@article{shalizi_walker_heine_payn_isik_bullock_mckeand_2023, title={Performance Based on Measurements from Individual-Tree Progeny Tests Strongly Predicts Early Stand Yield in Loblolly Pine}, volume={2}, ISSN={["1938-3738"]}, url={https://doi.org/10.1093/forsci/fxad002}, DOI={10.1093/forsci/fxad002}, abstractNote={Abstract To facilitate the utility of genetic improvement in loblolly pine, individual-tree volume (productivity) scores estimated from single-tree plot or row-plot progeny test designs were compared with stand-level volume per unit area from block plots. A large number of families representing a wide range of progeny test scores for volume were established in growth and yield trials to generalize the results to families created by the breeding program. Individual-tree volume scores from progeny tests strongly corresponded with stand-level volume from block plots, especially after accounting for site quality and the risk of fusiform rust disease. A ten-point increase in the volume score from progeny test data was estimated to increase stand-level volume by 3.9 m3 ha-1 at age 6 years. A prediction model is presented that includes a new statistic, rust risk index, which is the expected rust incidence for a family at a new site when the hazard of rust for a checklot can be estimated from historical data. The study results through age 6 years corroborate the Performance Rating System as effective in guiding family deployment decisions. The models presented are based on pre-crown closure data at 6 years and will be updated with older measurements as the study matures. Study Implications: The Performance Rating System (PRS™) has been a successful tool for presenting genetic merit of improved loblolly pine families for landowners and forest managers in a more coherent and standardized manner. This system can be easily applied in other forest tree improvement programs, because it makes genetic improvement user-friendly for silviculturists and forest managers. Landowners can use this system to make decisions for selecting improved families suited to their specific forest management objectives. Seed orchard and nursery managers also depend on the PRS to choose the families to produce and as a third-party verification to market their genetic merit to customers. This study demonstrates that higher stand-level volume per unit area can be achieved when forest managers plant fast growing families with low fusiform rust disease risk on productive sites. The combined effect of genetic improvement for productivity and fusiform rust disease resistance is significant on stand-level volume per unit area.}, journal={FOREST SCIENCE}, author={Shalizi, Mohammad Nasir and Walker, Trevor D. and Heine, Austin J. and Payn, Kitt G. and Isik, Fikret and Bullock, Bronson P. and McKeand, Steven E.}, year={2023}, month={Feb} }
 @article{hall_stape_bullock_frederick_wright_scolforo_cook_2020, title={A Growth and Yield Model for Eucalyptus benthamii in the Southeastern United States}, volume={66}, ISSN={["1938-3738"]}, DOI={10.1093/forsci/fxz061}, abstractNote={Abstract In recent Eucalyptus cold-tolerance trials, E. benthamii has shown good growth rates as well as cold tolerance for USDA Plant Hardiness Zones 8 and 9. This study developed growth and yield models for E. benthamii in the southeastern United States. A network of 182 temporary sample plots of E. benthamii ranging in age from 1.5 to 13.3 years was established, and inventory data were collected. Site quality was determined by fitting a polymorphic site index curve, whereas a function for stand basal area based on age, dominant height, and site occupancy was fitted. Stand-level volume and dry-weight biomass prediction equations were fitted as a function of dominant height and basal area. Based on the growth and yield model results, mean annual increments ranged from 26.4 m3 ha–1 year–1 at rotation age 6 years on the best sites to 13.7 m3 ha–1 year–1 at rotation age 10 years on the poorest sites. This is the first published set of management-oriented models for land managers considering planting E. benthamii in the southeastern United States.}, number={1}, journal={FOREST SCIENCE}, author={Hall, Kevin B. and Stape, J. L. and Bullock, Bronson P. and Frederick, Doug and Wright, Jeff and Scolforo, Henrique F. and Cook, Rachel}, year={2020}, month={Feb}, pages={25–37} }
 @article{walker_bullock_smith_mckeand_2020, title={Modeling Self-Thinning Patterns in Loblolly Pine with Provenance and Family Effects}, volume={66}, ISSN={["1938-3738"]}, url={https://doi.org/10.1093/forsci/fxaa030}, DOI={10.1093/forsci/fxaa030}, abstractNote={Abstract Size-density trajectories and self-thinning boundary lines were modeled for two diverse provenances of Pinus taeda L. and five open-pollinated families within each provenance. The data used come from a single site with replicated 64-tree block plots measured through age 25 years. The effects of provenance and family were tested using linear and nonlinear mixed-effects self-thinning models. The drought-hardy Lost Pines of Texas provenance displayed a greater predicted carrying capacity (almost 200 more trees per hectare at reference diameter 25.4 cm) and had a more abrupt approach to the self-thinning line than the widely planted Atlantic Coastal Plain provenance. However, the growth rate of the Lost Pines of Texas provenance was considerably slower and stem form was unacceptable for timber production. Families from the Atlantic Coastal Plain differed in their maximum stand density index predictions (from 1,118 to 1,282 trees per hectare at the reference diameter), suggesting there is an opportunity for artificial selection to change maximum stand density index in this breeding population of loblolly pine. A novel method for predicting the self-thinning boundary line using random effects inherent to the experimental design is presented and recommended for repeated measures data. Experimental design considerations for evaluating genetic differences in self-thinning are discussed. Study Implications Genetic improvement of growth rate in forest trees has resulted in large gains in plantation productivity, but the effect on carrying capacity has not been addressed. This study indicated that artificial selection on tolerance to competition in the widely planted Atlantic Coastal Plain provenance of loblolly pine can potentially increase harvest yield without sacrificing growth rate. The drought-hardy Lost Pines of Texas provenance displayed greater carrying capacity but had poor stem form and slow growth. The Lost Pines provenance may be attractive for aboveground carbon sequestration, since it sustained substantially more biomass because of greater maximum stand density and denser wood.}, number={6}, journal={FOREST SCIENCE}, publisher={Oxford University Press (OUP)}, author={Walker, Trevor D. and Bullock, Bronson P. and Smith, Benjamin C. and McKeand, Steven E.}, year={2020}, month={Dec}, pages={712–725} }
 @article{denham_coyle_oishi_bullock_heliovaara_novick_2019, title={Tree resin flow dynamics during an experimentally induced attack by Ips avulsus, I. calligraphus, and I. grandicollis}, volume={49}, ISSN={["1208-6037"]}, DOI={10.1139/cjfr-2018-0024}, abstractNote={The success of tree colonization by bark beetles depends on their ability to overcome host tree defenses, including resin exudation and toxic chemicals, which deter bark beetle colonization. Resin defenses during insect outbreaks are challenging to study in situ, as outbreaks are stochastic events that progress quickly and thus preclude the establishment of baseline observations of non-infested controls. We use synthetic aggregation pheromones to demonstrate that confined Ips bark beetle herbivory can be successfully initiated to provide opportunities for studying interactions between bark beetles and their hosts, including the dynamics of constitutive and induced resin exudation. In Pinus taeda L. plantations between 12 and 19 years old in North and South Carolina, U.S., trees were affixed with pheromone lures, monitored for evidence of bark beetle attacks, and resin samples were collected throughout the growing season. Baiting increased beetle herbivory to an extent sufficient to produce an induced resin response. Attacked trees exuded about three times more resin at some time than control trees. This supports previous work that demonstrated that information on constitutive resin dynamics alone provides an incomplete view of a host tree’s resistance to bark beetle attack.}, number={1}, journal={CANADIAN JOURNAL OF FOREST RESEARCH}, author={Denham, Sander O. and Coyle, David R. and Oishi, A. Christopher and Bullock, Bronson P. and Heliovaara, Kari and Novick, Kimberly A.}, year={2019}, month={Jan}, pages={53–63} }
 @article{wood_bullock_isik_mckeand_2015, title={Variation in Stem Taper and Growth Traits in a Clonal Trial of Loblolly Pine}, volume={61}, ISSN={["1938-3738"]}, DOI={10.5849/forsci.12-068}, abstractNote={As volume is the primary measure of value in loblolly pine (Pinus taeda L.) stands, knowledge about the stem taper of commonly deployed clones may better describe genetic gains made by each clonal variety and could provide more accurate volume estimates. Clonal varieties with combined low taper and fast growth can potentially offer great gains in uniformity, quality, and volume when deployed operationally. Clones propagated via somatic embryogenesis from 13 full-sib families and two open-pollinated families were measured in the eighth growing season across three sites in coastal Georgia and South Carolina. Three form quotients were used to analyze stem taper differences among clones and to assess taper impacts on total stem volume. Significant clonal variation was found for form quotients, indicating that genetic differences exist in stem taper among different clones. Clone mean heritability estimates for form quotients and growth traits were moderate to high (0.64–0.94), indicating that the use of form quotients could improve selection by accounting for taper in clones. However, taper impacts on total volume were minimal after accounting for dbh and total height, and differences among clones in total volume were sufficiently captured using a single combined-variable D2H equation. While selecting clones by total height and dbh may not necessarily capture clones with the least taper, this method was sufficient for selecting varieties with the largest volumes.}, number={1}, journal={FOREST SCIENCE}, publisher={Oxford University Press (OUP)}, author={Wood, Elizabeth R. and Bullock, Bronson P. and Isik, Fikret and McKeand, Steven E.}, year={2015}, month={Feb}, pages={76–82} }
 @article{green_bullock_2014, title={Assessing Sampling and Model Error in Standing Green Weight Estimation for a Loblolly Pine Plantation}, volume={60}, ISSN={["1938-3738"]}, DOI={10.5849/forsci.13-007}, abstractNote={A simple study was designed to assess the magnitude of model error in estimates of total green weight per acre in a sample loblolly pine plantation. A model was fitted to a large felled-tree data set and used to predict weight per ha in the sample stand. This is a simple case and, even here, ignoring model error would result in confidence intervals on the order of 10–40% too narrow.}, number={4}, journal={FOREST SCIENCE}, author={Green, Edwin J. and Bullock, Bronson}, year={2014}, month={Aug}, pages={623–627} }
 @article{smith_bullock_isik_mckeand_2014, title={Modeling genetic effects on growth of diverse provenances and families of loblolly pine across optimum and deficient nutrient regimes}, volume={44}, ISSN={["1208-6037"]}, url={http://dx.doi.org/10.1139/cjfr-2013-0379}, DOI={10.1139/cjfr-2013-0379}, abstractNote={Optimal deployment of improved loblolly pine (Pinus taeda L.) planting stock in the southeastern United States requires knowing how diverse seed sources and families perform over time across the wide range of sites used for plantations. This study tests if the relative growth performance of provenances and families is the same at the individual-tree and stand levels for family block plantings and determines what type of adjustment may be required to account for genetic differences when modeling growth and yield. Ten open-pollinated families from two very different provenances, Atlantic Coastal Plain and “Lost Pines” Texas, were grown in single-family block plots to test for growth differences between provenances and among families under severely deficient and optimal nutrition regimes on a nutrient-deficient, dry site. The three-parameter Chapman–Richards function was fit to plot means over time by provenance, family, and nutrition treatments. Models with provenance- or family-specific parameters of the Chapman–Richards function were tested for significant improvement over global parameters. At age 14 years, family, provenance, and nutrition treatments all significantly affected individual-tree growth traits of height, diameter, and volume. Significant nutrition by provenance interactions were found for stand-level traits of basal area per hectare and volume per hectare. Family differences were also significant for these traits. Provenance- or family-specific asymptotic parameters accounted for differences in growth over time. Several traits required the use of local asymptotic and rate parameters in the fertilized treatment only. For modeling growth, a multiplier would be sufficient to account for genetic effects on the majority of traits.}, number={11}, journal={CANADIAN JOURNAL OF FOREST RESEARCH}, publisher={Canadian Science Publishing}, author={Smith, Ben C. and Bullock, Bronson P. and Isik, Fikret and McKeand, Steven E.}, year={2014}, month={Nov}, pages={1453–1461} }
 @article{alvarez_allen_albaugh_stape_bullock_song_2013, title={Factors influencing the growth of radiata pine plantations in Chile}, volume={86}, DOI={10.1093/forestry/cps072}, abstractNote={We examined environmental factors affecting growth rates of Pinus radiata in Chile. The relationships between annual volume growth and soil, climate, canopy and stand factors were analysed using data from 48 permanent sample plots in P. radiata plantations in central Chile. Water availability (as affected by precipitation, soil water holding capacity and potential evapotranspiration) appeared to be the factor most limiting to leaf area and growth. Maximum growing season temperature also negatively affected growth. Sites with the highest productivities had the lowest annual water deficits. The most productive sites used water and light more efficiently. Growth per unit of potential evapotranspiration ranged from 0.5 to 1.6 kg of wood per m3 of water and growth per unit of radiation ranged from 0.3 to 0.5 g of wood per MJ of photosynthetically active radiation for low and high productivity sites. The inclusion of simple climatic variables such as maximum temperature and precipitation into Chilean P. radiata growth and yield models should improve their performance.}, number={1}, journal={Forestry}, author={Alvarez, J. and Allen, Howard and Albaugh, T. J. and Stape, J. L. and Bullock, B. P. and Song, C.}, year={2013}, pages={13–26} }
 @article{aspinwall_king_mckeand_bullock_2011, title={Genetic effects on stand-level uniformity and above- and belowground dry mass production in juvenile loblolly pine}, volume={262}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2011.04.029}, abstractNote={Abstract Genetic differences in stand-level above- and belowground dry mass production in loblolly pine (Pinus taeda L.) may influence southern pine plantation productivity, sustainability and carbon (C) sequestration. Furthermore, deployment of more or less genetically homogeneous individuals could impact stand uniformity and ecosystem processes. In this study, we aimed to compare stand uniformity and above- and belowground dry mass production among loblolly pine genotypes of contrasting inherent genetic homogeneity. We hypothesized that stand-level uniformity would increase as within-genotype inherent genetic variation decreased (open-pollinated (half-sib) > full-sib > clone). To examine genetic effects on stand uniformity and productivity, we grew ten different genotypes (three open-pollinated families, three full-sib families, three clones, and one seed orchard mix variety) in a plantation setting for 4 years, at two different planting densities (∼539 and 1077 trees ha−1), and used allometric relationships to estimate standing dry mass and annual dry mass production. In the low planting density treatment, age 3 total standing dry mass of the most productive genotype (5824 kg ha−1) was 82% higher than that of the least productive genotype (3207 kg ha−1). In the high planting density treatment, age 3 total standing dry mass of the most productive genotype (11,393 kg ha−1) was 110% higher than that of the least productive genotype (5427 kg ha−1). Genetic differences in annual dry mass production were of a similar magnitude with peak rates during the third year as high as 4221 and 8198 kg ha−1 yr−1 in the low and high planting density treatments, respectively. More genetically homogeneous genotypes did not show greater stand-level uniformity under operational management conditions. Over time, genotypes showed no consistent differences in the coefficient of variation (CV) for ground-level diameter; however, two full-sib and two half-sib families showed significantly lower CV’s for total tree height than all three clones. Moreover, genotypes with lower CV’s for height growth displayed greater stand-level dry mass production which supports the premise that greater stand uniformity will lead to enhanced productivity. Since uniformity and stand-level productivity of loblolly pine clones will be principally governed by environmental heterogeneity, our results highlight the need for silvicultural prescriptions that maximize site uniformity. In addition, our results demonstrate how the deployment of highly productive loblolly pine genotypes may provide a means of enhancing southern pine ecosystem sustainability by sequestering C in both harvestable aboveground biomass and woody belowground biomass.}, number={4}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Aspinwall, Michael J. and King, John S. and McKeand, Steven E. and Bullock, Bronson P.}, year={2011}, month={Aug}, pages={609–619} }
 @article{sherrill_bullock_mullin_mckeand_purnell_2011, title={Total and merchantable stem volume equations for midrotation loblolly pine (Pinus taeda L.)}, volume={35}, number={3}, journal={Southern Journal of Applied Forestry}, author={Sherrill, J. R. and Bullock, B. P. and Mullin, T. J. and McKeand, S. E. and Purnell, R. C.}, year={2011}, pages={105–108} }
 @article{eckard_isik_bullock_li_gumpertz_2010, title={Selection efficiency for solid wood traits in pinus taeda using time-of-flight acoustic and micro-drill resistance methods}, volume={56}, number={3}, journal={Forest Science}, author={Eckard, J. T. and Isik, F. and Bullock, B. and Li, B. L. and Gumpertz, M.}, year={2010}, pages={233–241} }
 @article{jackson_pittillo_allen_wentworth_bullock_loftis_2009, title={Species Diversity and Composition in Old Growth and Second Growth Rich Coves of the Southern Appalachian Mountains}, volume={74}, ISSN={["1938-4386"]}, DOI={10.2179/07-017.1}, abstractNote={Because of ongoing debate over the long term impacts of logging, we conducted a study to assess if second growth (70 ± 10 years) rich coves differ from old growth rich coves (> 125 years) in species diversity or composition. We sampled twenty-six 0.1 ha plots, representing these two age classes. We distributed the plots amongst three randomly selected mountain ranges in the southern Appalachians of North Carolina, and sampled each mountain range in separate years. We used nested subplots of 0.01 m2, 0.1 m2, 1 m2, 10 m2, 100 m2, and 1000 m2 to establish species-area relationships (SARs) for each age class. We found no significant differences between the SARs for the two age classes, nor did we find significant differences between age classes using the Simpson, Shannon-Wiener, or Sorensen indices of species diversity. However, we found that total cover of all plant species was greater in old growth rich coves, and that 10% of the tested species had lower abundance in second growth. No species were present in old growth and absent in second growth, but species with lower second growth abundance may warrant future study.}, number={1}, journal={CASTANEA}, author={Jackson, B. Clay and Pittillo, J. Dan and Allen, H. Lee and Wentworth, Thomas R. and Bullock, Bronson P. and Loftis, David L.}, year={2009}, month={Mar}, pages={27–38} }
 @article{sherrill_mullin_bullock_mckeand_purnell_gumpertz_isik_2008, title={An evaluation of selection for volume growth in loblolly pine}, volume={57}, ISSN={["2509-8934"]}, DOI={10.1515/sg-2008-0004}, abstractNote={Abstract Total inside-bark volume is the most important selection criterion for productivity in tree breeding programs in the Southeastern U.S. Tree breeders typically estimate total inside-bark volume based on outside-bark diameter at breast height and total height without accounting for stem taper or bark thickness. To make a direct determination of total inside- and outside-bark volume, a loblolly pine (Pinus taeda L.) open-pollinated family trial replicated with cultural treatments of weed control and fertilization was measured. This direct measurement was compared to typical volume estimates. In this trial, approximately 40 individuals from each of 25 open-pollinated first- and second-generation families were destructively sampled in the 13 th growing season. Selection for volume using a combined-variable (diameter 2 * height) equation was found to be highly effective for making volume gain. There was a high correlation between estimated and directly-measured total inside-bark volumes (0.99). Bark thickness and stem taper had low importance for stem volume selection. There was a positive genetic correlation between bark thickness and diameter at breast height (0.66). This indicates that selection for larger diameters may produce individuals with thicker bark, which may eventually affect total inside-bark volume estimates.}, number={1}, journal={SILVAE GENETICA}, author={Sherrill, J. R. and Mullin, T. J. and Bullock, B. P. and McKeand, S. E. and Purnell, R. C. and Gumpertz, M. L. and Isik, F.}, year={2008}, pages={22–28} }
 @article{boone_bullock_2008, title={Spatial correlation matrix selection using Bayesian model averaging to characterize inter-tree competition in loblolly pine trees}, volume={35}, ISSN={["0266-4763"]}, DOI={10.1080/02664760802185845}, abstractNote={Many applications of statistical methods for data that are spatially correlated require the researcher to specify the correlation structure of the data. This can be a difficult task as there are many candidate structures. Some spatial correlation structures depend on the distance between the observed data points while others rely on neighborhood structures. In this paper, Bayesian methods that systematically determine the ‘best’ correlation structure from a predefined class of structures are proposed. Bayes factors, Highest Probability Models, and Bayesian Model Averaging are employed to determine the ‘best’ correlation structure and to average across these structures to create a non-parametric alternative structure for a loblolly pine data-set with known tree coordinates. Tree diameters and heights were measured and an investigation into the spatial dependence between the trees was conducted. Results showed that the most probable model for the spatial correlation structure agreed with allometric trends f...}, number={9}, journal={JOURNAL OF APPLIED STATISTICS}, author={Boone, Edward L. and Bullock, Bronson P.}, year={2008}, pages={967–977} }
 @article{bullock_boone_2007, title={Deriving tree diameter distributions using Bayesian model averaging}, volume={242}, ISSN={["0378-1127"]}, DOI={10.1016/j.foreco.2007.01.024}, abstractNote={Diameter distributions of loblolly pine trees (Pinus taeda L.) were derived using Bayesian methods. The Bayesian derived distributions were compared to traditional maximum likelihood techniques for estimating diameter distributions. The data for this study come from a planting density study established in 1983 at four locations in Virginia and North Carolina. Results of the Bayesian analysis show that different distributional forms had the highest posterior probability at different ages for the diameter distributions. Standard goodness-of-fit statistics for the maximum likelihood estimates did not consistently recommend a distribution for the empirical data. Further, there were cases where no distribution was chosen from the candidate distributions based on the goodness-of-fit statistics. The lack of a clear distribution that fits over the range of ages for the diameter data suggests that a Bayesian model averaging technique would be beneficial for deriving tree diameter distributions with probability proportional to the posterior distribution. A simulation study was conducted to compare the goodness-of-fit statistics from the averaged distributional model and other candidate distributions. Results indicated that the averaged distribution had superior goodness-of-fit values over the candidate models; the exception being when the candidate distribution was an exact fit to the data.}, number={2-3}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Bullock, Bronson P. and Boone, Edward L.}, year={2007}, month={Apr}, pages={127–132} }
 @inproceedings{eckard_isik_bullock_2006, title={Prediction of whole-stem solid wood properties of superior loblolly pine clones for deployment}, volume={40}, booktitle={Information Exchange Group 40 Conference, Incorporating Genetic Advances into Forest Productivity Systems: Value for All Landowners}, author={Eckard, J. T. and Isik, F. and Bullock, B. P.}, year={2006}, pages={25} }
 @article{bullock_burkhart_2005, title={An  evaluation of spatial dependency in juvenile loblolly pine stands using stem diameter}, volume={51}, number={2}, journal={Forest Science}, author={Bullock, B. P. and Burkhart, H. E.}, year={2005}, pages={102–108} }
 @inproceedings{smith_bullock_mckeand_2005, title={Comparing parameter estimation techniques for diameter distributions of loblolly pine}, booktitle={Proceedings of the 28th Southern Forest Tree Improvement Conference}, author={Smith, B. C. and Bullock, B. P. and McKeand, S. E.}, year={2005}, pages={104–106} }
 @article{bullock_burkhart_2005, title={Juvenile diameter distributions of loblolly pine characterized by the two-parameter Weibull function}, volume={29}, ISSN={["0169-4286"]}, DOI={10.1007/s11056-005-5651-5}, number={3}, journal={NEW FORESTS}, author={Bullock, BP and Burkhart, HE}, year={2005}, month={May}, pages={233–244} }
 @inproceedings{sherrill_mullin_bullock_mckeand_purnell_gumpertz_2005, title={Total inside-bark volume estimation for loblolly pine (Pinus taeda L.) in genetic trials}, booktitle={Proceedings of the 28th Southern Forest Tree Improvement Conference}, author={Sherrill, J. R. and Mullin, T. J. and Bullock, B. P. and McKeand, S. E. and Purnell, R. C. and Gumpertz, M. L.}, year={2005}, pages={123–125} }
 @inproceedings{mckeand_grissom_allen_bullock_2004, title={Ten-year response of diverse families of loblolly pine to fertilization}, booktitle={Forest Genetics and Tree Breeding in the Age of Genomics: Progress and Future,  IUFRO Joint Conference of Division 2, Conference Proceedings}, author={McKeand, S. E. and Grissom, J. E. and Allen, H. L. and Bullock, B. P.}, editor={Li, B. and McKeand, S.Editors}, year={2004}, pages={453–455} }
 @article{bullock_burkhart_2003, title={Equations for predicting green weight of loblolly pine trees in the South}, volume={27}, number={3}, journal={Southern Journal of Applied Forestry}, author={Bullock, B. P. and Burkhart, H. E.}, year={2003}, pages={153–159} }