Summarizes results obtained from 33 lodgepole pine fertilization research installations established at the Kalamalka Forestry Centre in Vernon, British Columbia. Most of the research was conducted in 15- to 35-year-old thinned, fire-origin stands in the montane spruce and sub-boreal spruce biogeoclimatic zones. Results are discussed with regard to such research topics as: pre- and post-fertilization foliar nutrient status; response to nitrogen additions; effects of nitrogen application rate; effects of post-thinning stand density and site index; effects of timing of fertilization and thinning; small-mammal damage; and effects of snow accumulation.
Widespread sulphur (S) deficiencies have been detected in lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) stands in the Sub-Boreal Spruce biogeoclimatic zone of central interior British Columbia. Field experiments in this region have shown that addition of sulphate-S to nitrogen (N) fertilization treatments rapidly increases foliar S concentrations, and usually improves tree growth responses relative to N-only treatments. However, there is an insufficient scientific basis for choosing this S form over more slowly available elemental S-based fertilizers. To address this knowledge gap, this study was begun in 2001 to compare the behaviour of sulphate-S and elemental-S fertilizers in an area-based fertilizer trial, using stable isotope tracer methods to examine the fate and transformations of fertilizer S. Fertilizer treatments were applied to two lodgepole pine stands, near Fraser Lake (Holy Cross site) and in the Bowron River valley (Kenneth Creek site), in fall 2002. This establishment report reviews background literature relevant to this study, details the experimental design and methods used, and documents the initial soil and stand conditions at the time the experimental treatments were installed. ?Pre-treatment analyses indicated that mineral soils at these sites have low total S concentrations, which are typical of the British Columbia central interior and are among the lowest reported in the temperate and boreal zones worldwide. Concentrations of other total and (or) available soil macronutrients (N, Ca, Mg, K, P) were usually higher at the Holy Cross site than at the Kenneth Creek site. Lodgepole pine foliar analyses indicated that S deficiency was more pronounced at the former site. Ratios of background S stable isotopes in lodgepole pine foliage and soils differed sufficiently from those of the applied S fertilizers to make a tracer experiment feasible.
Topics include the resource, physiology and genetics, site classification, factors Influencing productivities, regeneration, management, harvest and utilization of the most widely distributed conifer in western North America.
"The effects of fertilization with nitrogen (N) alone, and in combination with sulphur (S), on the growth and foliar nutrition of six immature, managed Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn.] Franco) stands in the Interior Cedar-Hemlock (ICH) biogeoclimatic zone of British Columbia are reported 6 years after treatment. Results indicate that interior Douglas-fir stands growing on circummesic sites within the ICH zone are generally responsive to fertilization. Disregarding results from one installation that was damaged by Armillaria root disease, average net volume response following fertilization with N alone was 13.5 m3/ha (range: 6.5-24 m3/ha) compared to the control treatment. Six-year volume gains from N+S additions averaged 16 m3/ha (range: 10-23 m3/ha). In relative terms, stand volume responses to fertilization with N and N+S averaged 24% (range: 8-41%) and 28% (range: 16-39%), respectively. Growth projections generated by the tipsy growth and yield program indicate that the accelerated stand development following a single fertilizer application will likely reduce biological rotations (i.e., culmination of mean annual increment) and technical rotations (e.g., minimum harvestable age) by 2-3 years. Relative growth responses compare favourably with results from Douglas-fir fertilization studies in other jurisdictions.??Pre- and post-fertilization foliar nutrient analyses indicate that several of the sites were marginally S deficient, and that S status deteriorated 1 year following N fertilization. Added S was readily taken up, thereby maintaining a favourable N:S balance in trees fertilized with N+S. Despite improvements in foliar S status, the incremental growth benefits of added S may be too small on most sites to justify the extra expense involved in blending and applying N+S fertilizers in large-scale aerial operations.??Results from this study, and others, indicate that pre-fertilization levels of foliar N and sulphate S (SO4) may have utility in selecting candidate stands and in making appropriate fertilizer prescriptions. For example, the largest growth responses following fertilization may be expected in stands with pre-fertilization foliar N levels less than 11.5 g/kg ( 13 g/kg when using dry combustion analytical methods). Also, low foliar N combined with small amounts of pre-fertilization foliar SO4 (
Beginning in 1992, the British Columbia Ministry of Forests established a small network of lodgepole pine and interior spruce nutrient optimization research installations on representative sites within three major biogeoclimatic (BEC) zones in the British Columbia Interior. The objectives of the long-term "maximum productivity" study are to (1) compare the effects of different regimes and frequencies of repeated fertilization on the foliar nutrition, growth, and development of young interior forests, and (2) determine the effects of large nutrient additions on above- and below-ground timber and non-timber resources. This report examines the effects of repeated fertilization on foliar nutrition and tree- and stand-level growth and development over 12 years at the five lodgepole pine study sites.--Document.
"The preliminary effects of different regimes and frequencies of repeated fertilization on foliar nutrition and growth of eight young lodgepole pine and interior spruce forests in north-central British Columbia are reported. At least 6 years of growth measurements have been obtained from seven of the eight "maximum productivity" installations. These results indicate that the repeated fertilization of young managed forests may be a potentially viable strategy for addressing timber supply challenges in the interior of British Columbia. Young spruce plantations are apparently particularly well suited to intensive forest management. Although four of the five lodgepole pine installations have produced significant growth gains following periodic (every 6 years) and yearly fertilization, the responses to date have been more variable and consistently smaller than those obtained at the spruce study sites."
