Tuesday, May 25, 2010

Cogongrass - Invasive Weed

University of Georgia Thomas County Ag Agent and Warnell School of Forestry specialist discuss cogongrass.
Visit www.thomascountyextension.com or www.cogongrass.org for more information.
Key Identification Features of Cogongrass
Flower/Seed head

Cylindrical in shape
2-8 inches in length (total flower or seed head)
Silvery white in color
Light fluffy dandelion-like seeds
Blooms from late March to mid June (flower timing depends somewhat on local climate)

Blades up to 6 feet long
About 1 inch wide
Whitish, prominent midrib, that is often off center
Margins finely serrate
Some leaves are very erect, but some may droop or lie flat
Often light yellowish-green in color
Could have a reddish cast in fall/winter or brown after frost or freeze
Plant Base

No apparent stem
Leaves appear to arise directly from or close to the ground
Overlapping sheaths give a rounded appearance to the plant base
All vegetation doesn't arise from one dense clump, instead the plants are more spread out
Light-green to yellowish in color, or could be reddish
Often a lot of thatch around base
Leaf collar/Ligule

Ligule is a thin-fringed membrane
Leaf sheaths overlapping, giving the plant a round appearance
Hairy (the ligule is the most hairy part of the plant, the plant base may also be somewhat hairy)

Dense mat
Many sharp points
Covered in flaky scales
Bright white under scales
Strongly segmented
Whole Plant

Densely growing patches
Tall grass (up to six feet, averaging 3-4 feet)
Circular infestations
Plants often turn brown in winter (at least partially, but may depend on local climate)

Saturday, May 8, 2010

Slime Mold in the yard?

I have seen and had calls on slime mold in lawns this week. With the high humidity we have had this week it has helped create a good environment to host this. Slime mold will show up in patches on your turfgrass and look like black spots in the yard. They are pin-head sized fruiting bodies on the blades of grass and usually in a irregular circle. It will not kill your grass but rather weaken the health.

Large numbers of pinhead-sized fruiting bodies may suddenly appear on grass blades and stems in circular to irregular patches 1-30 inches in diameter. Affected patches of grass do not normally die or turn yellow and signs of the fungi usually disappear within 1 to 2 weeks. These fungi normally reproduce in the same location each year. The fungi are not parasitic, but they may shade the individual grass leaves to the extent that leaves may be weakened by inefficient photosynthesis.

Conditions Favoring Disease:
Slime molds are favored by cool temperatures and continuous high humidity. An abundance of thatch favors slime molds by providing food directly in the form of organic matter.

Management Tips:
# Remove slime mold by mowing.
# Remove using gardening tool or high pressure stream of water.

For more info visit University of Georgia Thomas County Extension Office or our

Friday, May 7, 2010

Identified Benefits of Community Trees and Forests

By Kim Coder, Professor, Silvics/Ecology, Warnell School of Forest Resources, The University of Georgia

Community trees and forests are valuable. To the 75% of the United States population that now live in urban and suburban areas, trees provide many goods and services. Values are realized by the people that own the trees, by people nearby, and by society in general. People plant, maintain, conserve, and covet trees because of the values and benefits generated.

Tree benefits can be listed in many forms. The bottom-line is humans derive not a single-user value from community trees and forests, but a multi-product / multi-value benefit. Some of these benefits stem from components and attributes of a single tree, while other benefits are derived from groups of trees functioning together. What is the value of these multiple benefits? A 1985 study concluded that the annual ecological contribution of an average community tree was $270.

Values, functions, goods and services produced by community trees and forests can be evaluated for economic and quality of life components. While quality of life values are difficult to quantify, some of the economic values can suggest current and future negative or positive cash flows. In assessing changes in dollar values, concerns for tree evaluation are most prevalent within: risk management costs (liability and safety); value-added / capital increases to tree values; appreciation of tree and forest assets; maintenance costs of tree and forest assets; and, level of management effectiveness and efficiency (total quality management of community trees and forests -- TTQM).

Below are listed a selected series of goods, services, and benefits community trees across the nation and forests provide. These bullets of information are taken from a diversity of individual research projects and, as such, are individually meaningless except under similar conditions. These items together do suggest trends and concepts of value.
Environmental Benefits
Temperature and Energy Use

* Community heat islands (3 to 10°F warmer than surrounding countryside) exist because of decreased wind, increased high density surfaces, and heat generated from human associated activities, all of which requires addition energy expenditures to off-set. Trees can be successfully used to mitigate heat islands.
* Trees reduce temperatures by shading surfaces, dissipating heat through evaporation, and controlling air movement responsible for advected heat.


* 20°F lower temperature on a site from trees.
* 35°F lower hard surface temperature under tree shade than in full summer sun.
* 27% decrease in summer cooling costs with trees.
* 75% cooling savings under deciduous trees.
* 50% cooling energy savings with trees. (1980) 20°F lower room temperatures in uninsulated house during summer from tree shade.
* $242 savings per home per year in cooling costs with trees.
* West wall shading is the best cooling cost savings component.
* South side shade trees saved $38 per home per year.
* 10% energy savings when cooling equipment shaded (no air flow reduction).
* 12% increase in heating costs under evergreen canopy
* 15% heating energy savings with trees. (1980)
* 5% higher winter energy use under tree shade
* $122 increase in annual heating costs with south and east wall shading off-set by $155 annual savings in cooling costs.
* Crown form and amount of light passing through a tree can be adjusted by crown reduction and thinning.
* Shade areas generated by trees are equivalent to $2.75 per square foot of value (1975 dollars).

Wind Control

* 50% wind speed reduction by shade trees yielded 7% reduction in heating energy in winter.
* 8% reduction in heating energy in home from deciduous trees although solar gain was reduced.
* $50 per year decrease in heating costs from tree control of wind.
* Trees block winter winds and reduces "chill factor."
* Trees can reduce cold air infiltration and exchange in a house by maintaining a reduced wind or still area.
* Trees can be planted to funnel or baffle wind away from areas -- both vertical and horizontal concentrations of foliage can modify air movement patterns.
* Blockage of cooling breezes by trees increased by $75 per year cooling energy use.

Active Evaporation

* 65% of heat generated in full sunlight on a tree is dissipated by active evaporation from leaf surfaces.
* 17% reduction in building cooling by active evaporation by trees.
* One acre of vegetation transpires as much as 1600 gallons of water on sunny summer days.
* 30% vegetation coverage will provide 66% as much cooling to a site as full vegetation coverage.
* A one-fifth acre house lot with 30% vegetation cover dissipates as much heat as running two central air conditioners.

Air Quality

Trees help control pollution through acting as biological and physical nets, but they are also poisoned by pollution.
Oxygen Production
One acre of trees generates enough oxygen each day for 18 people.
Pollution Reduction

* Community forests cleanse the air by intercepting and slowing particulate materials causing them to fall out, and by absorbing pollutant gases on surfaces and through uptake onto inner leaf surfaces.
* Pollutants partially controlled by trees include nitrogen oxides, sulfur dioxides, carbon monoxide, carbon dioxide (required for normal tree function), ozone, and small particulates less than 10 microns in size.
* Removal of particulates amounts to 9% across deciduous trees and 13% across evergreen trees.
* Pollen and mold spore, are part of a living system and produced in tree areas, but trees also sweep out of the air large amounts of these particulates.
* In one urban park (212 ha), tree cover was found to remove daily 48 lbs particulates, 9 lbs nitrogen dioxide, 6 lbs sulfur dioxide, and ½ lbs carbon monoxide. ($136 per day value based upon pollution control technology).
* 60% reduction in street level particulates with trees.
* One sugar maple (one foot in diameter) along a roadway removes in one growing season 60 mg cadmium, 140 mg chromium, 820 mg nickel and 5200mg lead from the environment.
* Interiorscape trees can remove organic pollutants from indoor air

Carbon Dioxide Reduction

* Approximately 800 million tons of carbon are currently stored in US community forests with 6.5 million tons per year increase in storage ($22 billion equivalent in control costs).
* A single tree stores on average 13 pounds of carbon annually.
* A community forest can store 2.6 tons of carbon per acre per year.


* Development increases hard, non-evaporative surfaces and decreases soil infiltration -- increases water volume, velocity and pollution load of run-off -- increases water quality losses, erosion, and flooding.
* Community tree and forest cover intercepts, slows, evaporates, and stores water through normal tree functions, soil surface protection, and soil area of biologically active surfaces.

Water Run-Off

* 7% of winter precipitation intercepted and evaporated by deciduous trees.
* 22% of winter precipitation intercepted and evaporated by evergreen trees.
* 18% of growing season precipitation intercepted and evaporated by all trees.
* For every 5% of tree cover area added to a community, run-off is reduced by approximately 2%
* 7% volume reduction in six-hour storm flow by community tree canopies.
* 17% (11.3 million gallons) run-off reduction from a twelve-hour storm with tree canopies in a medium-sized city ($226,000 avoided run-off water control costs).

Water Quality / Erosion

* Community trees and forests act as filters removing nutrients and sediments while increasing ground water recharge.
* 37,500 tons of sediment per square mile per year comes off of developing and developed landscapes -- trees could reduce this value by 95% ($336,000 annual control cost savings with trees).
* 47% of surface pollutants are removed in first 15 minutes of storm -- this includes pesticides, fertilizers, and biologically derived materials and litter.
* 10,886 tons of soil saved annually with tree cover in a medium-sized city.

Noise Abatement

* 7db noise reduction per 100 feet of forest due to trees by reflecting and absorbing sound energy (solid walls decrease sound by 15 db)
* Trees provide "white noise," the noise of the leaves and branches in the wind and associated natural sounds, that masks other man-caused sounds.

Glare Reduction

* Trees help control light scattering, light intensity, and modifies predominant wavelengths on a site.
* Trees block and reflect sunlight and artificial lights to minimize eye strain and frame lighted areas where needed for architectural emphasis, safety, and visibility.

Animal Habitats

* Wildlife values are derived from aesthetic, recreation, and educational uses.
* Lowest bird diversity is in areas of mowed lawn -- highest in area of large trees, greatest tree diversity, and brushy areas.
* Highest native bird populations in areas of highest native plant populations.
* Highly variable species attributes and needs must be identified to clearly determine tree and community tree and forest influences.
* Trees are living systems that interact with other living things in sharing and recycling resources -- as such, trees are living centers where living thing congregate and are concentrated.

Economic / Social / Psychological Benefits
Economic Stability

* Community trees and forests provide a business generating, and a positive real estate transaction appearance and atmosphere.
* Increased property values, increased tax revenues, increased income levels, faster real estate sales turn-over rates, shorter unoccupied periods, increased recruitment of buyers, increased jobs, increased worker productivity, and increased number of customers have all been linked to tree and landscape presence.
* Tree amenity values are a part of real estate prices.

Property Values -- Real Estate Comparisons

* Clearing unimproved lots is costlier than properly preserving trees.
* 6% ($2,686) total property value in tree cover.
* $9,500 higher sale values due to tree cover.
* 4% higher sale value with five trees in the front yard -- $257 per pine, $333 per hardwood, $336 per large tree, and $0 per small tree.
* $2,675 increase in sale price when adjacent to tree green space as compared to similar houses 200 feet away from green space.
* $4.20 decrease in residential sales price for every foot away from green space.
* 27% increase in development land values with trees present.
* 19% increase in property values with trees. (1971 & 1983)
* 27% increase in appraised land values with trees. (1973)
* 9% increase in property value for a single tree. (1981)

Property Values -- Tree Value Formula (CTLA 8th edition)

* Values of single trees in perfect conditions and locations in the Southeast range up to $100,000.
* $100 million is the value of community trees and forests in Savannah, GA
* $386 million is the value of community trees and forests in Oakland, CA (59% of this value is in residential trees).

Product Production

* Community trees and forests generate many traditional products for the cash and barter marketplace that include lumber, pulpwood, hobbyist woods, fruits, nuts, mulch, composting materials, firewood, and nursery plants.

Aesthetic Preferences

* Conifers, large trees, low tree densities, closed tree canopies, distant views, and native species all had positive values in scenic quality.
* Large old street trees were found to be the most important indicator of attractiveness in a community.
* Increasing tree density (optimal 53 trees per acre) and decreasing understory density are associated with positive perceptions.
* Increasing levels of tree density can initiate feelings of fear and endangerment -- an optimum number of trees allows for visual distances and openness while blocking or screening developed areas.
* Species diversity as a distinct quantity was not important to scenic quality.

Visual Screening

* The most common use of trees for utilitarian purposes is screening undesirable and disturbing sight lines.
* Tree crown management and tree species selection can help completely or partially block vision lines that show human density problems, development activities, or commercial / residential interfaces.


* Contact with nature in many communities may be limited to local trees and green areas (for noticing natural cycles, seasons, sounds, animals, plants, etc.) Trees are critical in this context.
* $1.60 is the willing additional payment per visit for use of a tree covered park compared with a maintained lawn area.


* Stressed individuals looking at slides of nature had reduced negative emotions and greater positive feelings than when looking at urban scenes without trees and other plants.
* Stressed individuals recuperate faster when viewing tree filled images.
* Hospital patients with natural views from their rooms had significantly shorter stays, less pain medicine required, and fewer post-operative complications.
* Psychiatric patients are more sociable and less stressed when green things are visible and immediately present.
* Prison inmates sought less health care if they had a view of a green landscape.

Human Social Interactions

* People feel more comfortable and at ease when in shaded, open areas of trees as compared to areas of hardscapes and non-living things.
* People's preferences for locating areas of social interactions in calming, beautiful, and nature-dominated areas revolve around the presence of community trees and forests.
* Trees and people are psychologically linked by culture, socialization, and coadaptive history.

Reference for most of this material: Literature Review for the QUANTITREE computer program -- "Quantifiable Urban Forest Benefits and Costs; Current Findings and Future Research." In a white paper entitled Consolidating and Communicating Urban Forest Benefits. Davey Resource Group, Kent, OH. 1993. pp.25.

For more information visit University of Georgia Thomas County Extension
webpage or office.

Thursday, May 6, 2010

Care of Young Shade and Street Trees

Young trees in the landscape, less than three to five years old, require special care to insure establishment and rapid growth. Proper early care helps young trees develop an adequate root system and a strong supportive branch structure. The time and expense invested to train a young tree is much less than treating problems as the tree matures.

Young trees may require staking, wrapping and corrective pruning. Proper mulching and control of competition can speed growth. In addition, trees require plenty of available water and essential elements for good growth. Young trees need protection from construction activities, lawn mowers and weed eaters, vandals, and pests.


Young street and shade trees require proper pruning. Early pruning improves overall structure and corrects branch defects. Early pruning eliminates problems which become severe in middle and old age. Pruning shade and street trees develops and maintains a central dominant leader. Double or co-dominant leaders (forks) should be removed. Select the main leader early and maintain strong side branches. These side branches become the major limbs supporting the weight of the tree later in life. Remove dead, diseased and broken branches. Prune out deformed and crossing branches.

Many side branches should occur singly (alternately) on shade and street trees. However, trees such as ash and maple frequently have major branches occuring in pairs across the main stem. They can be pruned alternately up to 12 to 18 feet. Select and maintain major side branches spaced 24 to 36 inches apart on alternating sides of the stem. Also, select branches with wide angles of attachment, 60 to 90 degrees between the trunk and the branch. remove all waterspouts and basal sprouts.


Most established young trees can stand alone against wind and not be staked. Young trees with excessively long new shoots or those exposed to windy sites may require staking to remain upright. Stake young trees that are susceptible to blowing over. Anchorage staking holds the roots or root ball stationary until roots become anchored. Use two or three short stakes for anchorage. Extend stakes 12 to 18 inches above the ground. Loop one tie strap loosely around each stake and around the tree trunk. Low attachment prevents root ball dislodgement yet allows the top to move. Staking is temporary. Be sure to check ties frequently.

Support staking aids trees whose trunks are not strong enough to stand upright or fail to return upright. Support the top about six inches above the lowest level at which the trunk can be held and remain upright. This allows top flexibility while providing support. Support the trunk so it can flex without rubbing against the stakes or ties. This must not damage tender bark or girdle the expanding trunk. Support staking holds the tree upright until it can stand alone.


Newly-planted thin bark trees such as red maple or cherries may benefit from wrapping the trunks at planting. Thin barked trees planted on hot sites are very susceptible to sunscald. Commercial tree wraps or plastic tree guards will protect young trees. Spring planted trees can be susceptible to sunburn. The high temperatures from the summer sun may kill the cambium. Tree wraps insulate the cambium.

Young trees may require protection from sunscald. Sunscald occurs when the cambium of thin barked trees heats up during sunny fall or winter days. Colder temperatures that follow warm periods kill cambium cells in the trunk. Long verticle scars run down the trunk from near the lower most branches to the soil line. Injury usually occurs on the southwest side of the trunk. Thin bark maples and cherries, 4 to 5 inches in diameter, may require wrapping in fall to prevent sunscald.

Tree wraps also protect young trees from girdling by rodents. Start at the base of the trunk and wrap up to the lowermost limbs. Overlap each layer one-half inch. Wrap in the fall and leave the tree wrap on throughout the winter and early spring. Tree wrap is temporary and no longer needed once the tree develops corky bark.


Young trees growing in turf areas that are regularly fertilized do not usually require additional fertilization. Trees showing poor growth require a soil test to determine if essential elements are in short supply. When nitrogen is required, fertilize trees by applying 3 pounds of nitrogen per 1000 square feet of area per year. Make two or three applications, one each in April, June and October(optional) at 1 pound of nitrogen per 1000 square feet. Water each site after applying the fertilizer. Fertilizing trees with a turfgrass or groundcover understory requires multiple applications at light rates to avoid injury to the turfgrass or groundcover plants.


Mulches aid in the establishment and growth of young trees. They conserve moisture by reducing evaporation from the soil surface. Mulches reduce erosion and water run-off. Mulches reduce competition and compaction. Mulches can effectively reduce summer soil temperatures to create a more favorable root environment. Organic mulches break down and add essential elements to the soil. Do not mulch wet sites, as mulch materials keep soils overly moist by retaining too much soil water.

To improve growth, mulch young trees out beyond the edge of the canopy. Use three to four inches of an organic mulch. Mulches eliminate the need for groundcovers and turfgrasses beneath young trees, thereby reducing competition for essential elements and moisture. Mulching prevents serious injuries to young tree trunks because there is no need to mow or use string-trimmers beneath trees.

Appropriate mulches include pine bark, pine straw and wood chips. Organic mulches more effectively insulate the soil than inorganic or rock mulches. Pull all mulches back from the trunk four to six inches to prevent diseases from invading the trunk. Rodents may live and burrow in loose mulches, so be alert for these pests.

Improving Growth

You can improve young tree growth by following a few basic cultural practices. First, eliminate competition from turfgrasses and groundcovers underneath young trees. Second but very important, mulch beneath the canopy and out beyond the edge of the foliage to improve the root zone environment. Third, surface apply fertilizers directly to the mulched area. Fourth, water during periods of drought. Fifth, keep lawn mowers and string-trimmers away from tree trunks. These steps will improve growth, even on slow-growing trees.

For more information visit the University of Georgia Thomas County Extension webpage or drop by the office.