What are the greenery requirements for a perfect town rating?

Solution 1:

The things that contribute to nature requirements for a perfect town (as far as I know) are:

1. Between 110 and 200 trees
2. More than 75 flowers

Additionally, some public works projects affect the amount of greenery in your town (see below).

Via this FAQ by Liquefy on GameFAQs under "Citizen Satisfaction". Relevant parts copied/pasted below for convenience:

"Abundant nature" means:
1) appropriate number of trees (not counting shrubs (newly planted saplings and 
bamboo don't count); "dead" trees (perfect fruit trees that have lost their 
leaves) DO count) (-1 point for each less than 110) (-1 point for each above 
200)
2) many flowers (not counting wilting) (+1 point for 51 to 75) (+25 points if 
more than 75)
3) high Nature Points from built Public Works

Here are the Public Works that affect Nature Points:

   Greatly increase:
...Flower Clock - 87,000 Bells (triggered by "perfect" status)

   Largely increase:
...Flower Bed - 26,400 Bells (suggested by Normal female villager)
...Flower Arch - 87,000 Bells (suggested by Normal female villager)
...Wisteria Trellis - 124,000 Bells (suggested by aneki female villager)
...Rack of Rice - 17,400 Bells (suggested by Cranky male villager)
...Circle Topiary - 93,000 Bells (Weeding Day)
...Square Topiary - 93,000 Bells (Weeding Day)
...Tulip Topiary - 93,000 Bells (Weeding Day)

   Slightly increase:
...Solar Panel - 126,000 Bells (suggested by Jock male villager)
...Wind Turbine - 156,000 Bells (suggested by any villager)
...Windmill - 372,000 Bells (suggested by aneki female villager)

   Slightly decrease:
...Picnic Blanket - 39,800 Bells (suggested by aneki female villager)
...Traffic Signal - 82,000 Bells (suggested by Jock male villager)
...Illuminated Heart - 136,000 Bells (suggested by Peppy female villager)
...Illuminated Arch - 148,000 Bells (suggested by Snooty female villager)
...Illuminated Clock - 146,000 Bells (suggested by Peppy female villager)
...Illuminated Tree - 128,000 Bells (suggested by Peppy female villager)
...Tower - 726,000 Bells (suggested by Snooty female villager)

   Largely decrease:
...Tire Toy - 49,800 Bells (suggested by Lazy male villager)

   Greatly decrease:
...Garbage Can - 53,000 Bells (suggested by Normal female village)
...Video Screen - 284,000 Bells (suggested by Jock male villager)
...Drilling Rig - 298,000 Bells (suggested by Cranky male villager)