With a few free days I am trying to determine tree locations for a new build in Colorado at just about 40 degrees N. I understand the sun is 30 degrees south of East/West line at winter solstice. The house will be oriented almost due solar south, I will rotate the house 10 degrees to the east to eliminate possible ice damming concerns in a garage/house roof valley on the north side. I'm having a hard time determining the distance from the house as well as where to plant the trees for summer screening/shade. It looks like if I draw an "X" through my house from corner to corner that would be N.E. to S.W. and N.W. to S.E.(the house is a rectangle, 28'x 50') I get a pretty fair approximation of sun points for the AM and PM sun locations for the winter solstice at sunrise and sunset. So far so good, but how far out should I plant relative fast growing deciduous trees, ash, maple, linden, and such? I'll plant about 15' trees with at least a 2" caliper trunk diameter. Can the community give me some guidelines, Please. Dan

I would plant deciduous trees fairly close to the house and trim all the lower branches such that there is little or no shading of the windows in winter.

Have you ever seen "SketchUp"? Some of the free 3-D rendering software available online does a pretty good job of shadowing and ray tracing using sun positions.

I second ICF Hybrid's recommendation. The free version of Sketchup plus some of its free add-ons will allow you to do some really good planning. For example, you can download a Google Earth picture of your land into Sketchup, introduce contours of the land, place your house properly on the land, show shadows as a function of time of day and time of year. You can download some crude deciduous and evergreen trees and place them where you want, and see their effect upon shading. It is a neat and powerful program. I live in Evergreen, CO and used the program to help me decide what trees, if any I should cut down for better winter sunlight. I live on the north side of a steep hill (in the east, they might call it a mountain) which is fairly heavily forested. It turns out, there is not much point in cutting down many of the spruce and fir trees on my property for sunlight purposes, because the sun drops behind the hill at about 1:30 in the afternoon at this time of year. For fire mitigation, I will cut down lots of them.

I am using sketchup, but the tree growth (heights) are iffy. I guess I will have to do some interim sun mitigation until trees gain some height and bulk.
Thanks for the hints.

you can move the trees up off the ground to make them taller.

I think you mentioned it earlier by saying you are planting 15' trees. Be just in case.

If you plan on future solar PV or Thermal, make sure the trees you plant will not eventually shade the south roof of your home. You can buy Dwarf, and semi-dwarf variety's of many common species, that have relatively predictable maximum growth heights. Pair that knowledge of maximum tree height with sketchup, and you're set.you can use the scale tool to make the trees wider/ taller.

Assuming you will have appropriate overhangs on your windows to the south, you should mostly need shading on the east and west of the house (favoring west). So your X method is pretty good. I like to plan for the future, so i would keep most trees of any real girth/ height at least as far from the house as they will grow in height in case they ever go over in a storm. Smaller trees could go closer, i would not worry about a shrubbery tearing down my walls

I don't know exactly where you are or your site conditions, but also consider more trees between the house and the prevailing winter winds, to help act as a wind screen. I imagine they would contribute in a SMALL way to summer cooling as well just by cooling the air before it gets to the house (evaporation in the relatively dry Colorado air), but unless you plant a substantial stand of trees, I wouldn't count on the cooling effect as significant.