Pinus Echinata Mill Research Articles

An Annual basal area growth model with multiplicative climate modifier fitted to longitudinal data for shortleaf pine

Abstract Understanding climatic influences on annual basal area growth (ABAG) rates of individual trees is necessary to predict future stand dynamics. We fitted nonlinear ABAG models for shortleaf pine (Pinus echinata Mill.) with climate variables linearly added to the arguments of logistic and exponential multiplicative functions of climate variables as climate modifiers to incorporate 14 growing seasons and 30 month-specific climate variables including standardized precipitation index. Data were collected from permanently established plots in Arkansas and Oklahoma. Six re-measurement events collected between 1985 and 2014 provided five growth periods (GPs) and ABAG models were fitted using a mixed-effects approach. Model performance was evaluated using likelihood ratio tests and fit statistics. Climate variables from GPs expressed as deviations from long-term means that performed better than other candidate variables included (1) month-specific: June mean maximum air temperature (°C) (DTMAX6), and September precipitation (mm) (DPPT9); and (2) growing seasons: mean maximum air temperature (°C) (DGTMAX) and precipitation (mm) (DGPPT). ABAG models fitted with multiplicative climate modifiers provided improved growth predictions compared with models fitted with climate variables linearly added to the argument of a logistic function. There was positive correlation with DGTMAX and negative correlation with DMPPT. In addition, 1°C increase in mean maximum temperature had a greater cumulative effect on ABAG rates of young versus old trees. Fitting ABAG models with climate modifiers are useful for assessing variations in productivity due to climate change in the future.

Resinosis Inhibits Monochamus spp. (Coleoptera: Cerambycidae) Colonization of Healthy Shortleaf Pines in Southeastern United States.

The genus Monochamus Dejean (Coleoptera: Cerambycidae) includes large, woodboring, longhorned beetles, which colonize pine trees in North America. Many authors have classified the genus as saprophagous, but one recent study reported successful colonization of standing jack pine trees (Pinus banksiana Lamb.) (Pinales: Pinaceae) following severe wind disturbance in Minnesota. We tested whether two Monochamus species native to the southeastern United States (M. titillator (Fabricius) and M. carolinensis (Olivier)) could successfully colonize healthy shortleaf pines (Pinus echinata Mill.) (Pinales: Pinaceae) in recently harvested stands without coincident abiotic or biotic stressors, such as lightning strikes or bark beetle attacks. We attached commercially available semiochemical lures, including monochamol, ethanol, and ipsenol, to healthy shortleaf pine trees and observed Monochamus spp. oviposition response. Egg development was monitored following oviposition by harvesting attacked trees and dissecting oviposition pits. High numbers of oviposition pits were observed on trees treated with lures containing the bark beetle pheromone ipsenol and pits were highly concentrated on the tree bole near lures. Although egg deposition occurred, pit dissection revealed large amounts of resin present in almost all dissected pits and that egg hatch and subsequent larval development were rare. Our results demonstrate that southeastern Monochamus spp. are unlikely to be primary pests of healthy shortleaf pines due to resinosis. To better understand the host finding behavior of these two Monochamus species, we also conducted trapping trials with several semiochemical combinations. Both species and sexes demonstrated similar attraction to compounds, and the most attractive lure combined host volatiles, pheromone, and sympatric insect kairomone.

Determining unthinned shortleaf pine (Pinus echinata Mill.) plantation economic rotation ages in the Western Gulf

Shortleaf pine Pinus echinata Mill has been planted in the Western Gulf region The Forest Vegetation Simulator FVS is the only widely available comprehensive yield prediction system for these plantations Predictions from the time ndash of ndash planting were obtained for densities of and for site indexes of and ft base age Based on verification analyses conducted using observed yields from other studies FVS projections conducted from the time ndash of ndash planting are relatively low Hence additional verification analyses were made based on reported diameter distribution and associated height data in year old plantations ldquo Calibrated rdquo projections were then made for ages ranging from to In general if plot data are available allowing FVS to be ldquo calibrated rdquo to local site conditions much more accurate predictions will be produced In terms of economics given current markets economic rotation ages are generally around to years For low quality sites e g site index ft financial returns will likely not be positive and hence on these lower quality sites an ecologically based management regime may be better

First-Year Vitality of Reforestation Plantings in Response to Herbivore Exclusion on Reclaimed Appalachian Surface-Mined Land

Conventional Appalachian surface-mine reclamation techniques repress natural forest regeneration, and tree plantings are often necessary for reforestation. Reclaimed Appalachian surface mines harbor a suite of mammal herbivores that forage on recently planted seedlings. Anecdotal reports across Appalachia have implicated herbivory in the hindrance and failure of reforestation efforts, yet empirical evaluation of herbivory impacts on planted seedling vitality in this region remains relatively uninitiated. First growing-season survival, height growth, and mammal herbivory damage of black locust (Robinia pseudoacacia L.), shortleaf pine (Pinus echinata Mill.), and white oak (Quercus alba L.) are presented in response to varying intensities of herbivore exclusion. Seedling survival was generally high, and height growth was positive for all species. The highest herbivory incidence of all tree species was observed in treatments offering no herbivore exclusion. While seedling protectors lowered herbivory incidence compared with no exclusion, full exclusion treatments resulted in the greatest reduction of herbivore damage. Although herbivory from rabbits, small mammals, and domestic animals was observed, cervids (deer and elk) were responsible for 95.8% of all damaged seedlings. This study indicates that cervids forage heavily on planted seedlings during the first growing-season, but exclusion is effective at reducing herbivory.

Comparison of biomass partitioning and transpiration for water-stressed shortleaf, loblolly, and shortleaf × loblolly pine hybrid seedlings

Hybridization between shortleaf pine (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.) has dramatically increased and may threaten the genetic integrity of shortleaf pine. Shortleaf pine is presumed to be more drought tolerant than loblolly pine, but the drought hardiness of the hybrid pine is not known. We determined biomass partitioning in response to water stress and measured whole-plant transpiration of shortleaf, loblolly, and hybrid pine seedlings. Water stress decreased total seedling biomass, increased biomass partitioning to foliage, and decreased biomass partitioning to coarse roots. Shortleaf pine seedlings partitioned more biomass to coarse roots than loblolly pine, and hybrid pine was intermediate between the parent species. We found no differences in the level of soil moisture at which seedlings of different species began to limit transpiration. Our results suggest that the transpiration response of shortleaf pine and hybrid pine is similar to that of loblolly pine when exposed to water stress. However, greater partitioning to coarse root may allow shortleaf and hybrid pines to better withstand drought due to greater potential belowground carbohydrate supply.

Mortality, scarring, and growth in an oak woodland following prescribed fire and commercial thinning in the Ozark Highlands

Oak-dominated (Quercus Spp.) woodlands are commonly thinned and burned in the Ozark Highlands to prevent canopy closure and regenerate desired species, despite a lack of information regarding tree mortality, scarring, and growth in residual stands. Our study compared stand- and tree-level responses after two prescribed burns across four treatments: control, burn, thin, and thin+burn. Results showed that two prescribed fires led to 19% greater cumulative mortality than in unburned stands. In the burn treatment, 19.3% of residual live overstory trees were scarred, compared to 32.4% of trees in the thin+burn treatment. Analysis of scar area revealed that thinning before burning significantly increased the surface area (cm2) of fire scars. In general, trees in the red oak group (Erythrobalanus spp.) had the greatest percentage of scarred trees, followed by the white oak group (Leucobalanus spp.), hickories (Carya spp.), and shortleaf pines (Pinus echinata Mill.). Our data indicate that two fires did not significantly decrease the radial growth of white oaks, except in stands which were thinned prior to prescribed burns. Average percent change in ring-widths (mm) suggest a 1.9% growth decrease in control, 1.4% decrease in burn, 84% increase in thin, and a 35% increase in thin+burn. Covariates such as age, slope, surrounding basal area, canopy openness, and fire scars were analyzed, but tree diameter was the only significant predictor of growth response. Overall, results suggest that effects of prescribed burning are more pronounced in thinned stands as a function of increased fuel loads and fire intensity, causing greater mortality, fire scarring, and reductions in potential growth than fire or thinning alone. This study highlights important tradeoffs between prescribed fire and thinning in oak dominated ecosystems, especially where fire related damages are in potential conflict with other stand objectives.

The genetics of shortleaf pine (Pinus echinata mill.) with implications for restoration and management

Shortleaf pine (Pinus echinata Mill.) is an important commercial timber resource and forest ecosystem component in the southeastern USA. The species occurs in mainly drier sites as an early- to mid-successional species, is fire-adapted, and it plays an important role in the fire ecology of the region. However, shortleaf pine genetics are not well-studied, especially in this era of molecular genetics and genomics. Most genetics research about the species has focused on provenance testing. Generally, shortleaf pine performs well in colder areas, when compared to loblolly pine (Pinus taeda L.), a close relative, which is faster growing and the most common plantation species in the region. Though not as advanced in genetic improvement as loblolly pine, tree breeders have improved shortleaf pine in one to two generations of selection, and diverse, genetically improved shortleaf pine materials are available to foresters and landowners throughout the southeastern USA. Researchers have also studied the genetic variation of shortleaf pine using various molecular markers and have found that shortleaf pine is generally a prolific outcrosser, a trait it shares with other non-isolated members of the family Pinaceae. In recent years, however, it has shared less genetic material across long ranges, probably because of habitat fragmentation. Various anthropogenic factors also affect shortleaf pine’s future, as recent studies show that shortleaf pine introgression with loblolly pine puts the species—and the resiliency of southeastern forests—at risk. Importantly, fire exclusion is a likely cause of the increase in introgression. Herein, we provide further details and up-to-date genetic information and resources for foresters and ecologists interested in the restoration and management of shortleaf pine.

Using quadratic mean diameter and relative spacing index to enhance height–diameter and crown ratio models fitted to longitudinal data

The inclusion of quadratic mean diameter (QMD) and relative spacing index (RSI) substantially improved the predictive capacity of height–diameter at breast height (d.b.h.) and crown ratio models (CR), respectively. Data were obtained from 208 permanent plots established in western Arkansas and eastern Oklahoma during 1985–1987 and remeasured for the sixth time (2012–2014). Existing height–d.b.h. and CR estimation models for naturally occurring shortleaf pine forests (Pinus echinata Mill.) were updated and modified for improved performance. Additionally, eight height–d.b.h. relationship models that use only d.b.h. (fundamental local models) were modified using covariates. The model performance was evaluated using fit statistics [root mean square error (RMSE), Fit index and Akaike information criteria (AIC)]. The results showed that the best model form which was an extended non-linear model with autoregressive first order AR (1) structure and power variance function performed better than extended mixed-effects models and predicted well as an ordinary least squares non-linear model. The autocorrelation within individual trees was larger for the height–d.b.h. relationship than for CR estimation. The addition of QMD to mean dominant height (HD) greatly improved height–d.b.h. relationship with a reduction of 8 per cent in RMSE, compared with the use of basal area per hectare. Similarly, multiplying a fundamental local model by using QMD raised to a parametric power reduced RMSE by 16 per cent, improved Fit index by 12 per cent and decreased the AIC value by 7 per cent. D.b.h., HD and RSI best explained the crown ratio relationship with an improved Fit index by 6.7 per cent compared with alternative non-linear models without RSI. The logistic model for CR also provided prediction accuracy similar to that of a commonly used non-linear model. A non-linear model with an application of remedial measures to enhance adherence to modelling assumptions can provide better parameter estimates than mixed-effects modelling approach.

The Silvicultural Implications of Age Patterns in Two Southern Pine Stands after 72 Years of Uneven-Aged Management

A randomized sample of 250 loblolly (Pinus taeda L.) and shortleaf (Pinus echinata Mill.) pine ring counts was collected from the Good and Poor Farm Forestry compartments on the Crossett Experimental Forest. These mature, pine-dominated stands have been managed using uneven-aged silviculture since 1937. Our sample shows that both of these compartments have many different age classes although few distinct cohorts. Over the decades, pine recruitment followed the dozens of timber harvests and occasional natural mortality events (e.g., lightning strikes, ice storms, windthrow, insects, and disease). After more than 70 years of active management, only 5% of the overstory pines are shortleaf and about 6% of all pines originated before the imposition of uneven-aged silviculture. The age structure of these stands can be used to adapt conventional silvicultural treatments. For example, a wide range of ages was found in the sawtimber size classes, indicating that productivity improvements are still possible. The data also suggest that it may be possible to modify current practices to alter the age structure to favor other kinds of ecosystem services (e.g., wildlife habitat).

Historic Fire and Canopy Disturbance Dynamics in an Oak-Pine (Quercus-Pinus) Forest of the Missouri Ozarks (1624–2010)

ABSTRACT Studies of historic forest disturbances provide an important context for the ecological dynamics that affect forest structure and successional trajectory. Previous historical disturbance research in the Missouri Ozark Highlands has highlighted the dynamics of fire regimes. However, little is known concerning canopy disturbance regimes in this region. The primary objective of this study was to reconstruct the history of multiple disturbances at a site that was known for having both historic Native and Euro-American activity. We analyzed the radial growth of shortleaf pine (Pinus echinata Mill.) and white oak (Quercus alba L.) to infer growth release events and documented historic fire events based on fire-scarred P. echinata. The majority of trees (87%) exhibited at least one growth release between 1624 and 2000 with the earliest growth release occurring in 1645. A total of 39 fires were documented between 1706 and 1915. Mean duration of growth releases for both species was approximately six years...

Structure and Dynamics of an Old-Growth Pine-Oak Community in the Southern Appalachian Mountains, Georgia, U.S.A.

Investigando la composición y estructura de los bosques de viejo crecimiento proporciona información acerca de la variabilidad espacial y temporal de los procesos responsables de desarrollo del rodal, la sucesión y los patrones biogeográficos de los bosques. Este estudio cuantifica la estructura rodal en la reserva de bosque Marshall, un remanente de bosque de viejo crecimiento situada en el noroeste de Georgia. Establecimos parcelas de inventario forestal para cuantificar la composición de especies, la estructura rodal y la dinámica sucesional. También analizamos los patrones de crecimiento radial de los árboles para documentar la edad del rodal, el reclutamiento y la frecuencia de perturbación del dosel dentro de la reserva. El bosque era dominó por el pino de hoja corta (Pinus echinata Mill.) y el castaño de roble (Quercus montana Willd.), mientras que el arce rojo (Acer rubrum L.) y la nuez dura de mockernut (Carya tomentosa Nutt.) eran abundantes en el sotobosque. Pino de hoja corta fue la especie de árbol más antiguo en la reserva, con los mas viejos excediendo 220 años de edad. Un patrón sucesional clara desarrolló sobre del siglo 20 con el establecimiento de la nuez dura y arce después de pino y roble. El agente principal de perturbación del dosel en el siglo 20 fue tormentas de hielo, que en general resultaron en la supresión del crecimiento radial de los pinos y el aumento en el crecimiento radial de los robles. Además, los pulsos de establecimiento sotobosque coincidieron con grandes tormentas de hielo. La falta de perturbación del sotobosque como el fuego puede estar permitiendo el establecimiento de especies tolerantes a la sombra de sotobosque mientras limitar el establecimiento de pino y roble. La perturbación del dosel por causa de las tormentas de hielo puede estar acelerando el ritmo de este cambio composicional. Bajo el régimen de perturbación actual, la composición de la reserva es probable que cambie, lo que lleva a un aumento de arce rojo y nuez dura de mockernut y una disminución de las especies de pino y roble.

Recovery from topkill of shortleaf pine × loblolly pine hybrids compared to their parent populations

Hybrids between shortleaf pine (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.) have increased since the 1950s throughout the southeastern USA. Previously, greater sprouting capacity and the formation of a basal crook that lowers the height of dormant buds may have favored pure shortleaf pine populations on fire prone sites. The objective of this study was to determine how seasonal timing of topkill by both fire and topclipping affect sprouting of shortleaf × loblolly pine F1 hybrids compared to their parent open-pollinated populations during their third growing season. A factorial combination of top-clipping (hand pruners) and girdling by fire (propane torch) was conducted on November 2010, January, March, and April 2011 and sprouting response was measured after the growing season. Survival of topkilled shortleaf pine (94 %) was greatest followed by hybrid (78 %) and loblolly pine (35 %). However, species effects varied with topkill treatment and treatment date because survival was relatively lower for loblolly and hybrid pines in the burn-only as well as the November and April treatment dates while survival of shortleaf pine was consistently high. The number of sprouts was greatest for shortleaf (32.3) intermediate for hybrid (23.8) and lowest for loblolly pine (12.0). Overall, 83 % of shortleaf pine, 35 % of hybrid pine, and 5 % of loblolly pine exhibited a basal crook. The height from ground line to the lowest sprout was shortest for shortleaf (3.5 mm), intermediate for hybrids (7.7 mm), and largest for loblolly pine (21.3 mm). While the hybrid saplings exhibited intermediate performance in survival, sprouting capacity, and crooking, pure shortleaf pine were superior and are probably better suited to recover from fire.

Predicting litter and live herb fuel consumption during prescribed fires in native and old-field upland pine communities of the southeastern United States

The ability to predict fuel consumption during fires is essential for a wide range of applications, including estimation of fire effects and fire emissions. This project identified predictors of fuel consumption for the dominant fuel bed components (litter (<0.6-cm diameter dead material) and live herbs) during 217 prescribed fires in native longleaf pine ( Pinus palustris Mill.) and old-field loblolly pine ( Pinus taeda L.) – shortleaf pine ( Pinus echinata Mill.) communities in the southeastern United States. Additionally, these data were used to validate the First Order Fire Effects Model (FOFEM) fuel consumption computer model using custom and default fuel loads. Regression models using empirical data suggested that litter and live herb fuel consumption can be predicted by prefire litter and live herb fuel loads, litter and live herb fuel moisture, litter fuel bed bulk density, season of burn, years since fire, days since last rain ≥0.64 cm, relative humidity, energy release component, community type, pine and hardwood basal areas, and the Keetch–Byram drought index. FOFEM’s prediction of fuel consumption for litter, live herbs, and duff combined using default fuel loads was 1.5 times the measured fuel consumption (where duff fuel load was zero). Refinement of FOFEM’s fuel load and consumption calculations in the studied community types using the newly collected data and suggestions for model improvement would provide more accurate air quality inventories and assist in guiding appropriate regulation of prescribed fire.

Physiological and morphological attributes of shortleaf × loblolly pine F1 hybrid seedlings: is there an advantage to being a hybrid?

Fire suppression and other anthropogenic activities have the potential to eliminate ecological barriers that previously kept related, sympatric species from interbreeding. We compared artificial F1 shortleaf pine (Pinus echinata Mill.) × loblolly pine (Pinus taeda L.) hybrids with their parents to determine potential traits that have allowed hybrid seedlings to dramatically increase in abundance since 1950s. Six open-pollinated families each of loblolly and shortleaf pine as well as 12 controlled crosses were compared over 2 years in Oklahoma, USA. Loblolly and hybrid seedlings had higher establishment and growth rates than shortleaf pine. The hybrid seedlings had similar numbers of sprouts following top-clipping as shortleaf, which were higher than those of loblolly pine. Formation of a strong basal crook, an adaptation to protect dormant buds from fire, was greatest in shortleaf and lower in hybrid and loblolly pine. Instantaneous water use efficiency indicated that hybrid pine had similar high water us...

Comparison of Tissue Heat Balance- and Thermal Dissipation-Derived Sap Flow Measurements in Ring-Porous Oaks and a Pine

Sap flow measurements have become integral in many physiological and ecological investigations. A number of methods are used to estimate sap flow rates in trees, but probably the most popular is the thermal dissipation (TD) method because of its affordability, relatively low power consumption, and ease of use. However, there have been questions about the use of this method in ring-porous species and whether individual species and site calibrations are needed. We made concurrent measurements of sap flow rates using TD sensors and the tissue heat balance (THB) method in two oak species (Quercus prinus Willd. and Quercus velutina Lam.) and one pine (Pinus echinata Mill.). We also made concurrent measurements of sap flow rates using both 1 and 2-cm long TD sensors in both oak species. We found that both the TD and THB systems tended to match well in the pine individual, but sap flow rates were underestimated by 2-cm long TD sensors in five individuals of the two ring-porous oak species. Underestimations of 20–35% occurred in Q. prinus even when a “Clearwater” correction was applied to account for the shallowness of the sapwood depth relative to the sensor length and flow rates were underestimated by up to 50% in Q. velutina. Two centimeter long TD sensors also underestimated flow rates compared with 1-cm long sensors in Q. prinus, but only at large flow rates. When 2-cm long sensor data in Q. prinus were scaled using the regression with 1-cm long data, daily flow rates matched well with the rates measured by the THB system. Daily plot level transpiration estimated using TD sap flow rates and scaled 1 cm sensor data averaged about 15% lower than those estimated by the THB method. Therefore, these results suggest that 1-cm long sensors are appropriate in species with shallow sapwood, however more corrections may be necessary in ring-porous species.

Revivification of a method for identifying longleaf pine timber and its application to southern pine relicts in southeastern Virginia

Longleaf pine ( Pinus palustris Mill.) cannot be distinguished from the other southern pines based on wood anatomy alone. A method that involves measuring pith and second annual ring diameters, reported by Arthur Koehler in 1932 (The Southern Lumberman, 145: 36–37), was revisited as an option for identifying longleaf pine timbers and stumps. Cross-section disks of longleaf, loblolly ( Pinus taeda L.), and shortleaf ( Pinus echinata Mill.) pines were measured and the diameters of their piths and second annual rings plotted against each other. From this plot, longleaf pine could be differentiated from the other two southern pine species, demonstrating that a method established with trees harvested more than 70 years ago is still applicable to standing timber of today. No evidence was found to suggest that different growth rates impact method applicability. In those situations where the second annual ring is intact, but not the pith, very large second annual ring diameters (>40 mm) may identify timbers with a lower probability of being longleaf pine. In addition to the identification of very old lightwood stumps as part of a longleaf pine restoration effort, both methods may be applied to timber identification in historic structures and the niche forest products industry involving the recovery and processing of highly prized longleaf pine logs from river bottoms. Measurements from relicts sampled in this study were consistent with the purported range for longleaf pine in Virginia.

An individual-tree diameter growth model for managed uneven-aged oak-shortleaf pine stands in the Ozark Highlands of Missouri, USA

The Pioneer Forest encompasses more than 60,000ha in the Ozark Highlands of Missouri, USA and has been managed using single-tree selection since the early 1950s. This paper quantifies the influence of tree size and competitive position, stand density, species composition, and site quality on ten-year (1992–2002) diameter increment within oak (Quercus spp.) and shortleaf pine (Pinus echinata Mill.) stands on the Pioneer Forest. An individual-tree model was developed for each species using mixed-effects regression and 290 inventory plots. Model efficiency (R2) ranged from 0.26 to 0.57 and fit was generally better for oak species. Basal area in larger trees (BAL) and tree diameter were significant predictors for all species and crown competition factor improved prediction for shortleaf pine and hickory (Carya spp.). Effect of species composition and site quality on diameter growth was not consistent across species. Models were evaluated using a subset of data not included in model fitting and the effect of single tree and standwise (1, 3, or 5 sample trees) calibration on model predictions were evaluated. Inclusion of random effects through calibration improved model prediction for all species and fit was best following single tree and 3 tree calibration.

Effect of Thinning on Aboveground Biomass Accumulation and Distribution in Naturally Regenerated Shortleaf Pine

Abstract The accumulation and relative distribution of standing biomass to different aboveground tree components was investigated in 46–53-year-old naturally regenerated shortleaf pine (Pinus echinata Mill.) stands growing in the Ouachita Mountains of southeastern Oklahoma that were thinned to different levels 16 years previously. The thinning levels were 50% full stocking, 70% full stocking, and a 140% full stocking unthinned control. After 16 years, the unthinned controls had more total aboveground biomass, bole wood, bark, and foliage standing biomass per hectare but had less branch standing biomass than the more heavily thinned stands. Foliage biomass as a proportion of total stand biomass was similar among the three treatment levels. Bark biomass proportion was significantly less in thinned to 50% treatment compared with the other treatments. Bole wood biomass proportion in thinned to 50% treatment was significantly less than in the control. The proportion in branches was significantly greater in the thinned treatments compared with the proportion in the unthinned control. These results suggest that thinning increases biomass distribution to branches at the expense of stems, after 16 years of postthinning stand growth.

Desempenho do <i>Pinus echinata</i> na Região Central do estado do Rio Grande do Sul, Brasil.

Neste trabalho, estudou-se o crescimento e a produção em povoamento de Pinus echinata Mill. O povoamento foi instalado em 1996 em espaçamento de 3,0 x 2,0 metros, no município de Boqueirão do Leão, no estado do Rio Grande do Sul, Brasil. Para o estudo, foram instaladas seis unidades amostrais, onde foram medidas e abatidas seis árvores de diâmetro médio e de altura dominante para análise de tronco. Os resultados obtidos indicam que a espécie apresenta bom potencial de crescimento em diâmetro, altura e volume. Aos 12 anos de idade, o povoamento apresentou um diâmetro médio de 18,4 cm, altura média de 12,6 m, altura dominante de 14,1 m, área basal de 42,3 m2.ha-1, volume total com casca de 248,2 m3.ha-1 e um incremento médio anual de 20,7 m3.ha-1.ano-1. Tais resultados iniciais indicam que a espécie apresenta potencial de crescimento e produção, podendo ser indicada para cultivo no estado do Rio Grande do Sul.

Tree Biomass Equations for Naturally Regenerated Shortleaf Pine

Abstract Aboveground tree-level and branch-level biomass component equations were fitted by nonlinear seemingly unrelated regression, for even-aged naturally regenerated shortleaf pine (Pinus echinata Mill.) in southeastern Oklahoma. Data were obtained from 46- to 53-year-old trees growing in stands that had previously been thinned to densities ranging from 50% of full stocking to overstocked unthinned stands. Stand density affected some of the parameter estimates for trees growing in thinned stands versus unthinned stands. Equations based on dbh alone gave biomass estimates that were not significantly different from those obtained with equations based on dbh, height, and/or crown width. The fitted tree-level biomass component equations were additive in the sense that predictions for biomass components were constrained by the estimation process to sum to total tree biomass. These equations can be used to estimate aboveground tree or tree component biomass for naturally regenerated shortleaf pine in the dbh range of 7–40 cm in southeastern Oklahoma and have potential for application in other shortleaf pine growing areas.