bluuebunny/crossref_metadata_2025 huggingface dataset:
Stemflow in a Multi-storied Aspen Community
Authors: Clements John R.
Published: July 2007

This paper presents mathematical equations describing the relationships between the amount of stemflow per canopy layer per storm and the amount of gross rain per storm for four different canopy layers in a multi-storied forest community. The curves representing the relationships were curvilinear; for three of the canopy layers stemflow per storm increased at an increasing rate as gross rain per storm increased, approaching a constant rate of increase. Numerical values of the equation coefficients varied with canopy level in the forest stand profile and with variations in vegetal structure within the forest community. The lowest canopy in the vegetal profile, a fern canopy, had the most marked effect on rainfall redistribution.
Lethal and Nonlethal Effects of the Organic Horizons of Forested Soils on the Germination of Seeds from Several Associated Conifer Species of the Rocky Mountains
Authors: Daniel T. W. , Schmidt Josef
Published: July 2007

The study tests whether the lethal effect of overwintering Engelmann spruce seed in its O-horizon affects Douglas-fir, lodgepole pine and subalpine fir seeds and whether the O-horizons of the three associated species have the same lethal effect on seeds. All seed treatments of each species were stratified in petri dishes in the pure O-horizon (unsterilized and autoclaved) of each species. Seed treatments were untreated, 10% slurry of 50% Captan and powdered 75% Captan.All untreated seeds demonstrated the lethal quality of unsterilized Engelmann spruce O-horizon. Its effects on untreated seeds and powder treated seeds were as follows: Engelmann spruce seed 3.5 and 77.3% (germination of untreated and powdered respectively), subalpine fir seed 1.3 and 20.8, Douglas-fir seed 9.5 and 84.8 and lodgepole pine seed 11.9 and 85.7. Subalpine fir O-horizon was lethal to its own seeds but only moderately harmful to seeds of other species. Douglas-fir O-horizon had a significant adverse effect on its own seeds and was only moderately harmful to seeds of other species. Lodgepole pine O-horizon was almost neutral to all seeds. Autoclaving of the O-horizons and powder treatment of seeds produced similar results.
Acid Soluble Nucleotides and Ribonucleic Acids from Germinating Jack Pine Seeds
Authors: Durzan D. J. , Pitel J. , Ramaiah P. K.
Published: July 2007

In germinating pine seedlings, acid soluble nucleotides, initially rich in AMP, accumulated, and were increasingly dominated by ATP. By 7 days, when hypocotyls were green but still dependent on the female gametophyte, the percentage of adenine nucleotides declined as other nucleotides increased. At 11 days, when gametophytic reserves were depleted, and seedlings were exposed to 32P- phosphoric acid, adenine nucleotides accounted for over 70% of the recovery of 32P from the nucleotide fraction.In seedlings, total RNA per unit weight increased to the 6th day, then levelled off. Comparison of electrophoretic mobilities of pine RNA on 2.5% polyacrylamide gels with ribosomal RNA from other sources revealed the following main types based on estimated molecular weights: 1.3, 1.1, 0.7, and 0.56 × 106 daltons, corresponding to 25S, 23S, 18S, and 16S, respectively. On 10% polyacrylamide gels, the mobility of low molecular weight pine RNA was similar to that of yeast tRNA. The 1.3 and 0.7 × 106 dalton fractions, representing ribosomal RNA, contributed 60–90% of the total RNA. During germination, the ratio of 1.3 to 0.7 × 106 RNA dropped from 2.4 to 1.7 and reciprocated the pattern for water content of the seedling.32P was incorporated mainly into the 25S and 18S RNA by 11-day-old seedlings, indicating that synthesis of ribosomes was a major event in growing seedlings. During germination, the synthesis of RNA corresponded to an increase of total RNA detected cytochemically and to an increase of new cytoplasm with more ribosomes, as observed previously with hypocotyl cells by electron microscopic procedures.
The Influence of a Stem Discontinuity on Xylem Development in Norway Spruce, Piceaabies
Authors: Steucek G. L. , Kellogg R. M.
Published: July 2007

Norway spruce stems were artificially weakened by cutting a hole through them. The wood subsequently formed near the discontinuity was observed after six growing seasons following the cutting. Enhanced xylem development persisted in the zone of the discontinuity long after wounding and partial girdling stimuli could be considered to have an effect. This evidence supports the mechanistic hypothesis of stem-form development because mechanical stress level along the stem, originating from wind loading, would be greatest in the region of the discontinuity.
Lateral Root Pruning of Sitka Spruce and Western Hemlock Seedlings
Authors: Eis S. , Long J. R.
Published: July 2007

Roots of Sitka spruce (Picea sitchensis) and western hemlock (Tsugaheterophylla) seedlings were side pruned in nursery beds at semimonthly intervals to produce dense and compact root systems. Root pruning early in the growing season stimulated the growth of existing roots and also initiated new roots. The densest root systems were produced by pruning before the end of June. However, because of the short length of lateral roots on seedlings early in their second growing season, pruning equidistant between rows 18 cm apart was ineffective. The best compromise appeared to be to prune spruce at the beginning of July, and hemlock around the middle of July. Earlier pruning equidistant between rows can be effective on larger seedlings during their third growing season. If early pruning is carried out on 2 + 0 seedlings, a pruning distance of about 6 cm from the row is recommended.
Effects of Deicing Salt on Eastern White Pine: Foliar Injury, Growth Suppression and Seasonal Changes in Foliar Concentrations of Sodium and Chloride
Authors: Hall R. , Hofstra G. , Lumis G. P.
Published: July 2007

Effects of deicing salt on eastern white pine (Pinusstrobus L.) were studied in the field and in the laboratory. Studies in controlled temperature chambers showed that solutions of deicing salt sprayed onto 4-year-old trees induced symptoms of foliar browning similar to those observed on trees growing near highways. Symptoms developed at 15 °C but not at 1.5 °C. The amount of injury that developed after 3 weeks at 15 °C appeared to be directly related to the concentration of sodium and chloride in the leaf tissue. Repeated sampling of foliage from trees adjacent to highway 401 between May 1970 and May 1971 revealed that foliar concentrations of sodium and chloride declined from abnormally high values (up to 1%) in May to 'normal' levels (0.02–0.1%) by August. The rate of loss was proportional to the foliar concentration of these ions. Growth of these trees, measured as bud weight, needle length, needle dry weight, needle bundles per leader, and leaf length, was suppressed on the side of trees exposed to the highway, but this suppression diminished as distance from the highway increased. Annual radial increments to the trunk were appreciably smaller in trees close to the highway than in trees further away. These results support the concept that deicing salt spray injures leaves and reduces growth of eastern white pine growing adjacent to highways that receive deicing salt in the winter.
Palsas and Peat Plateaus in Central Manitoba and Saskatchewan
Authors: Zoltai S. C.
Published: July 2007

Twenty-six peat plateaus and eight palsas were examined near Flin Flon, Manitoba at the southern limit of discontinuous permafrost. Peat plateaus in different developmental stages were identified on the basis of their morphology. The permafrost is entirely within the peat in all peat plateaus within the study area, but extends into mineral subsoil under all palsas examined. Doming in peat plateaus is largely explained by volume change due to change from unfrozen to frozen stage, and by buoyancy of the frozen mass floating on unfrozen peat. The occurrence of aggrading and degrading peat plateaus in the same area indicates that all developmental stages are permitted by the present climate.
Forage Yield and Browse Utilization on Logged Areas in New Brunswick
Authors: Telfer E. S.
Published: July 2007

Studies of forage yield, standing stock of browse, and utilization of browse by moose (Alcesalcesamericana Clinton), deer (Odocoileusvirginianusborealis Miller), and hares (Lepusamericanusstruthopus Bangs) were made on commercially cut forest areas of five age classes in New Brunswick. The 6-year old cuts yielded most forage, while the 10–12-year old cuts had the greatest standing stock. Older cuts produced less forage and had smaller standing stock. Moose and white-tailed deer fed most heavily on the 2-year old cuts; hares on the 15–18-year old cuts, probably because more suitable shelter was available. The three browsers shared a preference for some species but the total weights they ate were small compared to the amounts available.
The Influence of Wood Harvesting on the Nutrient Status of Two Spruce Stands
Authors: Weetman G. F. , Webber B.
Published: July 2007

Calculations are presented on the quantities of N, P, K, Mg and Ca in the soil and above-ground portions of two spruce-pulpwood stands on sites of average fertility in northern and southern Quebec. The magnitude of the depletions of these nutrients from the site, in full-tree and tree-length methods of logging, are compared with the available and total quantities of them in the soil. The ranges of values, from the literature, for the input of these nutrients in dust and precipitation, and the losses in leaching, are presented and discussed in relation to the logging losses.It is concluded that on both sites it is unlikely that full-tree logging will result in any reduction in growth, due to nutrient removal, during the second rotation of trees. However, nutrient depletion due to full-tree logging, particularly with respect to Ca, K and N, may require correction by means of fertilizers in forest ecosystems of marginal fertility. These are usually either dry sites with low reserves of organic matter and low exchange capacity or wet sites with excessive accumulations of organic matter. The need for further detailed studies of the nutrient cycle in different forest ecosystems is stressed.
An Evaluation of Some Effects of Bole and Branch Pulpwood Harvesting on Site Macronutrients
Authors: Boyle J. R. , Ek A. R.
Published: July 2007

Macronutrient removals by conventional and bole and branch harvesting systems were evaluated on a mixed hardwoods site in north central Wisconsin. Samples indicate that minimum soil reserves of nitrogen, phosphorous, and magnesium are 5–15 times greater than the amounts removed by a harvest cut at the end of a 45-year rotation. Currently available reserves of potassium and calcium are 1–3 times greater than harvest removals. Estimates indicate that natural inputs will supplement these reserves over such rotations, but may not balance drains over substantially shorter rotations. Nutrient cycling and possible replenishment of elements are discussed along with silvicultural implications.
White Spruce Cone Production and Prediction of Cone Crops
Authors: Eis S. , Inkster J.
Published: July 2007

In September preceding the seed year, reproductive buds of white spruce can be recognized with the naked eye. The numbers of ovulate buds are a good indication of the prospective cone crop. A method of sequential sampling on a small number of trees, which enables a prediction of cone crop potential on a stand or regional basis, is presented. This advance information facilitates planning of seedbed preparation for natural regeneration, seed collection and artificial reforestation.
Line-throwing Gun and Cutter for Obtaining Branches from Tree Crowns
Authors: Collis D. G. , Harris J. W. E.
Published: July 2007

A technique that has proved successful for collecting branches from tall trees involves shooting a nylon monofilament line over a tree and drawing up a device to clip branches. Several shoulder guns, firing various sized line-pulling missiles to different heights, were tested. A branch clipping device was maneuvered into the crown by two men, each hauling on a line. It cut or broke off a branch when one end of the line was pulled.The method eliminates destructive felling and hazardous climbing, and can reach higher than ladders or pole pruners. It can be employed in collecting insect and disease samples, scions and cones, and for marking tree tops for aerial work.
Short-rotation Trembling Aspen Trees (Populustremuloides Michx.) for Kraft Pulp
Authors: Hunt K. , Keays J. L.
Published: July 2007

A combined sample from 22 6-year-old trembling aspen trees (Populustremuloides Michx.) was pulped by the kraft process and compared to samples from the same area of two trees aged 16 and one tree aged 53 years. Average unscreened pulp yields at permanganate No. 14 were 55.3, 59.8, and 57.4% (based on o.d. wood) for 6-, 16-, and 53-year-old samples, respectively. Breaking lengths and burst factors were similar for pulps from all three age groups at C.S.F. 300 ml. Tear factor was lower for pulp from the 6-year-old trees. These and other data from the literature indicate that aspen can be pulped by the kraft process at rotations down to at least 6 years, and the pulps resulting have yield and strength values within the range found for more mature trembling aspen.
Prediction of Frost Hardiness in Douglas Fir Seedlings by Measuring Electrical Impedance in Stems at Different Frequencies
Authors: Driessche R. van den
Published: July 2007

Frost hardiness of Douglas fir (Pseudotsugamenziesii Mirb. Franco.) plants was assessed by a range of freezing tests in three experiments. In experiments 1 and 2 plants were grown in different temperature regimes, under short days, for 8 weeks to induce different levels of frost hardiness. In experiment 3, plants remained in the open and were sampled on 21 occasions through one year.Comparison of stem impedance measurements made at 1 kHz, 4.5 kHz, and 1 MHz, before and after freezing tests in experiments 1 and 2, indicated survival of individual plants was well predicted by post test measurements. The postfreezing test 1 kHz/1 MHz ratio distinguished between dead and surviving plants with the smallest number of measurements. Both this ratio and 4.5 kHz impedance provided similar conclusions about treatment effects, which agreed satisfactorily with conclusions from survival data. Impedance ratios of 1 kHz/1 MHz measured in stems after freezing tests accurately predicted survival in experiment 3. Seasonal changes in ratio, determined after freezing to a particular temperature, paralleled seasonal change in plant frost hardiness and was significantly correlated with exposure to cold during 14 days prior to measurement.
Corky Root Disease of Douglas-fir: Relation of Xiphinemabakeri Nematodes to Symptom Severity, and Observations on Seedling Tissue and Soil Nutrients
Authors: Sutherland Jack R. , Sluggett L. J.
Published: July 2007

Four-month-old Douglas-fir Pseudotsugamenziesii Mirb. (Franco) seedlings were collected from a coastal British Columbia forest nursery, and the number of Xiphinemabakeri nematodes per cubic millimeter of root volume was related to the severity of several corky root disease symptoms. The strongest relationships existed between nematode root populations and seedling epicotyl length, and the number of first-order lateral roots over 5 mm long. Diseased and healthy seedlings were analyzed for tissue nutrients. Healthy seedlings contained significantly more nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and chlorophyll, and significantly less calcium (Ca) than diseased plants. The nutrient content of soil samples collected at 0–4, 4–8, 8–12, and 12–16 cm depths from areas with or without diseased seedlings was determined. The N, Ca, Mg, and conductance levels of soils from the healthy seedling area were significantly greater than those from the disease-infested area, but no other pertinent differences, relating to disease occurrence, were found in the nutrient content of samples from the different depths, and no relevant disease class - sampling depth interactions were detected. Several factors, which help explain the recent increased incidence of corky root disease, are discussed.
Nitrogen Concentrations in the Current Foliage and in Fresh Litter of Fertilized Black Spruce Stands
Authors: Mahendrappa M. K. , Weetman G. F.
Published: July 2007

In three separate fertilization experiments in black spruce stands, the concentration of nitrogen in foliage collected from the trees and the needles of litter samples gathered from screens on the soil surface were closely correlated. Nitrogen concentrations in litter samples collected in October were more closely correlated with nitrogen level in the trees at that time of year than the litter samples gathered in May. Nitrogen in the twigs was weakly correlated with foliar nitrogen status. Nitrogen concentrations in litter samples collected in May were highly correlated with the foliar nitrogen measured during the previous year. The coefficient of correlation differed between the stands. Regression coefficients were not time-stable in all the stands.
Height of Crown Scorch in Forest Fires
Authors: Wagner C. E. Van
Published: July 2007

A relation between fire behavior and crown scorch height is derived from measurements on 13 experimental outdoor fires. The range of data includes fire intensities from 16 to 300 kcal/s-m, and scorch heights from 2 to 17 m. The results agree with established theory that scorch height varies with the 2/3 power of line-fire intensity. The effects of air temperature and wind speed on scorch height are treated as well. The derived relations could be useful to those interested in prescribed burning under a crown canopy, ecological response of trees to fires of varying intensity, and timber losses following forest fires.
Microelement Status of Balsam Fir in the Southern Laurentians
Authors: Allaire D. , Bernier B. , Laflamme Y.
Published: July 2007

Concentrations of Fe, Mn, Zn,Cu, and Al in first-season needles of balsam fir (Abiesbalsamea (L.) Mill.) averaged 46, 1180, 56, 6.7, and 205 p.p.m., respectively, for 200 mature trees sampled in 20 fir stands distributed on three different soil series. There were no significant differences in element concentrations among these three groups. Concentrations of B, Cl, and Mo averaged 18.9, 385, and 0.11 p.p.m., respectively, from 110 trees of 11 stands. Manganese concentrations increased consistently with needle age; with few exceptions, Fe, Zn, and Al concentrations were unaffected by needle age. Results from a single stand indicated no significant variation due to crown position, except for Mn level which increased significantly from the lower to the upper crown. Levels of Fe, Mn,Zn, Cu, and Al in first-season needles remained fairly constant over a 10-week period in fall. Sampling guides are provided for future work.
Phytosociology of Peatlands in Central Newfoundland
Authors: Pollett Frederick C. , Bridgewater P. B.
Published: July 2007

Using Zurich–Montpellier methodology the peatlands of central Newfoundland were classified into eleven provisional associations varying from poor ombrotrophic bog to eutrophic fen. A key is appended to aid in determination of sites in the field.
The Rate of Silt Accumulation in the Lower Peel River, Northwest Territories
Authors: Strang R. M.
Published: July 2007

Estimates of the rates of silt accumulation in the lower Peel River were derived from excavated root systems of white spruce and from radiocarbon dating of buried detritus. They indicate that average annual accumulation is of the order of 1 cm.
Seasonal Variation in Sucker Production from Excised Roots of Populustremuloides and the Role of Endogenous Auxin
Authors: Schier George A.
Published: July 2007

Seasonal variation in number of suckers produced from root cuttings of three clones of trembling aspen (Populustremuloides Michx.) was related, in a negative manner, to the quantity of endogenous auxin in the roots when collected. The mean number of suckers per cutting varied with the clone of origin and time of collection.
The Size of Trembling Aspen (Populustremuloides Michx.) Clones in Manitoba
Authors: Steneker G. A.
Published: July 2007

Delineation of trembling aspen (Populustremuloides Michx.) clones in a 40-year-old aspen stand at Riding Mountain National Park (RMNP) and a 25- to 50-year-old aspen stand at Agassiz Forest Reserve (AFR), Manitoba, has shown that at RMNP clone size averages 0.20 acre (0.08 ha) and at AFR 0.015 acre (0.006 ha). Largest clone mapped at RMNP was 3.80 acres (1.54 ha) and at AFR 1.24 acres (0.5 ha). Although soils are heavier and the amount of ground vegetation is greater at RMNP, the clone size of the respective areas appears unrelated to present site factors.Interclonal variation in growth characteristics makes necessary the sampling of several clones when undertaking inventory and site productivity studies. In stands such as in RMNP where relatively large clones are found it is recommended that either transect plots or a larger than normal number of conventional plots are used to ensure that the required number of clones is sampled. In stands similar to those at AFR where clone size is small no special sampling modifications are required.
Spruce Beetle Aggregated by the Synthetic Pheromone Frontalin
Authors: Dyer E. D. A.
Published: July 2007

Frontalin, a synthetic attractant developed from the southern pine beetle (Dendroctonusfrontalis Zimm.), induced spruce beetle (D. rufipennis Kirby) attacks on preselected spruce trees destined for harvest, and adjacent trees. If baited trees were treated with insecticide, spruce beetles and predators (Thanasimusundatulus Say) were killed. Female Dendroctonus predominated on frontalin-baited trees. Some baited trees, unprotected by insecticide, were killed by beetle attacks but many resisted attacks and prevented beetle broods from developing. Green windfall trees were attacked whether or not frontalin was used on adjacent standing trees. Distance between attractant, and attacked unbaited trees appeared to be related to tree size.
Intensive Culture Increases Growth Without Affecting Wood Quality of Young Southern Pines
Authors: Schmidtling R. C.
Published: July 2007

Fertilization and cultivation before and after planting greatly increased 9-year growth and yield of longleaf (Pinuspalustris), slash (P. elliottii), and loblolly pines (P. taeda). Intensive culture did not decrease specific gravity or fiber length of the juvenile wood. In loblolly pine, genetic variation was found in response to intensive culture.
Genetic variation in susceptibility of Abiesbalsamea to Mindarusabietinus
Authors: DeHayes Donald H.
Published: July 2007

A northern Vermont provenance test containing 1 Fraser fir (Abiesfraseri (Pursh) Poir.) and 21 balsam fir (Abiesbalsamea (L.) Mill.) provenances was attacked by the balsam twig aphid (Mindarusabietinus Koch.) during 1977 and 1978. Balsam fir from eastern provenances had 15–60% greater incidence of attack and averaged nearly twice the crown injury than did that from western provenances. Trees from an Indian Lake, NY, provenance were injured most with an average of 27 and 62% of current-year shoots injured during the 1977 and 1978 infestations. Trees from an Isle, MN, provenance were injured least with an average of 2 and 9% of current year shoots injured during the 2 years. The relative distribution of injury among provenances was similar from year to year. Fraser fir suffered little or no injury and appears to avoid twig aphid attack when planted in the north because it begins growth after the aphid population has peaked. The concentration of β-phellandrene in twigs was strongly correlated with twig aphid injury in balsam fir, whereas height, date of budbreak, needle length, and concentrations of other monoterpenes were weakly or only indirectly correlated with twig aphid injury.
Influence of explant selection on the shoot-forming capacity of juvenile tissue of Pinusradiata
Authors: Aitken Jenny , Horgan Kathryn J. , Thorpe Trevor A.
Published: July 2007

The shoot-forming capacity of Pinusradiata D. Don juvenile explants under tissue culture conditions was examined. Three types of explant were used: whole embryos; cotyledons excised from whole embryos which had been cultured for 1 week on the shoot initiation medium; and cotyledons excised from 1-week-old aseptically germinated seeds. The average number of rootable shoots produced per seed in 12–13 weeks was 9 for excised embryos, 18 for their separated cotyledons, and 180 for the cotyledons from germinated seeds. Induction of a smooth-surfaced, yellow–green, nodular meristematic tissue appears to be a requirement for the formation of large numbers of adventitious shoots. By extending the culture period from 12 to 24 weeks more than 1300 shoots were formed from the cotyledons of one germinated seed. To date, no other conifer tissue culture method has been reported to give such a large number of adventitious shoots of the same clone in a first generation.
Variability in ectomycorrhizal development and growth among isolates of Pisolithustinctorius as affected by source, age, and reisolation
Authors: Marx Donald H.
Published: July 2007

Twenty-one isolates of Pisolithustinctorius (Pers.) Coker and Couch of different ages and from different tree hosts and world locations were initially tested for ectomycorrhizal development on Pinustaeda L. seedlings in a growth room. Three oak isolates from the United States and seven pine isolates from the United States, Brazil, and Australia (1 – 17 years old) formed few or no ectomycorrhizae. Eleven remaining pine isolates (1 – 6 years old) collected in Taiwan, France, and nine locations in the United States formed abundant ectomycorrhizae.Reisolates were obtained from the above ectomycorrhizae formed by the original isolates. In pure culture on agar medium, most original isolates grew as fast or faster than the companion reisolates. Individual isolates differed greatly, however, in growth response at various temperatures; these differences were unrelated to age of culture or reisolation.In a nursery experiment, there were large differences among eight isolates and nine reisolates in degree of ectomycorrhizal development on P. taeda seedlings. Reisolation significantly improved ectomycorrhizal development of three original isolates (4 – 7 years old) but not others. There was no relationship between rate of growth in agar medium and capacity of isolates or reisolates to form ectomycorrhizae. The significance of age, host origin, and world location on variation in Pisolithustinctorius is discussed.Vingt et un isolais de Pisolithustinctorius (Pers.) Coker et Couch d'âges différents, provenant d'arbres-hôtes et de lieux géographiques distincts, sont d'abord étudiés quant à leur développement ectomycorhizien sur des semis de Pinustaeda L. en chambre de croissance. Trois souches isolées à partir de chênes aux États-Unis et sept souches isolées à partir de pins aux États-Unis, au Brésil et en Australie (agées de 1 à 17 ans) ne forment que peu ou aucune ectomycorhize. Les 11 autres souches (agées de 1 à 6 ans) qui proviennent de Taiwan, de France et de neuf endroits aux États-Unis, forment de nombreuses ectomycorhizes.
Ultraviolet-B radiation effects on early seedling growth of Pinaceae species
Authors: Kossuth Susan V. , Biggs R. Hilton
Published: July 2007

Seven coniferous species were grown in the Duke University phytotron under five ultraviolet-B (UV-B = 280–320 nm) radiation regimes for 11 weeks. The irradiation regimes were 765, 680, 637, 310, and 28 mW•m−2 as summed over the 280–320 nm UV-B waveband. The UV-B radiation source was FS40 Westinghouse sunlamps filtered with cellulose acetate for four treatment irradiation levels and clear Mylar for the control. Biomass production of lodgepole pine (Pinuscontorta Dougl.), loblolly pine (Pinustaeda L.), noble fir (Abiesprocera Redh.), ponderosa pine (Pinusponderosa Laws.), and slash pine (Pinuselliottii Engelm.) was significantly reduced at the highest UV-B radiation level and somewhat less at the lower levels. These species were rated as slightly susceptible (5–25% reduction in biomass). Biomass production of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was unaffected, and white fir (Abiesconcolor (Gord. and Glenn.) Lindl.) biomass was increased significantly by UV-B radiation at 310, 637, and 680 mW•m−2 UV-B radiation levels. Root weight tended to be reduced more than shoot weight, thereby decreasing root:shoot ratios significantly in certain UV-B regimes. Leaf area declined significantly with increasing UV-B radiation for all species except white fir and Douglas-fir. At the higher UV-B irradiance levels, height was significantly reduced when compared with the Mylar control on loblolly, lodgepole, ponderosa, slash pines, and noble fir, respectively. Height of Douglas-fir was not altered and height of white fir was increased significantly at the lowest level of UV-B radiation tested.
Early genetic differentiation of sugar maple by accelerating seedling growth
Authors: Wood Bruce W. , Hanover James W.
Published: July 2007

A method is described for accelerating growth of sugar maple (Acersaccharum Marsh.) seedlings for early progeny and provenance evaluation and plantation establishment. Outdoor nursery production methods produced relatively small seedlings, few seed-lot differences, and no provenance differences in seedlings 4 and 16 months of age. In contrast, accelerated seedlings exhibited pronounced seed-lot and provenance differences at both ages and had a 29 and 80% height superiority at 4 and 16 months, respectively. Provenance differences in height, budbreak, nodes, and growth flushes revealed by the accelerated treatment and supplemented by seed characteristics indicate existence of Upper and Lower Peninsula races in Michigan. Accelerated growth techniques may have considerable potential for reducing the time required for genotypic evaluation of sugar maple and possibly other tree species, but results must be substantiated by subsequent field observations.
Understory biomass and nutrients 2 years after timber harvest in northern Minnesota
Authors: Outcalt Kenneth W. , White Edwin H.
Published: July 2007

Adjacent areas within a 60-year-old Abiesbalsamea (L.) Mill. – Betulapapyrifera Marsh, stand in northern Minnesota, U.S.A., were clear-cut by whole-tree logging or tree-length logging followed by prescribed burning. Two years after harvest, understory biomass and nutrients were sampled on these sites and on an adjoining uncut control. All logged sites had significantly more total aboveground understory biomass than the control. However, biomass of woody species on the tree-length logged burn area did not differ from the control site. Because of the greater biomass on harvested sites, nutrient accumulations (N, P, K, Ca, Mg) by the understory were greater, with about 75% of these extra nutrients in herbs and shrubs. Although the quantity of nutrients in the understory is less than that removed with the overstory, it is important in maintaining the nutritional integrity of the system because it serves as a sink for available nutrients.
Influence of postseverance treatments on the rooting capacity of Fraser fir stem cuttings
Authors: Hinesley L. E. , Blazich F. A.
Published: July 2007

Postseverance treatments of wounding, auxin, disbudding, bottom heat, and chilling were examined for their effects on rooting stem cuttings (tips of primary axes) of young Fraser fir (Abiesfraseri (Pursh) Poir.) stock plants. Applied auxin consistently increased rooting percentages and the number and length of roots. Wounding alone did not affect the rooting response, but was beneficial in combination with applied auxin. Certain wounding treatments were better than others. Roots rarely emerged from wound margins and were usually observed at the base of cuttings. Bottom heat enhanced rooting, particularly in combination with wounding + auxin. Removal of lateral buds had a negligible effect on rooting. Following 4 and 8 weeks of artificial chilling, cuttings initially taken in early November rooted well if treated with wounding + indolebutyric acid. However, terminal budbreak was more complete following an 8-week chill. Cuttings taken in late January rooted well without additional chilling. Less chilling was required for rooting than for budbreak.
A generalized Monte Carlo simulation model for decision risk analysis illustrated with a Dutch elm disease control example
Authors: Betters David R. , Schaefer James C.
Published: July 2007

Decision making is often performed under conditions of uncertainty and risk. A Monte Carlo simulation model is described which can help analyze alternatives where these conditions exist. The simulation model has a generalized format so that it may be easily applied to a number of different situations. The basic structure of the simulation model is discussed, and then the model is applied to a problem involving two Dutch elm disease (DED) control strategies. The simulation results, including probability density functions and cumulative distribution functions, are described.
Early genetic evaluation of loblolly pine
Authors: Waxler Michael S. , Buijtenen J. P. van
Published: July 2007

Seedlings of five known fast-growing, open-pollinated loblolly pine (Pinustaeda L.) families and five known slow-growing families were grown from seed to 24 weeks of age in a greenhouse. Each family was subjected to four moisture regimes ranging from high stress levels to little or no stress. Various seedling growth parameters were measured and evaluated to determine their value as predictors of field performance of the same families tested over a range of site conditions. Results showed that the shoot weights and shoot/root ratios of known fast-growing families were significantly greater than those of known slow-growing families at the seedling stage of development. The average shoot/root ratio per family of seedlings grown under unstressed and mildly stressed conditions showed significant positive correlations (r = 0.74 and r = 0.61 respectively) with the average volume superiority of the same families field-tested over a range of sites. (Volume superiority = (volume of family/average volume of plantation) × 100.) The average shoot weight per family of seedlings grown under mild and moderate moisture-stress conditons were also significantly correlated (r = 0.65 and r = 0.66 respectively) with average volume superiority. Shoot/root ratio of seedlings grown under the unstressed water regime was the best overall predictor of later field performance.
Identification, abundance, and origin of moss, liverwort, and algal contaminants in greenhouses of containerized forest nurseries
Authors: Ross Richard L. M. , Puritch George S.
Published: July 2007

Five containerized forest nurseries in British Columbia were surveyed for cryptogam (moss, liverwort, and algal) contamination. Fourteen cryptogam species (five bryophyte and nine algal species) were identified from contaminated styroblock containers. No cryptogams were cultured from the peat and soil mix samples and no mosses or liverworts were detected in the water samples. Algae were found in water samples of two of the five nurseries, but only one of these had species similar to those contaminating the styroblocks. Air samples contained moss, liverwort, and six of the nine algal contaminant species. The relative abundance and distribution of cryptogams at each nursery is given and data are presented which indicate an airborne mode of contamination. The results are discussed with respect to the nature of the contamination and possible control of cryptogam pests in greenhouses of containerized forest nurseries.
A dynamic programming analysis of silvicultural alternatives for red pine plantations in Wisconsin
Authors: Martin George L. , Ek Alan R.
Published: July 2007

An individual tree based stand growth model was analyzed, via dynamic programming, for thinning and final harvest strategies leading to maximum physical yields. Optimal density yield tables, indicating maximum yields and corresponding strategies, were constructed from the solution of the dynamic programming networks. Maximum yields averaged 25 – 30% higher than comparable yields reported previously for periodically thinned red pine plantations.
Reducing conelet abortion in longleaf pine with chemicals
Authors: Hare Robert C.
Published: July 2007

Premature shedding of a large percentage of the conelets in longleaf pine (Pinuspalustris Mill.) substantially reduces orchard seed yields. Spraying conelets and bearing branches with antiethylene compounds and cytokinins once in early May increased conelet survival. In combination with boric acid, the treatment was especially effective. Silver nitrate was ineffective.
The role of Douglas-fir stem sapwood and heartwood in the mechanical and physiological support of crowns and development of stem form
Authors: Long James N. , Smith Frederick W. , Scott David R. M.
Published: July 2007

The mechanical and physiological support of a tree's crown is the principal function of its bole. A simple model for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) of different crown classes explains much of the observed differences in stem form development. Sapwood cross-sectional area at any height on the bole of the tree was found to be related linearly to the amount of foliage above that point; however, in large trees the sapwood area needed to supply transpiring foliage with water is insufficient to provide mechanical support. The combination of sapwood and heartwood was found to provide the stem form that would be expected to ensure uniform resistance to bending by the wind.
Seed and cone production in a clonal orchard of jack pine (Pinusbanksiana)
Authors: Todhunter Michael N. , Polk R. Brooks
Published: July 2007

Seed and cone production in Pinusbanksiana Lamb. was studied using clonal material. Variables studied included sound seed per cone, sound seed percentage, seed efficiency, total seed per cone, seed potential, and total number of cones in relation to site, clone, and position in the crown. The clonal effect was highly significant for all variables. Site and crown location were significant for all but seed total and number of cones. Due to the variability present, cone and seed production should be taken into account in seed orchard design, tree selection, and breeding.
Germination of red alder (Alnusrubra) seed from several locations in its natural range
Authors: Elliott D. M. , Taylor I. E. P.
Published: July 2007

Germination tests were carried out on stratified, presoaked, and untreated seeds of red alder (Alnusrubra Bong.) collected from several locations throughout its range. Dormancy was not a significant factor in preventing germination of untreated seeds with one exception. Germination of untreated seeds, except those from the provenance showing dormancy, and of treated seeds of all provenances was relatively high and showed few differences between provenances. There were more pronounced differences in seed vigour, as measured by germination value.
Deterioration of trembling aspen clones in the Great Lakes region
Authors: Shields Jr. W. J. , Bockheim J. G.
Published: July 2007

In order to test the hypothesis that the deterioration of trembling aspen (Populustremuloides Michx.) is related to variations in climate, soil properties, and genotype, 59 trembling aspen clones were sampled in Michigan, Wisconsin, Minnesota, and Ontario. A longevity index (LI) was calculated by taking the difference between predicted basal area from normal yield tables and measured basal area for each clone. Correlations of environmental variables with LI indicate that aspen longevity decreases with increasing mean annual temperature. Under similar temperature regimes, aspen growing on xeric sites and on sites low in exchangeable Ca are most susceptible to early breakup. Since there were negligible differences in soil properties between nine pairs of adjacent deteriorating and relatively well stocked clones, we hypothesize that, under similar environmental conditions, variation in the timing of deterioration may be due to genotypic differences between clones.
Groove formation in the stem of red pine associated with branches
Authors: Fayle D. C. F.
Published: July 2007

Annual changes in the radial and longitudinal extent of grooves above and below branches on the stem of a 40-year-old red pine (Pinusresinosa Ait.) were determined by examination and measurement of annual rings on cross sections. Grooves appeared above branches when they were in the fourth whorl and maximum vertical extent occurred about the time of branch death. Ring widths within grooves compared with those between grooves decreased slowly at first, then more rapidly, reached a minimum the year after branch death, and then increased. Below branches, groove initiation was later, far less extensive, and minimal within-groove compared with between-groove ring widths occurred the year of branch death. The course of groove development appeared to be associated with the changing vigor of branches and with the nature of the junction between stem and branch. It is suggested that groove development above branches in red pine is the result of localized water deficiency, whereas groove development below branches is related to reduction in photosynthate availability.
Four-year height growth variation among and within S0, S1 × S1, S1 open-pollinated, and S2 inbred jack pine families
Authors: Rudolph Thomas D.
Published: July 2007

After 4 years, inbreeding depression in tree height of jack pine (Pinusbanksiana Lamb.) was from 18 to 24% in S2 (second selfed generation) progenies compared with S0 (original female parents) open-pollinated progenies. This indicates a high degree of dominance for height growth. Crosses between S1 (first selfed generation) lines and open-pollinated progenies from S1 trees showed heterosis and relief from inbreeding depression so that vigor was restored to at least the level of the ancestral S0 parents. Genetic variance among S2 progenies was greatly increased indicating that inbreeding increased heritability of height growth.
Survival and growth of understory trees in oak forests of the Hudson Highlands, New York
Authors: Lorimer Craig G.
Published: July 2007

Mortality and growth rates of trees in various crown classes and size classes were analyzed from 40-year permanent plot records of slope and ravine forest dominated by chestnut oak (Quercusprinus L.) and northern red oak (Quercusrubra L.). Average 5-year mortality rates for suppressed trees ≥2.5 cm dbh of chestnut oak and red oak in the slope forest were 26 and 45%, respectively. None of the suppressed red oaks survived the 40-year period, compared with 14% of the chestnut oaks and 33% of the red maples (Acerrubrum L.). Mortality of oak trees in the intermediate crown class was less than half that of suppressed trees, but still much higher than that of maples and birches on the tracts. Survival was reasonably high for oaks as long as the top of the crown was receiving direct sunlight, but the expected 40-year survival rate of red oaks in such a position is only 20%, with an average growth rate of 1.0 mm in diameter per year. Curves and equations expressing average mortality and growth rates at various levels of competition are presented for each species.
Effects of controlled-release fertilizers on shoot and root development of outplanted western hemlock (Tsugaheterophylla Raf. Sarg.) seedlings
Authors: Carlson William C.
Published: July 2007

Controlled-release fertilizers applied to the root zone of 1-0 plug western hemlock (Tsugaheterophylla Raf. Sarg.) at planting stimulated shoot and root growth in the following two growing seasons. The number and diameter of lateral roots was increased by fertilizing, but fertilizing did not alter the shoot–root ratio. The shoot–root ratio did not increase with an increase in seedling size, height, or total weight.
Comparative toxic effects of some xenobiotics on the germination and early seedling growth of jack pine (Pinusbanksiana Lamb.) and white birch (Betulapapyrifera Marsh.)
Authors: Weinberger Pearl , Vladut Ritta
Published: July 2007

Seeds of jack pine (Pinusbanksiana Lamb.) and white birch (Betulapapyrifera March.) were germinated in homogeneous emulsions or aqueous tank-mix solutions of fenitrothion or Matacil and their respective adjuvants: Atlox and Aerotex, or diluent oil No. 585 and nonylphenol. Percentage and peak germination values, water uptake, sprout length, ATP content, and morphological modifications were recorded from 0 to 14 or 21 days. Apart from 100 ppm fenitrothion which stimulated germination values, germination in jack pine was only marginally affected by any of the treatments; in contrast, white birch was negatively affected by all treatments. The most sensitive parameters of toxicity were the sprout length and ATP content after 14 days growth. Aberrant hypocotyl/root length ratios were evidenced in pine seeds after exposure to xenobiotic treatments which did not affect the germinative capacity of seeds. ATP content in the 14-day-old pine and birch seedlings was consistently higher than controls in all treatment sets.
À propos de l'âge du sapin baumier et de sa détermination
Authors: Zarnovican R.
Published: July 2007

A study of 162 dominant balsam-fir trees was conducted to determine the length of the juvenile growth stage. Results indicated that the length of this stage is less than 10 years in a plot naturally regenerated following clear-cutting, and the effect of this period on tree age disappears when the trees reach a height of 30 cm. However, with adult trees from various sources, this juvenile growth stage can last up to 50 years as well as affect trees of up to 2.4 m in height, and therefore, the age of the tree as determined by dbh. After comparing the growth-time interval with height at time t3 and time t3, the results of this field study suggest that the growth-time interval must be equal or less than 7 years for tree age as determined by dbh to be unaffected by suppression. [Journal translation]
A new method for recording directional traffic on forest roads
Authors: Liu C. J. , Erickson D. L.
Published: July 2007

To properly manage forest land areas, accurate methods for recording directional traffic are needed. A newly developed logic circuit coupled with a longitudinal arrangement of the sensing loops increases the precision of directional traffic counts on one-or two-lane forest roads. The device requires no change in the logic of the original traffic recorder, nor additional service or maintenance. This method can be accommodated to various traffic recording networks and most brands of multichannel traffic recorders.