摘要:

The performance of Holgate's mean ratio and correlation tests was intensively evaluated on five 48-acre forest tracts and four computer-redistributed populations with specified spatial distribution patterns generated from each tract. These two test statistics were calculated for all possible combinations of distances to thesthandtth(s < ts = 1, 2, 3, 4 andt = 2, 3, 4, 5) nearest trees from each of the 200 randomly selected points. Results indicated that the ratio test may lead to erroneous conclusions when applied to nonrandom distributions. The correlation test was very powerful in detecting regular spacing, but it was not very sensitive in detecting aggregation.

ISSN:0045-5067    

DOI:10.1139/x72-014

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Populations of the spruce bud midge (RhabdophagaswaineiFelt) were sampled on 1 to 6 ft tall black and white spruces (Piceamariana(Mill.) BSP. andP.glauca(Moench) Voss) in central Alberta. The incidence of attacked buds is described in relation to tree height and crown aspect, and in relation to terminal buds of the leader and top whorl branches. Some characteristics of the infested bud are given to assist in its recognition in the field.After leader terminal buds of young white spruce were removed to simulate midge damage, height loss during the same year averaged 25.3%. Normal height growth was resumed in the following year from an apical-dominant lateral branch. The study suggested that, for general surveys, a count of the number of attacked terminal leader buds in young spruce could provide a useful index of midge abundance and provide the basis for estimating its impact on tree height growth.

ISSN:0045-5067    

DOI:10.1139/x72-015

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

In this paper estimates of tree volume, volume by DBH classes, mean volume per plot and their estimated variances are studied. It is suggested that there are three sources of error. These arise from sampling, the volume equation, and grouping. To illustrate the possible effects of these errors on volume estimates, formulae are presented and an example is calculated. A proposed method of volume estimation which combines and accounts for these errors is recommended.

ISSN:0045-5067    

DOI:10.1139/x72-016

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Release ofCronartiumcomandraePk. aeciospores from stem cankers onPinuscontortaDougl. var.latifoliaEngelm. in southwestern Alberta occurred from mid-May to late August, the peak period being between late May and mid-June, after which there was a gradual decrease. Diurnal aeciospore periodicity showed spores to be usually released between 0800 and 1900 hours, with some evidence for a double peak. Maximum daily concentration of trapped spores at a distance of 2.5 cm from the canker was 17 217 spores/m3, but on more than half the days fewer than 100 spores/m3were collected. The highest hourly concentration observed from an individual canker was 128 200 spores/m3, which coincided with the onset of heavy rain. Atmospheric turbulence was associated with all peak aeciospore concentrations. Little release occurred when temperatures were below 7 °C, when relative humidity levels were high, or when dew was present. Peak release occurred when air temperatures were above 20 °C and relative humidity levels were at their lowest. Heavy rains initially increased spore concentrations, but light rains did not have the same effect. Wind was important for initiation of spore release, but there was no close correlation between high wind velocities and high spore concentrations released from a canker.

ISSN:0045-5067    

DOI:10.1139/x72-017

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and manganese (Mn) were examined in September, 1969, in leaves of different ages from different parts of the crowns of twelve 30- to 33-year-oldPinusbanksianaLamb. growing in a natural stand on coarse glacio-fluvial soil in northern Ontario. Although considerable tree-to-tree variability did occur, it was not sufficient to obscure differences related to crown position and leaf age, except in the case of N, where no trends were demonstrable. Foliar P, K, and Mg concentrations were shown to decrease with increasing leaf age, whilst foliar Ca, Fe, and Mn concentrations were shown to increase. From top to bottom of the crown, foliar P, K, and Fe concentrations decreased, whilst Ca and Mn concentrations increased. For Mg, no trend relative to crown position was discernible. Coefficients of variation were calculated and compared as were numbers of sample trees needed for statistically reliable samples.

ISSN:0045-5067    

DOI:10.1139/x72-018

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Consideration is given to the distribution of growth increment at 6 points up the stem of Douglas-fir (Pseudotsugamenziesii(Mirb.) Franco) 5 years after fertilization. The fully stocked stand, near Port Alberni, B.C., was 49 years old with heights and diameters reaching 100 ft and 20 in. respectively when fertilized with 220 and 440 lb/acre of urea. No change of consequence occurred in tree form in the codominant and intermediate crown classes as a result of the volume response which was still evident, although greatly diminished, after 5 years. In dominant trees, however, cross-sectional area growth in the central third of the stem was less than the controls even though other parts of the bole showed a positive response which lasted until the 4th year. The net volume response was negligible. The estimation of volume response to fertilization in dominant trees from breast-height measurements should possibly be approached with caution.

ISSN:0045-5067    

DOI:10.1139/x72-019

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The relationship between leaf production and wood production in two clones ofPopulusgrown for 1 year under intensive culture was investigated. Wood weight at any one stem position was highly correlated with the cumulative leaf area above that position. About one-half the total stem weight was bark, but the bark/wood ratio decreased with increasing leaf area. Wood specific gravity in creased from stem top to stem base, with mid-stem values of about 0.35. Leaf surface area and leaf dry weight were highly correlated with leaf lamina length; the latter therefore provides an easily measured, non-destructive estimate of photosynthesizing leaf surface. Marked clonal differences existed in all parameters measured.

ISSN:0045-5067    

DOI:10.1139/x72-020

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Two methods for detecting dead plant tissue before visual symptoms appear were evaluated. In one method, the rate of recovery of the bioelectrical potential of tissue to its original level after passage of an electric current was tested as an indicator of dead tissue and found unsatisfactory; in the other method, the change in wave form of a square wave electrical pulse passed through plant tissue was the indicator. With this method, leaf tissue from Doublas-fir (PseudotsugamenziesiiMirb. (Franco)) that had been killed by freezing, steaming, or treatment with an herbicide could be detected. Dead leaf tissue of other species could also be detected, but the damaged tissue had to be compared with undamaged tissue of the same species.

ISSN:0045-5067    

DOI:10.1139/x72-021

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Many trees in stands of Douglas fir, western hemlock and western red cedar on Vancouver Island were joined by functional grafts. In a partially cut stand, 45% of the stumps showed evidence of continued growth and half of these (23%) were still growing vigorously more than 22 years after logging. On experimentally detopped trees, growth extended several meters up the bole. Dominant trees usually supported the growth of the root system and lower boles of grafted suppressed trees.Translocation through grafts may partially explain the frequent stagnation and slow recovery of stands after thinning from above, and may be involved in the usually rapid increase of growth after thinning from below. It is probably a contributing factor in establishing dominance and determining mortality in overtopped trees. In species that graft freely, the use of silvicides in spacing and thinning treatments should be restricted to young stands before grafts are established.

ISSN:0045-5067    

DOI:10.1139/x72-022

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Changes taking place at the base of stem cuttings of Douglas-fir during callus formation and root initiation are described. Material was taken from nine sources, including trees of different ages and with different histories of rooting response. Gross morphology and anatomy of the cutting bases are described using serial longitudinal sections of samples taken on a weekly basis over a 4-month period. The basal callus proliferated from the lowest cells of the vascular cambium and a complex pattern of differentiating vascular tissues arose within the callus mass. The root primordia arose in this callus in association with the differentiating phloem and wound cambium. Variation in callus formation and root initiation is described both within and between clones.

ISSN:0045-5067    

DOI:10.1139/x72-023

出版商:NRC Research Press    

年代:1972

数据来源: NRC