pawpaw trees: what is their natural form?

In Fukuoka's book natural farming he has a chart showing the natural form of several different types of trees. Now that I have pawpaws growing I'm wondering what their natural form is. I'd like to steer them towards this so I only have minimal or no pruning to do. I've noticed whenever I plant whips from the nurseries they start out fine but quickly get all tangled up.

Chris Holcombe wrote:In Fukuoka's book natural farming he has a chart showing the natural form of several different types of trees. Now that I have pawpaws growing I'm wondering what their natural form is. I'd like to steer them towards this so I only have minimal or no pruning to do. I've noticed whenever I plant whips from the nurseries they start out fine but quickly get all tangled up.

You may have to START with a heavy hand to convince something to grow the way you want, then after a season or two, you can sit back and just do a bit of maintenance. I have a quince, it can be convinced to 'tree' but it'd rather 'sucker bush'.  So maybe you need to apply a heavy hand with the first few years of your Pawpaw's life?

Here in Indiana, the native paw paws are often found in patches with a generally upright form.

a lone tree in the open is usually steeply pyramidal/cone-shaped. in the shade, tall and scragglier.

To be clear, I'm assuming you mean Asimina triloba.  If so ...

In Missouri and Nebraska (my experience) pawpaws are under-story trees growing in riparian zones. This may be what some consider the more "natural" form. In these conditions, the pawpaw trees that I've observed are tall and straight with sparse limbs limiting its energy to catching dappled sunlight that makes its way through the over canopy of giant cottonwoods and other river and creek trees. Here's a link to a photo: http://www.veggiegardeningtips.com/wp-content/uploads/2013/09/Gathering-Pawpaws.jpg

Plant them in the open and they will be shorter and more full and a somewhat conical in shape. They can be trained. Here's a link to a photo: http://darkroom-cdn.s3.amazonaws.com/2016/09/a9ebfc00fbdf8fd2bb836130d42f855e.jpg

I'd say their form is based on their conditions. I believe there are few pawpaw trees growing naturally in the open in the Midwest of the USA as seedlings don't tolerate direct sun very well and usually burn off the first or second year in direct sunlight. If shaded for the first three or so years, they can survive direct sunlight and will grow more like an orchard tree.

See extensive research by Kentucky State University http://www.pawpaw.kysu.edu/

People in some communities around the world refer to the papaya as pawpaw, so that's why I generally give the scientific name to remove all confusion.