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Ontario trembling aspen (Populustremuloides Michx.) unmerchantable tops and branches, with and without bark, gave unbleached kraft pulps with greater permanganate numbers and screen rejects than pulps from corresponding boles when cooked by the same schedule. Oven-dried pulp strengths of components, with and without bark, after beating in a P.F.I, mill, were less than those of the oven-dried pulp from an internal standard. Tops and branches with bark yielded pulps with substantially lower strength values than pulps from the tops and branches without bark, and also took longer to beat to 300 ml C.S.F. It is suggested that aspen tops and small-diameter boles without bark could be pulped with wood from mature boles in limited amounts (5–10%) to give a satisfactorily homogeneous pulp. However, inclusion of branches with mature boles, both without bark, would give a more heterogeneous pulp mixture. Any mixtures of tops, small boles and/or branches with bark, and mature boles without bark would give a highly heterogeneous pulp.

The unscreened kraft pulp yields at permanganate No. 14 for 7-, 13-, and 22-year-old trembling aspen (Populustremuloides Michx.) trees from Manitoba for effective alkali applications of 14% were 56.2, 55.7, and 54.8% (o.d. wood), respectively. Specific gravity data for green and ovendry wood are presented, but no relationship with tree height could be established. Pulp strength values from the 7-, 13-, and 22-year-old aspen were, respectively, 60, 67, and 65 for tear factor; 67, 71, and 72 for burst factor; and 10.1, 10.4, and 10.7 (km) for breaking length, respectively. These data indicate that trees of any of the three ages will make a kraft pulp comparable in yield and strength to commercial hardwood–softwood pulp.

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

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

A plug was designed to allow the exchange of atmospheric air and moisture but suppress infection by microorganisms during the development of discoloration associated with wounds in living trees. The design is described.

Because of the large volumes of decayed western hemlock wood available in British Columbia forests a small laboratory study was undertaken to assess the potential quantity of cellulose available from western hemlock wood decayed by Echinodontiumtinctorium. Alpha cellulose and holocellulose yields were determined for a total of 57 wood samples from five trees. On the basis of these limited investigations it appears that holocellulose and alpha cellulose yields from western hemlock wood decayed by E. tinctorium should be nearly equivalent to yields obtained from equal volumes of soundwood. Further investigation of cellulose yields from decayed wood is warranted.

Biomass and nutrient content of natural stands of northern hardwood regeneration were measured 4 years after clearcutting. Pin cherry and shrubs made up a significant proportion of the biomass in both unfertilized and fertilized stands. Yet these stands are well stocked with large numbers of desirable commercial species, especially paper and yellow birch. However, fertilizer greatly stimulated pin cherry to the detriment of the commercial species. Paper birch was the only commercial species to increase in average dry weight on the fertilized area.

This paper describes the spatial pattern, expressed by Pielou's nonrandomness index, of trees within 13 sampled tracts from the major forest types of northern Ontario. Results indicate that: (a) the majority of natural coniferous or mixedwood stands have highly clustered patterns; (b) hardwood stands or the hardwood component of the mixedwood stands show nearly 'random' spatial patterns; and (c) uniform spacing in natural stands is very rare. Results also indicate that spatial patterns vary considerably during stand development for the various species group – size class combinations within a stand and between different forest types. The importance of spatial pattern and stand population dynamics is pointed out with regard to growth simulation modelling and mechanized harvesting and thinning studies.

This paper reports the effects of whole-tree harvesting of eight cottonwood stands on the soil nutrient pool. The data indicate possible site degradation by depletion of soil reserves of N, P, and K but not Ca and Mg on a range of alluvial site conditions in Alabama. Foresters must establish the rate of nutrient removal in intensive tree cropping systems for a variety of species and sites and develop prescriptions to minimize the impact.

The present paper is a companion to a previous report that described the content of dry matter and N, P, K, Ca, and Mg in 30- to 35-year-old stands of Pinusbanksiana Lamb. in northern Ontario. The root systems of eight trees were excavated, weighed, and analyzed for chemical content. Using the regression-stand table method, dry-matter and nutrient content per hectare were estimated. On an areal basis, root weight of P. banksiana was lower than for stands of comparable age of other species located elsewhere. Likewise a smaller proportion of the total plant was in root with P. banksiana.

In a laboratory study stratification had little or no effect on the germination capacity, but it significantly increased the rate of germination in western hemlock seedlots. The greatest increase occurred after 1–2 weeks of chilling on moist filter paper. Naked stratification in plastic bags produced nearly the same response. For stratification longer than 2 weeks, increments in germination rate became progressively smaller. Excellent germinability was indicated by germination values over 30, poor germination by germination values below 13.

This paper presents a method of evaluating site productivity by volume per square foot of basal area, comparing it with the method of dominant height. Based on this method, this study also offers tables for estimating the production of plantations in relation to the average height, the average form quotient, and to the average basal area of the stand. Moreover, this study gives practical instructions about several factors influencing growth and yield of white spruce (Piceaglauca, Moench.) plantations in the province of Quebec.

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.

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.

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 stochastic model is developed to describe it. 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.

In a field trial two 100 acre (40 ha) plots of balsam fir heavily infested with spruce budworm were sprayed with a water-based formulation of a liquid concentrate containing 25% commercial Bacillusthuringiensis Berliner and 25% non-volatile additive. The spray formulation used on one plot contained 5.5 g of the enzyme chitinase added to the 200 gal (757 l) of material. The spray was applied at 2 gal/acre (G.P.A.) (18.6 l/ha) by a Stearman aircraft equipped with 4 Micronair® AU 3000 rotary atomizers. Spray deposits were sampled with paper cards and plates of nutrient medium. A dry dye treatment was used to enhance drop trace visibility on deposit sample cards.Larval mortality was higher on the chitinase treatment plot, and better foliage protection resulted. Biochemical tests indicated some differences in physiological responses in larvae and pupae from the two treatments. It is concluded that, given suitably equipped aircraft, and a guidance system that would ensure uniform coverage, the addition of chitinase should make it practicable as one of the methods of control of the spruce budworm.

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 given site, growth response was not greatest for trees and stands nearest the ditch, but for those some distance away.

This paper presents mathematical equations describing the relationships between the amount of stemflow per canopy layer per storm and the amount of gross rain per storm for four different canopy layers in a multi-storied forest community. The curves representing the relationships were curvilinear; for three of the canopy layers stemflow per storm increased at an increasing rate as gross rain per storm increased, approaching a constant rate of increase. Numerical values of the equation coefficients varied with canopy level in the forest stand profile and with variations in vegetal structure within the forest community. The lowest canopy in the vegetal profile, a fern canopy, had the most marked effect on rainfall redistribution.

In this paper a technique is proposed which finds a unique linear predictor which is used to construct volume tables for different tree species, when it is multiplied by proper scaling factors. This technique uses the fact that one species can give information about some other. This information can be used in future studies where data are not available on all the species considered.

In this paper, several observations are presented to point out the behavior of systematic sampling in forest inventory. A brief literature review and the results of empirical studies indicate that the relative precision of two-dimensional systematic sampling for a given forest stand varies with the variable of interest, spatial distribution of trees, plot size, and sampling intensity. More specifically, results of this study indicate that systematic sampling performs better than or as well as simple random procedures for clustered or near-randomly distributed forest populations for tree frequency estimation. For uniformly spaced populations such as plantations, however, simple random sampling should be most precise for tree frequency estimation. With basal area, results were less clear but considering this study plus others reported in the literature, systematic sampling should usually perform as well as or better than simple random procedures for most tree populations.

This paper presents results of measurements, made separately for each of four canopy layers, of throughfall and stemflow in a multilayered stand of largetooth aspen (Populus grandidentata Michx.). Each canopy layer is identified by the predominant woody or fern species. Equations describe relationships between stemflow, stem size, and storm size, and between throughfall and storm size. In general, stemflow per stem per storm increased as both stem size and storm size increased, the latter having the greater effect. The equations varied with species. General stemflow equations were constructed to calculate stemflow per stem per storm for tree sizes and storm sizes within the measured range. Throughfall per storm increased as storm size increased, but at different rates for different canopy layers. Monthly budgets of interception, stemflow, and net rainfall for the various canopies, separately and together, were computed for the summer months of 1969 using the stemflow and throughfall equations, measured gross rainfall during all summer storms, and data on canopy structure for four plots within the stand. Interception by all canopies together amounted to 22 to 46% of monthly gross rainfall. Interception from the bracken fern canopy alone was 3 to 9%. Stemflow was about 8 to 17% of the monthly gross rainfall. The highest proportion of total stemflow was from bracken fern. Net rainfall was 54 to 78% of the monthly gross rainfall.