Thesis (M.S.)--Oregon State University, 1986. / Typescript (photocopy). Includes bibliographical references (leaves 104-111). Also available on the World Wide Web.

Five plant associations and one Alluvial Complex are recognized for the Dry Subzone of the Interior Western Hemlock Zone of British Columbia. These include 22 phytocoenoses, here described as biogeocoenoses or forest types. Additionally 3 intrazonal Pinus ponderosa plant associations and 2 interzonal ecotones are discussed. In phytosociological analysis modified Zurich-Montpellier techniques are employed. For tree studies, dominance/ frequency/density (DFD) indices and standard forestry methods are applied. Phytocoenose descriptions are based on synthesis tables which include plant lists (total 538 species), habitat descriptions and tree growth data from 15.5 one-fifth acre plots. Forest types comprise: 1) Lichen association (Cladonietum) - open stands with Pseudotsuga menziesii as the edaphic climax dominant, occurring on xeric rock outcrops; 2) Moss association (Pachistimeto-Callier gonelletum) - closed stands with Tsuga heterophylla as the climatic climax dominant, occuring on me sic sites; this includes 6 forest types; 3) Aralia Oakfern association (Aralieto-Gymnocarpietum) - closed stands with Tsuga heterophylla, Thuja plicata as the edaphic climax codominants, occuring on moist sites; this includes 7 forest types; 4) Devil's Club association (Oplopanacetum) - closed stands with Thuja plicata as the edaphic climax dominant, occurring on wet sites; this includes 4 forest types; 5) Skunk Cabbage association (Lysichitetum) - open stands with Thuja plicata as the edaphic climax dominant, occurring on water-saturated ground; this includes 2 forest types; 6) Alluvial Complex - unstable riverside vegetation dominated by Populus trichocarpa. The Lichen, Skunk Cabbage and Alluvial Complex communities are floristically the most clearly defined, and are readily recognizable on the basis of lesser vegetation dominants alone. Recognition of mesic communities relies on a characteristic combination of species. The zonal (climatic climax) biogeocoenose is the Slope Normal Moss forest type of the Moss Association. The dynamic relationships of forest types are discussed. Secondary succession may go from the deforested stage directly to the climax, if edaphotope disturbance is minimal, but normally a pioneer-tree stage intervenes. This Subzone is unique in that, the pioneer stage of the zonal community may differ substantially from the climatic climax if humus is removed by fire. On mesic sites, proceeding from pioneer-conifer to climax stages, crown cover decreases and lesser vegetation increases. Tsuga heterophylla is the exclusive dominant of the climax forest„ In decreasing order of importance, as determined by DFD indices, Subzone trees are Tsuga heterophylla, Thuja plicata. Pinus monticola, Pseudotsuga menziesii, Betula papyrifera, Picea engelmannii, Larix occidentalis, Populus tremuloides, Pinus contorta, Populus trichocarpa. Abies lasiocarpa and Abies grandis. Most rapid tree height growth of Thuja plicata, Pseudotsuga menziesii, Pinus monticola and Picea engel-mannii occurs in Devil's Club communities; of Tsuga heterophylla, Larix occidentalis, Pinus contorta, Betula papyrifera, Populus tremuloides in Aralia Oakfern communities; and of Populus trichocarpa in Alluvial Complexes. Forest types are more productive in pioneer than in climax stages. Estimates of net primary productivity and standing crop of forest types for tree trunks of all tree species summed as one, showed that the greatest pioneer- conifer stand productivity (1251 kilogram/ hectare/year) and climax stand standing crop (180 x 10³ kg/ha) belong to the Devil's Club association, and the least productive (126 kg/ha/yr) and lowest standing crop (15 x 10³ kg/ha) to the Lichen association. It is concluded that biogeocoenotic classification provides a sound basis for land use planning in this region, and should be applicable to other areas. / Science, Faculty of / Botany, Department of / Graduate

Quantitative measures of stand density and stocking are very important because only with full knowledge of the growing stock can a forest be managed efficiently. Stocking is concerned with fraction of area occupied with trees. Density is related to the degree of crowding within the area occupied. These quantitative values are determined by parameters that could be measured on the ground and on aerial photographs. The methods used to estimate height, crown width, and crown closure from aerial photographs are thoroughly described. The writer also describes the stocking and density conditions under which trees grow, with illustrations by both theoretical models and actual sample plot crown models. Forty-seven sets of ground and photo-measurements were taken and analysed by simple and multiple regression methods. A comparison of photo and ground values was then made to evaluate the usefulness of aerial photographs for density and stocking measurements. The correlation of the ratio of height (Ht) to crown width (CW) from the ground and photo data to age, site index, crown closure, basal area, adjusted basal area, crowding factor and adjusted crowding factor were also studied. Eight assumptions regarding normality of density and full stocking were made so that the interrelationship between the individual density and stocking measurements could be studied more effectively. It is concluded that Ht/CW ratios are measurable from aerial photographs and shown that they are useful as a measure of stand density and stocking. / Forestry, Faculty of / Graduate

This thesis is concerned with plant associations within the Subalpine Mountain Hemlock Zone as indicators of recreational land use capability. With the field recognition of approximately twenty plants (trees, tall shrubs, low shrubs, and ground plants) all the plant associations within this zone can be identified. Knowing the biogeoclimatic characteristics of the plant associations and the limitations of land for recreation, land use decisions concerning summer recreation can be made. The objectives are to develop criteria for rating the limitation of land for selected recreational activities; to summarize information about the plant associations and biogeoclimatic conditions found within the Subalpine Mountain Hemlock Zone of southwestern British Columbia for planning purposes; to assign capability ratings to land based on the biogeoclimatic characteristics of the plant associations and on the criteria for rating the limitation of land for recreational activities; and to illustrate how the capability ratings of plant associations for recreation can be used in recreation planning. This study is a response to the need for a simple, rapid, accurate, inexpensive, site specific approach to land use planning based on readily recognizable indicators. By identifying and mapping plant associations, a recreational land use capability distribution is made apparent. With such detailed site specificity, planners and natural resource managers can make rational decisions about land use based on the biogeoclimatic characteristics of plant associations and on the limitations of land for recreational activities. It is suggested that the land use planning approach presented in this thesis can be extended not only to other biogeoclimatic zones besides the Subalpine Mountain Hemlock Zone but also to other activities besides recreation. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

Where timber production is the primary management objective, knowledge of the relationship between the potential productivity of candidate tree species and levels of light, heat, nutrient, moisture and aeration is necessary for species- and site-specific decision making. For example, foresters need to decide which tree species to regenerate on a particular harvested area to obtain maximum sustainable productivity. Similarily, when considering the application of silvicultural treatments such as spacing or fertilizing, foresters need to determine whether the potential productivity of a particular site warrants the cost of the treatment. We used the site index (height of dominant trees at breast height age) of western redcedar (Thuja plicata Donn. ex D. Don.) as a measure of productivity, and described the pattern of mean site index in relation to field identified soil moisure and soil nutrient regimes.

Thesis (M.S.)--Oregon State University, 1995. / Typescript (photocopy). Includes bibliographical references (leaves 50-58). Also available on the World Wide Web.

Graduate

Diminishing virgin timber on the Coast of British Columbia leads to consideration as to how management of the second-growth forests will supply the timber industry with a sufficient quantity of good quality raw material in the future. One of the possibilities would be intensive forest management supported by thinnings. The stands of western hemlock (Tsuga heterophylla (Rafn.) Sarg.), which comprise the largest area on the Coast, may be suited to this treatment because of their advantageous silvicultural characteristics. Little information exists on proper methods of thinning these hemlock stands. In addition, experience in logging methods and means of economically handling small logs are lacking. Among the few experiments which have been established to study thinning of hemlock, one is located on East Thurlow Island where nearly pure stands of hemlock occur. The Research Forest on the Island was scheduled to become an experimental and demonstration area for the study of thinning techniques. Studies under way on that area have shown that the methods used, had limited economic success. Commercial thinning operations turned out to be unprofitable partly because there was no adequate road system available for logging. Thinning problems in general, as well as the particular aspect of thinning western hemlock and the methods of handling small logs are discussed in this thesis to illustrate the basic problems involved in a development plan for the Research Forest. Finally, this thesis presents a general road development plan for the Research Forest area and proposes a preliminary management and logging plan. Through cost analysis it is shown that the basic access road system can be constructed economically during a preparatory period by clearcutting scattered overmature stands. Subsequent thinning experiments can be based on that road network. The approach to these problems is general rather than specific because there are few detailed data available from past experiments. / Forestry, Faculty of / Graduate

Estimation of soundwood volume and value is particularly important in British Columbia because nearly half of the forests are overmature or decadent. The objective of this thesis was to develop analytical techniques to define distribution of gross and net volumes within individual standing trees in order that appropriate reductions for decay could be made for estimates of volumes of logs of specified sizes and grades. Relationships of heartrot to stand and tree characteristics and to external abnormalities were analysed for 369 western hemlock (Tsuga heterophylla (Rafn.) Sarg.) trees from the Yale Public Sustained Yield Unit in British Columbia. Comprehensive sorting, correlation and regression analyses were carried out on an I. B. M. 7044 electronic computer. One multiple regression equation provided estimates of total decay volume within individual trees from DBH, total height and external indicators of decay. It had a standard error of estimated decay volume of 18.7 cubic feet (19.5 per cent). A second equation estimated decay volume within individual logs in standing trees from the above variables and from section height. It had standard errors of estimate ranging from 13.7 cubic feet (31.6 per cent) in butt logs to 0.1 cubic feet (2.9 per cent) in top logs. The best taper function which could be derived to estimate upper stem diameters inside bark had a standard error of estimate of 1.29 inches using measures of DBH and total height. Combination of the log and tree decay estimating functions and the taper function facilitated complete description of the soundwood volumes in the sample of 369 trees. A graphical analysis was developed whereby percentages of trees in a stand with more or less than specified decay volumes could be estimated. Preliminary chemical studies of western hemlock wood infected with Echinodontium tinetorium E. and E. indicated that cellulose yields were slightly less than those from soundwood. Such partly decayed wood might be used for the manufacture of pulp without serious reductions in yield on a volume or weight basis. Further research is needed to substantiate the possible cyclic nature of decay losses and to determine the influence of bark thickness and natural pruning on the distribution of decay within individual trees. Application of the analytical techniques developed for western hemlock to other species should result in more precise estimates of soundwood volumes and values, thereby contributing to improved management planning and utilization. / Forestry, Faculty of / Graduate

Two dormancy induction trials were conducted in a private container nursery in Saanichton, British Columbia. The first study examined the effects of photoperiod induced dormancy on morphology, root growth and field performance of fall planted western hemlock (Tsuga heterophyl_1ji (Raf.)Sarg.) and Douglas-fir (Pseudotsuga menzi_esv[ (Mirb.) Franco) seedlings. Various periods of eight hour days, ranging from two to eight weeks, were applied throughout July and August 1983. Outplanting was done in late September. Survival and growth were assessed one year later. The second project investigated the effectiveness of short days, varying levels of moisture stress and a combination of both as dormancy induction techniques for Douglas-fir seedlings. The short day treatment was four weeks of eight hour days. Four levels of predawn moisture stress were: -5, -10, -15 and -25 bars. These classes respectively corresponded to control, light, medium and severe moisture stress levels. Short days and moisture stress were also combined whereby the four week period of short days followed the moisture stress treatments. These induction treatments were applied in July and August 1984. All seedlings were lifted in January 1985 and placed into cold storage for five weeks until March 1985. Morphology, root growth capacity, frost hardiness and dormancy intensity were assessed in January. Root growth capacity and dormancy intensity were again measured in March. In Study I, short days quickly initiated homogeneous budset in both species in approximately three weeks. The average height increment after treatment initiation was 3.7 cm in Douglas-fir and 4.2 cm in western hemlock. Short days reduced shoot dry weight and height. Caliper and root dry weight were unaffected. In September a surge in root growth occurred in hemlock seedlings treated with six or eight weeks of short days. The importance of early budset to allow increased root growth prior to a fall lift was demonstrated. Root growth capacity was similar among all treatments for both species. The planting survival of western hemlock seedlings increased with increasing weeks of short days. Control plants had 76% survival while the eight week regime had 91%. Survival was similar for all treated Douglas-fir seedlings. It ranged from 89% in the two week interval to 98% in the four week regime. One year height increment was significantly greater in the six and eight week short day treatments for both species. For hemlock, it ranged from 6.1 cm in the control plants to 10.4 cm in the six week trees. Douglas-fir height increment ranged from 6.4 cm for the control interval to 8.6 cm in the eight week regime. The six and eight week photoregimes produced the best quality hemlock seedlings for this study. Four weeks of short days appeared adequate for Douglas-fir. In Study II short days effectively initiated and maintained budset in Douglas-fir seedlings in four weeks. After six weeks from treatment initiation, a light to severe moisture stress was as effective in controlling height growth. A natural photoperiod with no moisture stress was least effective. In a comparison of all treatment combinations, only the control plants under a natural photoperiod were significantly larger in all morphological properties. Short days, moisture stress or a combination of both had similar effects on reducing height, caliper, shoot dry weight and root dry weight. Unstressed seedlings in a natural daylength had the highest value of root growth capacity. All other treatment combinations had significantly lower root growth capacity. Only the severe stress under a natural photoperiod significantly reduced root growth capacity compared to any other treatment. Short days accelerated bud burst in the January and March dormancy intensity tests. Frost hardiness was similar among all treatments. Selection of a regime which controlled height growth while maintaining seedling quality was not clearcut. A short photoperiod with no moisture stress was most effective in initiating budset. However, few morphological and physiological differences were evident between short day plants and light and medium stressed seedlings. / Forestry, Faculty of / Graduate