Review Korean forest land before committing to a purchase
A low land price or a visible access track does not establish that a Korean forest parcel can be converted for a house or warehouse.
Restrictions discovered after signing can put survey fees, design spending and the purchase decision at risk.
This calculator compares selected surveyed figures with Korean 2026 numerical criteria and identifies information to obtain before further spending.
The result covers the displayed numerical checks.
Article 18 of the Mountainous Districts Management Act also addresses restricted activities, disaster risk, forest ecology and project suitability.
Meeting four displayed limits does not establish full permit eligibility or replace the competent authority’s decision.
The decision and next action
Use the review to decide whether to commission surveys, investigate a different development location or obtain conditions before contracting.
Discuss permit-related contract conditions with the person handling the contract.
Use the separate conversion-charge and restoration-deposit calculators when preparing funding.
2026 national reference limits
The general conversion review follows Enforcement Decree Article 20(6), Annex 4, item 2(c).
An applicable ordinance or facility exception can change the review.
A value exactly equal to an inclusive upper limit is within that limit.
National slope, timber stock and older broadleaf forest criteria and their scope| Criterion | Upper limit | Applicability |
|---|
| Average slope | 25° / ski facility 35° | Generally also applies below 660 m² |
| Grid area at or above 25° | 40% | Ski facilities excluded |
| Site / municipal standing timber | 150% | 660 m² or more; check subdivision scope |
| Broadleaf forest aged 50+ years | 50% | 660 m² or more; check subdivision scope |
The 25-degree average-slope test and the share of grids at or above 25 degrees are separate tests.
A low average can coexist with an excessive steep-grid share.
Find the right survey values and units
Slope and area
Use the average slope from a qualified surveyor’s report.
For the grid ratio, use the confirmed denominator excluding land preserved in its original form within the project site.
Enter the surveyed area at or above 25 degrees separately.
Using the entire registered parcel as the denominator can understate the ratio.
Forest stock and statistics
Standing timber is entered in m³/ha.
Do not confuse total timber volume in m³ with volume per hectare.
The municipal comparison must be the applicable current-year city, county or district figure with relevant provincial growth adjustments.
A nationwide average is not a substitute.
Leave unknown numbers blank.
Blank values do not become zero or an exclusion; enter zero only for a confirmed absence.
Keep the review date, forest survey date and evidence reference with the figures so that later changes in the application date can be reviewed.
Average slope and the steep-grid calculation
Enforcement Rule Annex 1-3, note 2, describes digital terrain mapping, a 10 m × 10 m grid and area weighting of triangle slopes from a triangulated irregular network (TIN).
An angle estimated from a web map or a simplified contour-length arctan formula does not replace that survey method.
This tool compares a reported average; it does not perform terrain surveying.
Displayed margins
- Average-slope margin = applicable limit − surveyed average slope
- Steep-grid ratio = grid area at or above 25° ÷ denominator excluding preserved land × 100
- Maximum steep-grid area = denominator × applicable percentage limit ÷ 100
- A percentage margin is in percentage points (%p); a negative margin means the value exceeds the limit.
With a 1,000 m² denominator and 300 m² of steep grids, the ratio is 30%, leaving 10 percentage points below the national 40% limit.
Do not enlarge the denominator with preserved land or infer the grid distribution from the average slope.
Changing the development location requires a revised survey of both figures.
The 150% stock test and forest survey validity
Compare the same year and unit
Stock ratio = site m³/ha ÷ municipal m³/ha × 100.
Maximum stock = municipal stock × applicable percentage limit ÷ 100.
Stock margin is maximum stock minus site stock, in m³/ha.
A density limit alone cannot determine a maximum total area eligible for conversion.
From the year after publication of the forest statistics until new statistics are published, the prescribed provincial average growth rates adjust the municipal figure to the relevant year.
The calculator does not invent a national growth rate or automatically compound guessed figures.
Enter a checked adjusted value and confirm that the relevant growth and survey adjustments are reflected.
Recent logging or fire does not erase the prior stock
When fire, thinning or logging occurred less than five years ago, the survey must reflect pre-event stock converted through the survey date.
Entering current low volume or zero just because trees have been removed can misstate the review.
Exactly five years is distinct from less than five years; confirm the actual event date and conversion method with the surveyor.
Rule Article 10(2)(1)(f) requires the relevant forest survey to have been prepared within two years before application.
This tool checks the entered review date, includes the corresponding date two years earlier and keeps future survey dates pending.
Recheck at the actual application date if filing is delayed.
This is not a blanket two-year expiry rule for the separate average-slope report.
Below 660 m² and subdivided development
The area column of Annex 4 item 2(c) applies subitems 1 and 2 below 660 m², and subitems 1 through 4 at 660 m² or above.
Small projects therefore do not automatically escape average-slope and grid-ratio review.
For a confirmed ordinary small-area case, the stock and older-broadleaf numerical rows are excluded.
Check subdivision and document submission separately
Annex 4 note 3 allows all four subitems to apply when a plan is recognized as subdividing the forest for conversion below 660 m².
Unknown subdivision applicability leaves the stock and broadleaf rows pending.
Splitting applications is not an automatic way to remove the criteria.
Forest survey submission exceptions have separate conditions under Rule Article 10, including tree presence and aggregation of multiple applications with an identical project purpose.
A numerical exclusion, a document submission exception and restoration-deposit exemption are distinct.
Do not transfer an area threshold from one system into another.
Ordinances, ski facilities, solar and exceptions
National defaults and a confirmed ordinance
Decree Article 20(7) permits specified criteria to be tightened or relaxed by ordinance within the delegated scope.
The general 10% and population-decline-area 20% delegation does not let an applicant select an arbitrary relaxation.
Custom mode requires all three confirmed limits and an ordinance reference.
Unknown rules retain national defaults as a reference comparison.
Separately check development-permit slope conditions in urban planning ordinances.
Ski and solar procedures differ
Annex 4 sets a 35-degree national average-slope limit for ski facilities and excludes them from the 40% grid test.
Stock and broadleaf review are not universally excluded.
The solar 15-degree figure is in Annex 2 for land designation or determination consultation; it is not a universal replacement for the general 25-degree conversion criterion.
Selecting solar displays a 15-degree reference margin and keeps the overall decision pending while the applicable temporary-use or other procedure is confirmed.
Facility exceptions and project size
Annex 4 note 1 lists facilities including defense and disaster restoration exceptions.
Note 1-2 provides a stock exception for specified national advanced strategic industry research facilities installed as urban or county planning facility projects.
Prior consultation reviews, individual committee decisions and other special cases require confirmation.
Annex 4-2 also contains the general restriction on permit areas of 30,000 m² or more, with exceptions and aggregation rules.
Those conditions are not determined by these four numbers; select exception review when applicable.
Step-by-step use
- Enter the review date, purpose and applicable conversion area.
Use land-use records and authority consultation to identify the forest category, ordinance and exceptions.
- Copy the average slope, grid denominator and steep-grid area.
Confirm that the survey covers the proposed development location; this tool does not carry out GIS surveying.
- Enter same-year site and municipal stock, the older-broadleaf share and forest survey date.
Check recent disturbance and current-year adjustments.
- Select documented evidence only after surveys and applicable rules are actually checked.
Assumed figures support comparisons while the overall result stays pending.
- Read exceeded limits and pending reasons, then save the TXT review or print it.
The statement includes evidence references and unresolved information for the authority and surveyor.
Worked fictional 1,000 m² example
Assumed inputs
General conversion area: 1,000 m²; average slope: 24°; grid denominator: 1,000 m²; steep-grid area: 300 m².
Site stock is 210 m³/ha, municipal stock 160 m³/ha and older-broadleaf share 40%.
The forest survey date is 2026-10-01 and review date 2026-10-21.
No event less than five years ago and current-year adjustments are assumed.
Calculated comparisons
The average-slope margin is 1°, and the 30% grid ratio leaves 10 percentage points.
Maximum steep-grid area is 400 m².
Stock ratio is 131.25%, maximum stock is 240 m³/ha and stock margin is 30 m³/ha.
The broadleaf share leaves 10 percentage points.
The example stays in assumed mode, so its overall result is pending even though the four figures are within their limits.
Replace the assumptions with your documents and confirm the applicable rules before treating the selected numerical review as met.
Comparison uses unrounded values; a tiny excess is not erased by display rounding.
Use the review for purchase or inherited-land decisions
Before paying for design, separate existing evidence from missing survey work and request the appropriate quotes.
If the average slope is within its limit but steep-grid share exceeds it, ask the surveyor to investigate alternative development locations.
Removing selected land from an informal calculation does not establish that the revised plan would be permitted.
For inherited forest land, obtain prior logging history, conservation classification and legal road access information.
A visible forestry road or actual vehicle traffic does not automatically satisfy Annex 4 item 1(e)(10).
Project purpose, disaster risk, drainage, landscape, ownership or use rights and other approvals remain separate checks.
Connect the review with funding
Conversion charges and restoration deposits are separate funding obligations.
When a numerical limit is exceeded, first verify the rule and survey scope.
When figures are within limits, discuss outstanding road, ordinance and project-size conditions before preparing the related funding.
The ability to pay a charge does not establish permit approval.
Frequently asked questions
Does exactly 25 degrees exceed the limit?
The general national rule is inclusive at 25 degrees.
Ski facilities or a confirmed ordinance can have a different limit, and the steep-grid test remains separate.
Is slope ignored below 660 m²?
Average slope and steep-grid ratio generally still apply.
Confirm ordinary small-area scope and subdivision before excluding stock and broadleaf review.
Can I enter zero after logging?
An event less than five years ago can require conversion of pre-event stock.
Use the qualified survey result rather than the current appearance of the land.
Can a national average replace municipal stock?
The comparison is the relevant-year municipal figure.
Check the forest statistics and provincial growth adjustments; leave unknown data pending.
Does solar need only a slope below 15 degrees?
The verified 15-degree figure is an Annex 2 designation-consultation criterion.
Confirm temporary use or the actual procedure and other requirements; the overall review here remains pending.
Can I add a 10% relaxation myself?
The statutory delegation is distinct from the ordinance actually in force.
Enter confirmed limits and their legal reference, and keep individual-review cases outside the general decision.
What if the forest survey is older than two years?
Figures can remain as references, but stock and broadleaf decisions are pending when the required forest survey falls outside the review-date window.
Recheck documents at the actual application date.
Can I contract immediately when all four checks pass?
Restrictions, disaster risk, roads, aggregation, project size and development ordinances remain.
Take the statement to the authority and surveyor before deciding contract conditions and spending.
Official sources, version and consultation preparation
Verified 2026-10-21; automatic review window 2026-09-18 through 2026-12-31.
The Ministry of Government Legislation OPEN API supplied Decree MST288885 and Rule MST289043 with their full annex texts.
Annex 4’s amendment date of 2026-08-18 is distinct from the current decree version’s 2026-09-18 effective date.
Annex search IDs were 18378917 and 18414485; their detail endpoint returned an HTML shell, so the matching full-statute XML annexes were used for verification.
- Verified Act Article 18 — the latest search MST289913 has a general 2027-03-23 effective date with partial 2026-09-22 commencement; Article 18 was checked as unchanged against earlier MST283757.
- Decree Article 20 and Annexes 2, 4 and 4-2 — scope, numerical criteria, ordinances and facility exceptions.
- Rule Article 10 and Annex 1-3 — survey documentation, less-than-five-year disturbance conversion, two-year forest surveys and slope measurement.
Recheck ordinance changes, current-year statistics and growth adjustments, documents at filing, project purpose, subdivision and aggregation, road access and facility exceptions.
Return to the calculator, save its pending items and take the review to a qualified forest professional and municipal forest department.