A Dynamic Stand Growth Model System for Loblolly Pine Responding to Mid-Rotation Treatments

Intensive loblolly pine (Pinus taeda L.) plantation management in the southeastern United States includes mid-rotation silvicultural practices (MRSP) like thinning, fertilization, competitive vegetation control, and their combinations. Consistent and well-designed long-term studies considering interactions of MRSP are required to produce accurate projections and evaluate management decisions. Here we use longitudinal data from the regional Mid-Rotation Treatment study established by the Plantation Management Research Cooperative (PMRC) at the University of Georgia across the southeast U.S. to fit and validate a new dynamic model system rooted in theoretical and biological principles. A Weibull pdf was used as a modifier function coupled with the basal area growth model. The growth model system and error projection functions were estimated simultaneously. The new formulation results in a compatible and consistent growth and yield system and provides temporal responses to treatment. The results indicated that the model projections reproduce the observed behavior of stand characteristics. The model has high predictive accuracy (the cross-validation variance explained was 96.2%, 99.7%, and 98.6%; and the prediction root mean square distance was 0.704 m, 19.1 trees ha−1, and 1.03 m2ha−1 for dominant height (DH), trees per hectare (N), and basal area (BA), respectively), and can be used to project the current stand attributes following combinations of MRSP and with different thinning intensities. Simulations across southern physiographic regions allow us to conclude that the most overall ranking of MRSP after thinning is fertilization + competitive vegetation control (Fert + CVC) > fertilization only (Fert) > competitive vegetation control only (CVC), and Fert + CVC show less than additive effect. Because of the model structure, the response to treatment changes with location, age of application, and dominant height growth as indicators of site quality. Therefore, the proposed model adequately represents regional growth conditions.

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Stand level pine response to occupancy of woody shrub and herbaceous vegetation

Canadian Journal of Forest Research ◽

10.1139/x99-068 ◽

1999 ◽

Vol 29 (7) ◽

pp. 979-984 ◽

Cited By ~ 8

Author(s):

Dwight K Lauer ◽

Glenn R Glover

Keyword(s):

Loblolly Pine ◽

Basal Area ◽

Pinus Elliottii ◽

First Year ◽

Shrub Cover ◽

Herbaceous Vegetation ◽

Vegetation Control ◽

Competing Vegetation ◽

Dominant Height ◽

Stand Basal Area

The relationship between age-5 pine height and vegetation cover was estimated for loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) stands using regression analysis. This paper utilizes results from four locations of a vegetation control study that included herbicide treatments to control woody shrub and herbaceous vegetation. Age-5 average dominant height was predicted from first-year herbaceous cover, untreated first-year shrub cover, and fifth-year shrub cover. Dominant height increased 0.5 m for each decrease of about 30% in either first year herbaceous cover, untreated first-year shrub cover, or year-5 shrub cover. Lack of vegetation control on beds where vegetation was allowed to recolonize before planting reduced dominant height an additional 0.5 m. A competition index was constructed that estimates the difference between "potential" and actual age-5 pine height. Stand-level models were developed to link age-5 pine height and occupancy of competing vegetation to quadratic mean DBH, specific DBH percentiles, and stand basal area. The effects of interspecific competition on stand basal area and diameter percentiles could be accounted for through the effects of competing vegetation on dominant height except for treatments that did not control woody shrubs.

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GROWTH AND YIELD OF EVEN-AGED Cupressus lusitanica PLANTATIONS IN SOUTHERN BRAZIL

FLORESTA ◽

10.5380/rf.v51i4.75135 ◽

2021 ◽

Vol 51 (4) ◽

pp. 980

Author(s):

Mário Dobner Jr.

Keyword(s):

Basal Area ◽

Site Index ◽

Growth And Yield ◽

Site Quality ◽

Timber Species ◽

Southern Brazil ◽

Cupressus Lusitanica ◽

Dominant Height ◽

Dominant Height Growth ◽

Quality Variation

Plantation forestry in southern Brazil demands additional timber species to a higher market differentiation by providing high quality timber and exploitation of market niches. Cupressus lusitanica has long been recognized for this purpose but, until now, it was not properly region-wide quantified in terms of growth and yield. The present study delivers the lacking quantitative approach, which may encourage the commercial use of the species. With this study it was aimed at collecting and processing quantitative data from all known C. lusitanica stands in southern Brazil. Inventories were carried out (60 ha, 6-39 years of age) in order to model the development of dominant height (h100), basal area, volume and dominant diameter (d100). Dominant height was the basis for site quality evaluation, delivering site index curves, which, together with the commercial volume of the stands, allowed yield modelling. A wide amplitude of dominant height growth was detected (10-30 m at 20 years), indicating a great site quality variation. At age of 20 years, commercial volumes of 110 and 620 m³ ha-1 were observed for site indexes of 14 and 26, respectively, equivalent to a maximum of 6-31 m³ ha-1 year-1 at ages between 16-18 years. Results demonstrated in a robust manner that C. lusitanica has a high potential for cultivation in southern Brazil. Thus, offering the opportunity of market differentiation by promoting market niches whose demands timber for special solid end-uses.

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Twelve-Year Results of a Loblolly Pine Site Preparation Study in the Piedmont and Upper Coastal Plain of South Carolina, Georgia, and Alabama

Southern Journal of Applied Forestry ◽

10.1093/sjaf/26.1.32 ◽

2002 ◽

Vol 26 (1) ◽

pp. 32-36 ◽

Cited By ~ 9

Author(s):

Stacey W. Martin ◽

Barry D. Shiver

Keyword(s):

South Carolina ◽

Loblolly Pine ◽

Coastal Plain ◽

Chemical Treatment ◽

Basal Area ◽

Site Preparation ◽

Growth And Yield ◽

Control Treatment ◽

Vegetation Control ◽

Stand Basal Area

Abstract A designed experimental study was installed at 25 separate locations in the Piedmont and Upper Coastal Plain regions of South Carolina, Georgia, and Alabama with the objective of evaluating the effects of different site preparation treatments, both chemical and mechanical, on growth and yield of cutover site-prepared loblolly pine (Pinus taeda L.) plantations. The following six site preparation treatments were included: (1) burn, (2) chop and burn, (3) shear, pile and disk, (4) chop, herbicide and burn, (5) herbicide and burn, and (6) herbicide, burn and complete vegetation control. The herbicide, burn and complete vegetation control treatment significantly increased mean dbh, mean height, stand basal area, and total and merchantable volume compared to all other treatments. The burn-only treatment consistently ranked worst compared to all other treatments. There were significant differences in mean dbh, mean height, stand basal area, and total and merchantable volume between: (1) the herbicide and burn, which is an operational chemical treatment, and (2) the average of the chop and burn treatment and the shear, pile and disk treatment, which are operational mechanical treatments. In all cases the operational chemical treatment performed significantly better than the average of the two operational mechanical treatments. Average 12-yr-old merchantable volumes (ft3/ac) across all locations by treatment were: burn (846), chop and burn (1,445), shear, pile and disk (1,740), chop, herbicide and burn (1,669), herbicide and burn (1,919), and herbicide, burn and complete vegetation control (2,546). There were no apparent trends in percent fusiform infection levels across site preparation treatment intensity levels. South. J. Appl. For. 26(1):32–36.

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A Novel Approach to Modelling Stand-Level Growth of an Even-Aged Forest Using a Volume Productivity Index with Application to New Zealand-Grown Coast Redwood

Forests ◽

10.3390/f12091155 ◽

2021 ◽

Vol 12 (9) ◽

pp. 1155 ◽

Cited By ~ 1

Author(s):

Mark O. Kimberley ◽

Michael S. Watt

Keyword(s):

New Zealand ◽

Growth Model ◽

Growth Models ◽

Stand Density ◽

Site Index ◽

Growth And Yield ◽

Productivity Index ◽

Site Quality ◽

Spatial And Temporal Variation ◽

Coast Redwood

Empirical growth models are widely used to predict the growth and yield of plantation tree species, and the precise estimation of site quality is an important component of these models. The most commonly used proxy for site quality in growth models is Site Index (SI), which describes the mean height of dominant trees at a specified base age. Although SI is widely used, considerable research shows significant site-dependent variation in height for a given volume, with this latter variable more closely reflecting actual site productivity. Using a national dataset, this study develops and describes a stand-level growth and yield model for even-aged New Zealand-grown coast redwood (Sequoia sempervirens). We used a novel modelling approach that quantifies site quality using SI and a volume-based index termed the 300 Index, defined as the volume mean annual increment at age 30 years for a reference regime of 300 stems ha−1. The growth model includes a number of interrelated components. Mean top height is modelled from age and SI using a polymorphic Korf function. A modified anamorphic Korf function is used to describe tree quadratic mean diameter (Dq) as a function of age, stand density, SI and a diameter site index. As the Dq model includes stand density in its formulation, it can predict tree growth for different stand densities and thinning regimes. The mortality model is based on a simple attritional equation improved through incorporation of the Reineke stand density index to account for competition-induced mortality. Using these components, the model precisely estimates stand-level volume. The developed model will be of considerable value to growers for yield projection and regime evaluation. By more robustly describing the site effect, the growth model provides researchers with an improved framework for quantifying and understanding the causes of spatial and temporal variation in plantation productivity.

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A Growth and Yield Model Incorporating Hardwood Competition for Natural Loblolly Pine Stands in the Georgia Piedmont

Southern Journal of Applied Forestry ◽

10.1093/sjaf/23.3.179 ◽

1999 ◽

Vol 23 (3) ◽

pp. 179-185 ◽

Cited By ~ 2

Author(s):

Stacey W. Martin ◽

Graham H. Brister

Keyword(s):

Loblolly Pine ◽

Basal Area ◽

Growth And Yield ◽

Parameter Estimates ◽

Yield Model ◽

Pinus Taeda L ◽

Projection Equations ◽

Georgia Piedmont ◽

The Impact ◽

Over Time

Abstract Using 5 yr remeasurement data from even-aged natural loblolly pine (Pinus taeda L.) stands in the Georgia Piedmont, a system of growth equations was developed to project pine yield over time that accounts for hardwood competition. In this system, the increase in the proportion of hardwood basal area over time is estimated, then the projected pine basal area and trees per acre are adjusted inversely to account for this increase. The parameter estimates for this system ensure compatibility between volume prediction and projection equations and the proportion of hardwood basal area, pine basal area, dominant height, and trees per acre projection equations. The whole-stand growth and yield system developed here coupled with published merchantable yield equations allow for the evaluation of the impact of hardwoods on future stand yield and product distributions. The results indicate that the impact of hardwood competition on pine yield is substantial and occurs mainly as a reduction in sawtimber volume. South. J. Appl. For. 16(3):179-185.

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Early Results from an Old-Field Loblolly Pine Spacing Study in the Georgia Piedmont with Competition Control

Southern Journal of Applied Forestry ◽

10.1093/sjaf/17.4.193 ◽

1993 ◽

Vol 17 (4) ◽

pp. 193-196 ◽

Cited By ~ 14

Author(s):

L. V. Pienaar ◽

B. D. Shiver

Keyword(s):

Loblolly Pine ◽

Basal Area ◽

Planting Density ◽

Yield Potential ◽

Stem Volume ◽

Annual Increment ◽

Average Growth ◽

Vegetation Control ◽

Early Results ◽

Georgia Piedmont

Abstract The study reported here provides information on the yield potential of improved loblolly pine seedlings planted on marginal agricultural cropland in the Georgia Piedmont with control of herbaceous competition. Early growth rates greatly exceed those in existing plantations established on cutover and mechanically site-prepared land in this region without additional control of competing vegetation. After 8 growing seasons, average tree height, average dbh, basal area per acre, and stem volume per acre were all influenced by planting density, but the mean annual increment of merchantable volume (trees 4.0 in. dbh and bigger to a 2.0 in. top diameter) at age 8 yr, for planting densities of 400 to 1000 trees/ac, was 230 ft³, or approximately 3 cords/ac/yr. This is more than twice the average growth rate in this region of cutover and mechanically site-prepared loblolly plantations without additional vegetation control. These results should be of particular interest to prospective participants in the Conservation Reserve Program (CRP). South. J. Appl. For. 17(4):193-196.

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The Effect of Physiographic Region and Geographic Locale on Predicting the Dominant Height and Basal Area of Loblolly Pine Plantations

Southern Journal of Applied Forestry ◽

10.1093/sjaf/30.3.147 ◽

2006 ◽

Vol 30 (3) ◽

pp. 147-153 ◽

Cited By ~ 8

Author(s):

Ralph L. Amateis ◽

Stephen P. Prisley ◽

Harold E. Burkhart ◽

Jiping Liu

Keyword(s):

Loblolly Pine ◽

Geographic Location ◽

Basal Area ◽

Atlantic Coastal Plain ◽

Regression Equations ◽

Dominant Height ◽

Northern Latitudes ◽

Intensively Managed ◽

Highly Correlated ◽

Atlantic Coastal

Abstract Analysis of loblolly pine plantation permanent plot data established across the southeastern United States indicates that differences in dominant height and stand basal area may be related to geographic locale as well as physiographic region. In general, holding other factors constant,plantations at southern latitudes and eastern longitudes have less basal area than plantations at northern latitudes and western longitudes. Plantations at southern latitudes and eastern longitudes in the Atlantic Coastal Plain are generally taller than elsewhere in the Atlantic Coastal Plain.These trends were consistent for a younger population of intensively managed plantations, as well as for an older population of nonintensively managed plantations. Regression equations were developed to test the significance of geographic location on the prediction of basal area and dominantheight. Even in the presence of stand variables that are highly correlated with basal area and dominant height, latitude and longitude were highly significant predictors. Including them as predictor variables increased considerably the precision of the regression equations. South. J. Appl.For. 30(3):142–146.

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A New Whole-Stand Model for Unmanaged Loblolly and Slash Pine Plantations in East Texas

Southern Journal of Applied Forestry ◽

10.1093/sjaf/33.2.69 ◽

2009 ◽

Vol 33 (2) ◽

pp. 69-76 ◽

Cited By ~ 5

Author(s):

Dean W. Coble

Keyword(s):

Loblolly Pine ◽

Basal Area ◽

Pinus Elliottii ◽

Current Data ◽

Slash Pine ◽

Pine Plantations ◽

Growth And Yield ◽

East Texas ◽

Age Classes ◽

Yield Model

Abstract A new compatible whole-stand growth-and-yield model to predict total tree cubic-foot volume per acre yield (outside and inside bark) was developed for unmanaged loblolly pine (Pinus taeda) and slash pine (Pinus elliottii) plantations in East Texas. This model was compared with the noncompatible whole-stand model of Lenhart (<xref ref-type="bibr" rid="B15-2127">Lenhart, 1996</xref>, Total and partial stand-level yield prediction for loblolly and slash pine plantations in east Texas, South. J. Appl. For. 20(1):36–41) and the <xref ref-type="bibr" rid="B15-2127">Lenhart (1996)</xref> model refit to current data. For the two species, all three models were evaluated with independent observed data. The model developed in this study outperformed both Lenhart models in prediction of future yield and basal area per acre for all age classes combined and by 5-year age classes. The Lenhart models consistently overestimated yield and basal area per acre. All three models predicted surviving trees per acre similarly. An example is also provided to show users how to use the new whole-stand model.

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Volume par unité de surface terrière, comme moyen d'évaluer la productivité de stations et la production des plantations d'épinette blanche au Québec

Canadian Journal of Forest Research ◽

10.1139/x74-018 ◽

1974 ◽

Vol 4 (1) ◽

pp. 127-137

Author(s):

S. Popovich

Keyword(s):

Basal Area ◽

White Spruce ◽

Growth And Yield ◽

Average Height ◽

Site Productivity ◽

Factors Influencing ◽

Dominant Height ◽

Average Form

This paper presents a method of evaluating site productivity by volume per square foot of basal area, comparing it with the method of dominant height. Based on this method, this study also offers tables for estimating the production of plantations in relation to the average height, the average form quotient, and to the average basal area of the stand. Moreover, this study gives practical instructions about several factors influencing growth and yield of white spruce (Piceaglauca, Moench.) plantations in the province of Quebec.

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Loblolly pine growth response to herbaceous vegetation control at different planting densities

Canadian Journal of Forest Research ◽

10.1139/x99-069 ◽

1999 ◽

Vol 29 (7) ◽

pp. 960-967 ◽

Cited By ~ 14

Author(s):

Harold Quicke ◽

Glenn Glover ◽

Ralph S Meldahl

Keyword(s):

Loblolly Pine ◽

Basal Area ◽

Planting Density ◽

Herbaceous Vegetation ◽

Vegetation Control ◽

Volume Yield ◽

Volume Response ◽

Adjustment Term ◽

Pinus Taeda L ◽

Positive Effect

Growth of Pinus taeda L., with and without control of competing herbaceous vegetation, was evaluated over 15 years at planting densities ranging from 747 to 2990 trees/ha. A height response to vegetation control of 0.9 m at age 5 decreased to 0.3 m at age 15. Convergence in the cumulative height between treated and untreated stands did not translate into converging basal area and volume yield. For 1500 and 2200 trees/ha, volume response to early vegetation control increased to age 15. For 800 trees/ha volume gains increased to age 12 and were stable between ages 12 and 15. Higher densities apparently captured more of the site resources made available through vegetation control. Age-15 volume gains for 2200, 1500, and 800 trees/ha were 71 (23%), 48 (17%), and 19 m3·ha-1 (8%), respectively. A separate adjustment term in height and basal-area models captured the short-term positive effect of vegetation control on height growth and longer term basal-area responses. Previously published height and basal-area models were modified to account for planting-density effects.

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