4,247 research outputs found
First-year survival and growth of bareroot and container water oak and willow oak seedlings grown at different levels of mineral nutrition
Bareroot and container water oak (Quercus nigra) and willow oak (Quercus phellos) seedlings were treated with 3 different levels of nitrogen (N) mineral fertilizer applied during the growing season in the nursery. Comparisons were made between species, N treatments, and stock-types for seedling morphology, first-year survival and height growth, and seedling water relations. Water oak seedlings were shorter, heavier, and more first-order lateral roots than the willow oak seedlings. The N fertilizer treatments did not have a statistically significant effect on seedling morphology. Bareroot seedlings were taller, had greater root-collar diameters, and were heavier than the container seedlings. The seedlings were hand-planted on an old pasture site located near Nacogdoches, TX. First-year survival was about 80 percent regardless of species, N treatment, or stocktype. Bareroot seedlings had less first-year height growth than container seedlings. Container seedlings fertilized at the highest N rate had greater stomata1 conductance and transpiration rates early in the growing season than the container seedlings fertilized at the lowest rate
Effects of flooding regime, mycorrhizal inoculation and seddling treatment type on first-year survival of nuttall oak (Quercus nuttallii PALMER)
Three different types of Nuttall oak ( Quercus nuttallii Palmer) seedlings were planted on floodprone, former cropland in Mississippi, Louisiana, and Texas. The three types of 1+0 seedlings planted at each site in January and February of 1995 were bareroot seedlings, seedlings grown in 164 square centimeters plastic containers, and containergrown seedlings inoculated with vegetative mycelia of Pisolithus tinctorious (Pers.) Coker and Couch. Seedlings at the Mississippi site were planted in a split-plot design at three different elevations, which provided three different natural flooding treatments. Seedlings at the other two sites were planted in a Latin square design at a single elevation. Significant differences in the survival and condition of the seedlings during the first growing season were observed at the Louisiana site, favoring the inoculated container-grown seedlings over the other two stock types. First-year seedling survival at the site in Texas, which had the best drainage of the three sites, was not significantly different between treatments. Small mammals clipped 98 percent of the container-grown seedlings at the Mississippi site
Effects of sower type and seedbed density on bareroot seedling morphology and early field performance of an East Texas family of loblolly pine
Precision sowing is commonly used at forest tree nurseries in order to improve the growing space uniformity of seedlings in the beds. Temple-Inland Forest Products Corporation recently purchased a vacuum sower and requested a study be conducted comparing their new sower with a drill sower on the morphological characteristics of loblolly pine (Pinus taeda L.) at lifting. The study was conducted in 2000 and repeated in 2001. The seed were sown using the two sower types to achieve four densities of 161 , 215, 269, and 323 seedlings/m2⢠Two half-sibling families were tested in 2000, and one halfsibling family was tested in 2001 . For both studies, the experimental design was a randomized complete block with four replications. Cultural practices used to grow the seedlings were typical for the nursery. The seedlings were hand-lifted mid-winter for measurements of stem height, root-collar diameter, and oven-dry biomass. For the 2001 study, seedlings were handplanted 1 week after lifting in a clearcut near Etoile, TX. The mean morphology of the seedlings was similar when comparing the two sowers. When averaged for all densities, more seedlings with small root-collar diameters (s; 3 mm) were sampled in the 2000 study from the drill sower plots than from the vacuum sower plots. For the 2001 study, slightly more seedlings with small diameters were sampled from the vacuum sower plots. At typical operational densities of 215 and 269 seedlings/m2, the use of the vacuum sower resulted in more seedlings at lifting, fewer small-diameter seedlings, and more large-diameter seedlings (~ 5 mm). As seedbed density was reduced, mean seedling root-collar diameter and oven-dry biomass increased. Seedlings grown in the nursery at 161 seedlings/m2 were taller after the first and second growing season following planting
First-year survival and growth of bareroot, container, and direct-seeded Nuttall oak planted on flood-prone agricultural fields
Container and 1-0 bare root Nuttall oak ( Quercus nuttallii, Palmer) seedlings were hand-planted, and acorns were direct- seeded, in a Sharkey soil (very fine, montmorillonitic, nonacid, thermic, Vertie Haplaquepts). The seedlings and seed were planted in January, February, March, and June, 1993. Flooding, to a depth of 2 meters, occurred on the study site from late March to late May. Seedlings planted in June were not flooded. Regardless of planting date, mean first-year survival for container seedlings was greater than 80 percent. Overall mean survival for bareroot seedlings was about 40 percent and direct-seeding survival was 30 percent. Bareroot seedling survival was about 60 percent when seedlings were planted in January or February, but fell below 25 percent when seedlings were planted in March and June. The reduction in bareroot survival was attributed to long-term cold storage. Mean first-year total height of container, bareroot, and directseeded seedlings was 46 centimeters, 34 centimeters, and 15 centimeters, respectively. However, stem dieback resulted in shorter seedlings after the first year in the field. Container seedlings were slightly shorter than when planted, but bareroot seedlings averaged 22 centimeters shorter. Greater survival and flexibility with regard to planting schedules may justify the use of container seedlings on flood-prone sites
Root Growth Potential and Field Survival of Container Loblolly Pine Seedlings Fall Fertilized with Nitrogen
Two studies investigated the effects of fall nitrogen fertilizer applications on the root growth potential (RGP) and field performance of container loblolly pine seedlings (Pinus taeda L.). The seedlings were sampled at 4 chilling levels ranging from 100 to 550 hours (0 to 8\u27 C). Seedlings propagated for the first study may have had a hidden nutrient deficiency and therefore the fall diammonium phosphate (DAP) application at rates of 202 kg N/ha and 67 kg N/ha increased RGP 43% and 32%, respectively. The growing season mineral fertilizer application rate was increased in the second study which may explain why nitrogen applications at 202 kg N fall/ha did not increase RGP. In general, RGP increased as exposure to chilling hours increased. Fall fertilization increased total seedling weight. Analysis of covariance indicated that RGP may be a function of total seedling weight and not a direct response to fertilizer treatment or chilling level. For the first study, survival was not significantly affected by the fall DAP treatments
Effects of Fall Fertilizer Applications of Mitotic Index and Bud Dormancy of Loblolly Pine Seedlings
A series of studies examined the effects of fall fertilization with diammoniwn phosphate (DAP) on mitotic index and bud donnancy [as measured by mean days to budbreak (DBB)] of two half-sib seed sources of loblolly pine. The first study tested different rates of DAP (0, 67, and 202 kg Nlha), the second study compared DAP with ammoniwnnitrate, and the third study examined the effect of different application dates (September 28, October 19, and November 9). An increase in mitotic index of unfertilized seedlings was observed during October and was due to developmental activity which follows initial budset. Differences in mitotic index were observed between families in all three studies.Overall, the Georgia family has a higher mitotic index, but in one study, the Virginia family had higher values in the spring. Both families tended to reach a minimum level of mitotic index at the same time (mid- to late December). However, the Virginia family reached maximum rest (as measured by days to bud break) about 1 to 2 weeks prior to the Georgia
family. Fertilization with DAP in the fall (after bud set in September) did not delay the progression of the bud dormancy cycle as measured by days to bud break in a greenhouse. The overall effect of fall fertilization on increasing the mitotic index was temporary and only lasted for about three weeks after fertilization. These findings indicated that a direct relationship may not exist between the bud dormancy cycle and mitotic index
Effects of Stock Type and Fall Fertilization on Survival of Longleaf Pine Seedlings Planted in Lignite Minespoil
One-year-old longleaf pine (Pinus palustris Mill.) seedlings were hand-planted in January 1996 on an east Texas minespoil site. Effects of two seedling stock types and four levels of preplanting fall fertilization on seedling survival were evaluated. Fertilizer treatments consisting of a single application of ammonium nitrate (73 kilograms per hectare N), phosphorus (81 kilograms per hectare P), diammonium phosphate (73 kilograms per hectare N, 81 kilograms per hectare P), or control (no fertilizer) were applied to bare-root and container seedlings in November 1995. Root growth potential, the ability of a seedling to initiate and elongate new roots when placed into a favorable environment, was measured at time of planting. Field survival was surveyed monthly beginning in April 1996. Data were examined using analysis of variance. Container seedlings had significantly higher root growth potential and survival than bare-root. Fertilizer treatment effects, while not significant, tended to decrease both root growth potential and early survival for bare-root seedlings, and to increase root growth potential and decrease survival for container seedlings. Drought conditions during the 1996 growing season probably had a negative effect on survival of both bare-root and container seedlings. Only 2 percent of bare-root and 56 percent of container seedlings survived through the growing season, suggesting that only container stock should be used for reforestation of longleaf on minespoil sites. However, in years with normal precipitation, stock type effects on survival may not be significant and planting bare-root seedlings may be a viable option
The Response of Bareroot Loblolly Pine Seedlings to the Amount and Timing of Nitrogen Fertilization in the Nursery
A nursery study was conducted to observe the effects of altering the amount of nitrogen fertilizer at each application on bareroot loblolly pine (Pinus taeda L.) seedling morphology, survival and growth. The treatments were an equal amount of fertilizer applied each time, an increasing amount each time, and a schedule characterized by low amounts, high amounts, and low amounts. Six applications of ammonium nitrate (32.5 percent N) were applied between June and August 2000, and for all treatments, a total of 169 kg N per ha was applied. In addition, for each growing season treatment, the seedlings were treated either in October or November with a one-time application of 56 kg N per ha or 113 kg N per ha as ammonium nitrate. The seedlings were lifted in January 2001, for morphology measurements and field planting. The seedlings treated with an increasing amount of N during the growing season had greater foliage, stem and root weights. Seedlings treated with 113 kg N per ha in October had the largest root collar diameters. First-year survival exceeded 90 percent for all treatments. First-year height growth was greatest for the seedlings that received 113 kg N per ha in October in the nursery
Initial establishment success of five forages in an east Texas loblolly pine (Pinus taeda) silvopasture
The establishment at the end of 1 year of five forages was evaluated in a loblolly pine (Pinus taeda L.) silvopasture system. The five forages were: âPensacolaâ bahiagrass (Paspalum notatum Fluegge), âTexas Toughâ bermudagrass (Cynodon dactylon L. Pers.), âAlamoâ switchgrass (Panicum virgatum L.), âSan Marcosâ Eastern gamagrass (Tripsacum dactyloides L.), and a native mix containing 45% âTexasâ little bluestem (Schizachyrium scoparium Michx Nash), 15% sand lovegrass (Eragrostis trichodes Nutt. L. Alph. Wood), 15% âBlackwellâ switchgrass (Panicum virgatum L.), 10% âLometaâ indiangrass (Sorgastrum nutans L. Nash), 10% âHaskellâ sideoats grama (Bouteloua curtipendula Michx Torr) and 5% âEarlâ big bluestem (Andropgon gerardii Vitman) by weight.
The silvopasture was in a 22 year old stand of loblolly pine in the Fairchild State Forest near Rusk, Texas. Five plots for each forage were sown in March 2008 and the density of each forage after one year calculated. Soil samples were taken to a depth of 10 cm from each corner of each plot using a push probe sampler and a composite sample created for chemical analyses Soil depth to B horizon or restrictive layer was determined using an 8 cm diameter hand bucket auger. In addition, light quality under the canopy was evaluated in August, October and January using a hand-held spectroradiometer: for light quality analysis, light was divided into blue, green, red, and far red bands. Irradiance (Îźmol photons m-2 s-1) for each band was divided by the total for all bands to create a proportion.
Soil depth was positively correlated to plant density in the silvopasture. Bahiagrass and Eastern gamagrass were well established after one growing season. Compared to full sun, light intensity in the silvopasture was reduced by 29% in August, 51% in October, and 56% in January. Proportion and light intensity of the far red band decreased from August to January. Light quality was not affected by the canopy; but the intensity of light reflected or absorbed by the canopy decreased between August and January. Light readings may have been influenced by the decrease in solar angle from August to January. Light intensity was higher than the light compensation point, but lower than the light saturation point for several of the grasses; light in the silvopasture was lowest in January when warm season forages are generally dormant
Assessing the Efficacy of MODIS Satellite-derived Start of Growing Season for Jurisdictional Determination of East Texas Bottomland Hardwood Wetlands
Introduction: Crucial to the determination of a jurisdictional wetland is the definition of âgrowing seasonâ. Satellite imagery is being utilized in other ecological applications, but is lagging in wetland growing season determination. Both cost and temporal limitations historically have restrained use of satellite imagery in assessing the start up of the growing season. Multiple commercial satellites are available that provide high resolution imagery, but the cost are prohibitive for most studies. The National Aeronautics and Space Administration (NASA) and the U.S. Geological Survey (USGS) jointly manage the Landsat and the Moderate-resolution Imaging Spectroradiometer (MODIS) satellite programs. Landsat Enhanced Thematic Mapper Plus images an area every sixteen (16) days. The rapid biological changes indicating the start up of the growing season must be captured more frequently to successfully use satellite imagery for such a time dependent event. In 1999 NASA launched the MODIS program with the Terra satellite and followed with the Aqua satellite in 2000. Terraâs orbit around the Earth is timed so that it passes from north to south across the equator in the morning. Aqua will pass south to north over the equator in the afternoon. This continual, comprehensive coverage allows MODIS to complete an electromagnetic picture of the globe every day. MODIS imagery is available on a daily basis, but the trade-off for the increased speed at which the satellites travel is a lower resolution image when compared to other satellite systems. Research utilizing MODIS for studying vegetation phenology is beginning to emerge, but there is a lack of validation through ground observation for these studies. (Figure 1 and Figure 2
- âŚ