Trees aren’t the first things you think of when you think about New Mexico, but Albuquerque’s urban forest is a important environmental tool.

Nick Kuhn, city forester, was one of the speakers at the New Mexico Xeriscape and Water Conservation Conference in Albuquerque last month. I guess it never occurred to me that cities in the southwest would need foresters, but by the time Nick finished his talk, I was a believer.

Nick explained that even the southwest needs an urban forest and street trees are valuable “solar-powered environmental tools.” Each tree is a natural resource for economic, social and environmental benefits.

However, in the city of Albuquerque many residents have stopped thinking of trees as an important part of the ecosystem equation. With water at a premium, and a big push to conserve it, many think that a treeless yard saves water. But nothing could be farther from the truth.

Fall fell with a “thud” this weekend after two nights of subfreezing temperatures.

The green ash tree in my front yard went from fully leafed to fully bare branches seemingly overnight due to two days of unseasonably cold temperatures.

On Friday morning, after the first night of subfreezing temperatures, I went outside and leaves were falling like rain from many of the uppermost branches and the lawn was covered with a thick layer of green leaves.

On Saturday morning, after the second night of subfreezing temps, the tree had but a few leaves on its lower branches. All of the other leaves had landed beneath the tree in a perfect circle just outside the outer edge of its canopy.

Of course I was immediately concerned with the health of this 25-year-old tree, especially after reading recent reports of a looming ash tree crisis.

Black walnut trees are in decline along Colorado’s Front Range and the results could be devastating.

The news is bad for Front Range homeowners with black walnut trees in their yards.

Boulder officials are telling residents that their trees will have to be cut down. This may comes as a surprise for some, but as early as 2004, CSU researchers had identified a decline in black walnut tree populations that was spreading in several western states and had appeared along the Front Range.

In October 2007, CSU plant pathologists were warning of the walnut twig beetle (Pityophthorus juglandis) causing major decline of Juglans nigra in Boulder, Westminster and Arvada.

The report found that multiple trunk and branch cankers were caused by a fungus carried by the beetle, but it wasn’t clear whether the insect came first or the canker.