[advice requested] how much sun do various tropical fruits actually need?

Let’s try a different way of approaching this kind of question so that we have a common language that can be applied to all situations.

In a mature forest there are trees that come out on top forming the canopy, others that grow just below them, others that grow on the bottom layer etc. Their places are defined by the needs of each plant for sub and shade. Of course, each plant will have their own maximum height. So a plant that grows up to three meters and needs lots of sun won’t have any chance of surviving in a mature tropical forest.

Let’s translate the needs of each individual plant in light requirements. Let’s call the position that each plant needs to be in on order to receive adequate light, it’s stratum. We can call them low (usually low and shade tolerant plants such as cardamom), medium/low (low light needs such as coffee or cacao),  medium (such as feijoa or pitanga), Medium/high (such as macadamia or loquat), high (such as lychee, mango or apple), high/emergent (such as tamarind or pear) and emergent that have very high light requirements (such as artocarpus or grape vines).

Understanding this will allow you to combine plants in a very small space and design your field in four dimensions (in length and width, in height but also in time, as you can have plants that occupy a stratum temporarily as the other plants around them are growing and ending up cutting it once its stratum has been occupied by other higher plants. For example, lavender is an emergent stratum plant. You can start a field planting lavenders, pears and mango but once the fruit trees are grown you will have to cut your lavenders down and replace them with cardamom.

In the case of your specific plants psidium is high, pineapple guava is medium, loquat is medium/high and cherimoya is also medium/high.

Of course the layout of your plantation will vary depending on the topography, latitude and other plants already established in your garden. Of your have other questions don’t hesitate to ask.

Hey all, another maybe-newbie question about how to interpret sunlight requirements. When I google most of the trees I want to grow (psidiums, pineapple guava, loquat, cherimoya) it says they need full sun and to space the trees like 10-15′ apart. But when I watch YouTube videos of folks with amazing tropical fruit forests, often including these fruits, they seem much more densely packed, often with just like 4-5′ between trees (it looks like), in dappled sunlight to shade (because the trees are packed so densely), and they look (to my untrained eye) healthy and productive. Plus, many of these trees are tropical and presumably evolved to live in somewhat forested conditions? 

I don’t have a ton of space, but I’d rather have a few really healthy trees than lots that don’t produce well or are sickly, and I don’t want to doom my plants by planting them too close (they’re in containers now). I’m wondering what folks with more experience can advise me about spacing and shade requirements to have healthy trees with lots of fruit.

I’m in the Bay Area (East Bay), zone 10a, pretty cool summers (rarely above 90F) if that helps.

Thank you!