Tree inventory helps arborists plan for Spokane’s future

It’s almost like money growing on trees.

A new city report has counted, measured and placed a monetary value on nearly every tree on city property.

And, at least according to the report, there are a lot of trees in town worth more than the cars parked next to them.

The inventory, presented to the Spokane Park Board this month, lists 86,554 trees that have a total value of $382,444,340. More than 13,000 of them are valued at more than $10,000 apiece. The most expensive is listed at $60,700. 

The purpose wasn’t about cashing in on the city’s urban forest, at least not in a traditional sense.

Angel Spell, Spokane’s urban forester, said the goal is to use the report to determine the needs of city trees. Among the questions it will help answer, she said: Where should more trees be planted? What species should be added? Where could more trees be planted to prevent untreated stormwater from flowing into the Spokane River? 

“The most important information I’m hoping to get from that inventory is ‘Where do we go from here?’ ” she said.

But the values are important, she said. After the 1996 ice storm, a major winter freezing rain event that damaged thousands of trees across the city, Spokane was able to make a claim with the Federal Emergency Management Administration based on the value of lost trees because it had just completed the previous inventory, Spell said.

The report employs a standard formula, also used by courts, to determine the value of trees, she said. Factors include a tree’s size, location and species; the replacement value also takes into consideration that a 100-year-old shade tree can’t simply be replaced by planting a sapling.

The inventory, which counted nearly 375 different species on city property, includes all trees on street rights-of-way and most parks, though about 25 mostly smaller parks are still to be completed. The inventory also excludes city conservation lands that are maintained as natural areas, such as Palisades Park.

Nearly all the inventory of trees along streets was completed by Davey Resource Group, based in Ohio, in an up-to-$250,000 contract that was paid for through stormwater fees. Park trees were reviewed by city urban forestry staff members.

City utility officials have taken an increased interest in trees as they prepare to slow the flow of untreated stormwater into the Spokane River. Rain that falls into streets picks up contaminants along the way to the river. But a substantial amount of rain that lands on trees just evaporates.

Park Director Leroy Eadie said the information will help the city apply for grants that could pay to plant more trees.

The new report lists each tree’s species, trunk diameter, height, condition and value. If the tree is between a street and sidewalk, it lists the width of the planting strip. That information is important when determining what species should be planted without threatening the sidewalk and hasn’t been recorded in other places at City Hall, Spell said.

Some findings weren’t surprising to park officials. Norway maples remain, by far, the most common tree on city property; they account for more than 17 percent of the city’s trees. The city already discourages planting more of the trees to guard against losing a large portion of the city’s tree canopy if a species-specific disease takes hold here.

The second most common is the ponderosa pine. City officials don’t discourage planting the big “bull” pines because as a native tree they are perfectly suited to the climate.

After working on Spokane trees for 16 years, city arborist Jeff Perry said he’s not surprised by much in the report. There are more oaks, yellowwoods and Japanese pagoda trees than he would have predicted. Also more blue atlas cedars, which he said seem to do fine here even though Spokane’s climate is supposedly too cold.

He added that there are a lot more trees on the city’s right of way than he previously understood.

The last extensive inventory of the city’s street trees was completed in the mid-1990s. But that report mostly counted trees between streets and sidewalks, Perry said. The new report determined the city’s actual right-of-way along streets and counted trees that many property owners may not realize are on city land.

He said the city’s urban forest has probably improved a bit in recent years; the city began enforcing pruning rules on street trees to prevent them from being topped. The forest’s biggest obstacle is a lack of diversity in the age of trees. 

“There’s a lot of older trees, not many middle-aged trees and a lot of younger trees,” Perry said. “There’s a gap that could be a problem down the road.”

Dr. Edward Lester, a retired orthopedic surgeon who has researched numerous trees in Eastern Washington, said Spokane is the home of many trees that are the largest of their species in Washington. They are detailed in his new book “Champion & Historic Trees of the Inland Northwest.” 

Lester said many of the older trees likely were paid for by the voter-approved park tax in 1910 that bought, among other things, 80,000 trees.