In the last 10 years, there are lot of problems with birches (Betula pendula), what's happening?
Who/what?
It may be the fault of the fungal pathogen Neonectria sp. or oomycete Phytophthora sp. - rather in combination.
May be easily confused with Taphrina betulina, but the symptoms are much more widespread and the consequences are more serious.
Symptoms?
Hollows, bumps, cracks and other anomalies, thinned crown, smaller leaves than normal, dried tree branches, "bellies", lot of dead shoots, fractures of larger branches, "bumps" in the root collar area (up to 1,5 meters), leakings and often "life belts" in the same area, plus the round (not eccentric) shape of the wind roots - besides, I have also seen the presence of hydrotropy on sick trees.
Why/how?
Hypothesis - In 2005, Pärnu (a small town in Estonia) was hit by a strong January storm, resulting flooding a part of town with a seawater.
Saltwatered dense soil could be the reason why the pathogens started to act.
Most of Phytophthora species are attacking a root systems and the root collar area - so it is logical that the primary symptoms appeared in the crowns of trees about 5-6 years after the flood, ie in 2010/11.
Is it wise to cut the bad branches out of the crown?
I have noticed that cutting off the still living branches deepens/accelerates the degeneration, so it would be advisable to cut off only dead branches.
The biggest problem is raising the crown - this should not be done if possible - because of H/D factor, inhibition of diameter growth, water and nutrient transport.
What to do?
Trees try to deal with their own problems itself - by reducing their crown in the case of extensive root damage, and also by drying out branches.
The development of the pathogens is individual for each tree, which is why they need to be reviewed regularly and act accordingly.
In the urban environment, there is a serious risk of breaking/rupturing larger branches.
In case of Betula pendula - the biggest risk of breaking branches is in the late autumn after the plant has drained the crown of juice - it is that we lose the elasticity - which is replaced by brittleness.
So, unfortunately, it is so that in the next 15 years, many-many birches will have to be cut and replaced with more appropriate species in area.
Source: Urbandendro
http://ravelreiljan.blogspot.com/
 | ||
| Thin canopy of Betula pendula. Photo: Ravel Reiljan |
Who/what?
It may be the fault of the fungal pathogen Neonectria sp. or oomycete Phytophthora sp. - rather in combination.
May be easily confused with Taphrina betulina, but the symptoms are much more widespread and the consequences are more serious.
 |
| Deformations in the trunk. Photo: Ravel Reiljan |
Symptoms?
Hollows, bumps, cracks and other anomalies, thinned crown, smaller leaves than normal, dried tree branches, "bellies", lot of dead shoots, fractures of larger branches, "bumps" in the root collar area (up to 1,5 meters), leakings and often "life belts" in the same area, plus the round (not eccentric) shape of the wind roots - besides, I have also seen the presence of hydrotropy on sick trees.
 |
| Deformed Betula pendula. Photo: Ravel Reiljan |
Why/how?
Hypothesis - In 2005, Pärnu (a small town in Estonia) was hit by a strong January storm, resulting flooding a part of town with a seawater.
Saltwatered dense soil could be the reason why the pathogens started to act.
Most of Phytophthora species are attacking a root systems and the root collar area - so it is logical that the primary symptoms appeared in the crowns of trees about 5-6 years after the flood, ie in 2010/11.
 |
| Bleeding area above the root collar. Photo: Ravel Reiljan |
Is it wise to cut the bad branches out of the crown?
I have noticed that cutting off the still living branches deepens/accelerates the degeneration, so it would be advisable to cut off only dead branches.
The biggest problem is raising the crown - this should not be done if possible - because of H/D factor, inhibition of diameter growth, water and nutrient transport.
 |
| Broken Betula branch. Photo: Ravel Reiljan |
Trees try to deal with their own problems itself - by reducing their crown in the case of extensive root damage, and also by drying out branches.
The development of the pathogens is individual for each tree, which is why they need to be reviewed regularly and act accordingly.
In the urban environment, there is a serious risk of breaking/rupturing larger branches.
In case of Betula pendula - the biggest risk of breaking branches is in the late autumn after the plant has drained the crown of juice - it is that we lose the elasticity - which is replaced by brittleness.
So, unfortunately, it is so that in the next 15 years, many-many birches will have to be cut and replaced with more appropriate species in area.
Source: Urbandendro
http://ravelreiljan.blogspot.com/
No comments:
Post a Comment