FERTILIZATION AT T IME OF SOWING AND AT T IME OF PLANTING1

Canadian Journal of Forest Research, 2002

Four rates of N (0, 50, 100, and 150 kg·ha -1 ) with and without a fertilizer mix containing P, K, S, Ca, Mg, and micronutrients were applied to a stand of 8-year-old lodgepole pine (Pinus contorta var. latifolia Engelm.) in four applications during 7 years. Fourteen years after the first fertilization, mean tree basal area and volume were significantly increased in the treatments containing the two highest rates of N plus the fertilizer mix. Mean tree basal area was 38% greater and mean tree volume was 42% greater in the highest N (525 kg·ha -1 ) plus mix treatment than in the control treatment. Stand basal area increased 48% over the control in the highest N plus mix treatment. Mean tree basal area and volume were 27 and 25% greater than the control under the intermediate N rate (350 kg·ha -1 ) with mix, respectively. Height growth was not significantly increased by fertilization. Both higher rates of N (four applications of >100 kg·ha -1 ) and the fertilizer mix were required for significant growth responses to occur. Addition of N alone or mix alone had a negative effect on mean tree basal area and volume. Addition of higher N rates without the mix decreased foliar total S and SO 4 -S concentration and increased the N/S ratio. Addition of the higher rates of N without the mix aggravated slight K deficiencies. The responses to the higher N rates in combination with the fertilizer mix are mainly attributable to S.

2018

Fertilization and vegetation control are two useful silvicultural tools available to forest managers. Fertilization directly adds nutrients, and vegetation control indirectly improves nutrient and water availability to the crop species. In young pine stands that have not fully captured the site, there has been concern that adding fertilizer will stimulate competing vegetation, which will then outcompete the pines and result in slower pine growth. To determine if this is a valid concern, we tested the hypothesis that there is no difference in pine growth in young stands when applying fertilizer alone or with vegetation control. We installed two treatments at 11 sites with two replications at each site in pine stands across the Southeastern United States. Treatments were fertilization (120 and 12 pounds per acre of elemental nitrogen and phosphorus, respectively, applied every 2 years) and fertilization plus complete sustained vegetation control. Other elements were added if foliar nu...

The interaction of nursery fertilization and field fertilization at the time of planting on survival, growth and frost heaving of container seedlings of birch (Betula pubescens) and Sitka spruce (Picea sitchensis) was tested in a factorial trial on four sites in Iceland. A trial with nutrient loading of seedlings was done during a four week period in May-June in a nursery prior to planting. Seedlings were divided into three groups and irrigated twice weekly for four weeks with; control = pure water; Sc1 = 10 g fertilizer m -3 water and Sc2 = 20 g m -3 . Field experiments were established on two sites in east Iceland and two in west Iceland. On each site the three nursery treatments were split up by giving the seedlings either a single application of 15 g seedlings -1 of the fertilizer "Gróska II" or no fertilizer. The pre-treatments Sc1 and Sc2 increased the shoot growth signi-ficantly during the first summer, and this effect was still seen on the volume growth three years...

2007

The article documents the fertilization effects on the plantation of Grand fir in the area of the Czech_Moravian Highland (ar eaŽd'árské vrchy), on ýpical poor sites (forest site group 5Kacid fir-beech site). The plantations were sfudied at the age of 7_16 years. The forest stands belong to the estate Lesy Dr. Radslava Kinského, they are located in the altitude 580 m a.s.l', the site is characterized by the forest type 5K8 and soil type Dystric Cambisol. As the amelioration matter is concemed, the slow-release fertilizer SILVAMXo was used in the tabletted as well as powdered form. Despite relatively low amount of nutrients applied, the plantations showed considerable increment effect in the case ofboth fertilizer forms. On these poor sites, the favorable fertilization effects can be expected by introducing and reintroducing of more site-demanding tree speciesjncluding the species studied.

Canadian Journal of Forest Research, 2005

We investigated the effects of repeated fertilization (either periodically every 6 years or annual fertilization) on needle longevity and growth response in two juvenile lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) stands in the interior of British Columbia, Canada. Annual fertilization decreased needle longevity by 23% at the Kenneth Creek site and by 30% at Sheridan Creek, compared with the control treatments at each site. At Sheridan, repeated fertilization significantly increased effective leaf area index, foliated shoot length, and annual shoot growth. However, none of these variables was significantly altered by repeated fertilization at Kenneth. At both locations, fertilization elevated nutrient concentrations in the current year's foliage. Annual fertilization increased nitrogen concentration in mid-crown branches of retained cohorts (1998–2002) at both study sites. Furthermore, annual nitrogen addition apparently induced or exacerbated copper and iron d...

Forest Ecology and Management, 2014

Recent investigations have shown that annual wood production in Sweden can be increased by 30 million m 3 per year in a long-term perspective (>50 years) by using new forest management methods such as new tree species or seedling materials. However, to meet the increased demands during the next 20 years, Sweden will have to rely on silvicultural methods available today. Growth in boreal and cold temperate forest is with only few exceptions limited by nutrients availability, primarily nitrogen, and one way to satisfy the increased demands in a short-term perspective is nitrogen fertilization. A set of thinning and fertilization experiments were started in the 1960's in Scots pine and Norway spruce stands over the whole of Sweden representing different soil, moisture and vegetation types. We used data from these experiments to examine the long-term effects of repeated fertilization in thinned stands on growth, stand development, and yield. The 34 Scots pine sites and 13 Norway spruce sites included in our analyses had at least four treatment plots (no thinning, repeated light thinnings, repeated light thinnings with repeated N fertilization, and repeated light thinnings with repeated N + P fertilization). In northern Sweden, 100 kg N ha À1 and 150 kg N ha À1 were applied at each fertilization event for Scots pine and Norway spruce stands, respectively. In southern Sweden, 150 kg ha À1 N was applied in Scots pine stands and 200 kg ha À1 N in Norway spruce stands. Phosphorus was applied at the rate of 100 kg ha À1 . Several sites also included non-thinned fertilized plots. Pine stands but not spruce stands were responsive (up to 25% more growth depending of the attribute assessed) to repeated fertilization. Surprisingly, the non-thinned pine stands showed strong continuing response to fertilization throughout the 30+ year observation period resulting in higher cumulative volume response than the thinned stands. In thinned stands incremental volume response to fertilization continued but slowly diminished with time indicating that fertilization and thinning effects were less than additive. However, thinning and fertilization effects were additive for diameter growth. Fertilization accelerated stand development with significant shifts in diameter distributions to larger and potentially more valuable trees. Conclusively, repeated nitrogen fertilization is a silvicultural practice that will result in significant and sustained increases in Scots pine production.

Dean S. DeBell is a research forester (retired), Constance A. Harrington is a research forester, and John Shumway is a research soil scientist (retired), Forestry Sciences Laboratory, 3625 93 Three thinning treatments (thinned to 3.7 by 3.7 m, thinned to 4.3 by 4.3 m, and an unthinned control treatment with nominal spacing averaging 2.6 by 2.6 m) were installed in a 10-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation growing on a low-quality site at the Wind River Experimental Forest in southwest Washington. Two years after thinning, two fertilizer treatments were superimposed on the design (0 and 224 kg per ha of nitrogen applied as ammonium nitrate). Diameter growth increased with increasing spacing throughout the 6-year study period, and it was also increased by fertilizer in both the thinned and unthinned (control) treatments. Thinning shock, a reduction in height growth after thinning, was expected at this study site because severe thinning shock had been documented in earlier nearby trials. Height growth was initially reduced slightly by thinning, but by the third 2-year period after thinning, height growth in thinned, unfertilized treatments was equal to or greater than height growth in the unthinned, unfertilized treatment. Fertilizer application increased height growth on average by 13 percent in the first 2 years after fertilization. In the third and fourth years after fertilization, however, fertilizer increased average height growth by 9 percent, but the increase was substantial (16 percent) only in the unthinned control treatment. The mild, ephemeral nature of thinning shock in our study was in contrast to the severe, long-lasting shock in earlier studies at Wind River. The milder shock in our study could be related to one or more of the following: (1) thinning was done at an early age, (2) impacts of fire (natural or prescribed) preceding planting were minor, and (3) seed source of the planted stock was appropriate for the location. Based on comparisons with other studies at Wind River and elsewhere, we suspect that use of nonlocal, maladapted seed sources in the earlier studies may have predisposed those trees to thinning shock. Furthermore, we suspect that the much higher responses to fertilizer application reported in the earlier studies may be associated with intense natural fires prior to planting, and the reduced nutritional status of those sites may have been further exacerbated by the use of maladapted seed sources.

International Journal of Forestry Research, 2012

Fertilization of conifers often results in highly variable growth responses across sites which are difficult to predict. The goal of this study was to predict the growth response of lodgepole pine (Pinus contorta var. latifolia) crop trees to thinning and fertilization using basic site and foliar characteristics. Fifteen harvest-origin stands along the foothills of the Rocky Mountains of Alberta were subjected to six treatments including two levels of thinning (thinning to 2500 stems per hectare and a control) and three types of fertilization (nitrogen-only fertilization, complete fertilization including nitrogen with added P, K, S, Mg, and B, and no fertilization). After three growing seasons, the growth response and foliar status of the crop trees were examined and this response was related to site and foliar characteristics. There was a small and highly variable additive response to fertilization and thinning; diameter growth of crop trees increased relative to the controls an average of 0.3 cm with thinning, 0.3 cm with either N-only or complete fertilization and 0.6 cm when thinned and fertilized. The increase in diameter growth with thinning and nitrogen-only fertilization was positively related to site index but not to any other site factors or pretreatment foliar variables such as nutrient concentrations, ratios, or thresholds.

Canadian Journal of Forest Research

Wood properties and growth were measured on breast-height cores and on disks collected at different heights from a thinned and fertilized midrotation loblolly pine (Pinus taeda L.) plantation in the lower Coastal Plain of North Carolina. The study was laid out in a randomized complete-block design receiving four levels of nitrogen (N) fertilizer: unfertilized control and 112, 224, and 336 kg/ha plus 28 kg/ha of phosphorus with each treatment. The effect of fertilization was analyzed for the whole-disk and for a 4 year average following fertilization on data collected from breast-height cores and from disks. The fertilization treatments did not significantly affect whole-disk wood properties but significantly increased radial growth. Fertilization rate of 336 kg/ha N significantly reduced 4 year average ring specific gravity and latewood specific gravity. Wood properties of trees that received 112 and 224 kg/ha N were not affected following treatment. There was no height related tren...