The replacement value of a tree is calculated by 2 factors.
In many cases a tree of comparable size cannot be found so a smaller tree must be purchased or used as guide to determine the cost for a larger tree. Putting a value to a replacement tree larger than what is available is determined by:
1. The actual cost of the largest tree of that variety or species available.
2. Determining the growing cost per year to grow a tree to the age of the tree being replaced.
Example: If a 5-year-old tree could be purchased for $250.00, then dividing $250.00 by 5 years = $50.00 per year to grow the tree.
Let's say you have a tree that was 18 years old and it was hit by a vehicle. You would multiple $50.00 (the cost per year to grow the tree) by 18 (the age of the damaged tree) = $900.00 replacement tree cost.
Next figure the landscape value to the cost. Landscape value is very subjective. Japanese Maples and other specimen trees can be a major focal point and or play an important role in a landscape. If the landscape suffers because of the loss of the tree some monetary value can and should be associated. Actual monetary landscape value is completely subjective based on the landscape importance to the property and if there is a personal attachment to that plant or tree. For instance, I grew up with a Japanese Maple tree that was used as a backdrop to many of our family photos. I give that tree some attachment value, but you would need to provide proof showing the importance.
You may want to contact several different retail sources for an average tree cost in your area. Just ask for the price of the largest tree available of that variety and the age of the tree.
Also be sure to include the planting cost and cost to remove the existing tree if necessary.