Published
A buffer is arithmetic, not landscaping taste.
A buffer has a width, and the width is calculated rather than chosen
When a county condition says a development must provide buffering, the instinct is to plant a row of trees along the boundary and consider it done. Fremont County's Appendix K sets out an actual method — a basic width, an adjustment for building height, and a set of reductions you can earn. It is arithmetic, not landscaping taste.
One thing to say plainly first: this is buffering between land uses. It is a separation standard for mitigating conflict between neighbouring uses, and it is a different provision from the vegetation buffers that protect streams and lakeshores.
“The width of required buffers shall vary with the nature of the uses being separated, the height of the buildings being separated, and the construction of the buffer, as shown in Table K.1.”
— Fremont County Development Code, 2011 Edition (Ordinance 2011-04), Appendix K, section 1.02, Minimum Buffer Requirements. Consolidated through Ordinance 2026-03. Retrieved 1 September 2026
Three variables, then. What is being separated, how tall it is, and what the buffer is made of. The table supplies the starting number for a given pair of uses; the rest of the appendix tells you how that number moves.
What the basic width assumes you are building
The basic width in the table is not the width of empty ground. It is the width required where the buffer consists of a specified minimum, and knowing that minimum tells you what a compliant buffer actually looks like.
| Element | What Appendix K requires |
|---|---|
| Ground surface | A level or gently sloping area, 3:1 slope or flatter, of sod or ground cover |
| Planting | At least four major trees per hundred lineal feet of buffer |
| Absolute floor | No required buffer may be less than half the basic width, or less than 10 feet, whatever reductions are earned |
| Fencing | A security fence along the property line is required for all buffers shown on Table K.1 |
| Fence extent | It must extend 300 feet beyond the terminus of the required buffering, unless it meets another fence or reaches the property boundary |
The fence provision is the one most likely to be missed at budget stage. It is required, it runs along the property line, and it carries on 300 feet past where the buffer itself stops. That last requirement exists so a buffer cannot simply be walked around at its end, and it can add a meaningful length of fence to a job.
The floor is worth noting too. Reductions are available, but nothing takes a buffer below half the basic width or below ten feet. Ten feet is the hard bottom regardless of how much is planted.
Before any of that arithmetic, there are five things worth establishing about the boundary in question, because each one changes the answer:
- Which two uses are actually being separated, since the basic width is read per pair rather than per property.
- The height of the principal structure being buffered, measured against the 25-foot allowance.
- What is already growing along the line, and whether any of it qualifies as a major or understory tree.
- Whether the ground will take a berm at 3:1 or flatter without a retaining wall.
- Where the buffer terminates, since the security fence runs 300 feet past that point unless it meets another fence or the property boundary first.
- Whether a variance will be needed, which the appendix expressly contemplates where site conditions and dimensions do not accommodate the calculated width.
Taller buildings need wider buffers
The height adjustment is straightforward once stated. The basic buffer width is increased by a height adjustment factor where Table K.1 establishes one. That factor is a ratio expressing the number of feet added to the basic width for each foot of height over 25 feet of the principal structure being buffered.
So 25 feet is the free allowance, and everything above it is charged for at the ratio the table gives for that pair of uses. A structure at 25 feet adds nothing; a structure well above it can add a good deal, and the addition is a function of the building rather than of the site.
The practical consequence is that building height and land take are linked on any project carrying a buffer condition. A taller building consumes ground twice — once beneath itself, and again in the buffer it widens.
How to earn the width back
The appendix is generous about reductions, provided they are built rather than promised. Two mechanisms, and they stack.
A berm. The width reduction is twice the height of the berm, capped at a maximum reduction of 10 feet. No berm may be steeper than 3:1, except where a retaining wall is incorporated on the side opposite the use being buffered, and the interior toe of the berm slope must be no more than 25 feet from the interior edge of the buffer.
Additional plantings. Where greater density and diversity of planting is included, reductions are available and are cumulative, up to a total reduction of 30%. The berm reduction is cumulative with these.
- Major trees — any deciduous tree reaching more than 30 feet at maturity, or any conifer. A 10% reduction where two or more per hundred lineal feet are planted or retained in addition to the required four.
- Understory trees — any deciduous tree reaching less than 30 feet at maturity. A further 10% reduction where two or more per hundred lineal feet are planted or retained in addition to the required trees.
The phrase planted or retained is the valuable one. Existing trees count. On wooded corridor ground that is a real advantage, and it argues for surveying what is already growing on a boundary before clearing it — because a mature conifer standing in the right place is worth a percentage off the buffer, and a stump is not.
Working the numbers in the right order
- Read Table K.1 for the specific pair of uses being separated. The basic width and any height adjustment factor are pair-dependent, so there is no general answer.
- Apply the height adjustment for anything over 25 feet, using the ratio the table gives.
- Survey the existing trees along the boundary before doing anything else, since retained trees earn the same reductions as planted ones.
- Work out whether a berm is feasible, remembering the 3:1 slope limit, the 10-foot cap on its reduction, and the 25-foot limit on where its interior toe may sit.
- Add the planting reductions, up to the 30% cumulative ceiling, and add the berm reduction on top of that.
- Check the result against the floor: never less than half the basic width, never less than 10 feet.
- Price the security fence along the property line, including the 300 feet beyond the buffer's terminus, which is easy to leave out of an estimate.
The appendix ends its purpose section with a sentence worth carrying into any of this: site conditions and dimensions may require a variance to achieve substantial compliance. The code anticipates that a real site will not always accommodate the calculated result, which is a more workable posture than it first appears — and it is the same reason the corridor rewards checking each lot on its own terms rather than assuming a standard applies uniformly. A buffer condition is also a required improvement under the county's phasing rules, so it falls inside the guarantee a phased subdivision has to post.
Common questions
How wide does a required buffer have to be?
It varies with the uses being separated, the height of the buildings, and how the buffer is constructed, as set out in Appendix K's Table K.1. There is no single figure — the basic width is read from the table for the specific pair of uses.
What does the basic buffer width assume?
A level or gently sloping area of 3:1 slope or flatter, of sod or ground cover, with at least four major trees per hundred lineal feet of buffer. That minimum construction is what the basic width is priced against.
Is there a minimum buffer width?
Yes. No required buffer may be less than half the basic buffer width or less than 10 feet in width, regardless of any reductions earned through berms or additional planting.
Does a buffer require a fence?
A security fence is required along the property line for all required buffers shown on Table K.1, and it must extend 300 feet beyond the terminus of the required buffering unless it intersects another fence or reaches the property boundary.
How does building height affect the buffer?
The basic width is increased by a height adjustment factor where the table establishes one. That factor is the number of feet added to the basic width for each foot of height over 25 feet of the principal structure being buffered.
Can a berm reduce the required width?
Yes. The reduction is twice the height of the berm, capped at 10 feet. No berm may be steeper than 3:1 except where a retaining wall is incorporated on the opposite side, and the interior toe must be no more than 25 feet from the buffer's interior edge.
How much can extra planting reduce the buffer?
Planting reductions are cumulative up to a total of 30%. Two or more major trees per hundred lineal feet beyond the required trees earns 10%, and two or more understory trees per hundred lineal feet earns a further 10%.
What counts as a major tree?
Any deciduous tree that reaches a height of more than 30 feet at maturity, or any conifer. An understory tree is any deciduous tree reaching less than 30 feet at maturity.
Do existing trees count toward the reductions?
Yes. The appendix says trees planted or retained, so mature trees already on the boundary earn the same reductions as new planting. That is a strong reason to survey a boundary before clearing it.