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Why need to understand how roots and mycorrhizas interface with the ecosystem:. Roots/mycorrhizas research exist a black hole and difficult to study because can’t see them expect in wet tropics where roots crawl out of the ground and into tree canopies

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Why need to understand how roots and mycorrhizas interface with the ecosystem:

  • Roots/mycorrhizas research exist a black hole and difficult to study because can’t see them expect in wet tropics where roots crawl out of the ground and into tree canopies

  • Plants obligate relationships with mycorrhizas to survive In less weathered (low nutrient availability ) and highly weathered soils (low nutrient availability, higher toxic chemicals), older growth stages and late successional stages

  • Roots/mycorrhizas allow plants to adapt to their changing soil environment during succession and when soil chemical is altered by human land-use activities

  • Fertilizing forests with a limiting nutrient like N may increase total NPP but reduce fine roots/mycorrhizas. Total NPP increase is not real, just shift allocation of C from below- to aboveground

  • Increasing (during C enrichment of atmosphere) or decreasing carbohydrate production by plants (herbivory) will change amount of mycorrhizas found on roots


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Leached layers where nutrient availability is low with the ecosystem:

Layers that are impermeable to easy root penetration so restrict roots to surface horizons

http://www.hubbardbrook.org/research/gallery/soil/HB_115_Spodosol.jpg

Typical view of the HIDDEN HALF – a black box in soil


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Temperate climatic zones with the ecosystem:

Pacific silver fir tip-over, Findley Lake, Washington

Root tip-over, Kenai, Alaska

This is when we typically see roots


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Temperate climatic zones with the ecosystem:

Temperate Conifer forests – roots located close to surface where most nutrients limiting tree growth foundRoot excavation for tracking disease in Washington (photo Bob Edmonds)


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Temperate climatic zones with the ecosystem:

Temperate Deciduous Forests have deeper soils and are more nutrient rich compared to Conifer Forests. Roots are growing to available nutrients

Canada – Root excavation; Root growth is extensive – can be 30 meters from base of the tree


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Tropical with the ecosystem:Forest Soil

Temperate ConiferousForest Soil

  • Roots / mycorrhizas found more than 30 meters deep

  • Roots not just found in soils

  • Old soils

  • Soils low in Ca, K, N (except where N fixing trees used to shade coffee)

How much soils

weathered

determines where find

ROOTS/Mycorrhizas

  • Roots / mycorrhizas found mainly in the surface organic horizons/soil

  • Young soils

  • Soil nutrient availabilities decrease with land-uses (i.e. acid precipitation)


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Tropical climates with the ecosystem:

http://green.nationalgeographic.com/environment/photos/rainforests-tropical/rhinohornbilldipterocarp.html


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Tropical climates with the ecosystem:

Deep rooted

in highly

weathered soils

Sparse palm trees spread across the savanna of Madagascar. Photograph by Maria Stenzel

http://green.nationalgeographic.com/environment/photos/savannah/palmdottedsavannah.html

Greater rheas graze in the tall savannah grass of Brazil's Pantanal. Photograph by Joel Sartore

http://green.nationalgeographic.com/environment/photos/savannah/rheasgraze.html


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Tropical climates with the ecosystem:

http://travel.mongabay.com/indonesia/images/singapore5485.html

OR roots do not remain in the soil

http://travel.mongabay.com/malaysia/images/malaysia1016.html

http://travel.mongabay.com/indonesia/images/singapore5456.html


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Apogeous roots of Tabonuco climbing up a Sierra palm to acquire stem flow nutrients, Luquillo LTER, Puerto Rico

Nodules of nitrogen fixing tree species (e.g. Inga spp.)

Roots in streams

Tropical climates


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Tropics and Temperate have acquire stem flow nutrients

Root Grafting

Root grafting between different species of plants and borrowing C, nutrients from other plants


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Root rot disease transmitted through root grafts – western hemlock (photo Bob Edmonds)

Roots pass pathogens, carbohydrates, nutrients to other trees in same forest


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Tropics and Temperate hemlock (photo Bob Edmonds)

have mycorrhizal

associations


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Between 60,000 and 1.2 million ectomycorrhizas were found in one square metre of forest and 95% of the root tips examined had formed an ectomycorrhizal partnership.

http://www.nifg.org.uk/ecto.htm


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This is the mycorrhizal fungus one square metre of forest and 95% of the root tips examined had formed an ectomycorrhizal partnershipLaccaria laccata on ponderosa pine. Note the bifuricate shape of the mycorrhizas. You can see the fungal sheath (white area), hyphae, and hyphal strands (if you have 400x vision!).Thank you Jim Trappe for the slide! http://www.cof.orst.edu/cof/teach/for442/cnotes/sec3/myco.htm


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*Cartoon from Masters Thesis UAF one square metre of forest and 95% of the root tips examined had formed an ectomycorrhizal partnership


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The fungus gains carbon  and other essential organic substances from the tree and in return helps trees take up water, mineral salts and metabolites, fight off parasites, predators such as nematodes and soil pathogens.

Indeed, most forest trees are highly dependant on their fungal partners and in areas of poor soil, could possibly not even exist without them.

Thus in forest management, if we do not manage for the mycorrhizal fungi, we could be damaging the trees.

http://www.nifg.org.uk/ecto.htm


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Monotropa uniflora substances from the tree and in return helps trees take up water, mineral salts and metabolites, fight off parasites, predators such as nematodes and soil pathogens. (Canada) is a myco-heterotrophic plant lacking chlorophyll that is entirely dependant on ECM fungi linked to nearby trees.

http://mycorrhizas.info/index.html




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Water Availability floor, Luquillo LTER, Puerto Rico

Nutrient Availability

Regulation point

What controls how much roots and mycorrhizas are produced and supported by plants?

Root Area

Leaf Area


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10 year old Site Class II [ floor, Luquillo LTER, Puerto RicoHIGH SITE QUALITY] Douglas-fir, Washington (note person in photo)

Tree height

10 year old Site Class IV [LOW SITE QUALITY] Douglas-fir, Washington (note person in photo)

Person

Person

Which stand has more fine roots, mycorrhizas??


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Douglas-fir floor, Luquillo LTER, Puerto Rico(% of Total Annual Production)

Control: 30% total NPP in fine roots

Fertilized: 18% total NPP in fine roots


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The Links between Plants (Belowground) & Soils floor, Luquillo LTER, Puerto Rico

Plants

Litterfall

Uptake

Dissolved OM (eg, P, Si, Al)

Decomposition

Uptake

Detritus

Mineralization

Mineralization

Other crystalline & non-cryst Al-Silicate PO4-3 exch sites

SOIL

Imogolite paracrystalline Al-SilicatePO4-3 exch sites/complex

Organic exch sites /complex

Solution


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PNW Pacific floor, Luquillo LTER, Puerto Rico

Silver fir

Example

Oi

Oe

Oa

E

Bhs





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10 parts Ca and 50 parts Al = 0.2 ratio trees were dying from

Abies amabilis, WA

Ca/Al ratio -< 0.2 critical, mortality

Deeper into the soil

10 Ca, 1 Al

10 Ca, 11 Al

10 Ca, 50 Al

10 Ca, 100 Al

SOIL Fine roots < 1mm diam


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Aluminum in Roots by Horizon trees were dying from MRT = mean residence time (yrs) of decaying rootsWhat does it mean to have a long MRT??

Deeper into the soil


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How do you benefit from being an Al accumulator?? trees were dying from

Al accumulator- foliage 500-1,120; fine roots 1320 ppm

Not Al accumulator - foliage 110-260; fine roots 730 ppm


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Wet Nitrate Deposition (kg/ha) 1995-1998 trees were dying from NADP/NTN Monitoring Data


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Spruce dominated stands with co-associates fir, birch, maple trees were dying from

New England

Example

SPODOSOL

http://www.hubbardbrook.org/research/gallery/soil/HB_115_Spodosol.jpg


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ANPP - trees were dying from Tree Species compared to Controls(significant only)

After 6 years treatment


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Alaska succession trees were dying from

No or Facultative mycorrhizal

Obligate mycorrhizal

Courtesy of John P. Bryant


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Alaska Succession trees were dying from

Courtesy of Keith Van Cleve

Courtesy of Keith Van Cleve


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Moose ( trees were dying from Alces alces) and Snowshoe hare (Lepus americanus) excluded from exclosures

Courtesy of John P. Bryant


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Willow and balsam poplar growing outside exclosures had ectomycorrhizal infection reduced by ~ 16% compared to plants protected from browsing for the previous 4 winters

Why care??

Moose and snowshoe hare browsing reduces the supply of soluble carbohydrate available to ectomycorrhizae

Repercussions??

Altering successional pathways by reducing ectomycorrhizal infection of willow and balsam poplar fine roots and reduce their ability to compete for nutrients with alder –also mycorrhizal but rarely browsed by snowshoe hare and moose


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Mycorrhizal dynamics under elevated CO2 and nitrogen fertilization in a warm temperate forest

Maria O. Garcia & Tatevik Ovasapyan & Mary Greas & Kathleen K. Treseder

Plant Soil (2008) 303:301–310, http://face.env.duke.edu/PDF/ps00-08.pdf

“In particular, we hypothesized that mycorrhizal fungi and … would become more prevalent under elevated CO2 ...

.. Overall, we observed a 14% increase in

ectomycorrhizal (ECM) root colonization under CO2 enrichment, which implies that elevated CO2 results in greater C investments in these fungi.”

DOI 10.1007/s11104-007-9509-9

Received: 16 August 2007 / Accepted: 29 November 2007 / Published online: 15 December 2007

# Springer Science + Business Media B.V. 2007


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Subtropical Forest fertilization in a warm temperate forest

Puerto Rico

Example


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6 Hurricanes during ~ 10 yr study: fertilization in a warm temperate forestSept 1989 – Hugo;early-mid Sept 1995 – Luis & Marilyn;Jul 1996 – Bertha;Sept 1996 -Hortense;Sept 1998 - Georges

Weather events keeps forests early successional

Hurricane Georges hits Puerto Rico on September 21, 1998. Image by Dennis Chesters, Marit Jentoft-Nilsen, Craig Mayhew, and Hal Pierce, Laboratory for Atmospheres, NASA Goddard Space Flight Center from data derived from NOAA GOES-8 satellite. Image from "http://rsd.gsfc.nasa.gov/rsd/images/Georges.html".


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Foliage decay < 6 months so pulse of nutrients available; however, foliage area takes several years to re-establish

Hurricane Hugo



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Drought 1994 mycorrhizas and fine roots???

Drought 1997

H. Hortense

H. Bertha

Drought 1996

H. Luis & Marilyn

Wood addition

Root growth increased with wood addition

Wood removal


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Some Benefits of Mycorrhizas mycorrhizas and fine roots???

  • Allow plant establishment on nutrient poor soils (mining reclamation, revegetation projects)

  • Increase plant size in short time period (forestry)

  • Reduce fertilizer requirements

  • Cut down production costs

  • Decrease fertilizer contamination of the environment


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Old growth Douglas-fir forests, Northern Spotted owl (NSO), Flying Squirrel feed on the mushrooms (mycorrhizas) that form specifically on Old Growth tree roots and preyed upon by NSO. Take one link out, ecosystem may not be as resilient

Photo courtesy Jerry Franklin


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Native plant roots: what goes on below the surface Flying Squirrel feed on the mushrooms (mycorrhizas) that form specifically on Old Growth tree roots and preyed upon by NSO.

http://www.laspilitas.com/advanced/advroots.htm


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“Mycorrhizal fungi allow the plant to withstand more stress

Healthy soil smell good! Encourage the good organisms in the soil.

Build a native garden right and the microorganisms are stable and happy. Along with the mycorrhizas are associated soil bacteria that are nearly as important. Encourage the good ones (that live in the sweet smelling garden or forest soil good gardeners know) and discourage the bad ones (that live in the soil that has no smell or smells like musty newspapers, sauerkraut, or has a sharp acrid smell ). Smelling soil is as old as farming and has been a very reliable technique. That's very unscientific but it has been consistently right.”

http://www.laspilitas.com/advanced/advroots.htm


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Why need to understand how roots and mycorrhizas interface with the ecosystem:

  • Roots/mycorrhizas research exist a black hole and difficult to study because can’t see them expect in wet tropics where roots crawl out of the ground and into tree canopies

  • Plants obligate relationships with mycorrhizas to survive In less weathered (low nutrient availability ) and highly weathered soils (low nutrient availability, higher toxic chemicals), older growth stages and late successional stages

  • Roots/mycorrhizas allow plants to adapt to their changing soil environment during succession and when soil chemical is altered by human land-use activities

  • Fertilizing forests with a limiting nutrient like N may increase total NPP but reduce fine roots/mycorrhizas. Total NPP increase is not real, just shift allocation of C from below- to aboveground

  • Increasing (during C enrichment of atmosphere) or decreasing carbohydrate production by plants (herbivory) will change amount of mycorrhizas found on roots


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