Japanese (and other Asian) maples are by nature understory trees and are accustomed to a part shade location. "Ideally", a situation that provided morning sun and afternoon shade is a preferred location, avoiding the more intense and hotter late afternoon sun. However, most red leafed maples can tolerate a great deal of sun without issues, provided all other growing requirements are met. Given the two locations outlined above and the size of the tree now, I'd not be too inclined to move it - it will be far less stressful and better for long term growth to leave in place. A JM with a 2-2.5" diameter trunk is a good sized tree and will not transplant easily. And you certainly do not want to comtemplate doing so now - if you must move, wait until dormancy.

Fred, The theory is based on Daily Light Integral - the total amount of light that a plant gets in a day. Sort of like using a rain gauge to determine not how hard it is raining but how rain we get from a shower. But in this case, it is the amount of PAR light, light in the 400-700 nm range. This link provides the amount of light needed for various greenhouse plants. This is to grow to maturity, not seedlings. On Page 4 of this page the formula for calculating moles (or mols) per day is provided. I've measured bright sunlight in summer with my meter and I get about 110,000 - 120,000 lux. Going with 100,000 lux, that's about 9300 foot candles. Multiply that by .000718 gives you 6.67 mols per hour. This is the scientific aspect but the anecdotal part is that I had tomato plants growing in my GH this winter that did nothing except get very leggy until I started getting about five hours of direct light a day. Even then, it was filtered a bit by plastic. But I had hundreds of blooms and now have bunches and bunches of toms. Eaten some, some are almost ready to eat and others will not be ripe for a month or more! Mike

I don't agree with blanket statements that more sun is always better. While this might be true in places with high humidity and lower elevations, here in the hot arid SW at 5000 feet, there is such a thing as too much sun, and plants which receive a few hours of shade/partial shade always produce better and are less stressed. Plants here that receive 12 hours of direct sunlight will develop a blasted look in the summer where the color is more grayish-green than lush green. The lower leaves get leathery faster than shaded plants, and the leaves rarely provide a flattened surface to the sun, no matter how carefully you maintain moisture levels. At a certain point here, sun ceases to be a critical component and becomes a stress factor. Plants grown in buckets in these conditions do even worse. They dry out very quickly, and the buckets can get extremely hot when placed on surfaces like concrete, brick, or stone. To help, you can put a layer of mulch in the bucket to help retain moisture, and if your ground temperatures are high, you can place the bucket higher up on some type of stand. Regarding your plants, yellow pear does have thinner, more sharply jagged leaves. It's typical of that variety. Under the right conditions, they can become obscenely large. Since you only have one plant to compare, it might not actually be the conditions that are unfavorable, but it could be the individual plant itself. When you transplanted the yellow pear, was it still in any type of peat container?

I've grown tomatoes in 6h of sun and they've done really well until fungus hit them, which I've wondered if the sunlight largely being afternoon sun has contributed to that. No morning sun=morning dew not drying all morning. Other than that, the plants have always been fairly healthy though. I would do as suggested above. You may be surprised at the production you get out of the 6h bed. It would be an interesting experiment. I'm not sure how warm it gets in the San Francisco area, but if it tends to get too hot where you live the 6h could be beneficial.