Enter diameter at breast height (DBH) of the tree, optionally including up to 2 decimal places. DBH is measured 4.5 feet from the ground. For accuracy, use a tape measure to find the circumference of the tree at 4.5 feet, then divide by pi (3.14). For multi-stemmed trees separating below breast height, combine the diameter of each stem. For several trees, you may aggregate DBH up to 10,000 inches, but since the calculator cannot determine the number of trees, it cannot "grow" each tree and treatment cost will return somewhat low. Similarly when DBH is aggregated the calculator cannot reasonably estimate removal cost (it assumes one large tree), therefore estimates are not available for DBH over 48 inches.

The default duration of tree ownership is 15 years, reflecting a 50% cushion on the actual 10-year median duration of home ownership in the Nashville, TN area as of 2018 (source nar.realtor). The national median duration of home ownership as of 2018 was 13 years.

As a tree grows in diameter treatment cost will increase. A growth rate factor is the number of years required for a species to increase in diameter by one inch. The lower the factor the faster the growth. Factor tables were developed for forest trees growing in competition and may understate the growth potential of open-grown residential trees. The default factor of 4 is an estimate for open-grown ash, but the actual factor may be as low as 3 or as high as 5.

Enter the removal cost of the tree (or of the tree and the stump, leaving stump removal cost blank). For an estimate, enter diameter at breast height (DBH) of a single tree (maximum 48 inches) and click "Estimate". The estimate may be extremely inaccurate because cost and discount drivers other than DBH are not considered, including region, height, spread, rigging needs and accessibility.

Enter diameter at breast height (DBH) from 1 to 48 inches, optionally including up to 2 decimal places, and click "Estimate" again.

Enter the removal cost of the stump. The cost of stump grinding in the Nashville, TN area is about $3 per inch of stump diameter, measured not at breast height but at ground level at the widest point, giving effect to all visible root flares. Using this method stump diameter is significantly greater than DBH. A rough estimate of (1.75 x DBH) x $3 may be reasonable. Additional charges may apply to grind visible roots extending from the stump. For an independent stump grinder, a minimum trip charge of $150-200 should be expected. For an estimate on the terms above (excluding minimum charges), make sure you have entered the diameter at breast height (DBH) of a single tree (maximum 48 inches) and click "Estimate".

Enter diameter at breast height (DBH) from 1 to 48 inches, optionally including up to 2 decimal places, and click "Estimate" again.

The default tree removal year is the beginning of year 1, which is immediately. If the tree is healthy enough to consider a delay in removal, an extension of the removal year (e.g. to the beginning of year 2 or 3) will reduce the present value of the removal cost.

The standard cost to treat per inch is multiplied by DBH to arrive at a total cost of treatment. The default cost of $10 per inch of DBH reflects a typical charge for trunk injection of emamectin benzoate at a moderate labeled rate in the Nashville, TN area, while moderate-high or high application rates will likely cost more. If your provider recommends a higher application rate for a limited time (due to signficant dieback or high bug pressure), the provider's long-term maintenance cost per inch should be entered here and the short-term additional cost per inch should be entered in the additional cost field below.

The default treatment frequency of 2 years is the labeled EAB control period for trunk injections of emamectin benzoate.

This is a flexible field to account for additional treatment costs you may incur that are not already included in the standard cost to treat per inch. Enter the amount and select from two dropdown boxes, one with options for the duration of the extra cost (1x for the first treatment only, 2x for the first two treatments, or all) and the other with options for whether the cost is expressed per inch of DBH (/in) or as a sum total for the tree (sum). For instance, if your service provider recommends a higher application rate for the first treatment only and the extra cost is $4.00 per inch of DBH, enter 4 as the amount, select a duration of 1x, and select /in. Or if your provider has a $50 trip charge in addition to treatment cost, enter 50 as the amount, select all the cost applies to all treatments, and select sum to reflect that the amount is a sum total and not a cost per inch.

The default investment return rate of 8.38% is the compound annual growth rate (CAGR) of the S&P 500 for 20 years ended 12/31/21 with dividends included (source moneychimp.com); the CAGR of the S&P 500 for 30 years ended 12/31/21 was higher at 11.27%; the CAGR of the S&P 500 from its modern-era inception in 1957 through 12/31/21 was 10.67%. Note that the rate entered here should be the full nominal rate (inclusive of inflation) typically reported for market growth and not a so-called real rate of return (which is not directly observable and must be calculated by removing the effects of past inflation). The calculator will inflate all of your future costs by the inflation rate provided in the field below, so that for purposes of the NPV analysis nominal costs will be discounted correctly at a nominal rate.

The default inflation rate of 2.06% is based on average annual CPI data for 20 years ended 12/31/21 (source calculator.net); the CPI inflation rate for 30 years ended 12/31/21 was 2.31%. All of your future costs will be inflated by the inflation rate, compounding annually, to account for price increases over time. Using a long-term CPI rate is a conservative approach to the NPV analysis, considering that we are only concerned with inflation as it relates to the treatment of trees, where the cost of chemicals typically decreases slowly over time and more efficient injection equipment becomes available to offset increasing labor expense. In the Nashville, TN market for instance, the prevailing standard cost of treatment per inch of DBH has not increased in over 5 years.

Special High Inflation Note: The inflation rate has a powerful effect on NPV outcome. If your goal is to make the best financial decision, please resist the urge to apply the currently high economy-wide inflation rate to a long-term industry-specific analysis.

The default tax rate of 15% is the 2021 long-term capital gains tax rate for single persons with taxable income greater than $40,400 but less than $445,851 and married persons filing jointly with taxable income greater than $80,801 but less than $501,601 (source kiplinger.com). The tax rate will reduce your effective returns on investment.