National site-index and height-growth curves for white spruce growing in natural stands in Canada

1991 ◽  
Vol 21 (10) ◽  
pp. 1466-1474 ◽  
Author(s):  
I. S. Alemdag

Based on stem analyses, national site-index equations and height-growth equations for white spruce (Piceaglauca (Moench) Voss) were developed covering an area from the Yukon to Newfoundland. The objective was to construct a single set of curves for each relationship by combining all regions, instead of separate curves for individual provinces or regions. The results of these tests indicated that the objective could be reached without any significant loss of accuracy. In developing the equations a modified form of the Chapman–Richards function was employed, and results are presented in tabular and graphical forms.

1984 ◽  
Vol 14 (6) ◽  
pp. 909-913 ◽  
Author(s):  
Y. S. Park ◽  
D. P. Fowler ◽  
J. F. Coles

Natural inbreeding and relatedness among neighboring trees were studied in several central New Brunswick populations of white spruce (Piceaglauca (Moench) Voss). Coefficients of relationship (r) were estimated by comparing the self-, neighbor-, open-, and unrelated-pollination effects on percent full seed. The estimates were 0.29 and 0.28 for neighbor and open pollinations, respectively. The effects of natural inbreeding on juvenile traits, e.g., germination and early growth, were slight while the effect on height growth increased with age at least to age 7 years. Neighboring white spruce trees growing in natural stands appear to be related at about the half-sib level (r = 0.25). Based on percent full seed, open-pollination approximates a level of inbreeding expected from trees related at a level well above that of half-sibs. Differential selection at the pre-embryo to early seedling stages results in progenies again related at the half-sib level. It is suggested that an inbreeding equilibrium exists in natural stands of white spruce and that this equilibrium approximates that expected from half-sib matings (F = 0.125). The inbreeding equilibrium is controlled, at least in part, by the frequency of lethal genes in the populations.


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


1999 ◽  
Vol 29 (12) ◽  
pp. 1989-1992 ◽  
Author(s):  
Gordon D Nigh ◽  
Bobby A Love

The best estimates of site index, an indicator of site productivity, are obtained from site trees. Undamaged site trees should be sampled to obtain unbiased estimates of site index. Two juvenile height growth modelling projects provided us with sufficient data to assess our ability to select undamaged lodgepole pine (Pinus contorta var. latifolia Dougl.) and white spruce (Picea glauca (Moench) Voss) site trees. The sample trees were split open to measure height growth from the terminal bud scars. Splitting the stems also revealed damage that was not visible from the outside of the tree. Over 50% of the lodgepole pine trees and 75% of the white spruce trees had damage, which was much higher than expected. Possible causes of damage are frost and insects. The damage does not significantly reduce the height of the spruce trees, but there is evidence that the heights of the lodgepole pine trees are reduced.


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.


2001 ◽  
Vol 31 (1) ◽  
pp. 165-173 ◽  
Author(s):  
C J Cieszewski

With two examples of five-parameter, fixed-base-age site index and height growth equations, I demonstrate three methods for deriving dynamic equations that are base-age invariant and use only three parameters. These are initial condition difference equations that compute appropriate heights at all base ages and provide compatible height and site index values from one common equation. Despite having fewer parameters, they can model a broader selection of curves than the original equations. The new equations are applicable for all situations in which the original equations could be applied. Methods demonstrated in this paper can enhance the development of all recursive and otherwise implicitly defined equations used for modeling of height, diameter, basal area, volume, number of trees per hectare, and investment yields.


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.


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