Retrofitting mulch basins around existing trees

Hi Art, have you done this or seen it done? I live in a dry climate so like new trees to be in the bottom of a basin with lots of mulch. This is irrespective of grey water or not, but I got the idea from your book. Most trees locally are planted conventionally and I'm curious if it's possible to retro fit mulch basins and whether that's possible for small, medium and large trees.

I've just trialled it on a young peach tree I thought was dead but has resprouted from bottom but don't want to do other healthier trees if this is messing with the root system.

Anyone?

I have constructed mulch basins around many trees of varying sizes. The approach I have taken is to start digging at the drip line of the tree to my desired depth. I then determine which direction (away from or towards the tree) I can expand the basin depending on what size of roots I encounter during the excavation. I prefer not to disturb any significant sized root during the work. On some systems I have reconstructed/expanded the mulch basin further away from the tree as it grows larger.

I retrofitted my conventional looking orchard with trees on flat ground, after reading Art's book when installing a laundry-landscape system. I dug in paths (1.5 feet deep) around my trees and used the dirt to create a berm around the tree. This effectively raised the tree for better draining, and provide a basin to collect water. The trees were young (2 years old). I also did it on a ten year old tree orange. I also just worked at the edge of the drip line. Trees have done really well. We've been in a historic drought in California, and I've kept my small orchard about 8-9 mulched basins doing pretty good with mostly just laundry water and what little rainwater I could capture. Mulch saves a ton of water. I attached a diagram of my idealized urban orchard retrofit, based on Art's graywater info and Pauls paddock and hugel culture stuff. My little berms are 30" wide and I cultivate the tops with annuals within the orchard, mostly greens that can thrive in the shade and feed the chickens.

Walter's system makes sense to me, since it avoids the potential pitfalls, i.e.
- smothering existing roots
- raising the soil level around the trunk
- cutting the shallow feeder roots

I wonder if this constrains the growth potential of the tree, since feeder roots often grow well beyond the drip line. But in a backyard situation that might actually be desirable to limit the size of the tree.

Hi, Rose...

I swear I answered this previously...perhaps it didn't go through.

I think all the previous answers are on the right track.

Also--

• I have successfully created basins a bit at a time over the course of years, to avoid massive root disturbance
• Trees chronically end up too deep. We have an awesome new mulch basin drawing (one of several in the new edition) that shows a variety of measures to combat this...comments welcome.


Yours,

Art

Thanks for all the replies everyone! That's a great selection of ideas and experience and gives me heaps to go on with.

Walter that's a great diagram!!

Art Ludwig wrote:
• I have successfully created basins a bit at a time over the course of years, to avoid massive root disturbance
• Trees chronically end up too deep. We have an awesome new mulch basin drawing (one of several in the new edition) that shows a variety of measures to combat this...comments welcome.

Is the main reason for raising the tree in the middle to stop rot? I live in a pretty dry climate, so have thought putting the tree at the bottom of the basin best, but I don't have a lot of experience. Presumably this is less of an issue with existing trees, although the peach we just did has mulch higher than the base of the tree (am keeping an air gap around the trunk).