What Now? Tar Spots On Maple Trees, These Are Fun-guys Only

Anna Lozyk Romeo — Tue, 15 Nov 2011 21:03:57 +0000

I have seen those dark spots in the summer on the Red Maple, and they are nearly invisible on the dark leaves – only if you look closer. However, in the fall they are too visible so I couldn’t resists to find out what it was. A contrast of black spot on yellow leaves does not make a pretty maple tree.

Tar Spots, Red Maple Tree

I am sure that by now everyone heard about the Asian Long-Horned Beetle, the Emerald Ash Borer and Yellow Headed Spruce Sawfly infestations. The latest and greatest is the borer and the sawfly. Borer is an invasive insect that kills all different species of healthy ash trees. The sawfly feeds only on the spruce trees. I guess we are missing a natural predator for those insects.

The classic scenario I experienced on my backyard was the infestation of ladybugs. This was few years ago and once in the while I still find one or two of those nasty ladybugs in my house. Since the ladybug population decreased over few years I do find more aphids in my garden. Releasing ladybugs, a predator to aphids, is one of few natural methods to control garden aphid infestations.

Then this one I will never know. About three or four years ago we were driving on Hwy 404 to work. It was just before Hwy 7, for about five minutes of driving we saw dark funnel clouds on top of many trees, no not tornadoes. It wasn’t like only one or two trees, it was hundreds of trees. What kind of bug it was I have no idea.

May be someone will after reading this post.

Tar Spots, Red Maple Tree

So what is going on with Red Maple trees on my street?

I was able to narrow down my search to the tar spots. Black spot, also called tar spot, on maple leaves are caused by fungi in the genus Rhytisma (whatever it is? my Latin isn’t that good anyway). Leaves usually become infected in the late spring or late summer and may fall off prematurely. These tar spot are not usually detrimental to the maple trees.

In our case here, it is already November and the leaves are falling due to natural fall cycle. Some are still hanging to the tree even with these spots.

Tar Spots, Red Maple Tree

And the treatment is? The fungus winters-over on leaves that have dropped to the ground. The leaves need to be raked up in the fall otherwise the spores will reappear in the spring on the old leaves and spread to any nearby tree. Well, we definitely have the spread on all trees, but everyone been raking them and composting. Hopefully it will go away.

Treating your maple tree is usually not effective. You cannot just treat one tree, you have to treat them all in the neighborhood, and for now raking is the solution.

Bleeding Red Maple Trees, The Cry After Winter

Anna Lozyk Romeo — Fri, 29 Apr 2011 20:29:44 +0000

The annual tree pruning of roadside trees in our subdivision started mid January of this year. It was kind of unusual to see that it was done in the winter, but I am no expert to know how it will affect the trees in the future. Apparently the Parks Division in Town of Aurora has two fully trained and experienced municipal arborists on staff, responsible for 90% of our forestry operations, and I guess they will know the procedures.

Tree Trimming, Town of Aurora, January 2011

However, I did little research as always. No, I couldn’t really find anything unusual about trimming trees in the winter and especially trimming of the Red Maples – until I noticed this couple of months later.

Sap Bleeding Red Maple Tree, Town of Aurora, April 2011

Around mid March of this year I noticed water dripping from the trees. First I thought that it was water from the melting snow that accumulated between the tree trunks, just like melting glaciers on the mountains. No, it was the oozing maple sap. This bleeding process of the maples was carried over to almost mid April. It almost felt like being a part of the Maple Syrup festival, this is how much bleeding there was going on from all the cuts to the Red Maples.

Just Simple Explanation: What Happens In The Maple Tree?

‘Understanding how maple sap is formed requires some knowledge about tree physiology. In the later summer and fall, maple trees virtually stop growing and begin storing excess startches throughtout the sapwood, especially in cells called ray cells. This excess starch remains in storage as long as the wood remains colder than about 40 degrees F. Whenever wood temperatures reach around 40 degrees F, enzymes in the ray cells change to starches to sugars, largely sucrose. This sugar then passes into the tree sap. As the temperatures increase to about 45 degrees F, the enzymes top functioning and sugar is no longer produced. In March and April, the sugar changes back to starch – except during periods of flow. Rising tempeartures creates pressure inside trees, causing sap to flow. When a hole is bored into a tree, wood fibers that are water- (sap-) carrying vessels are severed, so sap drips out of the tree.’

Source: The University of Maine Cooperative Extension

According to more of my Internet research elm, maple, walnut and birch will bleed sap when pruned in the later winter to early spring. We don’t have to worry too much as we don’t park cars directly under the trees, but the sap can drip on cars and sidewalks. I also tried to find if the oozing sap is harmful to the trees, and some think that the bleeding sap can interfere with the closure of pruning cuts. What is the alternative then? Trim trees in the fall, but then fall is least desirable because cuts close more slowly than in any other seasons. Another source says to trim plants with a high sap flow in the late spring or early summer.

Sap Bleeding Red Maple Tree, Town of Aurora, March 2011

To conclude, no worries – tree trimming should be fine in the winter as I couldn’t find any warnings. Well, if it is not, I will let you know, as I will be watching my maple tree. I hope nothing happes, because it is now a very good size tree to provide shade for the grass and walkers.

Living in Aurora, Town of Aurora, Ontario » Red Maple

What Now? Tar Spots On Maple Trees, These Are Fun-guys Only

Bleeding Red Maple Trees, The Cry After Winter