Lecture 3

Week 1 Overview

Course: Principles of Botany
Week 1 focus: Introduction & Plants and People
Key themes: Urban Heat Island Effect (UHI), Inequality in plant services, Ecosystem services

Current Problems and Plant-Based Solutions

Topic: Climate change impacts on oceans, weather, plants, animals, and humans
Transcript states: Depleted ozone has created a greenhouse effect; warming impacts are widespread
Plant-based solutions proposed:
- Carbon sequestration
- Biofuels (algae)
- Cooling impacts from trees
Constraints and limiting factors for plant-based solutions:
- Droughts
- Nutrient demands
- Space limitations
- Cost
Example tree note: Tulip tree (Liriodendron tulipifera) on ISU quad grows tall but with few lateral branches, illustrating growth form considerations in design

Street Tree Selection: Factors to Consider

Question to answer: What tree should be chosen for the street?
When selecting, consider two sets of factors:
- Aspects of the tree
- Life span
- Species and tolerance
- Appearance
- Crown size
- Height
- Growth rate
- Litter production
- The environment
- Proximity to poles and underground utilities
- Soil compaction
- Accessibility to water
Additional considerations:
- Diseases
- Cost
- Public perception
- Biodiversity and diversity of species on the street

Devastating Diseases: Elm Anatomy and Visual Cues

Plant anatomy terms relevant to disease discussions:
- Heartwood
- Sapwood
- Living phloem
- Periderm (Cork)
- Vascular cambium
Leaf status indicators:
- Green leaves = functioning
- Yellow leaves = wilted / stressed
Figure identifiers observed in the transcript (likely image references):
- 5478046
- 5511521

American Elm and Dutch Elm Disease (DED)

Major species mentioned:
- American Elm, Ulmus americana
Dutch elm disease (DED) impact:
- DED historically killed $ext{approximately } 10^9$ elms (1 billion elms) and counting
Structural impact of DED on tree tissues remains linked to vascular system disruption (tissue labels: living phloem, cambium, etc.)
Descriptive note: "cathedral-like canopies" referenced to elm growth form before disease impact

Campus Trees and Historical Context

Campus tree composition note: About 90% of trees on UIUC campus were American elms, per John Franch (Illinois)
Historical note: In 1880, Fell Arboretum contained 38 species; President Felmley stated, “The campus should contain every species of tree and shrub that will live in the open air in this latitude.”

Princeton Elm Accession (Case Example)

Building Name: Horton Field House
Accession #: 01-2023-0067
Location: Northeast of Horton Field House
Campus Zone: Northwest (03)
Family: Ulmaceae
Common Name: Princeton elm
Botanical Name: Ulmus americana 'Princeton'
Genus: Ulmus
Species: americana
Area Key: 10W
Cultivar: Princeton
Dedication: Not Applicable
Designation: Tribute
Designee: (none listed)
Growth Habit: Tree
Ceremony: Arbor Day
Planted Date: $4/26/2023$

Urban Heat Island Effect (UHI)

Definition: Urban heat islands are areas with higher energy costs, higher air pollution levels, and more heat-related illnesses because natural land cover (trees, grasses, shrubs) has been replaced with pavement and buildings that retain heat
Implications: Higher local temperatures, increased cooling loads, and degraded air quality

Reducing the Urban Heat Island Effect

Strategies:
- Plant trees and grasses in barren areas, right-of-ways, under solar panels, etc.
- Choose native, drought-tolerant plants
- Plant to maximize shade
- Fund green improvement projects
- Install green roofs
Additional note: Green roofs can improve air quality by absorbing pollutants
Example project: Chicago Botanic Garden – Conservation Science Center runs major trials on which plants perform best for green roofs in the country

An Evaluation Study of Plants for Use on Green Roofs

Author/Lead: Richard Hawke, Plant Evaluation Manager
Focus: Evaluation of plant selections for green roofs

North Green Roof Display Beds

Visual/educational reference to green roof display beds on the north side

Ecosystem Services and Plant Contributions

Definition: Ecosystem Services – benefits that wildlife or ecosystems provide to people
Categories:
- Provisioning Services: tangible goods that can be harvested or extracted (e.g., food, oil, timber, etc.)
- Regulating Services: processes that regulate environment (e.g., pollination, water purification, erosion control, etc.)
- Cultural Services: non-material benefits (cultural, social, recreational, aesthetic values)
- Supporting Services: fundamental ecological processes that support all other services (e.g., nutrient cycling, water cycle, biodiversity maintenance)
How plants can help address problems:
- Create shade to reduce cooling demand and associated CO2 emissions from air conditioning
- Sequester and store carbon via photosynthesis
- Reduce soil erosion through root systems
- Remove pollutants from water runoff and air
- Provide habitat for pollinators and other wildlife and serve as food sources
- Improve well-being and views of nature

Ecology of Cities and Historical Context (HOLC) – Redlining and Urban Inequality

Historical mapping project (Mid 1930s): Homeowners’ Loan Corporation (HOLC) mapped 239 cities by loan risk using color codes (green to red or A to D)
Concept: “Redlined” neighborhoods were designated as high-risk, often correlating with Black, Catholic, Jewish, or immigrant populations and associated with poor housing and undesirable nearby land use
Reference: Burghardt et al., 2022, University of Richmond
Relevance: Urban form and plant services distribution are linked to historical racial and socioeconomic policies, influencing current ecosystem service access

References and Notable Figures Mentioned

John Franch (Illinois): Noted campus elm abundance on UIUC campus
Felmley (President Felmley): Campus breadth of species philosophy in 1880
Hawke, Richard: Green roof plant evaluation study
Chicago Botanic Garden – Conservation Science Center: Major trials on best plants for green roofs
Burghardt et al., 2022: HOLC redlining study context
Fell Arboretum: Historical diversity and arboretum context

Key Connections and Takeaways

Urban design decisions (e.g., street trees, campus trees) affect ecosystem services, city climate, and human well-being
Historical policies (HOLC redlining) have long-term impacts on neighborhood ecology and access to ecosystem services
Green roofs and urban plantings offer tangible solutions to UHI, air quality, and climate resilience when properly selected and maintained
Understanding tree diseases (e.g., Dutch elm disease) helps guide species selection and urban forestry planning to reduce risk
Documented institutional practices (arboretum goals, campus planting records) provide models for biodiversity, resilience, and educational outreach

Quick Reference Formulas and Numbers

Major historical impact figure: DED elms killed ≈ $10^9$ trees (1 billion)
HOLC city coverage: studied across $239$ cities
Arboretum species baseline (1880 Fell Arboretum): $38$ species
Princeton elm planting date: $4/26/2023$
Campus elm dominance: $90 ext{ extperthousand} imes ext{percent}$ (interpreted as 90% on UIUC campus)
Notation: Key plant science terms include Heartwood, Sapwood, Living phloem, Periderm (Cork), Vascular cambium

Study Prompts (to reinforce the content)

Define Urban Heat Island Effect and list at least three plant-based strategies to mitigate it
Compare and contrast Provisioning, Regulating, Cultural, and Supporting Ecosystem Services with examples
Explain why street tree selection requires balancing tree traits with urban infrastructure constraints
Describe the anatomy of a tree section relevant to disease spread (Heartwood, Sapwood, Living phloem, Cambium, Periderm) and what symptoms (green vs yellow leaves) indicate
Summarize the historical HOLC redlining context and its potential implications for current urban ecology and access to ecosystem services
Reflect on how green roofs contribute to city resilience and what factors Hawke’s study emphasizes for plant choices