Question 1: Is the extra difficulty of installing lights in trees and on buildings to shine down upon a landscape worth the effort?
Pergantis. Ask anyone with a pulse and they will have an opinion on what effect is better, uplighting or downlighting. Let's compare uplighting and downlighting and you be the judge.
The first major benefit of downlighting, that is locating the fixture above the landscape in a tree, eave or on a pole, is the light beam illuminates a larger area. Light shines through the branches and leaves of plants casting interesting shadows onto the ground. This technique is commonly called moonlighting.
Because the fixtures are out of reach, vandalism is greatly reduced. Once the lights are set, little repair or adjustment is needed.
On the down side, more cable is needed. As a result, the amount of voltage reaching the lamp is slightly less. To compensate for lower voltage, increase the size of the wire.
Keep in mind that trees are constantly growing. Leave some slack in the cable and use an adjustable lag bolt to secure the mounting hardware. Also, do not hammer tacks all the way into the tree to secure the cable. The tree will grow over the cable and tacks with time.
Since downlighting can be used for spotlighting or cross lighting, plant growth can impact both the angle of the beam and any foliage blocking it. Downlighting resembles natural light due to its origin.
Uplighting is easier to accomplish, however it is rarely seen in nature. It gives a slightly mysterious appearance which demands attention. Uplighting illuminates the bark, innerworkings of the branch structure, and the under-sides of the leaves.
Maintenance of ground fixtures is easier, however debris can fall on top of the lamp and vandalism is more likely. You will need less cable during installation and will have the benefit of more voltage and brightness.
Fixtures are generally well-type or accent floods. Since these fixtures are within reach of any curious bystander, the threat of shock is important. Low-voltage lamps for uplighting eliminate this threat.
As you can see, there is no clear winner between uplighting and downlighting. They both have their own special place in an effective lighting design. Professional lighting contractors should be skilled at installing and maintaining both types of lighting.