Site Assessment Prepared by Cornell Cooperative Extension and
Site Assessment Prepared by Cornell Cooperative Extension and Cornell’s Urban Horticulture Institute for the NYS Department of Conservation and FEMA
The Planting Process Plant Selection Transplanting Techniques Site Assessment Site Modification
Course Overview Core Curriculum Workshops to develop assessment skills Tours to hone site assessment skills Role-playing scenarios Case studies Take-home reference resources
Site Assessment A methodical inspection of a site in order to learn more about the site’s ability to support healthy plant growth.
Site Assessment: an important managment tool Enhances your professional status Improves customer satisfaction Enhances your profitability • lowers replacement costs • maximizes worker productivity
Case Study Planting Costs: $10, 000 Replacement Budget: $2, 500 Replace 20 Sugar Maples 20 x $200 = $4, 000 Replacement budget -$2, 500 Loss on the job ? ? ? ? Alternative: site assessment notes difficult growing conditions and plant selection is changed to use a more site-tolerant species
Benefits of Site Assessment Instills positive image about the professionalism of your services Increases profits Increases customer satisfaction Thriving plantings reflect well on your company and industry as a whole
Basic Requirements for Plant Growth Oxygen Water Light Minerals Carbon Dioxide Appropriate Temperatures
Roots--General Morphology Roots extend 2. 5 -3 times the crown radius Most roots (>60%) located outside the drip line Tap roots rarely present in mature trees Water and nutrients absorbed by root hairs Root hairs primarily located in top 6” of soil >95% of roots are found in the top 3’ of soil
Root Functions Absorb water and nutrients Provide stability Synthesize plant hormones Store energy produced by plant
Shoot Functions Photosynthesis Transport sugars from source to sink Synthesizes plant hormones
Summary of Plant Structure and Functions All plants have certain basic requirements for healthy plant growth Different species will be differently able to tolerate different growing conditions Most tree roots are located in the top 18” of soil and extend 2 -3 times the crown radius
Factors to Consider Climate and Microclimate Structural factors limiting canopy and rooting space Soil Factors Existing vegetation Design factors Legal factors
Climate USDA Hardiness Zone Precipitation 7 a 6 b 6 a 5 b 5 a 4 b 4 a 3 b
Microclimate: Site Specific Sunlight Rereflected heat Wind Frost Pockets
Rereflected Heat Increases temperature Decreases humidity Increases water stress
Structural Factors Limiting Canopy and Rooting Space Above Ground • Determine amount of canopy space available • Note location and height of overhead wires Below Ground • Call UFPO to locate underground utilities • Buried debris may alter soil characteristics and limit rooting space
Soil Factors Soil Texture Soil p. H Soil Compaction Soil Disturbance Effective Rooting Depth and Volume Drainage and Aeration Topography Soil Cover Soil Contaminants
Soil Texture Amount of Sand, Silt and Clay in a Soil 100 0 Percent Clay Sandy clay Clay loam Loamy sand Sandy loam 0 100 Percent Silt Clay Loam Silty clay loam Silt loam Percent Sand Silt 100 0
Properties of Soils of Different Textures Soil Texture Susceptibility to Compaction Nutrient Holding Capacity Sand Loam Clay limited moderate high limited moderate to high Available Water 7% (% of volume) 16% 11% Infiltration Rate high moderate low
Growth Increment
Soil Structure Good Structure Macropores Poor Structure Macropores Micropores Soil Particles
Effects of Compaction on Soil structure is destroyed Soil drains slowly and is often anaerobic Compacted soil physically impedes root growth and results in the containerization of roots
Soil Compaction and Construction Soil structure is slow to form, but quick to destroy The first pass of heavy machinery causes the most damage Plan ahead to preserve soil structure
How Much Soil Does a Tree Need? 2 cubic feet of soil for every 1 square foot of crown projection Crown projection
Salt Injury to Plants Excessive salt levels in the soil • Limits water and nutrient uptake by roots • Increases likelihood of soil compaction • Chloride accumulates in toxic levels in plant and leads to marginal leaf scorch Salt spray damage • Buds and tips of plant have greater likelihood of freeze damage
Analyzing Existing Vegetation Identify plant species Note any indications of plant stress Determine annual growth increment of existing trees Check for salt injury Look for mechanical damage Note presence of any noxious weeds
Indications of Plant Stress Small, scorched or off-color foliage Early fall color or leaf drop Tip dieback Presence of insects or disease Suckering from the trunk
Design Factors Landscape Function • aesthetics • screening or enhancement of views • reinforcing public or private space Circulation • Pedestrian and vehicular traffic patterns • events that increase people pressure
Legal Factors Establish property boundaries, easements and right-of-ways Determine if site is within a special jurisdiction • historic preservation areas • community ordinances • tree preservation districts Determine permitting process
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