Research

The Ohio Chapter’s research committee is responsible for locating and disseminating research findings that affect Ohio tree care professionals. Research documents are separated into primary areas of interest and include a searchable summary provided by the committee. Use the search feature in the lower right corner to search using a keyword.

If you have research papers you think would be of interest to Ohio professionals or if you cannot locate a certain subject matter, email the Ohio Chapter research committee at info@OhioChapterISA.org.

Other resources:
* Arboriculture & Urban Forestry Online
* TreeFund.org

Climbing

Environmental

The Influence of Soil Decompaction & Amendments on Soil Quality
The research focuses on the impact of soil compaction on urban trees and evaluates different decompaction methods, including air spading, vertical mulching, biochar application, and woodchip mulching. Over 5 years, the study assessed the individual and combined effects of these techniques on soil quality, considering factors such as bulk density, organic matter,
vegetation ground cover, root growth, and earthworm counts.

The Surprising Benefits of Biodiversity
These results are consistent with the biodiversity hypothesis: exposure to biodiversity was associated with a lower risk of developing an immune disease such as childhood Leukemia and Asthma.

Climate Change Atlas
Climate change is already having substantial effects on natural systems and the benefits they provide. Understanding how climate change may intensify through this century is important to prepare for future changes.

Costs of Maintaining and Not Maintaining the Urban Forest
A Review
Over 300 articles were compiled, of which 163 were deemed useful for this review document.

Defence Responses and Resistance Breeding in Forest Tree Species
A Review
Forest trees play an important role not only in mitigating the effects of climate change but also in other considerable economic and ecological value and maintenance of proper ecosystem stability. They are a vital source of alternative bioenergy source and play important roles in pollution abatement and maintenance of biodiversity.

Fluopyram: an Effective Management Tool to combat the Emerging threat to the American Beech, Beech Leaf Disease
Bartlett Research Poster
Fluopyram has proven effective against Lcm in lab assays and some field trial sites. However, high variability in field sites shows that individual trees must be considered in the context of their surroundings. Inoculum pressure in dense beech stands and from overhanging beech canopies may strongly influence treatment efficacy. Current management options should focus on high-value specimens beech, collection preservation, and potentially uncrowded mixed natural stands.

Tree Establishment: A Review of Some of the Factors Affecting Transplant Survival & Establishment
This article reviews some of the factors that induce transplant shock and slow establishment of transplanted nursery stock, such as root and mineral nutrient loss, soil moisture stress, and xylem vessel cavitation, and the methods used to reduce transplant shock.

Heat Tolerance of Urban Trees
There is evidence of genetic variation in heat tolerance between and within urban forestry species, which could be essential to exploit for urban trees. Understanding the mechanisms of tree physiological, biochemical, and molecular responses to extreme heat events is also necessary for understanding how urban tree species will be affected by climate change.

How Effective are Methods to Induce or Facilitate the Natural Resistance of Temperate Trees to Exotic Phytophthora Species?
A Systematic Review
The cost-effectiveness of such interventions requires further research, but this review demonstrates that alternatives to the pruning and felling of diseased trees now exist. This review recommends updated best practices with information on the benefits of the practical application of treatments, including foliar sprays, trunk injections, and soil amendments in treating Phytophthora-based tree diseases.

Impact of Mulches on Landscape Plants and the Environment - A Review
All mulches are not created equally, however, and this review compares the costs and benefits of landscape mulches as reported in the scientific literature. It also presents real and perceived problems associated with various landscape mulches.

Induced Resistance to Pests and Pathogens in Trees
A Review
Tree resistance can be enhanced by a variety of biotic and abiotic inducers, including nonpathogenic and pathogenic microbes and herbivores, resulting in enhanced protection against further biotic injury. Induced resistance could be a valuable tool in sustainable pest management.

Potential of Induced Resistance as a Tool for the Management of Pathogens and Insects in Trees
An Ecological Viewpoint
Under natural conditions, forest ecosystems are usually stable, despite the constant presence of arthropods and pathogens inherently capable fo killing their tree hosts.

A Meta-Analysis of Studies Relating to Organic Materials and Impacts on Soil, Tree, and Environmental Properties
Organic materials are commonly used in urban landscapes to improve soil quality and tree health. Literature reviews suggest that these materials have beneficial effects, but these impacts have yet to be evaluated using a meta-analytical approach. This work presents a literature summary of 176 articles published in Arboriculture & Urban Forestry (AUF) and evaluates 33 of these papers using a meta-analysis.

Threats to the Sustainability of Urban Forests
Article
What compromises the sustainability of urban forests from an entomological standpoint? In this article by Michael J. Raupp, he groups these antagonistic features into six broad categories.

A rapid urban site index for assessing the quality of street tree planting sites. For an urban site index to be valuable for urban forestry and arboriculture, it must be practical and accurate. Considerations include the time and expertise required to use the tool.

An Improved Rapid Urban Site Index study showed that the RUSI can be used to relate urban site conditions and urban tree performance.

Ohio Urban Site Index Site Analyses by ODNR is a tool for conducting a community soil inventory. This document explains the methodology, procedure, sampling, and data use.

The Complex Issue of Urban Trees—Stress Factor Accumulation and Ecological Service Possibilities. This review paper is the first to summarize many aspects of trees' ecological role in urban landscapes while considering their growth conditions.

Threats to the Sustainability of Urban Forests
Technical Paper
By understanding factors that threaten the sustainability of our urban forests, arborists can develop Integrated Pest management (IPm) and Plant Healthcare (PHc) programs to mitigate many of the abiotic and biotic forces plaguing trees in urban ecosystems.

Equipment

Plant Healthcare - Diseases

Plant Healthcare - Endophytes

A Review on Defence Responses & Resistance Breeding in Forest Tree Species Tree resistance can be enhanced by a variety of biotic and abiotic inducers, including nonpathogenic and pathogenic microbes and herbivores, resulting in enhanced protection against further biotic injury

Endophytes & Their Potential for Bio-Control of Tree Diseases
Arborists widely recognise the importance of mycorrhiza and their role in enhancing tree health. However, the role of endophytes, i.e. bacteria and fungi that live within and on a tree without causing any disease symptoms, is greatly underappreciated. This article provides a brief overview highlighting the benefits of endophytes, especially their potential as biocontrol agents.

Endophytes as Biological Agents
One of the primary benefits of endophytes is their ability to produce bioactive compounds that can inhibit or kill pathogens. These compounds can act as natural pesticides, reducing the need for chemical treatments and promoting a more sustainable approach to pest management. For instance, certain endophytic fungi produce alkaloids and other secondary metabolites that deter herbivores and inhibit the growth of harmful fungi and bacteria.

Fungal Endophytes & Their Interaction with Plant Pathogens
The inner space of plants represents an ecological niche where numerous species of fungal endophytes live. These ubiquitous fungi have an effect in the way plants interact with their environment. In some ways,a plant is a plant and its endophytes. It appears that most endophytic assemblages contain mutualistic species that help plants to cope with biotic and abiotic stress situations. Because of this, endophytes may have an important role in adapting plants to some particular environments.

Potential of Induced Resistance as a Tool for the Management of Pathogens and Insects in Trees - An Ecological Viewpoint
A selection of previous work that deals with analyses and theories of plant defence is presented and recent contributions on systemic induced resistance in conifers from the author’s own research program are reviewed.

Plant Healthcare - Fungi

Susceptibility of Garden Trees and Shrubs to Armillaria Root Rot
Technical Paper
Armillaria root rot (ARR) is a serious disease of woody plants caused by several species of Armillaria. Three species were identified in the study. The results provide confidence in the use of host resistance as part of the integrated management of ARR>

Beech Leaf Disease Severity Affects Ectomycorrhizal Colonization and Fungal Taxa Composition
Technical Paper
Beech leaf disease is an emerging threat to temperate forests in North America. Over time, BLD infestation leads to leaf senescence and canopy loss. Tree death, especially in the subcanopy, is common. Because fungi rely on the photosynthate of autotrophic hosts, and because BLD causes canopy loss, likely hindering photosynthesis, the study predicted that trees more severely affected by BLD symptoms would have a lower ECM root colonization.

Bleeding Canker Disease of Silver Maple Trees
Technical Notes
Management of silver maple canker diseases should be based on integrated pest management (IPM) principles. Learn more from this guideline for professionals and homeowners.

Boxwood Blight
University of Kentucky Extension Technical Notes
First reported in the U.S. in 2011, boxwood blight was confirmed in a residential landscape in Central Kentucky during October 2014; it is currently present in 27 states. Since its introduction, this disease has continued to spread with the nursery trade and in landscapes.

Boxwood Blight
Perdue Extension Technical Notes
Boxwood blight is a fungal disease easily transported in the nursery industry and can be moved on infected plants that do not show any symptoms at the time of shipment.

Boxwood - Volutella Blight
Fact Sheet
This disease is causing extensive losses in commercial nurseries that produce boxwood.

The Influence of Chitin-Based Soil Amendments on Pathogen Severity of Apple & Pear Scab Penconazole proved very effective for apple and pear scab control in both container and field studies. The results of this study support these conclusions, with penconazole proving to be a highly effective scab protectant in terms of reduced leaf and fruit apple and pear scab severity and increases in leaf chlorophyll content and fruit yield compared to untreated controls.

Potassium Phosphite
Bartlett Research Technical Report
Potassium phosphite is a soil-applied material that has recently gained attention as a method for improving plant vigor and health. Research and field experience have shown that this improvement of plant health after application of potassium phosphite is related to an increase in resistance against a variety of plant pathogens, as well as increased tolerance of many environmental stress factors, including drought stress.

Plant Healthcare - Insects

Ambrosia Beetles
Technical Report
Ambrosia beetles are a specialized group of bark beetles that differ from other bark beetles by boring through the bark and into the sapwood rather than burrowing just below the bark surface. This technical report explores the damage and management.

Chlorantraniliprole: Reduced-risk Insecticide for Controlling Insect Pests of Woody Ornamentals with Low Hazard to Bees
Scientific Paper
Pesticides used to protect woody ornamentals and turf in urban landscapes need to have efficacy against target pests, low mammalian and avian toxicity, stability of performance across different conditions, and minimal impact on pollinators, natural enemies, earthworms, and other beneficial invertebrates. Chlorantraniliprole meets those criteria, making it an attractive alternative to neonicotinoids, pyrethroids, and older chemistries, especially for use on plants that may attract bees.

Combined application of up to ten pesticides decreases key soil processes
Research Article
This research highlights the complex impacts of pesticides and the need for environmental policy to address the threats posed by pesticides.

Ecology of Herbivorous Arthropods in Urban Landscapes
Empirical evidence does not support a conclusion that herbivorous arthropods uniformly attain the greatest richness or abundance along a gradient of increasing urbanization. Lepidoptera generally do not respond in a simple linear fashion. Fertilization almost always decreases tree resistance to herbivores and has the potential to increase their populations, especially in mites, scales, and adelgids that complete multiple generations on the same plant.

Effects of Fertilization on Insect Resistance of Woody Ornamental Plants: Reassessing an Entrenched Paradigm A critical review of the evidence finds little to support the view widely held within the tree care industry that fertilization enhances insect resistance of woody plants. In fact, substantial evidence demonstrates that fertilization frequently enhances insect performance by increasing the nutritional quality of their hosts and/or by decreasing concentrations of secondary metabolites.

Factors Affecting the Efficacy of Trunk-Injected Emamectin Benzoate to Manage Emerald Ash Borer
Scientific Paper
This study demonstrated that EB can be successfully delivered to the canopy of ash trees by the 3 injection systems.

Observation of External Wounding on Green Ash Trees Associated with Tree Injection Systems
Field observations of external wounds associated with two common tree injection methods compared open (plug-less) and sealed (plug) systems in green ash trees.

Phosphonate fertilizers suppressed root knot nematodes
The nematicidal effect of Calphos and Magphos might be due to their low pH values, their salinity, or the combined effect of both; the pH of the materials containing calcium phosphonate and magnesium phosphonate.

Seasonal & Regional Distributions, Degree-Day Models, & Phoresy Rates of Major Sap Beetle Vectors of the Oak Wilt Fungus
The temperature windows and phoresy rates can be applied across years and regions with similar species compositions. Flight periods of nitidulids can vary markedly between years, so degree-day models can provide generality. Moreover, degree-day models could be useful in predicting the flight periods of these nitidulid vectors of oak wilt under future climate conditions.

Plant Healthcare - Other

Comparison of Apple Planting Methods
Scientific Paper
The tractor-mounted soil auger, a commonly used machine for simplifying the planting of apple trees, was shown to create a compact hole wall that remains evident over time. In a comparison of the auger to a backhoe, a commercial tree planter, a ditch trencher, and an auger modified to fracture the sides of the planting hole, shoot length and anchorage measurements of trees planted by the alternative planting methods surpassed those planted by the conventional auger. Trees planted by backhoe or tree planter were most successfully established.

Diagnosing herbicide damage to trees
Herbicides are an integral part of landscape maintenance; however, over the past few years research labs have recorded an alarming rise in the number of malicious herbicide poisonings of trees.

Changes in Leaf Thickness, Chlorophyll Content & Gas Exchange of a Landscape Tree Treated with Paclobutrazol and Potassium Nitrate
Scientific Paper
The presence of PBZ produced a more compressed arrangement of cells in the leaves. Darker green leaves were observed due to enhanced relative chlorophyll content following PBZ and KNO treatment.

Effect of the Growth Regulator & Fertilization on Defensive Chemistry & Herbivore Resistance of Pine and Paper Birch
Recommended rates of paclobutrazol had powerful growth-regulating effects on paper birch and Austrian pine. Associated physiological effects on paper birch included decreased leaf area, increased specific leaf mass, and dramatically increased production of female catkins. However, decreased growth of Austrian pine was not associated with such substantial effects on leaf morphology. The effects of paclobutrazolon secondary metabolism and insect resistance were species-specific and time-sensitive.

Non-structural carbon compounds in temperate forest trees A comprehensive study of the dynamics of non-structural carbon compounds in leaves and branches as well as stem sapwood in mature trees of 10 different species, growing under the same climatic conditions.

Paclobutrazol-induced Drought Tolerance in Containerized English & Evergreen Oak
PBZ treatment induced a suite of physiological adaptions that would allow both species to tolerate drought, more specifically, increased total leaf content of carotenoids (lutein:-carotene:neoxanthin:-carotene) and xanthophylls (zeaxanthin:antheraxanthin: violaxanthin), chlorophylls, pro-line, superoxide dismutase, and catalase.

Paclobutrazol Boost up for Fruit Production: A Review
Paclobutrazol is a growth inhibitor and also belongs to the triazol group. It inhibits the biosynthesis of GA3 at kaurene stage and it is most commonly used for the induction of flowering in off season, control tree vigour for HDP (canopy managment), increase fruit set and yield, improve fruit quality when applied to the soil.

Influence of Paclobutrazol on temperate fruit crops: A Review
The use of paclobutrazol is increasing day by day in different fruit crops to influence different plant responses. Its use is also picking up in temperate fruit crops. This review covers the influence of paclobutrazol on plant growth, water relations, physiology, and leaf nutrient status in different temperate fruit crops.

Quantitative Tools for Prediction of Pavement Damages Associated with Urban Trees
Scientific Paper
This study aimed to (1) establish allometric relationships between DBH and TFD of common urban tree species, and (2) identify factors affecting the presence and magnitude of protruding roots and flares.

Professional Expertise & Its Role in Risk Assessment
Scientific Paper
Professional judgment is derived from a person's intuition, training, and level of expertise. When exploring the influence that expertise has on the process of tree risk assessment, it is helpful to approach the topic in relation to its impact across various disciplines. This paper reviews the effects of arboricultural and tree risk assessment training on the assessor and overall tree risk assessment methodology through the lens of professional judgment and decision-making. Additionally, the topic of risk perception is explored based on how it can affect decision-making. Concepts and theories related to risk perception are applied to arboriculture and tree risk assessment to provide additional insight into how subjectivity and personal bias may affect recommendations, mitigation, and the overall management of our urban forests. The review finds that an individual’s perception of a risk can be equally as influential as the reality of the risk on the decision-making process.

Threats to the Sustainability of Urban Forests
Technical Paper
By understanding factors that threaten the sustainability of our urban forests, arborists can develop Integrated Pest Management (IPm) and Plant Healthcare (PHc) programs to mitigate many of the abiotic and biotic forces plaguing trees in urban ecosystems.

Costs of Maintaining and Not Maintaining Urban Trees
ISA Review
This ISA Review presents a detailed summary of the corresponding literature on the costs of maintenance and lack of maintenance for types of tree care commonly included in municipal budgets.

Soil fertility management and insect pests: harmonizing solid and plant health in agroecosystems
Soil fertility management can have several effects on plant quality, which in turn can affect insect abundance and subsequent levels of herbivore damage. The reallocation of mineral amendments in crop plans can influence oviposition, growth rates, survival, and reproduction in the insects that use these hosts.

Plant Healthcare - Soils

Airspade: The Root of the Problem
Much attention has been given to how the accessible, above ground tree structures respond to injury, yet little attention has been paid to how the roots of trees individually respond to root pruning.

The Influence of Biochar Soil Amendment on Tree Growth & Soil Quality
This study shows that biochar can enhance tree survival by several mechanisms, mostly related to improved soil function. Even a small increase in tree survival rates could make biochar application cost-effective for use by local authorities or tree caretakers. Future research needs to decipher the impact of biochar on tree tolerance against environmental stresses in the urban environment, with a focus on longer-term studies and the

Biochar & Biosolids Increase Tree Growth & Improve Soil Quality for Urban Landscapes (Scharenbroch, et al 2013)
Significant treatment effects were detected for all tree responses. Effects of soil type and species were also significant, but no interactions between treatment x soil or treatment x species were detected. Total tree biomass was greater with BS compared with ACT and NUL. Total tree biomass was also greater with BC compared with NUL.

Treatment of Biochar, Fertilization, and Tillage Improves Soil Organic Matter and Tree Growth
Scientific Paper
Arborists and urban foresters commonly use tillage, fertilization, and amendment with organic materials to improve soil. Practitioners often combine these actions.

The Role of Biostimulants as Alleviators of Biotic & Abiotic Stresses in Grapevine Alternative holistic approaches, such as those making use of biostimulants, are emerging to reduce the consequences of biotic and abiotic stresses in the grapevine, namely preventing grape fungal diseases, improving grape vine resistance to water stress, and increasing yield and berry quality.

Exploring Management Methods for Beech Leaf Disease, an Emerging Threat to Forests and Landscapers
Soil-injected acephate applications, whether applied in late summer or at bud swell, in trial locations had no effect on the disease severity of the treated trees or on the overwintering nematode population within buds. The tree condition worsened from the 2021 pretreatment to the 2022 post-treatment evaluations for all treatment groups including the non-treated control.

Fish By-Product Use as Biostimulants: An Overview of the Current State of the Art, Including Relevant Legislation and Regulations (2020)
Fish processing waste products have potential applications as plant biostimulants. This review gives an overview of plant biostimulants with a focus on fish protein hydrolysates and legislation governing the use of plant biostimulants in agriculture.

Cation Exchange Capacity (CEC)
Fact Sheet
Soils have a CEC primarily because clay particles and organic matter in the soil tend to be negatively charged. Since the soil as a whole does not have electric charge, the negative charge of the clay particles is balanced by the positive charge of the cations in the soil.

Chemical & Biochemical Properties of Humic Substance from Forest Soils & Plant Growth
Scientific Paper
It is well known that soil humic substances can affect plant growth by behaving as growth hormones. In many systems, humic substances behave similarly to true auxins, but until recently it had not been shown that they could contain substances similar to auxins.

Effect of Compost-amended Backfill & Paved Surface on Leaf Parameters & Physiology of Norway Maple
The results of this study show that the size and type of the unpaved area determine tree health. A larger mulched area with groundcover planting was superior to a smaller paved area.

Compost improves soil properties and tree establishment along highway roadsides.
The study's results demonstrate the inadequacy of survivorship as a sole measure of planting success. The improvements are found to coincide with improved tree establishment, as demonstrated by cumulative tree growth, across the otherwise unfavourable solid conditions characteristic of post-construction, naturalization plant sites.

Fertilization and Soil Microbial Community: A Review
Among the negative effects of chemical fertilization, the decrease in ensymatic activity has been highlighted by several papers, especially in soils that have received the largest amounts of fertilizers together with losses in organic matter.

Organic Matter, Humus, Humate, Humic Acid, Fulvic Acid & Humin: The Importance in Soil Fertility and Plant Health
Scientific Paper
Plants grown on soils that contain adequate humin, humic adds (HAs), and fulvic adds (FAs) are less subject to stress, are healthier, produce higher yields; and the nutritional quality of harvested foods and feeds are superior.

Plant Health & Soil Changes with Humic Substance Applications
Technical Paper
Based on laboratory experiments, humic substances show promise for commercial crop production; however, the extent of positive crop response is difficult to predict. To date, field research has shown mixed results. Humic substances may have an impact on plant growth and soil characteristics; however, the magnitude of the impact is determined by several factors, which include the source of the humic substance, plant species, method of application, and soil type.

Understanding the Role of Humic Acids on Crop Performance and Soil Health
Technical Paper
This review highlights the relevance of HA on crop growth, plant hormone production, nutrient uptake and assimilation, yield, and protein synthesis.

Effect of K-N-Humates on Dry Matter Production and Nutrient Use Efficiency of Maize
Composting and its main attribute, i.e., humic substances, was the focus of this study. The objectives of the study were to (1) produce organic K-and ammonium-based organic fertilizer from composted SW and (2) determine the efficiency of the organic-based fertilizer produced.

Influence of Humic Substances & Nitrogen on Yield, Fruit Quality, & Leaf Mineral Elements
The objective of this research was to study the influence of three levels of ground applications of N and different humic substances on yield, fruit quality attributes (fruit size, color, firmness, soluble solid concentrations, and starch), and leaf mineral concentrations of 'Early Spur Rome' apple trees.

Effect of Soil Application of Humic Acid & Bio-Humic on Yield & Fruit Quality of Olive Trees (El-Razek, etc. al 2020)
The result showed that all treatments improve the nutrient status (N, P, K, Ca, Mg, Fe, Zn, Mn, Cu) of the leaves, yield (kg/tree) and fruit quality, i.e., fruit weight, volume, specific gravity, dimension, and shape index, as wellas fruit moisture content percentage and oil percentage in FW and DW than the control. Within all treatments, the bio-humic treatment (T4) is recommended, since it had the highest value of these parameters in comparison with the other treatments or control.

Fungicidal activities of soil/humic/fulvic acids as related to their chemical structures in greenhouse vegetable fields with cultivation chronosequence
According to research, the active fungicidal components in soil HAs and FAs decreased along with the extension of cultivation years, which made the soil suffer more risk to phytopathogenic fungi. So we believe continuous cultivation too many years in PGVP systems is inadvisable.

Iron and Copper for Citrus Trees Supplying sufficient nutrition should be a high-priority management practice for every grower. An appropriate nutrient balance using fertilizer management is necessary to achieve sufficient plant nutrition for best fruit yield and quality.

Soil Fertility Management & Insect Pests: Harmonizing Soil & Plant Health in Agroecosystems
Scientific Paper
Soil fertility management can have several effects on plant quality, which in turn, can affect insect abundance and subsequent levels of her bivore damage. The reallocation of mineral amendments in crop plants can influence oviposition, growth rates, survival, and reproduction in the insects that use these hosts.

Effect of Leonardite Application on Leaf Nutrient Content & Fruit Chemical Parameters of Cherry
Scientific Paper
Organic fertilizers have an important role in plant nutrition practices by protecting the environment, human health, and ecological balance, and supporting sustainable productivity. Hence, the use of leonardite which has high humic acid content is becoming increasingly common.

Leonardite Influences Zinnia & Marigold Growth
When combined with fertilizer application, zinnia and marigold seedlings and transplants responded favorably to leonardite additions up to 6.25% and then response declined.

Microbial Preparations Combined with Humic Substances Improve the Quality of Tree Planting Material Needed for Reforestation to Increase Carbon Sequestration
The treatment of plants with humic substances increased nitrogen balance indexand chlorophyll content in the leaves of poplar seedlings, which is likely to increase carbonstorage due to increased photosynthesis

Impact of Mulches on Landscape Plants and the Environment
While this literature review focused directly on plant and soil criteria associated with landscape mulches, other important environmental issues may well play a role in the ultimate choice of landscape mulch materials. Such issues as environmental degradation associated with the acquisition of some mulching materials, use of invasive species as ground covers, nutrient overload from overuse of organic mulches, and toxic leachates from some synthetic mulches must also be considered.

Organic Mulch and Grass Competition Influence Tree Rot Development
Tree root densities were generally higher in the mulch and the 0-7.5 cm soil layer below the mulch.

The Potential of Mulch to Transmit Tree Pathogens
Infected needles and shoot tips collected from diseased pines and then used as mulch transmitted S.sapinea to healthy saplings in the field.

Potassium Phosphite
Technical Paper
Potassium phosphite is a soil applied material that has recently gained attention as a method for improving plant vigor and health. Research and field experience have shown that this improvement of plant health after application of potassium phosphite is related to an increase in resistance against a variety of plant pathogens, as well as increased tolerance of many environmental stress factors, including drought stress.

Soil Chemical & Microbiological Properties are Changed by Long-Term Chemical Fertilizers that Limit Ecosystem Functioning
These findings highlight that reduced chemical fertilizers and organic cultivation with beneficial microbiota could be used to improve economic efficiency and benefit the environment in sustainable agriculture

The Influence of Soil Decompaction & Amendments on Soil Quality
Scientific Paper
The research focuses on the impact of soil compaction on urban trees and evaluates different decompaction methods, including air spading, vertical mulching, biochar application, and woodchip mulching. The study underscores the importance of adopting effective long-term soil decompaction measures to improve the survival of urban trees in compacted soils resulting from human activities.

Soil Organic Matter
Fact Sheet
Soil organic matter contributes to soil productivity in many different ways. In this fact sheet, various components of organic matter and the different roles organic matter plays in soil productivity are described as well as field management practices that will help preserve or increase soil organic matter levels over time.

The Effect of Soil Saturation on Trees & Other Plants
Technical Paper
Adequate soil drainage, or lack of adequate drainage (also called soil saturation) is influenced by soil texture (percent of sand, silt, and clay) and structure (arrangement of soil particles).

The Underground Movement (Decompacting urban soils)
In this article, Dr. Glenn Percival, Sean Graham, Pieter Borchardt, and David Challice, discuss the results of an ongoing long-term project aimed at developing a sustainable system for decompacting urban soils.

Neighbors of Arbuscular-Mycorrhiza
Neighbors of arbuscular-mycorrhiza associating trees are colonized more extensively by arbuscular mycorrhizal fungi than their conspecifics in ectomycorrhiza-dominated stands.

Enhancing Soil Fertility & Elevating Pecan Fruit Quality through Combined Chemical & Organic Fertilization Practices
The combined application of chemical and organic fertilizers can significantly increase the soil nutrient content and enzyme activities in pecan orchards to promote the enhancement of fruit quality and economic aspects.

Ohio Urban Site Index Site Analyses
Use this tool for conducting a community soil inventory. The resulting soil inventory will provide valuable information for making local species selection decisions and anticipating existing tree growth and performance.

Rapid Urban Site Index for assessing the quality of street tree planting sites
For an urban site index to have value for urban forestry and arboriculture it must be practical and accurate. Practical considerations include the time and expertise required to use the tool.

Relationship of Structural Root Depth on the Formation of Stem Encircling Roots & Stem Girdling Roots: Implications on Tree Condition (Hauer, et al 2021)
The data collected from this study, combined with the robustness of the sample size, and the analysis of said data, presents a conclusion that is unlikely to be coincidental and is supported by past research. Incremental additions of soil over the structural root systems of younger trees (approximately 20 years or less) did affect the condition of the four species, did increase the frequency of stem encircling roots, and did increase the frequency of stem girdling roots.

Synergistic Effects of Biochar and Other Eco-Friendly Fertilizers on Soil Health & Plant Productivity (Joshi, et. al 2023)
Although biochar has been promising in solving various soil-plant-related issues, it still has several drawbacks. Utilizing biochar in conjunction with other fertilizers that are known to improve soil health and environmental sustainability can help to some extent overcome these restrictions.

Towards an Improved Rapid Urban Site Index
This study investigated three knowledge gaps in the current RUSI.

An Arboriculture Treatment of Biochar, Fertilization, and Tillage Improves Soil Organic Matter & Tree Growth in a Suburban Street Tree Landscape in Illinois (Scharenbroch, et al. 2022)
Results indicated that the BFT treatment positively affected urban tree growth, with Acer rubrum trees showing significantly greater relative height growth compared to tillage alone. Soil parameters, including total soil organic matter (SOM), particulate soil organic matter (POM), and a soil quality index (SQI), were also significantly higher in the BFT treatment compared to tillage alone. The hypotheses tested in the research included the effectiveness of tillage alone, the marginal improvement with tillage plus fertilizer and biochar, and the maximum improvement in soil quality and tree health with tillage plus fertilization and biochar treatment.

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