bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil and lodgepole pine foliar responses to two fertilizer sulphur forms in the Sub-Boreal Spruce zone, central interior British Columbia
Authors: Sanborn P T , Prietzel J , Brockley R P
Published: November 2005

Sulphur (S) fractions, total nitrogen (N) concentrations, and cumulative net S mineralization of forest floors and surface mineral soils (0-20 cm) were measured 13 years after an S-deficient lodgepole pine (Pinus contorta var. latifolia Engelm.) stand was fertilized (100 kg S·ha1 + 400 kg N·ha1) in 1990. Fertilizer treatments compared two S sources: elemental S (S0) and ammonium sulphate (AS). Total S and ester sulphate-S (SO4-S) concentrations and cumulative net S mineralization in forest floors were significantly higher in the S0 treatment than in the control and AS treatment. Except for a slight elevation of extractable SO4-S, such differences were absent in the mineral soils. Total S and SO4-S concentrations in current-year (2002) pine foliage from the S0 treatment were significantly higher than in foliage from the control and AS treatment, while foliar N concentrations indicated that all treatments had caused a return to N-deficiency. These results indicate that prolonged amelioration of S deficiencies in lodgepole pine stands in central interior British Columbia may be possible with single applications of S0.
An evaluation of the simulated annealing algorithm for solving the area-restricted harvest-scheduling model against optimal benchmarks
Authors: Crowe Kevin A , Nelson J D
Published: November 2005

A common approach for incorporating opening constraints into harvest scheduling is through the area-restricted model. This model is used to select which stands to include in each opening while simultaneously determining an optimal harvest schedule over multiple time periods. In this paper we use optimal benchmarks from a range of harvest scheduling problem instances to test a metaheuristic algorithm, simulated annealing, that is commonly used to solve these problems. Performance of the simulated annealing algorithm was assessed over a range of problem attributes such as the number of forest polygons, age-class distribution, and opening size. In total, 29 problem instances were used, ranging in size from 1269 to 36 270 binary decision variables. Overall, the mean objective function values found with simulated annealing ranged from approximately 87% to 99% of the optima after 30 min of computing time, and a moderate downward trend of the relationship between problem size and solution quality was observed.
Forest-floor chemical properties are altered by clear-cutting in boreal mixedwood forest stands dominated by trembling aspen and white spruce
Authors: Hannam K D , Quideau S A , Kishchuk B E , Oh S -W , Wasylishen R E
Published: November 2005

Alterations in the chemical properties of the forest floor following clear-cut harvesting may have implications for forest productivity in boreal stands. We used proximate analysis, carbon-13 (13C) isotopic determination, and cross-polarization, magic-angle spinning (CPMAS) 13C nuclear magnetic resonance (NMR) spectroscopy to examine differences in the characteristics of the forest floors from uncut stands and clear-cut stands dominated by white spruce (Picea glauca (Moench) Voss; SPRUCE) and trembling aspen (Populus tremuloides Michx.; ASPEN) in northern Alberta. Proximate analysis revealed no difference in the chemical properties of forest floors from clear-cut and uncut stands in either stand type, but the acid-insoluble residue of forest floors from clear-cut ASPEN stands was enriched in 13C compared with those from uncut ASPEN stands. CPMAS 13C NMR spectroscopy revealed that forest floors from clearcuts were enriched in total aromatic C, particularly in ASPEN stands, and depleted in phenolic C, particularly in SPRUCE stands. These patterns indicate that forest floors from the clearcuts have become more humified, which may reflect stand-type differences in the amount of labile C available to the forest-floor microbial community and reductions in above- and below-ground inputs to the forest floor following clear-cutting in both stand types. Changes in the chemical properties of forest floors from clear-cut SPRUCE and ASPEN stands could exacerbate C limitation in these soils and alter patterns of nutrient cycling.
Rate and causes of decline of mature and overmature balsam fir and spruce stands in New Brunswick, Canada
Authors: Taylor Sarah Lesley , MacLean David A
Published: November 2005

Data from 585 balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea spp.) permanent sample plots (PSPs) >50 years old in New Brunswick, Canada, measured between 1987 and 1998, were used to quantify the timing, magnitude, and causes of decline in stand growth, measured as negative net volume increment. Plots were subdivided into classes based on species group, ecoregion, and volume-development pattern (decreasing, fluctuating, stable, or increasing volume with time). Decline began at an earlier age in balsam fir  spruce (BFSP) PSPs (~70 years old) than in spruce  balsam fir (SPBF) PSPs (~120 years). One-third of plots (29%) fell into the decreasing volume-development category. Variation in the proportion of decreasing plots occurred among ecoregions (range 0%60%) and, to a lesser extent, among species groups (26%33%). Decreasing BFSP plots exhibited double the rate of volume loss of their SPBF counterparts (7.4 and 3.9 m3·ha1·year1, respectively). Decline was caused by an increased rate of mortality, which was highest in the decreasing volume-development classes (7.5 m3·ha1·year1) and lowest in the increasing volume-development classes (1.4 m3·ha1·year1). Growth of surviving trees remained relatively stable (2.54.2 m3·ha1·year1) among volume-development classes. Blowdown was the biggest cause of tree mortality, accounting for approximately 50% of dead trees in BFSP and SPBF plots. The rate of mortality was influenced by ecoregion, species, and the combined effect of previous insect-outbreak and wind disturbances.
Development and evaluation of an automated tree detectiondelineation algorithm for monitoring regenerating coniferous forests
Authors: Pouliot D A , King D J , Pitt D G
Published: November 2005

An algorithm is presented for automated detectiondelineation of coniferous tree regeneration that combines strategies of several existing algorithms, including image processing to isolate conifer crowns, optimal image scale determination, initial crown detection, and crown boundary segmentation and refinement. The algorithm is evaluated using 6-cm pixel airborne imagery in operational regeneration conditions typically encountered in the boreal forest 510 years after harvest. Detection omission and commission errors as well as an accuracy index combining both error types were assessed on a tree by tree basis, on an aggregated basis for each study area, in relation to tree size and the amount of woody competition present. Delineation error was assessed in a similar manner using field-measured crown diameters as a reference. The individual tree detection accuracy index improved with increasing tree size and was >70% for trees larger than 30 cm crown diameter. Crown diameter absolute error measured from automated delineations was <23%. Large crown diameters tended to be slightly underestimated. The presence of overtopping woody competition had a negligible effect on detection accuracy and only reduced estimates of crown diameter slightly.
Response of annual growth ring components to soil moisture deficit in young, plantation-grown Douglas-fir in coastal British Columbia
Authors: Bower Andrew D , Adams W Thomas , Birkes David , Nalle Darek
Published: November 2005

The response of 10 annual growth ring variables to drought in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) was examined using 16- and 17-year-old trees growing in six progeny test sites in southwestern British Columbia. Width, density, and mass components of individual rings common to the same 11-year period were measured on 16 trees at each site using X-ray densitometry of increment cores. For each ring variable and site, the slope of the linear regression of the annual ring component (after adjusting for age trends across the core) on the log of the total growing season soil moisture deficit (SMD) for the same year was used to derive a drought response coefficient (DRC). DRCs quantified the sensitivity of ring components to changing annual moisture conditions across the 11 years on a particular site. SMD appeared to materially influence ring variables on only the driest of the six sites where mean SMD was two to three times greater than at any other site. On this site, DRCs of eight growth ring variables were significantly (p < 0.05) related to SMD. On the remaining sites only six of a total of 50 DRCs were significantly different from zero. These results suggest that the response of annual growth ring variables to drought may be useful for assessing drought hardiness of genotypes in Douglas-fir breeding programs, but only on sites where average SMD is high enough to elicit a drought response.
Stratified forest inventory estimation with mapped plots
Authors: Van Deusen Paul C
Published: November 2005

Weighted estimation formulas are developed for producing stratified estimates of means and variances where data come from plots that can contain multiple forest conditions. Each plot is mapped to allow the analyst to focus on specific forest types or conditions. The weights required to accommodate mapped plots are somewhat more complicated than the weights for unmapped plots. In particular, these weights depend on the mapped condition of interest. The implication is that a single plot weight or expansion factor will not suffice for all analyses as it does for unmapped plots. The methods are demonstrated using USDA Forest Service inventory data.
Foraging patterns of pileated woodpeckers in a managed Acadian forest: a resource selection function
Authors: Lemaître Jérôme , Villard Marc-André
Published: November 2005

We analyzed the relative influence of foraging substrate characteristics as predictors of the probability of use by the pileated woodpecker (Dryocopus pileatus L.) and determined threshold values for significant predictors. We sampled used and available substrates around 126 stations distributed in an intensively managed forest in northwestern New Brunswick, Canada. We developed a resource selection function (RSF), validated by a resampling procedure, and compared selection ratios for significant predictors. Diameter at breast height (DBH) of trees and snags was the most significant predictor, probably reflecting nesting selection by its main prey, carpenter ants (Camponotus spp.). The pileated woodpecker preferred deciduous substrates with DBH >35 cm and coniferous substrates with DBH >30 cm. Among deciduous substrates, it preferred snags over living trees, but there was no such preference for coniferous substrates. American beech (Fagus grandifolia Ehrh.) was clearly preferred over all other species. The RSF we developed and the thresholds we obtained should help forest managers and conservation planners assess habitat quality for this keystone species.
Predicting forest growth and yield in northeastern Ontario using the process-based model of TRIPLEX1.0
Authors: Zhou Xiaolu , Peng Changhui , Dang Qing-Lai , Chen Jiaxin , Parton Sue
Published: November 2005

Process-based carbon dynamic models are rarely validated against traditional forest growth and yield data and are difficult to use as a practical tool for forest management. To bridge the gap between empirical and process-based models, a simulation using a hybrid model of TRIPLEX1.0 was performed for the forest growth and yield of the boreal forest ecosystem in the Lake Abitibi Model Forest in northeastern Ontario. The model was tested using field measurements, forest inventory data, and the normal yield table. The model simulations of tree height and diameter at breast height (DBH) showed a good agreement with measurements for black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), and trembling aspen (Populus tremuloides Michx.). The coefficients of determination (R2) between simulated values and permanent sample plot measurements were 0.92 for height and 0.95 for DBH. At the landscape scale, model predictions were compared with forest inventory data and the normal yield table. The R2 ranged from 0.73 to 0.89 for tree height and from 0.72 to 0.85 for DBH. The simulated basal area is consistent with the normal yield table. The R2 for basal area ranged from 0.82 to 0.96 for black spruce, jack pine, and trembling aspen for each site class. This study demonstrated the feasibility of testing the performance of the process-based carbon dynamic model using traditional forest growth and yield data and the ability of the TRIPLEX1.0 model for predicting growth and yield variables. The current work also introduces a means to test model accuracy and its prediction of forest stand variables to provide a complement to empirical growth and yield models for forest management practices, as well as for investigating climate change impacts on forest growth and yield in regions without sufficient established permanent sample plots and remote areas without suitable field measurements.
Effects of climate, disturbance, and species on forest biomass across Russia
Authors: Krankina O N , Houghton R A , Harmon M E , Hogg EH (Ted) , Butman D , Yatskov M , Huso M , Treyfeld R F , Razuvaev V N , Spycher G
Published: November 2005

We used detailed forest inventory data from 43 forests (3.5 × 103  115.2 × 103 stands each) and meteorological data from 30 weather stations located in proximity to these forests to assess the effects of disturbance and climate on biomass accumulation patterns across the forest zone of Russia. Chronosequences of biomass accumulation following disturbance were developed for each of the two to five dominant tree species in each forest using stand survey data collected by forest inventories in different regions of Russia between 1986 and 2003. These chronosequences represent changes in average live biomass of forest stands between age 10 and 210 years at 10-year intervals. The correlation of attributes of biomass accumulation (i.e., maximum biomass, biomass at age 40, and maximum biomass increment) with climatic and disturbance attributes was significant but weak (adjusted R2 = 0.200.37). The effect of the most influential disturbance attributes (percent clear-cut and percent old forest) was as strong or stronger than the effect of climatic attributes (30-year averages of the sum of positive daily temperatures and climate moisture index). The effect of tree species was significant, but weaker than the effects of climate or disturbance. Combining climate, disturbance, and species attributes generally improved the models (adjusted R2 = 0.370.53). The patterns of biomass change observed in chronosequences are influenced by the tendency of harvesting to target more productive forest stands of commercially valuable species, creating a disparity in productivity among the age cohorts. The apparent link between disturbance attributes of forests and biomass accumulation patterms in forest stands may be used to improve broad-scale modeling of changes in forest biomass with remotely sensed data.
Response of boreal ecosystems to varying modes of permafrost degradation
Authors: Jorgenson M T , Osterkamp T E
Published: November 2005

Permafrost degradation associated with a warming climate is second only to wildfires as a major disturbance to boreal forests. Permafrost temperatures have risen to 4 °C since the “Little Ice Age”, resulting in widespread thawing of permafrost. The mode of permafrost degradation is highly variable, and its topographic and ecological consequences depend on the interaction of slope position, soil texture, hydrology, and ice content. We partitioned this variability into 16 primary modes: (1) thermokarst lakes from lateral thermomechanical erosion; (2) thermokarst basins after lake drainage; (3) thaw sinks from subsurface drainage of lakes; (4) glacial thermokarst of ice-cored moraines; (5) linear collapse-scar fens associated with shallow groundwater movement; (6) round isolated collapse-scar bogs from slow lateral degradation; (7) small round isolated thermokarst pits from surface thawing; (8) polygonal thermokarst mounds from advanced ice-wedge degradation; (9) mixed thermokarst pits and polygons from initial ice-wedge degradation; (10) irregular thermokarst mounds from thawing of ice-poor silty soils; (11) sinkholes and pipes resulting from groundwater flow; (12) thermokarst gullies and water tracks from surface-water flow; (13) thaw slumps related to slope failure and thawing; (14) thermo-erosional niches from water undercutting of ice-rich shores; (15) collapsed pingos from thawing of massive ice in pingos; and (16) nonpatterned ground from thawing of ice-poor soils. These modes greatly influence how thermokarst changes or disrupts the ground surface, ecosystems, human activities, infrastructure, and the fluxes of energy, moisture, and gases across the landair interface.
Fire effects on soil organic matter content, composition, and nutrients in boreal interior Alaska
Authors: Neff J C , Harden J W , Gleixner G
Published: November 2005

Boreal ecosystems contain a substantial fraction of the earth's soil carbon stores and are prone to frequent and severe wildfires. In this study, we examine changes in element and organic matter stocks due to a 1999 wildfire in Alaska. One year after the wildfire, burned soils contained between 1071 and 1420 g/m2 less carbon than unburned soils. Burned soils had lower nitrogen than unburned soils, higher calcium, and nearly unchanged potassium, magnesium, and phosphorus stocks. Burned surface soils tended to have higher concentrations of noncombustible elements such as calcium, potassium, magnesium, and phosphorus compared with unburned soils. Combustion losses of carbon were mostly limited to surface dead moss and fibric horizons, with no change in the underlying mineral horizons. Burning caused significant changes in soil organic matter structure, with a 12% higher ratio of carbon to combustible organic matter in surface burned horizons compared with unburned horizons. Pyrolysis gas chromatography  mass spectroscopy also shows preferential volatilization of polysaccharide-derived organic matter and enrichment of lignin- and lipid-derived compounds in surface soils. The chemistry of deeper soil layers in burned and unburned sites was similar, suggesting that immediate fire impacts were restricted to the surface soil horizon.
Biomass allocation and growth rates inPinus sylvestrisare interactively modified by nitrogen and phosphorus availabilities and by tree size and age
Authors: Portsmuth Angelika , Niinemets Ülo , Truus Laimi , Pensa Margus
Published: November 2005

Biomass allocation and growth of Scots pine, Pinus sylvestris L., of various sizes (height 0.0320 m) and ages (1151 years) were investigated in two infertile sites (raised bog and sand dunes) to determine relative nitrogen and phosphorus limitations on productivity and their interactions and size-dependent controls. Dry mass weighted average nitrogen (NW) and phosphorus (PW) contents were higher in P. sylvestris in sand dunes than in those in the raised bog, but PW/NWratios overlapped between the sites. Leaf dry mass ratio (FL) and leaf-area ratio (LAR) increased with NW, and FLincreased with PW. The relative growth rate (RG) was more strongly associated with PWthan with NW. The net assimilation rate per leaf dry mass (NARM) scaled positively with PWbut not with NW, demonstrating that the stronger effect of PWon growth was due to modified biomass allocation and physiology (RG = NARM× FL), while NWaffected growth via biomass allocation. Partitioning and growth characteristics were poorly related to the PW/NWratio. The overall decrease of growth in larger trees resulted from their lower LAR and FL. Increases in size further led to a lower NWbut higher PW. We conclude that optimum productivity at a given NWrequires a certain minimum PW, not a specific "non-limiting" PW/NWratio. While nutrients affect growth by changing biomass allocation and physiological activity, size primarily modifies biomass allocation.
Comparison of three sampling methods in the characterizationof cork oak stands for management purposes
Authors: Paulo Maria João , Tomé Margarida , Otten Albert , Stein Alfred
Published: November 2005

The cork oak (Quercus suber L.) is an evergreen oak that has the ability to produce a continuous layer of cork tissue which regenerates after being removed. Cork oak stands can be diverse in structure. Young stands are often regularly spaced, whereas older stands usually show clustering and can be mixed with other species. Farmers assessing cork value use a zigzag sampling procedure within a stand. In this study we compare zigzag sampling with two other sampling methods, fixed-radius plot sampling and n-tree distance sampling, using a model for the costs of sampling. We used data from two cork oak stands in Portugal as well as data from six types of simulated stands. We found that zigzag is the poorest sampling method, as in most situations it produces estimators with larger bias and larger standard errors than that produced by the other two procedures. Fixed-radius plot sampling and n-tree distance sampling produce comparable results; however, fixed-radius plot sampling is preferred because it produces unbiased estimators.
Tree growth and mortality after small-group harvesting in New Zealand old-growth Nothofagus forests
Authors: Wiser Susan K , Allen Robert B , Benecke Udo , Baker Gordon , Peltzer Duane
Published: November 2005

In New Zealand uncertainty about how silvicultural systems influence growth and mortality of residual beech trees has caused controversy surrounding sustainable beech management. We assess the impact of group-selection harvesting on residual-tree growth and mortality in old-growth hard beech (Nothofagus truncata (Col.) Ckn.) and mixed red beech  silver beech (Nothofagus fusca (Hook. F.) Oerst.  Nothofagus menziesii (Hook. F.) Oerst.) forests. Proximity to cuts had a major influence on growth that varied with both species and initial tree diameter. For all three beech species, diameter increment of small trees (<60 cm DBH) in intact forest was less than that of large trees, but smaller trees grew two- to four-fold faster along cut edges than in intact forest. In contrast, growth of large hard beech and silver beech and intermediate-sized red beech trees did not vary with cut proximity, suggesting that these main canopy trees were growing at a maximum potential rate. Edge trees were more likely to die as their level of Platypus beetle infection increased, but overall mortality rates were unrelated to harvest proximity. These results demonstrate that complex mortality and growth responses to harvesting should be incorporated into forest growth models upon which silvicultural systems that sustain the structural, compositional, and functional characteristics of forests are based.
The effects of UV-B, nitrogen fertilization, and springtime warming on sugar maple seedlings and the soil chemistry of two central Ontario forests
Authors: Sager Eric PS , Hutchinson T C
Published: November 2005

The interactive effects of springtime warming, ambient UV-B, and nitrogen fertilization on the chemistry of sugar maple (Acer saccharum Marsh.) seedlings and soils from two contrasting sites were assessed. Open-top chambers increased average springtime air temperatures by approximately 1.5 °C, but their heating effect was diminished upon closure of the overstory canopy. Ambient levels of UV-B were reduced with Mylar D polyester film. Ammonium nitrate fertilizer was added in an amount equivalent to an additional 50 kg N·ha1. The soils of the Oliver forest were deep luvisols overlying a strongly calcareous till (average pH 6.0), while the naturally acidic soils of Haliburton were derived from the Precambrian Shield (average pH 4.7). Of the three main treatments used in this study, application of nitrogen fertilizer had the greatest impacts on foliar chemistry. At both sites, fertilizer application increased the acidity of the soils, while at Haliburton there were losses in total soil calcium. Haliburton maple seedlings had increased foliar concentrations of aluminum and manganese, decreased concentrations of calcium, and reduced calcium/manganese and magnesium/manganese nutrient ratios, after fertilizer was applied. Meanwhile, seedlings growing on the more alkaline soils of Oliver had increased foliar concentrations of magnesium following application of the nitrogen fertilizer. We suggest that these changes in the elemental chemistry of the soils and foliage brought on by continued nitrogen loading may predispose seedlings growing on naturally acidic soils, such as those of the Precambrian Shield, to further stress from additional abiotic and biotic stressors.
Prediction of loblolly pine wood properties using transmittance near-infrared spectroscopy
Authors: Sykes Robert , Li Bailian , Hodge Gary , Goldfarb Barry , Kadla John , Chang H -m
Published: November 2005

Near-infrared (NIR) spectroscopy is a rapid nondestructive technique that has been used to characterize chemical and physical properties of a wide range of materials. In this study, transmittance NIR spectra from thin wood wafers cut from increment cores were used to develop calibration models for the estimation of α-cellulose content, average fiber length, fiber coarseness, and lignin content in the laboratory. Eleven-year-old trees from two sites were sampled using 12-mm increment cores. Earlywood and latewood of ring 3 and ring 8 from these samples were analyzed in the laboratory using microanalytical methods for α-cellulose content, average fiber length, fiber coarseness, and lignin content. NIR calibrations and laboratory measurements based on one site were generally reliable, with coefficients of determination (R2) ranging from 0.54 to 0.88 for average fiber length and α-cellulose content, respectively. Predicting ring 8 properties using ring 3 calibration equations showed potential for predicting α-cellulose content and fiber coarseness, with R2 values of approximately 0.60, indicating the potential for early selection. Predicting the wood properties using the calibration equations from one site to predict another showed moderate success for α-cellulose content (R2 = 0.64) and fiber coarseness (R2 = 0.63), but predictions for fiber length were relatively poor (R2 = 0.43). Prediction of lignin content using transmittance NIR spectroscopy was not as reliable in this study, partially because of low variation in lignin content in these wood samples and large errors in measuring lignin content in the laboratory.
Attributes of forest strips used by snowshoe hare in winter within clear-cut boreal landscapes
Authors: Potvin François , Bertrand Normand , Ferron Jean
Published: November 2005

The snowshoe hare (Lepus americanus Erxleben) is an important prey for many predators in the boreal forest. In this biome, clear-cut landscapes are generally large and consist of aggregated cutting blocks separated by narrow forest strips (typically 60100 m wide). To identify attributes of forest strips that are important for snowshoe hares, we measured the use of strips using track counts over two winters in six clear-cut landscapes (23256 km2) in south-central Quebec. Surveys were conducted in 20 riparian strips (RS), 20 upland strips (US), and 15 control sites (CO) at the periphery of clear-cut landscapes. Overall, 392 signs of hare presence were recorded along 50 km of transects. Snowshoe hares were present in one-third of the strips surveyed and were five times less abundant in US and RS than in CO. The species avoided strip edges. Hares were more common in the wider strips (>100 m), in the strips adjacent to residual forest patches (≥25 ha), or in those having a denser shrub canopy, which is often associated with a greater basal area in balsam fir (Abies balsamea (L.) Mill.). To maintain snowshoe hare at moderate densities in large clear-cut landscapes, we suggest leaving uncut forest strips >100 m wide in areas having a good shrub cover with presence of balsam fir.
Growth responses to commercial thinning in Douglas-fir stands with varying severity of Swiss needle cast in Oregon, USA
Authors: Mainwaring Douglas B , Maguire Douglas A , Kanaskie Alan , Brandt Jeff
Published: November 2005

Concern has risen about the degree to which Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands with severe infections of Swiss needle cast (SNC) respond to thinning. A retrospective study was established in the fall of 2001 to assess the growth of Douglas-fir stands that were commercially thinned between 4 and 10 years ago. Current SNC infection levels in these stands ranged from severe to very light. Past volume and basal area growth declined with increasing severity of SNC, as measured by current foliage retention and crown length / sapwood ratio. As has been observed in many other studies, thinning to lower residual stock reduced stand level growth; however, individual tree growth increased with lower residual stand density. The ratio of growth in successive periods and analysis of annual basal area growth since thinning suggested that trees did respond to thinning, although less so as SNC increased. A positive response to thinning, regardless of infection level, was confirmed by an analysis of annual trends in basal area growth over the first 5 years after thinning.
The physiological responses of oak seedlings to warm storage
Authors: Cabral Raquel , O'Reilly Conor
Published: November 2005

The effects of warm storage (15 °C) on the physiological responses and subsequent field performance of 2-year-old oak (Quercus robur L.) seedlings that had been cold (12 °C) stored until May were assessed. Shoot xylem pressure potential, shoot water content, shoot tip dry mass, root electrolyte leakage, and root growth potential were evaluated at regular intervals during the 21-day warm storage period. The date of lifting to cold storage had little effect on the physiological responses to warm storage. Root electrolyte leakage increased after 7 days of storage, despite the fact that root growth potential and survival were unaffected. Values then increased further before decreasing again by the end of the 21-day storage period to values similar to those recorded after 0 or 7 days of storage. Storage for up to 21 days greatly reduced root growth potential and shoot quality after planting in the field. The shoot xylem pressure potential of seedlings declined during the early stage of warm storage, but then increased to values similar to those recorded after cold storage. Shoot water content increased during the early storage period, then declined slightly, but values were higher after 21 days of storage than at the time of placement in warm storage. While most physiological responses fluctuated in a consistent manner, these changes were not necessarily predictable. Root growth potential was a good indicator of plant field performance potential, but the other physiological parameters were less useful to this end.
Seasonal precipitation in the south-central Helan Mountain region, China, reconstructed from tree-ring width for the past 224 years
Authors: Liu Yu , Cai Qiufang , Shi Jiangfeng , Hughes M K , Kutzbach J E , Liu Zhengyu , Ni Fenbiao , An Zhisheng
Published: November 2005

Chinese pine (Pinus tabulaeformis Carr.) trees from the Helan Mountain range in central China have been used to reconstruct total JanuaryJuly precipitation from AD 1775 to 1998. For the calibration period R2adj = 0.52. Narrow rings are associated with below-average precipitation from March through August. Wide rings are produced in years when the East Asian summer monsoon front arrives early. We use local historical writings over the last 300 years about extreme climatic conditions between spring and early summer to verify the extreme years. Most of the extreme dry years could be identified in local historical documents. Another East Asian summer monsoon front related precipitation reconstruction from northern Helan Mountain is also used to verify this reconstruction. They are well correlated from year to year, with a correlation coefficient of 0.52 (N = 218), and the wet or dry extreme events are well matched in many cases. This comparison could indicate a spatial and temporal connection of spring to early summer climatic conditions for the southern to northern portion of the Helan Mountain region. The sustained wet period before the 20th century lasts from the 1850s to the 1890s, and the longest dry period before the 20th century is in the 1830s and 1840s, largely coinciding with a springsummer drought in Kashmir. Overall, multiyear fluctuations, such as the spectacular large-scale drought of the late 1920s and droughts in the 1830s1840s and the 1970s, are well captured in this reconstruction, but only the 1970s drought is in the instrumental period. The reconstruction shows increasing variance from the 18th to the late 20th century.
Sizedensity metrics, leaf area, and productivity in eastern white pine
Authors: Innes J C , Ducey M J , Gove J H , Leak W B , Barrett J P
Published: November 2005

Sizedensity metrics are used extensively for silvicultural planning; however, they operate on biological assumptions that remain relatively untested. Using data from 12 even-aged stands of eastern white pine (Pinus strobus L.) growing in southern New Hampshire, we compared size-density metrics with stand productivity and its biological components, including leaf area index (LAI) and measures of crown morphology. Density indices included Reineke's stand density index (SDI), a 3/2 relative density law, and trees per hectare. We examined models with and without site index and stand age as components, to predict total stand accretion (PAI), LAI, and growth efficiency (GE). LAI was a strong linear predictor of PAI (R2 = 0.89). However, of the indices tested only SDI was a significant predictor of accretion, and none were significantly related to LAI or GE. Site index was not a significant predictor of any variable when used alone, but in combination with SDI and stand age did lead to significant relationships with PAI (R2 = 0.84), LAI (R2 = 0.67), and GE (R2 = 0.92). Of the density indices tested only trees per hectare was strongly correlated with crown attributes. These results demonstrate that size-density metrics combined with other stand attributes are reasonably correlated with biological measures of stand growth.
Inhibitory Effects of Selaginella tamariscina on Immediate Allergic Reactions
Authors: Dai Yue , But Paul Pui-Hay , Chu Lee-Man , Chan Yiu-Pong
Published: November 2005

The anti-allergic effects of a 70% ethanol extract from Selaginella tamariscina herb (EST) were evaluated in this study. EST given at the doses of 500 and 1000 mg/kg can inhibit mouse systemic anaphylactic shock induced by compound 48/80 in a dose-dependent manner. It can also dose-dependently block rat homologous passive cutaneous anaphylaxis and skin reactions caused by exogenous histamine and serotonin with a significant difference observed at the dose of 1000 mg/kg. In addition, EST can reduce histamine release from rat peritoneal mast cells triggered by compound 48/80 and an antigen in vitro. When incubated with rat mast cells, the extract (200 μg/ml) can significantly elevate the intracellular cAMP levels. The finding suggests that EST inhibits mast cell-dependent, immediate allergic reactions. Its effects appear to be mediated by reducing the release of vasoactive amines such as histamine from mast cells via stabilizing the cell membrane and weakening the inflammatory action of these amines. Based on these results, Selaginella tamariscina and one of its active components flavonoids may be useful as potential remedies for allergic rhinitis and other allergy-related diseases.
Acupuncture Reduces Alcohol Withdrawal Syndrome and c-Fos Expression in Rat Brain
Authors: Kim Ji Hyun , Chung Jin Yong , Kwon Young Kyu , Kim Kwang Joong , Yang Chae Ha , Hahm Dae-Hyun , Lee Hye-Jung , Pyun Kwang-Ho , Shim Insop
Published: November 2005

Acupuncture as a therapeutic intervention is widely practiced in the treatment of many functional disorders including alcohol abuse. In the present study, the effects of acupuncture on alcohol withdrawal syndrome (AWS) and Fos-like immunoreactivity (FLI) in the striatum and the nucleus accumbens (NAC) of rats were investigated. During 3 days of cessation following chronic administration of ethanol (3 g/kg, i.p. for 3 weeks), rats showed a significant increase in AWS, such as hypermotility, tail rigidity, grooming and tremor, and an increase in FLI in the dopamine terminal areas of the brain. Treatment with acupuncture at zusanli (ST36) or sanyinjiao (SP6) during the withdrawal period inhibited both AWS and FLI of rats undergoing ethanol injection. These results suggest that acupuncture may be useful in the treatment of alcoholism by modulating post-synaptic neural activation in the striatum and NAC.
Effects of the Extract of a Chinese HerbTripterygium wilfordiiHook f on Rat Pituitary Gland
Authors: Chen Long , Wang Huijun , Zhao Ziqin , Zhang Yihu , Huang Guangzhao
Published: November 2005

In China, the ethylacetate extract of the herb Tripterygium wilfordii Hook f (TWEE), containing the major active ingredient triptolide, is often used with favorable effect on rheumatoid arthritis patients, in alternation with the use of prednisone. The mechanism of this therapeutic effect, however, has not been completely delineated. In this study, we studied how TWEE and prednisone affect the pituitary and adrenal glands in rats. Thirty normal male Sprague-Dawley rats (ten per group) were randomly assigned to receive: (1) TWEE (25 mg/kg, twice a day), (2) prednisone (2 mg/kg, twice a day), or (3) vehicle (control) (0.5% sodium carboxymethyl cellulose 1 ml, twice a day), orally for 30 days. Pituitary and trunk blood were collected on day 31. Adrenocorticotropic hormone (ACTH) expression in the pituitary gland was assessed morphologically by immunohistochemical techniques. Plasma ACTH concentrations and serum corticosterone concentrations were quantitatively measured by radioimmunoassay. We found that TWEE significantly increased plasma ACTH concentration and serum corticosterone concentration and dramatically increased the number of ACTH-positive cells in the pituitary. Our findings indicate that TWEE can promote the synthesis and secretion of ACTH cells — in the pars distalis of the rat pituitary gland and the production of corticosterone in the zone fasciculata of the adrenal cortex. Our results indicate that TWEE has a cortical hormone-like function and can promote adrenal cortex function by activating the hypothalamus-pituitary-adrenal axis.
Anti-hypertension Effects of Traditional Chinese Medicine Ju-Ling-Tang on Renal Hypertensive Rats
Authors: Shih Hung-Che , Lee Tzu-Hsin , Chen Shu-Chen , Li Chien-Ying , Shibuya Takeshi
Published: November 2005

This research investigated the anti-hypertension effect of the traditional Chinese medicine (TCM) Ju-Ling-Tang (JLT) on an animal model of hypertension induced by unilateral renal artery ligation. In the study of anti-hypertension effects, 60 minutes after oral administration with NG tube feeding of 240 mg/kg JLT, a significant decrease in blood pressure ( p < 0.05) was observed and sustained till 120 minutes. In the group given 50 mg/kg α-methyldopa orally, the effect was obvious 90 minutes after medication ( p < 0.01), and lasted until 240 minutes. In terms of organ pathology, a significant reduction in the extent of induced glomerular sclerosis was observed in rats given 240 mg/kg JLT compared with the control. From these results, we infer that JLT has a beneficial anti-hypertensive effect on renal hypertension.
RADIATION REACTION AND QUANTUM DAMPED HARMONIC OSCILLATOR
Authors: KHEIRANDISH F. , AMOOSHAHI M.
Published: November 2005

By taking a Klein–Gordon field as the environment of a harmonic oscillator and using a new method for dealing with quantum dissipative systems (minimal coupling method), we find out the quantum dynamics and radiation reaction for a quantum damped harmonic oscillator. Applying perturbation method, we obtain some transition probabilities indicating the way energy flows between oscillator, reservoir and quantum vacuum.
BASE SEQUENCE EFFECTS ON CHARGE CARRIER GENERATION IN DNA: A THEORETICAL STUDY
Authors: STARIKOV E. B. , LEWIS J. P. , SANKEY O. F.
Published: November 2005

We have thoroughly analyzed the electronic structure of stacked DNA Watson–Crick (WC) base pair dimers using ab initio Hartree–Fock and semiempirical Hartree–Fock-configuration-interaction quantum chemistry. We consider all the possible base compositions and sequences at the nucleoside level in vacuo. The results show that in such systems charge carrier generation could in principle be possible via charge transfer excitons, which turn out to dominate the first excited electronic states of the WC base pairs and their stacked dimers, and this process is largely sequence- and conformation-dependent. Possible consequences of this result for polymeric DNA duplexes are discussed.
ITERATIVE ENTANGLEMENT DISTILLATION FOR FINITE RESOURCES
Authors: PROBST-SCHENDZIELORZ STEFAN , BSCHORR THORSTEN , FREYBERGER MATTHIAS
Published: November 2005

We discuss a specific entanglement distillation scheme under the constraint of finite samples of entangled qubit pairs. It is shown that an iterative process can be explicitly formulated. The average fidelity of this process can be enhanced by introducing conditional storing of entangled qubit pairs in each step of the iteration. We investigate the corresponding limitations on the size and the initial fidelity of the sample.
TRPM2 is an ion channel that modulates hematopoietic cell death through activation of caspases and PARP cleavage
Authors: Zhang Wenyi , Hirschler-Laszkiewicz Iwona , Tong Qin , Conrad Kathleen , Sun Shao-Cong , Penn Linda , Barber Dwayne L. , Stahl Richard , Carey David J. , Cheung Joseph Y. , Miller Barbara A.
Published: November 2005

TRPM2 is a Ca2+-permeable channel activated by oxidative stress or TNF-α, and TRPM2 activation confers susceptibility to cell death. The mechanisms were examined here in human monocytic U937-ecoR cells. This cell line expresses full-length TRPM2 (TRPM2-L) and several isoforms including a short splice variant lacking the Ca2+-permeable pore region (TRPM2-S), which functions as a dominant negative. Treatment with H2O2, a model of oxidative stress, or TNF-α results in reduced cell viability. Expression of TRPM2-L and TRPM2-S was modulated by retroviral infection. U937-ecoR cells expressing increased levels of TRPM2-L were treated with H2O2 or TNF-α, and these cells exhibited significantly increased intracellular calcium concentration ([Ca2+]i), decreased viability, and increased apoptosis. A dramatic increase in cleavage of caspases-8, -9, -3, and -7 and poly(ADP-ribose)polymerase (PARP) was observed, demonstrating a downstream mechanism through which cell death is mediated. Bcl-2 levels were unchanged. Inhibition of the [Ca2+]i rise with the intracellular Ca2+ chelator BAPTA blocked caspase/PARP cleavage and cell death induced after activation of TRPM2-L, demonstrating the critical role of [Ca2+]i in mediating these effects. Downregulation of endogenous TRPM2 by RNA interference or increased expression of TRPM2-S inhibited the rise in [Ca2+]i, enhanced cell viability, and reduced numbers of apoptotic cells after exposure to oxidative stress or TNF-α, demonstrating the physiological importance of TRPM2. Our data show that one mechanism through which oxidative stress or TNF-α mediates cell death is activation of TRPM2, resulting in increased [Ca2+]i, followed by caspase activation and PARP cleavage. Inhibition of TRPM2-L function by reduction in TRPM2 levels, interaction with TRPM2-S, or Ca2+ chelation antagonizes this important cell death pathway.
Dominant-negative effects of human P/Q-type Ca2+ channel mutations associated with episodic ataxia type 2
Authors: Jeng Chung-Jiuan , Chen Yu-Ting , Chen Yi-Wen , Tang Chih-Yung
Published: November 2005

Episodic ataxia type 2 (EA2) is an inherited autosomal dominant disorder related to cerebellar dysfunction and is associated with mutations in the pore-forming α1A-subunits of human P/Q-type Ca2+ channels (Cav2.1 channels). The majority of EA2 mutations result in significant loss-of-function phenotypes. Whether EA2 mutants may display dominant-negative effects in human, however, remains controversial. To address this issue, five EA2 mutants in the long isoform of human α1A-subunits were expressed in Xenopus oocytes to explore their potential dominant-negative effects. Upon coexpressing the cRNA of α1A-WT with each α1A-mutant in molar ratios ranging from 1:1 to 1:10, the amplitude of Ba2+ currents through wild-type (WT)-Cav2.1 channels decreased significantly as the relative molar ratio of α1A-mutants increased, suggesting the presence of an α1A-mutant-specific suppression effect. When we coexpressed α1A-WT with proteins not known to interact with Cav2.1 channels, we observed no significant suppression effects. Furthermore, increasing the amount of auxiliary subunits resulted in partial reversal of the suppression effects in nonsense but not missense EA2 mutants. On the other hand, when we repeated the same coinjection experiments of α1A-WT and mutant using a splice variant of α1A-subunit that contained a considerably shorter COOH terminus (i.e., the short isoform), no significant dominant-negative effects were noted until we enhanced the relative molar ratio to 1:10. Altogether, these results indicate that for human WT-Cav2.1 channels comprising the long-α1A-subunit isoform, both missense and nonsense EA2 mutants indeed display prominent dominant-negative effects.
Involvement of calmodulin and myosin light chain kinase in activation of mTRPC5 expressed in HEK cells
Authors: Kim Min Tae , Kim Byung Joo , Lee Jae Hwa , Kwon Seong Chun , Yeon Dong Soo , Yang Dong Ki , So Insuk , Kim Ki Whan
Published: November 2005

The classic type of transient receptor potential channel (TRPC) is a molecular candidate for Ca2+-permeable cation channels in mammalian cells. Because TRPC channels have calmodulin (CaM) binding sites at their COOH termini, we investigated the effect of CaM on mTRPC5. TRPC5 was initially activated by muscarinic stimulation with 50 μM carbachol and then decayed rapidly even in the presence of carbachol. Intracellular CaM (150 μg/ml) increased the amplitude of mTRPC5 current activated by muscarinic stimulation. CaM antagonists (W-7 and calmidazolium) inhibited mTRPC5 currents when they were applied during the activation of mTRPC5. Pretreatment of W-7 and calmidazolium also inhibited the activation of mTRPC5 current. Inhibitors of myosin light chain kinase (MLCK) inhibited the activation of mTRPC5 currents, whereas inhibitors of CaM-dependent protein kinase II did not. Small interfering RNA against cardiac type MLCK also inhibited the activation of mTRPC5 currents. However, inhibitors of CaM or MLCK did not show any effect on GTPγS-induced currents. Application of both Rho kinase inhibitor and MLCK inhibitor inhibited GTPγS-induced currents. We conclude that CaM and MLCK modulates the activation process of mTRPC5.