pruning arbutus tree on waterfront cliff

hello. We have a mature arbutus tree perched on high bank waterfront. If it fell down it could take a substantial part of the property with it. The root ball is exposed but the tree except for a couple of dead limbs appears healthy. We would like to prune back the crown and possible remove a limb or two, but we do not want to do anything that might endanger the tree. Are Arbutus trees tolerant of heavy pruning? Any information would be greatly appreciated.

 

Whacking the top will add insult to injury. Have a qualified arborist or two look at the situation, make some recommendations.

 

Thank you. Whacking the top off is not what we intend to do - we were just wondering how much we can prune an arbutus without hurting it.
Unfortunately, living on a gulf island, it's not always that easy to get an arborist to come. Thank you though for your input

 

Tree is having a problem at the root, substantial crown reduction would add another problem. Same as with topping trees for other reasons, it does not really solve the problem - healthy trees grow back - and only gives the tree a harder time.

 

Are roots exposed from erosion?

Are there root ends sticking out, or just tops of some roots partially exposed?

 

Thank you for your quick response. We don't want to top the tree, just lighten it's load. We were wondering really if arbutus take well to pruning. The entire root ball is free of any soil, it is hanging off a cliff. Some of its roots go into the cliff and that is what is keeping the tree upright and alive.

 

My field observations are that coastal Arbutus are incredibly resilient structurally, even when dead for a short time. The foliage will respond to changes in its root network very rapidly, and if there is a sudden change in the root zone preventing water and nutrient uptake you will very likely see signs of wilting and dieback shortly. A risk assessing arborist will evaluate potential structural issues with root zone erosion, overall plant vigor and existence/extent of disease.

As for pruning as an option to manage a weakened structural root zone, a typical Arbutus crown density and structure doesn't leave a great deal of room for thinning or end weight reductions and the plant may desperately need that energy production to maintain defense and response to the changing soil situation. Arbutus resistance to disease is a major issue -- particularly with Arbutus canker, a disease caused by the fungus Nattrassia mangiferae. It's common throughout the range, and aggravated by other factors (eg. cold weather, snow loading/wind failures and poor/over pruning practices).

It's a complex set of issues, meaning I would also advise you to have an arborist by to assess your tree and make a recommendation specific to your site and the tree's current condition.

 

Actually, arbutus respondes extremely well to crown reduction. The best way to keep madrone foliage green and healthy is to reduce them.

And, in this case, with a (typically) leaning tree in a location where windthrow would be disastrous for the slope, considerable weight reduction is the only method that will be effective.

You might google Julian Dunster. He's one of the very best consulting arborists anywhere, and he resides on Bowen Island, I think it is......He may know a local climbing arborist.

Roger

 

I'm embarressed to say what we've done to one of our arbutus's on Mayne. First a windstorm took off a large branch, followed by some poor intentional limbing (to let light in). It's as strong and healthy as ever. However, no matter how light you make the tree, it sounds like soil erosion may eventually bring it down. Good luck!

 

How kind! I am now based in Victoria, having moved from Bowen after 17 years there. My experience with Arbutus is that it will tolerate pruning. If it has the canker pruning that part out may help, though probably not much. If the original poster wants to send a photo that may help. Cheers. Julian Dunster 778 433 8465

 

That is perhaps the most dangerously vague nugget of insight I think I've seen to date on UBC.

Crown reduction is not a blanket strategy, nor is coppicing. They are both tools in the box for certain scenarios, sure.

 

A picture would definitely be a help, we could have a look at the limb structure and make suggestions.