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

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.

1989 ◽  
Vol 4 (3) ◽  
pp. 85-88
Author(s):  
James L. Vander Ploeg ◽  
James A. Moore

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.


1985 ◽  
Vol 15 (4) ◽  
pp. 673-679 ◽  
Author(s):  
Robert A. Monserud

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.


1985 ◽  
Vol 9 (3) ◽  
pp. 166-169 ◽  
Author(s):  
Ralph L. Amateis ◽  
Harold E. Burkhart

Abstract Stem analysis data collected from dominant and codominant loblolly pine (Pinus taeda) trees in cutover, site-prepared plantations were used to develop site index curves. The data were collected over much of the natural range of loblolly pine. A separable differential equation which expresses height growth as a function of both height and age was used to develop the site index curves. These site index curves should be applicable to loblolly pine plantations on cutover, site-prepared lands through much of the South.1


1989 ◽  
Vol 4 (4) ◽  
pp. 136-142 ◽  
Author(s):  
Joseph E. Means ◽  
Thomas E. Sabin

Abstract On the Siuslaw National Forest in the central Oregon Coast Range we performed stem analysis of 55 trees selected with the criteria used by the forest. Height growth patterns of these trees were significantly different (α = 0.05) from commonly used regional height growth curves. Height growth patterns also differed significantly among groups of floristically similar plant associations in the Siuslaw National Forest. We constructed height growth and site index curves for two classes of plant associations having different height growth curve forms and for the combined data. Forest managers should consider building local height-growth and site-index curves if these are important in estimating stand yield or site productivity. West. J. Appl. For. 4(4):136-142, October 1989


2001 ◽  
Vol 77 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Willard H. Carmean ◽  
G. Hazenberg ◽  
G. P. Niznowski

Stem-analysis data from dominant and codominant trees were collected from 383 plots located in fully stocked, even-aged, undisturbed mature jack pine stands. Separate site index curves were independently formulated for four regions of northern Ontario using the Newnham constrained nonlinear regression model; these formulations were used for comparing regional site index curves at three levels of site index (10 m, 15 m and 20 m).Comparisons showed that no significant differences existed between the four regional curves as well as with previously published site index curves for the North Central Region. Each of the four regions had similar polymorphic height-growth patterns; therefore, data for the four regions were combined and a single formulation was used to develop a polymorphic set of site index curves for all of northern Ontario. We found that poor sites in each region had almost linear height growth up to 100 years breast-height age, but for each region height growth became more curvilinear with increasing site index. The recommended site index curves for northern Ontario are based on a formulation using only data from plots 100 years and less but this formulation was not significantly different from a formulation using only data from plots 80 years and less, or a formulation that included all data from plots older than 100 years breast-height age.Comparisons were made between our northern Ontario curves and other jack pine site index curves for Ontario as well as curves for other areas of Canada and the United States. These comparisons generally showed considerable older age differences. Reasons for these differences are uncertain but could be due to differences in the amount and kind of data used for these other curves, could be due to differences in analytical methods, or could be due to regional differences in climate, soil and topography. Key words: site quality evaluation, polymorphic height growth, regional site index curves, site index prediction equations, comparisons among site index curves.


2015 ◽  
Vol 45 (8) ◽  
pp. 1026-1033 ◽  
Author(s):  
Micky G. Allen ◽  
Harold E. Burkhart

Site index curves are generally developed from one of three data sources: (i) permanent sample plots, (ii) temporary sample plots, or (iii) stem analysis data. Permanent sample plots are considered to be the best data source for modeling height–age relationships; however, due to time and cost constraints, analysts may consider using temporary sample plots or stem analysis data for equation fitting. Temporary sample plot and stem analysis data, although more quickly obtained, require assumptions that are often not met when modeling site index. The question becomes how models developed from temporary sample plot or stem analysis data compare with models developed from permanent sample plot data. Data from a region-wide study in loblolly pine (Pinus taeda L.) plantations were used to develop site index curves from each of the three data sources. A form of the Chapman–Richards model was used for all three data sources to guard against confounding and to discern differences among the data sources when modeling height–age relationships. For the comparison and evaluation of behavior of different functions, the Schumacher model was also fitted to the three data sources. Curves developed from temporary sample plot and stem analysis data did not reproduce the height growth pattern exhibited in permanent sample plots, although curves derived from temporary plots were closer to the height growth pattern.


1996 ◽  
Vol 72 (2) ◽  
pp. 193-198 ◽  
Author(s):  
K. Klinka ◽  
H. Y. H. Chen ◽  
Q. Wang ◽  
R. E. Carter

Stem analysis data from even-aged Engelmann spruce (Picea engelmannii Parry ex Engelm.) and subalpine fir [Abies lasiocarpa (Hook.) Nutt.] stands on zonal sites in the Engelmann Spruce—Subalpine Fir biogeoclimatic zone of British Columbia were used to examine the relationships of site index and height growth and elevation, latitude, and longitude. Elevation and latitude were found to be strongly negatively correlated with site index of both study species. Spruce site index (bh age 50) was predicted to decrease 2.9 m and fir site index 2.5 m with every 100 m and 1° increase in elevation and latitude, respectively; however, (i) site index of both species appeared to decline faster with increasing latitude than elevation, and (ii) decrease appeared to be faster for spruce than for fir. Comparison of height growth curves for stands on zonal and azonal sites with similar site index from different elevations and latitudes suggested that there are probably inconsequential differences between the shape of curves for either species. These findings imply that (i) subalpine fir is better adapted to subalpine boreal climates than Engelmann spruce and (ii) development of polymorphic site index curves for estimating site index of both species may be appropriate. Key words: elevation, latitude, longitude, site index, height growth, Abies lasiocarpa, Picea engelmannii, Engelmann Spruce—Subalpine Fir zone


1995 ◽  
Vol 12 (1) ◽  
pp. 23-29
Author(s):  
William H. Carmean ◽  
James S. Thrower

Abstract Height-growth, site-index curves, and growth intercepts were developed from internode and stem-analysis data using dominant trees in 25 plots located in red pine plantations aged 26 to 37 yr. Height-growth curves were based on breast-height age because growth below breast height (1.3 m) was slow and erratic. Growth intercepts using the first three to five internodes above 1.5 m gave the best estimates of site index (dominant height at 20 yr breast-height age)for trees that were between 3 and 5 yr breast-height age; site-index estimation equations gave the best estimates for trees older than 10 yr breast-height age. These computed height-growth curves and growth intercepts and observed site index in north central Ontario were similar to other regions. The excellent growth observed in this study suggests that red pine should be given greater emphasis in future reforestation programs in north central Ontario. North. J. Appl. For. 12(1): 23-29.


2002 ◽  
Vol 17 (2) ◽  
pp. 66-74 ◽  
Author(s):  
David Brisco ◽  
Karel Klinka ◽  
Gordon Nigh

Abstract British Columbia's foresters currently use height growth curves developed with data from Montana to estimate the height and productivity of western larch (Larix occidentalis). The ability of the presently used curves to accurately predict the height growth of British Columbia's larch population is unknown. The production of new curves with local data could improve our ability to predict heights and allow increasingly precise yield projections in British Columbia. Data from 105 western larch stem analysis plots were collected from across the natural range of larch in British Columbia. The measured plots were naturally established, fire-origin, even-aged, and exhibited no indications of suppression or disease. A Richards function was fit to the data from each plot and used to generate height-age and site index information. Four models were fit to the plot data: conditioned logistic, Chapman Richards, conditioned Chapman Richards, and conditioned Weibull. The Chapman Richards model had the best fit to the data, although all four models had similar fit statistics. Overall, the Chapman Richards model is slightly more accurate at estimating heights than the currently used model. West.J. Appl. For. 17(2):66–74.


2002 ◽  
Vol 78 (2) ◽  
pp. 306-313 ◽  
Author(s):  
Gordon D Nigh ◽  
Pavel V Krestov ◽  
Karel Klinka

Black spruce (Picea mariana (Mill.) B.S.P.) is a boreal species that occurs extensively across the northern half of British Columbia. Forest managers require better growth and yield information for black spruce given the anticipated increase in demand for wood in the northern part of the province. The purpose of this study was to develop height-age models for black spruce. Ninety-one stem analysis plots were established in the BWBS and SBS biogeoclimatic zones. Three black spruce site trees from each plot were stem analyzed and the data were converted into height-age data. A conditioned log-logistic function was fit to the data. Indicator variables were used to test for differences in height growth between the sampled subzones. Although the warm subzones had different height growth patterns than the cool subzones, there was general agreement among the height-age models from British Columbia, Alberta, and New Brunswick up to about age 100. Key words: biogeoclimatic zones, height-age models, logistic function, site index, stem analysis


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