| Name | Average | Stdev |
| alder | 1.56 | 0.73 |
| ash | 1.67 | 0.71 |
| aspen | 2.22 | 0.67 |
| balsa | 2.00 | 0.87 |
| banyan | 1.67 | 0.50 |
| baobab | 1.78 | 0.44 |
| beech | 2.22 | 0.44 |
| birch | 2.00 | 0.50 |
| bonsai | 1.78 | 0.44 |
| cedar | 2.11 | 0.60 |
| cypress | 2.00 | 0.50 |
| dogwood | 1.56 | 0.53 |
| elm | 1.67 | 0.50 |
| ginkgo | 2.22 | 0.44 |
| hemlock | 1.78 | 0.44 |
| hickory | 1.67 | 0.50 |
| laurel | 2.89 | 0.33 |
| locust | 1.89 | 0.33 |
| maple | 2.11 | 0.60 |
| mimosa | 2.44 | 0.53 |
| oak | 1.56 | 0.53 |
| palm | 2.33 | 0.50 |
| pine | 1.78 | 0.44 |
| poplar | 2.00 | 0.50 |
| redbud | 2.56 | 0.53 |
| redwood | 1.89 | 0.60 |
| rubber | 1.89 | 0.33 |
| sapodilla | 2.44 | 0.73 |
| sassafras | 2.56 | 0.53 |
| shagbark | 1.67 | 0.50 |
| spruce | 1.78 | 0.44 |
| sumac | 1.89 | 0.33 |
| sycamore | 1.78 | 0.44 |
| teak | 2.33 | 0.50 |
| tupelo | 2.22 | 0.44 |
| willow | 2.89 | 0.33 |
Number of responses: 9.