The Influence of Soil Decompaction & Amendments on Soil Quality
Percival et al., Arboriculture & Urban Forestry 2023
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
Donovan, Arborist News 2020
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
Vogt, et al. Arboriculture & Urban Forestry Review 2015
Over 300 articles were compiled, of which 163 were deemed useful for this review document.

A Review on Defence Responses and Resistance Breeding in Forest Tree Species
Dasgupta 2020
Forest trees play an important role not only in mitigating the effects of climate change but also in maintaining proper ecosystem stability and considerable economic and ecological value. They are a vital source of alternative bioenergy and play important roles in pollution abatement and biodiversity maintenance. 

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.

Heat Tolerance of Urban Trees 
Percival 2023
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? 
Walton, Smith, 2022
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
Chalker-Scott, J. Environ. Hort 2007
All mulches are not created equally. 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
Eyles, et al., Tansley Review 2009
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
Bonello 2009
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
Scharenbroch, Arboriculture & Urban Forestry 2009
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.

A rapid urban site index for assessing the quality of street tree planting sites. 
Scharenbroch, et al., Urban Forestry & Urban Greening 2017
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.

Quantitative Tools for the Prediction of Pavement Damages Associated with Urban Trees
Lee, Arboriculture & Urban Forestry 2022
This study of 1,100 urban trees in Hong Kong found that trunk diameter was strongly related to sidewalk damage, with each centimeter of diameter increasing root protrusion likelihood by 1.015-1.114 times. The size of the tree pit was a better predictor of the length of protruding roots, while leaning trees had a higher likelihood of protruding roots. This work reinforces the need to select species based on mature size, ensure adequate pit dimensions, and proactively enlarge pits using trunk diameter as a guide for timing interventions.

The Complex Issue of Urban Trees—Stress Factor Accumulation and Ecological Service Possibilities 
Czaja, et al. 2020
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
Raupp, Arborist News 2014
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.

Tree Establishment: A Review of Some of the Factors Affecting Transplant Survival & Establishment
Struve, Arboriculture & Urban Forestry 2009
The transplant survival of any tree is more than just proper planting. Production methods, shipping, and other factors play a role in establishment. This article provides research-supported information on some of the less thought-of influences on tree planting and survival past the initial establishment period.

Armillaria Root Disease
Williams, et al., Forest Insect & Disease Leaflet 2016
The disease is caused by fungi, which live as parasites on living host
tissue or as saprophytes on dead woody material. The fungus most often
identified as causing the disease is Armillaria mellea (Vahl: Fr.)
Kummer. Recent research, however, indicates that several different but
closely related species are involved. Therefore, the generic term
Armillaria is used to refer to this group.

Bacterial Wetwood & Slime Flux of Landscape Trees
University of Illinois Extension 1999
Bacterial wetwood, a water-soaked condition of wood, occurs in the trunk, branches, and roots of many shade and ornamental trees, but is often not obvious in trees less than 10 years old. Wetwood is most prevalent and causes the most damage to elms.

Beech Bark Disease
Houston, O'Brien, USDA 2017
The disease results when bark, attacked and altered by the beech scale, Cryptococcus fagisuga Lind., is invaded and killed by fungi, primarily Nectria
coccinea var. faginata Lohman, Watson, and Ayers, and sometimes
N. galligena Bres.

Beech Leaf Disease Severity Affects Ectomycorrhizal Colonization and Fungal Taxa Composition
Bashian-Victoroff, et al., Journal of Fungi 2023
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
Wang, et al., 2008
The management of silver maple canker diseases should be based on integrated pest management (IPM) principles. This guideline for professionals and homeowners provides more information.

Boxwood Blight
Gauthier, Dockery, UK Plant Pathology Fact Sheet 2018
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
Ruhl, et al., Perdue Extension 2020
Boxwood blight is a fungal disease easily transported in the nursery industry. It can be moved on infected plants that do not show symptoms at the time of shipment.

Boxwood - Volutella Blight
Baysal-Gurel, Liyanapathiranage, TN State University 2016
This disease is causing extensive losses in commercial nurseries that produce boxwood.

Comparative Assessment of Phosphite Formulations for Apple Scab
Hailey, Percival, Arboriculture & Urban Forestry 2014
The greatest increases in fruit yield and leaf chlorophyll content (SPAD values) were achieved after spraying the synthetic fungicide penconazole where values were 53.1% and 88.8% higher than controls, respectively.

The Influence of Chitin-Based Soil Amendments on Pathogen Severity of Apple & Pear Scab  
Percival, et al., Arboriculture & Urban Forestry 2023
Penconazole proved very effective for apple and pear scab control in 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.

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. 

Fungicidal Activities of Soil Humic/Fulvic Acids as related to their Chemical Structures 
Meng Wu, et al., Scientific Reports 2016
In this study, soils with a chronosequence in greenhouse vegetable fields were collected, and the soil humic acids (HAs) and fluvic acids (FAs)were extracted and purified. For the first time, the soil HAs and FAs were found to show inhibition activities against phytopathogenic fungi. 

Hypoxylon Canker
Clemson Cooperative Extension 2010
Hypoxylon canker is a white-rot fungal disease primarily of oaks, hickories, and pecans. Environmental stress caused by drought, as well as by root injury during construction, utility trenching in the root zone, soil grade changes, soil compaction and root diseases, all can play a role in weakening the trees and in the subsequent infection

Phosphite Injections & Bark Application of Phosphite + Pentrabark Control Sudden Oak Death 
Garbelotto, et al., Arboriculture & Urban Forestry 2007
Therapeutic phosphite injections effectively reduced the growth of P. ramorum in artificially inoculated potted coast live oak trees as determined by the size of lesions.

Phosphonate Treatment Effects on Phytophthora Root Rot Control, Phosphite Residues & Phytophthora cactorum Inoculum in Young Apple Orchards 
Nyoni, et al., Plant Disease 2021
This study showed that in three apple orchard trials, phosphonate treatments could significantly improve tree growth (increase in trunk diameter) in one orchard and yield in a second orchard when young apple trees suffered from Phytophthora root rot, 25 months post-treatment application. In general, phosphonate application methods and dosages were equally effective at significantly increasing tree performance and suppressing P. cactorum root inoculum. 

Is Phytophthora cinnamomi a Causal Agent of Oak Decline in Southern Ohio? 
Nagle, et al., 2014
The presence of higher inoculum densities of P. cinnamomi in declining stands provides circumstantial evidence that it contributes to white oak decline.

Influence of site and rate of low-volume aerial phosphite spray on lesion development of Phytophthora cinnamomi and phosphite persistence.
Shearer, Crane, 2009
The effective control of P. cinnamomi by low-volume phosphite spray will depend on efficient uptake, long-lasting action, and a correlation between effective dose and inhibition of the pathogen. Phosphite uptake increased with increasing phosphite dosage applied but varied greatly between plant species and environment.

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 in plant health after application of potassium phosphite is related to an increase in resistance against a variety of plant pathogens and increased tolerance of many environmental stress factors, including drought stress.

The Potential of Mulch to Transmit Tree Pathogens 
Jacobs, Journal of Arboriculture 2005
Infected needles and shoot tips collected from diseased pines and then used as mulch transmitted S.sapinea to healthy saplings in the field.

Seasonal & Regional Distributions, Degree-Day Models, & Phoresy Rates of Major Sap Beetle Vectors of the Oak Wilt Fungus
Jagemann, et al., 2018
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 that 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. 

Susceptibility of Garden Trees and Shrubs to Armillaria Root Rot
Cromey, et al., Plant Disease 2020
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 using host resistance as part of the integrated management of ARR.

Tubakia Leaf Spot
Bartlett Research 
Tubakia leaf spot, also known as Actinopelte leaf spot, is caused by the fungus Tubakia sp. (formerly Actinopelte). This late-season fungal disease commonly attacks oaks, particularly those in the red oak group (black, red, 
and pin oak). Tubakia has also been reported on chestnut, maple, elm, ash, hickory, tupelo, redbud, sassafras, sumac, and sweetgum. This distinct fungus is probably distributed worldwide, but it has been reported primarily east of the Mississippi in the United States.

Wood Decay Fungi in Landscape Trees
UCIPM Pest Notes 2019
Several fungal diseases, sometimes called heart rots, sap rots, or canker rots, decay wood in tree trunks and limbs. Under conditions favoring the growth of specific rot fungi, extensive portions of the wood of living trees can decay in a relatively short time (i.e., months to years). Decay fungi reduce wood strength and may kill storage and conductive tissues in the sapwood. While most species of woody plants are subject to trunk and limb decay, older and weaker trees are most susceptible.

Ambrosia Beetles
Bartlett Research 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
Redmond, Potter, Arboriculture & Urban Forestry 2017
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
Meidl, et al., 2024
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 
Raupp, et al., 2009
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 
Herms 2002
This research focuses on how fertilization impacts the dynamic between insect pests and woody ornamental plants: namely, the tendency to allocate resources towards growth and away from defense and an increase in the nutritional value of host plants, benefiting the pest. Additionally, the study addresses the notion that fertilization helps trees recover from defoliation, a claim for which the author can find no supporting evidence.

Factors Affecting the Efficacy of Trunk-Injected Emamectin Benzoate to Manage Emerald Ash Borer
Sadof, et al., Arboriculture & Urban Forestry 2022
This paper provides the results of studying three different trunk injection delivery systems and the number of injection ports installed in the tree. The important question was how many ports are needed to get the appropriate distribution in the crown for effective control. Fewer ports and fewer wounds are always the goal. However, the distribution in the tree may be a consequence.

Field Guide to the Jewel Beetles of Northeastern North America
Canadian Food Inspection Agency 2012
The past decade has seen an increased interest in the jewel beetles (Coleoptera: Buprestidae) of northeastern North America, largely in response to the accidental introduction of Emerald Ash Borer (Agrilus planipennis) in the 1990s. The need for accurate data on the spread of Emerald Ash Borer has resulted in several independent jewel beetle monitoring projects, undertaken by federal, provincial, and university researchers in Canada and the USA. As a result, the northeastern jewel beetle fauna has been recently sampled at an unprecedented intensity and scale. 

Observation of External Wounding on Green Ash Trees Associated with Tree Injection Systems  
Hauer, et al., Forests 2022
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 
Habash, Al-Banna, Journal of Nematology 2011
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
Jagemann, et al., 2018
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. 

Airspade: The Root of the Problem 
Benson, Morgenroth, Tree Matters 2021
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
Schaffert, et al., Arboriculture & Urban Forestry Review 2022
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., Journal of Environmental Quality 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.

Cation Exchange Capacity (CEC)
Cornell University Fact Sheet 2007
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
Nardi, et al. 2000
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.

Combined application of up to ten pesticides decreases key soil processes
Meidl, et al., Environmental Science & Pollution Research 2004
This research highlights pesticides' complex impacts and the need for environmental policy to address their threats.

Compost improves soil properties and tree establishment along highway roadsides
McGrath, et al., Urban Forestry & Urban Greening 2020
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.

Effect of Compost-amended Backfill & Paved Surface on Leaf Parameters & Physiology of Norway Maple 
Ferrini, Baletto, et al., Arboriculture & Urban Forestry 2007
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.

Effect of Leonardite Application on Leaf Nutrient Content & Fruit Chemical Parameters of Cherry
Demirer 2019
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. 

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

Enhancing Soil Fertility & Elevating Pecan Fruit Quality through Combined Chemical & Organic Fertilization Practices
Tong, et al., Horticulturae 2023
In summary, 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.

Exploring Management Methods for Beech Leaf Disease, an Emerging Threat to Forests and Landscapers
Loyd, et al., Journal of Environmental Horticulture 2024
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. 

Fertilization and Soil Microbial Community: A Review
Dinca, et al., Applied Sciences 2022
Several papers have highlighted the negative effects of chemical fertilization, especially the decrease in enzymatic activity in soils that have received the largest amounts of fertilizers, together with losses in organic matter.

Fish By-Product Use as Biostimulants: An Overview of the Current State of the Art, Including Relevant Legislation and Regulations
Madende, Hayes, 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.

Fungicidal activities of soil/humic/fulvic acids as related to their chemical structures in greenhouse vegetable fields with cultivation chronosequence  
Meng Wu, et al., Scientific Report 2016
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.

Effect of K-N-Humates on Dry Matter Production and Nutrient Use Efficiency of Maize  
Chaddy, et al., 2010
Composting and its main attribute, i.e., humic substances, were the focus of this study. The study's objectives were to (1) produce organic K- and ammonium-based organic fertilizer from composted SW and (2) determine the efficiency of the organic-based fertilizer.

Impact of Long-Term Loquat Cultivation on Rhizosphere Soil Characteristics & AMF Community Structure: Implications for Fertilizer Management
Qiang-Sheng Wu, Frontiers 2025
This research article in Frontiers looked at the colonization rates of Arbuscular Mycorrhizal Fungi of Loquat in China. Their findings: significant variation in soil nutrient and enzyme activities in the rhizosphere among different varieties influenced the diversity and richness of AMF. The application of fertilizers diminished AMF diversity. 

Influence of Humic Substances & Nitrogen on Yield, Fruit Quality, & Leaf Mineral Elements  
Fallahi, et al., 2006
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.

Impact of Mulches on Landscape Plants and the Environment  
Chalker-Scott 2007
While this literature review focused directly on plant and soil criteria associated with landscape mulches, other important environmental issues may play a role in the ultimate choice of landscape mulch materials. These issues include environmental degradation associated with the acquisition of some mulching materials, the use of invasive species as ground covers, nutrient overload from overusing organic mulches, and toxic leachates from some synthetic mulches.

Iron and Copper for Citrus Trees  
Zekri, Obrezza, UF/IFAS Extension 2022
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. 

Leonardite Influences Zinnia & Marigold Growth  
Dudley, et al., HortScience 2004
When combined with fertilizer application, zinnia and marigold seedlings and transplants responded favorably to leonardite additions up to 6.25%, and then the response declined.

Microbial Preparations Combined with Humic Substances Improve the Quality of Tree Planting Material Needed for Reforestation to Increase Carbon Sequestration 
Nazarov, et al., 2023
The treatment of plants with humic substances increased nitrogen balance index and chlorophyll content in the leaves of poplar seedlings, which is likely to increase carbon storage due to increased photosynthesis.

Neighbors of Arbuscular-Mycorrhiza
Grunfeld, et al., New Phytologist 2020
Neighbors of arbuscular-mycorrhiza associating trees are colonized more extensively by arbuscular mycorrhizal fungi than their conspecifics in ectomycorrhiza-dominated stands.

Organic Mulch and Grass Competition Influence Tree Rot Development  
Watson, Journal of Arboriculture 1988
Tree root densities were generally higher in the mulch and the 0-7.5 cm soil layer below the mulch.

Plant Health & Soil Changes with Humic Substance Applications
Schroeder 2014
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. 

The Potential of Mulch to Transmit Tree Pathogens 
Jacobs, Journal of Arboriculture 2005
Infected needles and shoot tips collected from diseased pines and used as mulch transmitted S. sapinea to healthy saplings in the field.

Rapid Urban Site Index for assessing the quality of street tree planting sites  
Scharenbroch, et al., Urban Forestry & Urban Greening 2017
An urban site index must be practical and accurate to be valuable for urban forestry and arboriculture. Practical considerations include the time and expertise required to use the tool. 

Towards an Improved Rapid Urban Site Index  
Scharenbroch, et al., Arboriculture & Urban Forestry 2023
This study investigated three knowledge gaps in the current RUSI.

The Role of Biostimulants as Alleviators of Biotic & Abiotic Stresses in Grapevine 
Monteiro, et al., 2022
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.

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.

Effect of Soil Application of Humic Acid & Bio-Humic on Yield & Fruit Quality of Olive Trees 
El-Razek, et 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.

Soil Chemical & Microbiological Properties are Changed by Long-Term Chemical Fertilizers that Limit Ecosystem Functioning  
Bai, et al., Microorganisms 2020
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.

Soil Organic Matter
Cornell University 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.

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. 

The Influence of Soil Decompaction & Amendments on Soil Quality
Percival, et al., Arboriculture & Urban Forestry 2023
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.

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., Arboriculture & Urban Foretry 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.

Tree Growth as Indicator of Tree Vitality & of Tree Reaction to Environmental Stress: A Review 
Dobbertin 2025
International research results and examples from extensive and intensive monitoring plots in Switzerland illustrate how tree growth and transparency can serve as tree vitality or stress indicators, depending on the type and extent of the stress factor. Depending on the time of the stress and the tree compartments affected by the stress, transparency or tree growth may complement each other as stress indicators.

The Underground Movement (Decompacting urban soils)
Percival, et al., Science & Opinion 2020
This article discusses the results of an ongoing long-term project aimed at developing a sustainable system for decompacting urban soils.

Understanding the Role of Humic Acids on Crop Performance and Soil Health
Ampong, et al., Frontiers in Agronomy 2022
This review highlights the relevance of HA on crop growth, plant hormone production, nutrient uptake and assimilation, yield, and protein synthesis. 

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

Soil Fertility Management & Insect Pests: Harmonizing Soil & Plant Health in Agroecosystems
Altieri, et al 2003
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.

Potassium Phosphite
Bartlett Research
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.

Enhancing Soil Fertility & Elevating Pecan Fruit Quality through Combined Chemical & Organic Fertilization Practices  
Tong, et al., 2023
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.

Wielding the A300 Standards Webinar

The ANSI A300 Standards are a documentation of what industry stakeholders can agree upon within the context of the ANSI approval process. When wielded correctly, they can form powerful legal weaponry to use both defensively and offensively. In this webinar, you will learn how to limit your liability when performing risk assessments by following the mandatory requirements. Learn how to avoid offensive strategies by plaintiffs that attack insufficiency of inspections, reports, and pruning practices.

Compost improves soil properties and tree establishment along highway roadsides
McGrath, et al., Urban Forestry & Urban Greening 2020
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.

Effect of Compost-amended Backfill & Paved Surface on Leaf Parameters & Physiology of Norway Maple 
Ferrini, Baletto, et al., Arboriculture & Urban Forestry 2007
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.

Microbial Preparations Combined with Humic Substances Improve the Quality of Tree Planting Material Needed for Reforestation to Increase Carbon Sequestration 
Nazarov, et al., 2023
The treatment of plants with humic substances increased nitrogen balance index and chlorophyll content in the leaves of poplar seedlings, which is likely to increase carbon storage due to increased photosynthesis.

Effects of Planting Depth on Landscape Tree Survival & Girdling Root Formation
Wells, et al., Arboriculture & Urban Forestry 2006
The results of this study support the hypothesis that deep planting can predispose trees to transplant failure and girdling root formation. Although the effects of deep planting will certainly vary with species and site conditions, the few extra minutes needed to identify a tree's root collar and place it at grade could mean the difference between its survival and failure in the landscape.

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 Effects of Harvesting Short Rotation Cottonwood with Tree Shears in Arkansas
Pelkki, et al., 2014
This study applies to land clearance, UVM, and land management. They found a higher rate of mortality when cutting with skid steer-mounted shears vs. traditional chainsaw cutting. The higher mortality rate would be a positive in UVM or land management (for lumber/pulpwood stands) or a negative for regenerative biomass harvesting (high-volume biomass harvest for wood pellets). One year after harvest, 84 percent of the chainsaw-felled trees were alive, while only 60% of the sheared trees had survived. While both felling methods were performed during November/December, felling at the end of the growing season in September may have resulted in higher sheared survival based on reduced soil disturbance from machinery in the drier season.

Likelihood of Failure of Trees Along Electrical Utility Rights-of-Way
ISA ReviewWalker, Dahle, Arboriculture & Urban Forestry 2022 
Utility vegetation managers need tools to predict tree-related risks and knowledge of the necessary management prescriptions to reduce the risk of windthrow damage to utilities' electrical infrastructure. This ISA literature review focuses on key studies involving the likelihood of failure of trees.