Lesions on Seiryu branches

Discussion in 'Maples' started by Margot, May 23, 2019.

  1. Margot

    Margot Well-Known Member

    Messages:
    555
    Likes Received:
    132
    Location:
    Nanoose Bay, BC Canada
    I just noticed these lesions on a branch of my 'Seiryu' maple and wonder if they are normal or a symptom of disease. If the latter, what can I do about it? It is otherwise a very healthy tree - about 15 years old now.
     

    Attached Files:

  2. JT1

    JT1 Contributor

    Messages:
    1,356
    Likes Received:
    344
    Location:
    Euclid, OH USA
    It's an old bacterial infection. The old infected bark dies and as wound wood forms to "heal over" it expands and the dead infected bark flakes away. They should be fine, except the last one. Rain water needs to be able to flow out of the bottom without getting into the scar. You can see the last photo water maybe getting under the bark and causing rot down the trunk.

    Instructions to follow when I have some more time today.
     
  3. Margot

    Margot Well-Known Member

    Messages:
    555
    Likes Received:
    132
    Location:
    Nanoose Bay, BC Canada
    Hello all, JT1 in particular. I'd be very grateful for further instructions on how to deal with the lesions on branches of my beloved Seiryu.

    Did I happen to mention one time that I bought it for $13 about 10 years ago at the local grocery store? It was about 3 feet tall and could barely stand on its own. Now it has grown to be a gorgeous tree, I want to ensure it stays healthy.
     

    Attached Files:

  4. emery

    emery Contributor Maple Society 10 Years

    Messages:
    2,015
    Likes Received:
    309
    Location:
    Normandie, France
    Hi Margot, nice tree. The lesions have healed and you really don't _need_ to do anything more. If you _want_ to do something, that's another story. Like putting almond butter on a scar in human skin, it might help the aesthetics. Personally, when a tree -- such as yours -- has successfully fought off an infection and healed up, I prefer to leave nature to take its course. -E
     
  5. JT1

    JT1 Contributor

    Messages:
    1,356
    Likes Received:
    344
    Location:
    Euclid, OH USA
    When we look at wounds we need to think about water and it's ability to run out. In addition, we need to consider freeze thaw.

    When water gets under bark it can cause rot from the inside out. When water gets under bark and it freezes, it can lift the bark away from the heart wood, allowing more water to work downward or sometimes even around the trunk.

    Gravity forces water downward. When a wound has a clear and defined V water can escape out the bottom point of the V. You can also see this V shape form after branches are removed and they begin to "heal" or form wound wood. This V shape lends itself to protecting the surrounding bark as the wound closes. It creates a natural drip edge, forcing water out at the bottom so it can run down the trunk on the outside. We never want water on the inside getting beneath healthy bark, again due to rot and the expansion of water as it freezes.

    When we look closely at these photos it tells a story of the past and the trees attempt at healing. In a perfect situation we have green bark that formed the wound wood and it's closed up, water tight, and perfect.


    Some wounds unfortunately don't have it so easy. Japanese maples are slow healers in general, but some cultivars are quicker than others. Time of year plays a role. For example a branch removed in late May will close by September provided the tree is healthy, the size of the branch being removed (smaller is better), the age of the tree (JM in it's teenage years heals much faster than a very young tree or a tree that is very old). A branch removed going into extreme drought or Winter will close much slower, which may lead to several failing attempts at healing.

    Bacterial infections can complicate things because we have dead tissue right next to alive tissue. The alive tissue maybe slightly weakened. When the infection goes dormant, the wound wood begins to form underneath the dead tissue. In some cases when the tree regains it's health the wound wood can actually form quickly because it's actually being protected by the dead bark (not exposed to drying winds, somewhat sheltered from the extremes of Summer). As the tree grows, wound wood expands, and the dead bark tissue above gets weathered cracks form letting in water. Water can gather in pockets and in most cases settle into the bottom of the wound underneath the dead bark. This is where rot and freeze thaw can start to damage the live bark surrounding the area in question.

    In the case of the last photo we see how the small wound killed the bark down into the larger wound below. Now below the larger wound, we can see how gravity is drawing water and rot down the trunk. It will either stop when it hits the ground or we get a crack at the bottom which may let the water to escape and run down outside of the healthy bark. I have seen it go both ways. But if it goes all the way down the trunk it typically results in death from heartwood rot, bug infestation, further bark separation from freeze, and even carpenter ant infestation.

    We covered the what and why. In the next post I will cover how to correct the problem.
     
    Last edited: May 30, 2019
  6. Margot

    Margot Well-Known Member

    Messages:
    555
    Likes Received:
    132
    Location:
    Nanoose Bay, BC Canada
    JT - Thank you so much for taking the time to explain the factors that have created this situation and I look forward to hearing your suggestions on how to correct it. I don't suppose there is much I can do to prevent this sort of thing happening again . . . I can say for certain the current problem was not caused by the removal of even small branches so I wonder how water found its way under the bark.
     
  7. JT1

    JT1 Contributor

    Messages:
    1,356
    Likes Received:
    344
    Location:
    Euclid, OH USA
    The water got under the live bark when cracks formed in the dead bark killed by the bacterial infection.

    Photo 1 shows example of dead bark caused by a bacterial infection. Notice the cracks in the dead bark for water to enter. Notice at the bottom the dead bark cracked and some flaked away allowing an exit point for any rain water that may enter the wound from any cracks above. (If we didn't have an exit point, water gathers and gets under live bark below, rotting it from underneath the live bark causing it to die further down the trunk)

    Photo 2 shows a infection after dead bark has flaked away and wound wood has formed to close the wound. It's about 95% closed.

    Photo 3 shows an infection that the wound wood has completely closed and is about 3 years closed and healed. (Starts to blend in with the surrounding bark as it ages)

    I hope this offers some clarity. That way we can talk about fixing it if your comfortable.
     

    Attached Files:

    Last edited: May 30, 2019
  8. JT1

    JT1 Contributor

    Messages:
    1,356
    Likes Received:
    344
    Location:
    Euclid, OH USA
    A few options exist. You need 91% rubbing alcohol. A very sharp knife like an exacto knife. We must have a knife that cuts the bark without tearing or smashing the existing green live bark.

    Options based on skill and comfort level:
    Area being discussed-
    https://forums.botanicalgarden.ubc.ca/attachments/seiryu-3-jpg.166166/

    The least invasive approach, low comfort. (See photo 1 below)
    Take cotton with alcohol and carefully sanitize the blade. Use the cotton ball to also sanitize the bark. Make a small V cut in the brown bark at the very bottom. We are not cutting the green bark. The cut is made at the edge of brown and green bark, but we are only cutting the brown dead bark. Cut across the top of the V. Use the edge of the blade to lift up the brown triangle piece. You now have created a place for rain water to escape which will stop the rot from spreading further down the trunk.

    Option two. (See photo 2 below). Clean blade with fresh alcohol. Use alcohol to sanitize the green bark along the edge of brown and green bark. Cut a straight line from the Start here point down to the stop point. The cut should be along green/ Brown line. But still on the brown side, not cutting any green bark. Follow the second cut down the right side (start stop point). Using the knife blade lift up the brown bark, careful not to damage or lift any green bark.

    Once cut away area is cleared away. You want to sanitize your knife. Sanitize the green bark. These next cuts matter. We must make a clean cut on the green bark just outside of our first two cuts. The green bark must be a clean cut, no tears, no jagged edges, and they must be straight down stopping at the bottom of the V. In order to heal these cuts must be done correctly, so don't rush. Then the remaining bark on the inside of the V remaining can be removed.

    Why 2 cuts? Well I have found when you do one V cut, then remove the dead tan brown bark it contaminates the green tissue edge where the wound wood forms. This can delay healing. When we make our first V cuts on the dead side of bark, we have an opportunity to clear away the dead bark while the green edge is still unexposed. Once the dead tissue is cleared away, it gives us an opportunity to make a clean final cut in the green live bark. This prevents contamination and allows for quicker healing.

    The other options are a bit more involved. I will post as time permits.
     

    Attached Files:

    AlainK likes this.
  9. Margot

    Margot Well-Known Member

    Messages:
    555
    Likes Received:
    132
    Location:
    Nanoose Bay, BC Canada
    Thanks once again, JT. I will be sidelined for a couple of days but attending to my maple will be a priority once I'm up and about. I'll be sure to report back how it goes.
     

Share This Page