Ask an Arborist

Today is Arbor Day! Do you have questions about trees? Robb Sgroi, our Land Resources Specialist, is a Certified Arborist through the International Society of Arboriculture! Here are some burning tree questions I had for Robb (terrible pun, I know).

Do you have any tricks for remembering how to tell the difference between pines, firs, and spruces?

As a kid raised by a father who studied forestry, the majority of our conversations centered around trees and birds. My dad would tell us “friendly fir, spiky spruce” was a rule of thumb. Firs have softer needles that are “friendly” to the touch, whereas spruce have spiky needles that aren’t friendly to touch. Arborists also point to spruce as sharp, single, short, and square.

Robb (left) in 2003 up Phillips Canyon.

Robb (left) in 2003 up Phillips Canyon.

Is my house at risk of ignition from a forest fire? What can I do to protect my home from a fire while still promoting forest health and wildlife habitat?

Teton Conservation District (TCD) offers Wildfire Risk Overviews to landowners, at no cost. These Overviews identify the conditions of the structure itself and vegetation, and voluntary recommendations are made that could reduce the potential of the structure igniting from wildfire. TCD offers financial incentives for implementing these recommendations. Wildfires are a natural disturbance which have an important role on the landscape. Our goal should not be to eliminate wildfire, but rather, to reduce our structure ignition potential. A great deal of preventative work can take place by landowners, to reduce risk to firefighters, landowners, and damage to structures.

My tree limbs and close to my roof and walls. Is this a fire risk?

Robb dropping some tree knowledge last fall.

Robb dropping some tree knowledge last fall.

TCD recommends pruning tree limbs at least 10 feet away from roof and wall surfaces, to reduce the potential for flames to directly contact your structure. However, a consultation with TCD on wildfire risk can help look into details. For example, it is recommended that not more than 25% of limbs be pruned in a single year. Plants need limbs and leaves to photosynthesize, and produce sugars!

When I pick a Christmas tree in Bridger-Teton National Forest with my family every December, we try to pick unhealthy looking “Charlie Brown” trees that might not make it anyways. Do you have any tips for picking Christmas trees in a way that promotes forest health?

Christmas trees?? I am looking forward to summer!
Following the land management agency regulations is the most important step in selecting a site and a tree. However, selecting a subordinate tree that is within the drip line, or crown area, of a dominant, larger tree, may be a good choice, by removing the tree that has lesser chance for robust growth.

I’ve seen trees with brown tops. Is that bad? What can be done about it?

Trees with brown tops could indicate some degree of damage or disease in the tree. It is not uncommon to see the dead or dying tops of trees to be altogether removed, a practice that arborists generally do not recommend. Topping a tree can introduce a point of entry for decay

Is there any technique to pruning trees that I should be aware of?
Pruning is an activity that, when done property, can support plant health. When done improperly, it can create a pathway for disease and decay. Hire a professional forester or arborist to support your projects, or contact us for simple advice on how to promote plant health care using good technique and tools.

Please reach out to Robb with any questions that relate to both arboriculture and wildfire risk reduction! His email address is or you can call us at 733-2110.