MODELING COMPETITION EFFECTS ON TREE GROWTH AND FOREST STAND DEVELOPMENT

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: MCINTIRE-STENNIS
• Reporting Frequency: Annual
• Accession No.: 1003357
• Project Start Date: Sep 1, 2014
• Project End Date: Aug 31, 2019
• Program Code: [(N/A)]- (N/A)

Recipient Organization
VIRGINIA POLYTECHNIC INSTITUTE
(N/A)
BLACKSBURG,VA 24061

Performing Department
Forest Resources and Environmental Conservation

Non Technical Summary
Managing forests for producingwood products and ecosystem services requires reliable models of tree growth and stand development. Forest stand dynamics are a function of the species present, the site quality, the degree to which the site is occupied, stand age, and management treatments. Quantification of site occupancy is central to developing reliable models for predicting forest growth and yield. Response to silvicultural treatments and the amount and size-class distribution of volume produced over time are closely related to competition for site resources (light, water, nutrients). Developing a more complete understanding of, and better quantitative expressions for, competition effects on tree growth and survival will further improve forest models and hencethe management of forest resources.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
123	0611	2090	100%

Knowledge Area
123 - Management and Sustainability of Forest Resources;

Subject Of Investigation
0611 - Conifer forests of the South;

Field Of Science
2090 - Statistics, econometrics, and biometrics;

Keywords

forest modeling

wood products

ecosystem services

plant competition

Goals / Objectives
The major goals of this project are to: 1) evaluate and improvecompetition indices used for predicting tree growth, 2) estimate the onset of competition effects on above-ground characteristics of trees in planted stands, 3) gain understanding and improve quantification of the roles of species, genotypes, site variability and climatic influences in competition relationships and tree-size distributions in forest stands, 4) improve ability to predict the outcomes of planting different genetic material and applying various silvicultural treatments which affect intra- and inter-specific competition in forest stands, and 5) Identify relevant hypotheses regarding competition processes over time in forest stands that might be evaluated with an experimental approach.

Project Methods
This project will use advanced modeling methodology to develop improved expressions of competition in forest populations. Modeling is a powerful tool for integrating and synthesizing existing theory and empirical evidence, identifying knowledge gaps, and suggesting relevant hypotheses regarding plant compeitition that might be tested through experimentation. Numerous measures of stand density and of point density have been promulgated, but none are entirely satisfactory. Hence, we will examine the components of competition, including resource depletion and preemption , as well as competitive effect and competitive response in order to better understand how trees in stands interact and to then formulate enhanced quantitative expressions for these competitive interactions. The modeling will be carried out using data from field studies that have been developed and maintained through the Forest Modeling Research Cooperative at Virginia Tech.

Progress 09/01/14 to 08/31/19

Outputs
Target Audience:We reached forest scientists, fellow researchers, and practicing professional foresters through publications, presentations, and workshops. We also mentored students and incorporated results into their courses. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students were mentored, research results were incorporated in undergraduate and graduate level courses, and workshops were conducted for professional foresters. How have the results been disseminated to communities of interest?Through annual meetings of the Forest Modeling Research Cooperative, presentations at meetings and workshops. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Improved competition indices for predicting tree growth were developed, tested and implemented. Understanding of when competition for growth resources in stands of trees becomes limiting was advanced. The role of genetic, site, and environmental influences in tree growth and stand development was elucidated. Guidelines for genetic selection and management inputs were improved. Hypotheses were formulated to guide future field-plot based research.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Allen, M.G., and H.E. Burkhart. 2019. Growth-density relationships in loblolly pine plantations. For. Sci. 65:250-264.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Green, P.C., S. Yang, and H.E. Burkhart. 2019. Comparison of plot- and stand-level projections of simulated loblolly pine (Pinus taeda) stands. Can. J. For, Res. 49:692-700.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Scolforo, H.F., J.P. McTague, H.E. Burkhart, J. Roise, J. McCarter, C.A. Alvares, and J.L. Stape. 2019. Stand-level growth and yield system for clonal eucalypt plantations in Brazil that accounts for water availability. For. Ecol. and Manage. 448:22-33.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Scolforo, H.F., J.P. McTague, H.E. Burkhart, J. Roise, O. Campoe, and J.L. Stape. 2019. Eucalyptus growth and yield system: Linking individual-tree and stand-level growth models in clonal eucalypt plantations in Brazil. For. Ecol. and Manage. 432:1-16.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Scolforo, H.F., J.P. McTague, H.E. Burkhart, J. Roise, O. Campoe, and J.L. Stape. 2019. Yield pattern of eucalypt clones across tropical Brazil: An approach to clonal grouping. For. Ecol. and Manage. 432:30-39.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Scolforo, H.F., J.P. McTague, H.E. Burkhart, J. Roise, C.A. Alvares, and J.L. Stape. 2019. Modeling whole-stand survival in clonal eucalypt stands in Brazil as a function of water availability. For Ecol. and Manage. 432:1002-1012.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Scolforo, H.F., J.P. McTague, H.E. Burkhart, J. Roise, R.L. Carneiro, and J.L. Stape. 2019. Generalized stem taper and tree volume equations applied to eucalyptus of varying genetics in Brazil. Can. J. For. Res. 49:447-462.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Yang, S., and H.E. Burkhart. 2019. Comparison of volume and stand table estimates with alternate methods for selecting measurement trees in point sampling. Forestry 92:42-51.
• Type: Books Status: Published Year Published: 2019 Citation: Burkhart, H.E., T.E. Avery, and B.P. Bullock. 2019. Forest Measurements. 6th Edition. Waveland Press, Long Grove, IL. 434 p.

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:We reached forest scientists, researchers, students, and practicing professional foresters through publications, presentations, and workshops. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate and graduate students were mentored as part of the project. How have the results been disseminated to communities of interest?The results have been distributed via meetings of the Society of American Foresters, the International Union of Forest Research Organizations and at the Annual Meeting of the Forest Modeling Research Cooperative. What do you plan to do during the next reporting period to accomplish the goals?We will continue collecting field data, analyzing data, preparing publications, and making presentations at scientific and professional meetings.

Impacts
What was accomplished under these goals? Six journal articles were published, talks on results from this project were presented at scienfiic and professional meetings, one workshop was conducted.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Bose, A.K., A, Weiskittel, C. Kuehne, R.G. Wagner, E. Turnblom, and H.E. Burkhart. 2018. Does commercial thinning improve stand-level growth of the three most commercially important softwood forest types in North America? For. Ecol. and Manage. 409: 683-693.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Scolforo, H.F., J.R.S. Scolforo, C.R. Thiersch, M.F. Thiersch, J.P. McTague, H.E. Burkhart, A.C.F. Filho, J.M. de Mello, and J.Roise. 2017. A new model of tropical tree diameter growth rate and its application to identify fast-growing native tree species. For. Ecol. and Manage. 400: 578-586.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Thomas, R.Q., E.B. Brooks, A.L. Jersild, E.J. Ward, R.H. Wynne, T.J. Albaugh, H. Dinon-Aldridge, H.E. Burkhart, J.-C. Domec, T.R. Fox, C.A. Gonzalez-Benecke, T.A. Martin, A. Noormets, D.A. Sampson, and R.O. Teskey. 2017. Leveraging 35 years of Pinus taeda research in the southeastern US to constrain forest carbon cycle predictions: regional data assimilation using ecosystem experiments. Biogeosciences 14: 3525-3547.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Yang, S., and H.E. Burkhart. 2018. Application of height-based and diameter-based relative spacing for estimation of stand basal area For. Sci. 64: 28-32.

Progress 10/01/16 to 09/30/17

Outputs
Target Audience:We reached forest scientists and practicing professional foresters through publications, presentations, and workshops. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate and graduate students and postdoctoral associates were mentored and provided opportunities for professonal growth. How have the results been disseminated to communities of interest?Through publications, presentations, and workshops. What do you plan to do during the next reporting period to accomplish the goals?Continue data collection, analyses, and dissemination of results through publications, presentations and workshops.

Impacts
What was accomplished under these goals? Data collection continued, analyses completed, publications submitted.

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: Albaugh, T.J., T.R. Fox, R.A. Rubilar, R.L. Cook, R.L. Amateis, and H.E. Burkhart. 2017. Post-thinning density and fertilization affect Pinus taeda stand and individual tree growth. For. Ecol. and Manage. 396:207-216.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Arias-Rodil, M., U. Di�guez-Aranda, and H.E. Burkhart. 2017. Effects of measurement error in total tree height and upper-stem diameter on stem volume prediction. For. Sci. 63:250-260.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Burkhart, H.E., A.M. Brunner, B.J. Stanton, R.A. Shuren, R.L. Amateis, and J.L. Creighton. 2017. An assessment of potential of hybrid poplar for planting in the Virginia Piedmont. New Forests. 48:479-490.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Scolforo, H.F., J.R.S. Scolforo, J.L. Stape, J.P. McTague, H.E. Burkhart, J. McCarter, F. Castro Neto, R.A. Loos, and R.C. Sart�rio. 2017. Incorporating rainfall data to better plan eucalyptus clones deployment in eastern Brazil. For. Ecol. and Manage. 391:145-153.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Yang, S. and H.E. Burkhart. 2017. Estimation of carrying capacity in loblolly pine (Pinus taeda L.) For. Ecol. and Manage. 385:167-176.

Progress 10/01/15 to 09/30/16

Outputs
Target Audience:We reached forest scientists and practicing professional foresters through publications, presentations, and workshops. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided research experience for graduate students and postdoctoral associates. How have the results been disseminated to communities of interest?Through publications, professional presentations, and workshops. What do you plan to do during the next reporting period to accomplish the goals?Continue anayzing data and preparing publications on findings.

Impacts
What was accomplished under these goals? Field measurements were continued, as scheduled. Data were analyzed, publications prepared, and graduate students conpleted degree programs.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Radtke P, Walker D, Frank J, Weiskittel A, DeYoung C, MacFarlane D, Domke G, Woodall C, Coulston J, Westfall J, 2016. Improved accuracy of aboveground biomass and carbon estimates for live trees in forests of the eastern United States. Forestry. doi:10.1093/forestry/cpw047
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Scolforo, HF, de Castro Neto, F, Scolforo, JRS, Burkhart, HE, et al. 2016. Modeling dominant height growth of eucalyptus plantations with parameters conditioned to climate variations. For. Ecol. and Manage. 380:182-195.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Thapa, R, Burkhart, HE, Li, J, Hong, Y. 2016. Modeling clustered survival times of loblolly pine with time-dependent covariates and shared frailties. J. Agric., Biol., and Env. Stat. 21:92-110
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Westfall JA, McRoberts RE, Radtke PJ, Weiskittel AR. 2016. Effects of uncertainty in upper-stem diameter information on tree volume estimates. Eur J. Forest. Res. 135:937-947.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Chen Q, McRoberts RE, Wang CW, Radtke PJ. 2016. Forest aboveground biomass mapping and estimation across multiple spatial scales using model-based inference. Remote Sensing of Environment 184:350-360.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Clough BJ, Russell MB, Domke GM, Woodall CW, Radtke PJ. 2016. Comparing tree foliage biomass models fitted to a multispecies, felled-tree biomass dataset for the United States. Ecol. Model. 333:79-91.

Progress 10/01/14 to 09/30/15

Outputs
Target Audience:We reached forestry scientists and practicing professional foresters through publications, presentations, and workshops. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has provided opportunities for graduate students and postdoctoral associates in measurement methods, analyses, and scientific literature evaluations. How have the results been disseminated to communities of interest?Through publications, professional presentations, and workshops. What do you plan to do during the next reporting period to accomplish the goals?Move forward with data analyses from the field measurements acquired during the dormant season 2015-16.

Impacts
What was accomplished under these goals? Additional measurements of ongoing field trials in planted loblolly pine stands are being taken during dormant season 2015-16. These measurements will facilitate analyses and progress in the major work goals of ths project.

Publications

• Type: Theses/Dissertations Status: Accepted Year Published: 2015 Citation: Huiquan Jiang, August, 2015. Incorporating Climate Sensitivity for Eastern United States Tree Species into the Forest Vegetation Simulator. Ph.D. Dissertation. Virginia Tech, Blacksburg, VA.
• Type: Theses/Dissertations Status: Accepted Year Published: 2015 Citation: Gavin R. Corral 2015. Quantifying and mapping spatial variability in simulated forest plots. Ph.D. Dissertation. Virginia Tech, Blacksburg, VA.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Gyawali, N and Burkhart, HE. 2015. General response functions to silvicultural treatments in loblolly pine plantations. Can. J. For Res. 45:252-265.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Thapa, R, Burkhart, HE. 2015. Modeling stand-level mortality of loblolly pine (Pinus taeda L.) using stand, climate and soil variables. For. Sci. 61:834-846.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Allen, MG, Burkhart, HE. 2015. A comparison of alternative data sources for modeling site index in loblolly pine plantations. Can. J. For. Res. 45:1025-1033.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Weiskittel AR, MacFarlane DW, Radtke PJ, Affleck DL, Hailemariam T, Woodall CW, Westfall JA, Coulston JW. 2015. A call to improve methods for estimating tree biomass for regional and national assessments. Journal of Forestry 113:414-424.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Jiang H, Radtke PJ, Weiskittel AR, Coulston JW, Guertin PJ. 2015. Climate- and soil-based models of site productivity in eastern US tree species. Canadian Journal of Forest Research 45:325-342.

Progress 09/01/14 to 09/30/14

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Graduate student applications for work on this project are being sought for academic year 2015-16. How have the results been disseminated to communities of interest? No new results from the first month of this project are yet available, but when significant results are obtained they will be submitted for publication and will be distributed to forest managers and forest landowners via extension and other outlets. What do you plan to do during the next reporting period to accomplish the goals? Graduate student theses and dissertation projects will be focused on the project goals, as well as addtional work that will be initiated by the project personnel.

Impacts
What was accomplished under these goals? This project was initiated in September 2014, so this report covers only one month of accomplishments. Work on goal 1, which consist of evaluating competition indices for use in tree growth prediction, is ongoing.

Publications