Bare-root Seedlings Research Articles

Survival and competitiveness of Quercus rubra regeneration associated with planting stocktype and harvest opening intensity

Successful regeneration of northern red oak (Quercus rubra L.) on productive sites is problematic in eastern North American forests. Natural and artificial regeneration often cannot compete with fast-growing, shade intolerant species such as yellow-poplar (Liriodendron tulipifera L.). This study examines 5-year survival, growth, and competitive ability of planted northern red oak seedlings in various group selection harvest sizes in south-central Indiana, USA. Seedling stocktypes consisted of high (BHD; 75 seedlings m−2) and low (BLD; 21 seedlings m−2) nursery-bed-density bareroot seedlings, and small (CS; 11.4 L) and large (CL; 18.9 L) container seedlings. Group selection openings included large (0.400 ha), medium (0.100 ha), and small (0.024 ha) circular gaps in four stands. Larger stocktypes and gap sizes improved seedling height, diameter, and growth; ANOVA indicated only gap size was significant for seedling survival. Logistic regression showed survival was positively correlated to diameter at year 1, and aspect, gap size, and stocktype were significant predictors of survival. Our data indicated no differences in density of natural regeneration among gap sizes, although trends suggest greater numbers of bigger competitors in larger gaps sizes. Yellow-poplar regeneration was the tallest competitor of more than 50% of all northern red oak seedlings. Competitive status of seedlings after 5 years differed only by stocktype, with large container stock in a better competitive position than bareroot stock. However, less than 20% of seedlings in all stocktypes in each gap treatment were considered competitive (i.e., ≥80% of the height of tallest competitor) against their tallest competitor. The use of larger planting stock may offer greater opportunities for successfully regenerating northern red oak seedlings on productive sites but likely would have to be accompanied by treatments to reduce woody competition.

Growth of Longleaf and Loblolly Pine Planted on South Carolina Sandhill Sites

Abstract Performance of longleaf (Pinus palustris Mill.) and loblolly pine (P. taeda L.) were compared 15–19 years after outplanting on 10 different sites in the sandhills of South Carolina. The study was established from 1988 to 1992 with bareroot seedlings artificially inoculated with Pisolithus tinctorius (Pt) or naturally inoculated with mycorrhizae in the nursery. A containerized longleaf pine treatment with and without Pt inoculation was added to two sites in 1992. Effects of the Pt nursery treatment were mixed, with a decrease in survival of bareroot longleaf pine on two sites and an increase in survival on another site. The containerized longleaf pine treatment substantially increased survival, which led to greater volume compared with bareroot longleaf pine. Loblolly pine yielded more volume than longleaf pine on all sites but one, where survival was negatively affected by fire. Depth of sandy surface horizon affected mean annual height growth of both loblolly and longleaf pine. Height growth per year decreased with an increase in sand depth for both species. Multiple regression analysis of volume growth (ft3/ac per year) for both species indicated a strong relationship to depth of sandy soil and survival. After 15–19 years, loblolly pine has been more productive than longleaf pine, although longleaf pine productivity may be equal to or greater than that of loblolly pine on the soils with the deepest sandy surface layers over longer rotations.

Effects of granivorous rodents on direct seeding of oak and beech in relation to site preparation and sowing date

Planting bare-rooted seedlings is a rather expensive method to regenerate oak ( Quercus robur) and beech ( Fagus sylvatica). Direct seeding could reduce artificial regeneration costs substantially, but the method currently suffers from a number of problems, one of which is seed consumption by rodents. In the present study clear-cut areas in southern Sweden were prepared using one of four different mechanical site preparation methods – disc trenching, patch scarification, topsoil removal or mounding – then manually sown with acorns and beech nuts. Acorns were sown in May and July 2006, and both acorns and beech nuts were sown in May 2007. Three years following sowing, best seedling establishment from viable acorns, 60–70%, was achieved after sowing in mounds in May, and the subsequent survival reached 90–100%. After the first growing season for beech, both seedling establishment and subsequent survival was lower than for oak, which coincides with a higher number of lost beech nuts at the excavation to investigate the fate of seeds. Granivorous rodents ( Apodemus flavicollis, A. sylvaticus, Mus musculus, and Myodes glareolus) were live-trapped more frequently in the vicinity of slash piles compared to other micro-site features, such as uprooted stumps, snags and stones. In 2006, no connection was found between number of rodents captured and proportion of lost seeds, while in 2007 the two were in good accordance. No clear relationship was found between number of captured rodents, vegetation cover class and mechanical site preparation method. More rodents were captured in 2007 than in 2006, and there was an increase in captures from spring until late summer/autumn for both years, which was mirrored in the seedling establishment result from the three different times of sowing. Based on experiences from the present study the recommendation for successful direct seeding of oak on clear-cuts is a combination of mounding site preparation, removal of slash and sowing in May rather than July. However, the results indicate that successful direct seeding of beech is more difficult to achieve.

Effects of Seedling Type on the Establishment, Growth and Precocity of Eastern Black Walnuts (Juglans nigra L.) for Nut Production§

Eastern black walnut (Juglans nigra L.) has potential for agroforestry practices in the eastern United States because of its value for nuts and timber; however, practices for optimum nut production are poorly defined. Studies were conducted to determine the type of planting material that can assure successful establishment of black walnut for nut production. The first study compared the survival and growth of bare root and container seedlings. Survival exceeded 95% with both stock types four years after planting. Bare root seedlings grew less during the first year after planting compared to container stock. No differences in annual growth increment were observed in the next three years. A study was conducted to compare flower production by commercially available open-pollinated seedlings derived from cultivars versus grafted cultivars at three locations in Arkansas and Tennessee. Seventy-two to 87% of the grafted cultivars flowered during the first four years compared to a maximum of 30% for the open-pollinated seedlings by the fourth year. A third study verified a previously reported relationship between trunk diameter and nut yields for grafted cultivars. These results suggest that landowners seeking to establish black walnut plantings for nut production should consider using container stock of grafted cultivars selected for improved nut quality.

Genetic variation in Pinus brutia Ten. seed stands and seed orchards for growth, stem form and crown characteristics

In this study, some adaptive traits (growth, stem, branching and crown characteristics) in a seven-year old plantation of Turkish red pine (Pinus brutia Ten.) were studied in 2008. The experiment was established by using 1+0 bare-root seedlings from 5 seed stands and 5 seed orchards from the same origins in 2001. Randomized block design with three replications was used in the field. There were a total of 100 families, 10 from each of these 10 populations were used in the experiment. Each family was represented with 10 seedlings in each replication. Populations and families within each population were significantly different for all traits both in the seed stands and in the seed orchards. The percent of genetic variation caused by population was considerable except for branch length ranging from 0.19 to 18.28% especially in the seed stands. Variance components due to families in the seed orchards were in general higher than those in the seed stands. Individual heritabilities varied in 0.45 – 0.90 range. Family heritabilities ranged from 0.76 to 0.88. These results indicated that combined population, family and within family selection for studied traits would result in considerable gain in this species. Key words: Genetic variation, heritability, Pinus brutia Ten., seed stand, seed orchard.

USE OF PLANT WATER POTENTIAL FOR SCHEDULING IRRIGATION OF ANATOLIAN BLACK PINE (Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe) SEEDLINGS

The aim of this study was to set up an irrigation scheduling for bare-root Anatolian black pine seedlings growing in the Egirdir Forest Nursery using plant water potential as an indicator of plant water stress. For this purpose, predawn, midday and daily plant water potentials were measured periodically with plant pressure chamber from mid April till mid November in second growing season of Anatolian black pine seedlings. According to the results, irrigations in the nursery should start in mid April and continue until early June and should be applied when predawn water potential drops below -0.5 MPa. After this period in the phase of bud dormancy initiation (early June till early September), to stimulate root growth and extension only when predawn water potential drops -0.8 MPa, seedlings should be adjusted to bring the top 20 cm of the soil to field capacity. In the last period (early September-mid November) watering should commence when predawn water potential drops below -1.3 MPa. Plant water potential should not be allowed to fall below -1.3 MPa during the day. Keyword: Anatolian black pine, predawn water potential, irrigation scheduling

Effect of midstory and understory removal on the establishment and development of natural and artificial pin oak advance reproduction in bottomland forests

Regenerating oaks (Quercus L.) on mesic and hydric sites has remained a problem largely because of inadequate density and poor distribution of large oak advance reproduction prior to harvesting. We examined the effect of midstory and understory removal on the establishment and 3-year development of natural and artificial sources of pin oak (Q. palustris Muenchh.) advance reproduction in bottomland forests in southeastern Missouri, USA. Midstory and understory removals increased the photosynthetically-active radiation (PAR) reaching the seedling layer from about 3 to 15%. This increased light did not increase the density of natural pin oak advance reproduction compared to control, but it increased the survival and nominally increased the growth of the natural pin oak advance reproduction. Where the midstory and understory had been removed, underplanted RPM® container stock and bareroot pin oak stock maintained high survival, but of the two only the RPM® stock maintained positive height and diameter growth while bareroot stock suffered some growth reductions. Pin oaks originating from the direct seeding of stratified acorns sown in the spring had low germination and survival, but the survivors had growth rates similar to those of natural seedlings in thinned stands. Applying triclopyr to competitors in the ground flora layer only nominally increased PAR but reduced the percent survival and marginally increased the growth of natural and artificial pin oak. We conclude that artificial reproduction may be used to further increase the probability of achieving adequate numbers of the desired species in the future. Bareroot seedlings may not perform as well as RPM® seedlings and natural seedlings already present. However, bareroot and RPM® seedlings remained significantly larger than the natural seedlings after 3 years.

Stock Type, Subsoiling, and Density Impact Productivity and Land Value of a Droughty Site

Abstract Management practices that overcome low seedling survival and poor tree growth of well-drained, droughty sites can improve their productivity and profitability. This study was established to explore tree and stand growth trends, potential forest product yields, and land expectation values of loblolly pine on a droughty site in response to (1) seedling stock type, (2) subsoiling, and (3) stand density regime. In winter 1993, container (CONT) and bareroot (BARE) seedlings were planted with or without subsoiling at 746 trees per hectare (TPH). BARE seedlings were planted without subsoiling at 1,493 TPH to provide a comparison between low-density treatment combinations and a conventional (CONV) management regime for this site type. Tree growth was monitored periodically through age 13 years. Yield trajectories were estimated by predicting forest product yields with FASTLOB using age 13 years stand characteristics, and land expectation value was determined from revenue predictions and costs associated with each treatment. Low-density regimes that included CONT seedlings or subsoiling before BARE seedling planting improved tree growth through midrotation and had yield estimates comparable with that of a CONV regime. However, land expectation values associated with subsoiling were lower than those of low-density CONT and CONV regimes because of its cost and negligible benefits for seedling survival.

Evaluation of Tree Seedling Mortality and Protective Strategies in Riparian Forest Restoration

Abstract Riparian forest restoration can be severely constrained by tree seedling mortality. I evaluated the effects of tree shelters and planting density on herbivory and seedling mortality at a restoration site in the Lake Champlain Basin of Vermont. Eighteen experimental units were established along a 5th-order stream and planted with bare-root seedlings of seven species associated with northern hardwood floodplain forests. Two treatments were applied in a factorial design: shelters versus no shelters and high versus low planting density. Mortality and herbivory data were collected over three growing seasons. Survivorship declined to 56.4% after three growing seasons and varied significantly by species. Planting density, presence/absence of shelters, and their interaction had significant effects on survival, browse, or girdling intensity when tested for all species combined. Browse rates were high (44%), whereas girdling rates were low (3.4%). Both browse (P < 0.001) and girdling (P = 0.022) contributed to seedling mortality. High rates of deer browse on seedlings in shelters were due, in part, to the short height (60 cm) of the shelters, suggesting a need for taller shelters. A large portion (39%) of dead seedlings were neither browsed nor girdled, signaling the importance of other mortality agents. An adaptive approach is recommended to compensate for high seedling mortality and the limited effectiveness of protective devices.

A Stand-Development Approach to Oak Afforestation in the Lower Mississippi Alluvial Valley

Abstract Oak (Quercus spp.) afforestation in the Lower Mississippi Alluvial Valley has involved planting 1-year-old bareroot seedlings on a relatively wide spacing in single-species stands or planting light-seeded species with oaks to form mixed-species stands. In the former case, the developing single-species stands have limited future management options because they do not provide structures that favor quality wildlife habitat or quality sawtimber production. In the latter case, species mixtures are being planted with little knowledge of subsequent stand development, leading to an inability to predict future stand composition for management purposes. In this article, we present a system to determine bottomland tree planting mixtures that will create single-cohort, mixed-species stands with a component of high-quality bottomland oak. Using individual species ecological life-history characteristics, such as early height growth pattern, relative twig diameter and durability, and developmental patterns in natural stands, bottomland species are rated for their ability to provide beneficial training effects that will lead to the development of quality oak boles. Incorporating such a system to determine species value in mixtures should provide an increased number of future options to meet explicit management objectives and promote improved restoration of bottomland hardwood ecosystems.

Effect of planting stocktype and cultivation treatment on the establishment of Norway spruce on cutaway peatlands

In order to determine the effect of stocktype and cultivation treatment on the field performance (survival and growth) and physiological status of Picea abies in cutaway peatlands, small bare-root, large bare-root and containerised seedlings were planted in a deep ploughed and a control site. Survival after 2 years was good across all treatment (>90%) except for the large bare-root seedlings growing in the control site (84%). For all the morphological characteristics assessed in this study, there was no significant interaction between stocktype and cultivation treatment indicating that the growth response to site cultivation was not stocktype dependent. After two growing seasons, all Norway spruce seedlings performed better in the deep ploughed site and displayed also better nutritional and physiological status. Regardless of cultivation treatment, mean height, diameter and volume increment were significantly smaller for the large bare-root seedlings while the small bare-root seedlings displayed the greatest growth rates. In order to promote early height growth in container and small bare-root stock, large diameter is important. Other initial characteristics such as foliar nitrogen content may also have a strong influence on first year field performance. The physiological status of the seedlings during the first year after outplanting was assessed using chlorophyll fluorescence (CF) measurements. CF measurements detected a higher level of stress for the large-bare root stock (low Fv/Fm). On the other hand, small bare-root stock displayed highest maximum potential photochemical activity which corresponded to greatest growth rates. Container seedlings demonstrated higher capacity for photosynthetic electron transport during the first five months after planting suggesting that they recovered from planting stress quicker and optimised better light interception and utilization than bare-root stock. It can be concluded that intensive management systems including deployment of best-adapted stocktype and site cultivation can be used to enhance early height growth of Norway spruce on cutaway peatlands.

Evaluation of transplanted bare-rooted cocoa seedlings for enhanced field establishment under different preservation methods

Different preservation techniques were tried to determine the most suitable method of keeping bare-rooted cocoa seedlings prior transplanting. Preservation days before transplanting were determined. There were significant differences (P

Relação entre produção de beterraba, Beta vulgaris var. conditiva, e diferentes métodos de plantio

Beet root planting methods and the most appropriated type of trays for the production of beet-root seedlings, Beta vulgaris var. conditiva (Chenopodiaceae) are analyzed. Experiment evaluated characteristics of seedling growth and production. Treatments consisted of direct sowing, bare-root seedlings and seedlings grown on 128, 200 and 288-cell trays. Cells with the smallest substratum volumes showed an inferior performance in number of leaves and dry matter weight of the seedlings' aerial part. However, no effect of the substratum volume was reported in the root development. When all treatments were harvested at the same date, direct sowing resulted in larger total and commercial production. However, when the cycle was prolonged until the plants of each treatment had reached the established harvesting point, differences between the treatments of commercial production no longer existed

Fifteen-year response of weed control intensity and seedling type on Norway spruce survival and growth on arable land

The effects of seedling type (2-year-old container seedlings vs. 4-year-old bare-rooted seedlings) and post-planting vegetation control intensity on the growth and survival of Norway spruce (Picea abies (L.) Karst.) seedlings were compared based on 15-year data from a field experiment established on arable land. Vegetation control treatments with terbuthylazine and glyphosate were carried out 1–3 times on successive years, either as overall or spot applications. The highest stand volumes were obtained with the combination of large bare-rooted seedlings and effective vegetation control. Volume of bare-rooted seedlings was greater than that of container seedlings in all treatments (e.g. on the control plots 9.5 m/ha vs. 4.1 m/ha). The best results were obtained with the most intensive weed control treatments (spot treatment repeated twice and overall application repeated three times). These treatments increased both bare-rooted and containerised seedlings’ survival by 33–40% units and their height, breast height diameter, and volume by 45–49%, 17–47%, and 249–279%, respectively. In terms of survival, the container seedlings, in due part to their smaller size, benefited from vegetation control more than the bare-rooted seedlings. Successive early summer frosts damaged the seedlings and significantly retarded their growth. The frequency of frost damage was not affected by vegetation control nor was it attributed to seedling type.33

Physiological characteristics of tropical rain forest tree species: A basis for the development of silvicultural technology

The physiological characteristics of the dominant tree species in the tropical rain forest mainly belonging to dipterocarps as well as the environmental conditions especially for the light in the forest were studied to establish the silvicultural system for the forest regeneration in the tropical South Asia. The flowering patterns of the dipterocarp trees are usually irregular and unpredictable, which make difficult to collect sufficient seeds for raising the seedlings. The field survey revealed the diverged features of the so-called gregarious or simultaneous flowering of various species of this group. Appropriate conditions and methods for the storage of the seeds were established according to the detailed analyses of the morphological and physiological characteristics of the seeds such as the low temperature tolerance and the moisture contents. The intensity and spectra of the light in the forest primarily determine the growth and the morphological development of the seedlings under the canopy. Based on the measurements of the diffused light at the sites in the tropical forest in the varying sunlight, the parameters such as “the steady state of the diffuse light” and “the turning point” were defined, which were useful to evaluate the light conditions in the forest. To improve the survival of the transplanted seedlings, a planting method of “the bare-root seedlings”, the seedlings easy to be handled by removal of all leaves, soil and pots, was developed. Its marked efficiency was proved with various dipterocarps and other tropical trees by the field trial in the practical scale. Tolerance of the various species to the extreme environmental conditions such as fires, acid soils and drought were examined by the experiments and the field survey, which revealed marked adaptability of Shorea roxburghii as a potential species for regeneration of the tropical forests.

Caratterizzazione morfologica di differenti tipi di postime di Juglans regia L. destinati a piantagioni di arboricoltura da legno

Abstract: Good results in plantations are strictly related to the fitness of the nursery stock. Plant fitness, or quality, depends on inherent genetic characters and on physiological and physical (dimensional, morphological and nutritional) characteristics. In arboriculture for wood production the role of stock quality is essential for a prompt expression of plant growth potential. So the necessity to define stock quality standards is widely recognized, though is still discussed how to assess stock cultural value by characteristics easy to measure. First step in such activities is to individuate in the above-ground part of the plantlets some traits related to the root system development. The study was carried out in two public forest nurseries (property of Regione Piemonte) on 163 Juglans regia seedlings and transplants produced for wood plantations. In order to evaluate Walnut nursery stock production, different kinds of bare-root seedlings and transplants have been compared. For each kind, shoot and root system dimensional and morphological traits have been investigated after assignment of plants in 3 dimensional (height) categories. Relations between shoots and roots traits have been studied to allow a visual evaluation of nursery plants based on data easy to collect. This study is to be considered a preliminary survey in the evaluation of stock quality based on field performance.

Root characteristics and growth potential of container and bare-root seedlings of red oak (Quercus rubra L.) in Ontario, Canada

Root characteristics and field performance of container and bare-root seedlings of red oak (Quercus rubra L.) were compared during the first growing season after planting. Sixty seedlings of each stock type were planted on a clearfell and weed-free site near Restoule, Ontario. Twenty-four additional seedlings from each stock type were compared at the start of the study in terms of shoot and root parameters. Measurement of root and shoot parameters were repeated at three dates during the first growing season in the field. The root systems of container stock had a larger number of first order lateral long roots and were significantly more fibrous than bare-root stock. These differences were sustained throughout the first growing season. In terms of field performance, container seedlings had 100% survival and achieved significant increases in both biomass and shoot extension. Bare-root seedlings suffered 25% mortality, significant shoot dieback and more variable growth. The mean relative growth rate (RGR) of container seedlings increased throughout the study period to a maximum of 30 mg/g/day, whereas the mean RGR of bare-root stock remained close to or below zero. Overall, the container seedlings proved less prone to transplanting shock than the bare-root seedlings, most likely due to favourable root architecture and the pattern of root development. Further work may be warranted in container design, growing regimes and root architecture to fully realise the potential of container systems for the production of high quality red oak seedlings across a range of site conditions.

Antelope bitterbrush reestablishment: A Case Study of Plant Size and Browse Protection Effects

After an intense stand-replacement fire in south-central Oregon, 1-y-old (1+0) bareroot seedlings of antelope bitterbrush (Purshia tridentata (Pursh) DC. [Rosaceae]) were outplanted over a 4-y period. Paired-plots were established to examine the benefits of protecting the plants from damage due to animal browsing with Vexar® mesh tubing. In the first growing season, height growth in the protected plots was 18.4 cm (7.4 in) compared with 15.6 cm (6.3 in) in the unprotected plots. Survival was also higher in the protected plots (70% as compared with 62%). Larger plants had greater survival than smaller plants. Survival after the first growing season was well correlated with survival up to 3 y later (r = 0.59, P = 0.01). Use of browse protection will increase survival and growth, but one must weigh the added costs against the alternative of planting more shrubs initially.

Influence of seasonal planting date on field performance of six temperate deciduous forest tree species

Most afforestation hardwood plantations in the Central Hardwood Forest Region, USA, are established with bareroot seedlings planted in late winter or early spring. This brief planting season is preferred for several logistical and physiological reasons, yet interest in fall planting has increased as a means to extend the planting season. We evaluated effects of a wide range of planting dates on 2-year survival and growth for six different temperate deciduous forest tree species grown as 1 + 0 bareroot stock at a southern Indiana, USA, nursery and outplanted onto an afforestation site in southeastern Indiana. In 2001–2002 and again in 2002–2003, seedlings were planted on 10 and 9 different planting dates, respectively, between November and July. Planting date only affected survival of Prunus serotina Ehrh. and Juglans nigra L. in 2001–2002, and Liriodendron tulipifera L. in 2002–2003. Planting date did not consistently affect seedling growth of any species; however, low precipitation in summer of 2002 apparently limited growth of late season plantings. These results suggest that the planting season could effectively be extended given adequate soil moisture.

Comparison of planting stock for establishing black walnut in central Kansas

Abstract Reliability and cost of different types of planting stock under various climatic and site conditions are important. We tested three types of planting stock for survival and growth: bare-root seedlings, nuts, and container stock of black walnut. In this study, in which we had good soil fertility, weed control, and moisture, we found no difference in the success between the three types of plantings. If seed predation problems may exist, using bare-root, dormant seedlings in the spring for establishing typical forestry plantings is encouraged; otherwise seeds may be used if in an open field site.