The objective of this study was to develop diameter/basal area increment equations for loblolly pine trees in thinned and unthinned plantations on cutover, site-prepared areas. Results indicated that one set of coefficients was sufficient to estimate individual tree growth (for the three year period following thinning) on lightly thinned and heavily thinned plots. However, unthinned plots required a separate set of coefficients and therefore a separate equation to estimate growth. Diameter growth was adequately explained by some form of the following regressor variables: pine basal area, hardwood basal area, initial age, initial diameter, average height of the dominant and codominant trees, and crown ratio ( optional). Transforming the dependent variable from a function of diameter to a similar function of basal area had no apparent effect on the precision of the predicted results. Two alternative methods of predicting diameter growth were evaluated: (1) direct fitting of diameter growth, and (2) fitting a potential diameter growth equation and a modifier function. Even though the potential times modifier approach performed slightly better in terms of fitting the data, it provided unrealistic results at ages beyond the upper range of the data. After additional data are obtained at older ages, the potential times modifier approach may surpass the direct approach. However, at present, the direct diameter growth model was chosen as the final model form. / M.S.

A loblolly pine phosphorus fertilization trial was evaluated 20 years after establishment on a Tatum silt loam in the Virginia Piedmont. Triple superphosphate (TSP) was applied at 160 kg P/ha and ground rock phosphate (GRP) was applied at both 160 kg P/ha and 670 kg P/ha. Lime (4.48 T/ha) was applied with and without the TSP treatment. Tree growth was not significantly affected by treatment and foliar phosphorus levels were above 0.10% indicating that a deficiency was not the immediate growth limiting factor. Double-acid-extractable soil phosphorus critical levels established for the Coastal Plain do not appear useful for diagnosing tree requirements for this Piedmont soil. A critical level of 1.0 ppm double-acid-extractable phosphorus would be more applicable to this soil. GRP was more effective than TSP after 20 years at increasing phosphorus uptake, probably due to a slower dissolution rate and the inclusion of F-ions which reacted with soil Al to reduce phosphorus fixation. Although an increase in the A horizon pH persisted for 20 years, there was no increase in phosphorus uptake as a direct response to this higher pH. Liming may have some long-term merit when applied in conjunction with a water soluble phosphorus fertilizer such as TSP by reducing the transformations of applied phosphorus to unavailable forms. / Master of Science

The longitudinal air permeabilities of the wood of 1116 specimens from 279 trees, two sapwood and two heartwood replicates, representing two varieties of lodgepole pine (Pinus contorta, vars. latifolia and murrayana) were measured with a steady state apparatus. It was found that the mean ratio of sapwood to heartwood permeability was ca. 10:1 for both varieties. The mean ratio of var. latifolia to murrayana was 1.5:5 and 1.75:5 for sapwood and heartwood, respectively. The most important source of variation following the difference between heartwood and sapwood was that among trees. Geographical locations, such as latitude and elevation did not significantly influence permeability. Tree size did, but only because the small trees (3 inch diameter) showed higher heartwood permeability and lower sapwood permeability than normal. Ca. 20 specimens of latifolia heartwood showed extremely high permeabilities. They were also deeply brown in color, which probably was caused by fungal or bacterial infestation. Pit pore size and number per cm² were determined for sapwood by making four permeability measurements, each at a different average pressure on each specimen. A mean pit pore radius of 1.5 µm and 1.3 µm for sapwood of var. latifolia and var. murrayana was calculated. The median values between 1200-1300 pit pores per cm² indicate an average rate of tracheid connection of 1.2-1.3%. Of the tested wood parameters including moisture content and specific gravity average ringwidth, only the permeability of var. latifolia was significantly correlated with moisture content for both heartwood and sapwood, with a negative correlation coefficient. Water retention measurements were carried out to relate the measured gas permeability of an individual specimen to its ability to absorb water. For both varieties the retention was significantly and quadratically correlated with sapwood permeability (R² = 0.286 and 0.224) and was linearly correlated with heartwood permeability (R² = 0.488 and 0.5775). The correlation factors for the regression between retention and the logarithm of permeability were 0.239 and 0.227 for sapwood and 0.447 and 0.420 for heartwood. / M.S.

Thirteen white pine plots, ranging from 15-26 years of age and one tenth acre in size, were sampled in six counties of southwestern Virginia. The number of trees attacked by the white-pine weevil ranged from 3.5 percent to 98.6 percent with an average of 40.0 percent. The incidence of forking was found to be 4.1 percent of the trees weevi1ed. Enough trees in the dominant and co-dominant crOvffi categories were either free of weevil attacks or only attacked once that 250 to 300 trees are available for final harvest. Most of the weevil attacks occurred between 5 to 12 years of age. Analysis of Covariance for non-weevi1ed terminals and lateral lengths developed the following relationship for three age classes of terminals and laterals. / Master of Science

Field and greenhouse studies were conducted to investigate the role of water stress and time of glyphosate spraying in the variation in glyphosate efficacy. Data on water potential, foliar sugar and starch content, weather, and growth response were gathered for loblolly pine and four of its major competitors on 16 operationally sprayed tracts in Virginia. Glyphosate successfully released loblolly pine on all tracts. Control of white oaks was significantly related to foliar sugar concentration. Water potential and weather variables were not related to glyphosate efficacy for any species. Seedlings of loblolly pine, red maple, and sweetgum were raised in a greenhouse and nursery environment. At the end of the second growing season, three water stress treatments were imposed on each species at each of four glyphosate application dates. ¹⁴C-glyphosate was applied to a subsample of seedlings. Timing of application. water stress, or both significantly affected susceptibility of all three species to glyphosate. Efficacy for all three species corresponded to that expected from field data. Differences in species susceptibility to glyphosate were explained by differences in ¹⁴C-glyphosate translocation, but there was no difference among species in absorption of glyphosate. Efficacy changes across application dates followed seasonal changes in foliar sugar concentration. / Master of Science

An vitro protein synthesizing system using Sephadex G-25 gel filtration for supernatant purification was used to determine the ability of extracts from embryos of dormant and stratified sugar pine seeds to promote protein synthesis. It was found that the ribosomes from the embryos of dormant seeds were more active than those from stratified seeds but they also required a greater quantity of supernatant protein to produce this activity. The supernatant fraction from stratified embryos was more active than that from dormant embryos but there were indications that this increase was due to seed imbibition. Concentrations of other essential components of the system were the same for both dormant and stratified embryo systems. In each 0.5 m1 sample, maximum incorporation occurred using 0.03-0.06 mg ribosomal protein, 0.795 μmo1es ATP, 1.8 μmo1es PEP, 13.2 μgms pyruvate kinase, 0.090 μmoles GTP, and 0.0375 mg polyuridylic acid. Optimum incubation conditions were at 37°C for 60 minutes. Ribonuclease and protease inhibited phenylalanine incorporation. Ribonuclease activity in the supernatant fraction increased with purification and was significantly higher in the dormant embryos than in the stratified. Protease activity decreased with purification of the supernatant and there was no significant difference between activity in the dormant and stratified embryo supernatant fractions. Protease activity was high in the ribosomal fraction. Ribosomes from dormant embryos appeared to bind more polyuridylic acid than did those from stratified embryos. Resedimented ribosomes consisted primarily of monoribosomes but some polyribosomes were present in both dormant and stratified embryos. Analysis of incubation mixtures produced similar results. The majority of the labelled polyphenylalanine was associated with the monoribosomes. / Master of Science

The disposal of pulp and paper industry sludge has become a significant problem in recent years. Increasing costs and regulatory constraints associated with landfilling and incineration have caused the industry to look for viable alternatives for the disposal of their wastes. In September of 1988, a nutrient-enriched, combined (primary/secondary) paper mill sludge was surface applied to a 4-year-old and a 6-year-old red pine (Pinus resinosa Ait.) plantation in central Wisconsin at rates of 10, 20 and 40 dry Mg ha⁻¹. Red pines measured 10 and 22 months following sludge application did not show a significant volume growth response to increasing sludge rates. Nonetheless, some biologically significant trends did occur following the first growing season, namely, diameter growth in the younger plantation decreased by 27%, 36% and 39% with increasing rates of sludge application. Reductions in height, crown width and volume growth were seen as well. Increased absorption of moisture among the heavier application rates coupled with already dry conditions is believed to be the cause of the growth reduction. Tree growth in the older plantation was more variable, possibly reflecting the greater degree of establishment and reduced susceptibility to moisture deficits. By the end of the second growing season, there was some indication that the trees were responding to sludge application in both plantations, with the greatest growth occurring among the 40 Mg ha TM treatment plots for all growth parameters. Red pine fascicles examined 12 months following sludge application showed significant increases in foliar concentrations of N, P, Ca, Mg and S with increasing rate of sludge application. This corresponded with a significant increase in fascicle biomass relative to application rate in the younger plantation. Fascicle biomass was not affected by sludge application in the older plantation. Analysis of nutrient response, in general, indicated luxury consumption taking place among all nutrients with the exception of boron, which decreased in foliar concentration, to low or deficient levels, and content in sludge amended plots in both plantations. Analysis for nutrient concentrations and dry matter production of Carex spp. (sedge), the predominant herbaceous understory component, showed increasing foliar N levels with sludge application 21 months following treatment in above-ground tissue, with a corresponding increase in above-ground biomass relative to controls of 22%, 33% and 85% among the 10, 20 and 40 Mg/ha treatments, respectively. An assessment of woody vegetation using a competing vegetation assessment system (CVAS) showed essentially no response by hardwood competition to sludge application for either study site. Total weed control, consisting of 0.140 kg ha⁻¹ a.i. of Oust™ and 1.3 kg ha⁻¹ a.i. of Garlon™ was performed in August of 1989 and resulted in significantly reduced coverage of herbaceous and woody competing vegetation in both plantations the following growing season. Analysis of red pine volume growth between weed control treatments did not show a significant response relative to sludge application for either plantation one year following herbicide application. Additionally, there was evidence of reduced weed control efficacy with increasing sludge application rate in the younger plantation. This suggests that weed control efficacy may be greater if weed control is performed prior to sludge application; however, given the apparent sequestering ability of the herbaceous vegetation, removal of this component may contribute to elevated levels of undesirable leachates in soilwater and groundwater. / Master of Science

Crown structure for 9- to 30-year-old loblolly pine was quantified via analysis of branch diameters and location, both along and around the bole, using observational data from 68 trees. The trees analyzed ranged in size from 11.1 to 31.6 cm in DBH and from 8.30 to 25.67 m in height, and were growing in Piedmont and Atlantic Coastal Plain stands ranging from 70 to 200 sq. ft. BA/acre. A series of equations was used to describe the diameter distribution of branches. Circular statistics were used to examine branching patterns around the bole. A recursive system of 2 equations was developed in order to predict the total number of branches within a crown. A series of 3 equations was used to describe the average of and range in diameter within a whorl. Attempts at modeling the height above ground to branches (whorls) were unsuccessful; therefore, equidistant spacing was assumed. Similarly, predicting the number of branches within a whorl of a certain height was difficult, and overall percentages were employed. Analysis of branch azimuths on a whole tree basis indicated a uniform distribution was appropriate (and not a “circular normal” distribution). Finally circular correlation was used to analyze rotational patterns within and between whorls, and a strong positive correlation was found for consecutive whorls of the same number of branches. From this study it was concluded that modeling crown structure will be difficult, with much variation occurring among trees. More data are necessary to better refine the baseline work herein presented. / Master of Science

Experiments were conducted on the use of granular fenuron, 25% active, for white pine release and establishment. The effect of fenuron on the plant community was also investigated. Studies included in the white pine release experiment were the effect of season of treatment on the kill of hardwoods and percentage survival of indigenous white pine, and the effectiveness of fenuron on various species of hardwoods. All hardwood stems over six feet tall were treated with four grams of active fenuron placed on the soil at the base of the tree. Treatments were made in May 1960, August 1960, and March 1961. The May treatment was most effective in the removal of the hardwoods. There was a reduction of 59% of pines over six feet tall and an increase of 45% of pines less than six feet tall. Red maple and the oaks were the species most susceptible to the treatment; whereas, chestnut, sassafras, and black locust were the least susceptible. In the white pine establishment experiment, the residual effect of fenuron on white pine seedlings, and its effectiveness at a lower rate on various hardwoods were lnvestigated. Each hardwood stem over six feet tall was treated with one gram active fenuron in the spring of 1960. In March 1961, 100 white pine seedlings were planted in each of three plots previously treated. Five months after planting there was 99% survival of the pine seedlings. The one-gram rate was effective against red maple and the oaks but had little effect on sassafras, cucumber tree, and chestnut. Fenuron in some manner changed the composition of the plant community. Fireweed, poke, and several species of Panicum were present in the treated plots but were not present in the untreated buffer strips. / Master of Science

Thinning from above and below were compared using an economic optimizing dynamic program, FORTE (Arthaud 1986). Economically optimal (net present value maximizing) thinning regime and rotation age were determined for benchmark economic and model inputs. Sensitivity of net present value and optimal management regime were tested for varying interest rates (6 or 8%), site indexes (50, 60 and 70, base 25 years), fixed and variable thinning costs, planting density (440, 680 and 910 trees per acre), stumpage prices and thinning type. Given the same assumptions, thinning from below consistently provided the higher net present value for the optimal regime than thinning from above. For the benchmark assumptions, both thinning types had two thinnings in their optimal regimes. Optimal rotation age and thinning timings occur later when thinning from above. Both thinning types provided higher net present values than not thinning under all conditions except pulpwood management. / Master of Science