摘要:

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 curves based on index age 100 years at BH. The curves were constructed using the regression method and stem analyses of 181 dominant white spruce trees (Piceaglauca(Moench) Voss). Using curves based on index age 100, a 10-ft index class could not be identified with 95% confidence for BH ages below about 50 years even if these curves were entered with sample averages of 50 dominant heights. Using curves based on index age 50, a 10-ft index class could be identified with 95% confidence for BH ages 20–100 years if these curves were entered with sample averages of at least 15 dominant heights. Effect of index age on the outcome of curve shape comparisons was discussed.

ISSN:0045-5067    

DOI:10.1139/x73-001

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Pathogenicity ofCenangiumferruginosumFr. ex Fr.,Dermeabalsamea(Pk.) Scaver,D.piceinaGroves,Potebniamycesconiferarum(Hahn) Smerlis, andPragmoporapithya((Fr.) Fr.) Groves was confirmed and demonstrated on additional tree species. Pathogenicity of the following was demonstrated for the first time:Ascocalyxlaricina(Ettl.) Schläpfer,Biatorellaresinae(Fr.) Mudd,DermeapinicolaGroves,Lachnellulaagassizii(Berk. & Curt.) Dennis,L.arida(Phill.) Dennis,L.gallica(Karst. & Har.) Dennis,L.occidentalis(Hahn & Ayers) Dharne,PotebniamycesbalsamicolaSmerlis var.balsamicola, andPragmoporaamphibolaMassal. Inoculations withAscocalyxabietisNaumov,Lachnellulaciliata(Hahn) Dennis,L.suecica(de By. ex Fckl.) Nannf.,Odontotremahemisphaericum(Fr.) Rehm,Peziculalivida(Berk. & Br.) Rehm, andTryblidiopsispiceaVel. were negative.

ISSN:0045-5067    

DOI:10.1139/x73-002

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

An unusual feeding behavior of the western spruce budworm (ChoristoneuraoccidentalisFreeman) reduced height growth and deformed young western larch (LarixoccidentalisNutt.). On western larch, budworm larvae did not confine their feeding to foliage, their usual diet on other conifers; they also fed on and severed stems of current-year terminal and lateral shoots. A 5-year study in young larch stands showed that: (1) amount and severity of budworm damage increased annually, (2) all trees were damaged sometime during the study, (3) severance of the terminal shoot was the most serious type of budworm damage to larch, (4) severances reduced net height growth at least one-fourth and resulted in forked, bushy-topped trees, and (5) specific forks in the tree did not persist more than 5 years because of the strong apical dominance characteristic of larch.

ISSN:0045-5067    

DOI:10.1139/x73-003

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

An experiment is described which was carried out to examine the feasibility of using 10 years of growth of tree branches as the basis for an estimate of the trace element status of forest trees and stands. The experiment was undertaken to obtain an estimate of trace element status of forest trees (or stands) independent of 'within season' or 'season to season' variations in the chemical composition of the branches. Thirty-six trees, twelve of each of three species (Betulapapyrifera,Populusgrandidentata,Populustremuloides), growing together in a 50 year old mixed wood stand at Chalk River, Ontario were included in the experiment. On the basis of tree growth data and measurements of the content of two micronutrient elements (copper and zinc) and two nonnutrient elements (lead and nickel) in 360 samples of branch material it was concluded that the proposed method of determination of the element status of forest trees (or stands) shows promise, but requires more detailed study before its importance as a method of trace element status estimation can be fully evaluated.

ISSN:0045-5067    

DOI:10.1139/x73-004

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Bud diameter, bud length, and shoot length varied widely in different shoot locations of 8-year-oldPinusresinosatrees. Over all locations and shoots within each tree, bud diameter and bud length, bud diameter and shoot length, and bud length and shoot length were highly correlated. Bud length was a better index than bud diameter of final shoot length. Over all trees and shoots within each location, the correlations between (1) bud diameter and bud length, (2) bud diameter and shoot length, or (3) bud length and shoot length were higher in upper whorl branches than in the terminal leader. Bud diameter and bud length were better indicators of shoot growth for upper whorl branches than for lower whorl branches or the terminal leader.

ISSN:0045-5067    

DOI:10.1139/x73-005

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The effect of gibberellic acid (GA3) on suckering from trembling aspen (PopulustremuloidesMichx.) roots was determined by treating two kinds of root cuttings, one that produced suckers from primordia newly initiated or in an early stage of development (EP roots) and another that produced suckers primarily from relatively large, visible primordia (LP roots). Also investigated was the effect of an inhibitor of gibberellin action, a substituted pyrimidine, on outgrowth of suckers from LP roots. All concentrations (25–400 mg/l) of GA3stimulated shoot outgrowth from LP roots. In contrast, GA3inhibited shoot development in EP roots. The role of endogenous gibberellin in sucker outgrowth was indicated by the inhibition of shoot elongation by the inhibitor of gibberellin action.

ISSN:0045-5067    

DOI:10.1139/x73-006

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The origin and development of adventitious shoots (suckers) from the roots of trembling aspen (PopulustremuloidesMichx.) 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.

ISSN:0045-5067    

DOI:10.1139/x73-007

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

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 NH4+-N and total-N in throughfall but not in stemflow. In both stemflow and throughfall, highest concentrations of nitrogen were recorded in June. The estimated nitrogen returned to the ground by litterfall, throughfall, stemflow, and unintercepted rain was 16.00, 4.33, 0.04, and 2.62 kg N/ha/year.

ISSN:0045-5067    

DOI:10.1139/x73-008

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

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 fulfilled, a lapse of several years between good cone crops is probable.

ISSN:0045-5067    

DOI:10.1139/x73-009

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

NectriafuckelianaBooth var.macrospora(Wr.) Booth was commonly associated with open, resinous cankers of dwarf mistletoe swellings of western hemlock (Tsugaheterophylla(Raf.) Sarg.) in British Columbia, Canada. Pathogenicity of the fungus was proved by artificial inoculation and reisolation from cankered tissues. Cankers substantially reduced dwarf mistletoe reproduction.

ISSN:0045-5067    

DOI:10.1139/x73-010

出版商:NRC Research Press    

年代:1973

数据来源: NRC