Characterizing the Utility of the Root-to-Shoot Ratio in Douglas-Fir Seedling Production

Nursery-grown tree seedlings are a vital component of successful restoration and reforestation programs, useful when calls for increased planting for industrial forest management are made, and a tool for climate change mitigation. One of the most extensively planted and studied trees in Western North America is Douglas-fir. Building on that body of work, this review was conducted to identify if the root-to-shoot ratio (root:shoot, R:S), a commonly referred-to metric in reforestation planning, yields meaningful guidance for producing seedlings that are better able to establish across a variety of field conditions. The results indicated that there is wide variability in R:S of nursery-grown seedlings. The relationship between R:S and subsequent root growth and seedling survival varies depending on Douglas-fir variety, seedling stocktypes, and site conditions. The biological and physiological basis for using R:S remains, and likely could be used to enhance seedling quality; however, there is an ongoing need for planning and collaboration between researchers and practitioners to identify how to best deploy this evaluation tool.

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Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings

Plant Disease ◽

10.1094/pdis-09-12-0895-re ◽

2013 ◽

Vol 97 (6) ◽

pp. 744-748 ◽

Cited By ~ 23

Author(s):

Jerry E. Weiland ◽

Bryan R. Beck ◽

Anne Davis

Keyword(s):

Pseudotsuga Menziesii ◽

Seedling Survival ◽

The United States ◽

Douglas Fir ◽

Tree Seedlings ◽

Pythium Species ◽

Forest Nursery ◽

Damping Off ◽

Greenhouse Study ◽

Forest Nurseries

Pythium species are common soilborne oomycetes that occur in forest nursery soils throughout the United States. Numerous species have been described from nursery soils. However, with the exception of P. aphanidermatum, P. irregulare, P. sylvaticum, and P. ultimum, little is known about the potential for other Pythium species found in nursery soils to cause damping-off of tree seedlings. A greenhouse study was conducted to evaluate the pathogenicity and virulence of 44 Pythium isolates representing 16 species that were originally recovered from soil at three forest nurseries in Washington and Oregon. Seeds of Douglas-fir (Pseudotsuga menziesii) were planted into soil infested with each of the isolates. Seedling survival, the number of surviving seedlings with necrotic root lesions, and taproot length were evaluated 4 weeks later. Responses of Douglas-fir to inoculation varied significantly depending on Pythium species and isolate. Eight species (P. dissotocum, P. irregulare, P. aff. macrosporum, P. mamillatum, P. aff. oopapillum, P. rostratifingens, P. sylvaticum, and P. ultimum var. ultimum) significantly reduced the number of surviving seedlings compared to the noninoculated treatment. However, all Pythium species caused a greater percentage of seedlings to develop root lesions (total mean 40%) than was observed from noninoculated seedlings (17%). Taproot length varied little among Pythium treatments and was not a useful character for evaluating pathogenicity. Results confirm the ability of P. irregulare, P. mamillatum, and P. ultimum var. ultimum to cause damping-off of Douglas-fir seedlings, and are indicative that other species such as P. dissotocum, P. aff. macrosporum, P. aff. oopapillum, P. rostratifingens, and P. sylvaticum may also be responsible for seedling loss.

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Influence of Atomization Nozzles and Spraying Intervals on Growth, Biomass Yield, and Nutrient Uptake of Butter-Head Lettuce under Aeroponics System

Agronomy ◽

10.3390/agronomy11010097 ◽

2021 ◽

Vol 11 (1) ◽

pp. 97

Author(s):

Mazhar H. Tunio ◽

Jianmin Gao ◽

Imran A. Lakhiar ◽

Kashif A. Solangi ◽

Waqar A. Qureshi ◽

...

Keyword(s):

Root Growth ◽

Nutrient Uptake ◽

Nutrient Solution ◽

Biomass Yield ◽

Chemical Properties ◽

Cultivated Plants ◽

Growth Ratio ◽

Shoot Ratio ◽

Droplet Sizes ◽

Root To Shoot Ratio

The atomized nutrient solution droplet sizes and spraying intervals can impact the chemical properties of the nutrient solution, biomass yield, root-to-shoot ratio and nutrient uptake of aeroponically cultivated plants. In this study, four different nozzles having droplet sizes N1 = 11.24, N2 = 26.35, N3 = 17.38 and N4 = 4.89 µm were selected and misted at three nutrient solution spraying intervals of 30, 45 and 60 min, with a 5 min spraying time. The measured parameters were power of hydrogen (pH) and electrical conductivity (EC) values of the nutrient solution, shoot and root growth, ratio of roots to shoots (fresh and dry), biomass yield and nutrient uptake. The results indicated that the N1 presented significantly lower changes in chemical properties than those of N2, N3 and N4, resulting in stable lateral root growth and increased biomass yield. Also, the root-to-shoot ratio significantly increased with increasing spraying interval using N1 and N4 nozzles. The N1 nozzle also revealed a significant effect on the phosphorous, potassium and magnesium uptake by the plants misted at proposed nutrient solution spraying intervals. However, the ultrasonic nozzle showed a nonsignificant effect on all measured parameters with respect to spraying intervals. In the last, this research experiment validates the applicability of air-assisted nozzle (N1) misting at a 30-min spraying interval and 5 min of spraying time for the cultivation of butter-head lettuce in aeroponic systems.

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Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

Scientific Reports ◽

10.1038/s41598-021-95752-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tomohiro Fujita

Keyword(s):

Seed Dispersal ◽

Tree Species ◽

Seedling Survival ◽

Fire Suppression ◽

Forest Tree ◽

Tree Seedlings ◽

Seedling Mortality ◽

Forest Tree Species ◽

Seed Deposition ◽

Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

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Bigleaf maple seedling establishment and early growth in Douglas-fir forests

Canadian Journal of Forest Research ◽

10.1139/x88-189 ◽

1988 ◽

Vol 18 (10) ◽

pp. 1226-1233 ◽

Cited By ~ 11

Author(s):

Jeremy S. Fried ◽

John C. Tappeiner II ◽

David E. Hibbs

Keyword(s):

Seed Predation ◽

Seedling Survival ◽

Seedling Emergence ◽

Early Growth ◽

Douglas Fir ◽

Stand Development ◽

Size Distributions ◽

Canopy Density ◽

Successful Establishment ◽

Survival Of Seedlings

Survival, age and height distributions, and stocking of bigleaf maple (Acermacrophyllum Pursh) seedlings were studied in 1- to 250-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in western Oregon to identify the stages in stand development in which bigleaf maple is most likely to establish successfully from seed. Maple seedling emergence averaged 30–40% where seeds were planted and protected from rodents but was typically <2% for unprotected seeds. Seedling survival after 2 years was highly dependent on canopy density, measured by percent sky. Average 1st-year survival of seedlings originating from planted, protected seeds was highest in clearcuts (1–2 years old, 36% survival, 56% sky) and pole-size stands (41–80 years old, 30% survival, 17% sky) with sparse understories and canopies. It was lowest in young stands with dense canopies (20–40 years old, 4% survival, 8% sky) and old stands (81–250 years old, 14% survival, 13% sky) with dense understories. Naturally regenerated populations of bigleaf maple seedlings, which occurred in aggregations (0.005–0.04 ha in area), were most abundant (up to 10 000/ha) in pole-size Douglas-fir stands. Although seedling size distributions within stands had a strongly inverse J shaped form, size distributions within aggregations appeared more normal (bell-shaped). Seedling age rarely exceeded 15 years. Seedlings grew slowly in the understory, often reaching only 25 cm in height after 8–10 years, and were intensively browsed by deer. Naturally regenerated seedlings were virtually absent from clearcuts, probably because of dense competing vegetation and lack of seed caused by poor dispersal and seed predation. The "window" for the most successful establishment of bigleaf maple seedlings appears to begin after canopy thinning and end before forbs and shrubs invade.

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Predicting Swiss Needle Cast Disease Distribution and Severity in Young Douglas-Fir Plantations in Coastal Oregon

Phytopathology ◽

10.1094/phyto.2003.93.7.790 ◽

2003 ◽

Vol 93 (7) ◽

pp. 790-798 ◽

Cited By ~ 32

Author(s):

Pablo H. Rosso ◽

Everett M. Hansen

Keyword(s):

Prediction Model ◽

Disease Severity ◽

Pacific Northwest ◽

Regression Tree ◽

Douglas Fir ◽

Slope Aspect ◽

Disease Prediction ◽

Needle Cast ◽

Swiss Needle Cast ◽

The Relationship

Swiss needle cast (SNC), caused by the fungus Phaeocryptopus gaeumannii, is producing extensive defoliation and growth reduction in Douglas-fir forest plantations along the Pacific Northwest coast. An SNC disease prediction model for the coastal area of Oregon was built by establishing the relationship between the distribution of disease and the environment. A ground-based disease survey (220 plots) was used to study this relationship. Two types of regression approaches, multiple linear regression and regression tree, were used to study the relationship between disease severity and climate, topography, soil, and forest stand characteristics. Fog occurrence, precipitation, temperature, elevation, and slope aspect were the variables that contributed to explain most of the variability in disease severity, as indicated by both the multiple regression (r 2 = 0.57) and regression tree (RMD = 0.27) analyses. The resulting regression model was used to construct a disease prediction map. Findings agree with and formalize our previous understanding of the ecology of SNC: warmer and wetter conditions, provided that summer temperatures are relatively low, appear to increase disease severity. Both regression approaches have characteristics that can be useful in helping to improve our understanding of the ecology of SNC. The prediction model is able to produce a continuous prediction surface, suitable for hypothesis testing and assisting in disease management and research.

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Adjacency to a harvest trail increases drought resistance of interior Douglas-fir (Pseudotsuga menziesii var. glauca) in partially harvested stands in central British Columbia

Canadian Journal of Forest Research ◽

10.1139/cjfr-2018-0007 ◽

2018 ◽

Vol 48 (7) ◽

pp. 809-820 ◽

Cited By ~ 1

Author(s):

Neil P. Thompson ◽

Kathy J. Lewis ◽

Lisa M. Poirier

Keyword(s):

British Columbia ◽

Drought Tolerance ◽

Pseudotsuga Menziesii ◽

Growth Rates ◽

Habitat Management ◽

Odocoileus Hemionus ◽

Douglas Fir ◽

Ring Analysis ◽

The Relationship

Drought tolerance of trees may be affected by competition, but most studies quantifying the relationship do not consider the effect of stem clustering. Trees are often clustered in interior Douglas-fir (Pseudotsuga menziesii var. glauca (Mayr) Franco) forests near the grassland interface in central British Columbia due to past harvesting practices or habitat management for mule deer (Odocoileus hemionus hemionus (Rafinesque, 1817)). Climate change projections indicate continued increases in temperature, an outcome that would stress trees growing in dry environments. Trees placed in different states of competition by mechanical harvesting in the 1970s were sampled to provide a 40-year comparison of three levels of competition during 1–2 year droughts. Tree-ring analysis was used to assess the reduction in growth during drought years and resumption of growth in subsequent years. A clear separation of growth rates was evident between open-growing trees, trees on the edge of harvesting trails, and trees within the unharvested interior. Edge trees had intermediate growth rates but no differences were found in the long-term climate–growth relationship compared with open-growing trees. Both Edge and Open classes showed less relative growth reduction during droughts than Interior trees growing between harvest trails. Precipitation throughfall rates and competition for resources are likely driving short-term drought tolerance in combination with other factors.

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Prevalence of Violence Estimation in Russia through a Retrospective Youth Survey

Social Psychology and Society ◽

10.17759/sps.2021120210 ◽

2021 ◽

Vol 12 (2) ◽

pp. 166-182

Author(s):

E.N. Volkova ◽

I.V. Volkova ◽

O.M. Isaeva

Keyword(s):

Child Abuse ◽

Child Protection ◽

Public Perceptions ◽

Measuring Instruments ◽

Youth Survey ◽

Wide Variability ◽

The Russian Federation ◽

Forms Of Violence ◽

The Relationship

Objective. Estimating the prevalence of violence among children born in Russia in the 1980s, in the early 1990s and in the late 1990s using a retrospective youth survey. Background. Assessing the prevalence of a child abuse is an unresolved scientific and methodological problem. There are disagreements in approaches to assess the prevalence of violence, in interpreting the results. However, the main problem is the problem of reliable measuring instruments. Many studies show a wide variability in estimating prevalence and even in compared parameters; even greater discrepancies arise when it comes to identifying the factors and consequences of child abuse. Such a wide variability of estimation is associated with the insufficient quality of the measuring instruments and research procedures themselves. Study design. The sampling analyzed data on the prevalence of violence among “post-Soviet children”, “children of the 90s” and “children of the 21st century”. The presence and nature of the relationship was checked using methods of mathematical statistics (correlation analysis and analysis of the significance of differences). Participants. The study sample consisted of 537 people aged 18 to 24 years (M=20.23, SD=1.84) living in the Russian Federation. The 2006 sample of respondents included 144 people (25,7% of boys, 74,3% of girls), 2012 — 203 people (36,4% of boys, 63,6% of girls), 2018 — 190 people (35,7% of boys, 64,3% of girls). Measurements. International Questionnaire ICAST-R (ICAST-Retrospective) (adapted by E.N. Volkova, O.M. Isaeva). Results. A comparative analysis of the prevalence of violence among “children of the 21st cen¬tury”, “post-Soviet children” and “children of the 90s” showed that there is more similarity between these groups than differences in the severity of types, forms of violence and their frequency of occurrence (with the exception of cases of sexual violence, the percentage of cases of which is significantly reduced from the 2006 study to the 2018th year). Conclusions. A retrospective survey of young people using ICAST-R allows you to assess the prevalence of violence among children, as well as the state of the child protection system from violence and the content of public perceptions regarding child abuse.

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Breathing and orientation underwater in swimming pool: Effects of age, practice, and duration of an aquatic stimulation program in babies and infants

Brazilian Journal of Motor Behavior ◽

10.20338/bjmb.v2i1.13 ◽

2007 ◽

Vol 2 (1) ◽

pp. 11-21

Author(s):

Eduarda Veloso ◽

João Barreiros ◽

Carlos Santos

Keyword(s):

Aquatic Environment ◽

Motor Behavior ◽

Theoretical Framework ◽

Two Dimensions ◽

Swimming Pool ◽

Chronological Age ◽

Strongly Correlated ◽

Evaluation Tool ◽

Breathing Control ◽

The Relationship

Nowadays there are not many investigation results about infant and baby's motor behavior in the aquatic environment. The present study seeks to describe it before the 40 months of age and to examine the relationship between the motor acquisitions and the chronological age, time of practice and program duration. A system of categories and sub-categories of baby's motor behavior was developed for two dimensions: breathing control and underwater orientation. This system was validated with obtained values of 96% of objectivity and 100% of consistency. Then, 101 babies and infants were evaluated between 3 and 40 months of age, some of them in different moments, in a total of 216 observations (N=216). Breathing control and underwater orientation skills were strongly correlated with chronological age, time of practice and program duration. All the correlations were positive with 0.75-0.86% and significant (Ïâ‰-0.01), meaning that as age, time of practice or program duration increases, the breathing control and underwater orientation skills showed clear improvement. Chronological ages for developmental steps in aquatic environment were identified. Results are discussed within a maturation-stimulation theoretical framework. The evaluation tool that was proposed and validated is ready for use and can be applied in other research settings.

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Assessment of Biomass Expansion Factor (BEF) and Root-to-shoot Ratio (R) for some Tree Species of Uttarakhand, India

Indian Journal of Forestry ◽

10.54207/bsmps1000-2014-4x81zi ◽

2014 ◽

Vol 37 (4) ◽

pp. 371-377

Author(s):

Laxmi Rawat ◽

Pramod Kumar ◽

Nishita Giri

Keyword(s):

Tree Species ◽

Tectona Grandis ◽

Expansion Factor ◽

Pinus Roxburghii ◽

Biomass Expansion Factor ◽

Shorea Robusta ◽

Shoot Ratio ◽

Harvesting Method ◽

Root To Shoot Ratio ◽

Age Series

The present study was conducted in Shorea robusta (sal), Pinus roxburghii (Chir pine), Tectona grandis (Teak) and Ailanthus excelsa (Ardu) plantations of different ages at different sites in Uttarakhand. Biomass was calculated on the basis of complete tree harvesting method (stratified mean tree technique method). Biomass Expansion Factor (BEF) and root-to-shoot ratio (R) of all these 4 tree species have been calculated and presented in this paper. Sample trees of S. robusta were of 45, 53 and 60 years of age. BEF for all these 3 age series were assessed as 1.3 at 45 years, 1.4 at 53 years and 1.2 at 60 years of age. Similarly, R values were assessed as 0.27, 0.28 and 0.26, respectively, in these 3 age series. BEF and R values assessed for T. grandis (28 years age) as 1.46 and 0.21; and for A. excelsa (39 years age) as 1.23 and 0.23, respectively. BEF for P. roxburghii trees calculated as 2.3 for 13 years age, 1.75 for 20 years, 1.71 for 22 years, 1.5 for 33 years and 1.46 for trees of 45 years of age. Similarly, R values were 0.2 for 13 years, 0.21 for 20 years, 0.12 for 22 years, 0.13 for 33 years and 0.15 for 45 years of age. P. roxburghii sample trees have shown decreasing order of BEF with increasing age, whereas S. robusta has not shown such trend along the chronosequence.

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Built environment and autism: towards a set of spatial requirements for autism friendly cities

European Journal of Public Health ◽

10.1093/eurpub/ckaa165.1393 ◽

2020 ◽

Vol 30 (Supplement_5) ◽

Author(s):

G Tola ◽

V Talu ◽

J Lindert

Keyword(s):

Built Environment ◽

Urban Environment ◽

Functional Organization ◽

Spatial Configuration ◽

Autism Spectrum ◽

Urban Environments ◽

Urban Planning And Design ◽

Wide Variability ◽

The Relationship ◽

Spatial Needs

Abstract Background The opportunity for people functioning in an atypical way to autonomously and fully interact with the city is often compromised or denied, due to the gap between their specific spatial needs and the physical and functional organization of the urban environment. The need to reconsider the living environments taking into account the vast diversity of people gained an increasing importance in the overall debate and specifically in the field of urban planning and design. The research aims at investigating the relationship between the urban environment and people with Autism Spectrum Disorder (ASD). Methods A scoping review of current available original studies research exploring the relationship between autism and built environment was conducted. PubMed, Scopus, PsychInfo and Web Of Science where searched. Studies included provided spatial requirements for designing autism friendly environment. Results In total, 801 studies were identified and 22 were included. Current researches and applications investigating the role of spatial configuration as a means for improving the autonomy of people with ASD almost exclusively focus on closed and dedicated spaces (residences, schools, care facilities, healing gardens) mostly devoted to children. Starting from this and the data collected, a first set of enabling urban spatial requirements addressing the atypical urban functioning of people with ASD - the reduction of sensory overload and the use of visual supports - in order to promote their possibility to walk autonomously and safely across the everyday city is proposed. Conclusions Despite the wide variability of the spectrum which makes it very difficult to define effective design criteria for all people with ASD, it's possible to identify a set of recurrent spatial needs. Furthermore, designing cities for people with ASD can also contribute to healthier and more inclusive urban environments for other groups of vulnerable inhabitants.

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