Environmental Reader by John Hamm

ECOLOGY awareness


Garlic Mustard…Coming Soon

It comes in early spring usually clustering along the shade lines of trees, distinguished by the 3" crown of tiny, white four-pedal flowers at the top of a straight slender 1-4' stem.   Its leaves emit a garlic smell when rubbed.   It's pervasive, invasive (30 east-west states/Canada) and persistent, because it lacks enemies or consumers, and protects its turf.   

Garlic mustard produces antifungal chemicals, that disrupt the healthy relationship between hardwoods and soil fungi.   Researchers noted that native trees suffered in the presence of garlic mustard.   Maple and other hardwood seedlings grew slower in soil infested with it.     

Hardwoods and many plants use arbuscular mycorrhizal fungi, which form a network of filaments throughout the soil; the fungi help plants take up nutrients and getting carbon in return. Garlic mustard does not need this relationship with the fungi.   Mycorrhizal fungi have learned to live with the native mustards over a long time, but haven't had time to adapt to the invasive garlic mustard.   It is killing off the fungi; changing forest ecology.   

What can you do? Identify it.   

Seeds can survive for more than 5 years. years.   Garlic mustard is biennial.  First year plants are low, olive green, kidney-shaped, which stay green through winter, so they will stand out with other plants having withered since fall.   In the second year's early spring, a rapidly growing shoot forms clusters of the tiny white flowers. Remove roots and all, early, before flowering and certainly before seeding.  Bag and dispose of seeded ones. 

Links for more info on garlic mustard:





  • Garlic mustard in flower
    Garlic mustard gone to seed
    First year plant and closeup of flower

    Good Friends
    (National Wildlife Federation Feb/Mar 2009)

    Some humans consider beavers pests, especially when the animal's dams flood property.  But for several species of migratory songbirds, the busy rodents are important allies.  A new study by the Wildlife Conservation Society finds that beaver dams create ponds and encourage the growth of streamside vegetation - all vital to the survival of migratory birds.  According to the study, songbird population became more abundant and diverse when beavers, which study co-author Steve Zack calls "essential ecosystem engineers" built more dams in local waterways. 

    check out the beavers on Chartiers Creek.  Look for whittled trees and beaver dams.  On canoe trips, you can often spot them swimming in the water.  


    Top 10 Myths of Tree Care
    (Suburban Gazette 3/22/06)

    1. Stake new trees
      Unstaked trees develop more roots, trunk taper; avoid trunk damage. 

    2. Trunk wrapping
      Ineffective for: bark temperature control, can worsen; insect barrier.

    3. Pruning new planting
      Unpruned trees establish better with the fullest crown of leaves for photosynthetic food production, root development; limit to damaged limbs and training.

    4. Remove branches with a flush cut
      Trees don't heal like people with similar tissue to tissue removed.  They generate 'woundwood' over the cut.  Flush cutting removes the 'branch collar' creating a larger wound than if the cut was beyond the collar.  Decay also has shorter distance to enter.

    5. Cut branches over 3" should be painted
      Cutting live branches over 3" risks more infection, but wound dressings do not inhibit decay, insect entry or speed healing, but actually slow wound closure.

    6. Top fast-growing trees
      Topping stimulates multiple shoots with weak attachments and makes decay easier.  Within 2-5 years, the tree regains former height and makes it more hazardous and ugly.  Alternatives are thinning, cabling, replacing.  Let them be natural. 

    7. Pruning in spring stresses trees
      Pruning can done anytime, but best is when dormant and worst is after spring leafing. 

    8. Roots mirror the top
      Taproots are rare in immature trees…even early ones go horizontal.  Roots can extend 2-3 times the spread of the crown, but within 3' of soil. 

    9. Trees require deep root fertilization
      Find most roots in the top 8" for absorbing nutrients. 

    10. Crown should be cut back with root loss
      Research supports un-pruned trees respond better than pruned, because the more leaves the better for producing the tree's food.

    Thriving Bald Eagles Run Short On Habitat
    (D'Vera Cohn, Wash Post/PG 4/21/06)

    Populations of bald eagles have grown ten times since the late 1970s in the Chesapeake, from a hundred pairs to a thousand, and are booming throughout the country.  It may be reaching some capacity going by signs of competing for habitat.  It remains to be seen if they will adapt to more urban landscape and/or get more protected waterfront.  Their recovery, from fewer than 500 pairs three decades ago to more than 7000 now, is credited to banning DDT, which thinned eggshells, and to expanded protection and habitat.  The Interior Department has proposed removing their endangered species listing.


    Birds Sing Songs for Various Reasons
    (Scott Shalaway PG 5/17/06)

    Birds "call" (vocalize) to convey information between members of their flock on location, food sources, social position, alarm, danger, aggression, annoyance, or other conversational items, just as humans do.  It's related to daily function.  'Song' is different, typically limited to the breeding season, but not always; usually by males, but not always, at least more subtle in females.  Males sing for two reasons: to establish and defend a territory ('keep out') and from many perches to broadcast and create illusion that area may be overrun by competing males; to attract females.  If singing threatens to divulge location to predators, birds simply stop talking and hide. 

    A Cat Call for Pet Owners
    (Scott Shalaway/PG)

    Free-roaming cats prey on many wildlife species, that would otherwise provide food for native predators such as hawks, owls, foxes, weasels and bobcats.  A 1997 poll showed only a third of the 90 million  pet cats live indoors.  The American Bird Conservancy says 60-100 million cats roam homelessly, killing one bird, mammal, frog or snake every week.  One study even found that declawed cats killed more.  Another interesting study presented a small live rat to six cats while eating.  All of them stopped eating, killed the rat, then resumed their regular meal.  

    Cat lovers counter that pets need to exercise outdoors to get fresh air.  Hogwash!  

    "They train me to perform.  Then when I try to show off what I really do best, everybody goes ballistic"

    Cats are domesticated.  They are at risk outdoors and suffer lower life expectancy from attacks by dogs, cats, raccoons, skunks, foxes, particularly coyotes or from infections, rabies, distemper.  Then there's abuse by other people, getting lost or stolen, getting fleas and ticks.  Vets and organizations always address the outdoor cat issue.  For those who insist on an outdoor experience, outdoors enclosures can work.  Keeping cats indoors is best for cats, owners, the neighborhood and the environment. 


    Worms at the Root
    (New York Times 3/7/06)

    Why you often find worms among long roots like dandelion?  Both dandelion roots and earthworms aerate the soil.  Roots make it easier for worms to plumb compacted soil.  When the roots die, worms can move even more freely and eat the roots too.  Dandelions by the way are not in competition with grass for nutrients, since they draw deeper than grass roots.  When the flowers and leaves decay above ground, they leave their nutrients for the grass.  Originally brought to America for medicinal and food use, dandelions are still often cultivated…their leaves for salad green and blooms for spring color and then wine.  You can use the whole plant.  The flowers also are a significant source of nectar and pollen for bees and other insects, including beneficial ladybugs, and small birds eat its seeds.  (So much for eliminating them from a monoculture lawn) 

    Worms . . . The Dark Side
    (NYT 3/15/07)

    Worms might be good for decomposing organic matter, aerating and churning nutrients into soil, but for shade plants and trees they are a growing menace.  Forests in the Northeast and Midwest have worms proliferating at such a rate that they are actually destroying the duff, the thick leaf litter that nourishes tree seedlings, prevents erosion and protects woodland plants from disease and insects.  Earthworms are not meant to be in a forest, which evolved without them.  Their decomposers are fungi, microflora and fauna, which release nutrients very slowly.  

    Worms arrived with the colonists in two varieties: nightcrawlers, which burrow deeply, pulling leaf litter with it, and Amynthas hawayanus, which is a surface dweller. 

    Worms roto-till and change the chemistry of the soil as their gizzards emit calcium carbonate, known as lime, making soil alkaline.  It is good for corn, but not for azaleas and oaks.  

    Worms break down organic material so quickly that nutrient overload injures plants, runs off into streams and invites invasives - stiltgrass and garlic mustard, which thrive on heavy nitrogen.  This thins the forest, erodes open spaces, and in shifting the microbial community from fungal to bacterial, disturbs the perennial spring ephermerals like trillium, mayflowers and trout lilies.  

    How to test for too many worms?  In a 3 foot square sink big coffee cans when the soil is soaked.  Apply hot Chinese mustard, 2 cups/10.5 quarts water, to bring the worms up.  If more than 5 worms, you have a problem.  Killing them is illegal because the Dept of Agriculture lists them as beneficial, so control by not feeding them with wood chips or compost in paths, leave grass clippings next to the woods, and don't toss those unused fishing worms near woods…put them in an open garden.

    Water Quality Indicators, It's a Bug's Job 
    Joan Wilson/The Sylvanian (Sierra Club, Mar-Jun 06)

    Bugs tell us a lot about water quality. They include macroinvertebrates (macro = seen by naked eye . . . invertebrates = no backbone), such as dragonflies, mayflies, stoneflies, crayfish, water beetles, snails, leeches and black flies.  They are indicators of water quality.  You worry when you don't find them.  They spend one to four years as larvae or nymphs fully submerged in water, then shed exoskeletons and emerge as winged adults.  Their adult lives are only a fraction of their childhood, a day to a few months, spent mating to recycle themselves.  So next time you see a bug that looks like a giant mosquito, don't squash it.  It's an adult crane fly and it's telling you that the water is fine.  Feel happy when you see bugs. 

    Border War
    (George Ball/New York Times 3/20/06)

    The horticultural world is having its own debate over immigration with environmentalists warning about exotics invading our gardens and spreading on a mission to collapse the ecosystem.  They beckon us into a perfect natural world, with gardens populated exclusively by native plants, which never really did exist and never will.  Many plants considered native, like sycamores, magnolias and cinnamon, arrived from other continents, just as we did.  Should we eat no onions, apples or lemons or see no tulips or roses - exotics from Europe, or enjoy no peppers, tomatoes, beans, squash, sunflowers, potatoes or corn - all from other Americas.  How about petunias, impatiens, begonias, yarrow, Queen Anne's lace, chicory and hollyhocks - not one of them native.  Is the argument against destructive invasives the same as controlling human immigration?  It's not taking the side of truly destructive invasives.  No gardener would. 

    How Does Fertilizer Work? 

    Confused about how roots and leaves produce food for plants?  Roots absorb nutrients…leaves breathe.  Just as we eat to get certain nutrients and breathe to get others for chemicals we need.  Plants produce their food by photosynthesis, 'inhaling' our exhaled carbon dioxide to give us oxygen and sequester the carbon using the sunlight in a reaction that gives them energy.  To make this food, they require nine chemicals: carbon, hydrogen, oxygen, phosphorus, potassium, nitrogen, sulfur, calcium and magnesium.  Air (CO2) and water (H2O) provide most of the carbon, hydrogen, and oxygen that they need for growth.  The others come naturally from soil in decaying plants and animals and dissolved minerals.  But when we harvest plants, they are removed before they die and decay, so nutrients are not replaced, especially nitrogen, phosphorus, and potassium.   This is why fertilizers contain '5-10-5'

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    19 Mar 2009
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