Different nitrogen sources for fertilizing western hemlock in western Washington

1984 ◽  
Vol 14 (2) ◽  
pp. 155-162 ◽  
Author(s):  
M. A. Radwan ◽  
D. S. DeBell ◽  
S. R. Webster ◽  
S. P. Gessel
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Volume Growth ◽  
Basal Area ◽  
N Fertilization ◽  
Height Growth ◽  
Growth Responses ◽  
Total N ◽  
Area Growth ◽  
Western Washington

Effects of different sources of fertilizer N on selected chemical characteristics of soils and foliage, and on growth of western hemlock (Tsugaheterophylla (Raf.) Sarg.) were compared at three different sites in western Washington. Treatments were the following: untreated control (O), ammonium nitrate (AN), ammonium sulfate (AS), calcium nitrate (CN), urea (U), and urea – ammonium sulfate (US). Fertilizers were applied in the spring (April–May) at 224 kg N/ha. Forest floor and mineral soil, to a depth of 5 cm, and foliage were sampled periodically for 2 years. Height and diameter of selected trees were measured periodically for 4 years. Results are reported mostly for two sites, one in the Cascade Range and one in the coastal zone in western Washington. The pH of forest floor and mineral soil varied by treatment, and the two urea fertilizers caused substantial initial rise. Effects on soil and foliar nutrients varied by fertilizer, sampling date, and location. In general, all fertilizers increased NH4 N, N03 N, and total N in the forest floor and mineral soil, and total N in the foliage. Also, with some exceptions, especially with foliar P in the Cascade site, fertilization reduced foliar content of important nutrients. At the Cascade site, 4-year growth responses in height, basal area, and volume averaged over all fertilizers were 30, 34, and 32%, respectively. AN, AS, CN, and urea resulted in height growth significantly (P < 0.20) higher than that of the control. Significant basal area growth and volume-growth responses were produced by AN, CN, and US. No significant height-growth response to any fertilizer occurred in the coastal stand; basal area growth and volume-growth responses averaged 27 and 21%, respectively, and best response occurred with urea. These results suggest that the low and inconsistent response of hemlock to N fertilization cannot be improved by applying some N fertilizer other than urea. Factors limiting response to N fertilization may be associated with availability of native N and other nutrients or other characteristics of hemlock sites and stands.

Growth response of young, thinned Douglas-fir stands to nitrogen fertilizer in relation to soil properties and tree nutrition

1994 ◽  
Vol 24 (8) ◽  
pp. 1684-1688 ◽  
Author(s):  
P. Hopmans ◽  
H.N. Chappell
Keyword(s):  
Basal Area ◽  
N Fertilization ◽  
Douglas Fir ◽  
Relative Volume ◽  
Strongly Correlated ◽  
Growth Responses ◽  
Total N ◽  
Soil Variables ◽  
Volume Increment ◽  
Area And Volume

Application of 224 kg N/ha to young, thinned stands of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) at 35 sites in western Oregon and Washington significantly increased basal area and volume increment over 8 years following treatment. However, response varied considerably between sites, and relative volume increment exceeded 10% at only 19 of the 35 sites. Response to applied N was evaluated in relation to forest floor and soil variables as well as to levels of N in foliage. Relative responses in basal area and volume were significantly correlated with total N concentration and the C/N ratio of the soil. However, these relationships explained only part (18–22%) of the observed variation in response. In contrast, relative response was strongly correlated with the level of N in the foliage of nonfertilized trees at 11 sites, accounting for 94% of the variation between sites. Use of foliar N data clearly has potential to predict growth responses to N fertilization of young thinned Douglas-fir stands, although further work is needed to test the relationship for a wider range of sites and stands.

Initial quantitative characterization of soil nutrient regimes. I. Soil properties

1987 ◽  
Vol 17 (12) ◽  
pp. 1557-1564 ◽  
Author(s):  
R. D. Kabzems ◽  
K. Klinka
Keyword(s):  
Soil Properties ◽  
Forest Floor ◽  
Mineral Soil ◽  
Soil Nutrient ◽  
N Fertilization ◽  
Total N ◽  
Quantitative Classification ◽  
Topographic Features ◽  
Exchangeable Ca ◽  
Study Sites

Previous attempts to characterize soil nutrient regimes of forest ecosystems have been qualitative evaluations utilizing vegetation and (or) topographic features, morphological soil properties, and mineralogy of soil parent materials. The objective of this study was to describe and provide initial data for quantitative classification of soil nutrient regimes in some Douglas-fir ecosystems on southern Vancouver Island. A multivariate classification using forest floor plus mineral soil mineralizable N and exchangeable Mg quantities was proposed for the four nutrient regimes (poor, medium, rich, and very rich) recognized in this study. Significant differences in mineralizable and total N existed between the four identified soil nutrient regimes. The previous N fertilization of two study sites did not seem to change soil N status sufficiently to alter the classification. The differences in nutrient availability were more distinct when forest floor and mineral soil properties, expressed on an areal basis, were summed. There were no significant differences in exchangeable Ca and Mg for the poor and medium soil nutrient regimes. The humus form of the forest floor was an important characteristic for identifying soil nutrient regimes in the field; however, the nutrient quantities of the forest floor reflected differences in bulk density and depth and did not effectively distinguish between regimes.

Foliage and stand growth responses of semimature lodgepole pine to thinning and fertilization

1998 ◽  
Vol 28 (12) ◽  
pp. 1794-1804 ◽  
Author(s):  
Richard C Yang
Keyword(s):  
Pinus Contorta ◽  
Tree Mortality ◽  
Lodgepole Pine ◽  
Volume Growth ◽  
Basal Area ◽  
Dry Mass ◽  
N Fertilization ◽  
Growth Responses ◽  
Fascicle Length ◽  
Stand Growth

The aim of this study was to quantify the interactive response of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) to thinning and nitrogen (N) fertilization in midrotation stands by assessing foliar and stand growth response relationships and determining the optimum fertilizer regime. The experiment design was a factorial arrangement of treatments with two thinning intensities (thinned and unthinned control) and four N levels (0, 180, 360, and 540 kg·ha-1). Foliage was sampled annually from trees in buffers for 4 years following treatment and plot trees measured at a 5-year interval. Results indicated that the effect of fertilization on fascicle length and needle dry mass disappeared 2 years after N treatment, while thinning effects on foliage emerged 3 years after fertilization. Both first year fascicle length and dry mass were reliable predictors (r2 = 0.87 and 0.82, respectively) of subsequent stand volume growth. Applications of N at 360 kg·ha-1 to thinned and unthinned plots, respectively, improved 10-year periodic height increment by 20 and 19%, diameter at breast height by 29 and 34%, basal area by 21 and 36%, and total volume by 25 and 28%. Fertilization of N at this level appears to be optimal based on foliar and mensurational responses. High N loadings increased tree mortality and accelerated stand development and so it could be advantageously used as a tool for managing overstocked stands.

scholarly journals Growth of Young Douglas-Fir Plantations Across a Gradient in Swiss Needle Cast Severity

2002 ◽  
Vol 17 (2) ◽  
pp. 86-95 ◽  
Author(s):  
Douglas A. Maguire ◽  
Alan Kanaskie ◽  
William Voelker ◽  
Randy Johnson ◽  
Greg Johnson
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Height Growth ◽  
Douglas Fir ◽  
Site Quality ◽  
North Coast ◽  
Needle Cast ◽  
Basal Area Growth ◽  
Area Growth ◽  
Swiss Needle Cast

Abstract During the past decade, Swiss needle cast (SNC) damage has intensified in many Douglas-fir plantations in the Coast Range of Oregon, particularly along the immediate north coast. In plantations with severe symptoms, growth losses and reduced tree vigor are evident, but the magnitude of growth losses associated with varying intensities of damage is not known. A growth impact study was conducted in 1997 to quantify retrospectively the relationship between growth losses and visual symptoms in 10- to 30-yr-old Douglas-fir plantations in coastal northwestern Oregon, a population totaling 75,700 ha. A random sample of 70 Douglas-fir plantations was selected from the population and evaluated for Swiss needle cast severity. One 0.02 ha plot was destructively sampled in each plantation to reconstruct past height and basal area growth trends and to characterize foliage loss and distribution. The SNC “effect” was assessed by comparing growth of plantations with varying degrees of Swiss needle cast to growth of those that retained maximal amounts of foliage, after correcting for initial stand density, Douglas-fir growing stock, age, and site index. Of numerous possible SNC indices, mean needle retention (yr) explained the largest amount of variation in both basal area and top height growth. Prior to 1990, top height growth was similar across all plantations after correcting for site quality and plantation age; but, by 1992, top height growth losses appeared and were proportional to apparent foliage losses. In 1996, top height growth was reduced by up to 25% relative to plantations with little or no SNC. Basal area growth reductions began to appear around 1990, and in 1996 basal area growth of the most heavily damaged plantations was 35% less than the growth that would be expected in absence of SNC damage. The inferred volume growth loss for 1996 averaged 23% for the 75,700 ha target population, but this loss averaged as high as 52% for the most severely impacted plantations. West. J. Appl. For. 17(2):86ߝ95.

scholarly journals Contrasting conifer species productivity in relation to soil carbon, nitrogen and phosphorus stoichiometry of British Columbia perhumid rainforests

2020 ◽  
Vol 17 (5) ◽  
pp. 1247-1260
Author(s):  
John Marty Kranabetter ◽  
Ariana Sholinder ◽  
Louise de Montigny
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Basal Area ◽  
Picea Sitchensis ◽  
P Availability ◽  
Growth Responses ◽  
Conifer Species ◽  
Effective Measure ◽  
Element Ratios ◽  
Wide Range

Abstract. Temperate rainforest soils of the Pacific Northwest are often carbon (C) rich and encompass a wide range of fertility, reflecting varying nitrogen (N) and phosphorus (P) availability. Soil resource stoichiometry (C : N : P) may provide an effective measure of site nutrient status and help refine species-dependent patterns in forest productivity across edaphic gradients. We determined mineral soil and forest floor nutrient concentrations across very wet (perhumid) rainforest sites of southwestern Vancouver Island (Canada) and employed soil element ratios as covariates in a long-term planting density trial to test their utility in defining basal area growth response of four conifer species. There were strong positive correlations in mineral soil C, N, and organic P (Po) concentrations and close alignment in C : N and C : Po both among and between substrates. Stand basal area after 5 decades was best reflected by mineral soil and forest floor C : N, but in either case included a significant species–soil interaction. The conifers with ectomycorrhizal fungi had diverging growth responses displaying either competitive (Picea sitchensis) or stress-tolerant (Tsuga heterophylla, Pseudotsuga menziesii) attributes, in contrast to a more generalist response by an arbuscular mycorrhizal tree (Thuja plicata). Despite the consistent patterns in organic matter quality, we found no evidence for increased foliar P concentrations with declining element ratios (C : Po or C : Ptotal) as we did for N. The often high C : Po ratios (as much as 3000) of these soils may reflect a stronger immobilization sink for P than N, which, along with ongoing sorption of PO4-, could limit the utility of C : Po or N : Po to adequately reflect P supply. The dynamics and availability of soil P to trees, particularly as Po, deserves greater attention, as many perhumid rainforests were co-limited by N and P, or, in some stands, possibly P alone.

Effects of Crown Thinning on Baldcypress Height, Diameter, and Volume Growth

1988 ◽  
Vol 12 (4) ◽  
pp. 252-256 ◽  
Author(s):  
Stephen G. Dicke ◽  
John R. Toliver
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Height Growth ◽  
Taxodium Distichum ◽  
Volume Increment ◽  
Crown Thinning ◽  
Epicormic Branching

Abstract Crown thinning a 63-year-old stand of baldcypress (Taxodium distichum [L.] Rich.) averaging 220 ft²/ac of basal area to 180, 140, and 100 ft²/ac resulted in 5-year diameter growths of 0.44, 0.51, and 0.77 in., respectively. The unthinned control was significantly less at 0.31 in. Six-year height growth averaged 3.1 ft and was not influenced by treatment. Thinning to 140 and 100 ft²/ac stimulated epicormic branching on many trees, which may lower log quality. All crown thinning treatments appeared to increase sawtimber volume increment and sawtimber volume/ac over the control 5 years after thinning. South. J. Appl. For. 12(4):252-256.

Fertilization of Established Southern Pine Stands: Effects of Single and Split Nitrogen Treatments

1993 ◽  
Vol 17 (3) ◽  
pp. 135-138 ◽  
Author(s):  
Eric J. Jokela ◽  
Stephen C. Stearns-Smith
Keyword(s):  
Loblolly Pine ◽  
Volume Growth ◽  
Basal Area ◽  
Pinus Elliottii ◽  
Growth Responses ◽  
Southern Pine ◽  
N Application ◽  
Pine Stands ◽  
Pinus Taeda L ◽  
Nitrogen Treatments

Abstract Data from six fertilizer trials established in semimature southern pine stands (five slash pine, Pinus elliottii Engelm. var. elliottii; one loblolly pine, Pinus taeda L.) were analyzed to determine the efficacy of single vs. split fertilizer treatments. Both fertilizer treatments supplied an elemental equivalent of 200 lb nitrogen (N)/ac and 50 lb phosphorus (P)/ac; however, the first treatment was delivered as a single dose, and the second treatment was a split N application (i.e., 50 lb N and 50 lb P/ac (initial); 150 lb N/ac (2 yr later). Cumulative responses of fertilized plots were still significantly greater than the controls in five trials after 8 yr and averaged 43% (15.7 ft²/ac) and 39% (607 ft³/ac) for basal area and stand volume growth, respectively. In general, no significant differences in either the magnitude or duration of response were detected between the single and split N fertilizer treatments. This suggests that delaying a portion of the N application for 2 yr will not diminish the level of growth responses attained. Therefore, land managers have flexibility in using either application method when implementing midrotation fertilizer prescriptions. South. J. Appl. For. 17(3):135-138.

scholarly journals A meta-analysis on the impacts of partial cutting on forest structure and carbon storage

2013 ◽  
Vol 10 (6) ◽  
pp. 3691-3703 ◽  
Author(s):  
D. Zhou ◽  
S. Q. Zhao ◽  
S. Liu ◽  
J. Oeding
Keyword(s):  
Forest Structure ◽  
Forest Floor ◽  
Recovery Time ◽  
Mineral Soil ◽  
Basal Area ◽  
Partial Cutting ◽  
C Storage ◽  
Cutting Intensity ◽  
Stand Basal Area ◽  
Area And Volume

Abstract. Partial cutting, which removes some individual trees from a forest, is one of the major and widespread forest management practices that can significantly alter both forest structure and carbon (C) storage. Using 748 observations from 81 studies published between 1973 and 2011, we synthesized the impacts of partial cutting on three variables associated with forest structure (mean annual growth of diameter at breast height (DBH), stand basal area, and volume) and four variables related to various C stock components (aboveground biomass C (AGBC), understory C, forest floor C, and mineral soil C). Results show that the growth of DBH increased by 111.9% after partial cutting, compared to the uncut control, with a 95% bootstrapped confidence interval ranging from 92.2 to 135.9%, while stand basal area and volume decreased immediately by 34.2% ([−37.4%, −31.2%]) and 28.4% ([−32.0%, −25.1%]), respectively. On average, partial cutting reduced AGBC by 43.4% ([−47.7%, −39.3%]), increased understory C storage by 391.5% ([220.0%, 603.8%]), but did not show significant effects on C stocks on forest floor and in mineral soil. All the effects, if significant (i.e., on DBH growth, stand basal area, volume, and AGBC), intensified linearly with cutting intensity and decreased linearly over time. Overall, cutting intensity had more strong impacts than the length of recovery time on the responses of those variables to partial cutting. Besides the significant influence of cutting intensity and recovery time, other factors such as climate zone and forest type also affected forest responses to partial cutting. For example, a large fraction of the changes in DBH growth remains unexplained, suggesting the factors not included in the analysis may play a major role. The data assembled in this synthesis were not sufficient to determine how long it would take for a complete recovery after cutting because long-term experiments were scarce. Future efforts should be tailored to increase the duration of the experiments and balance geographic locations of field studies.

Basal Area and Volume Development of Natural Even-Aged Shortleaf Pine Stands in the Ouachita Mountains

1992 ◽  
Vol 16 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Paul A. Murphy ◽  
Edwin R. Lawson ◽  
Thomas B. Lynch
Keyword(s):  
Initial Conditions ◽  
Volume Growth ◽  
Basal Area ◽  
Pinus Echinata ◽  
Shortleaf Pine ◽  
Ouachita Mountains ◽  
Annual Increment ◽  
Basal Area Growth ◽  
Area Growth ◽  
Mean Annual Increment

Abstract Shortleaf pine (Pinus echinata Mill.) stands, average age 41 years, were thinned to different density levels (45 to 125 ft² of basal area in increments of 20 ft²). The stands received no further thinning. Equations for projected volumes and basal area per acre given initial conditions were formulated and fitted. The following trends were observed using the equations. Over a 24-year period, total basal area growth per acre started out over 2 ft² and had declined to less than 2 ft² by the end. Annual basal area growth had already culminated by age 41. Total annual cubic-foot volume growth per acre depended largely on initial stocking. The initial stocking and subsequent growth of the sawtimber portion were not related to the thinning treatments. Although sawtimber periodic annual cubic-foot growth culminated during the period under study, board-foot growth did not, indicating that mean annual increment for board-foot volumes had not culminated by age 64. South. J. Appl. For. 16(1):30-34.

Selection Management of Shortleaf Pine in the Ouachita Mountains

1991 ◽  
Vol 15 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Paul A. Murphy ◽  
James B. Baker ◽  
Edwin R. Lawson
Keyword(s):  
Stand Structure ◽  
Volume Growth ◽  
Basal Area ◽  
Pinus Echinata ◽  
Q Value ◽  
Shortleaf Pine ◽  
Ouachita Mountains ◽  
Tree Diameter ◽  
Area Growth ◽  
Experimental Watersheds

Abstract Selection (uneven-aged) management was instituted in shortleaf pine (Pinus echinata Mill.) stands on three experimental watersheds in the Ouachita Mountains. The residual stand structure imposed on each was 60 ft² of basal area, a maximum tree diameter of 18 in., and a q value of 1.2 for 1 in. dbh classes. Hardwoods were injected with herbicide before the initial harvest. The average annual per-acre growth for the three watersheds for the first 6-year management period was 2 ft² of merchantable basal area growth, 57 ft³ of merchantable volume growth, and sawtimber growth of 157 board feet for the Doyle rule, 231 bd ft for the Scribner rule, and 274 bd ft for the International ¼-inch rule. Basal area and merchantable volume growth were up to expectations, but sawtimber growth was not. Sawtimber growth may increase as stand structure improves under management. South J. Appl. For. 15(1):61-67.

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