Assessing the effect of measurement error in age on dominant height and site index estimates

2011 ◽  
Vol 41 (8) ◽  
pp. 1698-1709 ◽  
Author(s):  
Chengcai Ni ◽  
Gordon Nigh
Keyword(s):  
Measurement Error ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Site Index ◽  
Stand Age ◽  
Initial Value ◽  
Dominant Height ◽  
Projection Length ◽  
Age Model ◽  
Projection Error

Stand age is often hard to measure accurately. Measurement error in age affects height estimates when height is projected from one age to another age. In this study, our objective was to derive an estimator for the variance of the component of projection error associated with the error in age. To evaluate the estimator, a simulation approach was employed and the results showed that the estimator worked well in most cases. When the variance of the error in age increases and the projection is forward, however, the estimator might not work as well as in other cases. Another objective was to examine how the error in age behaved under different height–age models and to what extent it affected height and site index estimates. The effect of the error in age depended on its magnitude, the height–age model, initial value of dominant height and age, and projection length. It was also shown that the effect was sometimes negligible, but it could be considerable in other cases. Data from 80 ponderosa pine ( Pinus ponderosa Dougl. ex Laws.) trees in British Columbia, Canada, were used in an illustrative example.

Ponderosa Pine Habitat Types as an Indicator of Site Quality in the Dixie National Forest, Utah

1989 ◽  
Vol 4 (2) ◽  
pp. 52-54 ◽  
Author(s):  
David L. Verbyla ◽  
Richard F. Fisher
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Species ◽  
Habitat Type ◽  
Site Index ◽  
Site Quality ◽  
National Forest ◽  
Habitat Types ◽  
Quercus Gambelii ◽  
Generally True

Abstract Forest habitat types have been purported to be useful indicators of site quality. This is generally true for habitat types with different dominant tree species. However, few have studied the site indicator value of habitat types with the same dominant tree species. We measured site index (base age 25) from 172 randomly selected plots within the ponderosa pine (Pinus ponderosa) zone of the Dixie National Forest, Utah. The range of site index within any one habitat type was broad. Poor sites occurred on all five habitat types. However, the best sites occurred only on the Pinus ponderosa/Symphoricarpos oreophilus and Pinus ponderosa/Quercus gambelii habitat types. Therefore, habitat type may be useful in predicting the best sites, but only if other site information is used in addition to habitat type. West. J. Appl. For. 4(2):52-54, April 1989.

A calibrateable site index model for Pinus kesiya plantations in southeastern Africa

2002 ◽  
Vol 32 (11) ◽  
pp. 1916-1928 ◽  
Author(s):  
Kalle Eerikäinen ◽  
Danaza Mabvurira ◽  
Ladislaus Nshubemuki ◽  
Jussi Saramäki
Keyword(s):  
Random Parameter ◽  
Site Index ◽  
Stand Age ◽  
Random Parameters ◽  
Index Model ◽  
Forest Inventories ◽  
Pinus Kesiya ◽  
Dominant Height ◽  
Random Parameter Model ◽  
Site Index Model

The aim of the study was to develop a site index model for Pinus kesiya Royle ex Gordon plantations in southeastern Africa based on the relationship between the dominant height and stand age. Conversely, analysis of dominant height and age data showed that the growth patterns of plantations were different. In addition, the asymptotes and forms of standwise dominant height curves varied within plantations. In developing a common site index model, instead of using the more common approach of estimating separate dominant height–age models for different plantations or sites, a mean curve approach based on a linear random parameter model with fixed and random parameters was applied. The random parameter model of this study was calibrated by predicting random parameters for the plantation and stand effects, in accordance with the standard linear prediction theory. The analyses showed that the calibration of the dominant height model was an efficient method to obtain reliable dominant height predictions of a stand, particularly when several dominant height–age observations from different stands of a plantation and at least one measured dominant height and stand age of a target stand are available. This is the case in many forest inventories based on temporary samples, i.e., cross-sectional data. The new site index model is a useful tool for use in different mensurational applications, and its properties can efficiently be utilized for example in forest inventories of P. kesiya plantations in southeastern Africa.

Dominant-height and site-index equations for ponderosa pine in east-central Arizona

1991 ◽  
Vol 21 (5) ◽  
pp. 606-611 ◽  
Author(s):  
W. F. Stansfield ◽  
J. P. McTague ◽  
R. Lacapa
Keyword(s):  
Ponderosa Pine ◽  
Habitat Type ◽  
Prediction Method ◽  
Site Index ◽  
Site Quality ◽  
Predictive Capability ◽  
East Central ◽  
Dominant Height ◽  
Central Arizona ◽  
Parameter Prediction

A dominant-height equation for ponderosa pine (Pinusponderosa Laws.) was constructed utilizing a parameter prediction method and a model by J.E. King. The site-index equation was obtained by inverting the dominant-height equation. A method was examined for indirectly obtaining parameter prediction equations. It proved superior to two direct parameter prediction approaches. Other site-quality variables, such as habitat type groups and elevation, were included in the dominant-height and site-index equations and were successful in refining predictive capability.

Thinning ponderosa pine (Pinus ponderosa) stands reduces mortality while maintaining stand productivity

2013 ◽  
Vol 43 (4) ◽  
pp. 311-320 ◽  
Author(s):  
Jianwei Zhang ◽  
Martin W. Ritchie ◽  
Douglas A. Maguire ◽  
William W. Oliver
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Bark Beetles ◽  
Basal Area ◽  
Stand Density ◽  
Growth Efficiency ◽  
Stand Age ◽  
Annual Increment ◽  
Stand Productivity ◽  
Residual Variation

We analyzed 45 years of data collected from three ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) levels-of-growing-stock installations in Oregon (OR) and northern California (CA), USA, to determine the effect of stand density regimes on stand productivity and mortality. We found that periodic annual increment (PAI) of diameter, basal area (BA), volume, and aboveground dry mass were significantly related to stand density index (SDI) and stand age at start of the period; the quadratic trends varied among sites. Precipitation departure from the normal for each period explained a significant amount of residual variation in all PAI variables except diameter. BA production did not change significantly as SDI exceeded 270 trees·ha−1 at the OR sites and 320 trees·ha−1 at the CA site. Stand productivity was the highest at Elliot Ranch (CA) and the least at Blue Mountains (OR). A similar trend held in growth efficiency under lower stand densities (SDI < 600). Most of the mortality was caused by Dendroctonus bark beetles in stands that exceeded SDI of 500 trees·ha−1. Limiting SDI was about 900 trees·ha−1, although plots at Elliot Ranch reached much higher than that. The results demonstrate that silvicultural control of stand density can be a powerful tool for reducing bark beetle caused mortality without sacrificing stand productivity.

scholarly journals Modeling dominant height growth using permanent plot data for Pinus brutia stands in the Eastern Mediterranean region

2021 ◽  
Vol 30 (1) ◽  
pp. eSC03
Author(s):  
Tammam Suliman ◽  
Uta Berger ◽  
Marieke Van der Maaten-Theunissen ◽  
Ernst Van der Maaten ◽  
Wael Ali
Keyword(s):  
Mediterranean Region ◽  
Eastern Mediterranean ◽  
Eastern Mediterranean Region ◽  
Site Index ◽  
Permanent Plots ◽  
Stand Age ◽  
Pinus Brutia ◽  
Dominant Height ◽  
Algebraic Difference ◽  
Generalized Algebraic Difference Approach

Aim of the study: At current, forest management in the Eastern Mediterranean region is largely based on experience rather than on management plans. To support the development of such plans, this study develops and compares site index equations for pure even-aged Pinus brutia stands in Syria using base-age invariant techniques that realistically describe dominant height growth.Materials and methods: Data on top height and stand age were obtained in 2008 and 2016 from 80 permanent plots capturing the whole range of variation in site conditions, stand age and stand density. Both the Algebraic Difference Approach (ADA) and the Generalized Algebraic Difference Approach (GADA) were used to fit eight generalized algebraic difference equations in order to identify the one which describes the data best. For this, 61 permanent plots were used for model calibration and 19 plots for validation.Main results: According to both biological plausibility and model accuracy, the so-called Sloboda equation based on the GADA approach showed the best performance.Research highlights: The study provides a solid classification and comparison of Pinus brutia stands growing in the Eastern Mediterranean region and can thus be used to support sustainable forest management planning.Keywords: site index; Generalized Algebraic Difference Approach (GADA); Sloboda equation.

Ten-year responses of ponderosa pine plantations to repeated vegetation and nutrient control along an environmental gradient

1999 ◽  
Vol 29 (7) ◽  
pp. 1027-1038 ◽  
Author(s):  
Robert F Powers ◽  
Phillip E Reynolds
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Plant Competition ◽  
Site Index ◽  
Stem Volume ◽  
Growth Responses ◽  
Xylem Water Potential ◽  
Potential Productivity ◽  
Vegetation Control ◽  
Moisture Availability

Factorial combinations of vegetation, nutrient, and insect control treatments were applied repeatedly to three contrasting California plantations of Pinus ponderosa var. ponderosa Dougl. ex Laws. Ten-year findings show that potential productivity is far greater than previously believed. Stem volume gains were linked directly with increases in crown volume. Insect problems were negligible. Vegetation control increased tree growth profoundly on xeric sites but less so on the most mesic. Where soil was both droughty and infertile, growth responses traced primarily to improved soil moisture availability and secondarily to better nutrition. The most fertile site also was droughty, and trees responded only to improved moisture availability. Water was less limiting on the most productive site. There, both fertilizers and herbicides triggered similar, substantive growth increases. Drought from both plant competition and climate reduced stomatal conductance, xylem water potential, and net assimilation rates. Assimilation rates increased linearly with site index, but treatment differences were not apparent once drought had peaked. Fertilization improved water-use efficiency where water stress was not extreme. Advantages in water availability to pines from vegetation control will dissipate as tree crowns close and transpiration rises.

Effects of Soil Compaction on Tree Volume in a California Ponderosa Pine Plantation

1986 ◽  
Vol 1 (4) ◽  
pp. 121-124 ◽  
Author(s):  
John A. Helms ◽  
C. Hipkin
Keyword(s):  
Bulk Density ◽  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Soil Compaction ◽  
Unit Area ◽  
Site Index ◽  
Soil Bulk Density ◽  
Pine Plantation ◽  
Alternative Approaches

Abstract Soil bulk density was measured around 423 trees (0.48 ha) in a 16-year-old ponderosa pine (Pinus ponderosa) plantation in the Sierra Nevada of California. A landing, skid trail, and areas adjacent to skid trails had soil bulk density increased by 43, 30, and 18% compared to areas with lowest bulk density. Due to differences in mean tree volume and initial survival, volume per unit area in these three locations was reduced by 69, 55, and 13%. Areas between skid trails were relatively unaffected. Assuming full stocking, reduction in productivity by age 40 yr in the most heavily compacted areas is equivalent to about one site index class. Further reduction in projected volume on highly compacted areas could occur due to lower initial survival. Alternative approaches to skid trail management are suggested. West. J. Appl. For. 1:121:124, Oct. 1986.

Reevaluating the self-thinning boundary line for ponderosa pine (Pinus ponderosa) forests

2013 ◽  
Vol 43 (10) ◽  
pp. 963-971 ◽  
Author(s):  
Jianwei Zhang ◽  
William W. Oliver ◽  
Robert F. Powers
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Stochastic Frontier ◽  
Site Occupancy ◽  
Stand Density ◽  
Site Index ◽  
The Self ◽  
Site Quality ◽  
Boundary Line ◽  
The Face

The self-thinning rule has been used extensively to predict population dynamics under intraspecific and interspecific competition. In forestry, it is an important silvicultural concept for maintaining stand health in the face of climate change and biotic stress, but uncertainty exists because traditional self-thinning limits were set subjectively without regard to site quality. We addressed this by analyzing ponderosa pine (Pinus ponderosa Lawson & C. Lawson) data from 109 research plots measured repeatedly and 59 inventory plots measured once across California. Self-thinning boundaries were fitted to the data with quantile regression and stochastic frontier function (SFF) techniques with and without site index (SI) as a covariate. The models from both methods fitted the data well with either research plots or all plots. Slopes for size-density trajectories were –0.45 with the 0.99 quantile and –0.47 for SFF. Maximum stand density indices (SDI) were 1250 trees per hectare (TPH) with the 0.99 quantile and 1050–1060 TPH with SFF. Mortality occurred when site occupancy from SFF reached 0.75, suggesting a zone of imminent mortality. Curvilinear trends in maximum SDI across SI for both methods indicate that self-thinning varies with site quality. Any management regimes that increase site quality and productivity will increase the self-thinning boundary.

scholarly journals Assessing site form as an indicator of site quality in even-aged Pinus radiata D. Don stands in north-western Spain

2019 ◽  
Vol 76 (4) ◽  
Author(s):  
Juan Alberto Molina-Valero ◽  
Ulises Diéguez-Aranda ◽  
Juan Gabriel Álvarez-González ◽  
Fernando Castedo-Dorado ◽  
César Pérez-Cruzado
Keyword(s):  
Pinus Radiata ◽  
Goodness Of Fit ◽  
Model Fitting ◽  
Site Index ◽  
Site Quality ◽  
Stand Age ◽  
Fit Statistics ◽  
Dominant Height ◽  
Western Spain ◽  
North Western

Abstract Key message Site form and site index have shown similar precision for estimating site quality in even-agedPinus radiataD. Don stands in north-western Spain. Additionally, SF presents the advantage that it does not require stand age information and can therefore be used in a wider set of situations in the forestry practice. Context Estimation of site quality is essential for characterizing, monitoring and predicting forest resources. Site index (i.e. the dominant height of the stand at a reference age) is ordinarily used to estimate site quality; however, this index is only useful for even-aged stands of known age. By contrast, SF is age-independent as it uses the dominant height of the stand at a reference dominant diameter. Aims The aim of this study was to compare the performance of SF and SI for site quality estimation in even-aged P. radiata stands. Methods Dynamic equations derived with the Generalized Algebraic Difference Approach (GADA) from the Hossfeld IV base model were fitted to predict site quality with both SI and SF. SF predictions were compared with SI regarding variability within the same plot and consistency in site quality predictions, using the observed maximum mean annual volume increment (MAI) as a direct measure of site quality. Results Both approaches showed good performance in model fitting and provided similar goodness-of-fit statistics and variability in the predictions. However, SI performed slightly stronger when related to MAI. Conclusion SF performed adequately in estimating site quality for even-aged P. radiata stands, with results comparable to those obtained using traditional SI.

scholarly journals Effects of Stand Density on Top Height Estimation for Ponderosa Pine

2012 ◽  
Vol 27 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Martin Ritchie ◽  
Jianwei Zhang ◽  
Todd Hamilton
Keyword(s):  
Ponderosa Pine ◽  
Stand Density ◽  
Tree Height ◽  
Site Index ◽  
Fixed Number ◽  
Site Quality ◽  
Height Estimation ◽  
Growing Stock ◽  
Dominant Height ◽  
Definition Of

Abstract Site index, estimated as a function of dominant-tree height and age, is often used as an expression of site quality. This expression is assumed to be effectively independent of stand density. Observation of dominant height at two different ponderosa pine levels-of-growing-stock studies revealed that top height stability with respect to stand density depends on the definition of the dominant height. Dominant height estimates calculated from a fixed number of trees per acre (ranging from 10 to 60 of the tallest trees per acre) were less affected by density than those calculated from a proportion (with the cutoff ranging from 95th to the 70th percentile) of the largest trees in the stand.

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