Session 6: II. Quantitative Silviculture and Growth & Yield
(R. Amateis)
Contents
CAPPS - A
New Effort to Study Intensively Managed Pine Plantations
Forest
Vegetation Simulator - Southern Variant
(Dennis M. Donnelly and Thomas Lloyd)
Testing
the Accuracy of Growth and Yield Models for Southern Hardwood Forests
Quantifying
Effects of Intensive Management on Wood Properties of Loblolly Pine
(Dick Daniels
and Alexander Clark III)
Age
12 Results of a Loblolly Pine Improved Planting Stock-Vegetation Control Study
(Stacey W. Martin and Barry D. Shiver)
A New Effort to Study Intensively Managed Pine Plantations:
CAPPS Consortium for Accelerated Pine Production Studies
Bruce E. Borders
School of Forest Resources
University of Georgia
Athens 30602 USA
Abstract
Today, the forest products industry is facing increasing demand for wood and wood products from an ever-decreasing land base. To help meet this demand for wood fiber, forest plantation management is necessarily becoming very intensive. Intensive management of pine plantations includes vegetation control, fertilization, use of genetically improved planting stock, subsoiling, insect control, irrigation and possibly other cultural treatments. Clearly, such cultural treatments are very capital intensive.
We currently know that production rates can be increased dramatically using combinations of vegetation control and fertilization. However, optimal (economic and biological considerations) timing and intensity of such treatments have not been defined. It is necessary to understand how plantations and individual trees within plantations respond to various cultural treatments to make efficient use of capital for application of these cultural treatments. CAPPS is envisioned as an effort to improve our understanding of tree responses to intensive cultural treatments. With this improved understanding we anticipate defining silvicultural prescriptions to produce various end products in the most efficient way possible. Additionally, we propose to develop both process models and management growth and yield models for intensively managed loblolly pine plantations. Finally, wood quality of intensively managed trees will be evaluated.
All studies described below will make use of existing field sites that are part of the study known as the “Acid Rain Study” at the School of Forest Resources of the University of Georgia. The oldest plots in this study are currently 13years old and are among the fastest growing loblolly pine plantations in the Southeast (average annual production on certain sites exceeds 450 cubic feet of volume). Thus, we have a unique opportunity to make use of this living laboratory to increase our understanding and knowledge of intensively managed loblolly pine plantations.
*Presented by Bruce E. Borders.
Overview of Forest Vegetation Simulator in the South
Dennis M. Donnelly
Forest Growth Modeling Group
USDA Forest Service
3825 East Mulberry Street Fort Collins 80524
USA
F. Thomas Lloyd
USDA Forest Service
Southern Research Station, Asheville, NC
Abstract
During the last five years, the Forest Vegetation Simulator (FVS -- formerly known as Prognosis) has had several noteworthy additions to its processing capability and to the suite of regional variants now or soon to be available. This presentation summarizes enhancements such as computing platform changes, availability of the Suppose "front end", the Stand Visualization System, and several other "post-processors". Also presented is information about the status of four southern variants -- the Southeast Twigs variant, the "southern variant", the Southern Appalachian variant, and the Ozark variant.
*Presented
by Dennis Donnelly.
Testing the Accuracy of Growth and Yield Models for Southern
Hardwood Forests
Michael H. Rauscher
Southern Research Station
USDA Forest Service
1577 Brevard Rd. Asheville, NC 28806 USA
Michael J. Young
Champion International Corporation, Lake States Region
Forest Resources
W6582 U. S. Highway 2, Norway, MI 49870
Charles D. Webb
Webb Forest Decisions
107 Spring Hollow Lane, Cary, NC 27511
Daniel J. Robison
Hardwood Research Cooperative, North Carolina State
University
Box 8008, Raleigh, NC
27695-8008
Abstract
The accuracy of 10 growth and yield models for Southern Appalachian upland hardwood forests and Southern bottomland forests was evaluated. Results indicate that GHAT, NATPIS, and a locally calibrated version of NETWIGS may be regarded as being operationally valid models for growth and yield predictions for Southern Appalachian yellow-poplar and mixed oak forests that fall within the range of characteristics of the test data set. In brief, these characteristics are: even-aged, yellow-poplar or mixed oak dominated overstory, dry-mesic to wet-mesic moisture regimes, 20 to 100 years in age, and 25 to 230 sq. ft. of basal area. For yellow-poplar dominated stands the appropriate site index range is 74 to 138 ft. (base age 50) and for mixed oak the appropriate site index range is 60 to 110 ft (base age 50 for northern red oak). No publicly available growth and yield models specifically developed for Southern bottomland hardwood forests exist. Four general models that contain most of the applicable species to predict growth of these forests were evaluated. SETWIGS was found to be the most accurate of the four models tested and is recommended for use if the reported level of accuracy is acceptable and the target stand characteristics fall within the range of our test data set. In brief, these characteristics are: even-aged, swamp or non-swamp sites, 10 to 60 years in age, and 30 to 370 sq. ft. of basal area. The appropriate site index range is 66 to 125 feet (base age 25 years).
*Presented by Michael H. Rauscher.
Quantifying effects of intensive management on wood
properties of loblolly pine
Richard F. Daniels
School of Forest Resources
University of Georgia
Athens 30602 USA
Alexander Clark III
USDA Forest Service
Southern Research Station
Athens, GA 30602
Abstract
The forest products industry will increasingly rely upon fast-growing plantations to furnish the raw material for solid wood and fiber processing facilities. How will the changes in intensive silviculture and forest genetic improvement affect the quality, product mix, and profitability of wood and fiber products? The Wood Quality Consortium at the University of Georgia in Athens is enabling research toward a thorough understanding of wood properties from fast-growing plantations in southern United States, with initial emphasis on loblolly pine. Three phases of research have been identified: 1) Characterize wood variation of current plantations and establish a wood properties baseline; 2) Quantify of the effects of new intensive silviculture and forest genetics on wood properties; and 3) Model strength and yield properties in terms of basic wood properties. The objective is to be able to predict, from stump to tip and pith to bark, the changes due to intensive management that occur to wood properties such as specific gravity, cell wall thickness, tracheid length, and microfibril angle. These properties are highly correlated with strength and yield properties of fiber products and solid wood. Additional wood properties may also be identified as important, including chemical analysis (e.g. lignin, cellulose), moisture content, compression wood, and pathogen effects. Branch dynamics and distributions will also be used to predicting recovery and value of solid products.
Many factors are thought to affect basic wood properties, including tree age, stand density, geography, site quality, growth rate, and silvicultural treatments. Knowledge of the effect of environmental variables, such as soils, climate and site quality on wood properties is incomplete and unsystematic. A systematic baseline of data is being developed in which variability in basic wood properties and branch distributions are characterized within and among trees, by size, age, site quality, and geographic location. Data are needed from well-designed studies to address the relationships between growth rate and wood quality. Excellent long-term field studies exist currently, through several research cooperatives across the South. Through partnerships with these cooperatives and industrial membership support, the Consortium will collect new wood and fiber data relating growth rates and treatments to the basic wood. Understanding the three dimensional variation of basic wood properties and how they are affected by intensive management will lead to construction of stump to tip and pith to bark prediction equations for wood and fiber product properties such as strength, stiffness, dimensional stability, visual appearance and coarseness. These models will then allow wood quality and value considerations to be included in forest management and mill supply decisions.
*Presented
by Dick Daniels.
Age 12 Results of A Loblolly Pineimproved Planting
Stock-Vegetation Control Study
Stacey W. Martin and Barry D. Shiver
School of Forest Resources
University of Georgia
Athens 30602 USA
Abstract
The Plantation Management Research Cooperative at the University of Georgia designed and installed a study in 1986-87 with the following objectives:
(1) to evaluate the impact of first generation genetic improvement on yields for planning purposes,
(2) to evaluate the impact on yields of combining genetic improvement and vegetation control, and
(3) to evaluate single family genetically improved plantations versus bulk lot genetically improved plantations.
A designed experimental study was established at 16 locations in the Coastal Plain region of Georgia and northern Florida, and at 15 locations in the Piedmont region of South Carolina, Georgia and Alabama. Eight 0.4 ac treatment plots were included at each study installation:
Unimproved stock, no vegetation control (UNC),
Unimproved stock, complete vegetation control (UCC),
Bulk lot improved stock, no vegetation control (BNC),
Bulk lot improved stock, complete vegetation control (BCC),
Replicate plot of one of the first four treatments,
Single family improved stock, no vegetation control (SNC),
Single family improved stock, complete control (SCC), and
Replicate plot of one of the single family treatments.
A mixed model approach was used to analyze the age 12 measurements and the 3-yr periodic growth from ages 6 to 9, and 9 to 12 yr. Installation and all installation interactions were treated as random factors and competition control and genetics were treated as fixed factors. The two levels of competition control were either none other than that provided by the operational site preparation or complete control. Genetic improvement was either unimproved, bulk lot or single family. The analyses for the Costal Plain and Piedmont regions were completed separately on the following dependent variables: average dbh, range in dbh, skewness statistic of the dbh distribution, average dominant height, surviving trees per acre, basal area per acre, total and merchantable stem volume and percent fusiform rust infection.
Competition control significantly increased average tree characteristics and basal area per acre in both the Piedmont and Coastal Plain regions. In the Piedmont region, improved genetics significantly increased average dbh. Average dominant height was significantly increased in both physiographic regions by improved genetics. For Coastal Plain loblolly pine, improved genetics significantly increased basal area per acre while, in the Piedmont region, there was a significant interaction between competition control and genetics with respect to basal area per acre and trees per acre. Total volume was significantly increased by both improved genetics and competition control. In terms of total volume, increases up to 45% and 39% can be obtained from using complete vegetation control in the Coastal Plain and Piedmont regions, respectively. Improved genetic stock can increase total volume an average of 11% to 16% in the Coastal Plain and 10% to 19% in the Piedmont. For both total and merchantable volume the effects of competition control and improved genetics were additive. This additive nature of the effects indicates that managers should obtain the full benefit of these treatments. In the Coastal Plain region, neither competition control nor genetics significantly affected surviving trees per acre. In both regions, improved genetics significantly reduced the percent fusiform infection. Additionally, no significant differences were detected between bulk lot and single family plantings across all dependent variables.
The results of the 3-yr periodic growth analysis indicated that the no competition control plots had significantly larger 3-yr growth in mean dbh in both the Piedmont and Coastal Plain regions than complete vegetation control plots. In terms of mean dominant height, improved genetic stock continued to outgrow the unimproved stock in both physiographic regions. During the 3-yr period between 9 and 12 yrs there were no significant differences in dominant height growth between the two levels of competition control in the Coastal Plain, while in the Piedmont region no control had significantly greater 3-yr growth than the complete control. In the Coastal Plain region, improved genetics and complete competition control continued to significantly increase volume growth during both periods. During the period from 6 to 9 yrs, both competition control and genetics additively increased volume growth in the Piedmont region, while during the period from 9 to 12, the interaction between genetics and competition control was significant.
*Presented by Stacey Martin.
Last revised: April 6, 2000