SOURCE: Tell me about the work you do in the CSU Spur research grove. What are you trying to learn, what problems are you trying to solve, and what makes your research important for the average person? 

Martin: The work in the CSU Spur Research Grove is a collaboration between CSU research faculty, scientists and the Colorado State Forest Service. The Grove is a research platform with a primary commitment to quantifying landscaped tree species’ water use and drought stress tolerance.

Our research will help identify species that are more susceptible to drought and require more water, more frequently. These data will help the average person to select “water wise” species that are more appropriate for our climate. The data will also help to inform how water can be applied more efficiently for irrigating trees in our landscape.

How are the unusually warm winter and spring impacting the CSU Spur Research Grove? 

Our recent warm winter required more frequent irrigation. For example, we needed to water twice as much as we did during the same season in 2024-25. I irrigated every 1.5 to two weeks this past winter versus every three to four weeks the previous year. 

The watering frequency that I practiced for the 2025-26 winter would be more typical for fall or spring irrigation.

Flower and leaf buds appeared two to three weeks earlier than they did the previous spring. 

How is the drought impacting the urban forests along the Front Range? Anything particularly unique you’re noticing?

Drought stress renders trees more vulnerable to diseases and pests, which manifest harm on specific life cycle schedules. West Denver metro residents who own pine trees in proximity to mountain pine beetle, for example, could expect their trees to struggle more than usual with fending off that pest. 

Colleagues at the Colorado State Forest Service are reporting that Front Range mountain communities are experiencing this pressure.

What trees work best in Colorado’s climate?

Colorado’s climate is highly variable: Trees need to be cold, heat and drought tolerant. The Front Range Tree Recommendation List, updated in 2024, recommends many different trees including chinkapin oak and bigtooth maple.

 A beautiful New Mexican bigtooth maple is included in the water use studies at the Spur Research Grove.

What tips do you have for people as they take care of their trees this summer?

Particularly if trees are young, irrigate your trees directly below the outermost branch tips, where water absorptive roots tend to locate. Irrigate in accordance with regulations, which are supportive of trees. Water should be applied slowly, generously and directly onto the soil surface, but infrequently, allowing soil to dry out between waterings. 

Visiting and appreciating your trees regularly will make it easy to keep an eye on them to irrigate with optimum timing. It is more helpful to be observant of and irrigate according to soil moisture rather than adhering to a strict irrigation schedule; doing so more efficiently utilizes rain to complement and reduce the need for irrigation.

Mulch your trees to help them retain soil moisture, to keep roots cooler in hot summer months and to provide nutrients. Check with your city offices to see if they provide free mulch; many do.

Where can we learn more?

Much good information about tree and plant care can be found on Colorado State University Extension webpages. Visit those pages, and if you have questions, contact your local Extension office. Extension professionals are highly knowledgeable and enthusiastic. They take great pleasure in helping residents better care for their trees.