A soil-site study for inland Douglas-fir

1990 ◽  
Vol 20 (6) ◽  
pp. 686-695 ◽  
Author(s):  
Robert A. Monserud ◽  
Ula Moody ◽  
David W. Breuer
Keyword(s):  
Habitat Type ◽  
Site Index ◽  
Douglas Fir ◽  
Soil Survey ◽  
Western Montana ◽  
Disappointing Result ◽  
Site Factor ◽  
Soil Site ◽  
Northern Idaho ◽  
Factor Interactions

A soil-site study was conducted for inland Douglas-fir growing in northern Idaho and north western Montana. The hypothesis was that standard soil survey procedures would provide edaphic data that could predict site index in the absence of site trees. Soil profile descriptions and physical analyses were obtained on 133 plots, along with several physiographic site descriptors. Chemical analyses were performed on soil samples from a third of these plots, and moisture availability was determined on 60% of the plots. Site index was based on felled-tree stem analyses. Elevation was the strongest predictor, accounting for a third of the variation in site index. The addition of habitat type information resulted in a significant improvement (as did longitude and precipitation), but still left over half the variation unexplained. After examining numerous soil properties the standard error could only be reduced 0.3 m, a disappointing result in light of the considerable time and expense necessary for soil sampling. The causes of these low soil–site correlations could not be conclusively determined, but the most likely explanations are (i) that the number of important site factor interactions occurring in this large and complex study area far exceeded the sample size, and (ii) failure to measure the true causes of site productivity.

Comparison and Development of Height Growth and Site Index urves for Douglas-Fir in the Inland Northwest

1989 ◽  
Vol 4 (3) ◽  
pp. 85-88
Author(s):  
James L. Vander Ploeg ◽  
James A. Moore
Keyword(s):  
Pseudotsuga Menziesii ◽  
Model Development ◽  
Analysis Data ◽  
Site Index ◽  
Height Growth ◽  
Douglas Fir ◽  
Western Montana ◽  
Stem Analysis ◽  
Inland Northwest ◽  
Central Idaho

Abstract Stem analysis data from Douglas-fir (Pseudotsuga menziesii) collected throughout the inland Northwest were used for testing height growth and site index equations. The equations performed well in northern and central Idaho, northeast Oregon, and northeast Washington on vegetative types similar to those sampled in model development. However, if the equations were applied on drier sites outside the original geographic study area, overestimates of height growth and under-estimates of site index could result. Therefore, revised height growth and site index equations are presented for western Montana and central Washington. West. J. Appl. For. 4(3):85-88, July 1989.

Site Index and Height Growth Curves for Ponderosa Pine, Western Larch, Lodgepole Pine, and Douglas-Fir in Western Montana

1992 ◽  
Vol 7 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Kelsey S. Milner
Keyword(s):  
Ponderosa Pine ◽  
Growth Curves ◽  
Analysis Data ◽  
Site Index ◽  
Height Growth ◽  
Douglas Fir ◽  
Growth Patterns ◽  
Western Montana ◽  
Stem Analysis ◽  
Western Larch

Abstract Height growth patterns from several published site curve sytems for ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii var glauca), western larch (Larix occidentalis) and lodgepole pine (Pinus contorta var latifolia) were compared to stem analysis data from western Montana. Most of the published curves had height growth patterns that differed significantly from those in the data. The magnitude of the deviations often varied by level of site index; this appeared to be related to differences in the range of site qualities sampled. Those curves constructed from stem analysis data from geographically similar populations compared most closely. Curves constructed using guide curve techniques showed a consistent tendency to underpredict heights at greater ages. New site index and height growth curves are presented for each species. West. J. Appl. For. 7(1):9-14.

Dominant Height and Site Index Equations for Douglas-Fir and Engelmann Spruce in East-Central Arizona

1992 ◽  
Vol 7 (2) ◽  
pp. 40-44 ◽  
Author(s):  
W. F. Stansfield ◽  
J. P. McTague ◽  
R. Lacapa
Keyword(s):  
Habitat Type ◽  
Prediction Method ◽  
Analysis Data ◽  
Site Index ◽  
Douglas Fir ◽  
East Central ◽  
Engelmann Spruce ◽  
Dominant Height ◽  
Fort Apache Indian Reservation ◽  
Central Arizona

Abstract Dominant height and site index equations were constructed for Douglas-fir (Pseudotsuga menziesii var. glauca) and Engelmann spruce (Picea engelmannii) on the Fort Apache Indian Reservation, located in east-central Arizona. An indirect parameter prediction method was utilized to develop the equations from stem analysis data. The dominant height equation for Douglas-fir is a function of site index, age, habitat type groups, and soil texture groups. The Engelmann spruce dominant height equation is a function of only site index and age. Site index may be calculated directly by inverting the dominant height equations. West. J. Appl. For. 7(2):40-44.

Nitrogen fixation in woody residue of northern Rocky Mountain conifer forests

1987 ◽  
Vol 17 (10) ◽  
pp. 1283-1288 ◽  
Author(s):  
M. F. Jurgensen ◽  
M. J. Larsen ◽  
R. T. Graham ◽  
A. E. Harvey
Keyword(s):  
Wood Decay ◽  
Rocky Mountain ◽  
Brown Rot ◽  
Douglas Fir ◽  
Western Montana ◽  
N Fixation ◽  
Subalpine Fir ◽  
Brown Rot Fungi ◽  
Rocky Mountain Region ◽  
Northern Idaho

N fixation rates, as estimated by the acetylene reduction technique, were determined for large woody residues on four old growth conifer sites in western Montana and northern Idaho. Residue loadings ranged from <50 Mg ha−1 on a warm, dry Douglas-fir site in Montana to >150 Mg ha−1 on a highly productive, wet, cedar–hemlock site in northern Idaho. Lignin and carbohydrate analyses indicated that wood on these sites was being decayed primarily by brown rot fungi. Ethylene production rates increased on all sites as wood decay progressed. Assuming that N-fixing bacteria were active for 180 days year−1, N fixed in woody residues ranged from a high of nearly 1.5 kg ha−1 year−1 on a cedar–hemlock site to a low of 0.16 kg ha−1 year−1 on a Douglas-fir site. The application of the N fixation results from this study to the northern Rocky Mountain region indicated that the majority of stands in the Douglas-fir, subalpine fir, and cedar–hemlock cover types would have N gains <0.5 kg ha−1 year−1. However, in some areas where residue loadings are heavy, such as overmature stands on cool, moist sites, or following harvesting, N gains could be much greater.

Preliminary DRIS norms for coastal Douglas-fir soils in Washington and Oregon

1995 ◽  
Vol 25 (2) ◽  
pp. 208-214 ◽  
Author(s):  
J.S. Shumway ◽  
H.N. Chappell
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Integrated System ◽  
N Fertilizer ◽  
Soil Test ◽  
Fertilizer Response ◽  
Response Data ◽  
Limiting Nutrient ◽  
Diagnostic Work

The Diagnosis and Recommendation Integrated System (DRIS) has been used successfully in agricultural crops and holds promise for use in forest stands. This study used soil tests to develop DRIS norms and evaluate their effectiveness in coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forests. DRIS norms for nitrogen, phosphorus, potassium, and calcium were developed using soil test and site index data from 72 soil series that commonly support Douglas-fir in western Washington. The norms were tested using soil test and stand basal area growth response data from 20 thinned and 30 unthinned N fertilizer test sites in coastal Washington and Oregon. Response to urea fertilizer in thinned stands averaged 34% and 43% for 224 and 448 kg N•ha−1, respectively, when N was identified as the most limiting nutrient. When N was not the most limiting nutrient, N response averaged 8% and 10% for 224 and 448 kg N•ha−1, respectively. Results were similar in unthinned stands and thinned stands, although response to fertilizer appeared to be slightly less in unthinned stands when N was the most limiting nutrient. DRIS correctly classified 25 of the 33 sites (76%) where N fertilizer increased growth by more than 15%. More importantly, 13 of the 17 (76%) sites that responded by less than 15% were correctly identified by DRIS. The results clearly indicate that N fertilizer response is dependent on the interactions (balance) between soil nutrients at a given site. Future soil diagnostic work needs to focus on techniques, like DRIS, that provide an assessment of these interactions.

Partial cut harvesting and ectomycorrhizae: early effects in Douglas-fir-larch forests of western Montana

1980 ◽  
Vol 10 (3) ◽  
pp. 436-440 ◽  
Author(s):  
A. E. Harvey ◽  
M. J. Larsen ◽  
M. F. Jurgensen
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Douglas Fir ◽  
The Other ◽  
Western Montana ◽  
Root Tips ◽  
Residue Removal ◽  
Larch Forests ◽  
Early Effects

Numbers of ectomycorrhizae were assessed 3 years after harvesting approximately 50% of the overstory in two Douglas-fir-larch stands in western Montana, one was subjected to intensive residue removal, the other broadcast burned 1 year after harvest. Numbers of active ectomycorrhizal root tips were significantly reduced in the broadcast burned stand compared to either the intensively utilized stand or to an adjacent, undisturbed stand. This indicates that on difficult-to-regenerate sites, particularly where soil organic matter is low, it may be advantageous to dispose of slash created in partial cuts by means other than burning.

scholarly journals Relationship between environmental factors and site index in Douglas-fir plantations in central Italy

1998 ◽  
Vol 110 (1-3) ◽  
pp. 195-207 ◽  
Author(s):  
Piermaria Corona ◽  
Roberto Scotti ◽  
Neri Tarchiani
Keyword(s):  
Environmental Factors ◽  
Central Italy ◽  
Site Index ◽  
Douglas Fir

A Multipoint Felled-Tree Validation of Height–Age Modeled Growth Rates

2020 ◽  
Vol 66 (3) ◽  
pp. 275-283 ◽  
Author(s):  
Halli Hemingway ◽  
Mark Kimsey
Keyword(s):  
Growth Rates ◽  
Rocky Mountain ◽  
Site Index ◽  
Douglas Fir ◽  
Alternative Methods ◽  
Forest Site ◽  
Site Productivity ◽  
Site Factors ◽  
Forest Management Planning ◽  
Breast Height

Abstract Accurate measures of forest site productivity are essential for forest-management planning. The most common measure of site productivity is breast height–age site index (BHASI)—the expected height at a reference age. Error from including early growth in productivity estimates and limited applicability of any one BHASI model warrant development of alternative methods. Exploring alternatives may only be necessary if regional BHASI models are not accurately predicting growth rates. We compared modeled height growth rates for Rocky Mountain Douglas-fir (Pseudotsuga menziesii var. glauca) to felled-tree measurements to evaluate relative performance of a regional BHASI model. An orthogonal sampling design ensured samples were collected across a range of site factors known to influence Douglas-fir growth rates. Growth rates for each 10 m section were calculated and compared to BHASI modeled growth rates. The regional BHASI model underpredicted growth rates from breast height to 30 m. Observed growth rates from 10 to 30 m accounted for the majority of underprediction relative to BHASI modeled growth rates. An alternative multipoint method of defining site productivity is described. More research comparing BHASI and alternative methods is needed, given the growth rate error associated with one-point site productivity assessment.

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