Predicting Fertilizer Response in Established Loblolly Pine Plantations With Basal Area and Site Index

1982 ◽  
Vol 6 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Howard W. Duzan ◽  
H. Lee Allen ◽  
R. Ballard

Abstract In a wide range of loblolly pine (Pinus taeda L.) plantations, very few of which were suffering from severe nutrient deficiencies, response to fertilization was related to stand conditions. Gross and net volume increment equations were developed using basal area, site index, and fertilizer treatment as predictor variables. Response to fertilization was calculated as the difference between growth estimates for control and fertilized stands at given levels of basal area and site index. Predicted 5-year volume response from fertilization with 100 lbs N/A + 50 lbs P/A is given for a range of basal area and site index levels for both the Coastal Plain and Piedmont regions. The information provided will enable the forest manager to choose stands with the greatest potential for response, and to determine the economic benefits of fertilization.

2000 ◽  
Vol 24 (4) ◽  
pp. 207-212 ◽  
Author(s):  
Ralph L. Amateis ◽  
Jiping Liu ◽  
Mark J. Ducey ◽  
H. Lee Allen

Abstract Data from a fertilizer response study in loblolly pine (Pinus taeda L.) plantations at different sites in the southeastern United States were used to develop response models for dominant height and basal area following midrotation nitrogen (N) and phosphorus (P) fertilization. Nonlinear regression models developed from the data predict total cumulative response as a function of the interaction of N and P application rates, drainage class of the site, stand conditions when fertilized, and time since fertilization. Stand variables that were found to be significant predictors of response included site index, age, basal area, number of surviving trees, and dominant height at fertilization. Dominant height response was significantly greater on poorly drained sites than on other sites. Basal area response to P was significantly less on poorly drained sites and significantly greater on well drained sites. These models can be coupled with unfertilized baseline models to estimate volume response to midrotation fertilization. South. J. Appl. For. 24(4):207-212.


1988 ◽  
Vol 12 (4) ◽  
pp. 275-280 ◽  
Author(s):  
Donald H. Marx ◽  
Charles E. Cordell ◽  
Alexander Clark

Abstract Loblolly pine (Pinus taeda L) seedlings with different initial amounts of Pisolithus tinctorius (Pt) ectomycorrhizae (Pt index 0, 27, 46, 68, or 88) were planted on a good-quality site (site index 90 ft at age 50) in southwest Georgia. After 8 years and crown closure, trees with Pt indices of 88 and 68 had significantly better survival and greater heights, diameters, volumes, and green weights per tree and per ac than nursery-run, control seedlings (Pt index 0). Volume and weight yields per ac were over 50% greater and volume and weight yields per tree were over 20% greater for trees in the Pt index 88 treatment than they were for control trees. A special statistical analysis indicated that average per ac volume was positively correlated with initial Pt index values larger than 58. Tree-ring analyses showed that trees with a Pt index of 88 had significantly greater annual basal area growth than controls during growing seasons with water deficits of 8 to 13 in. Annual growth did not differ when water deficits were greater or less than these amounts. After 8 years, Pt basidiocarps were present throughout the study site. Mycorrhizal treatment integrity may have been lost after 3 or 4 years. South. J. Appl. For. 12(4):275-280


1988 ◽  
Vol 12 (4) ◽  
pp. 270-273 ◽  
Author(s):  
Charles R. Blinn ◽  
Al Lyons ◽  
Edward R. Buckner

Abstract Color aerial photography was used to assess crown color classes in loblolly pine (Pinus taeda L.) plantations. Three distinct Munsell color classes were delineated on the resulting photographs. Foliar N levels and, to a lesser degree, foliar K levels were directly related to color. Significant relationships between color and site index and color and basal area were shown. Application of color aerial photography, combined with Munsell color coding, could expedite land classification and also make possible more efficient use of fertilizers. South J. Appl. For. 12(4):270-273.


1983 ◽  
Vol 7 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Paul A. Murphy ◽  
Robert M. Farrar

Abstract Equations are given to estimate current and projected sawtimber volumes and projected basal area of the sawtimber portion of uneven-aged loblolly-shortleaf (Pinus taeda L.-Pinus echinata Mill.) pine stands managed under the selection system. The independent variables are elapsed time, initial merchantable basal area, and the initial ratio of sawtimber basal area to merchantable basal area. The results should provide guidelines for the board-foot and cubic-foot production of sawtimber-sized trees in uneven-aged stands that occur on average sites (site index 90, loblolly pine) in the Coastal Plain.


2020 ◽  
Vol 66 (5) ◽  
pp. 623-633
Author(s):  
Y H Weng ◽  
J Grogan ◽  
D W Coble

Abstract Growth response to thinning has long been a research topic of interest in forest science. This study presents the first 3–4 years of response of loblolly pine (Pinus taeda L.) growth to thinning at different intensities. Data were collected from the East Texas Pine Research Project’s region-wide loblolly pine thinning study, which covers a wide variety of stand conditions. Four treatments, light, moderate, and heavy thinning, respectively having 370, 555, and 740 residual trees per hectare after thinning, and an unthinned control, were included. Individual tree diameter at breast height (dbh) and total height were recorded annually for the first 3–4 years after thinning. Results indicate significant differences between treatments in dbh growth in each year after thinning, as well as for all years combined. Each thinning treatment had significantly greater dbh growth than the control in the first growing season with this positive response being more evident in the case of the heavier thinning or at the later years post-thinning. Conversely, the thinning effect on tree height growth was initially negligibly negative, then becoming positive after 2–4 years, with the heavier thinning becoming positive sooner. Tree size class, assigned based on prethinning dbh, had a significant effect on both dbh and height growth responses. Compared to the control, small trees had a greater response both in dbh and in height growth than the medium and large trees over the measurement period. At the stand level, the heavier thinning had significantly less stand basal area per hectare, but the difference in stand basal area per hectare between the thinned and the unthinned plots decreased with years post-thinning. Results from this study can improve our understanding in thinning effects and help forest managers make accurate decisions on silvicultural regimes.


1994 ◽  
Vol 18 (3) ◽  
pp. 128-132 ◽  
Author(s):  
Paul A. Murphy ◽  
Michael G. Shelton

Abstract The effects of three levels of residual basal area (40, 60, and 80 ft2/ac), maximum dbh (12, 16, and 20 in.) and site index (< 81 ft, 81 to 90 ft, and >90 ft) on the growth of loblolly pine (Pinus taeda L.) stands after 5 yr of uneven-aged silviculture were determined from plots located in south Arkansas and north Louisiana. Designated levels of basal area and maximum dbh were achieved by harvesting; a q factor of 1.2 (using 1 in. dbh classes) was imposed on all plots as closely as possible. Stand-level models were developed for annual per acre net volume growth (merchantable cubic feet, sawtimber cubic feet, and sawtimber board feet, Doyle rule) and annual per acre survivor growth, ingrowth, and mortality components of basal area growth. Growth for all volume measures increased with an increase in basal area. Site index did not significantly affect merchantable cubic-foot growth but had a positive effect on sawtimber growth in both cubic feet and board feet, Doyle. Increases in maximum dbh decreased merchantable and sawtimber cubic-foot growth but increased growth for board-foot volume, Doyle. South. J. Appl. For. 18(3): 128-132.


2002 ◽  
Vol 26 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Gary D. Kronrad ◽  
Ching-Hsun Huang

Abstract A quantitative analysis of the profitability of managing loblolly pine (Pinus taeda L.) in relation to the length of rotation and the timing, frequency, and intensity of thinning(s) was conducted to determine financially optimal schedules for nonindustrial private forest landowners in Texas. The results indicate that as site index increases from 50 to 90, rotation length decreases from age 59 to 38; as real alternative rate of return (ARR) increases from 2.5 to 15.0%, rotation length decreases from age 38 to 21. The timing of first thinning varies from age 11 for landowners with a 15.0% ARR on site index 90 land to age 47 for landowners with a 2.5% ARR on site index 60 land. The frequency of thinning for optimal schedules is highly related to landowners' site index and ARR. Landowners with low and medium ARR on site index 90 land should conduct thinnings up to three times to maximize profits; landowners with low ARR on site index 50 or 60 land should conduct one thinning only. The intensity of thinning tends to increase (from 20 to 35% basal area removal) as landowners' ARR increases. South. J. Appl. For. 26(1):13–17.


Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1034
Author(s):  
Rodolfo Picchio ◽  
Farzam Tavankar ◽  
Francesco Latterini ◽  
Meghdad Jourgholami ◽  
Behroz Karamdost Marian ◽  
...  

Loblolly pine (Pinus taeda L.) is one of the main exotic conifer species that has been widely planted for the past fifty years for timber production in the coastal areas of northern Iran. Heavy snowfall and strong winds can cause much damage to these forests over a short time span of only a few years. This study was conducted to estimate snow and wind damage and analyze the role of stand thinning in their resistance to snow and wind. Amount and type of snow and wind damage were examined through systematic (80 m × 80 m) sample plots (each plot area of 625 m2) in nine different stands (2–10 plots in each stand) in terms of age, structure, and silviculture history in three replications for each stand in April and May 2020. Results showed that the amount of snow and wind damage had a wide range from 1.3% to 30.7%. Snow damage was more than three times that of wind. Snow and wind damage in the young stands were significantly more serious (p < 0.01) than in the middle-aged and old stands, and damage was significantly higher (p < 0.01) in the unthinned stands than in the thinned ones. Slenderness coefficient (Height/Diameter ratio, HD ratio) of trees resulted to be a good indicator in young and middle-aged stands, while crown form indices (relative crown length and relative crown width) were acceptable indicators in old stands for risk of snow and wind damage. Our results showed that the normal thinning (15% of basal area) decreased snow and wind damage in all the stands, while the heavy thinning (35% of basal area) reduced the snow damage, but it increased the wind one. It is possible to recommend high intensity thinning in young stands, normal thinning in middle-aged stands, and light thinning (15% of basal area) in old ones.


2000 ◽  
Vol 24 (4) ◽  
pp. 202-206
Author(s):  
David W. Patterson ◽  
Paul A. Murphy ◽  
Michael G. Shelton

Abstract Uneven-aged silviculture using single-tree selection provides the landowner with periodic income from a continuous forest which has a varied canopy. Data were collected from 24 plots of a larger study to determine if site index, basal area, and maximum dbh affected volume and value of lumber from loblolly pine (Pinus taeda L.) trees in uneven-aged stands. Tree grades and lumber yield equations were used to determine the volume of lumber by grade for each tree. Market prices from May 1997 and May 1998 were used to estimate lumber value. Analysis of variance showed that study variables significantly affected lumber volume, lumber value/mbf, and stand value/ac. With 1997 prices, increases in site index and maximum dbh significantly increased lumber value/mbf, but only maximum dbh was significant with 1998 prices. Stand values ranged from $4,100 to $12,350/ac and were significantly higher for the higher site index, basal area, and maximum dbh. South. J. Appl. For. 24(4):202-206.


1995 ◽  
Vol 25 (2) ◽  
pp. 208-214 ◽  
Author(s):  
J.S. Shumway ◽  
H.N. Chappell

The Diagnosis and Recommendation Integrated System (DRIS) has been used successfully in agricultural crops and holds promise for use in forest stands. This study used soil tests to develop DRIS norms and evaluate their effectiveness in coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forests. DRIS norms for nitrogen, phosphorus, potassium, and calcium were developed using soil test and site index data from 72 soil series that commonly support Douglas-fir in western Washington. The norms were tested using soil test and stand basal area growth response data from 20 thinned and 30 unthinned N fertilizer test sites in coastal Washington and Oregon. Response to urea fertilizer in thinned stands averaged 34% and 43% for 224 and 448 kg N•ha−1, respectively, when N was identified as the most limiting nutrient. When N was not the most limiting nutrient, N response averaged 8% and 10% for 224 and 448 kg N•ha−1, respectively. Results were similar in unthinned stands and thinned stands, although response to fertilizer appeared to be slightly less in unthinned stands when N was the most limiting nutrient. DRIS correctly classified 25 of the 33 sites (76%) where N fertilizer increased growth by more than 15%. More importantly, 13 of the 17 (76%) sites that responded by less than 15% were correctly identified by DRIS. The results clearly indicate that N fertilizer response is dependent on the interactions (balance) between soil nutrients at a given site. Future soil diagnostic work needs to focus on techniques, like DRIS, that provide an assessment of these interactions.


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