bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanism of nitrate loss from a forested catchment following a small-scale, natural disturbance
Authors: Hobara Satoru , Tokuchi Naoko , Ohte Nobuhito , Koba Keisuke , Katsuyama Masanori , Kim Su-Jin , Nakanishi Asami
Published: April 2011

In Matsu-zawa catchment, central Japan, nitrate concentrations in stream water increased following a small-scale, natural disturbance involving an outbreak of pine wilt disease that affected ~25% of the forested catchment. To clarify nutrient dynamics in soils and their relationship with stream water nitrate, we investigated soil nitrogen dynamics and soil water chemistry in disturbed and undisturbed, water-unsaturated and -saturated plots. The highest values for nitrification rate, nitrate concentration in soil solution, and nitrate exported from the root zone were observed for the disturbed plot. The ratio of nitrification to mineralization in surface soil of the disturbed plot dramatically increased from 1989 (pre-disturbance) to 1997. Root zone leachate from the disturbed area showed gradually increasing groundwater nitrate concentrations in the temporarily saturated zone during lateral, matrix flow. The catchment's deep soils and associated hydrologic processes limited the degree of plant uptake of the nitrate generated in the disturbed area. It was inferred that the persistent high levels of nitrate observed in the stream water resulted largely from the stable high nitrate concentrations observed in the saturated groundwater of this catchment. Stream water nitrate loads discharged following the disturbance were about 16 times greater than prior to it.
Thinning of mature lodgepole pine stands increases scolytid bark beetle abundance and diversity
Authors: Hindmarch Trevor D , Reid Mary L
Published: April 2011

Thinning of forests has been used as a management tool for bark beetles; however, its effects have only been studied in a limited number of bark beetle species, and the causes of its effectiveness remain unclear. We sampled the abundance and diversity of secondary bark beetles in mature thinned and unthinned lodgepole pine, Pinus contorta Dougl. ex Loud., stands (ca. 840 and 2500 trees/ha, respectively) near Whitecourt, Alberta. We examined the factors that might influence any differences in abundance and diversity between thinned and unthinned stands. Breeding habitat for secondary bark beetles (fresh coarse woody debris) was much more abundant in thinned stands than in unthinned stands in the first year after thinning but then returned to background levels. Temperature and wind speeds were higher in thinned stands in all 3 years after thinning. The abundance of striped ambrosia beetles, Trypodendron lineatum Olivier, and pine engravers, Ips pini (Say), captured in baited funnel traps and window traps remained significantly higher in thinned stands than in unthinned stands in all 3 years after thinning, while the diversity of bark beetles remained constant or increased over this period. Our data suggest that the persistent changes in microclimate following thinning, especially increased wind, were partly responsible for thinned stands having more secondary bark beetles than unthinned stands.
Red-listed and indicator lichens in woodland key habitats and production forests in Sweden
Authors: Johansson Per , Gustafsson Lena
Published: April 2011

There are ca. 70 000 "woodland key habitats" (WKHs) in Sweden that according to definition should contain red-listed species, but their species content is seldom known. Indicator species are used as one tool to identify the WKHs. In two areas in southern Sweden red-listed and indicator lichen species were surveyed in line transects in a total of 25 WKHs (45 ha) and, for comparison, in 74 ha of surrounding production forest. Altogether 19 red-listed species, representing ca. 25% of the Swedish Red List forest lichen species so far recorded from the study areas, and 35 indicator species were found. Ninety-five percent of all records were epiphytic. The most evident result from this study was the large difference in the number of species records in the production forests between the two study areas. In contrast, the WKHs in both areas had a similar number of species records. The WKHs were expected to be significantly richer than the production forests in regard to the occurrence of indicator and red-listed species, but this was only found to be true in one of the areas. In both areas there was a tendency for the rarest red-listed species to be confined to the WKHs. Nestedness and correlation analyses suggested that Arthonia vinosa was a relevant indicator of red-listed lichens; however, Calicium parvum was found to be inappropriate as an indicator species. It is concluded that at the regional scale the production forest can host considerable amounts of indicator and red-listed lichen species but that the WKHs are important for the preservation of rare lichens.
Spatial distribution of injuries to Norway spruce advance growth after selection harvesting
Authors: Granhus Aksel , Fjeld Dag
Published: April 2011

Injuries and mortality to advance growth (saplings) after selection harvesting was studied in 17 multistoried Norway spruce (Picea abies (L.) Karst.) stands. Harvest removals ranged from 33 to 67% of initial basal area. Four of the stands were harvested with a motor-manual method (chain saw and skidding with farm tractors; MFT). The remaining stands were harvested with single-grip harvesters and forwarders (HFW). In each stand, injury rates were evaluated on a 24 × 48 m plot, located between the centre lines of two parallel strip roads that were spaced 24 m apart. All logging teams had at least 5 years of experience in clear-cutting and thinning operations. The trees to be removed and the strip road centre lines were marked prior to harvest. Mortality varied from 5 to 51%, whereas total injury (injured + dead saplings) varied from 17 to 76%. Mortality and injury levels were generally highest on HFW plots. Crown reduction and leaning stems were the most frequent types of injury, regardless of operating method. Injury rates increased with sapling height with the HFW method, whereas the opposite was found on MFT plots. Saplings without preharvest damage in the form of top or leader defects had a higher probability of being injured than saplings with such damage in stands harvested with the MFT method. A similar difference was not found on HFW plots. A logistic regression model shows that the spatial risk of injury depends on the interaction between forest condition factors and operational characteristics. Forest condition factors influencing the risk of injury are sapling height and the location of saplings relative to larger residual trees and strip roads. Corresponding operational characteristics are operating method and harvest intensity.
Prediction of stand susceptibility and gypsy moth defoliation in Coastal Plain mixed pinehardwoods
Authors: Davidson C B , Johnson J E , Gottschalk K W , Amateis R L
Published: April 2011

The European gypsy moth (Lymantria dispar L.) is an introduced defoliator that has become endemic in forests of the northeastern United States. During the last five decades, populations have continued to advance into the southeastern United States. Defoliation outbreaks continue to occur along the leading edge of the infestation, and the potential for extensive defoliation within southern forests remains. A field study was implemented in 1991 to determine the relationship between species composition and gypsy moth defoliation in Coastal Plain mixed pinehardwood stands and to formulate a defoliation prediction model. Stands in both pineoak and pinesweetgum cover types were extensively defoliated during a single defoliation outbreak. Mean stand defoliation in the pineoak type peaked at 42.6% in 1994, while mean defoliation in the pinesweetgum type peaked at 32.8% in 1995. Defoliation intensity was significantly related to stand composition, with oaks and sweetgum being defoliated at the greatest intensities. Overall, pines were not heavily defoliated in either cover type. However, moderate to heavy defoliation of a small number of overstory pines was observed in some pineoak stands and appeared to be due to a threshold level of oak defoliation (>80%). A nonlinear model for the prediction of mean total stand defoliation is also presented. Defoliation is predicted as a function of the number of gypsy moth egg masses, the number of years since the beginning of the outbreak, susceptible species basal area, pine basal area, and total stand basal area.
Climate change and tree-ring relationships of Nothofagus menziesii tree-line forests
Authors: Cullen Louise E , Palmer Jonathan G , Duncan Richard P , Stewart Glenn H
Published: April 2011

To assess the sensitivity of New Zealand tree lines to climate warming, we compared the tree-ring growth characteristics and temperature relationships of silver beech (Nothofagus menziesii (Hook. f.) Oerst) at two elevations, ca. 1200 m (tree line) and ca. 1100 m. Modelled relationships between climate series and tree rings indicated that the main climatic control on tree growth was current summer temperatures. Nevertheless, temperatures during earlier seasons can influence tree growth, pointing to a complex relationship between radial growth and climate at tree line. Overall, the similarity in the growthtemperature relationships for trees at both elevations indicated that high-altitude N. menziesii forests should be useful for examining the impact of climate warming on tree growth. However, the level of common growth variation was greater in the below tree line chronologies, suggesting that other factors, including natural disturbance, may affect or compete with the influence of temperature on tree-ring growth at tree line. Despite the importance of summer temperatures for tree growth at or near tree line and the reported increase in summer temperatures since 1950 in New Zealand, ring widths have not increased in recent decades. We conclude, therefore, that in these N. menziesii tree-line forests there has been no detectable tree-ring growth response to climate warming.
Measuring and modelling the crown and light transmission characteristics of juvenile aspen
Authors: Pinno Bradley D , Lieffers Victor J , Stadt Kenneth J
Published: April 2011

Crown dimensions, crown leaf areas, and leaf area densities were determined on individual trees in 96 juvenile Populus tremuloides Michx. stands in central Alberta, Canada. Crown radius, height, leaf area, and leaf area density were well explained by stem diameter at 30 cm (D30). Leaf area index, estimated using the LAI-2000, reached a maximum of 4 m2·m2 in some stands by age 9 and decreased after age 25. Leaf area indices for the same stands, estimated by allometric relationships, were greater than 7 m2·m2. Horizontal overlap between adjacent tree crowns declined from 68 to 38% of crown width with increasing average D30 from 1.5 to 15.0 cm. These data were used to calibrate MIXLIGHT, a spatially explicit light transmission model, to predict the range of light conditions in the understory of juvenile stands. Light predictions were validated in 18 additional plots in which light transmission was measured. Measured light transmission ranged from 4 to 68% of above canopy light among sites and from 16 to 53% within a mapped site. MIXLIGHT predicted transmission well for average stand light levels (R2 = 0.80). For individual positions within the mapped stand there was a strong relationship between predicted and observed light (R2 = 0.92), but there was underprediction at high light and over at low light.
Roles of weathered bedrock and soil in seasonal water relations of Pinus Jeffreyi and Arctostaphylos patula
Authors: Hubbert K R , Beyers J L , Graham R C
Published: April 2011

In the southern Sierra Nevada, California, relatively thin soils overlie granitic bedrock that is weathered to depths of several metres. The weathered granitic bedrock is porous and has a plant-available water capacity of 0.124 m3·m3, compared with 0.196 m3·m3 for the overlying soil. Roots confined within bedrock joint fractures access this rock-held water, especially during late summer when overlying soils are dry. We sought to determine seasonal soil and bedrock water changes in a Jeffrey pine (Pinus jeffreyi Grev & Balf.) plantation and to examine concurrent effects on the water relations of Jeffrey pine and greenleaf manzanita (Arctostaphylos patula Greene). In 1996, plant-available water in the 75 cm thick soil was depleted by late June, with soil water potential (ψsoil) <2.2 MPa, but below 75 cm, bedrock water potential (ψbedrock) was still > 2.2 MPa. Thus, the bedrock, not the soil, supplied water to plants for the remainder of the dry season. Higher values of, and smaller fluctuations in, seasonal predawn pressure potential (ψpredawn) for Jeffrey pine indicated that it is deeply rooted, whereas active roots of greenleaf manzanita were interpreted to be mostly within the upper 100 cm. The extra rooting volume supplied by weathered bedrock is especially important to pine relative to manzanita.
Depth Effects and Genetic Influences on Injury Caused by Artificial Sea Water Floods to Loblolly and Slash Pine Seedlings
Authors: Land Jr. S. B.
Published: April 2011

Loblolly pine (Pinustaeda L.) and slash pine (Pinuselliottii Engelm.) seedlings from families of full-sib progenies were flooded with a 75% concentration of artificial sea water or with tap water for 2–4 days. The water potential and osmotic potential of the seedlings' needles decreased through 5 days of observations following the sea water flooding, and the contents of chloride and sodium ions increased. Injury and chloride content increased as depth of sea water above the surface of the soil increased. No injury occurred when seedlings were flooded with tap water to similar depths for the same period of time. For the particular families used, slash pine seedlings were more tolerant of sea water flooding than loblolly seedlings, and significant differences in tolerance among families within each species were obtained. Differences in rate of ion uptake and in needle water content were probably responsible for the effects of depth and genotype on injury.
Genetics of Graft Rejection in Douglas-fir
Authors: Copes Donald L.
Published: April 2011

Graft rejection in Douglas-fir was controlled primarily by additive genes. Heritability of graft incompatibility was 0.81. No significance for specific combining ability was found. A breeding program to develop highly compatible stocks should enable tree improvement workers to substantially reduce incompatibility losses within clonal orchards. Highly incompatible clones may have different or additional rejection factors which less incompatible clones do not exhibit.
Translocation of Dehardening and Bud-Break Promoters in Climatically 'Split' Douglas-fir
Authors: Timmis R. , Worrall J.
Published: April 2011

Forked Douglas-fir seedlings were exposed to warm (20 °C) and cold (2 °C) environments simultaneously, by inserting one branch in each environment. All received the same light conditions. Hardiness of foliage after 1–5 months was measured as the freezing temperature causing 50% visible injury in excised needles.The chilling stimulus for breaking rest and inducing hardiness was confined to the chilled branch, but the warm branch apparently transmitted a factor which prevented full hardening in the chilled one. A factor moving in the same direction also promoted flushing in branches chilled only at night from December to June (and receiving greenhouse temperatures and natural photoperiods by day). Factors from the expanding shoot caused loss of short-day-induced hardiness in previous year's foliage and stimulated cambial division. Chilling at night prevented the dehardening but did not prevent cambial activity. The dehardening factor was translocated to an opposite branch whereas movement of cambium stimulator was strictly basipetal.It is suggested that promoter–inhibitor levels controlling dormancy are independently regulated, and that a two-stage dehardening process might protect against premature loss of hardiness in nature. The simultaneous induction of cold acclimation and dehardening in the same plant provides material for comparing properties of hardy and nonhardy tissue.
Relationship Between the Starch Level at Budbreak and Current Shoot Growth in Abiesbalsamea L.
Authors: Little C. H. A.
Published: April 2011

Shading and transplanting procedures were used to vary springtime carbohydrate production and storage in 5-year-old balsam fir and Norway spruce seedlings. Current leader growth, and pre- and postbudbreak levels of starch, total sugar, and water in needles, stems, and roots were measured. Leader growth in seedlings shaded only before budbreak was similar to that in unshaded controls, although at budbreak the shaded seedlings had accumulated substantially less starch, the major form of reserve carbohydrate. However, seedlings shaded only after budbreak grew less than unshaded controls, despite similar starch contents at budbreak. Leader growth in seedlings lifted before budbreak and replanted when budbreak occurred in the field was the same as that in seedlings transplanted at field-budbreak, although the starch content was lower in the prebudbreak-lifted seedlings. The results indicate that current shoot growth in these conifers is independent of the level of reserve carbohydrate accumulated in the spring before budbreak.
Optimizing the Management of Uneven-aged Forest Stands
Authors: Adams Darius M. , Ek Alan R.
Published: April 2011

Two perennial problems in the management of uneven-aged forests are considered: (i) determination of the optimal sustainable distribution of trees by diameter class, i.e. stand structure, for a given initial stocking level, and (ii) the optimal cutting schedule for the conversion of an irregular stand to a target structure. It is shown, using examples for northern hardwood stands in Wisconsin, that both problems can be solved via mathematical programming techniques. The programming approaches utilize a set of nonlinear equation models for stand table projections which consider the interdependence of size classes within the stand. To illustrate procedures, optimal stand structures are found for a case where initial stand basal area is constrained to specified levels and the objective is to maximize value growth over the cutting cycle. A conversion cutting schedule is then determined for a case in which the objective is maximization of present worth. It is emphasized that both the optimal distribution and conversion problems can be generalized to consider a broad range of objective functions, lengths of cutting cycle, and constraints on the growing stock.
Low Temperature Damage to Dwarf Mistletoe Fruit
Authors: Baranyay J. A. , Smith R. B.
Published: April 2011

Early frost damage to dwarf mistletoe (Arceuthobium sp.) fruit was observed in the field, but the intensity of cold and duration of freezing temperatures were not recorded. In a controlled environment, exposure to −3.9 °C for about 2.3 h for lodgepole pine dwarf mistletoe (A. americanum Nutt. ex Engelm.) and for 2.0–4.8 h for hemlock dwarf mistletoe (A. tsugense (Rosend.) G. N. Jones) was necessary to cause permanent damage to the fruit. Field observations indicated that early fall frosts reduced the capacity of hemlock dwarf mistletoe to disperse seeds forcibly by 95%.
Jack Pine Nitrogen Fertilization and Nutrition Studies: Three Year Results
Authors: Weetman G. F. , Algar D.
Published: April 2011

The response of a 40-year-old even-aged jack pine (Pinusbanksiana Lamb.) stand to nitrogen fertilization was studied in four experiments.Smothering of the ericaceous ground vegetation layer with straw led to increased tree growth rates and improved N uptake. The application of calcium nitrate, ammonium nitrate, and urea at 112 and 448 kg N/ha was followed by analysis of the composition of extractable humus N, together with foliar and increment analyses. After a 3-year response period, there was evidence for the superiority of the ammonium nitrate form of N fertilizer over urea. The applications of urea appear to have been associated with possible N volatilization losses, and also inadequate urease activity in the thin dry humus layer which led to delayed N uptake by the trees. Calcium nitrate, although not an efficient fertilizer, was associated with appreciable growth responses, even though increased foliar and extractable humus N concentrations were not maintained.An optimum nutrition experiment utilizing repeated fertilization indicated that sustained foliar nutrient regimes can be maintained.The study indicated that growth increases were associated with increased unit needle weights as well as increased foliar N concentrations. A graphical technique which analyzes treatment responses, unit needle weight, and nutrient concentration, was used to screen response data, without waiting the customary 5-year period for stem increment response.
Seedling Shoot and Bud Development in Provenances of Sitka Spruce, Piceasitchensis (Bong.) Carr.
Authors: Pollard Douglas F. W. , Teich Abraham H. , Logan Kenneth T.
Published: April 2011

Growth and development of seedlings of ten provenances were compared in three investigations. The provenances ranged from Oregon to south-east Alaska and were collected for the I.U.F.R.O. International Sitka Spruce Provenance Experiment. The potential for seedling growth was studied by measuring (a) the rate of shoot growth and (b) the duration of shoot elongation. Growth rate was rather uniform, being only slightly faster among northern provenances. The duration of shoot growth, under artificial declining photoperiods was strongly influenced by latitude of origin. The critical photoperiods necessary for sustained growth in southern provenances were up to 4 hours shorter than those in northern provenances. In the third investigation development of the terminal bud was followed during the first 8 weeks. After a 4-week induction period buds attained macroscopic sizes with ca. 100 needle primordia. Northern provenances had up to 65% more primordia than southern ones. At 8 weeks, a strong but reversed relationship was evident, with southern provenances having up to 35% more than northern provenances. These observations indicate that latitude-correlated variations will be an important feature of the I.U.F.R.O. Experiment, with southern provenances performing especially well in southern trials. Potential advantages of southern provenances will be protracted periods of shoot growth in young seedlings and protracted periods of development of the primordial shoot in overwintering buds. However, where summer seasons are short, such advantages may not be realized.
The Distribution of Microorganisms Associated with Decay of Western Red Cedar
Authors: Kamp B.J. Van Der
Published: April 2011

The heartwood of old growth western red cedar (Thujaplicatai Donn.) on the British Columbia coast exhibits a rather consistent color pattern surrounding columns of decay. Surrounding the column of laminar decay lies a zone of brown stained wood; to the outside of this one finds a narrower layer of red stained wood, and the outer heartwood is straw-colored. Isolation of microorganisms demonstrated that whereas the outer heartwood was essentially sterile, the red and brown stained sound wood was inhabited by three fungi, two of which were restricted to the inner portion of the brown zone. The typical laminar decay appeared to be caused by Poriaalbipellucida Baxter which was isolated only from a narrow zone at the edge of the sound wood. The central decay column was inhabited by a large number of filamentous fungi, yeasts, bacteria, insects, and plant roots. These results support the hypothesis that decay of western red cedar involves a succession of organisms. Presumably the early invaders destroy the toxic natural extractives present in the heartwood.
Inoculations of Balsam Fir with Odontiabicolor: Early Establishment and Associated Microorganisms
Authors: Lachance Denis
Published: April 2011

Balsam fir growing on a site having two different soil moisture contents (the drier soil moisture content induced artificially) were inoculated with Odontiabicolor (Alb. & Schw. ex Fr.) Quél. It is shown that the fungus infected roots more readily than trunks, that trunk wounds at 137 cm (4.5 ft) above ground were as susceptible to infection as those at 30 cm (1 ft), and that infection percentages obtained 1 and 2 years after inoculation, although generally higher the second year, were not significantly different. Other fungi, commonly associated with discolored and decayed wood in balsam fir also infected the inoculation wounds, some more frequently root wounds (e.g. Coniophoraputeana, Trichoderma spp.), others trunk wounds (e.g. Retinocyclusabietis, Tympanis spp.). Amylostereumchailletii was isolated significantly more often from roots on wetter than drier soil conditions; Trichoderma spp. showed an opposite trend. O. bicolor apparently followed Graphium spp. at the infection site and was not affected by it as it grew into the wood. An apparent relationship also existed at the inoculation site between O. bicolor and Trichoderma spp.
Hypersensitive Reaction in Pinusarmandii Caused by Cronartiumribicola
Authors: Hoff R. J. , McDonald G. I.
Published: April 2011

A hypersensitive reaction is described in the needles of Pinusarmandii that developed in response to infection by Cronartiumribicola.
Environmental control of leaf water conductance in conifers
Authors: Running Steven W.
Published: April 2011

Diurnal measurements of leaf conductance, xylem water potential, temperature, humidity, and radiation were taken on six sites throughout Oregon. Xylem water potential was hypothesized to influence leaf conductance in two ways. First, predawn xylem water potential controlled the early-morning maximum leaf conductance of Pseudotsugamenziesii (Mirb.) Franco. Second, irrespective of predawn water potential, a threshold diurnal water potential was found. Whenever water potential of Pseudotsugamenziesii dropped below −20 bars (−20 × 105 Pa) during the day, a significant decrease in leaf conductance resulted. If the water potential threshold was not reached during the day, leaf conductance stayed at the morning maximum or decreased slightly in response to decreasing humidity.
Differences among Populas species in ability to form adventitious shoots and roots
Authors: Schier George A. , Campbell Robert B.
Published: April 2011

Differences in suckering from root segments and in rooting from sucker cuttings were studied among four species of Populus, including three poplars, P. angustifolia James, P. deltoides Bartr., and P. balsamifera L., and an aspen, P. tremuloides Michx. Places where suckers originated on root segments were more variable in the poplars than in the aspen. Whereas suckers developed in the aspen only from the periderm, suckers developed in the poplars from the periderm and from cambium exposed at the cut ends of segments and lateral roots. Poplar suckers arising from the periderm originated from preexisting suppressed buds embedded in the periderm. Suckers developed in the aspen from preexisting primordia. Lateral root formation from preexisting and newly initiated meristems on root segments was common in the poplars but rare in the aspen. The presence of lateral roots increased sucker growth, and the development of suckers and lateral roots responded to the inherent polarity of the root segment. Sucker cuttings from the poplars were generally superior in rooting capacity to those from the aspen.
Cartographie du risque de retrouver de la mortalité dans les forêts de sapin baumier attaquées par la tordeuse des bourgeons de l'épinette
Authors: Hardy Yvan J. , Dorais Louis G.
Published: April 2011

A hazard rating map is obtained in Quebec by superimposing the map of the annual damage caused by the spruce budworm, Choristoneurafumiferana (Clem.), during the past 4 years on that forecast for the next year. The various levels of risk are based on the physiological value of each year of foliage production and the ability of balsam fir, Abiesbalsamea Mill., to resist repeated budworm attacks. Applied to the forest of Quebec, this hazard map can lead to a more rational use of pesticides against the budworm.
The use of subjective probability assessments to predict forest fire occurrence
Authors: Cunningham A. A. , Martell D. L.
Published: April 2011

This paper addresses the problem of predicting forest fire occurrence. A simple methodology is developed to elicit information, from experienced fire managers, for deriving subjective probability assessments concerning the number of fires that will be reported in their districts each day. The approach is based upon the assumption that such individuals can identify and classify similar fire environments with satisfactory consistency. Using the concept of subjective probability, a methodology is developed for combining classified experience with a decision maker's initial assessment concerning assessor behavior. A scoring rule is used to measure the accuracy of the assessments. The results of an experiment which was conducted in northern Ontario during the 1973 fire season are presented.
Environmental factors affecting Sirococcus shoot blight of black spruce
Authors: Wall R. E. , Magasi L. P.
Published: April 2011

Pathogenic isolates of Sirococcusstrobilimts from Piceamariana were studied under laboratory conditions to determine the temperature, light, and humidity requirements for conidial germination, mycelial growth, pycnidial production, and infection of spruce seedlings. Conidial germination and mycelial growth occurred between 5 and 30 °C. The fungus survived temperatures of −10 °C, as well as outdoor winter conditions, for several weeks. Temperatures of 35 °C were lethal to spores and mycelium after exposure of 2 and 7 days, respectively. Light did not measurably affect conidial germination and mycelial growth but was necessary for pycnidial production. Infection of Piceamariana seedlings occurred in artificially inoculated seedlings enclosed in plastic bags to maintain a high humidity for at least 1 day after inoculation. Infection was greatest under a daily temperature cycle of 16–21 °C, less at 10–16 °C, and significantly reduced at 24–30 °C. At all temperature ranges, the percentage infection was greater under low light intensities (900–3900 lx) than under relatively high light intensities (4300 – 10 000 lx). It is concluded that warm sunny weather during the period of susceptibility would probably control this desease; protective measures are necessary only if frequent or prolonged periods of below-average temperatures and wet cloudy weather occur during the summer months.
Variation in diameter of central columns of discoloration in six hybrid poplar clones
Authors: Garrett Peter W. , Shigo Alex L. , Carter Jonathan
Published: April 2011

The percentage of stem diameter discolored in the center of hybrid poplar logs varied by clones. For the six clones studies, discoloration columns ranged in percentage of total stem diameter from 85.0 to 55.8.
Tree shoot elongation in northern Wisconsin and relationships with temperature and precipitation
Authors: Buech Richard R.
Published: April 2011

The relative amount of shoot elongation in the upper crowns of mature trees was studied in a forest community near Rhinelander, Wisconsin. Curves of the percentage of total elongation for the 1970 through 1973 growing seasons were similar to those previously reported for younger trees, but the elongation periods were generally shorter. Quercusrubra had the shortest period of elongation, followed by Acersaccharum. Tiliaamericana, Acerrubrum, Betulapapyrifera, Populustremuloides, and Abiesbalsamea in order of increasing duration. Comparisons were also made of the elongation patterns among species and years. Expected dates for the attainment of 10% elongation based on heat sums and year-day were compared with the observed dates. For all species except A. balsamea and A. saccharum, the comparison demonstrated the use of heat sums in predicting initial elongation.
Use of electrical resistance to detect Verticillium wilt in Norway and sugar maple
Authors: Tattar Terry A.
Published: April 2011

Resistance to a pulsed electric current was significantly less in xylem of Acersaccharum and A.platanoides discolored by Verticilliumalbo-atrum than in healthy xylem. Electrical detection of discolored tissues between the cambium and 1.5-cm depth in the xylem allowed detection of the Verticillium wilt in artificially inoculated A.platanoides before development of foliar symptoms. Electrical resistance of tissue discolored by V.albo-atrum was similar to that of tissues discolored as a result of wounding. A probe electrode for measurement of electrical resistance at specific depths from the cambium to a depth of 1.5 cm into the xylem is described.
Rapid viability tests and aging study of some coniferous pollen
Authors: Ching Te May , Ching Kim K.
Published: April 2011

Rapid viability tests of pollen were developed to facilitate hybridization in tree-breeding programs. Pollen constituents and membrane integrity, as measured by conductance, ultraviolet absorbance, and carbohydrate and amino acid content of leachate, were found to be significantly correlated with in vitro germinability of stored, air-dried pollen lots. A specific conductance of 20 μmho or less and an OD260 of 0.2 or less per 100 mg pollen per 30 ml water leached for 30 min at 25 °C appeared to be indices with which to select highly viable pollen lots of Douglas fir (Pseudotsugamenziesii), noble fir (Abiesprocera), and western hemlock (Tsugaheterophylla) in less than 45 min. These viability tests appear to be the direct measurement of the products of aging in pollen, and one cause of aging was found to be the preferential retention and activation of hydrolases while the total soluble protein is degraded.
Effect of insect growth regulators and fertilizers applied as foliar sprays during the egg stage of the sawfly Neodiprionsertifer
Authors: Fogal W. H. , Sullivan C. R.
Published: April 2011

Two insect growth regulators, a mixture containing about 25% Cecropia juvenile hormone with its geometrical isomers (AY-22342-3: Ayerst Research Laboratories, Saint-Laurent, Quebec) and a preparation containing 75% of the aromatic terpenoid ether, 4-ethylphenyl-6,7-epoxygeranyl ether (R-20458-B: Stauffer Chemical Co., Mountain View, California), were tested under field conditions for ovicidal activity against eggs of Neodiprionsertifer (Geoff.). Single egg clusters on Scots pine (Pinussylvestris L.) and whole red pine (P. resinosa Ait.) trees were sprayed to the drip point with formulations containing 0.1, 1, or 10 g/litre of insect growth regulator. AY-22342-3 reduced egg hatch at 10 g/litre on both tree species but was more effective in the red pine trial. R-20458-B did not reduce egg hatch significantly. Results with AY-22342-3 in the laboratory were about twice as effective as field trials. The application of fertilizers (urea, KNO3, or NH4NO3) accompanying a spray of AY-22342-3 on whole red pine trees does not enhance larval mortality. For trees receiving relatively intensive care, notably ornamentals and Christmas trees, the ovicidal activity of insect growth regulators might be useful as a means of preventing sawfly defoliation.
Effet du chaulage sur la croissance de l'épinette blanche plantée à Grand'Mère
Authors: Phu Truong Dinh
Published: April 2011

The effect of liming alone or in combination with N, K, and Mg on the growth of white spruce (Piceaglauca (Moench) Voss), on the nutrient status of needles of trees, as well as on the content of mineral elements in the soil, was studied. The study, carried out in 1972, indicated that the soil amendments applied in 1962 at Grand'Mère in a 36-year-old plantation at the rate of 336 kg hydrated lime, 115 kg N, and 93 kg K, with or without 22 kg Mg per hectare, gave significantly higher basal area increments than those in the controls. Without the inclusion of N and K, dolomite or hydrated lime alone or with Mg had no marked beneficial effect on the growth of white spruce 5 or 10 years after treatments. No appreciable residual effect on the nutrient status of needles could be established. However, the amendments had slightly increased the soil pH and the soil content of exchangeable Ca in the treated plots.
Effects of cutting intensity, deer browsing, and liming on Allegheny hardwood tree regeneration
Authors: McClenahen J. R. , Hutnik R. J.
Published: April 2011

Survival, height growth, and abundance of Prunusserotina Ehrh. and other species of tree reproduction were studied during two growing seasons after the trees were cut to residual basal areas of 0 (clear-cut), 16 (partial cut), and 28 (uncut) m2/ha. Portions of each cutting treatment were fenced to exclude deer and (or) amended with 0.91 t/ha of dolomitic limestone. Survival of advance P. serotina seedlings was best among initially older, taller stems. Mortality among 1st-year P. serotina seedlings was higher on clear-cut and uncut plots than on partially cut plots, but cutting had no effect on survival of seedlings older than 2 years. Acersaccharum Marsh, survival was poorest on clear-cuttings. The intermediate level of cutting initially favored a greater abundance of more species than either clear-cutting or no cutting. Rates of height growth of dominant P. serotina seedlings were greatest on clear-cuttings, less on partially cut plots, and lowest in uncut plots. Browsing by deer had a large but statistically nonsignificant effect on height of dominant reproduction after 6 years. Slash generally reduced abundance but enhanced height growth of seedlings. Overall, partial (shelterwood) cutting appeared to be a viable alternative to clear-cutting as a means for regenerating even-aged Allegheny hardwood stands.
Xylem translocation of amino acids from roots to shoots in cottonwood plants
Authors: Dickson Richard E.
Published: April 2011

Xylem sap produced by root pressure and collected from topped cottonwood (Populusdeltoides Bartr.) contained sugars, organic acids, amino acids, protein, and inorganic nutrients. Amino acids and NO3N were present at the highest concentrations. Total amino acids in xylem sap ranged from 3 to 10 mol m−3 and NO3N ranged from 7 to 10 mol m−3. When lower leaves were photosynthetically labeled with 14CO2, activity was rapidly translocated to roots and recycled to shoots. Within 6 h after labeling leaves, xylem exudate contained between 1 and 2 × 106 disintegrations min−1 cm−3. Most of the activity (50 to 70%) was in the amino acid fraction. Although nine amino acids contained some activity, more than 90% of the 14C was found in five common transport and storage amino acids: asparagine, glutamine, serine, alanine, and γ-aminobutyric acid. Glutamine contained 60 to 70% of the activity in the amino acid fraction 2 h after topping. Sugars, translocated from lower leaves to roots via the ploem, are converted to amino acids in roots and then translocated to the developing shoot via the xylem.
Comparative root system morphologies of seeded-in-place, bareroot, and containerized Douglas-fir seedlings after outplanting
Authors: Preisig C. L. , Carlson W. C. , Promnitz L. C.
Published: April 2011

Root systems of 5- to 8-year-old Pseudotsugamenziesii (Mirb.) Franco seedlings of natural, bareroot, and container origin were quantitatively analyzed to determine the effects of seedling source on root system morphology. Lateral root orientation was stressed.Container and planting constrictions on root system morphology were recognizable after outplanting; planted stock types were differentiated from seeded-in-place seedlings on the basis of root system morphology. Container and natural seedlings had less variation in root system morphology within stock type than bareroot stock. Root spiraling was so low in the Douglas-fir stock types studies that it is not likely to affect tree stability. There was no overall effect of root system morphology on height of seedlings around 6 years of age.
Electrical resistance as a guide to thinning sugar maples
Authors: Shortle W. C. , Abusamra J. , Laing F. M. , Morselli M. F.
Published: April 2011

The electrical resistance (ER) of the cambial zone of sugar maples (Acersaccharum Marsh), growing in a stand used for sap production, was measured with a pulsed electric current meter. Trees of relatively low ER grew faster than those of relatively high ER and produced sap with equivalent sugar content.
Organic matter and chemical element dynamics in an aspen woodland soil
Authors: Lousier J. Daniel , Parkinson Dennis
Published: April 2011

Temporal and spatial dynamics of organic matter and mineral elements were studied in an aspen woodland floor in southwestern Alberta, Canada. The average depths of the layers comprising the organic horizon were as follows: L, 0–2 cm; F, 2–4 cm; H, 4–7 cm; and Ah, 7–8 cm. The average annual amounts of organic matter in the soil layers were the following: L, 10.3 × 103 kg ha−1 (range 8.0–16.4); F, 18.2 × 103 kg ha−1 (13.2–24.5); H, 31.5 × 103 kg ha−1 (24.0–40.4); and Ah, 4.2 × 103 kg ha−1 (3.8–5.0); the total weight of soil organic matter was 64.2 × 103 kg ha−1 (49.0–86.3). The H layer accounted for 50% of the soil organic matter; total soil organic matter, to a depth of 8 cm, constituted about 0.30 of the total living above-ground plant biomass. There were no evident statistically significant seasonal fluctuations of organic matter in any of the organic layers; the turnover rate of the soil organic matter was 0.08 year−1 and the mean residence time was 12.5 years.The concentrations of Ca, Mg, P, and N generally decreased with profile depth, while K, Fe, Mn, and Na increased in concentration. Zinc concentrations showed no obvious trend but it did appear that Zn might be concentrated in the F and Ah layers. The orders of abundance of elements in the soil layers were as follows: L,  Ca > N > K > Mg > P > Fe > Zn > Mn > Na > Cu; F, Ca > N > Mg > K > Fe > P > Zn > Mn > Na > Cu; H, Ca > N > Fe > K > Mg > P> Na > Mn > Zn > Cu; Ah, Fe > N > K > Ca > Na > Mg > P > Mn > Zn > Cu; total, Ca > N > Fe > K > Mg > Na > P > Mn > Zn > Cu. Maximum weights of Ca, N, Mg, and P were found in the H layer, whereas K, Fe, Zn, Mn, Na, and Cu were most abundant in the Ah. There was some indication that the amounts of some elements fluctuated positively or negatively with rainfall and (or) soil moisture levels. Based on limited input data for the elements, turnover times were calculated and compared with literature values.
A study of progressive stages of discoloration and decay in Malus using scanning electron microscopy
Authors: Blanchette Robert A.
Published: April 2011

Scanning electron microscopy has elucidated the roles of microorganisms during various stages of discoloration and decay in living apple trees Malussylvestris Mill. Disks were removed sequentially at 30-cm intervals up the tree from the bases of decayed trunks into clear sapwood from ten 20- to 30-year-old (Red Delicious) apple trees variously affected by internal decay. Evidence for a microbial succession and morphological changes in cell constituents was observed. Bacteria, yeasts, and other nonhymenomycetes (e.g., Cytospora spp.) appeared to be primary colonists of discolored tissues, which altered cell wall components, and degraded wound-initiated vessel plugs. Basidiomycetous hyphae were observed only in tissues where amorphous vessel deposits had been degraded by pioneer microorganisms. Associations of secondary bacteria and yeasts with wood-destroying hymenomycetes, indicating a mutualistic existence, were frequent. Decay was of the white rot type with numerous crystalline structures observed in regions of advanced decay.
Results of spraying Bacillusthuringiensis 2 consecutive years over balsam fir stands damaged by spruce budworm
Authors: Smirnoff W. A.
Published: April 2011

In 1977 and 1978, seven 40-ha blocks mostly composed of balsam fir (Abiesbalsamea (L.) Mill.) were treated with combinations of Bacillusthuringiensis formulations of three bacillus concentrates, from different producers, and two carriers, sorbitol and sodium dihydrogen phosphate. Proper calibration of the boom and nozzle spray system of a Grumman Ag Cat aircraft ensured sufficient and homogeneous dispersion of the bacillus. Larval mortality and tree defoliation observed varied according to the foliage potential and population levels before treatment. In treated blocks, current-year growth defoliation varied between 35.5 and 99.5%, and between 7.4 and 47.1% in 1977 and 1978, respectively. In untreated blocks, it varied between 94.8 and 100%, and between 81.8 and 100% in 1977 and 1978, respectively. In 1977, in treated blocks, foliage potential of balsam fir showed a 31.5 to 100% increase while in untreated blocks a 10.5 to 47.0% decrease was noted. In 1978, in treated blocks much of the current-year growth was preserved and 100% foliage potential was reestablished.
Estimation of tree growth losses caused by pest activity
Authors: Thomson A. J. , Sickle G. A. Van
Published: April 2011

An improved method of quantitative evaluation of pest-caused reduction of tree growth is described. Radial and height growth rates were measured from discs along the bole of the tree, and growth losses were evaluated by a computer program (IMPACT). The method is independent of site characteristics or competition effects. Use of the method was demonstrated for growth losses in Pseudotsugamenziesii attributable to defoliation by Choristoneuraoccidentalis, and with slight modification it may be applied to a range of tree-pest systems. A three-dimensional graphical procedure was used to display the growth pattern.
Barrier zone anatomy in red pine roots invaded by Heterobasidionannosum
Authors: Tippett Joanna T. , Shigo Alex L.
Published: April 2011

Resin production and decay were localized or, more specifically, compartmentalized in roots of Pinusresinosa Ait. invaded by Heterobasidionannosum Fr. Bref, (formerly Fomesannosus (Fr.) Krast). Distinctive tissues constituted the barrier zone which separated the resin-impregnated or decayed wood from the younger rings of normal, unaffected wood.The barrier zone tissues included distinctive tangential bands of parenchyma, many resin ducts, and disordered abnormal tracheids. The parenchyma cells of the barrier zone were thin walled and unlignified, and contained polyphenols. These cells were nucleate and remarkably similar to the secondary phloem parenchyma once fully differentiated.The barrier zone was most obvious when observed in close proximity to a site of injury or fungal colonization. However, the barrier zone appeared as a complete ring in many of the roots observed.
Ethanol and α-pinene as synergists for the aggregation pheromones of two Gnathotrichus species
Authors: Borden J. H. , Lindgren B. S. , Chong L.
Published: April 2011

Gnathotrichusretusus (LeConte) of both sexes were significantly more responsive to traps baited with S-(+)-sulcatol whenever ethanol was also present as a bait. Ethanol and α-pinene together acted as synergists for male G. sulcatus (LeConte) response to (±)-sulcatol. There was no synergistic effect on female response and no interaction between trap form and synergistic for G. sulcatus. Use of ethanol and α-pineneas synergists for (±)-sulcatol in a pest management program for G. sulcatus would enhance the male catch and thus reduce the possibility of uncaptured males creating competing pheromone sources.