Low Voltage Uplighting of Trees

Uplighting of trees adds drama and vertical emphasis in a garden lighting scheme. Smaller trees can be effectively lit with low voltage outdoor spotlights and recessed lights. The principal beam angles of low voltage halogen reflector lamps are 12, 24, 36 and 60 degrees. If you are uplighting a slender tree the coverage of a 60° beam will be wasted in the night sky; a narrower beam will “fit” the shape of the tree more closely. The diameter of the beam can be matched to the tree’s shape as indicated in the graphic and table below. If a 60° (wide flood beam) lamp in a garden uplight will not provide both height and breadth of coverage, try using two lights with overlapping narrower 38° degree beams to give the required coverage. In walkover areas use cooler led or lower power Powersaver lamps to protect against contact with a hot lens or consider a 35w metal halide uplight. As 240 volt GU10 halogen lamps are less efficient than 12 volt halogen reflector lamps, they generally lack the power to light trees.

Powersaver 12 volt MR16 halogen lamps now provide increased efficiency compared to standard MR16 halogen reflector lamps. A 50w Powersaver now does the same job as a 75w standard MR16 halogen lamp and a 35w Powersaver now does the same job as a 50w standard MR16 halogen lamp: this means 50w spotlights can now be used instead of 75w MR16 spotlights for tree uplighting applications. The table below shows approximate vertical coverage for trees with open structure and canopy

Uplighting tree examples

Recommended Lamp Selection
Tree Shape: A: Columnar B: Slender C: Medium D: Spreading
Lamp beam angle: 12 degree 24 degree 36 degree 60 degree
Powersaver 35w MR16 - - 6m 4m
Standard 50w MR16 10m 8m 6m 4m
Powersaver 50w MR16 - - 7m 5m
Halogen lamp type Elipta 12 Volt spotlight/uplight selection
35-50w MR16 Powersaver COMPACT spike spotlights and twin spike spotlights; POLE SPOT DUO; POLE SPOT SOLOMODULA recessed uplights

Suggestions are for guidance only; lighting effect will be affected by colour/darkness/density of foliage

See also:
Choosing halogen lamps for 12v garden lights

Metal halide uplighting for larger trees

Copyright 2014; Information based on products supplied by Lighting for Gardens Limited and is advisory only. The company accepts no responsibility for incorrect use or application of information given. Light fittings can become hot in use; exercise appropriate precautions. Exterior electrical installations should be undertaken by a qualified electrician.Graphic reproduced with permission from ”Garden lighting” by John Raine, published by Hamlyn 2001