A Generalized Height-Diameter Equation for Coastal California Species

1988 ◽  
Vol 3 (4) ◽  
pp. 113-115 ◽  
Author(s):  
Bruce E. Krumland ◽  
Lee C. Wensel
Keyword(s):  
Pseudotsuga Menziesii ◽  
Site Index ◽  
Douglas Fir ◽  
Sequoia Sempervirens ◽  
Small Samples ◽  
Diameter Distribution ◽  
Northern California ◽  
Local Volume ◽  
Total Height ◽  
Volume Table

Abstract The equation H = Hm exp [-b(D-c - Dm-c)] is proposed for estimating the total height of trees on growth and inventory plots. This estimator requires only the computation of average dbh (Dm) and average total height (Hm) of a sample of trees selected from the upper one-fifth of the stand diameter distribution. The procedure is also efficient because this stand component is also used to estimate site index. With small samples, these equations were found to be accurate in local volume table construction. Results are illustrated using redwood (Sequoia sempervirens) and Douglas-fir (Pseudotsuga menziesii) data from northern California. West. J. Appl. For. 3(4):113-115, October 1988.

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.

A New Look at Pruning Coast Douglas-Fir

1988 ◽  
Vol 3 (2) ◽  
pp. 46-48
Author(s):  
Roger D. Fight ◽  
James M. Cahill ◽  
Thomas D. Fahey ◽  
Thomas A. Snellgrove
Keyword(s):  
Interest Rates ◽  
Pseudotsuga Menziesii ◽  
Computer Software ◽  
New Product ◽  
Site Index ◽  
Douglas Fir ◽  
Product Recovery ◽  
Financial Returns ◽  
New Look

Abstract Pruning of coast Douglas-fir for (Pseudotsuga menziesii var. menziesii) lumber was evaluated by using new product-recovery information and new computer software. The results showed that higher financial returns from pruning are achieved by pruning early in stands that have a higher site index and that will be fertilized. Interest rates and the premium for clear lumber will have major impacts on the dollar return from pruning. West. J. Appl. For. 3(2):46-48, April 1988.

Growth Response to Fertilization in Young Douglas-Fir Stands

1989 ◽  
Vol 4 (4) ◽  
pp. 116-119 ◽  
Author(s):  
Linda S. Heath ◽  
H. N. Chappell
Keyword(s):  
Pseudotsuga Menziesii ◽  
Growth Response ◽  
Volume Growth ◽  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Intermediate Region ◽  
Fertilizer Response ◽  
Breast Height ◽  
Inverse Effect

Abstract Response surface methodology was used to estimate six-year volume growth response to 1 application of 200 lb nitrogen per acre in unthinned and thinned Douglas-fir (Pseudotsuga menziesii) stands of breast height age (bha) 25 years or less. Regional mean fertilizer response was 16% in unthinned stands and 20% in thinned stands. Site index had an increasingly inverse effect on response as basal area increased in both unthinned and thinned stands. Response varied little over site index in regions of low basal area, decreased moderately as site index increased in the intermediate region, and decreased rapidly in the high basal area region. West. J. Appl. For. 4(4):116-119, October 1989.

Yield Comparison of Three Douglas-Fir Plantations on Former Farmland in Western Washington

1990 ◽  
Vol 5 (4) ◽  
pp. 123-126
Author(s):  
Marshall D. Murray ◽  
Constance A. Harrington
Keyword(s):  
Pseudotsuga Menziesii ◽  
Nutrient Availability ◽  
Site Index ◽  
Douglas Fir ◽  
Annual Increment ◽  
Volume Yield ◽  
Western Washington ◽  
Natural Stands ◽  
Mean Annual Increment ◽  
Enhanced Yield

Abstract Yields of three Douglas-fir (Pseudotsuga menziesii) plantations on former farmland were substantially greater than DFSIM yields for the plantations based on site index estimates from adjacent natural stands. Volume yield per acre of trees 1.6 in. dbh and larger was 40 to 57% greater in the actual plantations than in the simulations. For trees 7.6 in. dbh and larger, volume yield of the actual plantations was 85 to 151% greater than the simulated yields. Mean annual increment of the actual plantations was 56 to 69% greater than the simulated values. In addition, top height was greater in two of the plantations than predicted. Running a second set of simulations with site index estimates based on plantation trees reduced the discrepancy in yields but still resulted in substantial underpredictions. Some possible reasons for enhanced yield of the plantations on former farmland are greater site uniformity, reduced vegetative competition, and increased nutrient availability. West. J. Appl. For. 5(4):00-00, October 1990.

Assessing the impact of current and projected climates on Douglas-Fir productivity in British Columbia, Canada, using a process-based model (3-PG)

2010 ◽  
Vol 40 (3) ◽  
pp. 511-524 ◽  
Author(s):  
Nicholas C. Coops ◽  
Robbie A. Hember ◽  
Richard H. Waring
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Site Index ◽  
Douglas Fir ◽  
Climatic Variation ◽  
Climate Forecasts ◽  
Fine Spatial Resolution ◽  
Viable Approach ◽  
The Impact ◽  
Process Based Models

Predicted climate change is expected to significantly affect tree growth in many areas. We used a process-based model (Physiological Principles for Predicting Growth, 3-PG) to evaluate how climatic variation might alter growth of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco and Pseudotsuga menziesii (Mirb.) Franco var. menziesii ) across biogeoclimatic zones in British Columbia. The results indicate that there will be significant changes in site index (defined as the height (in metres) of dominant trees at 50 years) over this century. In the interior, a reduction in site index is likely, particularly in stands with mid-range values of site index (25–30 m), with many of the interior bioecoclimatic zones predicted to experience a gradual mean decrease in site index by up to 10%. Individual sites may decrease by as much as 40% from current values. In contrast, site index along the coast overall is predicted to increase to a maximum of 43 m by 2080. In the Coastal Western Hemlock zone, however, mean site index is likely to increase from 26 m to only 34 m. We believe that combining process-based models with fine-spatial resolution climate forecasts offers a viable approach to assess future changes in forest productivity.

Douglas-fir height growth affected by western spruce budworm

1983 ◽  
Vol 13 (3) ◽  
pp. 445-450 ◽  
Author(s):  
G. A. Van Sickle ◽  
R.I. Alfaro ◽  
A.J. Thomson
Keyword(s):  
British Columbia ◽  
Recovery Period ◽  
Spruce Budworm ◽  
Site Index ◽  
Height Growth ◽  
Douglas Fir ◽  
Western Spruce Budworm ◽  
Total Height

Detailed dissections of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees repeatedly defoliated by the western spruce budworm (Choristoneuraoccidentalis (Freeman)) in two areas of British Columbia indicated that budworm severely affected height growth. Dissected trees lost an average 7.3 internodes in each infestation, of which 4.2 were destroyed or failed to grow during the budworm feeding and recovery periods, and 3.1 were existing internodes lost to dieback. An average of one internode of subnormal size, produced during the recovery period, was also present. Total height was reduced by 32% (11.4 m) and 19% (5.9 m) in areas that sustained four and two infestations respectively. Budworm infestations lead to an underestimation of the site index for Douglas-fir in the affected areas.

Estimating Dominant Height and Site Index of Even-Aged Interior Douglas-Fir in British Columbia

1992 ◽  
Vol 7 (1) ◽  
pp. 20-25 ◽  
Author(s):  
James S. Thrower ◽  
James W. Goudie
Keyword(s):  
British Columbia ◽  
Linear Model ◽  
Pseudotsuga Menziesii ◽  
Site Index ◽  
Logistic Function ◽  
Height Growth ◽  
Douglas Fir ◽  
Stem Analysis ◽  
Inland Empire ◽  
Dominant Height

Abstract Height-age and site-index curves were developed from stem analysis of 262 Douglas-fir trees (Pseudotsuga menziesii var. glauca) from 68 plots in the Interior Douglas-fir, Interior Cedar-Hemlock, and Sub-boreal Spruce Biogeoclimatic zones in the interior of British Columbia. Plots ranged in site index from about 8 to 30 m and in age from about 60 to 350 years; however, the analyses were limited to data up to 100 years of age. A conditioned logistic function was selected for predicting height, and a linear model was selected for predicting site index. The curves are similar to those developed in comparable studies in the Inland Empire, but differ substantially from curves developed in British Columbia from temporary sample plots. This study supports previous observations that the pattern of height growth for a given site index varies among ecologically different areas. West. J. Appl. For. 7(1):20-25.

Physiologically derived predictions of Douglas-fir site index in British Columbia

2009 ◽  
Vol 85 (5) ◽  
pp. 733-744 ◽  
Author(s):  
Nicholas C Coops ◽  
Robbie A Hember
Keyword(s):  
British Columbia ◽  
Soil Water ◽  
Pseudotsuga Menziesii ◽  
Tree Height ◽  
Site Index ◽  
Douglas Fir ◽  
Forest Growth ◽  
Individual Tree ◽  
Forest Growth Model ◽  
Wide Range

Both the coastal and interior varieties of Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco; Pseudotsuga menziesii var. glauca) are found throughout a wide range of environmental conditions across British Columbia. The species is long-lived and can grow rapidly to standing volumes that approach the highest recorded among temperate conifers. Understanding the growth of the species across British Columbia, and its site index (defined as individual tree height at 50 m) is important for forest managers for both production and conservation objectives. To date, predictions of site index have traditionally been derived from forest inventory using estimates of species, height and age combined with the appropriate height–age model. More recently, process-based modelling has offered a viable alternative approach due to increased computing power, model simplifications and availability of input data. In this paper we applied a physiological forest growth model, 3-PG (Physiological Principles Predicting Growth) to predict and map site index of Douglas-fir across British Columbia at 1-km cell resolution. Our model predictions were scaled-up and compared to independent estimates of average site index for subzones from the British Columbia Biogeoclimatic Ecosystem Classification (BEC) system. Results indicated the 3-PG predictions closely matched those summarized by the BEC sub-zones (r = 0.86, p<0.001, SE = 3.0m). Predicted environmental limitations of growth suggest that the coastal variety of the species is most severely affected by temperature and frost constraints, and in some locations, soil water stress, whereas the interior variety is principally restricted by soil water availability. The proposed modelling approach complements ecological classifications and offers the potential to identify the most favourable sites for management of other native tree species under current and projected climates. Key words: Douglas-fir, site index, physiological modelling, 3-PG model, forest productivity, British Columbia, Canada

PITYOPHTHORUS ORARIUS BRIGHT (COLEOPTERA: SCOLYTIDAE) IN A NORTHERN CALIFORNIA DOUGLAS-FIR SEED ORCHARD: EFFECT OF CLONE, TREE VIGOR, AND CONE CROP ON RATE OF ATTACK

1994 ◽  
Vol 126 (5) ◽  
pp. 1111-1118 ◽  
Author(s):  
Nancy G. Rappaport ◽  
David L. Wood
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Attack Rate ◽  
Oviposition Behavior ◽  
Seed Orchard ◽  
Geographic Range ◽  
Douglas Fir ◽  
Northern California

AbstractThe geographic range of the Douglas-fir twig beetle, Pityophthorus orarius Bright, was extended beyond the original provenance of southern British Columbia to northern California. A survey of 457 Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees in 1985 revealed that those with heavy cone crops were more likely to be infested by twig beetles than were those with a light crop. Furthermore, attack rates differed among clones. A second survey done in 1987 confirmed the importance of clone and cone crop in attack rate. In this survey, stressed trees were attacked at a higher rate than unstressed trees. Beetle distributions appeared clumped in both surveys, possibly because of semio-chemicals or oviposition behavior.

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