Silviculture NOTES

Professor's lecture notes only

What is Morphological Assessment, and what attributes does it assess (5)?

Is done to ensure the growth schedule is on target and for grading

• Shoot Length (height)

• Stem Diameter

• Height to diameter ratio

• Shoot to root ratio

• Terminal bud activity

What are the (7) Physiological Assessments

• Frost hardiness - Electrolyte leakage method

• Electrical impedance - Determines when bareroot seedlings are ready for lifting and cold storage.

• Chlorophyll fluorescence - Non destructive measurement of the integrity of the photosynthetic systems

• Photosynthesis

• Plant moisture stress - Pressure chambers used to measure level of moisture stress in seedlings

• Stress-induced volatile emissions - Stressed seedlings produce a number of gasses. These gasses are recorded to monitor level of stress

• Root growth potential (RGP) - Seedlings are placed in mist chambers or hydroponic systems or soils to count the number of white root tips. It is an indicator of potential not actual performance.

What to look for (7) for insect and diseases field assessments

Smell - Sweet fermentation = heating during storage or excessively wet stock

Needle color - Discoloring = heated or stored without ventilation for too long

Bud - Firm/ no sign of new growth = dormancy

Temperature - should be cool, roots moist

Molds - free of

Bark - Healthy, firm, uniform

Roots - Check for damage

Container can refer to __ __ or ___ __

single cell or entire block

Individual containers referred to as ____ or _____

cells or cavities

Individual containers are produced in aggregates called… (3)

blocks, trays, or racks

Seedlings grown in containers are called... (3)

Containerized seedlings

Container grown seedlings

Container seedlings

Characteristics of containers for forest nurseries

Container size - depend on biological (size of seedling/sapling/species) and economical factors.

Container spacing - Distance between individual cells in the block. Affects the growth and characteristics of seedling

Design feature for controlling root growth - Most serious problems is root spiral. Solution is vertical ridges, ribs, or grooves

What is chemical pruning?

Coating interior walls of the container with root growth inhibiting chemicals.

Container properties affecting growing medium moisture content (3)

• Height - Taller = Well drained

• Properties of container wall - Permeable walls allow nutrients to move between adjacent walls, so they may need more coarse growing medium

• Drainage holes - large enough so they will not be plugged by roots

Container properties that affect nursery operations

Nursery - Bench design, growing density, type of growing medium, type of filling/sowing equipment, fertilization/irrigation systems, type of transplanting machine and species

Planting - Handling, transportation, planting tools

Cost/Availability - purchasing price, transportation, storage, durability, reusability

Ability to monitor growing medium condition and root growth - Some containers can be opened to see roots and growing medium

Ability to interchange/consolidate containers (unitization) - Unwanted individual cells can be removed

Handling, shipping, storage - Containers must be sturdy enough to withstand repeated handling and moving

Container materials used in growing seedlings, (3) pros and cons

Molded Peat Moss or Wood Fiber - CONS - roots can penetrate wall and grow into adjacent cell, lack of anti spiraling features, prone to algae and mold. PROS - Short term usage

Biodegradable Hard Plastic - PROS - Container should expand and decompose to allow roots to grow out. CONS - Performance of decomposition is inconsistent

Paper Pots - PROS - Most successful, easy to decompose. Modifications such as copper coated strips prevent roots growing into adjacent cells CONS - Rate of decomposition depends on local soil and climate

Medium characteristics related to nursery operations (8)

1. Reasonable Cost and Availability

2. High Degree of Uniformity and Reproducibility

3. Low Bulk Density

4. Dimensional Stability

5. Durability and Ease of Storage

6. Ease of Mixing and Filling into Containers

7. Ease of Rewetting

8. Promotion of Firm Root Plug Formation

Comparisons Between Commercial / Custom Mixing of Growing Medium (5)

1. Control Over Quality

2. Ability to fine tune

3. Time, Labor, Equipment

4. Incorporation of fertilizers and other amendments

5. Uniform mixing

What are the two kids of nutrient absorption for trees

Active

Passive

What are the 4 kinds of nutrient concentration in plant materials

• Deficiency Range - Symptoms of nutrient deficiency show

• Optimum Range - Growth Peaks

• Luxury Consumption Range - Beyond optimal range, growth does not increase

• Toxic Range - Nutrients now dangerous for plant, can kill

What are the (3) Macronutrients

Nitrogen (N)

Phosphorous (P)

Potassium (K)

What are the names of the (3) kinds of nutrients

• Macronutrients

• Secondary Nutrients

• Micronutrients

What are the (3) secondary nutrients

• Sulfur (S)

• Calcium (Ca)

• Magnesium (Mg)

What is used as a pH adjustor for high pH water

Phosphoric acid

Plant water potential is always more ____ than growing medium water potential

negative

Water always moves from _____ water potential to areas with ____ water potential

water always moves from lower (more negative) water potential to areas with higher (more positive) water potential.

Water quality is affected by the concentration of what? (3 ish)

Dissolved salts

Pathogenic fungi, weed seeds, algae

Pesticide Contamination

How does humidity impact seedling growth?

Not directly, it influences internal water status of the tree, moisture content of the growing medium and the development of pathogens which impacts the growth and development

Affects of dry air (low humidity) and water stress on a tree

Dry air increases transpiration water loss. This excessive water loss can lead to internal water deficiency (water stress). Increases the rate of evaporation from the growing medium, leading to soil drought unless water frequency is high.

Water stress limits the rate of photosynthesis and growth

Effects of high humidity

Reduces the rate of transpiration. Very high humidity encourages the spread of pathogens, so an optimum range is ideal

What is ideal humidity of each growing phase?

Establishment phase - keep seed and surface growing medium moist, but too frequent irrigation can produce water logging and encourage pathogen growth. High humidity (60-90%)

Rapid growth phase - 50-80% so that surface growing medium and foliage will be kept dry. Free water on plant surface encourages pathogens

Hardening phase - Humidity should be reduced even more to induce water tress, which will slow down height growth and promote bud set

Methods to modify humidity in container nurseries

Steam - Increase temp and humidity

Fog and mist - Fog water droplets small enough to remain suspended in the air for a few minutes then evaporate. Mist droplets are larger and will settle onto surfaces in a few seconds and evaporate. Fog systems better but more expensive because of high water pressure

Irrigation - Brief intervals of irrigation will increase the air humidity, but over irrigation will wet foliage, saturate growing medium and promote fungal disease

Conservation of humidity - Well sealed greenhouses trap moisture released from rapidly growing seedlings. OR decrease humidity with ventilation or heating.

How to monitor humidity

Psychrometer ( dry and wet bulb thermometer)

Hygrothermograph

Electronic hygrometer

How is temperature related to humidity

Heating will decrease humidity but does not change the total amount of water vapor

What are the properties of light that are important to plants?

Intensity - A quantitative measure of light (photon flix density)

Duration - length of lighting period (day length)

Quality - spectrum of light

Define photoperiodism

The response of plants to the relative length of day (photoperiod)

What is phytochrome

It is a light sensitive photoreceptor protein in plants that regulates growth and development by detecting red and far red light. The response to the photoperiod is controlled by the phytochrome

What are the two forms of the phytochrome

active (red light) and inactive (far red light)

There is more red light during the day and more far red light during the night

What are the light requirements of each phase of seedling development

Establishment phase - relatively low light, with light quality and photoperiod being the most important.

Rapid growth - Light intensity should gradually increase to above the saturation point for photosynthesis. Photoperiod should be maintained at optimum for growth during this phase

Hardening Phase - Shortening photoperiod to or below the critical length is important for the initiation of bud setting and cold hardening during this phase

How to modify the photoperiod in nurseries

Selecting an artificial light source. Light bust have a high enough red to far red light ratio and a high enough light intensity. Incandescent lights are recommended

Shading the greenhouse to decrease photoperiod

Shade from nearby trees can affect lighting in the greenhouse

What are the two methods of extending photoperiod?

Continuous

Intermittently

What are the three patterns of lighting for both continuous and intermittent lighting

Night break lighting - light is supplies for a few hours in the middle of the night, breaking it into two shorter dark days

Daylength extension lighting - Light is supplied before dawn and/ or after dusk

All night lighting - Light is supplied throughout the night

Why should artificial lights be used only as a supplement to natural light

It is expensive, so boosting natural light is ideal

When is shortening photoperiod necessary

when budset and cold hardening need to be initiated in the summer. curtains can be used to shade the greenhouse, and it will also provide insulation

How to monitor light

Measured with photometer, radiometers, and spectral radiometers

Light control systems

Lights can curtains can be switched on and off automatically by a photocell, a timer or a computerized control system

What is the role of CO2 in growth and development?

It is the raw material for photosynthesis. High CO2 = positive photosynthesis , but too light and it can close the stoma and shut down photosynthesis

Generally increasing CO2 is a good thing until another factor is limited

What is the CO2 compensation point?

The CO2 concentration at which the rate of net photosynthesis equals zero

CO2 requirements in different growth phases

Establishment phase - Unsure, because of plant surface area, CO2 effects are minimal

Rapid growth phase - up to 1000 ppm

Hardening phase - CO2 needs decline

How to monitor CO2

Hand held tester or infrared gas analyzer

CO2 control systems

control systems, such as pressurized gas tanks can be wired with lights and irrigation to turn on at the same time.