Trees and Turf

People seem to believe that spruce and conifer trees are acidic. When the pine needles fall to the ground below them acidifying the soil under the tree killing the grass. But this isn’t true, the grass below a pine tree dies because of lack of sunlight and water. The cone like spread of a pine tree allows rain fall to drain along the needles. There is no real way to cure this issue, it is not recommended to prune up the lower branches of your spruce. This is because the tree can get sunscald the tree will also become unstable. If there is a prior issue in the tree then this could weaken the tree further. 

You can help to make your yard or landscape more appealing by removing the turf around trees and installing a mulch bed. This will help to hold moisture near the root zone giving you a happier tree as well as ridding yourself of the dead turf. 

Trees and turf are often planted together in the landscape as well as on golf courses. Trees and turf grass roots have a different root system from one and another. Trees start with having a tap root but that quickly hits a space in the soil where it can no longer grow down wards. This cause the roots to grow more lateral and near the surface.

When people are watering for both of these they will water for the turfs needs. This is because people want a lush green lawn for good play or just ascetic appeal. But when people are watering for turf the tree roots will grow in the same space. This is because tree roots will only grow in a space that has air and nutrients. If people are watering for turf grass then the tree roots will grow in the same area as turf grass. The trees will sometimes breach the surface of the turf. This hurts the mowing equipment and causes issues for game play. 

This not only reduces the appeal of your lawns but your trees also suffer as a result. Tree roots are in constantly competing for nutrients and water. It is best to plant trees in groups and to mulch a bed around them.

Pruning, three step system

Pruning is an art form that most people know every little about. Today I will talk about proper pruning techniques and how to tell if your Arborist is pruning your tree correctly. Tree pruning can be done for a few different reasons, one for form or shape, dead wood removal, lowering risk and aesthetic appeal. This can be done by the home owner or an Arborist.

Cuts should be done outside of the branch bark ridge and collar of the tree. Cutting into the wood can inhibit the tree from properly healing. This can leave an open wound for decay or insects to enter the tree. Cuts should be made so that there is also no stub or extra stem left behind. This can be harmful or poke someone’s eyes out! Ouch!

Cuts should be performed with a sharp pruning saw or a pair of secateurs. These are the best tools for pruning, if there is larger limbs to be cut off a chainsaw should be considered. If there is a large limb that is dead it would be best to call a professional. Dead wood can be unpredictable and may harm you. When using a chain saw it is a good idea to have the proper personal protective equipment on. This will include chainsaw chaps, steel toes, glasses and a hard hat with face shield.

Below is a link to a video on how to create a proper cut on a tree. This is a good way to understand and to learn how to prune trees correctly.   

Tree Selection

Tree selection is one of the most important step to building up our landscapes. Whether it be a new tree planting or replacing an older tree there are a certain set of questions you should ask yourself.

What hardiness zone do you live in? For example a palm tree from Hawaii will not survive out side in our could Alberta climate.

Why is the tree being planted? Do you want more fall color in your yard? To attract birds? Do you want shade or is it for privacy? 

What is the size of location that you want to plant this tree in? What is the soil like in that location? Is it mostly clay? Or sand? Is there good drainage? Remember a trees root zone can be 25% larger than the spread of the tree. Also ask yourself if there are over head or underground utility lines? Trees should never be planted under utility lines.

Some other things that should be considered are why was the previous tree removed? Was there a disease or pest issue? If so it is recommended that you do not plant the same species or family in that location. Another species would be best, it is also important to note the alternate species for the insect or pathogen. Another thing to consider is the tree species that your neighbors have on their properties. If you want to plant the same tree as one of the people in your neighborhood you are creating a greater chance for that insect or pathogen to take hold and spread.

Another thing to consider when choosing the future tree for your yard is the form of the tree. Will it block your drive way at maturity? Will the branches dangle down onto the roof of your house? 

 

The Smaller European Elm Bark Beetle

The Smaller European elm bark beetle Scolytus multistriatus, as talked about last week is causing problems in Elm trees. This insect is a wood boring insect; this means that it likes to lay its eggs under the trees bark. This insect also likes to eat at the green sap wood of the tree. This beetle is a brown to auburn in coloring. The adult beetles are approximately 1.9 – 3.1 mm in length. The larva are white in color, these are legless grubs. This bark beetle has one generation in the Canadian climate but is known in other places to have two generations in even warmer climates it can have upwards of three generations per year.

Larva will over winter in the Elm trees until the spring months. Adult exit the trees after the buds break, beetles fly in the summer months, they fly to dying Elm trees. The adults will pick up spores upon leaving the trees. These adults go to new healthy hosts and feed on the soft wood found in tree unions. The beetles that leave the trees between the months of April to the July are the most likely to vector Dutch Elm Disease. At this time of the year the trees xylem is openly flow for the bud break of the tree. The beetles will establish themselves under the bark and interfere with the xylem.

After feeding on the healthy Elms, the adults will tunnel into the dyeing, weakened, dead or in decline Elm trees. The beetles will then lay their eggs, these eggs will hatch and the larva will create feeding galleries. These run parallel with the grain of the wood, these have been said to look like caterpillars with long legs. These larva have a life cycle from 35 to 40 days. The larva become adults and emerges from the trees to feed. 

          

Dutch Elm Disease

Dutch Elm Disease (D.E.D) Ophiostoma novo-ulmi is a fungus that effects Elm’s Ulmus spp or Zelkova which is native to Europe. American Elm is the most susceptible. This fungus grows inside the xylem of the plant, this inhibits the trees ability to move water through the tree. This kills large parts of the tree, and causes wilting. This can spread quickly between Elm trees that have root grafts between there root systems.

In the spring infected trees will have few to no leaves on some branches. In early summer green leaves will wilt or droop on branches. Some leaves may even turn brown, but the leaves will not fall off they will cling to the tree. In late summer leaves will turn yellow and droop these leaves this is a common occurrence known as flagging. These leaves are also known to fall off of the tree prematurely. Branches on the truck will wilt and turn brown as well. 

What can you do to keep D.E.D out of Alberta? Make the effort to keep our trees healthy, this can be as simple as watering from April to mid-August. Watering your trees very well before the ground freezes for the winter can also help the trees to harden off. Dead and dying branches are the perfect place for the Bark Beetle to make its home. These should be taken care of and disposed of properly by either burning or burying the wood. 

These are some things you should not do. Do not store elm firewood, it is illegal and can be a breeding area or the beetle. Do not transport firewood into or even within Alberta. There is a pruning ban effective between April 1st and September 30th each year. Do not prune elm trees within this time frame.

Emerald Ash Borer

Emerald Ash Borer Agrilus planipennis is not common to Alberta, Canada or the United States. It is an invasive species from Asia that were first introduced in the United States in the mid 1900’s, has now been found in southern Ontario. This beautiful beetle is <10.0–13.0 mm in length. With a coppery abdomen, the elytra can be a duller green, purple, blue or even copper in color.

The larva eat the soft wood underneath of the bark, hindering the tree from moving water or sugars throughout the tree. This can kill a tree in one to three years.

This insect prefers Green Ash fraxinus pennsylvanica over Black Ash Fraxinus nigra, but it has been found on both these species in the USA and Ontario. Green Ash make up a large part of the street tree canopy of Calgary. The Emerald Ash Borer knows no boundaries and is headed our way. It is no longer a question of if, but of when.

So what can you do to prevent too spread of Emerald Ash Borer? Don’t bring fire wood across our Alberta border, prune the dead branches out of your trees, water and fertilize applications. Removing the low value trees from our landscape can help us to center our preventative measures on higher value trees.

There is a biological insecticide being used in Ontario called TreeAzin. This is a systemic pesticide that is injected into the tree, this should be applied every two years. This can be used on already infected trees. This has been tested throughout the USA and Canada for control of Emerald Ash Borer and has proved to be successful.