Growth intercepts for estimating site quality of young white spruce plantations in north central Ontario

1987 ◽  
Vol 17 (11) ◽  
pp. 1385-1389 ◽  
Author(s):  
James S. Thrower
Keyword(s):  
Average Length ◽  
White Spruce ◽  
Site Index ◽  
Site Quality ◽  
North Central ◽  
Breast Height

Growth intercepts were used to estimate site index (defined as height of the trees 15 years after breast height (1.3 m) was attained) of dominant, planted white spruce (Piceaglauca (Moench) Voss) in north central Ontario. The growth intercepts were computed using four methods to select internode lengths from series of one through seven internodes, starting at each of eight heights from 0 to 3.0 m. Precision increased rapidly with more internodes and higher starting heights but quickly slowed to only marginal increases. Removing the smallest internode increased precision when growth intercepts started below 1.3 m. Removing the largest and both the smallest and largest internodes reduced precision from all starting heights. The most precise and practical growth intercepts used the average length of the first three, four, and five internodes above 2.0 m, explaining 83, 85, and 89% of the variation in site index, respectively.

scholarly journals Site-Index Curves and Growth Intercepts for Young White Spruce Plantations in North Central Ontario

2006 ◽  
Vol 23 (4) ◽  
pp. 257-263 ◽  
Author(s):  
Willard H. Carmean ◽  
Gerrit Hazenberg ◽  
James S. Thrower ◽  
Richard R. LaValley
Keyword(s):  
Regression Model ◽  
Nonlinear Regression ◽  
White Spruce ◽  
Analysis Data ◽  
Site Index ◽  
Nonlinear Regression Model ◽  
North Central ◽  
Breast Height ◽  
University Of Wisconsin ◽  
Dominant Height

Abstract Site-index (heightߝgrowth) curves, site-index prediction equations, and growth intercepts were developed from internode measurements and stem-analysis data using dominant trees in 69 plots located in white spruce plantations aged 19 to 32 years total age. Site-index curves were based on breast-height (1.3 m) age because our analyses show that height growth below breast height is slow and erratic and is poorly related to site index (dominant height at 15 years breast-height age). The most precise model for computing heightߝgrowth curves was a Newnham constrained polymorphic expression (Newnham, R.M. 1988. A modification of the Ek-Payandeh nonlinear regression model for site-index curves. Can. J. For. Res. 18:115ߝ120) of the Ek nonlinear regression model (Ek, A.R. 1971. A formula for white spruce site-index curves. University of Wisconsin For. Res. Note 161. 2 p). Comparisons showed that site-index curves in North Central Ontario were comparable to site-index curves for white spruce plantations in southeastern Ontario. The first three to five internodes above 2.0 m gave the most precise estimates of site index based on growth intercepts. North. J. Appl. For. 23(4):257–263.

Estimating Site Quality of Young Red Pine Plantations by Growth Intercept Methods

1988 ◽  
Vol 5 (2) ◽  
pp. 91-93 ◽  
Author(s):  
Timothy R. Bottenfield ◽  
David D. Reed
Keyword(s):  
Analysis Data ◽  
Site Index ◽  
Height Growth ◽  
Red Pine ◽  
Pine Plantations ◽  
Site Quality ◽  
Stem Analysis ◽  
Breast Height ◽  
Growth Intercept

Abstract Five growth intercept measurements were correlated with site index of red pine plantations in the northern Lakes States. The growth intercept variables were obtained by direct field measurement or indirectly through interpolation of stem analysis data. Growth intercepts represented both time (age in years) and distance (height in feet) measurements. Growth intercepts representing time and the age at breast height are not recommended for use in young red pine plantations. The amount of height growth in the first five annual whorls above 5 and 8 ft were good predictors of site index. North. J. Appl. For. 5:91-93, June 1988.

Growth Intercept Methods for Predicting Site Index in Red Pine Plantations in the Allegheny Plateau of Ohio

1990 ◽  
Vol 7 (1) ◽  
pp. 27-30 ◽  
Author(s):  
James H. Brown ◽  
Charles A. Duncan
Keyword(s):  
Site Index ◽  
Height Growth ◽  
Red Pine ◽  
Site Quality ◽  
Soil Horizon ◽  
Old Field ◽  
Annual Increment ◽  
Breast Height ◽  
Allegheny Plateau ◽  
Growth Intercept

Abstract Growth intercept (GI) techniques were evaluated for estimating site quality in red pine stands planted on old-field sites in the unglaciated Western and Central Allegheny Plateau regions of Ohio. Correlations between height growth of trees below breast height (BH) and height growth above BH were not statistically significant. Site index estimates were made using age at BH and height from BH to the growing tip. Three-year and 5-year growth beginning three internodes above the BH annual increment and 10-year growth beginning one internode above BH were more significantly correlated with height than were intercepts beginning at BH. In equations developed for predicting site index, 3-, 5-, and 10-year intercepts in combination with age accounted for 64 to 80% of the variation in tree heights. Combining thickness of the A soil horizon with GI and age statistically increased the variation accounted for in the 3- and 5-year GI equations; however, for field use, the improvement in accuracy was not sufficient to justify making the additional soil measurement. North. J. Appl. For. 7(1):27-30, March 1990.

Polymorphic site index curves for jack pine in Northern Ontario

2001 ◽  
Vol 77 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Willard H. Carmean ◽  
G. Hazenberg ◽  
G. P. Niznowski
Keyword(s):  
Analysis Data ◽  
Site Index ◽  
The United States ◽  
Jack Pine ◽  
Height Growth ◽  
Growth Patterns ◽  
Site Quality ◽  
Northern Ontario ◽  
Breast Height ◽  
The North

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.

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.

Site Quality Evaluation Models for Aspen (Populustremuloides Michx.) in Wisconsin

1975 ◽  
Vol 5 (4) ◽  
pp. 523-528 ◽  
Author(s):  
James S. Fralish ◽  
Orie L. Loucks
Keyword(s):  
Site Index ◽  
Water Holding Capacity ◽  
Site Quality ◽  
Quaking Aspen ◽  
North Central ◽  
Available Water ◽  
Soil Calcium ◽  
Calcium Magnesium ◽  
Regression Techniques ◽  
Water Holding

Soil and site relationships were studied in 32 mature quaking aspen (Populustremuloides Michx.) communities in north central Wisconsin. Multiple linear regression techniques indicated that soil texture, available water-holding capacity, water-table depth, and stand exposure were the most important factors controlling site index. Two models developed from combinations of these factors accounted for 62% of the variation in site index. Values for soil calcium, magnesium, potassium, and phosphorus were corrected for bulk density and summed to 12-, 24-, 36-, and 60-in. depths. When included in additional models, only magnesium to a 60-in. depth was found to have additional effect on aspen growth over and above that implicit in available water-holding capacity. The models were validated using 10 additional mature aspen stands and then applied to data from 10 stands in early stages of deterioration.

Confidence Interval for Site Index Using Curves Based on Stem Analyses

1971 ◽  
Vol 1 (4) ◽  
pp. 241-245 ◽  
Author(s):  
L. Heger
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
Confidence Intervals ◽  
White Spruce ◽  
Site Index ◽  
Stand Age ◽  
Average Quality ◽  
Breast Height ◽  
True Value ◽  
Index Level

A method was described for the derivation of confidence intervals for site index using site-index curves based on stem analyses. The method allows assessment of effects on index estimates due to stand age, index level, sample size of heights used in entering the curves, index age, and sample size underlying the curves. Of these effects, the first three were evaluated for a set of curves based on stem analyses of white spruce (Piceaglauca (Moench) Voss) and on index age of 50 years at breast height (BH). With sample averages of 20 heights, about 95% of index estimates were within ±5 ft (1.52 m) of the true value in spruce 25–100 years old at BH on both average quality and extreme quality sites. To ensure this precision in spruce younger than 15 years at BH, 50 heights were required on the average sites and more than 50 on extreme sites.

Early Height Growth and Site Index for Planted Red Pine in North Central Ontario

1995 ◽  
Vol 12 (1) ◽  
pp. 23-29
Author(s):  
William H. Carmean ◽  
James S. Thrower
Keyword(s):  
Growth Curves ◽  
Analysis Data ◽  
Site Index ◽  
Height Growth ◽  
Red Pine ◽  
North Central ◽  
Breast Height ◽  
Excellent Growth ◽  
Index Estimation ◽  
Best Estimates

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.

Forest understory plants as predictors of lodgepole pine and white spruce site quality in west-central Alberta

1991 ◽  
Vol 21 (11) ◽  
pp. 1675-1683 ◽  
Author(s):  
W. L Strong ◽  
D. J. Pluth ◽  
G. H. La Roi ◽  
I. G. W. Corns
Keyword(s):  
Lodgepole Pine ◽  
White Spruce ◽  
Site Index ◽  
Site Quality ◽  
Individual Species ◽  
Percent Cover ◽  
Regression Equations ◽  
Understory Species ◽  
Sources Of Error ◽  
Species Cover

The feasibility was explored of using cover estimates of a few understory species with high indicator value, rather than total species lists, to evaluate site quality for lodgepole pine (Pinuscontorta Loudon var. latifolia Engelm.) and white spruce (Piceaglauca (Moench) Voss). Analysis of 112 vascular and 7 nonvascular understory plant species from 211 lodgepole pine and white spruce dominated forests revealed that 39 and 30 of these species had significantly different percent cover among site-index classes for stem-analyzed pine and spruce, respectively. Individual species cover values were then used in simple and multiple linear regression equations to predict the site index (at 70 years) for pine and spruce in 60–90 year and 91–160 year stand age subsets. Equations for pine based on understory species cover explained 38% of the variance in site index in younger stands and 59% in older stands; comparable maxima for spruce were 42% in younger stands and 50% in older stands. These percentages may be too low for stand-alone predictions of site index. Several possible sources of error may cause the low explained variance, including crude field estimates and seasonal variations of cover. Many of these potential sources of error could be minimized, allowing better prediction of forest site quality.

scholarly journals A Height Growth Model and Associated Growth Intercept Models for Estimating Site Index in Black Spruce (Picea mariana Mill. B.S.P.) Plantations in Northern Ontario, Canada

2011 ◽  
Vol 28 (3) ◽  
pp. 129-137
Author(s):  
Martin M. Kwiaton ◽  
Jian R. Wang ◽  
Douglas E.B. Reid
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Site Index ◽  
Height Growth ◽  
Growth And Yield ◽  
Site Quality ◽  
Northern Ontario ◽  
Spruce Stands ◽  
Growth Intercept

Abstract Site quality is a key component of growth and yield models because height growth rates are known to be influenced by available site resources. Accurate prediction of future growth and yield requires site quality information for both plantations and natural stands. The forest industry in northern Ontario relies on high-quality wood and fiber from black spruce (Picea mariana Mill. B.S.P.); therefore, these tools are essential to ensure sustainable forest management. Although there are site index (SI) models for natural-origin black spruce stands in northern Ontario, models for estimating site quality of young black spruce plantations have not been developed. We used stem analysis data collected from 62 plantations (>40 years of age) of pure black spruce across northern Ontario to develop height growth, SI, and variable growth intercept models. The distinct height growth patterns we observed may be attributed to early silvicultural treatments (site preparation and herbicide) in plantations allowing black spruce trees to attain breast height (1.3 m) faster than in fire-origin stands in northern Ontario. Our models can be used to estimate site quality of black spruce plantations, a key consideration for silviculture and forest management planning. We also compare our managed stand SI model to one we developed from a comparable subset of data from black spruce growing in unmanaged stands and propose a method to assign an SI with a common base age to pure upland black spruce stands regardless of origin.

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