Estimation of Site Index Curve for 6 Oak Species in Korea

2020 ◽  
Vol 54 (3) ◽  
pp. 27-33
Author(s):  
Joon-Hyung Park ◽  
Sang-Hoon Chung ◽  
Sun-Hee Kim ◽  
Sang-Tae Lee
Keyword(s):  
Site Index ◽  
Site Index Curve ◽  
Index Curve

A Parsimonious Number of Growth Curves

1993 ◽  
Vol 10 (3) ◽  
pp. 132-136 ◽  
Author(s):  
Boris Zeide
Keyword(s):  
Growth Pattern ◽  
Ecological Factors ◽  
Growth Curves ◽  
Site Index ◽  
Growth Conditions ◽  
Growth Patterns ◽  
Construction Methods ◽  
Complex Interactions ◽  
Site Index Curve ◽  
Index Curve

Abstract Construction of new site index curves is often justified by a lack of growth information for a given species and site. This justification presumes that there is a one-to-one correspondence between growth pattern and stand conditions which are determined by numerous genetic and ecological factors together with their complex interactions. Because these factors are combined in an infinite number of ways, each stand is unique and needs its own site index curve. The effort required for collecting growth information would be prohibitive. This effort is also unnecessary because many existing curves coincide with each other and are, therefore, redundant. Differences in species, site, and construction methods do not prevent the appearance of the same growth patterns. These facts indicate that unique growth conditions do not mean that each stand has a unique growth pattern. Therefore, a more productive approach to growth modeling consists of distilling these patterns from existing curves and yield tables rather than piling up more new site index curves. Earlier investigations showed that the diversity in growth curves can be reduced to a small number (15-30) of growth types. The present study demonstrates that the number of types can be further reduced to 3-5 without sacrificing accuracy of growth predictions. North. J. Appl. For. 10(3):132-136.

scholarly journals Site-index Curve Shape in Spruce

1969 ◽  
Vol 45 (3) ◽  
pp. 184-186 ◽  
Author(s):  
L. Heger
Keyword(s):  
Picea Glauca ◽  
Black Spruce ◽  
White Spruce ◽  
Site Index ◽  
Absolute Difference ◽  
Curve Shape ◽  
Breast Height ◽  
Maximum Absolute Difference ◽  
Site Index Curve ◽  
Index Curve

Sets of site-index curves were prepared from stem analyses of white spruce (Picea glauca (Moench) Voss) and black spruce (P. mariana (Mill.) BSP.) from various regions in the boreal forest of Canada. Ordinates of the site-index curves, computed for 5-year breast-height age intervals up to 75 years, and for 10-foot site-index intervals up to 70 feet, were compared within the species for the same values of site index and age. For breast-height ages below 55 years and for site index below 70 feet, the maximum absolute difference among the ordinates did not exceed 2.0 feet in white spruce, and 1.6 feet in black spruce; the corresponding average deviations were 0.75 and 0.80 feet. For breast-height ages above 55 years, these differences increased with age and, at 75 years, reached 8.8 feet in white spruce, and 3.8 feet in black spruce; the corresponding average deviations were 4.40 and 1.53 feet.

Estimating variation in field crew estimates of site index

1996 ◽  
Vol 26 (4) ◽  
pp. 560-565 ◽  
Author(s):  
Ronald E. McRoberts
Keyword(s):  
Repeated Measures ◽  
Site Index ◽  
Mixed Effects ◽  
Nonlinear Mixed Effects ◽  
Red Maple ◽  
Height Measurement ◽  
Nonlinear Mixed Effects Modeling ◽  
Mixed Effects Modeling ◽  
Residual Variation ◽  
Index Curve

Variances of red maple (Acerrubrum L.) and yellow birch (Betulaalleghaniensis Britt.) site index estimates were determined using nonlinear mixed effects modeling procedures and simulations. Site index curves for each species were constructed using repeated height–age observations for individual trees and plot site index estimates. Plot site index was calculated by linearly interpolating between the height observations corresponding to age observations bracketing the index age for each tree and then averaging over trees. Nonlinear mixed effects modeling procedures were used to estimate the parameters of the site index curve model because of the longitudinal, repeated-measures nature of the height–age data. Plot site index variances were determined by simulating the procedure used by Forest Inventory and Analysis field crews of the USDA Forest Service North Central Forest Experiment Station. At least three site index trees per plot were necessary to consistently obtain 95% confidence intervals whose widths were within ±20% of means. Variation among site index trees, residual variation around estimated height–age curves, and errors in height measurement were the greatest contributors to variation in plot site index estimates. Because the effects of these sources of variation cannot be readily reduced, it is unlikely that the variances of site index estimates can be reduced.

Comparison of Douglas-fir site index and height growth curves in the Pacific Northwest

1985 ◽  
Vol 15 (4) ◽  
pp. 673-679 ◽  
Author(s):  
Robert A. Monserud
Keyword(s):  
Pacific Northwest ◽  
Growth Curves ◽  
Site Index ◽  
Height Growth ◽  
Douglas Fir ◽  
Stem Analysis ◽  
The Pacific ◽  
Northern Rockies ◽  
Growth Differences ◽  
Index Curve

Site index and height growth curves produced by the major Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) site index studies in the Pacific Northwest are graphically compared. Results indicate that differences in the height growth pattern of Douglas-fir increase with increasing distance between regions. Height growth differences were extremely small between the northern Rockies and the east side of the Cascades and were rather large between the Rockies and the west side of the Cascades. The relatively small differences between the northern Rockies and the Cascade crest fell between these two extremes. Very small differences were also found between Montana and northern Idaho. A second result of the comparisons is that the type of data and the resulting methodology used to develop the site index curve system are strongly related to the similarity of the resulting curves. Curves derived from felled-tree, stem-analysis studies were quite similar to each other, but differed substantially from curves derived by harmonized guide-curve methods. Furthermore, the guide-curve systems produced curves that were surprisingly similar to each other, even though different varieties of Douglas-fir from different regions were being compared. The magnitude of the differences that could be attributed solely to different methods of site curve construction (stem analysis vs. guide curve) was demonstrated to be quite large by applying both methods to the same data. The often untenable assumptions inherent in guide-curve systems appear to affect the shape of the curves more than real regional height growth differences.

Estimating Site Index in Even-Aged Northern Hardwood Stands

1982 ◽  
Author(s):  
Gayne G. Erdmann ◽  
Ralph M. Jr. Peterson
Keyword(s):  
Site Index ◽  
Northern Hardwood

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.

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