The Gresham tree count that could move an industrial layout

A tree inventory can look like a task for after the building, parking and utilities are arranged. On a Gresham industrial acquisition, that sequence could produce the wrong layout.

The City’s October 5 tree-code draft would add a site-tree ratio for industrial development, give extra planting credit for retaining larger qualifying trees, and sort removals into new permit categories. A mature tree could therefore help satisfy the proposed planting count while its protected root area pushes a wall, drive aisle or utility in another direction.

That is a design-stage decision, not merely a future permit detail. Before pricing clearing or freezing a concept plan, a buyer should know where the trees are, which might qualify for retention credit, which are proposed for removal, and whether the retained trees physically fit.

The draft is not current law. Gresham’s current code still controls, and the proposal may change through hearings. But the proposal is specific enough to test a layout now—without pretending to know the final rule, permit result or cost.

The decision: Keep the concept layout, redesign around selected trees, or pause until the tree facts are known.

Current rule: Gresham’s current industrial standard requires at least 15% of net site area to be landscaped. Current tree-removal and replacement rules remain in force.

October 5 proposal: The draft Section 9.1000 would add one site tree per 5,000 square feet of required industrial landscape area after deducting parking-lot landscaping. It would also let qualifying retained trees count as one, two or three required site trees.

The trap: Planting credit, permission to remove a tree, replacement duties and the physical protection zone are four different questions. A favorable answer to one does not settle the others.

Check first: a surveyed tree inventory, the required-landscape calculation, the removal count and categories, and the proposed building/utility overlap with root-protection areas.

What this changes now: Do not price clearing or approve the layout from a tree count alone. Run the trees through the plan before the plan becomes expensive to move.

The proposal would require a development tree-protection plan to inventory non-exempt trees on the site and certain nearby trees. The listed fields include species, trunk diameter, health and structural condition, and whether each tree will be removed or retained. Those are also the facts a design team needs to test the proposal intelligently.

A count without locations cannot reveal a collision with a building pad. Diameter without health and species cannot establish retention credit. A removal total without tree categories cannot establish the review lane. And “retain” written on a plan does not prove that grading, trenching or pavement can fit outside the protected root area.

The commercial question is simple: Does the current concept still work once the tree facts are placed on it?

Consider a hypothetical 200,000-square-foot net industrial site. This is not a real parcel or reported project.

Under the current 15% industrial landscaping floor, the example starts with 30,000 square feet of required landscaping. Assume 5,000 square feet is parking-lot landscaping. Using the October 5 proposal’s industrial method, that leaves 25,000 square feet for the site-tree ratio. At one site tree per 5,000 square feet, the preliminary proposed count is five site trees. The numbers divide evenly; the reviewed draft does not tell us how a fractional result would be rounded.

Now place three existing trees on the concept plan:

The draft would count a retained and protected tree from 8 to less than 12 inches as one required site tree, a tree from 12 to less than 36 inches as two, and a tree 36 inches or larger as three. On size alone, the three trees produce six possible credits against the five-tree planting count.

“Possible” matters. The draft retention standard also calls for a certified arborist to find each credited tree in fair-or-better health and structural condition, and the tree cannot be on Gresham’s invasive plant list. It must actually be retained and protected. The credit does not substitute for additional buffer-tree, parking-lot-tree, street-tree or special-overlay requirements.

So what do six credits buy the reader? Not approval. They identify an option worth investigating: Can these three trees satisfy the preliminary site-tree planting count while leaving a workable building, circulation and utility plan? If yes, retention may avoid planting additional site trees under this one proposed ratio. If no, the sixth credit is irrelevant to the layout.

The preliminary result is five proposed site trees and six conditional retention credits. This screen says the retained-tree strategy may cover the proposed industrial site-tree ratio. It does not authorize any removal, cancel replacement duties, or settle the rest of the landscape plan.

Assume the plan also calls for removing ten non-exempt Site Trees. The draft says “Removal of ten or fewer Site Trees” can fall within proposed Tree Removal B, a Type I review. Eleven moves the basic screen to Tree Removal C, a Type II review.

That 10-versus-11 comparison is useful, but it is not a permit result. The proposal calls for the highest applicable review and considers additional applications at the same site within 12 months together. Significant Trees, overlays, development context and the removal criteria can change the route.

Replacement is separate again. The draft says Tree Removal B and C can require replacement under the proposed planting standards; its “Other Site Trees” provision generally describes 1:1 replacement unless the applicable site-planting ratio is met without replacing the tree. Other tree types and locations carry different obligations. The draft also appears to contain an unresolved replacement cross-reference, so this example cannot safely convert six credits into “all replacement satisfied.” That is a City-confirmation question, not an assumption for the pro forma.

Now test the 20-inch tree. Under the proposal, its critical root zone starts with a 20-foot radius. A new encroachment would be allowed under the stated exception only when all existing and new encroachment covers less than 25% of the root-zone area and no new encroachment enters the inner half of the radius—10 feet in this example.

This is not permission to shrink the radius by 25%. It is an area limit plus a separate inner-distance limit. Put the building edge, paving, grading and utility trenches on the same plan as that zone. If the plan cannot meet both conditions, an alternative approach would need the proposal’s arborist-supported path or the layout may need to move.

That is why the tree with two planting credits can still be the tree that forces redesign.

Use this completed example as the first pass, then replace every assumption with project evidence:

Favorable: The survey and arborist confirm all three trees qualify; their protection zones fit; the preliminary five-tree ratio is covered; ten or fewer removals stay in the expected lane; and no overlay, Significant Tree or prior approval changes the analysis. Carry the concept forward, but describe it as tested against the October 5 proposal—not approved under future code.

Adverse: One tree is invasive or in poor condition, an inner protection area intersects a building or utility, the plan needs an eleventh removal, or another rule creates a higher review. Redesign before pricing clearing. Compare moving the building or utility with retaining a different combination of trees; do not solve the problem by deleting a credited tree from the inventory.

Unknown: The landscape base, parking deduction, tree survey, health, overlay status or prior approvals are missing. Pause the tree conclusion. The missing evidence is material to both layout and permitting, so “we will confirm later” is not a reliable design assumption.

City of Gresham

Certified arborist

Commission or update the tree survey before the civil and landscape plans harden. Put trunk locations, diameter, species, condition and proposed treatment into the base drawing. Then show root-protection geometry and count removals by category.

Use current code for today’s entitlement and permit work. Use the October 5 proposal as a scenario test: if its planting, retention or protection mechanics would change the plan, preserve that flexibility now rather than discovering the conflict after design coordination.

When discussing the site with a client or capital partner, say:

The October 5 draft’s industrial row points to §7.0310(A), while Gresham’s current industrial landscaping standard is §7.0320(A). A proposed replacement clause also appears to point to §9.0120 rather than the site-tree section. This issue leaves both references unresolved pending City confirmation. A September 21 staff memo used different retention-credit diameter bands; the later October 5 draft bands are used here. No adoption date, effective date, future fee amount or rounding rule was verified.

Gresham Development Code hub

A City staff memo schedules a Planning Commission hearing for November 9, 2026 and a City Council hearing for December 8, 2026. Those are scheduled proceedings, not outcomes.

The consequential check is the November 9 packet: Did the industrial ratio, retention bands, removal thresholds, replacement language, protection-zone rule or cross-references change from the October 5 draft? Any material change should update the site test before the concept is relied on. December 8 is the next scheduled decision point; it does not establish adoption or an effective date.

If this would help someone evaluating or designing a Gresham industrial site, forward it to them.

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