Sunday 18 November 2012

Lessons from Sandy and Others

If you survived Sandy, Irene, Lee, or Ernesto, on TV or in real life you may have learned a few lessons of your own.
As a person who cares for trees daily, both in the practical and abstract sense, it was a tragic tutorial that I will not forget. I have to date not experienced the level of destruction to property nor do I expect to again. Personally we had a large oak tree slam an 80 year old masonry fire place into a pile of rubble. It was thankfully; a ways from the house and it can be rebuilt. Many people were not so lucky. I have also seen the ensuing panic that has no doubt resulted in many unnecessary tree removals in the name of safety. 
All trees are at risk of failing, I want to say that right up front. As long as there is gravity, wind and the weather this will continue to be a possibility.
We live with risk every day and the key is to look at it objectively and try to minimize it where possible.
The key to mitigating risk is knowledge and preparation.                  
Inadvertently I participated in an experiment that yielded surprisingly predictable results. A year and several months ago on October 29th 2011, we experienced a heavy snow and ice storm that caused tremendous numbers of broken limbs. Over the next year, in several different operations, we removed the broken branches, reduced the numbers of branches, and cabled and supported all of the trees except one. That tree had a large bracket fungus halfway up its canopy where the two main trunks split into co-dominant leaders. Based on my observations that tree would have to eventually be removed.
While I was waiting for the appropriate time to remove the tree, Super Storm Sandy arrived and her 85 mph winds howled through the trees and across the rain soaked saturated soils. Not one of the trees that we had reduced the canopy, pruned broken branches from or installed preventative cables in failed. The trees that were pruned were of higher priority as they would have certainly caused damage to the house had they fallen on it.
The one tree we ignored popped out of the ground and fell like a gavel on our masonry fireplace, across the fence and into the garden.
There is a conceptual equation for accessing the potential risk presented by a tree in a landscape.
It is as follows: Risk = Potential x Environment x Target.
Risk increases if you have a potential for failure like, a weak crotch, overextended limb or cavity. If you have an environment that increases the possibility of failure like a newly exposed face or area that was previously sheltered, a wet site with shallow roots, or a change in grade due to construction. All of this means nothing if you don’t have a target like a structure or even children playground equipment. All of these elements are not created equally and it takes a trained professional to understand all the potential problems that create and reduce risk. ISA Certified Arborists have continuous training that helps them to keep up with the latest tree risk information.
Have you contacted your Arborist to review your changing landscape?

Thursday 18 October 2012

Defending the Delicious

If you’re a fan of plants, you may not be a fan of deer eating them.

I enjoy deer watching... from a distance that is. A good fence makes great neighbors and it can certainly help a great garden.  however If you are like many of us who don't want the expense or incarcerated look and feel of living inside a fenced compound you do have options.

The best defense is a great offense and deer are complex creatures of habit. When they feel safe and find delicious food, they will include your trees shrubs and greenery on their daily wanderings. As with any Unwelcome guest making them feel more than a little uncomfortable speeds their departure and reduces the chance they will return.

Deer have a varied menu of trees shrubs and plants the will eat and in a pinch this grows to include normally unpalatable items like spruce, tree bark and wood.

These are listed in order of desperation and are not exclusive; they will eat whatever is available to survive.

They generally prefer lush energy rich plants like hosta or evergreens with softer needles like taxus or hemlock.

You can just plant trees and shrubs that are deer resistant but that leads to a dull landscape.

The best defense short of an 8 foot fence is a multi-pronged assault on all the deer's senses. Smell, taste and sound are three primary senses used by deer to navigate their way in the landscape. Sight, and particularly motion are also factors that influence a deer by making them feel less at ease. 

Change and motion in the landscape creates feelings   of unease and the potential for predators to sneak up on them well feeding makes the deer less likely to linger and sample your garden. 

There are many taste and smell deterrents available that use a variety of ingredients including blood, urine, garlic, rotten eggs and a variety of mouth burning spices and peppers. They all work to some extent, but deer, being creatures of habit will eventually  adjust  to the taste and smell and eat your trees and shrubs in spite of your repeated spraying. A change will do you good! Change up your spray by using a variety of different sprays. This reduces habituation and acts on a variety of senses. Deer don't like this unpleasant change. 

Blocking trails, and reducing bedding and birthing areas in your immediate hinterland will also take the game to a new level. Keep in mind that other people use trails before you pile brush or put log mats across them.  Placing a few brushy branch piles on sites that deer lay down to rest on is a sure way to keep them on the move,

If a doe does give birth near your garden the feeding pressure will be increased as the new mother will not travel far to feed while the fawns are small. She will eat a much greater variety of non-preferred foods while she nurses and stays close to the birthing area. 

Encouraging you dog to mark its territory at the boundary of your garden is also an effective deterrent. Motion sensing sprinklers, lights and other high tech gadgets are also effective as part of an overall program of wholesale unfriendliness.

Sound deterrents are useful as they not only startle the deer but create a sense of unease at the lack of ability to hear the approach of predators. 

As with all deterrents sound devices must change and have variability to prevent them from becoming routine and ignored. All this can seem like a lot of work and it can be, you have to keep in mind that your garden has to be peacefully and accessible. Thankfully our senses are much less keen than the average deer so we don't smell the repellents or hear the ultrasonic devices. There are companies that will provide a regular deer repellent spray program and this can be very effective as it takes the burden of scheduling off the home owners. Most of these programs change their formulas periodically to keep ahead of the deer. There are also companies that provide a dedicated deer deterrent program to take the entire process to a higher level while allowing you to plant what you want. 

ISA certified arborists are aware of what trees and shrubs are deer resistant in your landscape. Contact your land ISA Certified arborist to discuss your options for limiting deer damage on your landscape.

Tuesday 18 September 2012

New Rust in Town

                                 photo TCC

For the Bradford pear the long reign as the most trouble free tree may have come to an end. Recent laboratory confirmed cases of Pear Trellis Rust  Gymnosporangium sabinae   have been located in the North Eastern United States . While it has been present in Southern Ontario since 2007 and  is a common disease in the Pacific North East and Europe it has not been discovered beyond those areas. Pears, up to this point, have been free from most pests and had only their poor structure to cause problems in the landscape.  

Like most rusts, Pear Trellis Rust requires two distinct hosts at different times of the year. The summer host, the pear, is the most disfigured by the rust and may become completely defoliated if the outbreak is severe. Repeated unchecked out breaks could result in die back and mortality. The winter host, the juniper, is much less severely affected. The disease over winters as a gall on the juniper erupting in the spring with bright orange gelatinous fruiting structures called telia. These structures produce spores that are blow in the wind to the nearest pear. Under ideal conditions these can travel up to four miles.  The effect on landscape trees is dramatic. After the initial infection causing reddish orange blotches on the leaves the leaves turn brown they will fall from the tree throughout the growing season. On fruit trees it will damage a crop in short order. While the life-cycle of this disease is complicated, its unsightly effect on pears is simply awful.
All pears appear to be susceptible to varying degrees. Cultural controls like removing junipers from the area are not realistic given the close proximity of the two hosts in a typical landscape. Even if you were able to remove your junipers the possibility of there not being one in the area to act as a secondary host is remote. As this is a newly discovered disease treatment plans are still in the developmental stage and no fungicides are currently labeled to control this disease. One suspects that in time a treatment regime similar to apple rust will emerge and prove effective in controlling this new found nemesis of pears.

Take the time to contact your ISA Certified Arborist today and have your pears accessed for the potential impact of Pear Trellis Rust. Panic is pointless, preparation is priceless.

Saturday 18 August 2012

Emerald Ash Borer Update 2012

   photo USDA                                                                     

Recent information has confirmed that Emerald Ash Borer has been found in Northern Dutchess County in South Eastern New York. Though not unexpected, it is a milestone to have confirmed its presence this side of the Hudson River.
Do you have a plan in place to protect your valuable Ash trees? Treating your Ash trees before this bug arrives has proven effective in protecting Ash trees from this deadly pest.
Emerald Ash Borer (Agrilus planipennis) was discovered in the Detroit region in 2002 but was likely established in that area in the mid 1990's. This small brilliantly green insect is from China, where it is a minor forest insect living on weakened Ash trees in its native forests. American Ash trees have no natural resistance and are excellent hosts to this pest. Once infested with this pest Ash trees decline and eventually die in 2 to 3 years. Small or stressed trees may die in one season. One mode of transport this beetle shares with other destructive pests is its ability to spread by hitchhiking on firewood.  Quarantines prohibiting the movement of firewood and raw wood products are in place or will be in place in many areas by years end. Efforts to eradicate the pest have been largely unsuccessful, leading one official to describe it as “cutting a hole in a doughnut". The beetles have often spread beyond the site of initial infestation by the time they are detected and treated.  Efforts are taking place to look for naturally resistant selections of Ash as well as locate natural predators that may reduce Emerald Ash Borer's destructive abilities. What can you as a home owner do to be prepared for this pest? If it has been detected in your area you will need to protect Ash trees you want to preserve.
First you will need to assess if you have Ash trees on your property and what the appropriate action you should take. If you have Ash trees and want to protect them, you should maintain the vigor of those trees with appropriate cultural measures. These may include fertilization, root stimulants and mulching. Once EAB is close to your area, there are proven systemic treatments that can prevent infestation by EAB. Preparation and prevention are your best defenses against Emerald Ash Borer damage. The chart below estimates the risk to your ash trees posed by EAB and can be described as follows:

0-5 miles from a known EAB site-                  Extreme Risk,
5-10 miles from an EAB site                           High Risk,
10 miles and greater from an EAB site            Elevated Risk.

If you are in an area that is at elevated risk you should be developing a plan with the help of your ISA Certified Arborist. Take the time to contact your ISA Certified Arborist today and have your property accessed for the potential impact of Emerald Ash Borer. Panic is pointless, preparation is priceless.

Saturday 14 July 2012

Cedar Apple Rust

                                                                               PHOTO TCC

Cedar-Apple Rust, caused by the fungal disease, Gymnosporangium juniperi-virginianae is another serious and disfiguring disease of ornamental and fruit apples. Rust fungi are evolved complex organisms that require two hosts to complete their life cycle.

The first host of this disease is Eastern red cedar, Juniperus virginiana,where the rust forms ball like structures with fungal telial horns that forcibly eject the spores that spread the disease to apples. Although these bright orange horned goo balls are quite alarming they are usually not noticed on the juniper or mistaken for fruit or cones. Once the spores from the juniper travel to the leaves of apples the real unsightly damage occurs. 
On apples the spores germinate and after a week or two cause orange pustules on the leaves of susceptible apples. Rainy wet weather in the spring is ideal for the germination on junipers and the spread and infection to apples.
Once in the apple leaf, given a short period of wet weather, the leaf lesions form fruiting structures in mid to late summer and re-infect the juniper host where the disease over winters. 
Cultural control, includes removal of junipers in the vicinity of apples as well as planting disease resistant varieties of apples. Avoiding mass plantings of apples and junipers in landscapes reduces the amount of disease inoculum and the potential for severe outbreaks.
There are a number of fungicides that are labeled for control of Cedar-Apple Rust. Typically they require several applications starting at bud break and continuing every two weeks to get suitable control. Fungicides may also be applied to junipers in mid to late summer to reduce the back transmission from the apples to the junipers.

Your I.S.A. Certified Arborist is up to date on the latest research on Cedar Apple Rust and can help preserve your apple trees.

Monday 18 June 2012

Scabs on Your Apple

                                          photo bwg

Apple scab, caused by the fungal disease, Venturia inaequalis is one of the most serious and disfiguring diseases of ornamental and fruit apples. Although the name implies it is limited to apples, this disease can be found on many members of the rose family. The hosts can include apples, hawthorns, fire thorns, cotoneasters, and pears.

The symptoms of this disease are typically olive brown lesions on the leaves and sometimes on new succulent shoots. The scabs are indistinct at the margins and if the infection is severe they may coalesce into larger patches. The patchy lesions can be found on flowers, fruit, leaves and twigs. The tree responds to this infection by prematurely dropping infected leaves.  Repeated severe infections can cause die back after several years.

The disease overwinters in dropped leaves and affected twigs remaining on the tree. Wet spring conditions spread spores and allow them to germinate on the leaves, initiating new infections. The warmer the temperature, the shorter the amount of time it takes to initiate and infection. The peak period of infection occurs when the trees are starting to flower and continues until full bloom. Secondary infections will occur throughout the spring and summer when conditions are wet for long periods of time.

Some cultural control, including disposal of diseased leaves and twigs away from infected trees as well as the removal of all leaves in the fall will help to reduce the intensity of future infections. Planting disease resistant varieties and avoiding mass plantings also reduce the amount of disease inoculum and the potential for sever outbreaks.

There are a number of broad spectrum fungicides that are labeled for control of apple scab. Typically they require several applications starting at bud break and continuing every two weeks to get suitable control.

Your I.S.A. Certified Arborist is up to date on the latest research and can help preserve your apple trees.