Slash Pine Plantations Research Articles

Phenology and productivity of saw palmetto (<i>Serenoa repens</i>) in a north Florida slash pine plantation

Phenology and productivity of saw palmetto (<i>Serenoa repens</i>) in a north Florida slash pine plantation

Remarks on the 'Bayesian' method of moments

Zellner has proposed a novel methodology for estimating structural parameters and predicting future observables based on two moments of a subjective distribution and the application of the maximum entropy principle-all in the absence of an explicit statistical model or likelihood function for the data. He calls his procedure the 'Bayesian method of moments' (BMOM). In a recent paper in this journal, Green and Strawderman applied the BMOM to a model for slash pine plantations. It is our view that there are inconsistencies between BMOM and Bayesian (conditional) probability, as we explain in this paper.

Soil redox potential in small pondcypress swamps after harvesting

Soil environmental conditions were investigated in nine stillwater swamps dominated by pondcypress ( Taxodium distichum var. nutans) in north central Florida. Three swamps were left unharvested (control); three were harvested, but surrounding slash pine plantations were left intact (swamp harvest); and three were harvested along with the surrounding slash pine plantations (swamp+upland harvest). Measurements of soil redox potential ( E h) and other soil and water properties were collected for 5 months before harvesting (December 1993–April 1994) and for 2 years after harvesting (May 1994–May 1996). No significant differences in water level resulted from harvesting, although control swamps became dry and harvested swamps remained flooded shortly after harvesting. E h in the swamp+upland harvest treatment was lower than in the control treatment for only 1 month (July 1994) after logging but was also lower in areas where the soil was compacted by skidder equipment. Short-term increase in water level and soil compaction by skidder trafficking appear to have minimal long-term effects on soil environmental conditions.

Influence of Planting Density on Diameter and Height in East Texas Pine Plantations

Abstract The response of diameter and height of unthinned planted stands loblolly (Pinus taeda L.) and slash (Pinus elliottii Engelm.) pine in East Texas to different classes of planting densities were analyzed. After tracking the development of diameter and height for 15 yr on a set of permanent plots representing a broad range of plantation parameters, average diameter and average height trends were observed. For both species, average diameter values were significantly larger with lower planting densities. In contrast, average height growth is insensitive to planting density at younger age classes for loblolly and at older age classes for slash pine plantations. South. J. Appl. For. 22(4):241-244.

Use of Forested Habitat by Breeding Birds in the Gulf Coastal Plain

Abstract I compared birds present during the breeding season in four forest types in the Conecuh National Forest located on the Gulf Coastal Plain in Alabama: (1) longleaf pine (Pinus palustris) that had been subject to several recent burns, (2) longleaf pine that had been subject to few or no recent burns, (3) planted slash pine (P. elliottii), and (4) various forested wetland habitats ranging from stream-side riparian habitat to cypress (Taxodium distichum) ponds. I found significantly higher total individuals and significantly higher bird species richness in the two natural forest types—burned longleaf pine and riparian habitats—than either unburned longleaf or slash pine. To maintain greatest diversity and abundance of birds, managers of forests on the Gulf Coastal Plain should (1)preserve wetland habitat, (2) not convert stands of longleaf pine to stands of slash pine, and (3) regularly burn longleaf pine stands. South. J. Appl. For. 22(3):133-137.

Survival of Slash Pine Having Fusiform Rust Disease Varies with Year of First Stem Infection and Severity

Abstract Probabilities of death of young slash pine infected by fusiform rust pathogen varied with timing and severity of infection. Trees in nine slash pine plantations varying widely in site quality and initial number of trees per acre had similar probabilities of death from rust. About 90% of trees with stem infections in the first three growing seasons died by age 15 if the gall spanned more than 50% of the circumference of the stem by age 5. If 50% gall encirclement occurred after age 5, mortality rates dropped to about 30% at age 15. Where first stem infection occurred after the fifth year, probability of death was essentially the same as for rust-free trees. Methods are given for using timing-severity data to estimate future stocking. South. J. Appl. For. 22(2):96-100.

Soil CO2 efflux and its spatial variation in a Florida slash pine plantation.

The efflux of CO2 from the soil surface can vary markedly in magnitude both in time and space and its correct determination is crucial in many ecological studies. In this paper, we report results of field measurements, using an open-top dynamic chamber, of soil CO2 efflux in a mature Florida slash pine (Pinus elliottii Engelm. var.elliottii) plantation. The daily average efflux was 0.217 mg CO2 m-2s-1 in the autumn and 0.087 mg CO2 m-2s-1 in the winter. Soil temperature, which accounts for most of the temporal variability in CO2 efflux, is by far the most influential factor controlling soil respiration rate and its temporal variation. The CO2 efflux in the slash pine plantation is highly spatially variable and effluxes from the soil under palmetto is significantly higher than that from the open floor. The CO2 efflux generally increases with increase in soil fine root biomass, litter and humus amount on the forest floor but is inversely related to the amount of organic matter in the mineral soil. The spatial variation in CO2 efflux can be well characterised by a simple multiple regression model incorporating live and dead biomass and soil total porosity as predictor variables. Understorey plants, mostly Serenoa repens, are an important component of the C cycle and the major contributor to the spatial heterogeneity of soil CO2 efflux. The influence of understorey plants on soil respiration is probably via two approaches: increasing litterfall and root metabolism, both consequently stimulating microbial activity in the mineral soil.

Leaf litterfall, leaf area index, and radiation transmittance in cypress wetlands and slash pine plantations in north-central Florida

The seasonal dynamics of leaf litterfall and leaf area index (LAI, all-sided basis), light penetration and the vertical distribution of surface area index, and the feasibility of estimating LAI from radiation transmittance were studied from April 1993 to March 1994 in the canopies of three cypress (Taxodium ascendens) wetlands and their surrounding slash pine (Pinus elliottii) uplands in Florida flatwoods. Annual leaf litterfall ranged from 324 to 359 g m−2 in the wetlands, which was very close to the average for 11 sites throughout Florida of 340±26 g m−2. The seasonal pattern of the normalized LAI obtained for the dominant tree species in the ecosystems could be used to construct the seasonal dynamics of LAI at the ecosystem scale. The vertical distribution of surface area index in the wetlands was significantly different from that in the surrounding pine uplands. The maximum LAI of cypress wetlands in this area was about 8 m2 m−2, which was higher than the maximum of slash pine plantations of 6 m2 m−2. Cypress leaves were strongly erectophile in space. Results showed that the LAI-2000 canopy analyzer could generally be used to estimate forest LAI, whether the forest canopy was closed or not, if an overall clumping index of 2.00 was applied. However, as LAI decreased, the relative error contained in the radiation-based LAI estimates increased. This indicated that foliage clumping at the stand scale was more important than that at the tree or branch scale.

Site Preparation and Fertilization Effects on Growth of Slash Pine for Two Rotations

AbstractTwo replicated site preparation studies were used to examine the effect of management on pine height and volume growth in the next rotation on Paleudults. Treatments included no tillage, flat disking, bedding, and fertilization. The first rotation of planted slash pine (Pinus elliottii Engelm. var. elliottii) was measured for 15 yr on one site and 20 yr at the other, harvested, and replanted without additional tillage. The second rotations were measured for 10 yr. At one site, 100 kg ha−1 P was applied to each rotation as a treatment variable. At one site, disking before the first rotation increased pine heights. Bedding before the first rotation increased pine heights at both sites. In the second rotation, the response was reversed, with pines planted on beds being the shortest. The P fertilization increased heights in both rotations but did not affect response to tillage. The P as well as N, applied only at age 7 in the second rotation, had a negative effect on the second rotation's volume, probably because of increased competition from shrubs and other understory plants. Across both sites and for all treatments, 10‐yr‐old slash pines averaged 7% less in height and 24% less in volume in the second rotation. These differences are statistically significant. Analysis at age 10 from both rotations indicates stable foliar concentrations of P and Ca, declining K, and increasing Mn and Al.

A Bayesian growth and yield model for slash pine plantations

We formulate a traditional growth and yield model as a Bayes model. We attempt to introduce as few new assumptions as possible. Zellner's Bayesian method of moments procedure is used, because the published model did not include any distributional assumptions. We generate predictive posterior samples for a number of stand variables using the Gibbs sampler. The means of the samples compare favorably with the predictions from the published model. In addition, our model delivers distributions of outcomes, from which it is easy to establish measures of uncertainty, such as highest posterior density regions.

Effects of Slash Pine Silviculture on a Florida Population of Flatwoods Salamander

The largest known breeding migration of the flatwoods salamander (Ambystoma cingulatum) was monitored over a 22‐year period following its discovery in 1970 in Liberty County, Florida (U.S.A.). Nightly migrations of 200–300 adults across a 4.3‐km stretch of paved highway in 1970–1972 had dwindled to less than one individual per night in 1990–1992; the decline apparently was already underway in the 1980s. We discuss possible natural and anthropogenic causes of the decline. The silvicultural practice of converting native longleaf pine savanna to bedded slash pine plantation, implemented on our study site about 1968, may have interfered with migration, successful hatching, larval life, feeding, and finding suitable cover post‐metamorphosis. Longleaf pine‐wiregrass flatwoods inhabited by adults have been drastically reduced and severely degraded throughout the coastal plain and may explain why the species is rare and deserving of threatened status.

Total and Partial Stand-Level Yield Prediction for Loblolly and Slash Pine Plantations in East Texas

Abstract Observations from East Texas Pine Plantation Research Project permanent plots in loblolly (Pinus taeda L.) and slash (Pinus elliottii Engelm.) pine plantations throughout East Texas were utilized to develop methods to estimate stand-level yield values. Predicted yields are volume in cubic feet and green weight in pounds. Predictor variables for total yield are plantation age, site index (base age 25 yr) and surviving trees per acre. Partial yield is derived using total yield and plantation quadratic mean diameter in conjunction with specified threshold dbh and upper stem dob values. Expected total yield per acre is converted to partial yield per acre by considering combinations of threshold dbh and upper stem dob values. For each combination, total yield per acre is reduced by a proportional value to estimate a partial yield per acre. South. J. Appl. For. 20(1):36-41.

Predicting Survival of East Texas Loblolly and Slash Pine Plantations Infected with Fusiform Rust

Abstract Repeated measurements during 1982-1992 of East Texas Pine Plantation Research Project permanent plots in loblolly (Pinus taeda L.) and slash (Pinus elliottii Engelm.) pine plantations throughout East Texas were used to develop equations for predicting the future number of trees per acre. A typical condition of East Texas pine plantations is the incidence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme). A regression procedure for fitting nonlinear systems of equations was used to fit survival models that considered the possibility that trees with no rust galls on the stem could either (1) remain uninfected and alive, (2) become infected yet still alive or (3) die. For infected stems, only two possible outcomes were considered in the model: (1) remain infected and alive or (2) die. Analyses of the differences between predicted and observed values indicated no adverse trends for either of the two species. Apparently the models do represent observed survival patterns. South. J. Appl. For. 20(1):30-35.

Structural Estimation of the Stochastic Dynamic Decision Problems of Resource Users: An Application to the Timber Harvest Decision

This paper examines a method for structural estimation of the stochastic dynamic decision problems of resource users. The method involves nesting a stochastic dynamic programming algorithm within a maximum likelihood routine. An application to the timber harvest decision indicates that owners of slash pine plantations in southeast Georgia use a low discount rate and treat timber price as a random walk. Moreover, the harvest decision is apparently dominated by profit shocks overlooked in the usual models of the harvest decision.

Modeling Stand Level Growth and Yield Response to Silvicultural Treatments

Abstract As plantation growth and yield research lead to new, more intensive, and site-specific silvicultural prescriptions, there is a perpetual need to adjust existing yield prediction models to reflect the response to these practices. A height growth model that includes a treatment response term to accommodate different expected response patterns is presented. This model is shown to provide an accurate description of the observed average dominant height growth response of slash pine plantations to several silvicultural treatments, relative to standard practice. An existing per-acre basal area prediction model for unthinned plantations that includes average dominant height as a predictor variable, in addition to age and trees per acre, also required an adjustment term to adequately reflect treatment effects on stand basal area growth. No such adjustment appeared to be necessary, to account for different silvicultural practices, to an existing stand level volume prediction model that includes both average dominant height and basal area per acre as predictor variables, in addition to age and trees per acre. For. Sci. 41(3):629-638.

Combinations of Fungicide and Cultural Practices Influence the Incidence and Impact of Fusiform Rust in Slash Pine Plantations

Abstract Slash pine was grown in central Louisiana under four levels of culture with or without repeated sprayings of the systemic fungicide triadimefon for protection against fusiform rust. The eight treatment combinations were: (1) no fungicide, weed control or fertilizer; (2) weeded; (3) weeded, applied inorganic fertilizer, and bedded before planting; (4) weeded, bedded, and applied inorganic fertilizer in the sixth growing season (delayed fertilization); (5) applied fungicide but no weed control or fertilizer; (6) applied fungicide and weeded; (7) applied fungicide plus treatment 3; and (8) applied fungicide plus treatment 4. Fungicide applications greatly reduced fusiform rust impact in 10-yr-old slash pine stands. Fungicide treatments resulted in higher survival fewer trees with stem galls, fewer trees with galls encircling 76%-100% of the stem circumference, greater total volume/ac, and less volume/ac among infected trees. The fungicide-treated trees had fewer stem galls below 5 ft of tree height compared with untreated trees, indicating that the fungicide treatment protected planted seedlings through several growing seasons. Weed control increased fusiform rust incidence. The fungicide-treated plots receiving delayed fertilization yielded the most volume (3,018 ft3/ac) after 10 growing seasons because of high stocking and accelerated growth following fertilization. South. J. Appl. For. (2):53-59.

Determining Site Index and Estimating Timber Volumes Without Measuring Heights

Abstract We present a time-saving method for predicting average dominant height, and thus site index, and predicting yield of a slash pine (Pinus elliottii Engelm.) plantation without measuring any tree heights. We identify a segment in the upper end of the diameter distribution where the average height of all trees is equal to average dominant height. The arithmetic mean diameter of these trees, called dominant height diameter (DHD), is used in a regression to predict average dominant height. With individual tree height prediction equations that use average dominant height and tree volume or weight equations that use tree height and dbh, plot volumes or weights can then be predicted. For 922 plots in slash pine plantations, total-stem volume per acre was predicted with an R2 of 0.978 with this method. South. J. Appl. For. 18(1):15-18.

Effects of nitrogen fertilization on the fluxes of N2O, CH4, and CO2 from soils in a Florida slash pine plantation

We measured fluxes of N2O, CH4 and CO2 from control and urea-nitrogen fertilized soils of a mature slash pine (Pinuselliottii var. elliottii Englem.) plantation in Alachua County, Florida. The fertilization did not affect CO2 emissions, but significantly increased the emissions of N2O and lowered the uptake of atmospheric CH4. Daily average N2O emissions from the fertilized soils were 8–600 times higher (12–74 μg N2O-N•m−2•h−1) than daily average N2O emissions from control soils (0.02–4.0 μg N2O-N•m−2•h−1). Daily average CH4 uptake by the fertilized soils were 5–20 times lower (0.001–0.007 mg CH4-C•m−2•h−1) than daily average CH4 uptake by control soils (0.015–0.035 mg CH4-C•m−2•h−1). We also measured the relative activities of the bacteria populations that were responsible for CH4 oxidation in the control and fertilized soils. Results from these measurements suggest that fertilization shifted the relative activities of the CH4 oxidizing bacteria from those dominated by methanotrophs in the control soils to those dominated by nitrifying bacteria in the surface (0–2 cm) of the fertilized soils. The shift in relative activities of these bacteria may have been responsible for the lower CH4 uptake by the fertilized soils.

Yield Prediction for Mechanically Site-Prepared Slash Pine Plantations in the Southeastern Coastal Plain

Abstract Yield prediction equations with different input requirements, and intended for stand-level management planning, are presented in four separate sections: (1) Unthinned plantations with site index and planting survival at age 2 as input. Per-acre basal area and volume prediction equations are presented. (2) Thinned or unthinned plantations with age, surviving trees per acre, and average dominant/codominant height or site index as input; (3) A Weibull distribution-based yield prediction system for existing unthinned plantations with age, surviving trees per acre, and average dominant/codominant height as input. Tree volume and height prediction equations, developed for this plantation resource, are presented. (4) Future yield for thinned and unthinned plantations when an initial stand table is available. Survival and per-acre basal area projection equations of Section 2 are required to project the stand table. South. J. Appl. For. 17(4):163-173.

Simulation of the carbon dynamics of a Florida slash pine plantation

A model of the carbon dynamics of a Florida slash pine ( Pinus elliottii) plantation was designed to use as a tool to scale up physiological data to the stand level, and to address questions about the dynamics of the labile carbon pool (starch + sugars) and fertilization responses. The model adequately simulated labile carbon dynamics, stem growth, and root respiration over a 2-year period. Measured labile carbon pool dynamics were consistent with the simulation based on a daily balance between inputs of net canopy assimilation and outputs of respiration and growth. Increased stem growth following fertilization can be simulated as a consequence of increased foliage mass; no other changes in allocation patterns or physiological responses to fertilization were evident.