined environmental conditions (i.e., effective wind speed and fuel moisture content). Model reformulation preserves the basic mathematical framework of the Rothermel fire spread model, reinterprets data from two of the original basic equations in his model, and offers a new conceptual formulation that allows the direct use of inventoried fuel properties instead of stylized fuel models. Alternative methods for calculating the effect of wind speed and fuel moisture, based on more recent literature, are also provided. This reformulation provides a framework for the incremental improvement in quantifying fire behaviour parameters in complex fuelbeds and for modeling fire spread.
Standing or downed dead trees — does it matter for saproxylic beetles in temperate oak-rich forest?
Authors: Franc Niklas
Published: March 2008

For conservation of forest biodiversity, dead wood in the form of logs, snags, or cut high stumps is sometimes left or created when forests are harvested. In Scandinavia, such dead wood usually comes from conifers. For forests in temperate regions, few studies have analysed composition and species richness of beetles using dead wood of oaks ( Quercus spp). In this study in southern Sweden, I examined the occurrence of saproxylic beetles trapped at lying (logs) and standing (snags) dead wood of European oaks ( Quercus robur L. and Quercus petraea (Mattuschka) Liebl.) in 13 oak-rich mixed forests of relatively high conservation value. The assemblage of beetles differed strikingly between the lying and standing dead wood. Traps on lying dead wood, compared to traps on standing dead wood, had more fungivores and fewer primary and secondary wood boring species. Of 94 species tested for individual substrate preferences, 48 showed prevalence for different trap/substrate types. Absolute species richness was significantly higher on logs than snags, but a smaller proportion of the snag substrate or snag beetles may have been sampled. For red-listed beetles, no differences in their species richness were detected among substrates. These results suggest that logs of dead oaks are valuable and that both snags and logs of oak should be retained and, if needed, created in forestry, such that they are continuously available in stands.
Response of high-elevation limber pine (Pinus flexilis) to multiyear droughts and 20th-century warming, Sierra Nevada, California, USA
Authors: Millar Constance I. , Westfall Robert D. , Delany Diane L.
Published: March 2008

Limber pine ( Pinus flexilis James) stands along the eastern escarpment of the Sierra Nevada, California, experienced significant mortality from 1985 to 1995 during a period of sustained low precipitation and high temperature. The stands differ from old-growth limber pine forests in being dense, young, more even-aged, and located in warmer, drier microclimates. Tree growth showed high interannual variability. Relative to live trees, dead trees over their lifetimes had higher series sensitivity, grew more variably, and had lower growth. Although droughts recurred during the 20th century, tree mortality occurred only in the late 1980s. Significant correlations and interactions of growth and mortality dates with temperature and precipitation indicate that conditions of warmth plus sustained drought increased the likelihood of mortality in the 1985–1995 interval. This resembles a global-change-type drought, where warming combined with drought was an initial stress, trees were further weakened by dwarf mistletoe ( Arceuthobium cyanocarpum (A. Nels. ex Rydb.) A. Nels.), and proximally killed by mountain pine beetle ( Dendroctonus ponderosae Hopkins). However, the thinning effect of the drought-related mortality appears to have promoted resilience and improved near-term health of these stands, which suffered no additional mortality in the subsequent 1999–2004 drought.
The impact of spatial heterogeneity on selection: a case study on Pinus pinaster breeding seedling orchards
Authors: Zas Rafael
Published: March 2008

Although failure to account for spatial autocorrelation has been dramatic in some forest progeny trials, little attention has been paid to how this issue may affect selections within the trials. The effects of spatial autocorrelation of height growth on the estimation of genetic gain and on the spatial distribution of the selected trees were studied in four Pinus pinaster Ait. progeny trials that were rogued using different selection methods and intensities. When selections are based on unadjusted original values, selected trees tend to be located in the best microsites and are unlikely to be the most genetically superior. This resulted in a loss of genetic gain that varied between 10% and 20% and sometimes exceeded 30%. Differences in the loss of gain among different selection methods and intensities were minor and followed no clear pattern. Selecting on the basis of a conventional model resulted in spatial patterns of the retained trees that were clearly aggregated in all cases. However, selections based on spatially adjusted data resulted in random spatial patterns, except with family selection because of the use of multiple-tree plots. Because clumping of the retained trees may seriously affect the quantity and quality of the seed crop, breeders are strongly encouraged to use appropriate spatial models for roguing breeding seedling orchards.
Growth response functions improved by accounting for nonclimatic site effects
Authors: O’Neill Gregory A. , Nigh Gordon , Wang Tongli , Ott Peter K.
Published: March 2008

Growth response functions (GRFs) that relate the growth of a population to the climate of the sites in which it is tested are gaining attention for their ability to predict impacts of climate change on tree growth. However, nonclimatic site to site variation introduces error into GRFs. Using data from a large lodgepole pine ( Pinus contorta Dougl. ex Loud.) provenance test in British Columbia and the Yukon, Canada, a technique is presented that accounts for the effect of nonclimatic variation in GRFs. The mean height of the “local” provenances at each test site was used to predict “site height” from site climate variables in multiple regression. Residuals from the site height equation provided an index of the nonclimatic effect for each site and were included as a covariate in quadratic GRFs that related provenance height at each test site to mean annual temperature at each test site. Inclusion of the nonclimatic index in the model resulted in a moderate or large displacement of GRFs for 25% of the provenances, while increasing mean R2values for 138 of 140 provenances and decreasing the root mean squared error for 113 of 140 provenances. These results suggest that inclusion of the nonclimatic index in GRF models could substantially affect height predictions for some provenances and reduce prediction error for most provenances.
Growth and nutrient dynamics of Douglas-fir seedlings raised with exponential or conventional fertilization and planted with or without fertilizer
Authors: Everett K. T. , Hawkins B. J. , Kiiskila S.
Published: March 2008

The effects of two operational nursery fertilization regimes on the growth and nutrient dynamics of Douglas-fir ( Pseudotsuga menziesii var. glauca (Beissn.) Franco) seedlings after planting were compared. Seedlings were grown in a nursery with nutrients added at a constant rate (conventional fertilization) or at a rate that increased exponentially by 2%·day–1 (exponential fertilization) and planted near Barriere and Victoria, British Columbia. At the time of planting, half of the conventionally fertilized seedlings were planted with slow-release fertilizer packets. Growth and nutrient allocation was observed for 2 years following planting. Although the exponential fertilization regime provided 25% more N in the nursery compared with the conventional fertilization regime, exponentially fertilized seedlings were smaller at the time of planting, did not differ significantly in foliar N concentration, and showed no lasting benefits in growth or nutrient allocation. Two years after planting, there were no significant differences between the conventional and exponential fertilization regimes in seedling height, root collar diameter, total dry mass, or whole-plant N concentration. Seedlings fertilized at the time of planting had greater height and dry mass on the Barriere site but not on the dry Victoria site and whole-plant N concentrations did not differ 2 years after planting.
Differences in growth and wood property traits in cloned Norway spruce (Picea abies)
Authors: Zubizarreta Gerendiain A. , Peltola H. , Pulkkinen P. , Jaatinen R. , Pappinen A. , Kellomäki S.
Published: March 2008

Volume growth has typically been used as a selection trait of prime importance in forest tree breeding. Less attention has been given to the genetic or phenotypic relationships between the growth or yield and wood density traits. In the above context, we aimed to investigate the phenotypic relationships among different growth, yield, and wood density traits of 20 Norway spruce ( Picea abies (L.) Karst.) clones grown in southeastern Finland, in order to identify whether a high growth rate was associated with low wood density in any of the clones. Compared with growth or yield traits, the wood density traits showed lower phenotypic variations. The phenotypic correlations between growth, yield, and wood density traits were, on average, from moderate to high, suggesting that selection for one trait would simultaneously affect the other traits. Compared with volume production, selection based on stem mass could be more profitable if a clonal stand is managed for pulpwood rather than mechanical wood processing and vice versa; whereas selection for overall wood density alone would reduce both the stem volume and stem mass. However, by compromising the gain or loss in wood density and stem volume, clones with high stem volume and a relatively high wood density could be found.
Relative role of understory and overstory in carbon and nitrogen cycling in a southern Appalachian spruce–fir forestAES Publication 7863. Utah Agricultural Experiment Station, Utah State University, Logan, Utah.
Authors: Moore P. T. , Van Miegroet H. , Nicholas N. S.
Published: March 2008

This study investigated aboveground pools and fluxes of biomass, carbon (C), and nitrogen (N) in the overstory and understory of a southern Appalachian red spruce ( Picea rubens Sarg.) – Fraser fir ( Abies fraseri (Pursh) Poir.) forest, following adelgid-induced fir mortality and spruce windthrow. Using fifty 20 m × 20 m plots, stratified by elevation (1700–1900 m), we estimated standing biomass and fluxes of all growth forms from periodic stand inventories (1998–2003), vegetation surveys, and existing or derived allometric equations. Total C and N pools and fluxes were calculated from plant- and tissue-specific C and N concentrations. Total aboveground biomass attained predisturbance values, ranging from 313 Mg·ha–1at the lower elevations to 204 Mg·ha–1at the upper elevations. Overstory biomass production (5650 kg·ha–1·year–1) and N uptake (11–15 kg·ha–1·year–1) exceeded earlier reported values, indicating forest recovery. Woody understory accounted for 3% of aboveground biomass, 10% of annual productivity, and 19% of total N uptake (∼7 kg·ha–1·year–1). Herbaceous vegetation, which comprised only 1% of total biomass, took up 18–21 kg N·ha–1annually, >50% of total ecosystem N uptake (37 kg·ha–1·year–1). This suggests that N-rich understory vegetation plays an important role in N cycling.
Inonotus tomentosus and the dynamics of unmanaged and partial-cut wet sub-boreal spruce–fir forests
Authors: Newbery J. E. (Ted) , Lewis Kathy J. , Walters Michael B.
Published: March 2008

For wet sub-boreal spruce–fir forests (white spruce ( Picea glauca (Moench) Voss) × Engelmann spruce ( Picea engelmannii Parry ex Engelm.) – subalpine fir ( Abies lasiocarpa (Hook.) Nutt.)) in east-central British Columbia, we asked (i) do compositional and structural dynamics differ for unmanaged (UN) and partial-cut (PC) (50% removal 45 years before measurement) forests and (ii) how does Inonotus tomentosus Fr. (Teng) affect these dynamics? Inonotus tomentosus infected stands had 17% less spruce basal area (P = 0.059) than uninfected stands, but PC did not exacerbate I. tomentosus effects. PC and UN had similar live tree density, but UN had lower dead tree density. In all stands, snag longevity was typically <32 years, and ~40 years was required for dead wood to reach decay stage 3 or greater. UN was characterized by variable severity disturbances averaging ~8% of the canopy per decade. Management implications include the following: (i) harvest systems designed to emulate small-scale disturbance could remove trees at 8% of the canopy per decade, varied spatiotemporally, (ii) emulating dead wood abundance with partial cutting may be difficult given the impacts of partial cutting on dead wood abundance, and (iii) forests with moderate levels of I. tomentosus should not respond differently to harvesting than uninfected forests and thus require no special management.
Wildland fire effects on understory plant communities in two fire-prone forests
Authors: Laughlin Daniel C. , Fulé Peter Z.
Published: March 2008

Our understanding of wildland fire effects on understory plant communities is limited because of a lack of repeated measurements before and after lightning-ignited fires. We examined vegetation responses to a surface fire in a ponderosa pine forest and a mixed-severity fire in a spruce–fir–aspen forest using before–after, control–impact (BACI) study designs. We hypothesized that the surface fire would stimulate plant species richness and minimally alter community composition, but that the mixed-severity fire would decrease richness and significantly alter composition. In ponderosa pine forests, total species richness and plant cover increased slightly because of annual and biennial forb and grass establishment in soils where duff layers were reduced by the surface fire. In spruce–fir–aspen forests, total species richness and plant cover were similar in burned and unburned forests after 2 years, although annual and biennial forbs and graminoids increased significantly in the burned area. Plant community composition was altered by both fires. Wildfires may indirectly influence the understory plant community through the mediating effects of overstory basal area and litter depth. Fire effects on plant species richness and cover were weaker than effects due to environmental factors. Managers should anticipate increases in both native and non-native ruderal species following landscape-scale fires.
Hydraulic limitations and water-use efficiency in Pinus pinaster along a chronosequence
Authors: Magnani Federico , Bensada Abdelkader , Cinnirella Sergio , Ripullone Francesco , Borghetti Marco
Published: March 2008

Hydraulic constraints to water transport and water-use efficiency were studied in a Pinus pinaster Ait. chronosequence in Italy, consisting of four even-aged stands ranging from young (10 years old) to mature (75 years old), to explore the mechanisms involved in the decline of stand productivity as tree grow taller. Leaf-specific transpiration was estimated from sapflow rates measured by the heat dissipation technique, leaf-specific hydraulic conductance was computed from the slope of the relationship between transpiration and leaf water potential, long-term water-use efficiency was estimated from carbon isotope discrimination (Δ13C) in xylem cores, and photosynthetic capacity was assessed from CO2 assimilation/CO2 intercellular concentration curves. Leaf-specific transpiration decreased with stand development, suggesting a reduction in stomatal conductance, and a negative relationship was found between leaf-specific hydraulic conductance and tree height, suggesting a role of hydraulic constraints in the decline of current annual increment. Minimum daily leaf water potential did not change with stand height, suggesting that homeostasis in leaf water potential is achieved through a reduction in leaf transpiration. The Δ13C values increased with stand development, indicating a decline of water-use efficiency. Leaf level stomatal conductance was higher in the younger stand; no significant difference in maximum carboxylation rate was found among stands.
Comparing power among three sampling methods for monitoring forest vegetation
Authors: Johnson Sarah E. , Mudrak E. L. , Beever E. A. , Sanders S. , Waller D. M.
Published: March 2008

We compared three methods of sampling forest vegetation for their ability to reliably estimate changes in species richness, plant abundance, and overstory basal area and composition. Methods include the US Forest Service’s Forest Inventory and Analysis (FIA) method and two other methods being considered for use in monitoring National Parks in the Northern Great Lakes ecoregion. All methods were successful at detecting changes in composite variables but lacked sufficient enough power to detect a 20% change in the abundance of most individual species. All three methods had high power for detecting changes in overstory tree communities but differed greatly in their ability to track shifts in understory composition and diversity. Although complete walk-through surveys of all species present provided adequate power for tracking changes in diversity, sampling only 12 ground layer quadrats limited the power of the FIA method. Methods that sample the understory more intensively provide a better balance of sampling effort and provide higher power to detect changes in forest understory communities. Aggregating data across sites of similar habitat also provides more powerful estimates of change.
Boreal forest provenance tests used to predict optimal growth and response to climate change. 1. Jack pine
Authors: Thomson Ashley M. , Parker William H.
Published: March 2008

Height, diameter, and survival data were obtained from 16 rangewide jack pine provenance trials in eastern Canada and the United States. Climate data for each seed source and test location were used to relate height growth to 72 climate variables. Population response functions based on August minimum and January maximum temperatures were developed to predict climate values maximizing height growth for individual seed sources. Site transfer functions based on March precipitation and December minimum temperature were developed to predict climate values maximizing height growth for test locations. Contour lines representing optimal performance were fitted to current (1971–2000) and future (2041–2070) climate grids. Optimal growth is currently achieved between 46°N and 47°N latitude for most seed sources. Future temperature increases are expected to cause a northward shift of the optimal habitat by approximately 2°. Northern sources are growing at temperatures below optimum and would benefit from warmer environments provided other environmental factors do not become limiting. Central sources are growing at close to optimum and will be negatively affected by increased temperatures in the future. Southern sources performed better in cooler environments, and warmer temperatures may cause significant height growth loss and the potential extirpation of these populations.
Effects of time since stand-replacing fire and overstory composition on live-tree structural diversity in the boreal forest of central Canada
Authors: Brassard Brian W. , Chen Han Y.H. , Wang Jian R. , Duinker Peter N.
Published: March 2008

Stand structure diversity is hypothesized (i) to increase with stand development and (ii) to be greater in mixedwood stands than in conifer and broadleaf stands. We examined the effects of time since stand-replacing fire (TSF) and overstory type on stand volume, stand density, and tree-size variability, which is measured using Shannon’s diversity index (H′) and coefficient of variation, in fire-origin boreal forest stands. We sampled 36 stands representing conifer, mixedwood, and broadleaf overstory types, ranging in ages from 72 to 201 years TSF on upland mesic sites in northwestern Ontario, Canada. Stand volume decreased in older mixedwood and broadleaf stands, but followed a U-shaped pattern in conifer stands with TSF. Diameter-at-breast-height-based H′ followed an inverse U-shaped pattern with TSF for all overstory types. Height-based H′ decreased with TSF in conifer and mixedwood stands but peaked at the intermediate age class in broadleaf stands. Diameter-at-breast-height- and height-based coefficient of variation indices followed an inverse U-shaped distribution with TSF. Our results partially supported the two hypotheses, as (i) the 124- to 139-year-old stands were most diverse and (ii) mixedwood stands were more than or as equally diverse as conifer and broadleaf stands, depending on stand development stage and the diversity indices used.
Effect of fertilization and genetic variation on susceptibility ofPinus radiataseedlings toHylobius abietisdamage
Authors: Zas Rafael , Sampedro Luis , Moreira Xoaquín , Martíns Patricia
Published: March 2008

The effects of establishment fertilization and pine genotype on pine weevil ( Hylobius abietis L.) damage was studied in a radiata pine ( Pinus radiata D. Don) naturally infected family × fertilization genetic trial in Galicia (northwestern Spain). Fertilization strongly increased both growth and H. abietis damage, especially when calcium phosphate was included in the fertilization treatment. Fertilized plants showed higher degree of debarking, greater leader loss, and higher mortality than unfertilized controls. Because of the greater leader loss, fertilization did not significantly increase the actual height (height of live stem) 1 year after planting. In contrast, after the second growing season, fertilized plants overcompensated for the weevil damage and reached greater height than the unfertilized controls. However, considering the effects on survival and the stem deformities resulting from the leader losses, fertilization should be avoided (or delayed) in P. radiata plantations on clear-cut coniferous areas if the risk of H. abietis is high. Our results also indicate a strong genetic variation in H. abietis susceptibility within the Galician P. radiata breeding population. The high family-mean and the moderate individual-tree heritability estimates suggest that improving resistance to this pest by conventional breeding techniques is possible. The use of planting stock with improved resistance should be considered as another prophylactic measure to supplement the traditional methods employed against this pest.
On the budget for national environmental objectives and willingness to pay for protection of forest land
Authors: Boman Mattias , Norman Johan , Kindstrand Claes , Mattsson Leif
Published: March 2008

A number of national environmental objectives have been decided on by the Swedish parliament. In this paper, a measure of willingness to pay for attaining these objectives is outlined in terms of an “environmental budget”, which can be disaggregated. Based on a nationwide contingent valuation survey, the average environmental budget was estimated and then disaggregated on specific “green” indicators. This paper focuses especially on protection of forest land for biodiversity purposes. Multiple bounded dichotomous choice questions were employed in the survey, allowing respondents to express uncertainty in their valuations. The effect of different question formats and valuation scenarios on the disaggregation of the environmental budget was investigated. Consideration of uncertainty had a significant impact on willingness to pay estimates. Willingness to pay varied between different levels of forest land protection when uncertainty was explicitly introduced. When valuation estimates were aggregated on the national level, the value of forest land protection exceeded the costs by a small margin.
Site index in agroforestry systems: age-dependent and age-independent dynamic diameter growth models forQuercus ilexin Iberian open oak woodlands
Authors: Gea-Izquierdo G. , Cañellas I. , Montero G.
Published: March 2008

Despite Quercus ilex L. being one of the most widespread tree species in the Mediterranean basin, there are no growth models in the literature for this species. In this study, we compare age-dependent and age-independent dynamic diameter growth models and discuss the concept of dominance in open stands. A posteriori dominance was determined to fit potential age-dependent growth models and a site index based on diameter growth was defined. Formulations derived from power decline base models (Korf and Hossfeld) best described diameter growth. The best approach for age-dependent models was a polymorphic and with variable asymptotes generalized algebraic difference approach formulation. Residual errors in trees between 20 and 55 cm ranged from ~7.0% in potential growth models to ~15% in age-independent models expanded by density. Using a unique age-dependent dynamic equation for all trees, regardless of dominance, did not increase the error very much. In age-independent models, the inclusion of the defined site index reduced the prediction error but requires that the age of trees is estimated to determine the site index. The difficulty of estimating Q. ilex age makes age-independent models very attractive for system modelling. Age-independent models could be useful in other ecosystems where age estimation is problematic.
Using fuel and weather variables to predict the sustainability of surface fire spread in maritime pine stands
Authors: Fernandes Paulo M. , Botelho Hermínio , Rego Francisco , Loureiro Carlos
Published: March 2008

Thresholds for surface fire spread were examined in maritime pine ( Pinus pinaster Ait.) stands in northern Portugal. Fire sustainability was assessed after ignition of 2 m fire lines or in larger burns conducted in 10–15 m wide plots. The experiments were carried out from November to June in three fuel types: litter, litter plus shrubs, and litter with a nonwoody understorey. Moisture content of fine dead fuels, on-site weather variables, and descriptors of the fuel complex all had a highly significant influence on the probability of self-sustaining fire spread. A logistic model based solely on fuel moisture content correctly classified the fire sustainability status of 88% of the observations. Nonetheless, the subjectivity of the moisture of extinction concept was apparent, and further accuracy was achieved by the consecutive addition of fire spread direction (forward or backward), fuel type, and ambient temperature. Fully sustained fire spread, in opposition to marginal burns with broken fire fronts, was similarly dependent on fuel moisture but was affected also by fire spread direction and time since rain. The models can benefit fire research and fire management operations but can be made more practical if integrated in a fire danger rating system.
Potential change in lodgepole pine site index and distribution under climatic change in Alberta
Authors: Monserud Robert A. , Yang Yuqing , Huang Shongming , Tchebakova Nadja
Published: March 2008

We estimated the impact of global climate change on lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) site productivity in Alberta based on the Alberta Climate Model and the A2 SRES climate change scenario projections from three global circulation models (CGCM2, HADCM3, and ECHAM4). Considerable warming is apparent in all three models. On average, the increases in mean GDD5 (growing degree-days >5 °C) are 18%, 38%, and 65% by the 2020s, 2050s, and 2080s, respectively. Change in precipitation is essentially nil. This results in proportional increases in dryness index. We used the dryness index to predict the potential future range and GDD5 to predict its potential productivity. Generally, lodgepole pine site index is predicted to increase steadily by 3 m for each 30-year period. Offsetting this increase is a large reduction in suitable area as drying increases. At first, the warming increases the potential range up to 67% by the 2020s but then shrinks from 34% to 58% of its current area by 2080. Such major changes will need to be considered when setting long-term forest management plans. The increased risk of both wildfire and insect outbreaks further compounds this planning problem, especially because these disturbance events can interact and further increase risk.
Quantifying physical characteristics of wildland fuels using the Fuel Characteristic Classification SystemThis article is one of a selection of papers published in the Special Forum on the Fuel Characteristic Classification System.
Authors: Riccardi Cynthia L. , Prichard Susan J. , Sandberg David V. , Ottmar Roger D.
Published: March 2008

Wildland fuel characteristics are used in many applications of operational fire predictions and to understand fire effects and behaviour. Even so, there is a shortage of information on basic fuel properties and the physical characteristics of wildland fuels. The Fuel Characteristic Classification System (FCCS) builds and catalogues fuelbed descriptions based on realistic physical properties derived from direct or indirect observation, inventories, expert knowledge, inference, or simulated fuel characteristics. The FCCS summarizes and calculates wildland fuel characteristics, including fuel depth, loading, and surface area. Users may modify fuelbeds and thereby capture changing fuel conditions over time and (or) under different management prescriptions. Fuel loadings from four sample fuelbed pairs (i.e., pre- and post-prescribed fire) were calculated and compared by using FCCS to demonstrate the versatility of the system and how individual fuel components, such as shrubs, nonwoody fuels, woody fuels, and litter, can be calculated and summarized. The ability of FCCS to catalogue and summarize complex fuelbeds and reflect dynamic fuel conditions allows calculated results to be used in a variety of applications including surface and crown fire predictions, carbon assessments, and wildlife habitat management.
First Nations, forest lands, and “aboriginal forestry” in Canada: from exclusion to comanagement and beyond
Authors: Wyatt Stephen
Published: March 2008

The term “aboriginal forestry” is used increasingly to describe the evolving role of First Nations peoples in Canadian forestry over the last 30 years. This paper reviews a diversity of experiences and identifies issues that have important implications for governments, forest planners, and First Nations: a forestry regime that reflects the interests of governments and industry rather than those of First Nations; variable implementation of aboriginal rights in forestry practice; benefits and problems of economic partnerships; limitations on consultation, traditional knowledge, and comanagement in forestry; and finally, different forestry paradigms. Among these experiences and issues, we recognise different visions for the participation of First Nations peoples in Canadian forestry. At one end of the spectrum, “forestry excluding First Nations” is no longer accepted. The most common form may be “forestry by First Nations,” representing a role for First Nations within existing forestry regimes. Other options include “forestry for First Nations,” in which forest managers seek to incorporate aboriginal values and knowledge in management activities and “forestry with First Nations,” in which aboriginal peoples are equal partners in forest management. However, aboriginal forestry is better understood as a potential new form of forestry that uses knowledge and techniques drawn from both traditions and conventional forestry and is based on aboriginal rights, values, and institutions.
Plastid Evolution
Authors: Gould Sven B. , Waller Ross F. , McFadden Geoffrey I.
Published: March 2008

The ancestors of modern cyanobacteria invented O2-generating photosynthesis some 3.6 billion years ago. The conversion of water and CO2 into energy-rich sugars and O2 slowly transformed the planet, eventually creating the biosphere as we know it today. Eukaryotes didn't invent photosynthesis; they co-opted it from prokaryotes by engulfing and stably integrating a photoautotrophic prokaryote in a process known as primary endosymbiosis. After approximately a billion of years of coevolution, the eukaryotic host and its endosymbiont have achieved an extraordinary level of integration and have spawned a bewildering array of primary producers that now underpin life on land and in the water. No partnership has been more important to life on earth. Secondary endosymbioses have created additional autotrophic eukaryotic lineages that include key organisms in the marine environment. Some of these organisms have subsequently reverted to heterotrophic lifestyles, becoming significant pathogens, microscopic predators, and consumers. We review the origins, integration, and functions of the different plastid types with special emphasis on their biochemical abilities, transfer of genes to the host, and the back supply of proteins to the endosymbiont.
Inhibition of Multiple Vascular Endothelial Growth Factor Receptors (VEGFR) Blocks Lymph Node Metastases but Inhibition of VEGFR-2 Is Sufficient to Sensitize Tumor Cells to Platinum-Based Chemotherapeutics
Authors: Sini Patrizia , Samarzija Ivana , Baffert Fabienne , Littlewood-Evans Amanda , Schnell Christian , Theuer Andreas , Christian Sven , Boos Anja , Hess-Stumpp Holger , Foekens John A. , Setyono-Han Buddy , Wood Jeanette , Hynes Nancy E.
Published: March 2008

Vascular endothelial growth factor receptors (VEGFR) have important roles in cancer, affecting blood and lymphatic vessel functionality as well as tumor cells themselves. We compared the efficacy of a VEGFR tyrosine kinase inhibitor, PTK787/ZK222584 (PTK/ZK), which targets the three VEGFRs, with blocking antibodies directed against VEGFR-2 (DC101) or VEGF-A (Pab85618) in a metastatic melanoma model. Although all inhibitors exerted comparable effects on primary tumor growth, only PTK/ZK significantly reduced lymph node metastasis formation. A comparable decrease in lymphatic vessel density following blockade of VEGFR-2 (DC101) or the three VEGFRs (PTK/ZK) was observed in the metastases. However, the functionality of lymphatics surrounding the primary tumor was more significantly disrupted by PTK/ZK, indicating the importance of multiple VEGFRs in the metastatic process. The antimetastatic properties of PTK/ZK were confirmed in a breast carcinoma model. B16/BL6 tumor cells express VEGF ligands and their receptors. Blockade of a VEGFR-1 autocrine loop with PTK/ZK inhibited tumor cell migration. Furthermore, the tumor cells also showed enhanced sensitivity to platinum-based chemotherapy in combination with PTK/ZK, indicating that autocrine VEGFRs are promoting tumor cell migration and survival. In summary, our results suggest that, in addition to blocking angiogenesis, combined inhibition of the three VEGFRs may more efficiently target other aspects of tumor pathophysiology, including lymphatic vessel functionality, tumor cell dissemination, survival pathways, and response to chemotherapeutic compounds. [Cancer Res 2008;68(5):1581–92]