bluuebunny/crossref_metadata_2025 huggingface dataset:
Rate of defoliation of balsam fir in relation to spruce budworm attack and timing of spray application
Authors: Blais J. Robert
Published: April 2011

Studies were conducted in 1976 and 1977 to determine feeding behaviour and progressive damage to balsam fir (Abiesbalsamea (L.) Mill.) throughout the larval feeding period of the spruce budworm (Choristoneurafumiferana Clem.).Four plots had high populations of approximately 30 larvae and four had very high populations of over 100 larvae per 45-cm branch tip at peak L2. In early spring emerging second-instar larvae mined needles of old foliage; few buds were attacked prior to third instar. Defoliation of current year's growth was between 70 and 80% in plots with high populations and close to 100% in those with very high populations. In the high-population plots the 25% level of foliage destruction occurred close to peak fifth instar and the 50% level just before peak sixth instar. In plots with very high populations 25% defoliation occurred close to peak third instar and 50% defoliation close to peak fourth instar. The relationship between defoliation patterns and best timing of insecticide application is discussed.
A computer simulation model of forest fire suppression with air tankers
Authors: Simard A. J.
Published: April 2011

A computer simulation model which evaluates air tanker productivity and effectiveness is described. Three hundred equations are required to define the model, which consists of five components: administration, the environment, the fire, ground suppression, and air tanker utilization. AIRPRO, a computer program based on the model, tests various combinations of air tanker resources and tactics and selects the one which minimizes suppression cost plus damage caused by fire. The program contains four loops: the fire, the tactic, the event, and fire dynamics (growth and suppression). The environmental, fire, and ground suppression components were validated by comparing model output with historical data. Output of the air tanker component was examined for reasonableness, compared with previous research, and a sensitivity analysis was performed. It is concluded that an assumption of model validity is reasonable. In applying the model in New Brunswick, it was found that medium sized land-based air tankers were the most cost effective, followed by small land-based air tankers. It was also found that a fleet of three or four aircraft would be optimum.
Variation in response to declining photoperiod among families and stands of white spruce in southeastern Ontario
Authors: Pollard D. F. W. , Ying C. C.
Published: April 2011

Newly germinated seedlings of 66 open-pollinated white spruce Piceaglauca (Moench) Voss families from 11 native stands in southeastern Ontario were investigated for responses to declining photoperiod under controlled environments. Amount of height increment (free growth) during a period of declining photoperiod was studied. Variation in duration of free growth was found mostly associated with the family-within-stand component. The stand effect was negligible and decreased as seedlings aged. Lack of stand differentiation suggests that white spruce stands in. southeastern Ontario may have originated from the same base population. High genetic variation at the family level may reflect an adaptive strategy to cope with the extremely variable local climate.
Mechanized strip-thinning in jack pine reproduction
Authors: Alm A. A. , Pflager S. M. , Schantz-Hansen R.
Published: April 2011

Dense jack pine (Pinusbanksiana Lamb.) reproduction resulting from a 1959 wildfire was mechanically thinned with a rotary cutter. Stocking and growth measurements taken immediately after thinning and after 9 years are presented. Results indicated that the nonselective thinning technique was ineffective in providing adequate stocking of desirable trees. A comparison of height and diameter growth on thinned areas with that on unthinned areas showed no satisfactory growth response resulting from the thinning.
Influence of potassium nutrition on susceptibility of silver maple to ozone
Authors: Noland T. L. , Kozlowski T. T.
Published: April 2011

Silver maple (Acersaccharinum L.) seedlings were supplied with half-strength Hoagland solution containing 0, 2, or 117 ppm K for 6.5 weeks. The seedlings were then fumigated with 30 pphm (parts per hundred million) ozone for 6 h on each of 2 successive days. Seedlings grown with 0 or 2 ppm K showed less ozone injury than seedlings given 117 ppm K. Stomatal opening, associated with high K availability, resulted in increased absorption of ozone, and more leaf injury than in K-deficient plants.
Variance in flushing among and within stands of seedling white spruce
Authors: Pollard D. F. W. , Ying C. C.
Published: April 2011

Early, rapid tests are required to ascertain the structure of white spruce Piceaglauca (Moench) Voss populations of southeastern Ontario, where valuable but limited seed sources have been located through field trials. As a significant phenological character associated with growth and hardiness, rate of flushing was monitored under controlled environments in six half-sib families from each of four stands of white spruce located in southeastern Ontario. Whereas no significant variation occurred among stands, highly significant differences occurred among families within stands throughout the flushing period. Results are interpreted as a reflection of coadaption of populations to the timing of environmental hazards. A comparison is made with the minor geographic and pronounced annual variations in occurrence of last spring frost.
Atypical needle fascicles in Pinusconforta
Authors: Pollack John C. , Dancik Bruce P.
Published: April 2011

Specimens of lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) with one to five needles per fascicle were found in Jasper National Park, Alberta. The maximum percentage of atypical fascicles occurred at 2150 m above sea level. These trees bore significantly greater percentages of atypical fascicles than trees at 2000 m and 1850 m above sea level.
A photographic method for measuring tree defect
Authors: Thies Walter G. , Harvey Jr. Robert D.
Published: April 2011

A method is described for measuring volume of defect in trees. The method involves photographing disks cut from the boles of sample trees and then measuring the defect area showing on the photographs with an electronic planimetre.
Modélisation de la coulée de l'érable à sucre (Acersaccharum Marsh.) à partir d'éléments météorologiques
Authors: Plamondon André P. , Bernier Pierre Y.
Published: April 2011

It has already been shown that a relation exists between the daily rate of spring sap flow and the twig temperature of sugar maple. The authors first develop a method to calculate this temperature from radiation, wind speed, and air temperature. For each sap flow cycle, the values of four factors controlling the phenomenon are determined: the number of hours and degree-hours below 0 °C and above 0 °C. Each factor is then converted into an efficiency function. The combination of the four functions gives the global efficiency of the climatic conditions for each sap flow cycle. The flows calculated from the global efficiency are strongly correlated (r = 0.94) with the measured ones.
Variation in red pine (Pinusresinosa) foliar nutrient concentrations as influenced by sampling procedure
Authors: White Edwin H. , Jokela Eric J.
Published: April 2011

Paired foliar samples were collected by shooting with a shotgun versus climbing and clipping near terminal foliage from twentythree 40-year-old Pinusresinosa Ait. trees located on a glacial outwash loamy sand. Samples were analyzed for N, P, K, Ca, and Mg concentrations. Regression analyses indicated that the foliar nutrient concentrations of the "shot" samples, which came from the lower crown, would be poor predictors for the foliar nutrient concentrations of the "cut' samples. Paired t-tests indicated that the shot samples consistently and significantly resulted in lower estimates of foliar concentrations of N, P, and K than did the cut samples. Shot samples were significantly higher in Ca concentrations than cut samples. The results indicate that caution is advised in the use of sampling techniques that do not result in foliar samples being collected from proven diagnostic, standardized near-terminal crown positions.
Epidemiology of Melampsoramedusae leaf rust of poplars in the north central United States
Authors: Widin K. D. , Schipper Jr. A. L.
Published: April 2011

Development of the aecial and uredial stages of Melampsoramedusae leaf rust of poplar in relation to the phenology of its hosts (Populus spp. and Larix spp.) was monitored from March until October during two consecutive growing seasons in central Iowa, east central Minnesota, and north central Wisconsin. Both years, in Wisconsin, larch needles flushed in early May and poplar leaves flushed in mid-May to late May. Aeciospores of M. medusae were found on spore traps only at the Wisconsin site (within the natural range of larch) from May 19 until the end of June in 1975 and 1976. Uredospores were present in the north central United States from mid-June through late September during both years. Temperatures between 15° and 20 °C and periods of precipitation favored uredospore production. Poplar leaf rust was found successively later at more southerly locations.
Nonlinear models fitted to stand volume–age data compare favourably with British Columbia Forest Service hand-drawn volume–age curves
Authors: Nokoe Sagary
Published: April 2011

Nonlinear models developed for sigmoid growth and other relationships were applied to stand volume–age data of interior British Columbia Douglas-fir species group. The five nonlinear models used in the study described the data adequately and compared favourably with corresponding hand-drawn volume–age curves of the British Columbia Forest Service. A major advantage of these fitted models over the hand-drawn curves, however, is that the parameters allow biological interpretation.
Annual cycle of shoot development in sugar maple
Authors: Gregory Robert A.
Published: April 2011

Cytohistology and the development and morphogenesis of sugar maple (Acersaccharum Marsh.) shoots were studied. Three types were recognized: short shoots, long shoots entirely preformed in the bud (Epf long), and long shoots partially preformed in the bud (heterophyllous). The three shoot types varied not only in the size and number of internodes and leaves but also in the development of terminal buds. Terminal bud formation was delayed in heterophyllous shoots but because of a shorter plastochron, which extended later into the growing season, the terminal apices of these shoots were able to annually produce more primordia than in other shoot types. The beginning of embryonic shoot formation, however, began about the same time (late July) for all shoot types.
Litter decomposition and nutrient release in Douglas-fir, red alder, western hemlock, and Pacific silver fir ecosystems in western Washington
Authors: Edmonds Robert L.
Published: April 2011

Decomposition rates and changes in the nutrient content of needle and leaf litter were examined in Douglas-fir (Pseudotsugamenziesii Mirb. Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), Pacific silver fir (Abiesamabilis (Dougl.) Forbes), and red alder (Alnusrubra Bong.) ecosystems in western Washington, U.S.A. Nylon litterbags (1-mm mesh) were placed in the stands in November and December 1974. Bags were collected after 3, 6, 12, and 24 months and weighed, except in the Pacific silver fir stand when bags were collected after 6, 9, 14, and 24 months. Litter was analyzed for C, N, P, K, Ca, Mg, Mn, lignin, and cellulose. Decomposition constants (k values) were determined. Fastest decomposition after 2 years occurred in red alder leaves, followed by Douglas-fir, western hemlock, and Pacific silver fir needles. There were significant differences in weight loss among species after 1 year, but no significant differences were evident after 2 years. Red alder leaves showed rapid weight loss in the 1st year but decomposed little in the 2nd year. Decomposition constants were highly positively correlated with minimum air temperatures and negatively correlated with C:N ratios. Low litter moisture tended to reduce decomposition in summer, particularly in the Pacific silver fir stand. Decomposition proceeded under snow in this ecosystem. The pattern of loss of elements from litterbags after 2 years varied from ecosystem to ecosystem, particularly for N. The following element mobility series resulted for the four ecosystems: red alder (K > Mg > Ca > P > N > Mn), Douglas-fir (K > P > Ca > Mg > Mn > N), western hemlock (K > Ca > Mg > N > Mn > P), and Pacific silver fir (K > Mg > Ca > Mn > P > N).
Leaf gas exchange processes and related characteristics of seven poplar clones under laboratory conditions
Authors: Ceulemans R. , Impens I.
Published: April 2011

Different ecophysiological characteristics of various Populus clones (maximum net CO2 uptake rate, apparent quantum yield, photon flux density compensation point, boundary layer resistance, and stomatal and internal resistances to carbon dioxide and water use efficiency) were studied using a gas exchange method. Most significant differences were found in the water use efficiency ratios, the internal resistances to carbon dioxide and the maximum net CO2 uptake rates. Recently selected interamerican Populustrichocarpa crossings (Populus clones Unal, Beaupré, and Trichobel) showed high water use efficiency, high maximum net CO2 uptake rates, and low internal resistances.
Activity of Hylastesnigrinus, a vector of Verticicladiellawageneri, in thinned stands of Douglas-fir
Authors: Harrington T. C. , Cobb Jr. F. W. , Lownsbery J. W.
Published: April 2011

Live adults of Hylastesnigrinus (Mann.), a root-feeding bark beetle suspected of being a vector of Verticicladiellawageneri Kendr., were trapped in infection centers of black stain root disease and allowed to feed on seedlings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in the greenhouse. Three of 22 beetles that were artificially contaminated with conidia of V. wageneri introduced the pathogen into seedlings. One of 47 seedlings infested with pairs of H. nigrinus that were not artificially contaminated became infected with V. wageneri. The activity of H. nigrinus in thinned plots at three sites near the North Coast of California was monitored with sticky traps. In 1981, 100 adults were trapped in plots mechanically thinned on 13 April 1981. Only two H. nigrinus were trapped in unthinned, control plots. Twenty-two adults were trapped in plots chemically thinned by the injection of cacodylic acid. In 1982, as many or more adults were trapped in plots that were thinned after the seasonal peak of H. nigrinus in 1981 as in plots that were freshly thinned. Roots of living Douglas-fir trees examined in a mechanically thinned plot had feeding wounds similar to those described as feeding wounds made by H. nigrinus. Roots of living Douglas-fir in an unthinned plot had no evidence of insect feeding. Although no black stain was found associated with feeding wounds on living trees, the previously noted association of black stain root disease in thinned stands may still be due to an increased activity of H. nigrinus.
Site and fertilizer effects on northern hardwood stump sprouting
Authors: Mroz G. D. , Frederick D. J. , Jurgensen M. F.
Published: April 2011

Early growth of northern hardwood stump sprouts was studied to determine the short rotation biomass production of coppiced, pole-sized stands. This included studying the effects of fertilizer amendments and site quality on sprout numbers and height as well as biomass. Sprout numbers were related to stump diameter and species, but were independent of site quality and fertilizer additions. Sprout height growth on a stump was independent of numbers and showed increases with site quality. Biomass per stump and per hectare showed increases with N–P–K fertilization on the medium and high sites because of increased available water capacity. Mean annual increments after 4 years ranged from 0.1 Mg ha−1 year−1 on the low site to 1.6 Mg ha−1 year−1 with N–P–K fertilization on the high site. Comparisons of 3- and 4-year-old sprout growth showed large 4th-year biomass increases with periodic annual increments ranging up to 4.8 Mg ha−1 year−1 on the high site N–P–K treatments. Biomass responses to fertilization were for the large part nonsignificant owing to wide variability of biomass on blocks within sites. This may be due to inherent soil factors or large N and K losses following whole-tree harvesting of the original stands.
Tree life history strategies: the role of defenses
Authors: Loehle Craig
Published: April 2011

Analysis of energy partitioning between defensive investments and growth in woody plants indicates that increasing a tree's life-span should require increased energy investment in protective measures such as thick bark and defensive chemicals. Increased investment in such defenses, however, logically must slow down the growth rate, thereby raising the mortality rate for juveniles in competition for height growth. Early reproduction should also reduce the growth rate. It is hypothesized that rapid growth can substitute for these defenses, but the consequence is rapid decline upon reaching maturity. These predictions are tested with data compiled from the literature for 159 species of North American trees. Data analysis supports predictions. Longevity of angiosperms, but not of gymnosperms was correlated with increased investment in defenses as measured by volumetric heat content of the wood. Wood density was not as good a measure. Longevity of gymnosperms was predicted by resistance to wood decay. For both taxa there was a negative correlation between growth rate and longevity, supporting the hypothesis of growth trade-offs. Age of sexual maturity was closely predicted by longevity in angiosperms. There was no such relationship for conifers as a whole, though there was for pines. The lack of relationship for all conifers might be explained by (i) variation in reproductive opportunities for young trees of different species, or (ii) variation in growth rates of young trees in certain adverse habitats occupied by conifers.
Climatic comparisons with tree-ring data from montane forests: are the climatic data appropriate?
Authors: Kimball Kenneth D. , Keifer MaryBeth
Published: April 2011

The appropriateness of relating spatially proximate (40-km radius) temperature and precipitation data from different elevations to montane forest growth patterns was investigated for Mount Washington, New Hampshire. Monthly mean temperature and total precipitation data (1933–1983) were correlated (p < 0.05) among all pairs of meteorological stations (280, 420, 610, 1915 m and regional averages) on or near Mount Washington. The unexplained variance (1 − r2) for precipitation comparisons between meteorological stations was greater relative to temperature. When correlated with the average tree-ring index chronology of 90 red spruce trees on Mount Washington (800–1200 m), the monthly temperature data yielded similar correlative patterns among the four meteorological stations. However, the monthly temperature data from the meteorological stations (610 and 1915 m) most proximate to the montane forest study site were correlated (p < 0.10) with the tree-ring indices for two to three times as many months as the temperature data from the lower elevations. There was no consistency in correlative results of tree-ring indices with monthly precipitation data among the four meteorological stations. However, precipitation measurements and Palmer drought indices are poor indicators of moisture availability in montane forests. We conclude that spatially proximate, low elevation temperature data can underestimate correlative relationships between temperature and montane tree-ring data in the northeastern United States.
Biomass, net primary production, and nutrient distribution for an age sequence of Populustremuloides ecosystems
Authors: Ruark G. A. , Bockheim J. G.
Published: April 2011

The amounts and proportions of dry matter and macronutrients were measured in overstory trembling aspen (by tissue), understory vegetation, woody detritus, the forest floor, and the mineral soil in duplicate stands of 8, 14, 18, and 32 years and in a single stand of 63 years on an Entic Haplorthod in northern Wisconsin. The following changes occurred during secondary succession: (i) above- and below-ground aspen biomass increased, (ii) aboveground aspen production peaked between the ages of 18 and 32 years, (iii) the root to shoot ratio (R/S) of overstory aspen declined, (iv) the amounts and ecosystem proportions of macronutrients (N, P, K, Ca, and Mg) in the aspen overstory increased, and (v) the ecosystem proportions of nutrients in the understory declined. As the relative abundance of nutrients in overstory aspen increased, the labile nutrient pool in the mineral soil, particularly Mg and Ca, declined. The study suggests that understory roots play an important role in nutrient retention of successionary aspen stands in the upper Great Lakes region. Understory vegetation had an average R/S of 4.5 (compared with 0.18 to 0.58 for overstory aspen), with their small-root (< 0.3 cm) biomass comprising about 76% of the total ecosystem small-root pool. The proportion of nutrients in the living vegetation accounted for by the understory declined with stand age. However, from 13 to 24% of the total plant-available ecosystem amounts of nutrients resided in the understory of the 63-year-old stand. Relative to the ecosystem development model of Bormann and Likens, the reorganization phase in successionary aspen stands of the upper Great Lakes region may last 5 years or less. The aggradation phase lasts until about 70 years, after which time aspen is replaced by northern hardwoods.
Establishment of western white pine shoots invitro using needle fascicles
Authors: Stiff C. M. , Wenny D. L. , Dumroese R. K. , Roberts L. W. , Stiff C. T.
Published: April 2011

The foliage of 4-year-old western white pine (Pinusmonticola Dougl.) containerized seedlings was treated with 450 ppm benzylaminopurine weekly, for 8 weeks, to induce the development of fascicle buds. Fascicle buds were cultured invitro on five different media. Gresshoff and Doy 1 medium and Gresshoff and Doy 1 with an increased concentration of potassium nitrate (1500 mg L−1 KNO3 was added) yielded greater bud elongation and secondary needle growth than other media tested. An invitro dip in 2000 ppm naphthaleneacetic acid promoted the formation of white glassy callus, potential root primordia, and root growth in 33% of the explants. Only 10% of the explants developed elongated roots 120 days after initial culture.
Isozyme assessment of the genetic stability of micropropagated hybrid larch (Larix × eurolepis Henry)
Authors: Richard Sylvie , Gauthier Sylvie , Laliberté Sylvie
Published: April 2011

The search for the occurrence of somaclonal variation of in vitro shoots and acclimatized plants of a hybrid larch (Larix × urolepis Henry) clone was performed by the analysis of eight isozyme systems. Cultures were established from short shoot buds of mature material. The effects of growth regulators in the media, subculture intervals, and periods in culture were analyzed for in vitro shoots. Variability was found in in vitro shoots but appeared to be related to a physiological response to culture conditions. Once acclimatized, most tissuecultured plants expressed the same enzymatic patterns as those of control plants (stecklings and the ortet). The variations observed for some acclimatized plants were also observed in control plants and were not related to ontogenic stage. Results from the isoenzymatic systems studied showed that hybrid larch plants regenerated from tissue culture were not significantly different from stecklings and the ortet.
The role of micro-arthropods in the defacement of sawn lumberby sapstain and mould fungi
Authors: Powell M.A. , Eaton R.A. , Webber J.F.
Published: April 2011

Fungal sap stain, mould, and basidiomycete defacement of boards sawn from the sapwood of freshly felled logs of Corsican pine (Pinusnigra var. maritima (Aiton) Melville) was assessed during a 14-week field trial at a sawmill in southern England. The boards were placed in nonstickered stacks to reduce moisture loss, and stacks were constructed in a nest arrangement to allow experimental untreated board samples to be positioned centrally in each stack. The experimental samples were placed in plastic tanks, and the open tank faces were left either uncovered or were covered with a fine-mesh nylon screen to prevent entry of micro-arthropods. All the experimental samples were sterilized by γ-radiation prior to the tanks being installed into the board stacks. The outer casing boards, which surrounded the experimental tanks in each stack, were dip treated with a fungicide, a broad-spectrum insecticide-acaricide, a combination of the fungicide and the insecticide-acaricide, or water, which served as a control. After 8 and 14 weeks of exposure, casing boards were inspected for fungal infestation. The experimental sample boards removed from the centre of the stacks at the 8-week inspection were also assessed for fungal infestation. Boards that were accessible to arthropods (i.e., in open tanks surrounded by non-insecticide-treated boards) suffered severe sap stain. Experimental boards protected from arthropods by a mesh screen and (or) casing timbers treated with the insecticide chemical had minimal sap stain. In contrast, colonization by moulds was not reduced when either physical or chemical barriers were in place, suggesting that mould spores were mainly transmitted by air currents. Micro-arthropods were clearly implicated as primary agents of sap-stain transmission on green sawn lumber. They may also graze the moulds and therefore limit the intensity of defacement by these fungi.
Ten-year growth comparison between rooted cuttings and seedlings of loblolly pine
Authors: Stelzer H E , Foster G S , Shaw V , McRae J B
Published: April 2011

Rooted cuttings and seedlings of loblolly pine (Pinus taeda L.) were established in a central Alabama field trial. Five, full-sib families, with an average number of six clones per family, were evaluated. Mean cutting/seedling height ratios revealed that despite initial differences in size, relative growth rates of both propagule types stabilized and were equal by age 7 years. Through age 10 years, results show virtually no difference in height, diameter at breast height, volume, or stem taper between the rooted cuttings and seedlings.
A review of conceptual landscape planning models for multiobjective forestry in Sweden
Authors: Fries Clas , Carlsson Mattias , Dahlin Bo , Lämås Tomas , Sallnäs Ola
Published: April 2011

This paper reviews the approaches to multiple objective landscape planning that have developed in Swedish forestry in the 1990s. The objectives of such planning include primarily timber production and maintenance of biodiversity, but also aspects such as aesthetics and recreation. The variety of approaches and models that have emerged is caused by regional differences in land-use history, forest conditions, recreation pressure, and ownership. We distinguish three approaches: The species approach and the naturalness approach integrate conservation aspects, while the multiple aspects approach integrates several aspects (biological, social, economic, spiritual, etc.) into commercial timber-producing forestry. The species approach is exemplified by the key habitat - corridor model in which key habitats and corridors are preserved to support certain species. The natural landscape model illustrates an example of the naturalness approach, as it integrates natural forest features from a fire-disturbed landscape and gives examples of management implications at the landscape as well as at the stand level. The multiple aspects approach combines several objectives and defines important structures rather loosely. This approach was developed in areas where private nonindustrial forestry dominates. Nontimber and nonconservation aspects therefore become relevant to forest management. The supportive feature model exemplifies an application of that approach.
Influence of forest age on forms of carbon in Douglas-fir soils in the Oregon Coast Range
Authors: Entry James A , Emmingham William H
Published: April 2011

The amount and type of carbon (C) in a forest soil reflects the past balance between C accumulation and loss. In an old-growth forest soil, C is thought to be in dynamic equilibrium between accumulations and losses. Disturbance upsets this equilibrium by altering the microclimate, the amount and type of vegetation growing on a site, and properties that affect organic matter decomposition. We measured total C and forms of soil C in the L, F, and H layers and in the light fraction of soil organic matter in the 0-10 cm of mineral soil in old-, second-, and young-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) soils in the Oregon Coast Range. Total C in L, F, and H layers and in organic material in the top 10 cm of mineral soil in old-growth forests was higher than in young- or second-growth forests. Old-growth forests had a higher lignin concentration and lower concentrations of sugar, hemicellulose, and cellulose in the L, F, and H layers and in the light fraction of organic material than second- or young-growth forests. Old-growth forests had greater amounts of fats, waxes, and oils, sugar, cellulose, and lignin, in the L, F, and H layers per square hectare and greater amounts of hemicellulose, cellulose, and lignin in the light fraction of organic matter in the 0-10 cm of mineral soil per square hectare than young- and second-growth forests. Concentrations of fats, waxes, and oils, sugar, and tannin in the light fraction of organic matter in the 0-10 cm of mineral soil did not differ with forest age.
Sequential sampling of normal and non-normal populations
Authors: Robinson Andrew P , Burk Thomas E
Published: April 2011

This paper reports a simulation-based exploration into the computation of point and interval estimates for data arising from sequential sampling of populations with a variety of underlying distributions. We conclude that the coverage probability of the standard frequentist confidence interval estimates is overstated. The effect of non-normal behavior in the underlying population upon the properties of the interval estimate varies, depending upon the severity and type of anomaly (skewness, kurtosis, etc). Sequential sampling of certain nonsymmetric distributions performed very poorly compared with simple random sampling. We assess other interval estimates that do not overstate the coverage probability if the underlying population is normal (Gaussian).
Species variability in growth response to light across climatic regions in northwestern British Columbia
Authors: Wright Elaine F , Coates K Dave , Canham Charles D , Bartemucci Paula
Published: April 2011

We characterize variation in radial and height growth of saplings of 11 tree species across a range of light levels in boreal, sub-boreal, subalpine, and temperate forests of northwestern British Columbia. Shade-tolerant species had the greatest response to an increase in light at low-light levels but had low asymptotic growth at high light. Shade-intolerant species had weaker responses to increases at low light but had the highest growth rates at high light. The effects of climate on intraspecific variation in sapling response to light were also related to shade tolerance: across different climatic regions, the most shade-tolerant species varied in their response to low-light but not high light, while shade-intolerant species varied only in their high-light growth. Species with intermediate shade tolerance varied both their amplitude of growth at high light and the slope of the growth response at low light. Despite the interspecific trade-offs between high- and low-light growth, there was a striking degree of overlap in the light response curves for the component species in virtually all of the climatic regions. Successional dynamics in these forests appear to be more strongly governed by interspecific variation in sapling survival than growth.
Analyse de la réponse de la végétation aux trouées naturelles dans une futaie âgée de Quercus ilexL. en Corse (île Méditerranéenne)
Authors: Panaïotis Christophe , Loisel Roger , Roux Maurice
Published: April 2011

Green oak (Quercus ilexL.) is the most common forest species growing under Mediterranean climate. Because of important past anthropic perturbations, green oak old-growth forests are very unfrequent and constitute, for that reason, a most interesting domain where to analyze the natural evolution of green oak stands. Such forests exist in Corsica and this study deals with vegetation successions as they occur in naturally occuring gaps. Because of the taxonomic poorness (32 species), two statistical tools (canonical correspondence analysis and random permutations) were used to take into account vegetation spatial structure according to types (herbaceous, shrubby, or arborescent). These statistical analyses show that plant succession does not really exist in gaps of green oak old-growth forests but rather a structural organization of common species found in the maquis. Results support the hypothesis about the internal dynamics of these forests going through a maquis phase.
Adjustment of estimated tree growth rates in northern California conifers for changes in precipitation levels
Authors: Wensel Lee C , Turnblom Eric C
Published: April 2011

Even with similar initial conditions, observed forest growth rates on permanent sample plots in the conifer region of northern California differ for different periods. Thus, individual-tree growth models built with growth parameters estimated from data from one period may not produce accurate estimates for another period unless some allowance is made for this variation in growth rates. Variation in growth rates of northern California conifers through time has been shown to be correlated with precipitation changes. A method is presented that adjusts periodic growth estimates for variation in precipitation between periods. This provides a basis for adjusting short-term growth data for making long-term growth projections. Perhaps more importantly, short-term inventory updates might be made more accurately.
Influence of thinning and burning restoration treatments on presettlement ponderosa pines at the Gus Pearson Natural Area
Authors: Feeney Shelly R , Kolb Thomas E , Covington W Wallace , Wagner Michael R
Published: April 2011

This study assessed the effects of restoration treatments on growth, leaf physiology, and insect resistance characteristics of presettlement-age ponderosa pines (Pinus ponderosa Dougl. ex Laws.) at the Gus Pearson Natural Area in northern Arizona. Treatments (C, control; T, thinned from below; TB, thinned and prescribed burned) were designed to restore stand structure and disturbance regime to a pre-Euro-American settlement reference condition. Tree growth and some physiological characteristics differed between wet (1995) and dry (1996) years. Soil water content was greater in both thinned treatments than in the control. Compared with the control, trees in both thinned treatments had greater leaf nitrogen content (C = 1.44, T = 1.57, TB = 1.59 g·m-2), leaf toughness (C = 65.1, T = 71.3, TB = 69.3 g), and basal area increment (C = 14.3, T = 19.9, TB = 20.7 cm2). Resin flow was greater in the thinned and burned treatment (12.2 mL·day-1) than in the thinned treatment (4.3 mL·day-1) and control (3.6 mL·day-1). Treatment differences in predawn water potential and net photosynthetic rate varied among sample dates, with the largest differences during a period of drought (C < T and TB). Our results suggest that restoration treatments improved resource uptake, growth, and insect resistance capabilities of presettlement ponderosa pines.
Riparian forest strips as habitat for snowshoe hare in a boreal balsam fir forest
Authors: Darveau Marcel , Huot Jean , Bélanger Louis
Published: April 2011

Riparian forest strips are usually protected from logging for their buffer effect on aquatic habitats. However, their value to terrestrial wildlife species such as snowshoe hare (Lepus americanus Erxleben) is unknown. From 1990 to 1996, we compared habitat characteristics (shrubs and saplings 0.25-2.25 m high), hare browsing, and hare pellet densities in five types of experimental riparian forest strips (20, 40, 60, and >300 m wide intact strips, and 20 m wide thinned strips), in a humid boreal balsam fir (Abies balsamea (L.) Mill.) landscape managed primarily for timber harvesting in Quebec. Based on coniferous and deciduous shrub densities, all riparian forest strips and adjacent clearcuts remained low-quality habitats for hare over 6 years following clear-cutting. Only 103 shrubs were browsed in a 1500-m2 area sampled over 3 years, of which only 33 had >20% of browsed stems. Nevertheless, pellet data revealed a low but sustained use of all strips each summer and winter, and there were no changes over 6 years (mean 280 pellets/ha per month; P > 0.05). Whether hare populations are cyclic or not in our region remains an open question. However, they show some fluctuations and timber harvesting coincided with "high" hare populations in our study area. Sampling in "low" years might show that fewer hares occupy the forest strips. Further work is required to determine the influence of regional and local perturbations on the use of riparian forest strips by snowshoe hares.
Woody residue management to reduce nitrogen and phosphorus leaching from sandy soil after clear-felling Pinus radiata plantations
Authors: Carlyle J Clive , Bligh Mark W , Nambiar EK Sadanandan
Published: April 2011

We studied the potential of woody residue management to reduce N and P leaching from sandy soils after clear-felling Pinus radiata D. Don. stands in southeastern Australia. Treatment variables were (i)branch diameter, (ii)branch mass, (iii)branch placement (surface or buried), and (iv)branch comminution. Treatments were applied to zero-tension lysimeters containing homogenized soil, forest floor, and green needles. Leachates from these treatments were collected weekly for 2 years and analysed for mineral N (Nm), soluble organic N, and total soluble P. Addition of 60 Mg·ha-1 of branch residue to the soil surface reduced Nm leaching by 13%, but the same quantity of buried branch reduced Nm leaching by 27%. Comminuting branches before burying further reduced Nm leaching. Much of the effect of placement, mass, and comminution on Nm leaching was related to differences in the surface area of branch material in contact with soil. Comminuting and burying branches reduced P leaching by 31%. An increase in branch N content after 2 years was linearly related to the reduction in Nm leached but accounted for only 23-48% of this reduction. Irrespective of treatment, there were linear relationships between the N and P concentrations in remaining material and the relative mass loss of wood and bark.
Short-term effects of logging on snowshoe hares in the boreal forest
Authors: Ferron Jean , Potvin François , Dussault Christian
Published: April 2011

We investigated snowshoe hare (Lepus americanus Erxleben) abundance, home range size, daily movements, survival, and habitat utilization in black spruce (Picea mariana (Mill.) BSP) stands before and after clearcuts with protection of regeneration (CPR) in southwestern Quebec. Hare abundance was indexed by pellet counts in permanent plots 2 years before and over 4 years following logging (1991-1996). Home range size, daily movements, survival, and habitat use were measured by radiotracking 16 hares before and after logging, during 3 months between May and August 1992; some additional fixes were recorded monthly until the end of March 1993 for additional data on survival. Hare reaction to logging included immediate increased daily movements, larger home ranges involving partial or complete relocation, but no change in survival rate. After logging, hares moved to habitat structurally similar to the one they used before logging, but these sites contained larger trees and a greater proportion of deciduous species. Recent cutovers were unsuitable habitats for snowshoe hares despite protection of regeneration. Hares were still rare in clearcuts 4 years after logging. Residual forests are thus necessary to maintain hare populations in commercial timber landscapes.
Crown efficiency in a loblolly pine (Pinus taeda) spacing experiment
Authors: Sterba Hubert , Amateis Ralph L
Published: April 2011

Crown efficiency was first defined by Assmann (1961. Waldertragskunde. BLV, München) as individual tree volume increment per unit of crown projection area. He hypothesized that within a given crown class, smaller crowns are more efficient because their ratio between crown surface and horizontal crown projection is higher. Data from a loblolly pine (Pinus taeda L.) spacing experiment were used to test if this hypothesis also holds in young loblolly pine stands and, if so, to determine if it explains the increment differences between spacings in the spacing experiment. Using individual tree height relative to plot dominant height to describe crown class, within-plot regression showed that crown efficiency decreased with crown size for trees below dominant height. This relationship was much less pronounced than indicated from Assmann's examples, although the crown surface to crown projection ratio behaved in the same way as Assmann had hypothesized. Crown efficiency as well as the crown surface to crown projection area ratio decreased with increasing density. Basal area increment per hectare increased until total crown closure approached 130% and then stayed constant. This major impact of total crown coverage brings into question the usefullness of crown efficiency as an indicator for unit area growth.
Aboveground biomass and nitrogen allocation of ten deciduous southern Appalachian tree species
Authors: Martin Jonathan G , Kloeppel Brian D , Schaefer Tara L , Kimbler Darrin L , McNulty Steven G
Published: April 2011

Allometric equations were developed for mature trees of 10 deciduous species (Acer rubrum L., Betula lenta L., Carya spp., Cornus florida L., Liriodendron tulipifera L., Oxydendrum arboreum (L.) DC., Quercus alba L., Quercus coccinea Muenchh., Quercus prinus L., and Quercus rubra L.) at the Coweeta Hydrologic Laboratory in western North Carolina, U.S.A. These equations included the following dependent variables: stem wood mass, stem bark mass, branch mass, total wood mass, foliage mass, total biomass, foliage area, stem surface area, sapwood volume, and total tree volume. High correlation coefficients (R2) were observed for all variables versus stem diameter, with the highest being for total tree biomass, which ranged from 0.981 for Oxydendrum arboreum to 0.999 for Quercus coccinea. Foliage area had the lowest R2 values, ranging from 0.555 for Quercus alba to 0.962 for Betula lenta. When all species were combined, correlation coefficients ranged from 0.822 for foliage area to 0.986 for total wood mass, total tree biomass, and total tree volume. Species with ring versus diffuse/semiring porous wood anatomy exhibited higher leaf area with a given cross-sectional sapwood area as well as lower total sapwood volume. Liriodendron tulipifera contained one of the highest foliar nitrogen concentrations and had consistently low branch, bark, sapwood, and heartwood nitrogen contents. For a tree diameter of 50 cm, Carya spp. exhibited the highest total nitrogen content whereas Liriodendron tulipifera exhibited the lowest.
Genetic gain with desired status number in breeding programs: a study on selection effects
Authors: Wei R -P , Hansen C R , Dhir N K , Yeh F C
Published: April 2011

Genetic gain and average coancestry or status number was investigated for five selection methods: penalty index selection (PIS), family index selection (FIS), combined between-family and within-family selection (CBW), restricted individual selection (RIS), and combined index selection (RCS). PIS was a function of an individual's breeding value and family contributions, modelled as a stepwise procedure to select superior individuals one by one. A penalty would indicate the need to have low average coancestry or large status number. Breeding populations of unrelated families were investigated by Monte Carlo simulation to examine the genetic response of the five selection methods at a restricted selection intensity and average coancestry. PIS attained the greatest genetic gain, except at the selection limits of maximum genetic gain and minimum average coancestry where PIS might be identical to the other selection methods. FIS and RCS well approximated PIS at high average coancestry. RIS was similar to RCS when the heritability was high, particularly at low average coancestry. CBW attained the least genetic gain among the selection methods. For all selections, high heritability would contribute to a greater genetic gain and status number or low average coancestry. PIS was applied to a practical breeding program in Alberta that included several subpopulations. The results suggested that the selection efficiency for balancing genetic gain and average coancestry would increase when deploying a subpopulation strategy for breeding population management.
The forest stand margin area in the interpretation of growing stock using Landsat TM imagery
Authors: Tokola Timo , Kilpeläinen Pertti
Published: April 2011

In this study the reliability of the interpretation of growing stock volume from a satellite image in a forest stand margin area was investigated. The accuracy of the estimation result was lower close to the stand edge (R2 = 0.118) than inside the stands (R2 = 0.510). Neighbouring areas affect the pixel reflectance values. When the field data of edge sample plots were derived from the closest neighbouring stand, the volume estimate error was the smallest. Three different edge-detection methods were tested. The Canny operator performed better than Haralick's correlation or local adaptive binarization. It was able to produce edge differences between non-edge plots and plots where a sharp edge is closer than 50 m from the plot. If a slight edge is closer than 30 m from the plot, edge operators still produced a similar response to non-edge plots. The accuracy of edge detection algorithms was not sufficient to improve the final interpretation result. On the other hand, if all sample plots in the forest margin area were ignored in the training data, the results were biased. Thus, a field data set for forest inventory based on satellite image interpretation should also include forest margin plots.
Estimation of basic density of Eucalyptus globulus using near-infrared spectroscopy
Authors: Schimleck Laurence R , Michell Anthony J , Raymond Carolyn A , Muneri Allie
Published: April 2011

Basic density and pulp yield are two very important factors in determining the economics of chemical pulping. A method for estimating pulp yields has been developed by measuring the near-infrared spectra of wood powders from cores withdrawn from standing eucalypt plantation trees using motorized equipment. This paper examines the precision with which the basic density of the woods might be predicted from the same near-infrared spectra. We found that the basic densities of woods from plantation-grown 8-year-old Eucalyptus globulus Labill. subsp. globulus (Tasmanian blue gum) ranging from 378 to 656 kg/m3 could be determined with an accuracy of prediction of ca. ±30 kg/m3. This error compares with the accuracy of prediction of pilodyn density measurements on similar samples of ca. ±22 kg/m3. The basic densities of increment cores having relatively low basic densities were consistently overestimated and those having relatively high basic densities were consistently underestimated by the near-infrared spectroscopic method.