To boldly grow where no one has grown before Bert Cregg, Ph.D. Michigan State University Department of Horticulture Department of Forestry Photo: Dennis Fulbright Presentation outline Key landscape site factors that limit plant growth and development Soil drainage/flooding Soil ph-alkaline soils Shade Drought Deicing salt 1
Poor drainage/flooding It s raining, it s pouring, It s a good time for a site assessment Poor drainage/flooding Why are flooding and poor drainage problems? Lack of oxygen to roots (anoxia, hypoxia) Reduced nutrient uptake Root rots Sediment build-up Erosion 2
How long can trees withstand flooding? How long can trees withstand flooding? Time of year Trees can withstand flooding longer when dormant than during growing season Species Bottomland species more tolerant than upland species Depth of floodwater http://www.ppdl.purdue.edu/ Why are some trees able to withstand flooding? Above-ground portions can be damage by short periods of inundation Flood tolerance mechanisms Morphology Hypertrophied lenticels Aerenchyma Root regeneration Metabolic adaptations 3
Plane tree Platanus x acerifolia River birch Bloodgood River birch Deciduous conifers are often well adapted to wet soils 4
Dawn redwood Trees that are tolerant or intolerant of Wet soils/flooding Wet/flood Tolerant Red maple River birch Hackberry Honeylocust Sweetgum Dawn redwood London planetree/sycamore Swamp white oak Bald cypress Arborvitae Wet/flood Intolerant Hickory Sassafras Dogwood Red oak American basswood Eastern redbud Black walnut Beech Yellow buckeye Sugar maple Soil ph Alkaline soil Severe iron chlorosis in pin oak 5
ph=-log10[h+] Redmond linden ph 6 is 10x as acidic as 7 ph 5 is 100 x as acidic as 7 6
Triumph elm 2004 Triumph elm 2014 Kentucky coffeetree Gymnocladus dioicus 7
Trees that are tolerant or intolerant of alkaline soils Alkaline Tolerant (ph<8.2) Hackberry Honeylocust Kentucky coffeetree Crabapple Dawn redwood American hophornbeam Bur oak Japanese tree lilac Linden (Tilia spp.) Elms (Ulmus spp.) Shade Alkaline Intolerant (ph<7) Colorado blue spruce Red maple River birch Larch Pin oak White oak Hemlock Aspen Dogwood White pine Shade tolerance Forest Succession Foresters classify trees as shade tolerant, shade intolerant or intermediate 8
Acclimation vs Adaptation Acclimation response of an individual - may be short term or transitory Adaptation longer term response of a species Eastern hemlock is adapted to shade but trees may acclimate to grow in full sun Eastern hemlock American Hornbeam Carpinus carolinana Palomino Watnong star 9
Black tupelo Nyssa sylvatica Black tupelo Nyssa sylvatica Trees that are tolerant or intolerant of shade Trees and drought Shade tolerant Concolor fir Sugar maple Buckeyes Dogwood Beech Hophornbeam White spruce American hornbeam Eastern hemlock Tupelo Shade intolerant Paper birch Kentucky coffeetree Black walnut Eastern redcedar Larch Yellow poplar Sycamore Aspen Willow Sassafras Water is the most common factor limiting tree growth and development 10
Atmosphere How does water get to the top of a 300 redwood? Soil Plant Atmosphere Continuum Soil Drought stress avoidance Mechanisms that conserve water or increase water uptake Examples leaf hairs thick leaves increased allocation to roots relative to leaves 11
Drought stress tolerance Mechanisms that enable plants to maintain physiological processes are low plant water potential Osmotic adjustment Increased modulus of elasticity Hackberry Celtis occidentalis Bur oak Quercus macrocarpa Tough tree for tough places Reportedly difficult to transplant Large tree for parks 12
Korean pine Korean pine Trees that are tolerant or intolerant of drought Drought tolerant Bur oak Swamp white oak Honeylocust Hickory Hackberry Ginkgo Walnut Sassafras Elms Baldcypress Drought intolerant Katsura Tulip poplar Willow Hemlock Firs Sugar maple Horsechestnut Japanese maple River birch Dogwood Salt damage on Callery pear Deicing salt In the Great Lakes region, 100-300 lbs of deicing salt are applied per lane mile for each event 13
Effect of distance from road Trees and road salt Baldcypress Direct toxicity Reduced cold hardiness Soil impacts Osmotic stress Altered soil structure Displacement of cations 14
Miyabei maple Ginkgo Ginkgo biloba Trees that are tolerant or intolerant of salt exposure Salt tolerant Hedge maple Ohio buckeye Ginkgo Kentucky coffeetree Eastern redcedar Red oak Swamp white oak Bur oak Japanese tree lilac Baldcypress Salt intolerant Red maple Sugar maple Hornbeam Tuliptree Hophornbeam Pin oak Linden (Tilia spp.) Black walnut White pine Pin oak 15
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Questions? Comments? 18