Showing papers in "Canadian Journal of Forest Research in 1973"
TL;DR: In this article, Van Wager et al. derived a relation between fire behavior and crown scorch height from measurements on 13 outdoor fires, including fire intensities from 16 to 300 kcal/s-m, and scorch heights from 2 to 17 m.
Abstract: VAN WAGNER, C. E. 1973. Height of crown scorch in forest fires. Can. J. For. Res. 3, 373-378. A relation between fire behavior and crown scorch height is derived from measurements on 13 experimen tal 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.
345 citations
TL;DR: The desirability and the advantages of deriving taper equations from existing volume equations are discussed and it is demonstrated that the most common types of volume equations can be converted to tapers.
Abstract: The desirability and the advantages of deriving taper equations from existing volume equations are discussed. It is demonstrated that the most common types of volume equations can be converted to c...
89 citations
TL;DR: A new competition index, modified Area Potentially Available (APA), was tested in a complex unevenaged stand composed of 19 different hardwood species and exhibits a strong correlation with individual tree basal area growth.
Abstract: A new competition index, modified Area Potentially Available (APA), was tested in a complex unevenaged stand composed of 19 different hardwood species. APA considers tree size, spatial distribution, and distance relationships in quantifying intertree competition and exhibits a strong correlation with individual tree basal area growth. The most important characteristic of APA is its potential for evaluating silvicultural practices.
88 citations
TL;DR: The role of carbohydrate reserves in initial sucker growth from excised roots of Alaskan and Utahan aspen was investigated by correlating the seasonal variation in sucke...
Abstract: The role of carbohydrate reserves in initial sucker growth from excised roots of Alaskan and Utahan aspen (Popnlustremuloides Michx.) was investigated by correlating the seasonal variation in sucker production in darkness with the concentration of total nonstructural carbohydrates (T.N.C.) in the roots. Sucker numbers were not correlated with T.N.C. content. Dry weight of suckers per cutting (D.W./C) was a function of T.N.C. percentage and the number of suckers per cutting (No./C). In the additive model, D.W./C = b0 + b1 (No./C) + b2 (T.N.C), T.N.C. was a significant contributor to sucker dry weight. Although dry weight per cutting increased as the number of suckers became larger, dry weight per sucker decreased. Within geographic area, number and dry weight of suckers and T.N.C. percentage were related to both date of collection and clone of origin. Seasonal trends in T.N.C. content were similar in the Utahan and Alaskan roots studied.
81 citations
TL;DR: The results of this study indicate that a Poisson model with the average number of fires per day depending on the Fine Fuel Moisture Code is appropriate.
Abstract: This paper discusses the occurrence of man-caused forest fires during the summer fire season in a section of northwestern Ontario. Fire occurrence is viewed as being a chance process and a stochast...
79 citations
TL;DR: When branches of white pine are stressed by tying into loops, marked increases in the ethylene content of the internal atmosphere are noted and it is suggested that ethylene may serve as a natural stimulator of radial growth associated with physical stress such as results from wind action.
Abstract: When branches of white pine are stressed by tying into loops, marked increases in the ethylene content of the internal atmosphere are noted. When an ethylene-generating paste is applied to localized regions, growth in diameter is increased there. It is suggested that ethylene may serve as a natural stimulator of radial growth associated with physical stress such as results from wind action.
68 citations
TL;DR: Vascular trace shows that the developing sucker responds to polarity in the root; it grows distally as it extends inward and basipetally to the root cambium, and Lenticels on aspen roots are illustrated.
Abstract: The origin and development of adventitious shoots (suckers) from the roots of trembling aspen (Populustremuloides Michx.) are described. Root suckers originate from newly initiated meristems, preexisting primordia, or suppressed short shoots, but the first two are probably the most important in sucker production. Preformed shoot primordia, protuberances from the phellogen, appear to occur on roots throughout the entire aspen range. Evidence was found of suppressed short shoots in aspen roots but not of suppressed buds buried in the periderm. Vascular trace shows that the developing sucker responds to polarity in the root; it grows distally as it extends inward and basipetally to the root cambium. Lenticels on aspen roots are illustrated.
62 citations
TL;DR: This paper is based in large part on recent reviews of tree breeding programs in the southeastern United States, the Pacific Northwest, New Zealand, southeastern Australia, and Taiwan, and the physical movement of gene packages between plantations and forests is presented.
Abstract: This paper is based in large part on recent reviews of tree breeding programs in the southeastern United States, the Pacific Northwest, New Zealand, southeastern Australia, and Taiwan. Domestication, which here includes tree breeding, is discussed generally in terms of original species variability, the processes of selection and packaging, and the returns via a more useful renewable resource. Six reasons why forest geneticists and tree breeders plant trees are given, along with the different requirements for site, planting design, number of trees, and number of entry genotypes or lines for each reason. A flow chart is presented, showing the various kinds of plantations and forests established during a domestication program, and the physical movement of gene packages between such plantations and forests. The information flow within the scheme is also discussed.
55 citations
TL;DR: The relationship between water stress and rates of net photosynthesis, respiration, and transpiration was determined for four Abies species native to Canada and it was found that A. grandis was affected the least by water stress, whereas that of A. balsamea wasaffected the most.
Abstract: The relationship between water stress and rates of net photosynthesis, respiration, and transpiration was determined for four Abies species native to Canada. Net photosynthesis, after an initial optimum rate, declined in three phases as water stress increased, viz. a rapid linear rate of decline, a second more gradual reduction and, finally, a steady rate of zero net photosynthesis. Of the four species, photosynthesis of A. grandis was affected the least by water stress, whereas that of A. balsamea was affected the most. Respiration declined at about the same water stress as photosynthesis, but was only reduced to between 40–75% of the maximum rate, depending on the species. Transpiration declined at similar water stresses to those of photosynthesis and after an initial decline, continued at between 10–30% of the maximum rate at water stresses up to 35 bars.
51 citations
TL;DR: Bud diameter and bud length were better indicators of shoot growth for upper whorl branches than for lower whorL branches or the terminal leader in Pinusresinosa trees.
Abstract: Bud diameter, bud length, and shoot length varied widely in different shoot locations of 8-year-old Pinusresinosa trees. Over all locations and shoots within each tree, bud diameter and bud length,...
50 citations
TL;DR: Frontalin, a synthetic attractant developed from the southern pine beetle, induced spruce beetle attacks on preselected spruce trees destined for harvest, and adjacent trees, and attacked unbaited trees appeared to be related to tree size.
Abstract: 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.
TL;DR: Results indicate that number of survivor trees can be predicted with very good accuracy; predictions of diameter distributions, number of mortality trees, and number of harvested trees are less accurate.
Abstract: A simple stochastic model to predict future diameter distributions, number of survivor trees, number of mortality trees, and number of harvested trees is developed from conventional continuous fore...
TL;DR: Fertilization and cultivation before and after planting greatly increased 9-year growth and yield of longleaf, slash, and loblolly pines, and genetic variation was found in response to intensive culture.
Abstract: 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.
TL;DR: Both individual tree and stand growth responded well to draining, with younger and more vigorous trees that were growing on better-quality sites showing the greatest response.
Abstract: This paper presents a growth analysis of a forest drainage experiment carried out over 40 years in northern Ontario. It is based on remeasurement data obtained in 1969 from 38 growth plots established following drainage in 1929 and from increment cores and sectioned trees.Results indicate that both annual tree diameter and height growth increased significantly after draining; that tree growth before draining was related to site quality only, while after draining it was related also to tree vigor and distance of water flow from the nearest ditch; that both stand diameter and height growth were related to site index, stand age, and initial stocking; and that stand basal area and volume growth were, in addition, related to a product sine function of distance of water flow from the ditch, peat moisture, decomposition, and depth.Both individual tree and stand growth responded well to draining, with younger and more vigorous trees that were growing on better-quality sites showing the greatest response. For a gi...
TL;DR: While an inorganic source of nitrogen was sufficient for the rapid growth of buds, the addition of organic nitrogen to the medium consistently promoted growth, but changes in weight and axis length were not always significant.
Abstract: Resting, vegetative buds of white spruce, black spruce, Norway spruce, balsam fir, and Douglas-fir were grown under aseptic conditions on agar with various supplements. While an inorganic source of nitrogen was sufficient for the rapid growth of buds, the addition of organic nitrogen to the medium consistently promoted growth, but changes in weight and axis length were not always significant. For white spruce, all levels of growth regulators inhibited bud development. Coconut milk supported organized growth. Malt extract and casein hydrolysate were not beneficial. Levels of sugar above 2% (w/v) greatly improved the weight and length of the emerging shoot.The extent of shoot formation depended on the portion of dormant bud which was used as starting material. Buds isolated with an attached crown and intact embryonic shoot grew faster than those excised above this nodal diaphragm. By 40 days, the fresh weight of isolated buds increased 15–20 times, and their axes elongated 5–6 fold. Needles of some species ...
TL;DR: In this article, the nitrogen contents of stemflow, throughfall, litter, and rain were investigated in a black spruce stand with 95% crown closure treated with three levels each of nitrogen and phosphorus fertilizers in a factorial design.
Abstract: The nitrogen (N) contents of stemflow, throughfall, litter, and rain were investigated in a black spruce stand with 95% crown closure treated with three levels each of nitrogen and phosphorus fertilizers in a factorial design. Throughfall and rain were collected in standard rain gauges. Stemflow was collected using lead collars coated with an inert plastic and fixed on the tree trunks. Litter samples were collected with fiberglass screens. In all samples, NH4+-N and total-N were determined.During this study, 18–20% of the rainfall was lost through interception and evaporation, 80% was throughfall, and less than 0.5% reached the ground as stemflow. Average concentrations of NH4+-N for all fertilized plots in stemflow, throughfall, and rain were 0.15, 0.23, and 0.09 p.p.m. N, respectively, and the total-N in these samples was 1.69, 0.63, and 0.37 p.p.m. N in the same sequence. Quantities of nitrogen in the throughfall were highest in the fertilized plots, i.e. fertilization increased the concentration of NH...
TL;DR: Analysis of age data in these fire-dependent communities in Glacier National Park, Montana, indicates that ponderosa pine is not reproducing itself as well as other mesophytic conifers invading these stands.
Abstract: Ponderosa pine (Pinusponderosa Laws.) forest communities in Glacier National Park, Montana, were investigated to determine the effects of fire exclusion. Analysis of age data in these fire-dependent communities indicates that ponderosa pine is not reproducing itself as well as other mesophytic conifers invading these stands. In addition to these compositional changes, it was determined that fuel accumulations are greater in these park communities compared with similar wilderness area pine communities subject to more recent burning.
TL;DR: With 3rd-instar larvae sprayed with a suspension of the virus Borrelinavirusswainei (Smirnoff), viral infection developed much more rapidly in larvae placed on fertilized trees, mortality reaching 100%, double that measured on unfertilized trees.
Abstract: Mortality of the Swaine jack-pine sawfly larvae (Neodiprionswainei Midd.) introduced as colonies on jack-pine (Pinusbanksiana Lamb.) foliage was measured in untreated and urea-treated plots of natural forest. Following applications of urea (400 kg N/ha) repeated in two successive years, natural mortality increased from 40 to 70% after 4 weeks, from 33 to 51% after 6 weeks, and from 18 to 36% after 4 weeks for larvae introduced as 1st instar, 2nd instar, and 3rd instar, respectively. This was accompanied by a marked reduction in foliage consumption as revealed by direct measurements or by the weight of frass collected. With 3rd-instar larvae sprayed with a suspension of the virus Borrelinavirusswainei (Smirnoff), viral infection developed much more rapidly in larvae placed on fertilized trees, mortality reaching 100%, double that measured on unfertilized trees. Single applications of urea at lower rates (100 and 200 kg N/ha) revealed a trend of increasing mortality for both unsprayed and virus-sprayed larv...
TL;DR: In this paper, fuel weight and biomass distribution in a 51-year old lowland and a 55-year-old upland black spruce (Piceamariana [Mill.] B.S.P.) stand in interior Alaska were reported.
Abstract: This study reports the fuel weight and biomass distribution in a 51-year-old lowland and a 55-year-old upland black spruce (Piceamariana [Mill.] B.S.P.) stand in interior Alaska. Biomass distribution is shown for overstory, standing and down dead tree components, herbaceous understory, and the moss layer. The lowland stand contained over 11000 stems/acre (27170 stems/ha) and 82 ft2 of basal area per acre (18.8 m2 of basal area per hectare), and the upland stand contained 6000 stems/acre (14820 stems/ha) and 96 ft2 of basal area per acre (22.0 m2 of basal area per hectare). Moss layers contributed 54.6 and 45.5 t/acre (120.1 and 100.1 metric t/ha) to biomass totals in the lowland and upland sites, respectively. Total biomass was 64.7 t/acre (142.3 metric t/ha) in the lowland site and 58.0 t/acre (127.6 metric t/ha) in the upland site.
TL;DR: Seasonal variation in number of suckers produced from root cuttings of three clones of trembling aspen was related, in a negative manner, to the quantity of endogenous auxin in the roots when collected.
Abstract: 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.
TL;DR: Urea promoted aphid establishment and reproduction, whereas ammonium nitrate affected these processes, as well as survival, adversely, adversely and the highest establishment and survival rates resulted from potassium ammonium Nitrate.
Abstract: Balsam woolly aphids were reared on young grand fir trees maintained in controlled environment or outdoors. Solutions of various nitrogen fertilizers were applied repeatedly to the trees and the effects on aphids and bark amino acids were studied. On trees fertilized with ammonium nitrate or a sequence of compounds, aphid population growth was less than on trees fertilized with urea or potassium ammonium nitrate. On urea-fertilized trees, populations multiplied 16.5 times in five generations, compared with a 5.7-fold increase on unfertilized trees and a 1.4-fold increase on ammonium nitrate-fertilized trees. These differences resulted from effects of these nutrients on aphid life history. Urea promoted aphid establishment and reproduction, whereas ammonium nitrate affected these processes, as well as survival, adversely. The highest establishment and survival rates resulted from potassium ammonium nitrate.These differences may be related to fertilizer-induced changes in the amino acid diet of the aphid. T...
TL;DR: Thirty-six-year records of Douglas-fir and grand fir cone counts were analyzed with eight climatic variables to find which combinations of climatic factors were related to the induction of reproductive buds and the successful development of the strobili.
Abstract: Thirty-six-year records of Douglas-fir and grand fir cone counts were analyzed with eight climatic variables to find which combinations of climatic factors were related to the induction of reproductive buds and the successful development of the strobili. Cool, cloudy weather during June, July, and August, 26–24 months before cone maturation, was the first prerequisite for abundant reproductive bud initiation. The second was cold, sunny weather during December, January, and February, 20–18 months before cone maturation. A wet April, 16 months before cone maturation, resulted in a higher proportion of megasporangiate strobili being differentiated, while a warm, dry, sunny June, 14 months before cone maturation, favored successful bud development. Since the prerequisites for a good cone crop include an alternation of cool, moist summers (2 years prior) and warm, dry summers (1 year prior), good cone crops in two consecutive years can not be expected. And since additional environmental prerequisites must be f...
TL;DR: In this article, a pattern of chemical and morphological changes occurred in sugar maple wood that formed after wounding, resulting in a distinct tissue, and after normal wood formation resumed, this wound-associated tissue separated wood formed subsequently from wood formed before wounding.
Abstract: A pattern of chemical and morphological changes occurred in sugar maple wood that formed after wounding, resulting in a distinct tissue. After normal wood formation resumed, this wound-associated tissue separated wood formed subsequently from wood that formed before wounding. Discoloration associated with the wound developed in the wood extant prior to wounding.
TL;DR: A preliminary comparison of burned and unburned tracts in the northern boreal forest of the lower Mackenzie River valley indicates that, without periodic fires, trees will be eliminated and the cli...
Abstract: A preliminary comparison of burned and unburned tracts in the northern boreal forest of the lower Mackenzie River valley indicates that, without periodic fires, trees will be eliminated and the climax vegetation will be a moss/lichen association. The implications for land management are adumbrated.
TL;DR: Evidence is presented which emphasizes the importance of food reserves and conditions controlling late-season photosynthesis to subsequent-year shoot growth of Pinusresinosa to utilization of reserve photosynthates of the prior-year internode.
Abstract: Evidence is presented which emphasizes the importance of food reserves and conditions controlling late-season photosynthesis (e.g. during bud development) to subsequent-year shoot growth ofPinusres...
TL;DR: Concentrations of N, P, K, Ca and Mg were determined in aerial components of jack pine [Pinitsbanksiana Lamb] trees growing in 12 stands, representing three age classes, two site classes, and two...
Abstract: Concentrations of N, P, K, Ca, and Mg were determined in aerial components of jack pine [Pinitsbanksiana Lamb.] trees growing in 12 stands, representing three age classes, two site classes, and two...
TL;DR: Length of the growing season and grand period growth rate were positively correlated, and Dates of growth initiation and growth cessation were also positively correlated.
Abstract: Daily height increment of trees was measured throughout two growing seasons as was 2-day radial increment of 212 of the same trees in the second season. The relationships between phenological variables and total growth, and the effect of environment on short term growth were assessed. Inferences taken from the latter data were tested on seedlings under more controlled conditions in the laboratory. The arbitrarily defined dates of initiation and cessation of growth, and the grand period growth rates were read from the growth curves. The respective simple r2 values between these variables and height growth were 0.10, 0.40, and 0.71, and r2 for the multiple regression of height growth and these variables was 0.94; for radial growth these values were 0.07, 0.56, 0.64, and 0.94. Length of the growing season and grand period growth rate were positively correlated. Dates of growth initiation and growth cessation were also positively correlated.Daily height growth varied considerably, depending strongly on temper...
TL;DR: In this paper, a root injection of methyl 2-benzimidazole carbamate (MBC)-phosphate was performed on 12 healthy, mature, field-grown white elms (Ulmusamericana L.) and one with severe symptoms of Dutch elm disease.
Abstract: Methyl-2-benzimidazole carbamate (MBC) was solubilized by formation of salts (MBC-phosphate, -nitrate, -hydrochloride, -sulfate, and -sodio derivative). All the salts of MBC exhibited greater fungitoxicity towards Ceratocystisulmi than the parent compound and lower phytotoxicity towards elms. MBC-phosphate was root injected into 12 healthy, mature, field-grown white elms (Ulmusamericana L.) and one with severe symptoms of Dutch elm disease. Controls consisted of seven elms injected with distilled water alone. To date, bioassays of trees treated with MBC-phosphate using the root-injection method have demonstrated extremely good distribution throughout the tree at a concentration which, on the basis of laboratory tests, is sufficient to arrest development of C. ulmi. Treated elms could not be successfully inoculated with C. ulmi conidia, whereas control trees could. Recovery of C. ulmi from the diseased elm was greatly reduced after root injection with MBC-phosphate.
TL;DR: Equations were developed from single and repeated stem counts, diameter and height measurements to predict leafless aerial biomass, net productivity, and stem survival in young trembling aspen sucker stands on good to excellent sites.
Abstract: Equations were developed from single and repeated stem counts, diameter and height measurements to predict leafless aerial biomass, net productivity, and stem survival in young trembling aspen sucker stands on good to excellent sites. Although the most dense stands studied reached maximum periodic annual productivity at age 16, maximum mean annual productivity will not be reached until after 20 years of age.
TL;DR: Effect of index age on the probable size of random error in site index was evaluated by comparing the 95% confidence interval for site index by curves based on index age 50 years at breast height (BH) with that by curve age 100 years at BH.
Abstract: Effect of index age on the probable size of random error in site index was evaluated by comparing the 95% confidence interval for site index by curves based on index age 50 years at breast height (...