Annual fertilization and interspecific competition control: effects on in situ forest floor nitrogen fluxes of different-aged Pinus taeda stands in southeast Georgia, USA

2004 ◽  
Vol 34 (9) ◽  
pp. 1802-1818 ◽  
Author(s):  
Dean F Meason ◽  
Daniel Markewitz ◽  
Rodney E Will
Keyword(s):  
Interspecific Competition ◽  
Pinus Taeda ◽  
Forest Floor ◽  
Organic N ◽  
Stand Age ◽  
Inorganic N ◽  
Competition Control ◽  
Pinus Taeda L ◽  
The Impact ◽  
N Flux

Forest floor organic matter in managed pine forests can accumulate large quantities of N during early stand development. The conversion of the forest floor from a net accumulator to a net source of N as stands age, however, is not well quantified, nor is the effect of management activities on this conversion process. Nitrogen flux from the forest floor of different-aged Pinus taeda L. stands (8, 12, and 14 years old) was measured to understand the impact of annual fertilization (~70 kg N·ha–1·year–1) and complete interspecific competition control on forest floor N cycling. Throughfall and forest floor leachate solutions were collected for 1 year and N mineralization assays conducted. Volume-weighted mean concentrations were used in conjunction with hydrologic fluxes to estimate the net nitrate (NO3–-N), ammonium (NH4+-N), and dissolved organic N flux from the forest floor. Complete competition control had no effect on the inorganic N flux. Changes in inorganic or organic N flux also were not discernable with stand age. Fertilization treatments, excluding fertilizer pulses, significantly increased the forest floor release of N in the fertilized stands compared with the nonfertilized stands (p < 0.05). Overall fluxes of NO3–-N and NH4+-N from the forest floor were, respectively, 2.8 and 6.2 kg N·ha–1·year–1 for fertilized stands and –1.1 and 0.9 kg N·ha–1·year–1 for nonfertilized stands. Unlike inorganic N, organic N was retained in fertilized stands as a result of large organic throughfall inputs. Nitrogen cycling through the forest floor was ~4 kg·ha–1·year–1 greater in fertilized stands. This increased N release may account for as much as 6% of average annual pine demand and thus may well enhance productivity in future years.

Effects of competition control and annual nitrogen fertilization on gas exchange of different-aged Pinus taeda

2003 ◽  
Vol 33 (6) ◽  
pp. 1076-1083 ◽  
Author(s):  
Gregory T Munger ◽  
Rodney E Will ◽  
Bruce E Borders
Keyword(s):  
Gas Exchange ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Positive Impact ◽  
Leaf Gas Exchange ◽  
Nitrogen Concentration ◽  
Net Photosynthesis ◽  
Stand Age ◽  
Competition Control ◽  
Pinus Taeda L

To determine the importance of competition control and annual fertilization on leaf gas exchange, light-saturated net photosynthesis (Asat), stomatal conductance (gs), and internal CO2 concentration (Ci) were measured multiple times in different-aged loblolly pine (Pinus taeda L.) stands growing at a Piedmont (BF Grant) and Coastal Plain (Waycross) location in Georgia, U.S.A. At both locations, competition control decreased Asat and gs (Asat from 4.53 to 4.12 µmol·m–2·s–1, gs from 0.058 to 0.050 mol·m–2·s–1 at BF Grant; Asat from 4.22 to 4.01 µmol·m–2·s–1, gs from 0.054 to 0.049 mol·m–2·s–1 at Waycross). Overall, fertilization did not have a positive impact on Asat, even though fertilization significantly increased foliar nitrogen concentration. At BF Grant, fertilization significantly decreased gs from 0.057 to 0.051 mol·m–2·s–1 and Ci from 217 to 205 µmol·mol–1. In addition, the decrease in Ci associated with fertilization became larger with stand age. At Waycross, fertilization decreased Ci from 211 to 203 µmol·mol–1 and the interaction between fertilization and stand age was significant for gs and Ci. These results indicate that silivcultural practices that increase resource availability and stand growth did not enhance leaf gas exchange.

scholarly journals Dynamic of nitrogen and dissolved organic carbon in an alpine forested catchment: atmospheric deposition and soil solution trends

2019 ◽  
Vol 34 ◽  
pp. 41-66 ◽  
Author(s):  
Raffaella Balestrini ◽  
Carlo Andrea Delconte ◽  
Andrea Buffagni ◽  
Alessio Fumagalli ◽  
Michele Freppaz ◽  
...  
Keyword(s):  
Soil Solution ◽  
Forest Ecosystem ◽  
Forest Floor ◽  
Mineral Soil ◽  
Chemical Species ◽  
Organic N ◽  
Seasonal Temperature ◽  
Inorganic N ◽  
Forest Floor Leachates ◽  
Throughfall Deposition

A number of studies have reported decreasing trends of acidifying and N deposition inputs to forest areas throughout Europe and the USA in recent decades. There is a need to assess the responses of the ecosystem to declining atmospheric pollution by monitoring the variations of chemical species in the various compartments of the forest ecosystem on a long temporal scale. In this study, we report on patterns and trends in throughfall deposition concentrations of inorganic N, dissolved organic N (DON) and C (DOC) over a 20-year (1995–2015) period in the LTER site -Val Masino (1190 m a.s.l.), a spruce forest, in the Central Italian Alps. The same chemical species were studied in the litter floor leachates and mineral soil solution, at three different depths (15, 40 and 70 cm), over a 10-year period (2005–2015). Inorganic N concentration was drastically reduced as throughfall and litter floor leachates percolated through the topsoil, where the measured mean values (2 µeq L-1) were much lower than the critical limits established for coniferous stands (14 µeq L-1). The seasonal temperature dependence of throughfall DOC and DON concentration suggests that the microbial community living on the needles was the main source of dissolved organic matter. Most of DOC and DON infiltrating from the litter floor were retained in the mineral soil. The rainfall amount was the only climatic factor exerting a control on DOC and N compounds in throughfall and forest floor leachates over a decadal period. Concentration of SO4 and NO3 declined by 50% and 26% respectively in throughfall deposition. Trends of NO3 and SO4 in forest floor leachates and mineral soil solution mirrored declining depositions. No trends in both DON and DOC concentration and in DOC/DON ratio in soil solutions were observed. These outcomes suggest that the declining NO3 and SO4 atmospheric inputs did not influence the dynamic of DON and DOC in the Val Masino forest. The results of this study are particularly relevant, as they are based on a comprehensive survey of all the main compartments of the forest ecosystem. Moreover, this kind of long-term research has rarely been carried out in the Alpine region.

The Influence of Woody and Herbaceous Competition on Early Growth of Naturally Regenerated Loblolly and Shortleaf Pines

1991 ◽  
Vol 15 (4) ◽  
pp. 179-185 ◽  
Author(s):  
M. D. Cain
Keyword(s):  
Pinus Taeda ◽  
Woody Plants ◽  
Early Growth ◽  
The Other ◽  
Herbaceous Plants ◽  
Herbaceous Vegetation ◽  
Competition Control ◽  
Total Control ◽  
Four Levels ◽  
Pinus Taeda L

Abstract Four levels of competition control were used to study the response of naturally regenerated loblolly and shortleaf pines (Pinus taeda L. and P. echinata Mill.) in southern Arkansas. Treatments included: (1) Check (no competition control), (2) woody competition control, (3) herbaceous competition control, and (4) total control of nonpine vegetation. Herbaceous plants were controlled for 4 consecutive years, and woody plants were controlled for 5 years. Control of herbaceous vegetation resulted in significant increases in pine height, groundline diameter (GLD), and volume per tree. Control of only woody competition did not improve pine growth compared to untreated checks. After 5 years, pines on total control plots had significantly larger GLDs and significantly more volume per tree compared to pines on any other treatment. Pine growth gains were achieved with herbaceous competition control and total control of nonpine vegetation although these two treatments averaged 4,000 more pines/ac, in trees taller than 5 ft, than the other two treatments. Results of this investigation represent a unique standard of pine growth to which operational treatments might be compared. South. J. Appl. For. 15(4):179-185.

scholarly journals Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It

2021 ◽  
Author(s):  
Yinliu Wang ◽  
Signe Lett ◽  
Kathrin Rousk
Keyword(s):  
Boreal Forests ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Ecosystem Functions ◽  
Organic N ◽  
Inorganic N ◽  
Atmospheric N Deposition ◽  
Moss Species ◽  
The Impact ◽  
N Additions

Abstract Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha−1 yr−1) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha−1 yr−1) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

Basal Area and Diameter Distribution Models for Loblolly Pine Plantations with Hardwood Competition in the Piedmont and Upper Coastal Plain

1992 ◽  
Vol 16 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Steven A. Knowe
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Coastal Plain ◽  
Basal Area ◽  
Simulation Models ◽  
Diameter Distribution ◽  
Distribution Models ◽  
Pinus Taeda L ◽  
The Impact ◽  
Volume Equations

Abstract Prediction equations were developed for basal area and percentiles of diameter distributions to account for the hardwood component in site-prepared, Piedmont and Upper Coastal Plain loblolly pine (Pinus taeda L.) plantations. Unlike existing stand-level simulation models that incorporate hardwood competition, the new equations resulted in constant total basal area regardless of the amount of hardwood competition and permitted the variance of the diameter distribution to increase with increasing proportion of hardwoods. The equations presented can be used with existing dominant height, survival, and volume equations as a tool for assessing the impact of hardwoods on loblolly pine yield. South. J. Appl. For. 16(2):93-98.

scholarly journals Effects of Early Release on Natural Versus Container Loblolly Pines 12 Years After Field Establishment

2002 ◽  
Vol 26 (4) ◽  
pp. 173-180 ◽  
Author(s):  
Michael D. Cain ◽  
James P. Barnett
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Early Release ◽  
Percentage Points ◽  
Competition Control ◽  
Genetically Improved ◽  
Loblolly Pines ◽  
Pinus Taeda L

Abstract Genetically improved, container loblolly pine (Pinus taeda L.) seedlings were compared to naturally established loblolly seedlings on a cutover pine site. Crop pines on 6 of 12 plots were released from woody and herbaceous competition within a 2 ft radius of each stem. On release plots, woody competition was controlled by hand-cutting for 5 consecutive yr and herbaceous competition was controlled with herbicides for 4 consecutive yr after pine establishment. Competition control increased 12 yr survival by 68 percentage points for natural pines and by 47 percentage points for planted pines. Twelve years after field establishment, mean-tree volume of planted pines was no different than that of naturally established pines. Nevertheless, volume gains of 150% to 200% were achieved within regeneration techniques as a result of release. South. J. Appl. For. 26(4):173–180.

Woody and herbaceous competition effects on stand dynamics and growth of 13-year-old natural, precommercially thinned loblolly and shortleaf pines

1999 ◽  
Vol 29 (7) ◽  
pp. 947-959 ◽  
Author(s):  
Michael D Cain
Keyword(s):  
Pinus Taeda ◽  
Coastal Plain ◽  
Stand Dynamics ◽  
Vegetation Control ◽  
Competition Control ◽  
Loblolly Pines ◽  
Volume Production ◽  
The Mean ◽  
Four Levels ◽  
Pinus Taeda L

Stand dynamics of naturally regenerated, even-aged, loblolly pines (Pinus taeda L.) and shortleaf pines (P. echinata Mill.) were examined on the Upper Coastal Plain of southeastern Arkansas, U.S.A., following four levels of competition control. Treatments included a check (Ck) with no competition control, woody control (WC), herbaceous control (HC), and total control (TC) of nonpine vegetation. After pines became established from natural seeding, herbicides were used to control herbaceous plants for four consecutive years and woody plants for five consecutive years. At age five, 1235 crop pines/ha were retained and all noncrop pines >1.5 m tall were precommercially hand thinned. Although 93% of crop pines on Ck plots were judged free-to-grow 13 years after establishment, crop pines on vegetation control plots were larger (P [Formula: see text] 0.001) in mean diameter at breast height, total height, and volume per tree. From age 5 through 13 years, crop pine diameter growth increased on WC plots and decreased on HC plots because of hardwood competition in the latter treatment. At age 13, mean pine volume production was 48% greater (P < 0.01) on plots that received competition control than on Ck plots (160 m3·ha-1); TC resulted in 31% more (P < 0.01) volume (282 m3·ha-1) than the mean of WC and HC plots; and there was no difference (P = 0.15) between the latter two treatments.

Soil CO2 evolution and root respiration in 11 year-old loblolly pine (Pinus taeda) plantations as affected by moisture and nutrient availability

2000 ◽  
Vol 30 (3) ◽  
pp. 347-359 ◽  
Author(s):  
C A Maier ◽  
L W Kress
Keyword(s):  
Carbon Source ◽  
Soil Temperature ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Forest Floor ◽  
Root Respiration ◽  
Carbon Sink ◽  
Annual Carbon ◽  
The Difference ◽  
Pinus Taeda L

We measured soil CO2 evolution rates with (Sff) and without (Sms) the forest floor litter and root respiration monthly in 11-year-old loblolly pine (Pinus taeda L.) plantations during the fourth year of fertilization and irrigation treatments. Values of Sff ranged from less than 1 µmol·m-2·s-1 during the winter to greater than 5 µmol·m-2·s-1 in late spring. Average Sff was significantly greater in unfertilized relative to the fertilized stands; however, there was no difference in average Sms among treatments. Soil temperature and the mass of the forest floor (litter) explained most of the difference in Sff among treatments. Soil temperature and volumetric water content accounted for 70% of the seasonal variation in Sff. Annual carbon efflux from the soil averaged 14.1 Mg·ha-1 per year for all treatments. Most of the evolved carbon was derived from root respiration (50-73%). Net ecosystem productivity was -1.1 and 6.9 Mg C·ha-1 per year for the unfertilized and fertilized stands, respectively. At age 11, the unfertilized stands were functioning as a net carbon source, while fertilized stands were a strong carbon sink. It was concluded that fertilization could decrease the time for a young pine plantation to change from a carbon source to a carbon sink.

Four-Year Growth and Development of Planted Loblolly Pine on Sites with Competition Control

1985 ◽  
Vol 9 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Steven A. Knowe ◽  
Larry R. Nelson ◽  
Dean H. Gjerstad ◽  
Bruce R. Zutter ◽  
Glenn R. Glover ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Weed Control ◽  
Loblolly Pine ◽  
Coastal Plain ◽  
Growth And Development ◽  
East Central ◽  
Competition Control ◽  
Pinus Taeda L

Abstract The effects of competition on loblolly pine (Pinus taeda L.) development during the initial 4 years of a plantation were investigated on an Upper Coastal Plain site in east-central Alabama. Height and diameter response to competition control in relation to time following treatment and amount of herbaceous competition were examined. Trees on plots receiving broadcast weed control for 2 years were twice the height and diameter of trees with no weed control after 4 years, while trees receiving banded weed control for 2 years were 1.6 times taller and 1.75 times larger in diameter. Broadcast and banded 1-year treatments were 1.4 times larger in both measures.

Effects of annual fertilization and complete competition control on current annual increment, foliar development, and growth efficiency of different aged Pinus taeda stands

2002 ◽  
Vol 32 (10) ◽  
pp. 1728-1740 ◽  
Author(s):  
Rodney E Will ◽  
Gregory T Munger ◽  
Yujia Zhang ◽  
Bruce E Borders
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Coastal Plain ◽  
Growth Efficiency ◽  
Tree Size ◽  
Stand Age ◽  
Leaf Biomass ◽  
Age Difference ◽  
Annual Increment ◽  
Competition Control

The effects that competing vegetation and nitrogen limitation have on the current annual increment (CAI), leaf biomass, and growth efficiency (GE) of different aged loblolly pine (Pinus taeda L.) stands planted on a Piedmont and lower Coastal Plain location in Georgia, U.S.A. were determined by measuring stands receiving a factorial combination of complete interspecific competition control and annual nitrogen fertilization. At the Piedmont location, CAI increased with age (5, 10, and 12 years) as well as fertilization (7.3–9.2 Mg·ha–1) and competition control (6.8–9.6 Mg·ha–1). The effects of fertilization on leaf biomass increased with stand age (no difference at age 5 to 1.5 Mg·ha–1 difference at age 12), while the effects of competition control on leaf biomass decreased with stand age (difference of 2.5 Mg·ha–1 at age 5 to difference of 1.6 Mg·ha–1 at age 12). At the Coastal Plain location, fertilization increased CAI from 10.3 to 14.8 Mg·ha–1. Leaf biomass increased with competition control (4.9–5.5 Mg·ha–1) and fertilization (4.4–6.0 Mg·ha–1). Leaf biomass increased with stand age for the fertilized stands (5.3–7.0 Mg·ha–1 between age 7 and 13) and decreased with stand age for nonfertilized stands (4.9–4.0 Mg·ha–1 between age 7 and 13). At the Coastal Plain location, fertilization increased the GE of the age-7 stands from 2.34 to 2.86 but decreased the GE of the age-13 stands from 2.32 to 2.14. In general, GE decreased as mean tree size increased indicating that changes in GE related to treatments may be confounded with changes in tree size. Results of this experiment emphasize the importance of nutrition on stand growth as fertilization increased leaf biomass and may increase stem production per unit of foliage at early stages of development.

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