bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in specific gravity of red alder (Alnusrubra Bong.)
Authors: Harrington Constance A. , DeBell Dean S.
Published: April 2011

Specific gravity of breast-high wood did not vary significantly among ten 9-year-old sources used in an Alnusrubra (Bong.) provenance trial. Correlations between specific gravity and diameter were also nonsignificant. In a study of seven natural stands selected to cover a range of site conditions, specific gravity did not differ among stands and was not correlated with 25-year radius in six of the seven stands. Analyses of three- to five-ring samples from trees selected from the natural stands revealed no consistent relationships between specific gravity and age or distance from the pith. The correlations between specific gravity and ring width or ring area (measured on the three- to five-ring samples) were negative and highly significant; however, the actual values of the correlation coefficients were quite low (r = −0.21, r = −0.20). The authors conclude that individual tree selection for growth rate or silvicultural treatments to increase growth will probably have little influence on specific gravity. The uniform specific gravity of wood from stands of varying ages and different locations is a desirable feature in the wood and fiber industries.
Relationship of sap sugar concentrations in sugar maple to ray tissue and parenchyma flecks caused by Phytobiasetosa
Authors: Wallner William E. , Gregory Robert A.
Published: April 2011

Sap sugar levels were determined for 300 sugar maple, Acersaccharum Marsh, trees. The 10 trees highest and lowest in sap sugar were sacrificed and attempts were made to calculate abundance and size of parenchyma flecks caused by Phytobiasetosa (Loew) and ray tissue per unit of xylem. Flecks occurred in up to 0.2% of the xylem, but there was no significant difference between fleck number or xylem-fleck ratio and sap sugar levels. Fleck numbers decreased with tree height; largest flecks were observed at the root collar and 8–12 m from the ground. This suggests that all P. setosa larvae do not mine from twigs in the crown to the roots, but that some mature and exit at the base of the tree crown. Trees high in sap sugar had significantly more ray tissue per unit of xylem than those low in sap sugar, a major factor in determining sap sugar concentrations.
Seasonal changes in energy allocation by white oak (Quercusalba)
Authors: McLaughlin S. B. , McConathy R. K. , Barnes R. L. , Edwards N. T.
Published: April 2011

Seasonal patterns of change in lipids, sugars, starch, labile (ethanol soluble) constituents, holocellulose, and lignin were studied in six forest-grown white oak (Quercusalba L.) trees. Contents of metabolically active constituents in leaves, twigs, branches, boles (upper and lower), and roots (support and small lateral) were used to construct whole-tree budgets of energy allocation. [14C]Sucrose was also concurrently supplied to the study trees to follow the fate and efficiency of utilization of food reserves. Results showed that white oak rapidly mobilized and replaced food reserves during the critical period of canopy generation in the spring. Starch was more important as a reserve food than lipids or sugar. Large fluctuations in starch in roots in spring and fall suggested a bimodal belowground growth pattern. Labile constituents showed the most pronounced seasonal changes and dominated the calculated whole-tree energy flux patterns. Rapid decline in labile compounds in early spring and a parallel increase in holocellulose suggested a possible pattern of mobilization and resupply of stored reserves associated with in cell wells. This possibility was supported by a concurrent shift of labile 14C to nonlabile 14C in tissues. Canopy generation was calculated to have cost ≤17.7 kg of glucose (1.6 g glucose/g of canopy) of which 13 kg appeared to have come from within the canopy.
The growth of lodgepole pine seedlings raised under clear polythene cloches at five seedbed densities
Authors: Thompson S.
Published: April 2011

The components of shoot growth and dry matter production in 1 + 0 lodgepole pine (Pinuscontorta Dougl. ex Loud. spp. contorta) seedlings raised under clear polythene cloches for 12 weeks at five seedbed densities (180–720 plants/m2) were studied. The greater plant height found at the highest seedbed density was the result of increased stem unit length, not increased number of stem units. The increase in plant dry weight as seedbed density decreased was largely due to greater dry weight of roots, branchwood, and branch foliage, and not to increases in stemwood and stem foliage weight. Seedbed densities of less than 460 seedlings/m2 are required to produce yields of suitably sturdy seedlings in excess of 50% of the crop.
Partial cut harvesting and ectomycorrhizae: early effects in Douglas-fir-larch forests of western Montana
Authors: Harvey A. E. , Larsen M. J. , Jurgensen M. F.
Published: April 2011

Numbers of ectomycorrhizae were assessed 3 years after harvesting approximately 50% of the overstory in two Douglas-fir-larch stands in western Montana, one was subjected to intensive residue removal, the other broadcast burned 1 year after harvest. Numbers of active ectomycorrhizal root tips were significantly reduced in the broadcast burned stand compared to either the intensively utilized stand or to an adjacent, undisturbed stand. This indicates that on difficult-to-regenerate sites, particularly where soil organic matter is low, it may be advantageous to dispose of slash created in partial cuts by means other than burning.
Acclimation of cold-stored jack pine and white spruce seedlings: effect of soil temperature on water relation patterns
Authors: Grossnickle Steven C. , Blake Terence J.
Published: April 2011

Cold-stored jack pine (Pinusbanksiana Lamb.) and white spruce (Piceaglauca (Moench) Voss) seedlings were planted in a controlled environmental chamber providing an air temperature of 22 °C and soil temperatures of 22, 16, or 10 °C. After 21 days, observation of root growth for white spruce seedlings was limited at all soil temperatures, whereas jack pine seedlings showed limited root growth at a soil temperature of 10 °C but not at 22 °C. During 21 days of observation after removal from cold storage, stomatal response patterns changed during the transition phase from darkness to first light. Jack pine seedlings showed increasing stomatal opening at first light with greater stomatal opening for seedlings in the 22 °C root-temperature treatment, while all white spruce seedlings exhibited a greater stomatal closure during darkness. In both species, seedlings at lower soil temperatures experienced greater initial water stress than seedlings at higher soil temperatures, the difference being associated with a greater water-flow resistance through the soil–plant–atmosphere continuum (SPAC). In both species, xylem pressure potentials increased with time at all temperatures; a change attributable to a decline in water-flow resistance through the SPAC. The decline in water-flow resistance was possibly due to either a change in the permeability of older suberized roots or, as in jack pine at the higher soil temperature, a significantly greater development of new unsuberized white roots.
Vegetation relationships among some seral ecosystems in southwestern British Columbia
Authors: Klinka K. , Scagel A. M. , Courtin P. J.
Published: April 2011

A new classification scheme is proposed for managed second-growth forests, which is based upon ecologically equivalent sites rather than purely floristic or structural characteristics of vegetation. For demonstration purposes, six structural (developmental) stages were sampled and classified. The seral stages, listed in increasing age after harvesting are as follows: initial, regeneration, early immature, late immature, mature, and old growth. The results of numerical and tabular analyses suggested the presence of two major floristic groups (seral associations) of the above seral stages: (i) Epilobium – Polytrichum (initial and regeneration seral stages) and (ii) Pseudotsuga – Hylocomium (early immature to old growth seral stages). The Epilobium – Polytrichum seral association was found to represent seral vegetation of regeneration stages on four different site types, all of which are common in southwestern British Columbia.
Performance of Anthocephaluschinensis in Puerto Rico
Authors: Lugo Ariel E. , Figueroa Julio
Published: April 2011

The growth of kadam (Anthocephaluschinensis (Lam.) A. Rich. ex Walp.), a fast-growing Asiatic species, was studied under different soil and climatic conditions in Puerto Rico. Plantings included a 10-year-old line planting, a 12.5-year-old plantation, 12 localities with 20-year-old single tree plots, and 1 locality with four 52-year-old trees. Over 600 trees were measured in all. Growth rates were comparable to those of fast-growing species elsewhere in the tropics; e.g., the 12.5-year-old plantation had a volume growth of 27.8 m3•ha−1•year−1 (77% was merchantable wood), a basal area growth of 1.82 m2•ha−1•year−1, and a total aboveground biomass production of 11.5 t•ha−1•year−1. Trees grew well both in plantations and in lines under natural forest. The 20-year-old single tree plots averaged up to 1 m•year−1 in height growth and 53 cm2•year−1 in basal area growth. Highest rates were observed in localities with high annual rainfall (>2500 mm) and with phosphorus- and silt-rich soils of high bulk density and low pH. After 10 years, basal area growth of trees was fastest in volcanic deep clay locations, followed, in order, by trees on volcanic shallow loams, calcareous soils, and plutonic sandy loams. However, basal area growth during the first 5 years was fastest in the plutonic sandy loams and slowest in the calcareous soils. After 20 years, volcanic deep clay soils still supported the fastest basal area growth rate (about 100 cm2•year−1), while the other locations converged at about 30 cm2•year−1. Trees reached maximum height after 20 years (average, 19 m; maximum, 26.5 m). Kadam growth was limited by close spacings (below 2.5 × 2.5 m). Trees exhibited excellent form (ratio of diameter at 1.3 m to diameter at 4.9 m > 0.8). We found no evidence of pest or disease attacks on trees, but noted severe tapering and stem twist in localities having poor growth rates. Results underline the need for caution when making species adaptability assessments in the tropics with short-term (<10 years) data.
Heritability estimates for height for young interior spruce in British Columbia
Authors: Kiss G. , Yeh F.C.
Published: April 2011

Height growth for interior spruce (Piceaglauca (Moench) Voss and P. engelmannii Parry) after 3, 6, and 10 growing seasons was assessed in a progeny test of 174 wind-pollinated families at three test sites in north central British Columbia. Test sites had a major influence on the juvenile growth of interior spruce, reflecting differences in potential site productivity as well as the importance of good site preparation and subsequent brush control for spruce seedlings. Mean heights within and across sites differed among families. The 3- and 6-year family performances correlated with family performances at age 10. Family–site interaction was significant at the 1% probability level, but accounted for no more than a quarter of the family variance at the three assessment years. Performance of the top and bottom 25% of families was consistent across the three sites. The narrow-sense heritability estimates after the third, sixth, and tenth growing seasons were 0.52, 0.36, and 0.29, respectively. The corresponding family heritability estimates were 0.82, 0.73, and 0.67, respectively.
Red spruce stands downwind from a coal-burning power generator: tree-ring analysis
Authors: Arp Paul A. , Manasc Justin
Published: April 2011

Tree rings of red spruce (Picearubens Sarg.) in uneven-aged forest stands downwind of an SO2, source (a coal-burning power generator) were analyzed in terms of spatial and temporal trends for bole increments and elemental concentrations (Al, Ca, Mg, K, P, Mn, Zn, Fe, Ni, Cu, Cr) in xylem. Five-year core segments were pooled with respect to distance from emission source, time of wood formation, and tree age (young trees <35 years; old trees >35 years). Soil analysis was done for all stands (total of 28) by soil layer (forest floor, A and B horizons) for pH, exchangeable K, Ca, Mg, Al, and oxalate-extractable Al and Fe. Also analyzed was the snowpack at each stand at three sampling dates in February and March 1986. The snow data for pH, Ca, Mg, K, and SO4 were highly variable, with some of the variability presumably related to fallout of fly ash. The soil data were also variable, but revealed a gain of water-soluble and bicarbonate-extractable SO4, and a loss of exchangeable Mg with increasing proximity to the power generator. Magnesium levels in the wood of the red spruce trees showed a similar trend. Wood concentrations for Ca, Mg, Mn, and Zn were found to decrease with increasing stand age. In contrast, wood concentrations for P, K, Fe, Ni, Cu, and Cr were highest in the most recently formed xylem. Some of these variations were probably affected (i) by the affinity of the wood for each element during wood formation, and (ii) by removal through flow of xylem sap. Some of these trends may also reflect changed ion availabilities in the soil or may be due to air pollution. Trends for the age-related variations of mean bole increments in each of the uneven-aged stands were probably affected by within-stand competition, modified by selective logging, and by recurring outbreaks of spruce budworm (Choristoneurafumiferana Clem.). An enhanced rate of SO2 emission since about 1965 may also have had a negative effect on radial bole growth. The availability of soil water appeared to be a principal factor in relating a tree growth index to year by year climate variations. This tree growth index (developed for an even-aged stand of red spruce upwind from the power generator) was positively related to precipitation of the preceding year and to precipitation in July and August (time of latewood formation). The growth index was negatively related to prolonged periods of high temperatures during earlywood formation.
Promotion of aerenchyma formation in Pinusserotina seedlings by ethylene
Authors: Topa M.A. , McLeod K.W.
Published: April 2011

The following study was designed to investigate a possible regulatory role for ethylene in aerenchyma and lenticel formation in pond pine (Pinusserotina Michx.) seedlings, a moderately flood-tolerant species. Seedlings were grown in noncirculating, continuously flowing solution culture under aerobic or hypoxic solution conditions; half the seedlings were treated with exogenous ethylene for the last 23 days of the 30-day treatment period. Ethylene stunted root growth, induced hypertrophy of stems and taproots, and initiated adventitious root and lenticel formation in aerobically grown seedlings. Histological studies indicated that taproot hypertrophy and resultant fissures were partially due to both an increase in number and radial enlargement of loosely packed parenchyma cells in the pericycle region. Exogenous ethylene also promoted the predominantly schizogenous formation of intercellular air spaces in the pericycle region of aerobically grown seedlings, enough to allow longitudinal diffusion of atmospheric O2 to submerged roots, as indicated via an indigo-carmine dye technique. Ethylene-treated seedlings grown under hypoxic conditions exhibited signs of reduced root vigour, with more pronounced taproot hypertrophy and fissuring than in the aerobic + ethylene treatment. Taproot fissures were a result of a proliferation of undifferentiated, loosely packed parenchyma cells in the pericycle region, with little continuous periderm development or evidence of a well-defined phellogen. Our results suggest that ethylene promotes those morphological changes in flooded roots that increase internal porosity, enhancing internal aeration.
Throughfall chemistry beneath Quercusrubra: atmospheric, foliar, and soil chemistry considerations
Authors: Leininger T. D. , Winner W. E.
Published: April 2011

Concentrations of inorganic ions were measured in bulk rainfall and bulk throughfall collected beneath northern red oak (Quercusrubra L.) trees growing in fertile, limestone-derived soil and less fertile sandstone/shale-derived soil. Rainfall passing through the crowns at both sites was enriched with [Formula: see text], [Formula: see text], Ca2+, Mg2+, K+, Mn2+, and Fe2+, but lost [Formula: see text] to the crowns. Concentrations of Na+ and H+ in incident rainfall were higher at the infertile site. There was no difference in ionic leaching from red oak crown leaves exposed to simulated acid rain solutions. Rainfall volume, leaf area, and large particle dryfall ionic concentrations were all larger at the fertile rather than the infertile site. Concentrations of Ca +, Mg2+, [Formula: see text], Mn2+, and [Formula: see text] measured in throughfall at the fertile site were higher than those of the infertile site. These differences in throughfall chemistry are likely due to site differences in (i) the ability of tree crowns to capture dry deposition, (ii) dry deposition chemistry and occurrence, and (iii) rainfall volume.
Spruce budworm defoliation and growth loss in young balsam fir: defoliation in spaced and unspaced stands and individual tree survival
Authors: Piene Harald
Published: April 2011

A severe outbreak of spruce budworm (Choristoneurafumiferana (Clem.)) began in 1976 in young, spaced and unspaced stands of balsam fir (Abiesbalsamea (L.) Mill.) located on the Cape Breton Highlands, Nova Scotia, Canada. A study was initiated that year to relate decreases in foliar biomass, caused by defoliation, to reductions in annual volume increment. Detailed defoliation assessments on individual trees from 1976 to 1984 showed severe defoliation of the current foliage in 1976. In 1977 and 1978, current foliage was destroyed in the early part of shoot elongation and severe back-feeding occurred on older age-class needles. After 1978, defoliation decreased as a result of a decline in budworm populations and, in general, only the current foliage was defoliated until the populations decreased to low levels in 1983. Defoliation was significantly higher in spaced than in unspaced stands in 1977, 1978, and 1980, and as a result, by 1984, average tree mortality caused by spruce budworm was 43.8% in spaced and 18.9%.in unspaced stands. The survival of some balsam fir trees and not others following a budworm outbreak is not related to differential defoliation, but to the ability of some balsam fir trees to rapidly increase foliar biomass through prolific epicormic shoot growth.
Optimal harvest of a forest in the presence of uncertainty
Authors: Gassmann Horand I.
Published: April 2011

A method is described for finding logging levels to maximize harvest in a finite horizon type II model. Uncertainty is considered in the form of the risk of forest fires and other environmental hazards, which may destroy a random fraction of the existing forest. Numerical results include upper and lower bound approximations to the original problem.
The role of autoxidation of α-pinene in the production of pheromones of Dendroctonusponderosae (Coleoptera: Scolytidae)
Authors: Hunt D. W. A. , Borden J. H. , Lindgren B. S. , Gries G.
Published: April 2011

The monoterpene α-pinene, a major component of the terpene composition of Pinus spp., has been reported to act as a host-produced kairomone for a variety of bark beetle species, including the mountain pine beetle, Dendroctonusponderosae Hopkins. However, our experiments indicate that α-pinene autoxidizes under normal temperature and atmospheric conditions to form significant quantities of trans-verbenol, an aggregation pheromone for many species of bark beetles. The quantities of α-pinene present in the resin that can flow from small wounds in pine trees appear to be sufficient to produce trans-verbenol at rates similar to those by female beetles that are actively synthesizing the compound.trans-Verbenol can then autoxidize rapidly to form verbenone, with the content of this compound reaching 8% within 13 weeks of exposure to air. Verbenone is often used by scolytids as an antiaggregation pheromone. Approximately 1.9% of the trans-verbenol and 2.7% of the verbenone found in Porapak Q aerations of phloem with boring spruce beetle, Dendroctonusrufipennis (Kirby), females, as well as 0.8% of the trans-verbenol and 0.8% of the verbenone found in aerations of phloem with boring D. ponderosae females, was due to the autoxidation of α-pinene and (or) the release of oxygenated compounds found in the phloem before bark beetle attack. The natural interconversion of α-pinene, trans-verbenol, and verbenone under ambient conditions suggests that many experiments involving the behavioral activity of these compounds require re-evaluation.
Effect of straw residues on black spruce seedling growth and mineral nutrition, under greenhouse conditions
Authors: Jobidon Robert , Thibault J. Robert , Fortin J. André
Published: April 2011

The potential allelopathic (phytotoxic or beneficial) effect of barley, oat, and wheat straw mulches was evaluated on growth, mineral nutrition, and mycorrhizal status of black spruce seedlings, under greenhouse conditions. The various straws did not affect spruce seedling height growth over a 2-month growth period. The newly formed fine roots of treated and control seedlings were mycorrhizal. Oat and wheat straw significantly enhanced foliar phosphorus content, as compared with the control. All treatments significantly depressed foliar manganese content, indicating that the straws could exert a detrimental effect on manganese uptake. Therefore, it is suggested that monitoring the status of manganese in planted spruce seedlings when using allelopathic cover straw mulches be used as a method for preventing the establishment of weed species.
Rooting micropropagated shoots from mature radiata pine
Authors: Horgan Kathryn , Holland Lyn
Published: April 2011

A reliable method of rooting shoots from mature micropropagated Pinusradiata D. Don has been developed. At the beginning of the research, difficulty in achieving consistent results was experienced. At the end of the series of described experiments, high rooting percentages (78%) were attained. The condition of shoots is important. Shoots that had been cold-stored prior to rooting did not survive. Best rooting was obtained in a free-draining peat–pumice–perlite medium in propagation trays maintained under controlled environmental conditions. A well-managed watering regime and the gradual conditioning of shoots from the day of setting enhanced survival and rooting. Removal of basal callus from shoots prior to an auxin treatment significantly improved survival (30–70%) and rooting (16–56%). A further improvement was made by providing a 5 week prerooting treatment of nutrient medium containing 6% sucrose. This pretreatment was particularly effective for one difficult to root clone. Shoots formed vigorous plantlets which were successfully acclimatised to full sunlight within 4–6 weeks of transfer to root trainers. Plantlet survival ranged from 90 to 100%.
Forty years of alternative management practices in second-growth, pole-size northern hardwoods» IL Economic evaluation
Authors: Niese Jeffrey N. , Strong Terry F. , Erdmann Gayne G.
Published: April 2011

Potential economic returns to tree quality were analyzed for four uneven-aged cutting treatments and a control in a Wisconsin northern hardwood stand. The economics of tree quality changes were analyzed over a 20-year period (1971–1992), using a marginal analysis that included tree grade, lumber volume yields, reported lumber values, and hardwood management costs. Net present values were highest for the heavy individual tree selection (60 ft"/acre, 13.8 m2/ha) treatment, and residual tree quality improved significantly. The medium selection (75 ft2/acre, 17.3 m2/ha) treatment had the greatest improvement in tree quality as well as high economic returns. The light selection (90 ft2/acre, 20.7 m2/ha) treatment had the highest residual stand value, but low harvest revenues. An 8-in. (20.3-cm) diameter-limit treatment had the lowest economic returns and the poorest tree quality.
Association of within-tree jack pine budworm feeding patterns with canopy level and within-needle variation of water, nutrient, and monoterpene concentrations
Authors: Wallin Kimberly F , Raffa Kenneth F
Published: April 2011

The possibility that uneven within-tree feeding patterns by jack pine budworm (Choristoneura pinus pinus Freeman) larvae could be related to underlying variation in host jack pine (Pinus banksiana Lamb.) foliar water, nutrient, and monoterpene contents was considered. Choristoneura pinus pinus feeds disproportionately in the upper portion of the canopy and almost exclusively on the basal portions of needles. Within needles, the distribution of water, several nutrients, and monoterpenes varied significantly between the distal and basal sections. Water, nitrogen, sulfur, manganese, and zinc levels occurred in higher concentrations in the distal section of the needle, which would not be predicted based on C. pinus pinus feeding patterns. Phosphorus, potassium, calcium, iron, and copper were significantly higher in the basal section. Although the latter differences might be predicted based on C. pinus pinus feeding patterns, they were not strong (ranging from 7.8% to 36.4% relative differences, as compared with 10.7%-50.0% relative differences in the former group). By contrast, concentrations of foliar monoterpenes were more strongly associated with known feeding patterns of C. pinus pinus. These relative differences ranged from myrcene (26.8%) to limonene (44.79%). Thus, foliar differences affecting within-needle feeding selection appear more associated with allelochemicals than nutrients or water. In contrast with the within-needle associations between larval feeding and foliar chemistry, no associations between upper and lower canopy foliage were observed. Water, nutrients, and monoterpenes were evenly distributed across the upper and lower canopy locations. Thus, differential feeding between canopy locations cannot be explained by foliar constituents. Rather, it is more likely explained by other environmental factors, such as proximity to and density of reproductive and vegetative shoots.
Influence de quelques défauts externes sur la stabilité des arbres face à une simulation mécanique de l'action du vent
Authors: Silva G , Ruel J -C , Samson M , Pin D
Published: April 2011

A simulation of wind action was achieved to test the influence of some external defects on the resistance of standing trees of balsam fir (Abies balsamea (L.) Mill.), yellow birch (Betula alleghaniensis Britton), and trembling aspen (Populus tremuloides Michx.). The methodology used consisted of applying a force on the tree with a winch. Every tree was filmed during winching, and the geometrically corrected images were used to compute displacement. Balsam fir trees tended to break more than uproot, and in most cases, breakage occurred at the crack level. Even though maximum turning moment did not differ between control and defective balsam fir trees, a significant difference was found for maximum stress, showing a reduction in resistance associated with cracks. No reduction in resistance could be seen for the other species, but trees were relatively young and care should be taken before extending these results to older trees.
Growth rate effects on correlations among ring width, wood density, and mean tracheid length in Norway spruce (Picea abies)
Authors: Dutilleul Pierre , Herman Marc , Avella-Shaw Tomas
Published: April 2011

The main hypothesis tested in this paper is whether heavy thinnings affect the correlations among ring width, wood density, and mean tracheid length. Within-tree correlations were calculated between time series of yearly measurements. Among-tree correlations were computed (1) between averages over a growing period and (2) year by year. Correlations were analyzed on 20 fast-grown and 20 slow-grown Norway spruces (Picea abies (L.) Karst.) from an even-aged, plantation-grown stand near Rendeux, Belgian Ardennes. In the within-tree approach, fast-grown spruces showed a stronger negative correlation between ring width and fiber length. In among-tree approach 1, the widely held negative correlation between ring width and wood density vanished when the spruce growth rate was above 2.2 cm/year in circumference. Among-tree approach 2 demonstrated that the magnitude and sign of the correlations also depended on the year; a few years showed a significant correlation between ring width and wood density for the fast-grown Norway spruces, whereas the correlation was systematically negative and significant on many years for the slow-grown spruces. This study may explain part of the contradictory results reported in the literature concerning hypotheses similar to ours.
Effects of excess nitrogen deposition and soil acidification on sugar maple (Acer saccharum) in Ontario, Canada: an experimental study
Authors: Hutchinson Thomas C , Watmough Shaun A , Sager Eric PS , Karagatzides Jim D
Published: April 2011

The impact of an acidifying fertilizer on litter decomposition, root mycorrhizae, and soil and tree chemistry was assessed in two hardwood forests in central Ontario, Canada. Soil beneath mature sugar maple (Acer saccharum Marsh.) trees was treated with (NH4)2SO4 granules at application rates of 0, 250, 500, and 1000 kg/ha in May of each year between 1993 and 1994 at Dorset and between 1993 and 1995 at Loring. The fertilizer treatments did not cause visual symptoms of forest decline. At Dorset, SO4 and cation concentrations in soil leachate increased, but no difference in soil pH between treatments was found. An increase in foliar N was recorded at Dorset in treated plots, although there were no other differences in foliar or tree ring chemistry between treatments. At Loring, a decrease in soil pH and an increase in SO4 in soil leachate were found in treated plots. Mycorrhizal infection and litter decomposition were also reduced in plots treated with (NH4)2SO4. Fertilizer application at Loring led to increases in foliar concentrations of N, Mg, Mn, and Cd, along with increases in concentrations of trace metals (As, Co, Cr, Mn, Ni, and Zn) in tree rings formed during fertilizer application. Significant positive correlations (p < 0.05) were found between wood (rings formed between 1993 and 1995) and foliage (mean of 1993-1995 values) for Mg, Mn, and Al. Deliberate acidification of surface soil resulted in changes in wood and foliar chemistry, although it remains to be established whether acidification of surface soil is responsible for the reported decline in sugar maple.
Exponential fertilization increases nutrient uptake and ectomycorrhizal development of black spruce seedlings
Authors: Quoreshi A M , Timmer V R
Published: April 2011

Intensive fertilization may inhibit adequate mycorrhizal development for forest nursery stock production. Containerized black spruce (Picea mariana (Mill.) BSP) seedlings exposed to four fertilization regimes (one conventional and three exponential at 12.5, 12.5, 25, and 50 mg N/seedling, respectively) and two ectomycorrhizal inoculations (Hebeloma crustuliniforme (Bull. ex St-Amans) Quel. and Laccaria bicolor (R. Mre.) Orton) were grown from seed to assess mycorrhizal formation and nutrition of young trees under intensive greenhouse culture. Exponentially increasing fertilizer additions stimulated ectomycorrhizal development (49-85%) compared with conventional constant-rate fertilization (22-26%). Exponential fertilization also increased seedling N (13-34%) and P (5-18%) uptake, although dry matter production was reduced (17-25%) at the lowest exponential addition rate. Ectomycorrhizal inoculation did not affect seedling biomass but increased uptake of N (6-17%), P (5-20%), and K (4-18%), demonstrating a potential for nutrient loading by fungi. Higher ectomycorrhizal formation found under exponential fertilization regimes was attributed to lower initial nutrient levels maintained in the growing media. Results indicate that high exponential fertilization combined with fungal inoculation may be effective for producing both nutrient-loaded and ectomycorrhizally infected planting stock.
Effects of clear-cutting, thinning, and wood moisture content on the susceptibility of Norway spruce stumps to Heterobasidion annosum
Authors: Bendz-Hellgren Malin , Stenlid Jan
Published: April 2011

The effects of clear-cutting and thinning as well as heartwood and sapwood moisture content on spore infection by Heterobasidion annosum (Fr.) Bref. were investigated in summer cuttings in southern and central Sweden. At five sites, 20-100 stumps in clear-cut, thinned, and precommercially thinned stands of Norway spruce (Picea abies (L.) Karst.) were created and left for natural spore infection. An additional 20 stumps per stump type and site were artificially inoculated with conidiospores of H. annosum. The probability of natural infection was 0.73 and 0.53 for stumps in thinned and clear-cut stands, respectively. Almost all (95%) of the artificially inoculated stumps in thinned and clear-cut stands became colonized, and no differences due to stump type were found. The probability of infection of stumps in precommercially thinned stands was lower than for the other stump types of both naturally and artificially inoculated stumps. The proportion of colonized sapwood was reduced with increasing moisture content. Stump colonization seemed unaffected by temperature, even though stump temperatures exceeded 40°C for 2 h at one site.
Incomplete block designs for genetic testing: statistical efficiencies of estimating family means
Authors: Fu Yong-Bi , Clarke G Peter Y. , Namkoong Gene , Yanchuk Alvin D
Published: April 2011

A half-sib progeny trial with single-tree plots on one test site of various environmental variations is simulated to examine the relative statistical efficiencies of randomized incomplete block designs (ICBs) over their corresponding randomized complete block design (RCB) in estimating family means. The ICBs with full constraint (FC), half constraint (HC), and no constraint (NC) over replicates and an alpha design (Alpha) are considered. A geostatistical spatial model is employed, which allows specifications of patchy and systematic environmental variations across the test site and estimations of block and error components with SAS PROC MIXED. The simulation shows that Alpha is the most efficient ICB in the 21 scenarios of patchy and systematic site variations, followed by NC and HC, and these ICBs (except FC) are generally more efficient than RCB in terms of the average variance of a family mean contrast. The gains in statistical efficiencies with implementations of Alpha and NC (rather than RCB) in forest genetic testing can be high, depending largely on the nature (and level) of spatial environmental variation. Practical implications of these simulated results for forest genetic trials are discussed.
Ethanol in Douglas-fir with black-stain root disease (Leptographium wageneri)
Authors: Kelsey Rick G , Joseph Gladwin
Published: April 2011

Diseased and healthy Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were identified at two black-stain root disease centers, caused by Leptographium wageneri var. pseudotsugae Harrington & Cobb, in the Oregon Coast Range near Coos Bay. Phloem and sapwood near the root collar were sampled monthly for 1 year, whereas roots were sampled in October and November. Ethanol concentrations in sapwood of diseased trees near the root collar were 4-24 times higher than in healthy trees for all months of a year, except January and June. Roots from diseased trees in October had 5 times more ethanol in the phloem and 19 times more ethanol in the sapwood than corresponding tissue from healthy trees. Ethanol concentrations in roots from diseased trees in November were no different from October. Within trees, ethanol concentrations varied substantially among positions around the root collar and among different roots. Ethanol may play an important role in the biology of L.wageneri and beetle-pathogen interactions in Douglas-fir. Ethanol also may be useful in detecting stressed or diseased trees.
Interactive effects of acidic deposition, drought, and insect attack on oak populations in the midwestern United States
Authors: LeBlanc David C
Published: April 2011

The objective of this study was to determine if acidic deposition predisposes oaks to decline after drought. Associations were evaluated between oak decline and mortality after drought and (1)pre-drought growth; (2)tree size, age, and competitive status; (3)attack by twolined chestnut borer (TLCB); (4)acidic deposition; and (5)soil acidity. This study was conducted in the Ohio River region of the United States. White oak (Quercus albaL.), black oak (Quercus velutina Lam.), and the locally dominant oak (chestnut oak (Quercus prinusL.) or post oak (Quercus stellata Wangenh.)) were studied at six similar sites along an acidic deposition gradient during the period 1988-1992. Prevalence of severe branch dieback and mortality was low ( < 10%) at all sites, but fewer oaks in Illinois were in the 0-10% dieback class than in other states. Also, fewer oaks in Illinois than Ohio exhibited immediate recovery after the 1988 drought. Prevalence of TLCB attack was similar across all sites; >85% of dead trees had been attacked, but <10% of living trees were damaged. Most dead oaks had lower pre-drought radial growth than survivors of the same species. Branch dieback, growth decline, and mortality were more prevalent in the black oak population than the other oak species. There was no evidence that acidic deposition predisposed oaks to post-drought decline.
Genetic diversity in longleaf pine (Pinus palustris): influence of historical and prehistorical events
Authors: Schmidtling R C , Hipkins V
Published: April 2011

Genetic diversity of allozymes at 24 loci was studied in 23 populations of longleaf pine (Pinus palustris Mill.), including three seed orchard populations and an old-growth stand. Overall, the mean number of alleles per polymorphic locus was 2.9, the percentage of polymorphic loci was 92%, and the mean expected heterozygosity was 0.105. These values are comparable with diversity measures found in a similar loblolly pine (Pinus taedaL.) study. Diversity measures of the seed orchard sources and the old-growth stand were similar to those in the other natural seed sources. F statistics indicate very little inbreeding overall (FIS = -0.002) and low differentiation among populations (FST = 0.041). All measures of genetic diversity were significantly related to longitude; western sources tended to have more allozyme diversity. Since growth or survival are not related to longitude, and no important climatic variables are related to longitude within the natural range of longleaf, it is proposed that the east-west variation in longleaf pine is a result of migration from a single refugium in the west (south Texas or northeastern Mexico) after the Pleistocene.
A game-theoretic model of timber prices with capital stock: an empirical application to the Finnish pulp and paper industry
Authors: Koskela Erkki , Ollikainen Markku
Published: April 2011

The paper provides a framework to approach price and quantity determination in the roundwood market from a new perspective. In the spirit of the trade union literature, a model of timber price determination is formulated according to which the forest owners' association determines timber prices and then forest firms unilaterally decide on the timber to be used. The novelty here is to incorporate investment decisions of firms as a strategic factor into the model. The structure of the model is the following. The game is played in two stages. First, the forest owners' association and the firms in the forest industry decide on timber price and capital stock, respectively. In the second stage, the firms determine timber demand conditional on the timber price - capital stock game, so that the equilibrium concept is the subgame perfect Nash equilibrium. This game-theoretic model is applied to the annual data from the Finnish pulp and paper industry over the period 1960-1992. Estimation and testing results concerning the price and quantity determination of timber as well as capital stock behavior are generally favorable for the hypotheses presented. In particular, diagnostics and various test procedures indicate that these equations outperform conventional specifications derived from the theory of the demand for factors of production.
Using a geographic information system (GIS) to associate forest stand characteristics with top kill due to defoliation by the jack pine budworm
Authors: Hall R J , Volney WJA , Wang Y.
Published: April 2011

The occurrence and spatial distribution of top kill 1 year following a jack pine budworm (Choristoneura pinus pinus Freeman) outbreak were examined for possible associations with forest stand characteristics derived from resource inventory maps. Associations were computed between top-kill severity and jack pine (Pinus banksiana Lamb.) maturity, stand height, crown closure, and site quality. Three different measures of association with data from a geographic information system (GIS) (Cramer's V, Spearman's nonparametric rank correlation, and Minnick's coefficient of areal determination) were used to assess the strength of these associations. There were no statistical differences among average top-kill lengths, which averaged 2 m, among the light, moderate, and severe top-kill categories. The proportion of trees that experienced top kill ranged from 55% in the light to 61% in the severe top-kill classes. Site quality and stand maturity were more highly associated with top kill than stand height and crown closure. Jack pine areas that sustained moderate and severe top kill were those on poor sites that were overmature (> 85 years), 15-20 m tall with 30-55% crown closure. The GIS approach can be a useful tool for identifying vulnerable stands, and increasingly so as forest inventory classification systems become more detailed.
Five-year growth response of western red cedar, western hemlock, and amabilis fir to chemical and organic fertilizers
Authors: Prescott C E , Brown S M
Published: April 2011

The hypothesis that growth responses of conifers to application of organic fertilizers are of longer duration than responses to chemical fertilizers was tested in two trials on northern Vancouver Island. Both trials were in 10-year-old plantations of conifers on a salal-dominated cutover known to have poor N supply. In Trial 1, western red cedar (Thuja plicata Donn ex D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and amabilis fir (Abies amabilis (Dougl.) Forbes) were treated with municipal biosolids at 542 kg N·ha-1 and 162 kg P·ha-1 or ammonium nitrate and triple superphosphate at 225 kg N·ha-1 and 75 kg P·ha-1. Height increments in the 5 years following applications were two to five times greater in plots treated with either biosolids or fertilizer than in untreated plots. In Trial 2, western red cedar was treated with fertilizer at 225 kg N·ha-1 and 75 kg P·ha-1 or the following organic amendments at 504-610 kg N·ha-1: biosolids, biosolids and pulp and paper sludge, fish silage and wood ash, fish silage with wood ash and pulp and paper sludge, and wood ash alone. Height increments in the 5 years following applications were similar in all treated plots (except wood ash alone). These experiments provided no evidence for sustained growth responses in plots treated with organic fertilizers compared with those treated with chemical fertilizer.
Root chemistry of Douglas-fir seedlings grown under different nitrogen and potassium regimes
Authors: Shaw Terry M , Moore James A , Marshall John D
Published: April 2011

Root chemistry and biomass allocation of Douglas-fir (Pseudotsuga menziesii var. glauca (Bessn.) Franco) seedlings under optimal and deficient levels of nitrogen (N) and potassium (K) were studied. Seedlings receiving high-N treatments were significantly larger and allocated more dry matter to their stems and less to their roots than those receiving the low-N treatments. The K treatments did not significantly affect total seedling biomass or root/shoot ratios. Root tip starch concentrations were significantly higher and root tip sugar concentrations were lower in plants receiving the low-N treatments. Seedlings receiving the high-N, low-K treatment had significantly lower concentrations of phenolics and tannins and lower ratios of these compounds to sugars in the root tips than seedlings receiving the high-K treatments. Samples taken from two locations on the root system show that concentrations of phenolics, tannins, sugars, and starches were substantially higher in the root collar than in the root tips. Because of lower within tissue variation, we recommend sampling at root tips to better detect treatment differences. This study shows that N levels affect starch concentrations in the roots, while K levels affect root phenolic and tannin concentrations. Possible relationships between low root phenolic and tannin concentrations and lessened resistance of Douglas-fir to root disease are discussed.
Assessment of the effects of logging, forest fires and drought on lakes in northwestern Ontario: a 30-year paleolimnological perspective
Authors: Paterson Andrew M , Cumming Brian F , Smol John P , Blais Jules M , France Robert L
Published: April 2011

The frequency and intensity of large-scale watershed disturbances (e.g., clearcuts and wildfires) is increasing in northwestern Ontario. Timber harvesting and wildfires have been shown to alter water quantity and quality in stream ecosystems. Unfortunately, scientific studies of these impacts on lakes are considerably rarer. Using paleolimnological techniques, we examined the remains of scaled chrysophytes in sediment cores from four lakes that have had the majority of their watersheds clearcut, two lakes that have had large forest fires in their watersheds, and two lakes that have had minimal watershed disturbance. Lakes in this study showed minor changes in the composition of scaled chrysophytes at a temporal resolution of 2-4 years, despite removal of over 90% of the forest. Furthermore, temporal variability in the species assemblages were similar in all lakes. A gradual change in the species assemblages of all lakes suggested a regional influence may have been responsible. We hypothesize that hydrological changes brought about by a regional drought from 1970 to 1990 may have exerted an overriding influence on lakes over this time period.
Predicting germination capacity of Pinus sylvestris and Picea abies seeds using temperature data from weather stations
Authors: Almqvist Curt , Bergsten Urban , Bondesson Lennart , Eriksson Urban
Published: April 2011

In Fennoscandia, both Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) often fail to produce mature seed, especially in the northern parts of their range. Therefore, cone and seed crop predictions are of major strategic importance for maintaining sustainable multipurpose forestry. We present functions for predicting germination capacity of Pinus sylvestris and Picea abies seed over a wide geographic area. The functions are based on germination analyses for 1297 Pinus sylvestris and 597 Picea abies natural stands in Sweden during 1971-1994. Meteorological data from 71 weather stations were used to calculate heat sums with threshold values from 4 to 10°C and two durations of growing season (ending August 31 or September 30). Logistic regression was utilised for parameter estimates. Accumulated heat sum (threshold 5°C) from start of growing season until August 31 in combination with number of days from estimated time of fertilisation until approximate time for embryo growth cessation gave the best function. The function shows that Picea abies has lower temperature requirements for producing mature seed than Pinus sylvestris. A germination capacity of 95% is reached at a heat sum of 875 degree-days for Picea abies and at 975 degree-days for Pinus sylvestris.