Site preparation burning to improve southern Appalachian pine–hardwood stands: photosynthesis, water relations, and growth of planted Pinusstrobus during establishment

1993 ◽  
Vol 23 (10) ◽  
pp. 2278-2285 ◽  
Author(s):  
Katherine J. Elliott ◽  
James M. Vose
Keyword(s):  
Soil Water ◽  
Photosynthetic Capacity ◽  
Net Photosynthesis ◽  
Growing Season ◽  
Southern Appalachians ◽  
Xylem Water Potential ◽  
Clear Cut ◽  
Foliar N ◽  
Southern Appalachian ◽  
Foliar N Concentration

We examined the physiological performance and growth of Pinusstrobus L. seedlings the first growing season after planting on two clear-cut and burned sites in the southern Appalachians. Growth of the seedlings was related to physiological measurements (net photosynthesis (PN), transpiration, leaf conductance, and xylem water potential), soil water, foliar N, seedling temperature, and light environment using regression analysis. Diameter growth increased with increasing foliar N concentration and decreased as competitor biomass increased. Competition reduced growth by lowering foliar N, shading seedlings, and possibly reducing photosynthetic capacity. Increased temperature and lower available soil water may obscure these relationships on a harsh site.

scholarly journals Characterizing Growing Season Length of Subtropical Coniferous Forests with a Phenological Model

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 95
Author(s):  
Yuan Gong ◽  
Christina L. Staudhammer ◽  
Susanne Wiesner ◽  
Gregory Starr ◽  
Yinlong Zhang
Keyword(s):  
Climate Change ◽  
Soil Water ◽  
Prescribed Fire ◽  
Water Availability ◽  
Longleaf Pine ◽  
Growing Season ◽  
Soil Water Availability ◽  
Future Climate Change ◽  
Short Term ◽  
Phenological Model

Understanding plant phenological change is of great concern in the context of global climate change. Phenological models can aid in understanding and predicting growing season changes and can be parameterized with gross primary production (GPP) estimated using the eddy covariance (EC) technique. This study used nine years of EC-derived GPP data from three mature subtropical longleaf pine forests in the southeastern United States with differing soil water holding capacity in combination with site-specific micrometeorological data to parameterize a photosynthesis-based phenological model. We evaluated how weather conditions and prescribed fire led to variation in the ecosystem phenological processes. The results suggest that soil water availability had an effect on phenology, and greater soil water availability was associated with a longer growing season (LOS). We also observed that prescribed fire, a common forest management activity in the region, had a limited impact on phenological processes. Dormant season fire had no significant effect on phenological processes by site, but we observed differences in the start of the growing season (SOS) between fire and non-fire years. Fire delayed SOS by 10 d ± 5 d (SE), and this effect was greater with higher soil water availability, extending SOS by 18 d on average. Fire was also associated with increased sensitivity of spring phenology to radiation and air temperature. We found that interannual climate change and periodic weather anomalies (flood, short-term drought, and long-term drought), controlled annual ecosystem phenological processes more than prescribed fire. When water availability increased following short-term summer drought, the growing season was extended. With future climate change, subtropical areas of the Southeastern US are expected to experience more frequent short-term droughts, which could shorten the region’s growing season and lead to a reduction in the longleaf pine ecosystem’s carbon sequestration capacity.

Red spruce seedling gas exchange in response to elevated CO2, water stress, and soil fertility treatments

1994 ◽  
Vol 24 (5) ◽  
pp. 954-959 ◽  
Author(s):  
L.J. Samuelson ◽  
J.R. Seiler
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Soil Fertility ◽  
Net Photosynthesis ◽  
Growing Season ◽  
Red Spruce ◽  
Fertility Treatment ◽  
Sink Strength ◽  
Growth Enhancement ◽  
Growing Seasons

The interactive influences of ambient (374 μL•L−1) or elevated (713 μL•L−1) CO2, low or high soil fertility, well-watered or water-stressed treatment, and rooting volume on gas exchange and growth were examined in red spruce (Picearubens Sarg.) grown from seed through two growing seasons. Leaf gas exchange throughout two growing seasons and growth after two growing seasons in response to elevated CO2 were independent of soil fertility and water-stress treatments, and rooting volume. During the first growing season, no reduction in leaf photosynthesis of seedlings grown in elevated CO2 compared with seedlings grown in ambient CO2 was observed when measured at the same CO2 concentration. During the second growing season, net photosynthesis was up to 21% lower for elevated CO2-grown seedlings than for ambient CO2-grown seedlings when measured at 358 μL•L−1. Thus, photosynthetic acclimation to growth in elevated CO2 occurred gradually and was not a function of root-sink strength or soil-fertility treatment. However, net photosynthesis of seedlings grown and measured at an elevated CO2 concentration was still over 2 times greater than the photosynthesis of seedlings grown and measured at an ambient CO2 concentration. Growth enhancement by CO2 was maintained, since seedlings grown in elevated CO2 were 40% larger in both size and weight after two growing seasons.

Growth and N status of Populus in mixture with red alder on recent volcanic mudflow from Mount Saint Helens

1990 ◽  
Vol 20 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Paul E. Heilman
Keyword(s):  
Late Summer ◽  
Height Growth ◽  
Phosphorus Fertilization ◽  
Cross Sectional ◽  
Red Alder ◽  
Total N ◽  
Foliar N ◽  
N Concentration ◽  
The Mean ◽  
Foliar N Concentration

Eleven months after the May 1980 eruption of Mount Saint Helens in southeastern Washington, United States, three Populus clones were planted in an experiment on the Toutle River mudflow deposit. The trees grew at an abnormally slow rate and by 3 years were overtopped by a dense stand (14 600 ± 3600 trees/ha) of red alder seeded naturally onto the site. Over the 6-year period of the study, the total N content of the soil increased an average of 56 kg•ha−1•year−1•. Foliar N concentration in Populus increased significantly from a mean late summer – early autumn value in the 2nd year (1982) of 0.69% N to a value of 2.06% N at the end of the seventh growing season. The mean annual height growth of the largest Populus averaged <0.5 m/year in the first 3 years, increasing to an average of over 1.0 m/year in the 5th and 6th years. Fertilizer treatments with N (as urea) and N + P (as urea plus treble superphosphate) placed in the soil near the individual Populus at a maximum rate of 5.3 g N/tree increased height growth in the year of fertilization (1982) and the following year (the response in height growth for the 2 years totaled 64%). After 1984, no significant effects of fertilizer on height growth, total height, or diameter were evident. Nitrogen fertilization significantly increased foliar N concentration (1.54% N with the highest N treatment vs. 0.69% N in the control) in the year of treatment only. Phosphorus fertilization had no significant effect on growth or foliar P concentration. At 6 years, only 2% of the Populustrichocarpa Torr. & Gray clone and 13% of the tallest Populus hybrid were equal to or above the mean height of alder dominants and codominants (6.2 m). Additionally, the diameter growth of Populus was severely limited: the trees had only 8% of the cross-sectional area of "normal" trees for their height. Results indicated that on sites of low N such as the mudflow, Populus may not compete satisfactorily in mixture with alder. Such behavior is in sharp contrast to sites of high N, where red alder cannot compete with Populus.

Soil water retention dynamics in a Mollisol during a maize growing season under contrasting tillage systems

2021 ◽  
Vol 209 ◽  
pp. 104953
Author(s):  
Xinjun Huang ◽  
Hengfei Wang ◽  
Meng Zhang ◽  
Rainer Horn ◽  
Tusheng Ren
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Growing Season ◽  
Soil Water Retention ◽  
Tillage Systems

scholarly journals Effects of five years of frequent N additions, with or without acidity, on the growth and below-ground dynamics of a young Sitka spruce stand growing on an acid peat: implications for sustainability

2004 ◽  
Vol 8 (3) ◽  
pp. 377-391 ◽  
Author(s):  
L. J. Sheppard ◽  
A. Crossley ◽  
F. J. Harvey ◽  
U. Skiba ◽  
P. Coward ◽  
...  
Keyword(s):  
Soil Water ◽  
Positive Response ◽  
Base Cation ◽  
Sitka Spruce ◽  
Organic Soil ◽  
N Deposition ◽  
Foliar N ◽  
Below Ground ◽  
Four Blocks ◽  
S Deposition

Abstract. A field manipulation study was established to demonstrate effects of simulated wet N and S deposition on a young (planted 1986) stand of Sitka spruce growing on a predominantly organic soil in an area of low (8–10 kg N ha-1 yr-1) background N deposition in the Scottish borders. From 1996, treatments (six) were applied to the canopies of ten-tree plots in each of four blocks. N was provided as NH4NO3, either with H2SO4 (pH 2.5) at 48 or 96 kg N ha-1 yr-1 inputs or without, at 48 kg N ha-1 yr-1 along with wet (rain water) and dry controls (scaffolding) and a S treatment (Na2SO4). Positive responses (+ >20% over 5 years) with respect to stem area increment were measured in response to N inputs, irrespective of whether acid was included. The positive response to N was not dose related and was achieved against falling base cation concentrations in the foliage, particularly with respect to K. The results suggest young trees are able to buffer the low nutrient levels and produce new growth when there is sufficient N. Inputs of 96 kg N ha-1 yr-1, in addition to ambient N inputs, on this site exceeded tree demand resulting in elevated foliar N, N2O losses and measurable soil water N. These excessive N inputs did not reduce stem area growth. Keywords: acid, canopy application, nitrogen, acid organic soil, simulated wet deposition, soil water, sulphur, young Sitka spruce

scholarly journals Oak Regeneration in the Southern Appalachians: Potential, Problems, and Possible Solutions

1998 ◽  
Vol 22 (1) ◽  
pp. 11-18 ◽  
Author(s):  
James E. Cook ◽  
Terry L. Sharik ◽  
David Wm. Smith
Keyword(s):  
Review Article ◽  
Oak Forests ◽  
Southern Appalachians ◽  
Limiting Factor ◽  
Oak Regeneration ◽  
Advance Regeneration ◽  
Southern Appalachian ◽  
Stump Sprouting ◽  
Low Levels ◽  
A Site

Abstract Despite the large volumes written about "oak regeneration problems" on mesic sites, very little has been presented on the extent of regional variation in oak regeneration. In this review article, we examine several important facets of oak regeneration for the Southern Appalachian region. We conclude that: (1) the amount of reproduction (seedlings and/or sprouts) is seldom a limiting factor because these oak forests have an average advance regeneration density of more than 9000/ha; (2) about 75% of all oak stems sprout after harvesting, which; (3) makes stump sprouts a major source of oak regeneration and a more important component than in the Midwest; (4) harvesting usually leads to an increase in the number of oak seedlings on a site (mean density for the first 3 yr equals 15,750/ha); (5) on sites of SI50 = 17-19m, oaks typically make up 25-40% of the canopy 2-3 decades after a harvest; (6) on sites of SI > 20m, clearcutting leads to very low levels (~10%) of oak representation in the subsequent forest, whereas a shelterwood harvest will result in 25-30% oak abundance; and (7) a harvest of an oak-dominated forest, without any other treatments, will lead to a 50-70% decline in oak. These results suggest that there is ample potential to regenerate current oak forests to oak, but new trials are needed with more species and on a greater range of sites. Increasing the size of the advance regeneration and maximizing stump sprouting are two ways to increase the amount of oak after harvest. However, regeneration cuts by themselves will not assure maintenance of the oak component; several treatments that have shown promise—midstory manipulation, fire, and weeding—are recommended for further study. South. J. Appl. For. 22(1):11-18.

Change in photosynthesis and water relations with age and season in Abiesamabilis

1984 ◽  
Vol 14 (1) ◽  
pp. 77-84 ◽  
Author(s):  
R. O. Teskey ◽  
C. C. Grier ◽  
T. M. Hinckley
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Relations ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Xylem Water Potential ◽  
Needle Age ◽  
Stressful Environment ◽  
Competitive Success ◽  
One Year

Seasonal changes in water relations and net photosynthesis were measured over a year in current and 1-year-old foliage of Abiesamabilis (Dougl.) Forbes, a subalpine conifer. Responses were compared with maximum rates achieved in older foliage. Current-year foliage developed slowly during the growing season. Although growth began on 22 June, highest rates of stomatal conductance and net photosynthesis did not occur until September and October. One-year-old foliage had the highest rates of net photosynthesis (12.9 mg CO2•dm−2•h−1) and stomatal conductance (3.1 mm•s−1) during the summer. Net photosynthesis decreased with needle age, but foliage as old as 7 years had rates of net photosynthesis as high as 5.0 mg CO2•dm−2•h−1. There was no evidence of photosynthetic adjustment to seasonal change in temperature. The optimum temperature for photosynthesis remained at 15 ± 1.5 °C throughout the year. No water stress was observed during the summer. Xylem water potential never decreased below −1.65 MPa and was always well above the turgor loss point. The lack of any apparent water stress, combined with photosynthetic characteristics, indicated that summer was the most important season for carbon gain. These results also suggested that a strategy for competitive success by Abiesamabilis in this cold, stressful environment is minimum dependence on the carbon gain of any individual age-class of foliage. Instead trees rely on the combined photosynthetic capacity of many years of foliage.

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